a lot of bugfixes and package updates

6 files changed, 33856 insertions, 38 deletions

diff --git a/target/arm/uclibc-ng.config b/target/arm/uclibc-ng.config
index c012bd269..0c62a8e0a 100644
--- a/target/arm/uclibc-ng.config
+++ b/target/arm/uclibc-ng.config
@@ -53,7 +53,7 @@ UCLIBC_HAS_FLOATS=y
 UCLIBC_HAS_SOFT_FLOAT=y
 DO_C99_MATH=y
 # DO_XSI_MATH is not set
-UCLIBC_HAS_FENV=y
+# UCLIBC_HAS_FENV is not set
 KERNEL_HEADERS=""
 HAVE_DOT_CONFIG=y
 
diff --git a/target/linux/config/Config.in.audio b/target/linux/config/Config.in.audio
index 5fc901854..1e08c94b5 100644
--- a/target/linux/config/Config.in.audio
+++ b/target/linux/config/Config.in.audio
@@ -168,36 +168,36 @@ config ADK_KERNEL_SND_BCM2708_SOC_I2S
 config ADK_KERNEL_SND_BCM2708_SOC_HIFIBERRY_AMP
 	tristate "Hifiberry AMP"
 	select ADK_KERNEL_SND_BCM2708_SOC_I2S
-	depends on ADK_TARGET_BOARD_BCM28XX
+	depends on ADK_TARGET_BOARD_BCM28XX && ADK_KERNEL_VERSION_3_18
 
 config ADK_KERNEL_SND_BCM2708_SOC_HIFIBERRY_DAC
 	tristate "Hifiberry DAC"
 	select ADK_KERNEL_SND_BCM2708_SOC_I2S
 	select ADK_KERNEL_SND_SOC_PCM5102A
-	depends on ADK_TARGET_BOARD_BCM28XX
+	depends on ADK_TARGET_BOARD_BCM28XX && ADK_KERNEL_VERSION_3_18
 
 config ADK_KERNEL_SND_BCM2708_SOC_HIFIBERRY_DIGI
 	tristate "Hifiberry DIGI"
 	select ADK_KERNEL_SND_BCM2708_SOC_I2S
 	select ADK_KERNEL_SND_SOC_WM8804
-	depends on ADK_TARGET_BOARD_BCM28XX
+	depends on ADK_TARGET_BOARD_BCM28XX && ADK_KERNEL_VERSION_3_18
 
 config ADK_KERNEL_SND_BCM2708_SOC_RPI_DAC
 	tristate "RPI-DAC"
 	select ADK_KERNEL_SND_BCM2708_SOC_I2S
-	depends on ADK_TARGET_BOARD_BCM28XX
+	depends on ADK_TARGET_BOARD_BCM28XX && ADK_KERNEL_VERSION_3_18
 
 config ADK_KERNEL_SND_BCM2708_SOC_IQAUDIO_DAC
 	tristate "IQAudio-DAC"
 	select ADK_KERNEL_SND_BCM2708_SOC_I2S
 	select ADK_KERNEL_SND_SOC_PCM512x_I2C
-	depends on ADK_TARGET_BOARD_BCM28XX
+	depends on ADK_TARGET_BOARD_BCM28XX && ADK_KERNEL_VERSION_3_18
 
 config ADK_KERNEL_SND_BCM2708_SOC_RPI_PROTO
 	tristate "Rpi-Proto"
 	select ADK_KERNEL_SND_BCM2708_SOC_I2S
 	select ADK_KERNEL_SND_SOC_WM8731
-	depends on ADK_TARGET_BOARD_BCM28XX
+	depends on ADK_TARGET_BOARD_BCM28XX && ADK_KERNEL_VERSION_3_18
 
 config ADK_KERNEL_SND_IMX_SOC
 	bool "IMX6 SoC sound chip"
@@ -212,8 +212,7 @@ config ADK_KERNEL_SND_IMX_SOC
 	select ADK_KERNEL_SND_SOC_FSL_SPDIF
 	select ADK_KERNEL_REGMAP_SPI
 	select ADK_KERNEL_REGMAP_I2C
-	depends on ADK_TARGET_SYSTEM_SOLIDRUN_IMX6
-	depends on ADK_KERNEL_VERSION_3_14
+	depends on ADK_TARGET_SYSTEM_SOLIDRUN_IMX6 && ADK_KERNEL_VERSION_3_14
 	default y if ADK_TARGET_SYSTEM_SOLIDRUN_IMX6
 	default n
 
diff --git a/target/linux/config/Config.in.aufs b/target/linux/config/Config.in.aufs
index 2320cacd8..4e333d3a8 100644
--- a/target/linux/config/Config.in.aufs
+++ b/target/linux/config/Config.in.aufs
@@ -1,8 +1,7 @@
 menu "Overlay filesystems"
 
 config ADK_KERNEL_AUFS_FS
-	prompt "Aufs (Advanced multi layered unification filesystem) support"
-	tristate
+	bool "Aufs (Advanced multi layered unification filesystem) support"
 	help
 	  Aufs is a stackable unification filesystem such as Unionfs,
 	  which unifies several directories and provides a merged single
diff --git a/target/linux/config/Config.in.bluetooth b/target/linux/config/Config.in.bluetooth
index f9c8ea8b6..bcac0b0d0 100644
--- a/target/linux/config/Config.in.bluetooth
+++ b/target/linux/config/Config.in.bluetooth
@@ -1,9 +1,12 @@
 menu "Bluetooth support and drivers"
 depends on ADK_TARGET_WITH_USB || ADK_TARGET_WITH_MINIPCI || ADK_TARGET_WITH_SDIO
 
+config ADK_KERNEL_BT_BREDR
+	bool
+
 config ADK_KERNEL_BT
-	prompt "Bluetooth network stack"
-	tristate
+	tristate "Bluetooth network stack"
+	select ADK_KERNEL_BT_BREDR
 	default n
 	help
 	  Bluetooth is low-cost, low-power, short-range wireless technology.
@@ -23,8 +26,7 @@ config ADK_KERNEL_BT
 	     HIDP Module (Human Interface Device Protocol)
 
 config ADK_KERNEL_BT_L2CAP
-	prompt "L2CAP protocol support"
-	boolean
+	bool "L2CAP protocol support"
 	select ADK_KERNEL_BT
 	default n
 	help
@@ -32,10 +34,8 @@ config ADK_KERNEL_BT_L2CAP
 	  connection oriented and connection-less data transport.  L2CAP
 	  support is required for most Bluetooth applications.
 
-
 config ADK_KERNEL_BT_SCO
-	prompt "SCO link support"
-	boolean
+	bool "SCO link support"
 	select ADK_KERNEL_BT
 	default n
 	help
@@ -43,8 +43,7 @@ config ADK_KERNEL_BT_SCO
 	  required for voice applications like Headset and Audio.
 
 config ADK_KERNEL_BT_RFCOMM
-	prompt "RFCOMM protocol support"
-	tristate
+	tristate "RFCOMM protocol support"
 	select ADK_KERNEL_BT
 	depends on ADK_KERNEL_BT_L2CAP
 	default n
@@ -54,8 +53,7 @@ config ADK_KERNEL_BT_RFCOMM
 	  applications.
 
 config ADK_KERNEL_BT_BNEP
-	prompt "BNEP protocol support"
-	tristate
+	tristate "BNEP protocol support"
 	select ADK_KERNEL_BT
 	depends on ADK_KERNEL_BT_L2CAP
 	default n
@@ -65,8 +63,7 @@ config ADK_KERNEL_BT_BNEP
 	  Bluetooth PAN (Personal Area Network).
 
 config ADK_KERNEL_BT_HIDP
-	prompt "HIDP protocol support"
-	tristate
+	tristate "HIDP protocol support"
 	select ADK_KERNEL_INPUT
 	select ADK_KERNEL_HID
 	select ADK_KERNEL_BT
@@ -78,8 +75,7 @@ config ADK_KERNEL_BT_HIDP
 	  Interface Device Profile.
 
 config ADK_KERNEL_BT_HCIBTSDIO
-	prompt "HCI SDIO driver"
-	tristate
+	tristate "HCI SDIO driver"
 	select ADK_KERNEL_BT
 	depends on ADK_TARGET_WITH_SDIO
 	default n
@@ -89,8 +85,7 @@ config ADK_KERNEL_BT_HCIBTSDIO
 	  SDIO interface.
 
 config ADK_KERNEL_BT_HCIBTUSB
-	prompt "HCI USB driver"
-	tristate
+	tristate "HCI USB driver"
 	select ADK_KERNEL_BT
 	depends on ADK_TARGET_WITH_USB
 	default n
@@ -100,8 +95,7 @@ config ADK_KERNEL_BT_HCIBTUSB
 	  USB interface.
 
 config ADK_KERNEL_BT_HCIUART
-	prompt "HCI UART driver"
-	tristate
+	tristate "HCI UART driver"
 	select ADK_KERNEL_BT
 	default n
 	help
@@ -112,16 +106,14 @@ config ADK_KERNEL_BT_HCIUART
 	  adapter and BrainBoxes Bluetooth PC Card.
 
 config ADK_KERNEL_BT_MRVL
-	prompt "Marvell driver"
-	tristate
+	tristate "Marvell driver"
 	select ADK_KERNEL_BT
 	default n
 	help
 	  Bluetooth Marvell driver.
 
 config ADK_KERNEL_BT_MRVL_SDIO
-	prompt "Marvell SDIO driver"
-	tristate
+	tristate "Marvell SDIO driver"
 	select ADK_PACKAGE_BRCM_BLUETOOTH
 	select ADK_KERNEL_BT_MRVL
 	select ADK_KERNEL_BT_HCIBTSDIO
@@ -131,8 +123,7 @@ config ADK_KERNEL_BT_MRVL_SDIO
 	  Bluetooth Marvell driver.
 
 config ADK_KERNEL_BT_HCIBCM203X
-	prompt "HCI BCM203x USB driver"
-	tristate
+	tristate "HCI BCM203x USB driver"
 	select ADK_KERNEL_FW_LOADER
 	select ADK_KERNEL_BT_HCIBTUSB
 	select ADK_KERNEL_BT
@@ -144,8 +135,7 @@ config ADK_KERNEL_BT_HCIBCM203X
 	  Blutonium based devices.
 
 config ADK_KERNEL_BT_HCIBPA10X
-	prompt "HCI BPA10x USB driver"
-	tristate
+	tristate "HCI BPA10x USB driver"
 	select ADK_KERNEL_BT
 	select ADK_KERNEL_BT_HCIBTUSB
 	default n
diff --git a/target/linux/patches/4.0.4/aufs4.patch b/target/linux/patches/4.0.4/aufs4.patch
new file mode 100644
index 000000000..73b035010
--- /dev/null
+++ b/target/linux/patches/4.0.4/aufs4.patch
@@ -0,0 +1,33819 @@
+diff -Nur linux-4.0.4.orig/Documentation/ABI/testing/debugfs-aufs linux-4.0.4/Documentation/ABI/testing/debugfs-aufs
+--- linux-4.0.4.orig/Documentation/ABI/testing/debugfs-aufs	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/ABI/testing/debugfs-aufs	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,50 @@
++What:		/debug/aufs/si_<id>/
++Date:		March 2009
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		Under /debug/aufs, a directory named si_<id> is created
++		per aufs mount, where <id> is a unique id generated
++		internally.
++
++What:		/debug/aufs/si_<id>/plink
++Date:		Apr 2013
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		It has three lines and shows the information about the
++		pseudo-link. The first line is a single number
++		representing a number of buckets. The second line is a
++		number of pseudo-links per buckets (separated by a
++		blank). The last line is a single number representing a
++		total number of psedo-links.
++		When the aufs mount option 'noplink' is specified, it
++		will show "1\n0\n0\n".
++
++What:		/debug/aufs/si_<id>/xib
++Date:		March 2009
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		It shows the consumed blocks by xib (External Inode Number
++		Bitmap), its block size and file size.
++		When the aufs mount option 'noxino' is specified, it
++		will be empty. About XINO files, see the aufs manual.
++
++What:		/debug/aufs/si_<id>/xino0, xino1 ... xinoN
++Date:		March 2009
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		It shows the consumed blocks by xino (External Inode Number
++		Translation Table), its link count, block size and file
++		size.
++		When the aufs mount option 'noxino' is specified, it
++		will be empty. About XINO files, see the aufs manual.
++
++What:		/debug/aufs/si_<id>/xigen
++Date:		March 2009
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		It shows the consumed blocks by xigen (External Inode
++		Generation Table), its block size and file size.
++		If CONFIG_AUFS_EXPORT is disabled, this entry will not
++		be created.
++		When the aufs mount option 'noxino' is specified, it
++		will be empty. About XINO files, see the aufs manual.
+diff -Nur linux-4.0.4.orig/Documentation/ABI/testing/sysfs-aufs linux-4.0.4/Documentation/ABI/testing/sysfs-aufs
+--- linux-4.0.4.orig/Documentation/ABI/testing/sysfs-aufs	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/ABI/testing/sysfs-aufs	2015-05-30 22:11:29.000000000 +0200
+@@ -0,0 +1,31 @@
++What:		/sys/fs/aufs/si_<id>/
++Date:		March 2009
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		Under /sys/fs/aufs, a directory named si_<id> is created
++		per aufs mount, where <id> is a unique id generated
++		internally.
++
++What:		/sys/fs/aufs/si_<id>/br0, br1 ... brN
++Date:		March 2009
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		It shows the abolute path of a member directory (which
++		is called branch) in aufs, and its permission.
++
++What:		/sys/fs/aufs/si_<id>/brid0, brid1 ... bridN
++Date:		July 2013
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		It shows the id of a member directory (which is called
++		branch) in aufs.
++
++What:		/sys/fs/aufs/si_<id>/xi_path
++Date:		March 2009
++Contact:	J. R. Okajima <hooanon05g@gmail.com>
++Description:
++		It shows the abolute path of XINO (External Inode Number
++		Bitmap, Translation Table and Generation Table) file
++		even if it is the default path.
++		When the aufs mount option 'noxino' is specified, it
++		will be empty. About XINO files, see the aufs manual.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/01intro.txt linux-4.0.4/Documentation/filesystems/aufs/design/01intro.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/01intro.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/01intro.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,157 @@
++
++# Copyright (C) 2005-2015 Junjiro R. Okajima
++
++Introduction
++----------------------------------------
++
++aufs [ei ju: ef es] | [a u f s]
++1. abbrev. for "advanced multi-layered unification filesystem".
++2. abbrev. for "another unionfs".
++3. abbrev. for "auf das" in German which means "on the" in English.
++   Ex. "Butter aufs Brot"(G) means "butter onto bread"(E).
++   But "Filesystem aufs Filesystem" is hard to understand.
++
++AUFS is a filesystem with features:
++- multi layered stackable unification filesystem, the member directory
++  is called as a branch.
++- branch permission and attribute, 'readonly', 'real-readonly',
++  'readwrite', 'whiteout-able', 'link-able whiteout', etc. and their
++  combination.
++- internal "file copy-on-write".
++- logical deletion, whiteout.
++- dynamic branch manipulation, adding, deleting and changing permission.
++- allow bypassing aufs, user's direct branch access.
++- external inode number translation table and bitmap which maintains the
++  persistent aufs inode number.
++- seekable directory, including NFS readdir.
++- file mapping, mmap and sharing pages.
++- pseudo-link, hardlink over branches.
++- loopback mounted filesystem as a branch.
++- several policies to select one among multiple writable branches.
++- revert a single systemcall when an error occurs in aufs.
++- and more...
++
++
++Multi Layered Stackable Unification Filesystem
++----------------------------------------------------------------------
++Most people already knows what it is.
++It is a filesystem which unifies several directories and provides a
++merged single directory. When users access a file, the access will be
++passed/re-directed/converted (sorry, I am not sure which English word is
++correct) to the real file on the member filesystem. The member
++filesystem is called 'lower filesystem' or 'branch' and has a mode
++'readonly' and 'readwrite.' And the deletion for a file on the lower
++readonly branch is handled by creating 'whiteout' on the upper writable
++branch.
++
++On LKML, there have been discussions about UnionMount (Jan Blunck,
++Bharata B Rao and Valerie Aurora) and Unionfs (Erez Zadok). They took
++different approaches to implement the merged-view.
++The former tries putting it into VFS, and the latter implements as a
++separate filesystem.
++(If I misunderstand about these implementations, please let me know and
++I shall correct it. Because it is a long time ago when I read their
++source files last time).
++
++UnionMount's approach will be able to small, but may be hard to share
++branches between several UnionMount since the whiteout in it is
++implemented in the inode on branch filesystem and always
++shared. According to Bharata's post, readdir does not seems to be
++finished yet.
++There are several missing features known in this implementations such as
++- for users, the inode number may change silently. eg. copy-up.
++- link(2) may break by copy-up.
++- read(2) may get an obsoleted filedata (fstat(2) too).
++- fcntl(F_SETLK) may be broken by copy-up.
++- unnecessary copy-up may happen, for example mmap(MAP_PRIVATE) after
++  open(O_RDWR).
++
++In linux-3.18, "overlay" filesystem (formerly known as "overlayfs") was
++merged into mainline. This is another implementation of UnionMount as a
++separated filesystem. All the limitations and known problems which
++UnionMount are equally inherited to "overlay" filesystem.
++
++Unionfs has a longer history. When I started implementing a stackable
++filesystem (Aug 2005), it already existed. It has virtual super_block,
++inode, dentry and file objects and they have an array pointing lower
++same kind objects. After contributing many patches for Unionfs, I
++re-started my project AUFS (Jun 2006).
++
++In AUFS, the structure of filesystem resembles to Unionfs, but I
++implemented my own ideas, approaches and enhancements and it became
++totally different one.
++
++Comparing DM snapshot and fs based implementation
++- the number of bytes to be copied between devices is much smaller.
++- the type of filesystem must be one and only.
++- the fs must be writable, no readonly fs, even for the lower original
++  device. so the compression fs will not be usable. but if we use
++  loopback mount, we may address this issue.
++  for instance,
++	mount /cdrom/squashfs.img /sq
++	losetup /sq/ext2.img
++	losetup /somewhere/cow
++	dmsetup "snapshot /dev/loop0 /dev/loop1 ..."
++- it will be difficult (or needs more operations) to extract the
++  difference between the original device and COW.
++- DM snapshot-merge may help a lot when users try merging. in the
++  fs-layer union, users will use rsync(1).
++
++You may want to read my old paper "Filesystems in LiveCD"
++(http://aufs.sourceforge.net/aufs2/report/sq/sq.pdf).
++
++
++Several characters/aspects/persona of aufs
++----------------------------------------------------------------------
++
++Aufs has several characters, aspects or persona.
++1. a filesystem, callee of VFS helper
++2. sub-VFS, caller of VFS helper for branches
++3. a virtual filesystem which maintains persistent inode number
++4. reader/writer of files on branches such like an application
++
++1. Callee of VFS Helper
++As an ordinary linux filesystem, aufs is a callee of VFS. For instance,
++unlink(2) from an application reaches sys_unlink() kernel function and
++then vfs_unlink() is called. vfs_unlink() is one of VFS helper and it
++calls filesystem specific unlink operation. Actually aufs implements the
++unlink operation but it behaves like a redirector.
++
++2. Caller of VFS Helper for Branches
++aufs_unlink() passes the unlink request to the branch filesystem as if
++it were called from VFS. So the called unlink operation of the branch
++filesystem acts as usual. As a caller of VFS helper, aufs should handle
++every necessary pre/post operation for the branch filesystem.
++- acquire the lock for the parent dir on a branch
++- lookup in a branch
++- revalidate dentry on a branch
++- mnt_want_write() for a branch
++- vfs_unlink() for a branch
++- mnt_drop_write() for a branch
++- release the lock on a branch
++
++3. Persistent Inode Number
++One of the most important issue for a filesystem is to maintain inode
++numbers. This is particularly important to support exporting a
++filesystem via NFS. Aufs is a virtual filesystem which doesn't have a
++backend block device for its own. But some storage is necessary to
++keep and maintain the inode numbers. It may be a large space and may not
++suit to keep in memory. Aufs rents some space from its first writable
++branch filesystem (by default) and creates file(s) on it. These files
++are created by aufs internally and removed soon (currently) keeping
++opened.
++Note: Because these files are removed, they are totally gone after
++      unmounting aufs. It means the inode numbers are not persistent
++      across unmount or reboot. I have a plan to make them really
++      persistent which will be important for aufs on NFS server.
++
++4. Read/Write Files Internally (copy-on-write)
++Because a branch can be readonly, when you write a file on it, aufs will
++"copy-up" it to the upper writable branch internally. And then write the
++originally requested thing to the file. Generally kernel doesn't
++open/read/write file actively. In aufs, even a single write may cause a
++internal "file copy". This behaviour is very similar to cp(1) command.
++
++Some people may think it is better to pass such work to user space
++helper, instead of doing in kernel space. Actually I am still thinking
++about it. But currently I have implemented it in kernel space.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/02struct.txt linux-4.0.4/Documentation/filesystems/aufs/design/02struct.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/02struct.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/02struct.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,245 @@
++
++# Copyright (C) 2005-2015 Junjiro R. Okajima
++
++Basic Aufs Internal Structure
++
++Superblock/Inode/Dentry/File Objects
++----------------------------------------------------------------------
++As like an ordinary filesystem, aufs has its own
++superblock/inode/dentry/file objects. All these objects have a
++dynamically allocated array and store the same kind of pointers to the
++lower filesystem, branch.
++For example, when you build a union with one readwrite branch and one
++readonly, mounted /au, /rw and /ro respectively.
++- /au = /rw + /ro
++- /ro/fileA exists but /rw/fileA
++
++Aufs lookup operation finds /ro/fileA and gets dentry for that. These
++pointers are stored in a aufs dentry. The array in aufs dentry will be,
++- [0] = NULL (because /rw/fileA doesn't exist)
++- [1] = /ro/fileA
++
++This style of an array is essentially same to the aufs
++superblock/inode/dentry/file objects.
++
++Because aufs supports manipulating branches, ie. add/delete/change
++branches dynamically, these objects has its own generation. When
++branches are changed, the generation in aufs superblock is
++incremented. And a generation in other object are compared when it is
++accessed. When a generation in other objects are obsoleted, aufs
++refreshes the internal array.
++
++
++Superblock
++----------------------------------------------------------------------
++Additionally aufs superblock has some data for policies to select one
++among multiple writable branches, XIB files, pseudo-links and kobject.
++See below in detail.
++About the policies which supports copy-down a directory, see
++wbr_policy.txt too.
++
++
++Branch and XINO(External Inode Number Translation Table)
++----------------------------------------------------------------------
++Every branch has its own xino (external inode number translation table)
++file. The xino file is created and unlinked by aufs internally. When two
++members of a union exist on the same filesystem, they share the single
++xino file.
++The struct of a xino file is simple, just a sequence of aufs inode
++numbers which is indexed by the lower inode number.
++In the above sample, assume the inode number of /ro/fileA is i111 and
++aufs assigns the inode number i999 for fileA. Then aufs writes 999 as
++4(8) bytes at 111 * 4(8) bytes offset in the xino file.
++
++When the inode numbers are not contiguous, the xino file will be sparse
++which has a hole in it and doesn't consume as much disk space as it
++might appear. If your branch filesystem consumes disk space for such
++holes, then you should specify 'xino=' option at mounting aufs.
++
++Aufs has a mount option to free the disk blocks for such holes in XINO
++files on tmpfs or ramdisk. But it is not so effective actually. If you
++meet a problem of disk shortage due to XINO files, then you should try
++"tmpfs-ino.patch" (and "vfs-ino.patch" too) in aufs4-standalone.git.
++The patch localizes the assignment inumbers per tmpfs-mount and avoid
++the holes in XINO files.
++
++Also a writable branch has three kinds of "whiteout bases". All these
++are existed when the branch is joined to aufs, and their names are
++whiteout-ed doubly, so that users will never see their names in aufs
++hierarchy.
++1. a regular file which will be hardlinked to all whiteouts.
++2. a directory to store a pseudo-link.
++3. a directory to store an "orphan"-ed file temporary.
++
++1. Whiteout Base
++   When you remove a file on a readonly branch, aufs handles it as a
++   logical deletion and creates a whiteout on the upper writable branch
++   as a hardlink of this file in order not to consume inode on the
++   writable branch.
++2. Pseudo-link Dir
++   See below, Pseudo-link.
++3. Step-Parent Dir
++   When "fileC" exists on the lower readonly branch only and it is
++   opened and removed with its parent dir, and then user writes
++   something into it, then aufs copies-up fileC to this
++   directory. Because there is no other dir to store fileC. After
++   creating a file under this dir, the file is unlinked.
++
++Because aufs supports manipulating branches, ie. add/delete/change
++dynamically, a branch has its own id. When the branch order changes,
++aufs finds the new index by searching the branch id.
++
++
++Pseudo-link
++----------------------------------------------------------------------
++Assume "fileA" exists on the lower readonly branch only and it is
++hardlinked to "fileB" on the branch. When you write something to fileA,
++aufs copies-up it to the upper writable branch. Additionally aufs
++creates a hardlink under the Pseudo-link Directory of the writable
++branch. The inode of a pseudo-link is kept in aufs super_block as a
++simple list. If fileB is read after unlinking fileA, aufs returns
++filedata from the pseudo-link instead of the lower readonly
++branch. Because the pseudo-link is based upon the inode, to keep the
++inode number by xino (see above) is essentially necessary.
++
++All the hardlinks under the Pseudo-link Directory of the writable branch
++should be restored in a proper location later. Aufs provides a utility
++to do this. The userspace helpers executed at remounting and unmounting
++aufs by default.
++During this utility is running, it puts aufs into the pseudo-link
++maintenance mode. In this mode, only the process which began the
++maintenance mode (and its child processes) is allowed to operate in
++aufs. Some other processes which are not related to the pseudo-link will
++be allowed to run too, but the rest have to return an error or wait
++until the maintenance mode ends. If a process already acquires an inode
++mutex (in VFS), it has to return an error.
++
++
++XIB(external inode number bitmap)
++----------------------------------------------------------------------
++Addition to the xino file per a branch, aufs has an external inode number
++bitmap in a superblock object. It is also an internal file such like a
++xino file.
++It is a simple bitmap to mark whether the aufs inode number is in-use or
++not.
++To reduce the file I/O, aufs prepares a single memory page to cache xib.
++
++As well as XINO files, aufs has a feature to truncate/refresh XIB to
++reduce the number of consumed disk blocks for these files.
++
++
++Virtual or Vertical Dir, and Readdir in Userspace
++----------------------------------------------------------------------
++In order to support multiple layers (branches), aufs readdir operation
++constructs a virtual dir block on memory. For readdir, aufs calls
++vfs_readdir() internally for each dir on branches, merges their entries
++with eliminating the whiteout-ed ones, and sets it to file (dir)
++object. So the file object has its entry list until it is closed. The
++entry list will be updated when the file position is zero and becomes
++obsoleted. This decision is made in aufs automatically.
++
++The dynamically allocated memory block for the name of entries has a
++unit of 512 bytes (by default) and stores the names contiguously (no
++padding). Another block for each entry is handled by kmem_cache too.
++During building dir blocks, aufs creates hash list and judging whether
++the entry is whiteouted by its upper branch or already listed.
++The merged result is cached in the corresponding inode object and
++maintained by a customizable life-time option.
++
++Some people may call it can be a security hole or invite DoS attack
++since the opened and once readdir-ed dir (file object) holds its entry
++list and becomes a pressure for system memory. But I'd say it is similar
++to files under /proc or /sys. The virtual files in them also holds a
++memory page (generally) while they are opened. When an idea to reduce
++memory for them is introduced, it will be applied to aufs too.
++For those who really hate this situation, I've developed readdir(3)
++library which operates this merging in userspace. You just need to set
++LD_PRELOAD environment variable, and aufs will not consume no memory in
++kernel space for readdir(3).
++
++
++Workqueue
++----------------------------------------------------------------------
++Aufs sometimes requires privilege access to a branch. For instance,
++in copy-up/down operation. When a user process is going to make changes
++to a file which exists in the lower readonly branch only, and the mode
++of one of ancestor directories may not be writable by a user
++process. Here aufs copy-up the file with its ancestors and they may
++require privilege to set its owner/group/mode/etc.
++This is a typical case of a application character of aufs (see
++Introduction).
++
++Aufs uses workqueue synchronously for this case. It creates its own
++workqueue. The workqueue is a kernel thread and has privilege. Aufs
++passes the request to call mkdir or write (for example), and wait for
++its completion. This approach solves a problem of a signal handler
++simply.
++If aufs didn't adopt the workqueue and changed the privilege of the
++process, then the process may receive the unexpected SIGXFSZ or other
++signals.
++
++Also aufs uses the system global workqueue ("events" kernel thread) too
++for asynchronous tasks, such like handling inotify/fsnotify, re-creating a
++whiteout base and etc. This is unrelated to a privilege.
++Most of aufs operation tries acquiring a rw_semaphore for aufs
++superblock at the beginning, at the same time waits for the completion
++of all queued asynchronous tasks.
++
++
++Whiteout
++----------------------------------------------------------------------
++The whiteout in aufs is very similar to Unionfs's. That is represented
++by its filename. UnionMount takes an approach of a file mode, but I am
++afraid several utilities (find(1) or something) will have to support it.
++
++Basically the whiteout represents "logical deletion" which stops aufs to
++lookup further, but also it represents "dir is opaque" which also stop
++further lookup.
++
++In aufs, rmdir(2) and rename(2) for dir uses whiteout alternatively.
++In order to make several functions in a single systemcall to be
++revertible, aufs adopts an approach to rename a directory to a temporary
++unique whiteouted name.
++For example, in rename(2) dir where the target dir already existed, aufs
++renames the target dir to a temporary unique whiteouted name before the
++actual rename on a branch, and then handles other actions (make it opaque,
++update the attributes, etc). If an error happens in these actions, aufs
++simply renames the whiteouted name back and returns an error. If all are
++succeeded, aufs registers a function to remove the whiteouted unique
++temporary name completely and asynchronously to the system global
++workqueue.
++
++
++Copy-up
++----------------------------------------------------------------------
++It is a well-known feature or concept.
++When user modifies a file on a readonly branch, aufs operate "copy-up"
++internally and makes change to the new file on the upper writable branch.
++When the trigger systemcall does not update the timestamps of the parent
++dir, aufs reverts it after copy-up.
++
++
++Move-down (aufs3.9 and later)
++----------------------------------------------------------------------
++"Copy-up" is one of the essential feature in aufs. It copies a file from
++the lower readonly branch to the upper writable branch when a user
++changes something about the file.
++"Move-down" is an opposite action of copy-up. Basically this action is
++ran manually instead of automatically and internally.
++For desgin and implementation, aufs has to consider these issues.
++- whiteout for the file may exist on the lower branch.
++- ancestor directories may not exist on the lower branch.
++- diropq for the ancestor directories may exist on the upper branch.
++- free space on the lower branch will reduce.
++- another access to the file may happen during moving-down, including
++  UDBA (see "Revalidate Dentry and UDBA").
++- the file should not be hard-linked nor pseudo-linked. they should be
++  handled by auplink utility later.
++
++Sometimes users want to move-down a file from the upper writable branch
++to the lower readonly or writable branch. For instance,
++- the free space of the upper writable branch is going to run out.
++- create a new intermediate branch between the upper and lower branch.
++- etc.
++
++For this purpose, use "aumvdown" command in aufs-util.git.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/03atomic_open.txt linux-4.0.4/Documentation/filesystems/aufs/design/03atomic_open.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/03atomic_open.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/03atomic_open.txt	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,72 @@
++
++# Copyright (C) 2015 Junjiro R. Okajima
++
++Support for a branch who has its ->atomic_open()
++----------------------------------------------------------------------
++The filesystems who implement its ->atomic_open() are not majority. For
++example NFSv4 does, and aufs should call NFSv4 ->atomic_open,
++particularly for open(O_CREAT|O_EXCL, 0400) case. Other than
++->atomic_open(), NFSv4 returns an error for this open(2). While I am not
++sure whether all filesystems who have ->atomic_open() behave like this,
++but NFSv4 surely returns the error.
++
++In order to support ->atomic_open() for aufs, there are a few
++approaches.
++
++A. Introduce aufs_atomic_open()
++   - calls one of VFS:do_last(), lookup_open() or atomic_open() for
++     branch fs.
++B. Introduce aufs_atomic_open() calling create, open and chmod. this is
++   an aufs user Pip Cet's approach
++   - calls aufs_create(), VFS finish_open() and notify_change().
++   - pass fake-mode to finish_open(), and then correct the mode by
++     notify_change().
++C. Extend aufs_open() to call branch fs's ->atomic_open()
++   - no aufs_atomic_open().
++   - aufs_lookup() registers the TID to an aufs internal object.
++   - aufs_create() does nothing when the matching TID is registered, but
++     registers the mode.
++   - aufs_open() calls branch fs's ->atomic_open() when the matching
++     TID is registered.
++D. Extend aufs_open() to re-try branch fs's ->open() with superuser's
++   credential
++   - no aufs_atomic_open().
++   - aufs_create() registers the TID to an internal object. this info
++     represents "this process created this file just now."
++   - when aufs gets EACCES from branch fs's ->open(), then confirm the
++     registered TID and re-try open() with superuser's credential.
++
++Pros and cons for each approach.
++
++A.
++   - straightforward but highly depends upon VFS internal.
++   - the atomic behavaiour is kept.
++   - some of parameters such as nameidata are hard to reproduce for
++     branch fs.
++   - large overhead.
++B.
++   - easy to implement.
++   - the atomic behavaiour is lost.
++C.
++   - the atomic behavaiour is kept.
++   - dirty and tricky.
++   - VFS checks whether the file is created correctly after calling
++     ->create(), which means this approach doesn't work.
++D.
++   - easy to implement.
++   - the atomic behavaiour is lost.
++   - to open a file with superuser's credential and give it to a user
++     process is a bad idea, since the file object keeps the credential
++     in it. It may affect LSM or something. This approach doesn't work
++     either.
++
++The approach A is ideal, but it hard to implement. So here is a
++variation of A, which is to be implemented.
++
++A-1. Introduce aufs_atomic_open()
++     - calls branch fs ->atomic_open() if exists. otherwise calls
++       vfs_create() and finish_open().
++     - the demerit is that the several checks after branch fs
++       ->atomic_open() are lost. in the ordinary case, the checks are
++       done by VFS:do_last(), lookup_open() and atomic_open(). some can
++       be implemented in aufs, but not all I am afraid.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/03lookup.txt linux-4.0.4/Documentation/filesystems/aufs/design/03lookup.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/03lookup.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/03lookup.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,100 @@
++
++# Copyright (C) 2005-2015 Junjiro R. Okajima
++
++Lookup in a Branch
++----------------------------------------------------------------------
++Since aufs has a character of sub-VFS (see Introduction), it operates
++lookup for branches as VFS does. It may be a heavy work. But almost all
++lookup operation in aufs is the simplest case, ie. lookup only an entry
++directly connected to its parent. Digging down the directory hierarchy
++is unnecessary. VFS has a function lookup_one_len() for that use, and
++aufs calls it.
++
++When a branch is a remote filesystem, aufs basically relies upon its
++->d_revalidate(), also aufs forces the hardest revalidate tests for
++them.
++For d_revalidate, aufs implements three levels of revalidate tests. See
++"Revalidate Dentry and UDBA" in detail.
++
++
++Test Only the Highest One for the Directory Permission (dirperm1 option)
++----------------------------------------------------------------------
++Let's try case study.
++- aufs has two branches, upper readwrite and lower readonly.
++  /au = /rw + /ro
++- "dirA" exists under /ro, but /rw. and its mode is 0700.
++- user invoked "chmod a+rx /au/dirA"
++- the internal copy-up is activated and "/rw/dirA" is created and its
++  permission bits are set to world readable.
++- then "/au/dirA" becomes world readable?
++
++In this case, /ro/dirA is still 0700 since it exists in readonly branch,
++or it may be a natively readonly filesystem. If aufs respects the lower
++branch, it should not respond readdir request from other users. But user
++allowed it by chmod. Should really aufs rejects showing the entries
++under /ro/dirA?
++
++To be honest, I don't have a good solution for this case. So aufs
++implements 'dirperm1' and 'nodirperm1' mount options, and leave it to
++users.
++When dirperm1 is specified, aufs checks only the highest one for the
++directory permission, and shows the entries. Otherwise, as usual, checks
++every dir existing on all branches and rejects the request.
++
++As a side effect, dirperm1 option improves the performance of aufs
++because the number of permission check is reduced when the number of
++branch is many.
++
++
++Revalidate Dentry and UDBA (User's Direct Branch Access)
++----------------------------------------------------------------------
++Generally VFS helpers re-validate a dentry as a part of lookup.
++0. digging down the directory hierarchy.
++1. lock the parent dir by its i_mutex.
++2. lookup the final (child) entry.
++3. revalidate it.
++4. call the actual operation (create, unlink, etc.)
++5. unlock the parent dir
++
++If the filesystem implements its ->d_revalidate() (step 3), then it is
++called. Actually aufs implements it and checks the dentry on a branch is
++still valid.
++But it is not enough. Because aufs has to release the lock for the
++parent dir on a branch at the end of ->lookup() (step 2) and
++->d_revalidate() (step 3) while the i_mutex of the aufs dir is still
++held by VFS.
++If the file on a branch is changed directly, eg. bypassing aufs, after
++aufs released the lock, then the subsequent operation may cause
++something unpleasant result.
++
++This situation is a result of VFS architecture, ->lookup() and
++->d_revalidate() is separated. But I never say it is wrong. It is a good
++design from VFS's point of view. It is just not suitable for sub-VFS
++character in aufs.
++
++Aufs supports such case by three level of revalidation which is
++selectable by user.
++1. Simple Revalidate
++   Addition to the native flow in VFS's, confirm the child-parent
++   relationship on the branch just after locking the parent dir on the
++   branch in the "actual operation" (step 4). When this validation
++   fails, aufs returns EBUSY. ->d_revalidate() (step 3) in aufs still
++   checks the validation of the dentry on branches.
++2. Monitor Changes Internally by Inotify/Fsnotify
++   Addition to above, in the "actual operation" (step 4) aufs re-lookup
++   the dentry on the branch, and returns EBUSY if it finds different
++   dentry.
++   Additionally, aufs sets the inotify/fsnotify watch for every dir on branches
++   during it is in cache. When the event is notified, aufs registers a
++   function to kernel 'events' thread by schedule_work(). And the
++   function sets some special status to the cached aufs dentry and inode
++   private data. If they are not cached, then aufs has nothing to
++   do. When the same file is accessed through aufs (step 0-3) later,
++   aufs will detect the status and refresh all necessary data.
++   In this mode, aufs has to ignore the event which is fired by aufs
++   itself.
++3. No Extra Validation
++   This is the simplest test and doesn't add any additional revalidation
++   test, and skip the revalidation in step 4. It is useful and improves
++   aufs performance when system surely hide the aufs branches from user,
++   by over-mounting something (or another method).
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/04branch.txt linux-4.0.4/Documentation/filesystems/aufs/design/04branch.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/04branch.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/04branch.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,61 @@
++
++# Copyright (C) 2005-2015 Junjiro R. Okajima
++
++Branch Manipulation
++
++Since aufs supports dynamic branch manipulation, ie. add/remove a branch
++and changing its permission/attribute, there are a lot of works to do.
++
++
++Add a Branch
++----------------------------------------------------------------------
++o Confirm the adding dir exists outside of aufs, including loopback
++  mount, and its various attributes.
++o Initialize the xino file and whiteout bases if necessary.
++  See struct.txt.
++
++o Check the owner/group/mode of the directory
++  When the owner/group/mode of the adding directory differs from the
++  existing branch, aufs issues a warning because it may impose a
++  security risk.
++  For example, when a upper writable branch has a world writable empty
++  top directory, a malicious user can create any files on the writable
++  branch directly, like copy-up and modify manually. If something like
++  /etc/{passwd,shadow} exists on the lower readonly branch but the upper
++  writable branch, and the writable branch is world-writable, then a
++  malicious guy may create /etc/passwd on the writable branch directly
++  and the infected file will be valid in aufs.
++  I am afraid it can be a security issue, but aufs can do nothing except
++  producing a warning.
++
++
++Delete a Branch
++----------------------------------------------------------------------
++o Confirm the deleting branch is not busy
++  To be general, there is one merit to adopt "remount" interface to
++  manipulate branches. It is to discard caches. At deleting a branch,
++  aufs checks the still cached (and connected) dentries and inodes. If
++  there are any, then they are all in-use. An inode without its
++  corresponding dentry can be alive alone (for example, inotify/fsnotify case).
++
++  For the cached one, aufs checks whether the same named entry exists on
++  other branches.
++  If the cached one is a directory, because aufs provides a merged view
++  to users, as long as one dir is left on any branch aufs can show the
++  dir to users. In this case, the branch can be removed from aufs.
++  Otherwise aufs rejects deleting the branch.
++
++  If any file on the deleting branch is opened by aufs, then aufs
++  rejects deleting.
++
++
++Modify the Permission of a Branch
++----------------------------------------------------------------------
++o Re-initialize or remove the xino file and whiteout bases if necessary.
++  See struct.txt.
++
++o rw --> ro: Confirm the modifying branch is not busy
++  Aufs rejects the request if any of these conditions are true.
++  - a file on the branch is mmap-ed.
++  - a regular file on the branch is opened for write and there is no
++    same named entry on the upper branch.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/05wbr_policy.txt linux-4.0.4/Documentation/filesystems/aufs/design/05wbr_policy.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/05wbr_policy.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/05wbr_policy.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,51 @@
++
++# Copyright (C) 2005-2015 Junjiro R. Okajima
++
++Policies to Select One among Multiple Writable Branches
++----------------------------------------------------------------------
++When the number of writable branch is more than one, aufs has to decide
++the target branch for file creation or copy-up. By default, the highest
++writable branch which has the parent (or ancestor) dir of the target
++file is chosen (top-down-parent policy).
++By user's request, aufs implements some other policies to select the
++writable branch, for file creation several policies, round-robin,
++most-free-space, and other policies. For copy-up, top-down-parent,
++bottom-up-parent, bottom-up and others.
++
++As expected, the round-robin policy selects the branch in circular. When
++you have two writable branches and creates 10 new files, 5 files will be
++created for each branch. mkdir(2) systemcall is an exception. When you
++create 10 new directories, all will be created on the same branch.
++And the most-free-space policy selects the one which has most free
++space among the writable branches. The amount of free space will be
++checked by aufs internally, and users can specify its time interval.
++
++The policies for copy-up is more simple,
++top-down-parent is equivalent to the same named on in create policy,
++bottom-up-parent selects the writable branch where the parent dir
++exists and the nearest upper one from the copyup-source,
++bottom-up selects the nearest upper writable branch from the
++copyup-source, regardless the existence of the parent dir.
++
++There are some rules or exceptions to apply these policies.
++- If there is a readonly branch above the policy-selected branch and
++  the parent dir is marked as opaque (a variation of whiteout), or the
++  target (creating) file is whiteout-ed on the upper readonly branch,
++  then the result of the policy is ignored and the target file will be
++  created on the nearest upper writable branch than the readonly branch.
++- If there is a writable branch above the policy-selected branch and
++  the parent dir is marked as opaque or the target file is whiteouted
++  on the branch, then the result of the policy is ignored and the target
++  file will be created on the highest one among the upper writable
++  branches who has diropq or whiteout. In case of whiteout, aufs removes
++  it as usual.
++- link(2) and rename(2) systemcalls are exceptions in every policy.
++  They try selecting the branch where the source exists as possible
++  since copyup a large file will take long time. If it can't be,
++  ie. the branch where the source exists is readonly, then they will
++  follow the copyup policy.
++- There is an exception for rename(2) when the target exists.
++  If the rename target exists, aufs compares the index of the branches
++  where the source and the target exists and selects the higher
++  one. If the selected branch is readonly, then aufs follows the
++  copyup policy.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/06fhsm.txt linux-4.0.4/Documentation/filesystems/aufs/design/06fhsm.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/06fhsm.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/06fhsm.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,105 @@
++
++# Copyright (C) 2011-2015 Junjiro R. Okajima
++
++File-based Hierarchical Storage Management (FHSM)
++----------------------------------------------------------------------
++Hierarchical Storage Management (or HSM) is a well-known feature in the
++storage world. Aufs provides this feature as file-based with multiple
++writable branches, based upon the principle of "Colder, the Lower".
++Here the word "colder" means that the less used files, and "lower" means
++that the position in the order of the stacked branches vertically.
++These multiple writable branches are prioritized, ie. the topmost one
++should be the fastest drive and be used heavily.
++
++o Characters in aufs FHSM story
++- aufs itself and a new branch attribute.
++- a new ioctl interface to move-down and to establish a connection with
++  the daemon ("move-down" is a converse of "copy-up").
++- userspace tool and daemon.
++
++The userspace daemon establishes a connection with aufs and waits for
++the notification. The notified information is very similar to struct
++statfs containing the number of consumed blocks and inodes.
++When the consumed blocks/inodes of a branch exceeds the user-specified
++upper watermark, the daemon activates its move-down process until the
++consumed blocks/inodes reaches the user-specified lower watermark.
++
++The actual move-down is done by aufs based upon the request from
++user-space since we need to maintain the inode number and the internal
++pointer arrays in aufs.
++
++Currently aufs FHSM handles the regular files only. Additionally they
++must not be hard-linked nor pseudo-linked.
++
++
++o Cowork of aufs and the user-space daemon
++  During the userspace daemon established the connection, aufs sends a
++  small notification to it whenever aufs writes something into the
++  writable branch. But it may cost high since aufs issues statfs(2)
++  internally. So user can specify a new option to cache the
++  info. Actually the notification is controlled by these factors.
++  + the specified cache time.
++  + classified as "force" by aufs internally.
++  Until the specified time expires, aufs doesn't send the info
++  except the forced cases. When aufs decide forcing, the info is always
++  notified to userspace.
++  For example, the number of free inodes is generally large enough and
++  the shortage of it happens rarely. So aufs doesn't force the
++  notification when creating a new file, directory and others. This is
++  the typical case which aufs doesn't force.
++  When aufs writes the actual filedata and the files consumes any of new
++  blocks, the aufs forces notifying.
++
++
++o Interfaces in aufs
++- New branch attribute.
++  + fhsm
++    Specifies that the branch is managed by FHSM feature. In other word,
++    participant in the FHSM.
++    When nofhsm is set to the branch, it will not be the source/target
++    branch of the move-down operation. This attribute is set
++    independently from coo and moo attributes, and if you want full
++    FHSM, you should specify them as well.
++- New mount option.
++  + fhsm_sec
++    Specifies a second to suppress many less important info to be
++    notified.
++- New ioctl.
++  + AUFS_CTL_FHSM_FD
++    create a new file descriptor which userspace can read the notification
++    (a subset of struct statfs) from aufs.
++- Module parameter 'brs'
++  It has to be set to 1. Otherwise the new mount option 'fhsm' will not
++  be set.
++- mount helpers /sbin/mount.aufs and /sbin/umount.aufs
++  When there are two or more branches with fhsm attributes,
++  /sbin/mount.aufs invokes the user-space daemon and /sbin/umount.aufs
++  terminates it. As a result of remounting and branch-manipulation, the
++  number of branches with fhsm attribute can be one. In this case,
++  /sbin/mount.aufs will terminate the user-space daemon.
++
++
++Finally the operation is done as these steps in kernel-space.
++- make sure that,
++  + no one else is using the file.
++  + the file is not hard-linked.
++  + the file is not pseudo-linked.
++  + the file is a regular file.
++  + the parent dir is not opaqued.
++- find the target writable branch.
++- make sure the file is not whiteout-ed by the upper (than the target)
++  branch.
++- make the parent dir on the target branch.
++- mutex lock the inode on the branch.
++- unlink the whiteout on the target branch (if exists).
++- lookup and create the whiteout-ed temporary name on the target branch.
++- copy the file as the whiteout-ed temporary name on the target branch.
++- rename the whiteout-ed temporary name to the original name.
++- unlink the file on the source branch.
++- maintain the internal pointer array and the external inode number
++  table (XINO).
++- maintain the timestamps and other attributes of the parent dir and the
++  file.
++
++And of course, in every step, an error may happen. So the operation
++should restore the original file state after an error happens.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/06mmap.txt linux-4.0.4/Documentation/filesystems/aufs/design/06mmap.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/06mmap.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/06mmap.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,33 @@
++
++# Copyright (C) 2005-2015 Junjiro R. Okajima
++
++mmap(2) -- File Memory Mapping
++----------------------------------------------------------------------
++In aufs, the file-mapped pages are handled by a branch fs directly, no
++interaction with aufs. It means aufs_mmap() calls the branch fs's
++->mmap().
++This approach is simple and good, but there is one problem.
++Under /proc, several entries show the mmapped files by its path (with
++device and inode number), and the printed path will be the path on the
++branch fs's instead of virtual aufs's.
++This is not a problem in most cases, but some utilities lsof(1) (and its
++user) may expect the path on aufs.
++
++To address this issue, aufs adds a new member called vm_prfile in struct
++vm_area_struct (and struct vm_region). The original vm_file points to
++the file on the branch fs in order to handle everything correctly as
++usual. The new vm_prfile points to a virtual file in aufs, and the
++show-functions in procfs refers to vm_prfile if it is set.
++Also we need to maintain several other places where touching vm_file
++such like
++- fork()/clone() copies vma and the reference count of vm_file is
++  incremented.
++- merging vma maintains the ref count too.
++
++This is not a good approach. It just fakes the printed path. But it
++leaves all behaviour around f_mapping unchanged. This is surely an
++advantage.
++Actually aufs had adopted another complicated approach which calls
++generic_file_mmap() and handles struct vm_operations_struct. In this
++approach, aufs met a hard problem and I could not solve it without
++switching the approach.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/06xattr.txt linux-4.0.4/Documentation/filesystems/aufs/design/06xattr.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/06xattr.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/06xattr.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,81 @@
++
++# Copyright (C) 2014-2015 Junjiro R. Okajima
++
++Listing XATTR/EA and getting the value
++----------------------------------------------------------------------
++For the inode standard attributes (owner, group, timestamps, etc.), aufs
++shows the values from the topmost existing file. This behaviour is good
++for the non-dir entries since the bahaviour exactly matches the shown
++information. But for the directories, aufs considers all the same named
++entries on the lower branches. Which means, if one of the lower entry
++rejects readdir call, then aufs returns an error even if the topmost
++entry allows it. This behaviour is necessary to respect the branch fs's
++security, but can make users confused since the user-visible standard
++attributes don't match the behaviour.
++To address this issue, aufs has a mount option called dirperm1 which
++checks the permission for the topmost entry only, and ignores the lower
++entry's permission.
++
++A similar issue can happen around XATTR.
++getxattr(2) and listxattr(2) families behave as if dirperm1 option is
++always set. Otherwise these very unpleasant situation would happen.
++- listxattr(2) may return the duplicated entries.
++- users may not be able to remove or reset the XATTR forever,
++
++
++XATTR/EA support in the internal (copy,move)-(up,down)
++----------------------------------------------------------------------
++Generally the extended attributes of inode are categorized as these.
++- "security" for LSM and capability.
++- "system" for posix ACL, 'acl' mount option is required for the branch
++  fs generally.
++- "trusted" for userspace, CAP_SYS_ADMIN is required.
++- "user" for userspace, 'user_xattr' mount option is required for the
++  branch fs generally.
++
++Moreover there are some other categories. Aufs handles these rather
++unpopular categories as the ordinary ones, ie. there is no special
++condition nor exception.
++
++In copy-up, the support for XATTR on the dst branch may differ from the
++src branch. In this case, the copy-up operation will get an error and
++the original user operation which triggered the copy-up will fail. It
++can happen that even all copy-up will fail.
++When both of src and dst branches support XATTR and if an error occurs
++during copying XATTR, then the copy-up should fail obviously. That is a
++good reason and aufs should return an error to userspace. But when only
++the src branch support that XATTR, aufs should not return an error.
++For example, the src branch supports ACL but the dst branch doesn't
++because the dst branch may natively un-support it or temporary
++un-support it due to "noacl" mount option. Of course, the dst branch fs
++may NOT return an error even if the XATTR is not supported. It is
++totally up to the branch fs.
++
++Anyway when the aufs internal copy-up gets an error from the dst branch
++fs, then aufs tries removing the just copied entry and returns the error
++to the userspace. The worst case of this situation will be all copy-up
++will fail.
++
++For the copy-up operation, there two basic approaches.
++- copy the specified XATTR only (by category above), and return the
++  error unconditionally if it happens.
++- copy all XATTR, and ignore the error on the specified category only.
++
++In order to support XATTR and to implement the correct behaviour, aufs
++chooses the latter approach and introduces some new branch attributes,
++"icexsec", "icexsys", "icextr", "icexusr", and "icexoth".
++They correspond to the XATTR namespaces (see above). Additionally, to be
++convenient, "icex" is also provided which means all "icex*" attributes
++are set (here the word "icex" stands for "ignore copy-error on XATTR").
++
++The meaning of these attributes is to ignore the error from setting
++XATTR on that branch.
++Note that aufs tries copying all XATTR unconditionally, and ignores the
++error from the dst branch according to the specified attributes.
++
++Some XATTR may have its default value. The default value may come from
++the parent dir or the environment. If the default value is set at the
++file creating-time, it will be overwritten by copy-up.
++Some contradiction may happen I am afraid.
++Do we need another attribute to stop copying XATTR? I am unsure. For
++now, aufs implements the branch attributes to ignore the error.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/07export.txt linux-4.0.4/Documentation/filesystems/aufs/design/07export.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/07export.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/07export.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,45 @@
++
++# Copyright (C) 2005-2015 Junjiro R. Okajima
++
++Export Aufs via NFS
++----------------------------------------------------------------------
++Here is an approach.
++- like xino/xib, add a new file 'xigen' which stores aufs inode
++  generation.
++- iget_locked(): initialize aufs inode generation for a new inode, and
++  store it in xigen file.
++- destroy_inode(): increment aufs inode generation and store it in xigen
++  file. it is necessary even if it is not unlinked, because any data of
++  inode may be changed by UDBA.
++- encode_fh(): for a root dir, simply return FILEID_ROOT. otherwise
++  build file handle by
++  + branch id (4 bytes)
++  + superblock generation (4 bytes)
++  + inode number (4 or 8 bytes)
++  + parent dir inode number (4 or 8 bytes)
++  + inode generation (4 bytes))
++  + return value of exportfs_encode_fh() for the parent on a branch (4
++    bytes)
++  + file handle for a branch (by exportfs_encode_fh())
++- fh_to_dentry():
++  + find the index of a branch from its id in handle, and check it is
++    still exist in aufs.
++  + 1st level: get the inode number from handle and search it in cache.
++  + 2nd level: if not found in cache, get the parent inode number from
++    the handle and search it in cache. and then open the found parent
++    dir, find the matching inode number by vfs_readdir() and get its
++    name, and call lookup_one_len() for the target dentry.
++  + 3rd level: if the parent dir is not cached, call
++    exportfs_decode_fh() for a branch and get the parent on a branch,
++    build a pathname of it, convert it a pathname in aufs, call
++    path_lookup(). now aufs gets a parent dir dentry, then handle it as
++    the 2nd level.
++  + to open the dir, aufs needs struct vfsmount. aufs keeps vfsmount
++    for every branch, but not itself. to get this, (currently) aufs
++    searches in current->nsproxy->mnt_ns list. it may not be a good
++    idea, but I didn't get other approach.
++  + test the generation of the gotten inode.
++- every inode operation: they may get EBUSY due to UDBA. in this case,
++  convert it into ESTALE for NFSD.
++- readdir(): call lockdep_on/off() because filldir in NFSD calls
++  lookup_one_len(), vfs_getattr(), encode_fh() and others.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/08shwh.txt linux-4.0.4/Documentation/filesystems/aufs/design/08shwh.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/08shwh.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/08shwh.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,39 @@
++
++# Copyright (C) 2005-2015 Junjiro R. Okajima
++
++Show Whiteout Mode (shwh)
++----------------------------------------------------------------------
++Generally aufs hides the name of whiteouts. But in some cases, to show
++them is very useful for users. For instance, creating a new middle layer
++(branch) by merging existing layers.
++
++(borrowing aufs1 HOW-TO from a user, Michael Towers)
++When you have three branches,
++- Bottom: 'system', squashfs (underlying base system), read-only
++- Middle: 'mods', squashfs, read-only
++- Top: 'overlay', ram (tmpfs), read-write
++
++The top layer is loaded at boot time and saved at shutdown, to preserve
++the changes made to the system during the session.
++When larger changes have been made, or smaller changes have accumulated,
++the size of the saved top layer data grows. At this point, it would be
++nice to be able to merge the two overlay branches ('mods' and 'overlay')
++and rewrite the 'mods' squashfs, clearing the top layer and thus
++restoring save and load speed.
++
++This merging is simplified by the use of another aufs mount, of just the
++two overlay branches using the 'shwh' option.
++# mount -t aufs -o ro,shwh,br:/livesys/overlay=ro+wh:/livesys/mods=rr+wh \
++	aufs /livesys/merge_union
++
++A merged view of these two branches is then available at
++/livesys/merge_union, and the new feature is that the whiteouts are
++visible!
++Note that in 'shwh' mode the aufs mount must be 'ro', which will disable
++writing to all branches. Also the default mode for all branches is 'ro'.
++It is now possible to save the combined contents of the two overlay
++branches to a new squashfs, e.g.:
++# mksquashfs /livesys/merge_union /path/to/newmods.squash
++
++This new squashfs archive can be stored on the boot device and the
++initramfs will use it to replace the old one at the next boot.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/design/10dynop.txt linux-4.0.4/Documentation/filesystems/aufs/design/10dynop.txt
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/design/10dynop.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/design/10dynop.txt	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,34 @@
++
++# Copyright (C) 2010-2015 Junjiro R. Okajima
++
++Dynamically customizable FS operations
++----------------------------------------------------------------------
++Generally FS operations (struct inode_operations, struct
++address_space_operations, struct file_operations, etc.) are defined as
++"static const", but it never means that FS have only one set of
++operation. Some FS have multiple sets of them. For instance, ext2 has
++three sets, one for XIP, for NOBH, and for normal.
++Since aufs overrides and redirects these operations, sometimes aufs has
++to change its behaviour according to the branch FS type. More importantly
++VFS acts differently if a function (member in the struct) is set or
++not. It means aufs should have several sets of operations and select one
++among them according to the branch FS definition.
++
++In order to solve this problem and not to affect the behaviour of VFS,
++aufs defines these operations dynamically. For instance, aufs defines
++dummy direct_IO function for struct address_space_operations, but it may
++not be set to the address_space_operations actually. When the branch FS
++doesn't have it, aufs doesn't set it to its address_space_operations
++while the function definition itself is still alive. So the behaviour
++itself will not change, and it will return an error when direct_IO is
++not set.
++
++The lifetime of these dynamically generated operation object is
++maintained by aufs branch object. When the branch is removed from aufs,
++the reference counter of the object is decremented. When it reaches
++zero, the dynamically generated operation object will be freed.
++
++This approach is designed to support AIO (io_submit), Direct I/O and
++XIP (DAX) mainly.
++Currently this approach is applied to address_space_operations for
++regular files only.
+diff -Nur linux-4.0.4.orig/Documentation/filesystems/aufs/README linux-4.0.4/Documentation/filesystems/aufs/README
+--- linux-4.0.4.orig/Documentation/filesystems/aufs/README	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/Documentation/filesystems/aufs/README	2015-05-30 22:11:29.000000000 +0200
+@@ -0,0 +1,383 @@
++
++Aufs4 -- advanced multi layered unification filesystem version 4.x
++http://aufs.sf.net
++Junjiro R. Okajima
++
++
++0. Introduction
++----------------------------------------
++In the early days, aufs was entirely re-designed and re-implemented
++Unionfs Version 1.x series. Adding many original ideas, approaches,
++improvements and implementations, it becomes totally different from
++Unionfs while keeping the basic features.
++Recently, Unionfs Version 2.x series begin taking some of the same
++approaches to aufs1's.
++Unionfs is being developed by Professor Erez Zadok at Stony Brook
++University and his team.
++
++Aufs4 supports linux-4.0 and later, and for linux-3.x series try aufs3.
++If you want older kernel version support, try aufs2-2.6.git or
++aufs2-standalone.git repository, aufs1 from CVS on SourceForge.
++
++Note: it becomes clear that "Aufs was rejected. Let's give it up."
++      According to Christoph Hellwig, linux rejects all union-type
++      filesystems but UnionMount.
++<http://marc.info/?l=linux-kernel&m=123938533724484&w=2>
++
++PS. Al Viro seems have a plan to merge aufs as well as overlayfs and
++    UnionMount, and he pointed out an issue around a directory mutex
++    lock and aufs addressed it. But it is still unsure whether aufs will
++    be merged (or any other union solution).
++<http://marc.info/?l=linux-kernel&m=136312705029295&w=1>
++
++
++1. Features
++----------------------------------------
++- unite several directories into a single virtual filesystem. The member
++  directory is called as a branch.
++- you can specify the permission flags to the branch, which are 'readonly',
++  'readwrite' and 'whiteout-able.'
++- by upper writable branch, internal copyup and whiteout, files/dirs on
++  readonly branch are modifiable logically.
++- dynamic branch manipulation, add, del.
++- etc...
++
++Also there are many enhancements in aufs, such as:
++- test only the highest one for the directory permission (dirperm1)
++- copyup on open (coo=)
++- 'move' policy for copy-up between two writable branches, after
++  checking free space.
++- xattr, acl
++- readdir(3) in userspace.
++- keep inode number by external inode number table
++- keep the timestamps of file/dir in internal copyup operation
++- seekable directory, supporting NFS readdir.
++- whiteout is hardlinked in order to reduce the consumption of inodes
++  on branch
++- do not copyup, nor create a whiteout when it is unnecessary
++- revert a single systemcall when an error occurs in aufs
++- remount interface instead of ioctl
++- maintain /etc/mtab by an external command, /sbin/mount.aufs.
++- loopback mounted filesystem as a branch
++- kernel thread for removing the dir who has a plenty of whiteouts
++- support copyup sparse file (a file which has a 'hole' in it)
++- default permission flags for branches
++- selectable permission flags for ro branch, whether whiteout can
++  exist or not
++- export via NFS.
++- support <sysfs>/fs/aufs and <debugfs>/aufs.
++- support multiple writable branches, some policies to select one
++  among multiple writable branches.
++- a new semantics for link(2) and rename(2) to support multiple
++  writable branches.
++- no glibc changes are required.
++- pseudo hardlink (hardlink over branches)
++- allow a direct access manually to a file on branch, e.g. bypassing aufs.
++  including NFS or remote filesystem branch.
++- userspace wrapper for pathconf(3)/fpathconf(3) with _PC_LINK_MAX.
++- and more...
++
++Currently these features are dropped temporary from aufs4.
++See design/08plan.txt in detail.
++- nested mount, i.e. aufs as readonly no-whiteout branch of another aufs
++  (robr)
++- statistics of aufs thread (/sys/fs/aufs/stat)
++
++Features or just an idea in the future (see also design/*.txt),
++- reorder the branch index without del/re-add.
++- permanent xino files for NFSD
++- an option for refreshing the opened files after add/del branches
++- light version, without branch manipulation. (unnecessary?)
++- copyup in userspace
++- inotify in userspace
++- readv/writev
++
++
++2. Download
++----------------------------------------
++There are three GIT trees for aufs4, aufs4-linux.git,
++aufs4-standalone.git, and aufs-util.git. Note that there is no "4" in
++"aufs-util.git."
++While the aufs-util is always necessary, you need either of aufs4-linux
++or aufs4-standalone.
++
++The aufs4-linux tree includes the whole linux mainline GIT tree,
++git://git.kernel.org/.../torvalds/linux.git.
++And you cannot select CONFIG_AUFS_FS=m for this version, eg. you cannot
++build aufs4 as an external kernel module.
++Several extra patches are not included in this tree. Only
++aufs4-standalone tree contains them. They are describe in the later
++section "Configuration and Compilation."
++
++On the other hand, the aufs4-standalone tree has only aufs source files
++and necessary patches, and you can select CONFIG_AUFS_FS=m.
++But you need to apply all aufs patches manually.
++
++You will find GIT branches whose name is in form of "aufs4.x" where "x"
++represents the linux kernel version, "linux-4.x". For instance,
++"aufs4.0" is for linux-4.0. For latest "linux-4.x-rcN", use
++"aufs4.x-rcN" branch.
++
++o aufs4-linux tree
++$ git clone --reference /your/linux/git/tree \
++	git://github.com/sfjro/aufs4-linux.git aufs4-linux.git
++- if you don't have linux GIT tree, then remove "--reference ..."
++$ cd aufs4-linux.git
++$ git checkout origin/aufs4.0
++
++Or You may want to directly git-pull aufs into your linux GIT tree, and
++leave the patch-work to GIT.
++$ cd /your/linux/git/tree
++$ git remote add aufs4 git://github.com/sfjro/aufs4-linux.git
++$ git fetch aufs4
++$ git checkout -b my4.0 v4.0
++$ (add your local change...)
++$ git pull aufs4 aufs4.0
++- now you have v4.0 + your_changes + aufs4.0 in you my4.0 branch.
++- you may need to solve some conflicts between your_changes and
++  aufs4.0. in this case, git-rerere is recommended so that you can
++  solve the similar conflicts automatically when you upgrade to 4.1 or
++  later in the future.
++
++o aufs4-standalone tree
++$ git clone git://github.com/sfjro/aufs4-standalone.git aufs4-standalone.git
++$ cd aufs4-standalone.git
++$ git checkout origin/aufs4.0
++
++o aufs-util tree
++$ git clone git://git.code.sf.net/p/aufs/aufs-util aufs-util.git
++- note that the public aufs-util.git is on SourceForge instead of
++  GitHUB.
++$ cd aufs-util.git
++$ git checkout origin/aufs4.0
++
++Note: The 4.x-rcN branch is to be used with `rc' kernel versions ONLY.
++The minor version number, 'x' in '4.x', of aufs may not always
++follow the minor version number of the kernel.
++Because changes in the kernel that cause the use of a new
++minor version number do not always require changes to aufs-util.
++
++Since aufs-util has its own minor version number, you may not be
++able to find a GIT branch in aufs-util for your kernel's
++exact minor version number.
++In this case, you should git-checkout the branch for the
++nearest lower number.
++
++For (an unreleased) example:
++If you are using "linux-4.10" and the "aufs4.10" branch
++does not exist in aufs-util repository, then "aufs4.9", "aufs4.8"
++or something numerically smaller is the branch for your kernel.
++
++Also you can view all branches by
++	$ git branch -a
++
++
++3. Configuration and Compilation
++----------------------------------------
++Make sure you have git-checkout'ed the correct branch.
++
++For aufs4-linux tree,
++- enable CONFIG_AUFS_FS.
++- set other aufs configurations if necessary.
++
++For aufs4-standalone tree,
++There are several ways to build.
++
++1.
++- apply ./aufs4-kbuild.patch to your kernel source files.
++- apply ./aufs4-base.patch too.
++- apply ./aufs4-mmap.patch too.
++- apply ./aufs4-standalone.patch too, if you have a plan to set
++  CONFIG_AUFS_FS=m. otherwise you don't need ./aufs4-standalone.patch.
++- copy ./{Documentation,fs,include/uapi/linux/aufs_type.h} files to your
++  kernel source tree. Never copy $PWD/include/uapi/linux/Kbuild.
++- enable CONFIG_AUFS_FS, you can select either
++  =m or =y.
++- and build your kernel as usual.
++- install the built kernel.
++  Note: Since linux-3.9, every filesystem module requires an alias
++  "fs-<fsname>". You should make sure that "fs-aufs" is listed in your
++  modules.aliases file if you set CONFIG_AUFS_FS=m.
++- install the header files too by "make headers_install" to the
++  directory where you specify. By default, it is $PWD/usr.
++  "make help" shows a brief note for headers_install.
++- and reboot your system.
++
++2.
++- module only (CONFIG_AUFS_FS=m).
++- apply ./aufs4-base.patch to your kernel source files.
++- apply ./aufs4-mmap.patch too.
++- apply ./aufs4-standalone.patch too.
++- build your kernel, don't forget "make headers_install", and reboot.
++- edit ./config.mk and set other aufs configurations if necessary.
++  Note: You should read $PWD/fs/aufs/Kconfig carefully which describes
++  every aufs configurations.
++- build the module by simple "make".
++  Note: Since linux-3.9, every filesystem module requires an alias
++  "fs-<fsname>". You should make sure that "fs-aufs" is listed in your
++  modules.aliases file.
++- you can specify ${KDIR} make variable which points to your kernel
++  source tree.
++- install the files
++  + run "make install" to install the aufs module, or copy the built
++    $PWD/aufs.ko to /lib/modules/... and run depmod -a (or reboot simply).
++  + run "make install_headers" (instead of headers_install) to install
++    the modified aufs header file (you can specify DESTDIR which is
++    available in aufs standalone version's Makefile only), or copy
++    $PWD/usr/include/linux/aufs_type.h to /usr/include/linux or wherever
++    you like manually. By default, the target directory is $PWD/usr.
++- no need to apply aufs4-kbuild.patch, nor copying source files to your
++  kernel source tree.
++
++Note: The header file aufs_type.h is necessary to build aufs-util
++      as well as "make headers_install" in the kernel source tree.
++      headers_install is subject to be forgotten, but it is essentially
++      necessary, not only for building aufs-util.
++      You may not meet problems without headers_install in some older
++      version though.
++
++And then,
++- read README in aufs-util, build and install it
++- note that your distribution may contain an obsoleted version of
++  aufs_type.h in /usr/include/linux or something. When you build aufs
++  utilities, make sure that your compiler refers the correct aufs header
++  file which is built by "make headers_install."
++- if you want to use readdir(3) in userspace or pathconf(3) wrapper,
++  then run "make install_ulib" too. And refer to the aufs manual in
++  detail.
++
++There several other patches in aufs4-standalone.git. They are all
++optional. When you meet some problems, they will help you.
++- aufs4-loopback.patch
++  Supports a nested loopback mount in a branch-fs. This patch is
++  unnecessary until aufs produces a message like "you may want to try
++  another patch for loopback file".
++- vfs-ino.patch
++  Modifies a system global kernel internal function get_next_ino() in
++  order to stop assigning 0 for an inode-number. Not directly related to
++  aufs, but recommended generally.
++- tmpfs-idr.patch
++  Keeps the tmpfs inode number as the lowest value. Effective to reduce
++  the size of aufs XINO files for tmpfs branch. Also it prevents the
++  duplication of inode number, which is important for backup tools and
++  other utilities. When you find aufs XINO files for tmpfs branch
++  growing too much, try this patch.
++
++
++4. Usage
++----------------------------------------
++At first, make sure aufs-util are installed, and please read the aufs
++manual, aufs.5 in aufs-util.git tree.
++$ man -l aufs.5
++
++And then,
++$ mkdir /tmp/rw /tmp/aufs
++# mount -t aufs -o br=/tmp/rw:${HOME} none /tmp/aufs
++
++Here is another example. The result is equivalent.
++# mount -t aufs -o br=/tmp/rw=rw:${HOME}=ro none /tmp/aufs
++  Or
++# mount -t aufs -o br:/tmp/rw none /tmp/aufs
++# mount -o remount,append:${HOME} /tmp/aufs
++
++Then, you can see whole tree of your home dir through /tmp/aufs. If
++you modify a file under /tmp/aufs, the one on your home directory is
++not affected, instead the same named file will be newly created under
++/tmp/rw. And all of your modification to a file will be applied to
++the one under /tmp/rw. This is called the file based Copy on Write
++(COW) method.
++Aufs mount options are described in aufs.5.
++If you run chroot or something and make your aufs as a root directory,
++then you need to customize the shutdown script. See the aufs manual in
++detail.
++
++Additionally, there are some sample usages of aufs which are a
++diskless system with network booting, and LiveCD over NFS.
++See sample dir in CVS tree on SourceForge.
++
++
++5. Contact
++----------------------------------------
++When you have any problems or strange behaviour in aufs, please let me
++know with:
++- /proc/mounts (instead of the output of mount(8))
++- /sys/module/aufs/*
++- /sys/fs/aufs/* (if you have them)
++- /debug/aufs/* (if you have them)
++- linux kernel version
++  if your kernel is not plain, for example modified by distributor,
++  the url where i can download its source is necessary too.
++- aufs version which was printed at loading the module or booting the
++  system, instead of the date you downloaded.
++- configuration (define/undefine CONFIG_AUFS_xxx)
++- kernel configuration or /proc/config.gz (if you have it)
++- behaviour which you think to be incorrect
++- actual operation, reproducible one is better
++- mailto: aufs-users at lists.sourceforge.net
++
++Usually, I don't watch the Public Areas(Bugs, Support Requests, Patches,
++and Feature Requests) on SourceForge. Please join and write to
++aufs-users ML.
++
++
++6. Acknowledgements
++----------------------------------------
++Thanks to everyone who have tried and are using aufs, whoever
++have reported a bug or any feedback.
++
++Especially donators:
++Tomas Matejicek(slax.org) made a donation (much more than once).
++	Since Apr 2010, Tomas M (the author of Slax and Linux Live
++	scripts) is making "doubling" donations.
++	Unfortunately I cannot list all of the donators, but I really
++	appreciate.
++	It ends Aug 2010, but the ordinary donation URL is still available.
++	<http://sourceforge.net/donate/index.php?group_id=167503>
++Dai Itasaka made a donation (2007/8).
++Chuck Smith made a donation (2008/4, 10 and 12).
++Henk Schoneveld made a donation (2008/9).
++Chih-Wei Huang, ASUS, CTC donated Eee PC 4G (2008/10).
++Francois Dupoux made a donation (2008/11).
++Bruno Cesar Ribas and Luis Carlos Erpen de Bona, C3SL serves public
++	aufs2 GIT tree (2009/2).
++William Grant made a donation (2009/3).
++Patrick Lane made a donation (2009/4).
++The Mail Archive (mail-archive.com) made donations (2009/5).
++Nippy Networks (Ed Wildgoose) made a donation (2009/7).
++New Dream Network, LLC (www.dreamhost.com) made a donation (2009/11).
++Pavel Pronskiy made a donation (2011/2).
++Iridium and Inmarsat satellite phone retailer (www.mailasail.com), Nippy
++	Networks (Ed Wildgoose) made a donation for hardware (2011/3).
++Max Lekomcev (DOM-TV project) made a donation (2011/7, 12, 2012/3, 6 and
++11).
++Sam Liddicott made a donation (2011/9).
++Era Scarecrow made a donation (2013/4).
++Bor Ratajc made a donation (2013/4).
++Alessandro Gorreta made a donation (2013/4).
++POIRETTE Marc made a donation (2013/4).
++Alessandro Gorreta made a donation (2013/4).
++lauri kasvandik made a donation (2013/5).
++"pemasu from Finland" made a donation (2013/7).
++The Parted Magic Project made a donation (2013/9 and 11).
++Pavel Barta made a donation (2013/10).
++Nikolay Pertsev made a donation (2014/5).
++James B made a donation (2014/7).
++Stefano Di Biase made a donation (2014/8).
++Daniel Epellei made a donation (2015/1).
++
++Thank you very much.
++Donations are always, including future donations, very important and
++helpful for me to keep on developing aufs.
++
++
++7.
++----------------------------------------
++If you are an experienced user, no explanation is needed. Aufs is
++just a linux filesystem.
++
++
++Enjoy!
++
++# Local variables: ;
++# mode: text;
++# End: ;
+diff -Nur linux-4.0.4.orig/drivers/block/loop.c linux-4.0.4/drivers/block/loop.c
+--- linux-4.0.4.orig/drivers/block/loop.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/drivers/block/loop.c	2015-05-30 22:11:30.000000000 +0200
+@@ -592,6 +592,24 @@
+ 	return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR;
+ }
+ 
++/*
++ * for AUFS
++ * no get/put for file.
++ */
++struct file *loop_backing_file(struct super_block *sb)
++{
++	struct file *ret;
++	struct loop_device *l;
++
++	ret = NULL;
++	if (MAJOR(sb->s_dev) == LOOP_MAJOR) {
++		l = sb->s_bdev->bd_disk->private_data;
++		ret = l->lo_backing_file;
++	}
++	return ret;
++}
++EXPORT_SYMBOL(loop_backing_file);
++
+ /* loop sysfs attributes */
+ 
+ static ssize_t loop_attr_show(struct device *dev, char *page,
+diff -Nur linux-4.0.4.orig/fs/aufs/aufs.h linux-4.0.4/fs/aufs/aufs.h
+--- linux-4.0.4.orig/fs/aufs/aufs.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/aufs.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,46 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * all header files
++ */
++
++#ifndef __AUFS_H__
++#define __AUFS_H__
++
++#ifdef __KERNEL__
++
++#define AuStub(type, name, body, ...) \
++	static inline type name(__VA_ARGS__) { body; }
++
++#define AuStubVoid(name, ...) \
++	AuStub(void, name, , __VA_ARGS__)
++#define AuStubInt0(name, ...) \
++	AuStub(int, name, return 0, __VA_ARGS__)
++
++#include "debug.h"
++
++#include "branch.h"
++#include "cpup.h"
++#include "dcsub.h"
++#include "dbgaufs.h"
++#include "dentry.h"
++#include "dir.h"
++#include "dynop.h"
++#include "file.h"
++#include "fstype.h"
++#include "inode.h"
++#include "loop.h"
++#include "module.h"
++#include "opts.h"
++#include "rwsem.h"
++#include "spl.h"
++#include "super.h"
++#include "sysaufs.h"
++#include "vfsub.h"
++#include "whout.h"
++#include "wkq.h"
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/branch.c linux-4.0.4/fs/aufs/branch.c
+--- linux-4.0.4.orig/fs/aufs/branch.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/branch.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,1393 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * branch management
++ */
++
++#include <linux/compat.h>
++#include <linux/statfs.h>
++#include "aufs.h"
++
++/*
++ * free a single branch
++ */
++static void au_br_do_free(struct au_branch *br)
++{
++	int i;
++	struct au_wbr *wbr;
++	struct au_dykey **key;
++
++	au_hnotify_fin_br(br);
++
++	if (br->br_xino.xi_file)
++		fput(br->br_xino.xi_file);
++	mutex_destroy(&br->br_xino.xi_nondir_mtx);
++
++	AuDebugOn(atomic_read(&br->br_count));
++
++	wbr = br->br_wbr;
++	if (wbr) {
++		for (i = 0; i < AuBrWh_Last; i++)
++			dput(wbr->wbr_wh[i]);
++		AuDebugOn(atomic_read(&wbr->wbr_wh_running));
++		AuRwDestroy(&wbr->wbr_wh_rwsem);
++	}
++
++	if (br->br_fhsm) {
++		au_br_fhsm_fin(br->br_fhsm);
++		kfree(br->br_fhsm);
++	}
++
++	key = br->br_dykey;
++	for (i = 0; i < AuBrDynOp; i++, key++)
++		if (*key)
++			au_dy_put(*key);
++		else
++			break;
++
++	/* recursive lock, s_umount of branch's */
++	lockdep_off();
++	path_put(&br->br_path);
++	lockdep_on();
++	kfree(wbr);
++	kfree(br);
++}
++
++/*
++ * frees all branches
++ */
++void au_br_free(struct au_sbinfo *sbinfo)
++{
++	aufs_bindex_t bmax;
++	struct au_branch **br;
++
++	AuRwMustWriteLock(&sbinfo->si_rwsem);
++
++	bmax = sbinfo->si_bend + 1;
++	br = sbinfo->si_branch;
++	while (bmax--)
++		au_br_do_free(*br++);
++}
++
++/*
++ * find the index of a branch which is specified by @br_id.
++ */
++int au_br_index(struct super_block *sb, aufs_bindex_t br_id)
++{
++	aufs_bindex_t bindex, bend;
++
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++)
++		if (au_sbr_id(sb, bindex) == br_id)
++			return bindex;
++	return -1;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * add a branch
++ */
++
++static int test_overlap(struct super_block *sb, struct dentry *h_adding,
++			struct dentry *h_root)
++{
++	if (unlikely(h_adding == h_root
++		     || au_test_loopback_overlap(sb, h_adding)))
++		return 1;
++	if (h_adding->d_sb != h_root->d_sb)
++		return 0;
++	return au_test_subdir(h_adding, h_root)
++		|| au_test_subdir(h_root, h_adding);
++}
++
++/*
++ * returns a newly allocated branch. @new_nbranch is a number of branches
++ * after adding a branch.
++ */
++static struct au_branch *au_br_alloc(struct super_block *sb, int new_nbranch,
++				     int perm)
++{
++	struct au_branch *add_branch;
++	struct dentry *root;
++	int err;
++
++	err = -ENOMEM;
++	root = sb->s_root;
++	add_branch = kmalloc(sizeof(*add_branch), GFP_NOFS);
++	if (unlikely(!add_branch))
++		goto out;
++
++	err = au_hnotify_init_br(add_branch, perm);
++	if (unlikely(err))
++		goto out_br;
++
++	add_branch->br_wbr = NULL;
++	if (au_br_writable(perm)) {
++		/* may be freed separately at changing the branch permission */
++		add_branch->br_wbr = kmalloc(sizeof(*add_branch->br_wbr),
++					     GFP_NOFS);
++		if (unlikely(!add_branch->br_wbr))
++			goto out_hnotify;
++	}
++
++	add_branch->br_fhsm = NULL;
++	if (au_br_fhsm(perm)) {
++		err = au_fhsm_br_alloc(add_branch);
++		if (unlikely(err))
++			goto out_wbr;
++	}
++
++	err = au_sbr_realloc(au_sbi(sb), new_nbranch);
++	if (!err)
++		err = au_di_realloc(au_di(root), new_nbranch);
++	if (!err)
++		err = au_ii_realloc(au_ii(root->d_inode), new_nbranch);
++	if (!err)
++		return add_branch; /* success */
++
++out_wbr:
++	kfree(add_branch->br_wbr);
++out_hnotify:
++	au_hnotify_fin_br(add_branch);
++out_br:
++	kfree(add_branch);
++out:
++	return ERR_PTR(err);
++}
++
++/*
++ * test if the branch permission is legal or not.
++ */
++static int test_br(struct inode *inode, int brperm, char *path)
++{
++	int err;
++
++	err = (au_br_writable(brperm) && IS_RDONLY(inode));
++	if (!err)
++		goto out;
++
++	err = -EINVAL;
++	pr_err("write permission for readonly mount or inode, %s\n", path);
++
++out:
++	return err;
++}
++
++/*
++ * returns:
++ * 0: success, the caller will add it
++ * plus: success, it is already unified, the caller should ignore it
++ * minus: error
++ */
++static int test_add(struct super_block *sb, struct au_opt_add *add, int remount)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct dentry *root;
++	struct inode *inode, *h_inode;
++
++	root = sb->s_root;
++	bend = au_sbend(sb);
++	if (unlikely(bend >= 0
++		     && au_find_dbindex(root, add->path.dentry) >= 0)) {
++		err = 1;
++		if (!remount) {
++			err = -EINVAL;
++			pr_err("%s duplicated\n", add->pathname);
++		}
++		goto out;
++	}
++
++	err = -ENOSPC; /* -E2BIG; */
++	if (unlikely(AUFS_BRANCH_MAX <= add->bindex
++		     || AUFS_BRANCH_MAX - 1 <= bend)) {
++		pr_err("number of branches exceeded %s\n", add->pathname);
++		goto out;
++	}
++
++	err = -EDOM;
++	if (unlikely(add->bindex < 0 || bend + 1 < add->bindex)) {
++		pr_err("bad index %d\n", add->bindex);
++		goto out;
++	}
++
++	inode = add->path.dentry->d_inode;
++	err = -ENOENT;
++	if (unlikely(!inode->i_nlink)) {
++		pr_err("no existence %s\n", add->pathname);
++		goto out;
++	}
++
++	err = -EINVAL;
++	if (unlikely(inode->i_sb == sb)) {
++		pr_err("%s must be outside\n", add->pathname);
++		goto out;
++	}
++
++	if (unlikely(au_test_fs_unsuppoted(inode->i_sb))) {
++		pr_err("unsupported filesystem, %s (%s)\n",
++		       add->pathname, au_sbtype(inode->i_sb));
++		goto out;
++	}
++
++	if (unlikely(inode->i_sb->s_stack_depth)) {
++		pr_err("already stacked, %s (%s)\n",
++		       add->pathname, au_sbtype(inode->i_sb));
++		goto out;
++	}
++
++	err = test_br(add->path.dentry->d_inode, add->perm, add->pathname);
++	if (unlikely(err))
++		goto out;
++
++	if (bend < 0)
++		return 0; /* success */
++
++	err = -EINVAL;
++	for (bindex = 0; bindex <= bend; bindex++)
++		if (unlikely(test_overlap(sb, add->path.dentry,
++					  au_h_dptr(root, bindex)))) {
++			pr_err("%s is overlapped\n", add->pathname);
++			goto out;
++		}
++
++	err = 0;
++	if (au_opt_test(au_mntflags(sb), WARN_PERM)) {
++		h_inode = au_h_dptr(root, 0)->d_inode;
++		if ((h_inode->i_mode & S_IALLUGO) != (inode->i_mode & S_IALLUGO)
++		    || !uid_eq(h_inode->i_uid, inode->i_uid)
++		    || !gid_eq(h_inode->i_gid, inode->i_gid))
++			pr_warn("uid/gid/perm %s %u/%u/0%o, %u/%u/0%o\n",
++				add->pathname,
++				i_uid_read(inode), i_gid_read(inode),
++				(inode->i_mode & S_IALLUGO),
++				i_uid_read(h_inode), i_gid_read(h_inode),
++				(h_inode->i_mode & S_IALLUGO));
++	}
++
++out:
++	return err;
++}
++
++/*
++ * initialize or clean the whiteouts for an adding branch
++ */
++static int au_br_init_wh(struct super_block *sb, struct au_branch *br,
++			 int new_perm)
++{
++	int err, old_perm;
++	aufs_bindex_t bindex;
++	struct mutex *h_mtx;
++	struct au_wbr *wbr;
++	struct au_hinode *hdir;
++
++	err = vfsub_mnt_want_write(au_br_mnt(br));
++	if (unlikely(err))
++		goto out;
++
++	wbr = br->br_wbr;
++	old_perm = br->br_perm;
++	br->br_perm = new_perm;
++	hdir = NULL;
++	h_mtx = NULL;
++	bindex = au_br_index(sb, br->br_id);
++	if (0 <= bindex) {
++		hdir = au_hi(sb->s_root->d_inode, bindex);
++		au_hn_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++	} else {
++		h_mtx = &au_br_dentry(br)->d_inode->i_mutex;
++		mutex_lock_nested(h_mtx, AuLsc_I_PARENT);
++	}
++	if (!wbr)
++		err = au_wh_init(br, sb);
++	else {
++		wbr_wh_write_lock(wbr);
++		err = au_wh_init(br, sb);
++		wbr_wh_write_unlock(wbr);
++	}
++	if (hdir)
++		au_hn_imtx_unlock(hdir);
++	else
++		mutex_unlock(h_mtx);
++	vfsub_mnt_drop_write(au_br_mnt(br));
++	br->br_perm = old_perm;
++
++	if (!err && wbr && !au_br_writable(new_perm)) {
++		kfree(wbr);
++		br->br_wbr = NULL;
++	}
++
++out:
++	return err;
++}
++
++static int au_wbr_init(struct au_branch *br, struct super_block *sb,
++		       int perm)
++{
++	int err;
++	struct kstatfs kst;
++	struct au_wbr *wbr;
++
++	wbr = br->br_wbr;
++	au_rw_init(&wbr->wbr_wh_rwsem);
++	memset(wbr->wbr_wh, 0, sizeof(wbr->wbr_wh));
++	atomic_set(&wbr->wbr_wh_running, 0);
++	wbr->wbr_bytes = 0;
++
++	/*
++	 * a limit for rmdir/rename a dir
++	 * cf. AUFS_MAX_NAMELEN in include/uapi/linux/aufs_type.h
++	 */
++	err = vfs_statfs(&br->br_path, &kst);
++	if (unlikely(err))
++		goto out;
++	err = -EINVAL;
++	if (kst.f_namelen >= NAME_MAX)
++		err = au_br_init_wh(sb, br, perm);
++	else
++		pr_err("%pd(%s), unsupported namelen %ld\n",
++		       au_br_dentry(br),
++		       au_sbtype(au_br_dentry(br)->d_sb), kst.f_namelen);
++
++out:
++	return err;
++}
++
++/* initialize a new branch */
++static int au_br_init(struct au_branch *br, struct super_block *sb,
++		      struct au_opt_add *add)
++{
++	int err;
++
++	err = 0;
++	memset(&br->br_xino, 0, sizeof(br->br_xino));
++	mutex_init(&br->br_xino.xi_nondir_mtx);
++	br->br_perm = add->perm;
++	br->br_path = add->path; /* set first, path_get() later */
++	spin_lock_init(&br->br_dykey_lock);
++	memset(br->br_dykey, 0, sizeof(br->br_dykey));
++	atomic_set(&br->br_count, 0);
++	atomic_set(&br->br_xino_running, 0);
++	br->br_id = au_new_br_id(sb);
++	AuDebugOn(br->br_id < 0);
++
++	if (au_br_writable(add->perm)) {
++		err = au_wbr_init(br, sb, add->perm);
++		if (unlikely(err))
++			goto out_err;
++	}
++
++	if (au_opt_test(au_mntflags(sb), XINO)) {
++		err = au_xino_br(sb, br, add->path.dentry->d_inode->i_ino,
++				 au_sbr(sb, 0)->br_xino.xi_file, /*do_test*/1);
++		if (unlikely(err)) {
++			AuDebugOn(br->br_xino.xi_file);
++			goto out_err;
++		}
++	}
++
++	sysaufs_br_init(br);
++	path_get(&br->br_path);
++	goto out; /* success */
++
++out_err:
++	memset(&br->br_path, 0, sizeof(br->br_path));
++out:
++	return err;
++}
++
++static void au_br_do_add_brp(struct au_sbinfo *sbinfo, aufs_bindex_t bindex,
++			     struct au_branch *br, aufs_bindex_t bend,
++			     aufs_bindex_t amount)
++{
++	struct au_branch **brp;
++
++	AuRwMustWriteLock(&sbinfo->si_rwsem);
++
++	brp = sbinfo->si_branch + bindex;
++	memmove(brp + 1, brp, sizeof(*brp) * amount);
++	*brp = br;
++	sbinfo->si_bend++;
++	if (unlikely(bend < 0))
++		sbinfo->si_bend = 0;
++}
++
++static void au_br_do_add_hdp(struct au_dinfo *dinfo, aufs_bindex_t bindex,
++			     aufs_bindex_t bend, aufs_bindex_t amount)
++{
++	struct au_hdentry *hdp;
++
++	AuRwMustWriteLock(&dinfo->di_rwsem);
++
++	hdp = dinfo->di_hdentry + bindex;
++	memmove(hdp + 1, hdp, sizeof(*hdp) * amount);
++	au_h_dentry_init(hdp);
++	dinfo->di_bend++;
++	if (unlikely(bend < 0))
++		dinfo->di_bstart = 0;
++}
++
++static void au_br_do_add_hip(struct au_iinfo *iinfo, aufs_bindex_t bindex,
++			     aufs_bindex_t bend, aufs_bindex_t amount)
++{
++	struct au_hinode *hip;
++
++	AuRwMustWriteLock(&iinfo->ii_rwsem);
++
++	hip = iinfo->ii_hinode + bindex;
++	memmove(hip + 1, hip, sizeof(*hip) * amount);
++	hip->hi_inode = NULL;
++	au_hn_init(hip);
++	iinfo->ii_bend++;
++	if (unlikely(bend < 0))
++		iinfo->ii_bstart = 0;
++}
++
++static void au_br_do_add(struct super_block *sb, struct au_branch *br,
++			 aufs_bindex_t bindex)
++{
++	struct dentry *root, *h_dentry;
++	struct inode *root_inode;
++	aufs_bindex_t bend, amount;
++
++	root = sb->s_root;
++	root_inode = root->d_inode;
++	bend = au_sbend(sb);
++	amount = bend + 1 - bindex;
++	h_dentry = au_br_dentry(br);
++	au_sbilist_lock();
++	au_br_do_add_brp(au_sbi(sb), bindex, br, bend, amount);
++	au_br_do_add_hdp(au_di(root), bindex, bend, amount);
++	au_br_do_add_hip(au_ii(root_inode), bindex, bend, amount);
++	au_set_h_dptr(root, bindex, dget(h_dentry));
++	au_set_h_iptr(root_inode, bindex, au_igrab(h_dentry->d_inode),
++		      /*flags*/0);
++	au_sbilist_unlock();
++}
++
++int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount)
++{
++	int err;
++	aufs_bindex_t bend, add_bindex;
++	struct dentry *root, *h_dentry;
++	struct inode *root_inode;
++	struct au_branch *add_branch;
++
++	root = sb->s_root;
++	root_inode = root->d_inode;
++	IMustLock(root_inode);
++	err = test_add(sb, add, remount);
++	if (unlikely(err < 0))
++		goto out;
++	if (err) {
++		err = 0;
++		goto out; /* success */
++	}
++
++	bend = au_sbend(sb);
++	add_branch = au_br_alloc(sb, bend + 2, add->perm);
++	err = PTR_ERR(add_branch);
++	if (IS_ERR(add_branch))
++		goto out;
++
++	err = au_br_init(add_branch, sb, add);
++	if (unlikely(err)) {
++		au_br_do_free(add_branch);
++		goto out;
++	}
++
++	add_bindex = add->bindex;
++	if (!remount)
++		au_br_do_add(sb, add_branch, add_bindex);
++	else {
++		sysaufs_brs_del(sb, add_bindex);
++		au_br_do_add(sb, add_branch, add_bindex);
++		sysaufs_brs_add(sb, add_bindex);
++	}
++
++	h_dentry = add->path.dentry;
++	if (!add_bindex) {
++		au_cpup_attr_all(root_inode, /*force*/1);
++		sb->s_maxbytes = h_dentry->d_sb->s_maxbytes;
++	} else
++		au_add_nlink(root_inode, h_dentry->d_inode);
++
++	/*
++	 * this test/set prevents aufs from handling unnecesary notify events
++	 * of xino files, in case of re-adding a writable branch which was
++	 * once detached from aufs.
++	 */
++	if (au_xino_brid(sb) < 0
++	    && au_br_writable(add_branch->br_perm)
++	    && !au_test_fs_bad_xino(h_dentry->d_sb)
++	    && add_branch->br_xino.xi_file
++	    && add_branch->br_xino.xi_file->f_path.dentry->d_parent == h_dentry)
++		au_xino_brid_set(sb, add_branch->br_id);
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static unsigned long long au_farray_cb(void *a,
++				       unsigned long long max __maybe_unused,
++				       void *arg)
++{
++	unsigned long long n;
++	struct file **p, *f;
++	struct au_sphlhead *files;
++	struct au_finfo *finfo;
++	struct super_block *sb = arg;
++
++	n = 0;
++	p = a;
++	files = &au_sbi(sb)->si_files;
++	spin_lock(&files->spin);
++	hlist_for_each_entry(finfo, &files->head, fi_hlist) {
++		f = finfo->fi_file;
++		if (file_count(f)
++		    && !special_file(file_inode(f)->i_mode)) {
++			get_file(f);
++			*p++ = f;
++			n++;
++			AuDebugOn(n > max);
++		}
++	}
++	spin_unlock(&files->spin);
++
++	return n;
++}
++
++static struct file **au_farray_alloc(struct super_block *sb,
++				     unsigned long long *max)
++{
++	*max = atomic_long_read(&au_sbi(sb)->si_nfiles);
++	return au_array_alloc(max, au_farray_cb, sb);
++}
++
++static void au_farray_free(struct file **a, unsigned long long max)
++{
++	unsigned long long ull;
++
++	for (ull = 0; ull < max; ull++)
++		if (a[ull])
++			fput(a[ull]);
++	au_array_free(a);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * delete a branch
++ */
++
++/* to show the line number, do not make it inlined function */
++#define AuVerbose(do_info, fmt, ...) do { \
++	if (do_info) \
++		pr_info(fmt, ##__VA_ARGS__); \
++} while (0)
++
++static int au_test_ibusy(struct inode *inode, aufs_bindex_t bstart,
++			 aufs_bindex_t bend)
++{
++	return (inode && !S_ISDIR(inode->i_mode)) || bstart == bend;
++}
++
++static int au_test_dbusy(struct dentry *dentry, aufs_bindex_t bstart,
++			 aufs_bindex_t bend)
++{
++	return au_test_ibusy(dentry->d_inode, bstart, bend);
++}
++
++/*
++ * test if the branch is deletable or not.
++ */
++static int test_dentry_busy(struct dentry *root, aufs_bindex_t bindex,
++			    unsigned int sigen, const unsigned int verbose)
++{
++	int err, i, j, ndentry;
++	aufs_bindex_t bstart, bend;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry *d;
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	err = au_dcsub_pages(&dpages, root, NULL, NULL);
++	if (unlikely(err))
++		goto out_dpages;
++
++	for (i = 0; !err && i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		ndentry = dpage->ndentry;
++		for (j = 0; !err && j < ndentry; j++) {
++			d = dpage->dentries[j];
++			AuDebugOn(au_dcount(d) <= 0);
++			if (!au_digen_test(d, sigen)) {
++				di_read_lock_child(d, AuLock_IR);
++				if (unlikely(au_dbrange_test(d))) {
++					di_read_unlock(d, AuLock_IR);
++					continue;
++				}
++			} else {
++				di_write_lock_child(d);
++				if (unlikely(au_dbrange_test(d))) {
++					di_write_unlock(d);
++					continue;
++				}
++				err = au_reval_dpath(d, sigen);
++				if (!err)
++					di_downgrade_lock(d, AuLock_IR);
++				else {
++					di_write_unlock(d);
++					break;
++				}
++			}
++
++			/* AuDbgDentry(d); */
++			bstart = au_dbstart(d);
++			bend = au_dbend(d);
++			if (bstart <= bindex
++			    && bindex <= bend
++			    && au_h_dptr(d, bindex)
++			    && au_test_dbusy(d, bstart, bend)) {
++				err = -EBUSY;
++				AuVerbose(verbose, "busy %pd\n", d);
++				AuDbgDentry(d);
++			}
++			di_read_unlock(d, AuLock_IR);
++		}
++	}
++
++out_dpages:
++	au_dpages_free(&dpages);
++out:
++	return err;
++}
++
++static int test_inode_busy(struct super_block *sb, aufs_bindex_t bindex,
++			   unsigned int sigen, const unsigned int verbose)
++{
++	int err;
++	unsigned long long max, ull;
++	struct inode *i, **array;
++	aufs_bindex_t bstart, bend;
++
++	array = au_iarray_alloc(sb, &max);
++	err = PTR_ERR(array);
++	if (IS_ERR(array))
++		goto out;
++
++	err = 0;
++	AuDbg("b%d\n", bindex);
++	for (ull = 0; !err && ull < max; ull++) {
++		i = array[ull];
++		if (unlikely(!i))
++			break;
++		if (i->i_ino == AUFS_ROOT_INO)
++			continue;
++
++		/* AuDbgInode(i); */
++		if (au_iigen(i, NULL) == sigen)
++			ii_read_lock_child(i);
++		else {
++			ii_write_lock_child(i);
++			err = au_refresh_hinode_self(i);
++			au_iigen_dec(i);
++			if (!err)
++				ii_downgrade_lock(i);
++			else {
++				ii_write_unlock(i);
++				break;
++			}
++		}
++
++		bstart = au_ibstart(i);
++		bend = au_ibend(i);
++		if (bstart <= bindex
++		    && bindex <= bend
++		    && au_h_iptr(i, bindex)
++		    && au_test_ibusy(i, bstart, bend)) {
++			err = -EBUSY;
++			AuVerbose(verbose, "busy i%lu\n", i->i_ino);
++			AuDbgInode(i);
++		}
++		ii_read_unlock(i);
++	}
++	au_iarray_free(array, max);
++
++out:
++	return err;
++}
++
++static int test_children_busy(struct dentry *root, aufs_bindex_t bindex,
++			      const unsigned int verbose)
++{
++	int err;
++	unsigned int sigen;
++
++	sigen = au_sigen(root->d_sb);
++	DiMustNoWaiters(root);
++	IiMustNoWaiters(root->d_inode);
++	di_write_unlock(root);
++	err = test_dentry_busy(root, bindex, sigen, verbose);
++	if (!err)
++		err = test_inode_busy(root->d_sb, bindex, sigen, verbose);
++	di_write_lock_child(root); /* aufs_write_lock() calls ..._child() */
++
++	return err;
++}
++
++static int test_dir_busy(struct file *file, aufs_bindex_t br_id,
++			 struct file **to_free, int *idx)
++{
++	int err;
++	unsigned char matched, root;
++	aufs_bindex_t bindex, bend;
++	struct au_fidir *fidir;
++	struct au_hfile *hfile;
++
++	err = 0;
++	root = IS_ROOT(file->f_path.dentry);
++	if (root) {
++		get_file(file);
++		to_free[*idx] = file;
++		(*idx)++;
++		goto out;
++	}
++
++	matched = 0;
++	fidir = au_fi(file)->fi_hdir;
++	AuDebugOn(!fidir);
++	bend = au_fbend_dir(file);
++	for (bindex = au_fbstart(file); bindex <= bend; bindex++) {
++		hfile = fidir->fd_hfile + bindex;
++		if (!hfile->hf_file)
++			continue;
++
++		if (hfile->hf_br->br_id == br_id) {
++			matched = 1;
++			break;
++		}
++	}
++	if (matched)
++		err = -EBUSY;
++
++out:
++	return err;
++}
++
++static int test_file_busy(struct super_block *sb, aufs_bindex_t br_id,
++			  struct file **to_free, int opened)
++{
++	int err, idx;
++	unsigned long long ull, max;
++	aufs_bindex_t bstart;
++	struct file *file, **array;
++	struct dentry *root;
++	struct au_hfile *hfile;
++
++	array = au_farray_alloc(sb, &max);
++	err = PTR_ERR(array);
++	if (IS_ERR(array))
++		goto out;
++
++	err = 0;
++	idx = 0;
++	root = sb->s_root;
++	di_write_unlock(root);
++	for (ull = 0; ull < max; ull++) {
++		file = array[ull];
++		if (unlikely(!file))
++			break;
++
++		/* AuDbg("%pD\n", file); */
++		fi_read_lock(file);
++		bstart = au_fbstart(file);
++		if (!d_is_dir(file->f_path.dentry)) {
++			hfile = &au_fi(file)->fi_htop;
++			if (hfile->hf_br->br_id == br_id)
++				err = -EBUSY;
++		} else
++			err = test_dir_busy(file, br_id, to_free, &idx);
++		fi_read_unlock(file);
++		if (unlikely(err))
++			break;
++	}
++	di_write_lock_child(root);
++	au_farray_free(array, max);
++	AuDebugOn(idx > opened);
++
++out:
++	return err;
++}
++
++static void br_del_file(struct file **to_free, unsigned long long opened,
++			  aufs_bindex_t br_id)
++{
++	unsigned long long ull;
++	aufs_bindex_t bindex, bstart, bend, bfound;
++	struct file *file;
++	struct au_fidir *fidir;
++	struct au_hfile *hfile;
++
++	for (ull = 0; ull < opened; ull++) {
++		file = to_free[ull];
++		if (unlikely(!file))
++			break;
++
++		/* AuDbg("%pD\n", file); */
++		AuDebugOn(!d_is_dir(file->f_path.dentry));
++		bfound = -1;
++		fidir = au_fi(file)->fi_hdir;
++		AuDebugOn(!fidir);
++		fi_write_lock(file);
++		bstart = au_fbstart(file);
++		bend = au_fbend_dir(file);
++		for (bindex = bstart; bindex <= bend; bindex++) {
++			hfile = fidir->fd_hfile + bindex;
++			if (!hfile->hf_file)
++				continue;
++
++			if (hfile->hf_br->br_id == br_id) {
++				bfound = bindex;
++				break;
++			}
++		}
++		AuDebugOn(bfound < 0);
++		au_set_h_fptr(file, bfound, NULL);
++		if (bfound == bstart) {
++			for (bstart++; bstart <= bend; bstart++)
++				if (au_hf_dir(file, bstart)) {
++					au_set_fbstart(file, bstart);
++					break;
++				}
++		}
++		fi_write_unlock(file);
++	}
++}
++
++static void au_br_do_del_brp(struct au_sbinfo *sbinfo,
++			     const aufs_bindex_t bindex,
++			     const aufs_bindex_t bend)
++{
++	struct au_branch **brp, **p;
++
++	AuRwMustWriteLock(&sbinfo->si_rwsem);
++
++	brp = sbinfo->si_branch + bindex;
++	if (bindex < bend)
++		memmove(brp, brp + 1, sizeof(*brp) * (bend - bindex));
++	sbinfo->si_branch[0 + bend] = NULL;
++	sbinfo->si_bend--;
++
++	p = krealloc(sbinfo->si_branch, sizeof(*p) * bend, AuGFP_SBILIST);
++	if (p)
++		sbinfo->si_branch = p;
++	/* harmless error */
++}
++
++static void au_br_do_del_hdp(struct au_dinfo *dinfo, const aufs_bindex_t bindex,
++			     const aufs_bindex_t bend)
++{
++	struct au_hdentry *hdp, *p;
++
++	AuRwMustWriteLock(&dinfo->di_rwsem);
++
++	hdp = dinfo->di_hdentry;
++	if (bindex < bend)
++		memmove(hdp + bindex, hdp + bindex + 1,
++			sizeof(*hdp) * (bend - bindex));
++	hdp[0 + bend].hd_dentry = NULL;
++	dinfo->di_bend--;
++
++	p = krealloc(hdp, sizeof(*p) * bend, AuGFP_SBILIST);
++	if (p)
++		dinfo->di_hdentry = p;
++	/* harmless error */
++}
++
++static void au_br_do_del_hip(struct au_iinfo *iinfo, const aufs_bindex_t bindex,
++			     const aufs_bindex_t bend)
++{
++	struct au_hinode *hip, *p;
++
++	AuRwMustWriteLock(&iinfo->ii_rwsem);
++
++	hip = iinfo->ii_hinode + bindex;
++	if (bindex < bend)
++		memmove(hip, hip + 1, sizeof(*hip) * (bend - bindex));
++	iinfo->ii_hinode[0 + bend].hi_inode = NULL;
++	au_hn_init(iinfo->ii_hinode + bend);
++	iinfo->ii_bend--;
++
++	p = krealloc(iinfo->ii_hinode, sizeof(*p) * bend, AuGFP_SBILIST);
++	if (p)
++		iinfo->ii_hinode = p;
++	/* harmless error */
++}
++
++static void au_br_do_del(struct super_block *sb, aufs_bindex_t bindex,
++			 struct au_branch *br)
++{
++	aufs_bindex_t bend;
++	struct au_sbinfo *sbinfo;
++	struct dentry *root, *h_root;
++	struct inode *inode, *h_inode;
++	struct au_hinode *hinode;
++
++	SiMustWriteLock(sb);
++
++	root = sb->s_root;
++	inode = root->d_inode;
++	sbinfo = au_sbi(sb);
++	bend = sbinfo->si_bend;
++
++	h_root = au_h_dptr(root, bindex);
++	hinode = au_hi(inode, bindex);
++	h_inode = au_igrab(hinode->hi_inode);
++	au_hiput(hinode);
++
++	au_sbilist_lock();
++	au_br_do_del_brp(sbinfo, bindex, bend);
++	au_br_do_del_hdp(au_di(root), bindex, bend);
++	au_br_do_del_hip(au_ii(inode), bindex, bend);
++	au_sbilist_unlock();
++
++	dput(h_root);
++	iput(h_inode);
++	au_br_do_free(br);
++}
++
++static unsigned long long empty_cb(void *array, unsigned long long max,
++				   void *arg)
++{
++	return max;
++}
++
++int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
++{
++	int err, rerr, i;
++	unsigned long long opened;
++	unsigned int mnt_flags;
++	aufs_bindex_t bindex, bend, br_id;
++	unsigned char do_wh, verbose;
++	struct au_branch *br;
++	struct au_wbr *wbr;
++	struct dentry *root;
++	struct file **to_free;
++
++	err = 0;
++	opened = 0;
++	to_free = NULL;
++	root = sb->s_root;
++	bindex = au_find_dbindex(root, del->h_path.dentry);
++	if (bindex < 0) {
++		if (remount)
++			goto out; /* success */
++		err = -ENOENT;
++		pr_err("%s no such branch\n", del->pathname);
++		goto out;
++	}
++	AuDbg("bindex b%d\n", bindex);
++
++	err = -EBUSY;
++	mnt_flags = au_mntflags(sb);
++	verbose = !!au_opt_test(mnt_flags, VERBOSE);
++	bend = au_sbend(sb);
++	if (unlikely(!bend)) {
++		AuVerbose(verbose, "no more branches left\n");
++		goto out;
++	}
++	br = au_sbr(sb, bindex);
++	AuDebugOn(!path_equal(&br->br_path, &del->h_path));
++
++	br_id = br->br_id;
++	opened = atomic_read(&br->br_count);
++	if (unlikely(opened)) {
++		to_free = au_array_alloc(&opened, empty_cb, NULL);
++		err = PTR_ERR(to_free);
++		if (IS_ERR(to_free))
++			goto out;
++
++		err = test_file_busy(sb, br_id, to_free, opened);
++		if (unlikely(err)) {
++			AuVerbose(verbose, "%llu file(s) opened\n", opened);
++			goto out;
++		}
++	}
++
++	wbr = br->br_wbr;
++	do_wh = wbr && (wbr->wbr_whbase || wbr->wbr_plink || wbr->wbr_orph);
++	if (do_wh) {
++		/* instead of WbrWhMustWriteLock(wbr) */
++		SiMustWriteLock(sb);
++		for (i = 0; i < AuBrWh_Last; i++) {
++			dput(wbr->wbr_wh[i]);
++			wbr->wbr_wh[i] = NULL;
++		}
++	}
++
++	err = test_children_busy(root, bindex, verbose);
++	if (unlikely(err)) {
++		if (do_wh)
++			goto out_wh;
++		goto out;
++	}
++
++	err = 0;
++	if (to_free) {
++		/*
++		 * now we confirmed the branch is deletable.
++		 * let's free the remaining opened dirs on the branch.
++		 */
++		di_write_unlock(root);
++		br_del_file(to_free, opened, br_id);
++		di_write_lock_child(root);
++	}
++
++	if (!remount)
++		au_br_do_del(sb, bindex, br);
++	else {
++		sysaufs_brs_del(sb, bindex);
++		au_br_do_del(sb, bindex, br);
++		sysaufs_brs_add(sb, bindex);
++	}
++
++	if (!bindex) {
++		au_cpup_attr_all(root->d_inode, /*force*/1);
++		sb->s_maxbytes = au_sbr_sb(sb, 0)->s_maxbytes;
++	} else
++		au_sub_nlink(root->d_inode, del->h_path.dentry->d_inode);
++	if (au_opt_test(mnt_flags, PLINK))
++		au_plink_half_refresh(sb, br_id);
++
++	if (au_xino_brid(sb) == br_id)
++		au_xino_brid_set(sb, -1);
++	goto out; /* success */
++
++out_wh:
++	/* revert */
++	rerr = au_br_init_wh(sb, br, br->br_perm);
++	if (rerr)
++		pr_warn("failed re-creating base whiteout, %s. (%d)\n",
++			del->pathname, rerr);
++out:
++	if (to_free)
++		au_farray_free(to_free, opened);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_ibusy(struct super_block *sb, struct aufs_ibusy __user *arg)
++{
++	int err;
++	aufs_bindex_t bstart, bend;
++	struct aufs_ibusy ibusy;
++	struct inode *inode, *h_inode;
++
++	err = -EPERM;
++	if (unlikely(!capable(CAP_SYS_ADMIN)))
++		goto out;
++
++	err = copy_from_user(&ibusy, arg, sizeof(ibusy));
++	if (!err)
++		err = !access_ok(VERIFY_WRITE, &arg->h_ino, sizeof(arg->h_ino));
++	if (unlikely(err)) {
++		err = -EFAULT;
++		AuTraceErr(err);
++		goto out;
++	}
++
++	err = -EINVAL;
++	si_read_lock(sb, AuLock_FLUSH);
++	if (unlikely(ibusy.bindex < 0 || ibusy.bindex > au_sbend(sb)))
++		goto out_unlock;
++
++	err = 0;
++	ibusy.h_ino = 0; /* invalid */
++	inode = ilookup(sb, ibusy.ino);
++	if (!inode
++	    || inode->i_ino == AUFS_ROOT_INO
++	    || is_bad_inode(inode))
++		goto out_unlock;
++
++	ii_read_lock_child(inode);
++	bstart = au_ibstart(inode);
++	bend = au_ibend(inode);
++	if (bstart <= ibusy.bindex && ibusy.bindex <= bend) {
++		h_inode = au_h_iptr(inode, ibusy.bindex);
++		if (h_inode && au_test_ibusy(inode, bstart, bend))
++			ibusy.h_ino = h_inode->i_ino;
++	}
++	ii_read_unlock(inode);
++	iput(inode);
++
++out_unlock:
++	si_read_unlock(sb);
++	if (!err) {
++		err = __put_user(ibusy.h_ino, &arg->h_ino);
++		if (unlikely(err)) {
++			err = -EFAULT;
++			AuTraceErr(err);
++		}
++	}
++out:
++	return err;
++}
++
++long au_ibusy_ioctl(struct file *file, unsigned long arg)
++{
++	return au_ibusy(file->f_path.dentry->d_sb, (void __user *)arg);
++}
++
++#ifdef CONFIG_COMPAT
++long au_ibusy_compat_ioctl(struct file *file, unsigned long arg)
++{
++	return au_ibusy(file->f_path.dentry->d_sb, compat_ptr(arg));
++}
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * change a branch permission
++ */
++
++static void au_warn_ima(void)
++{
++#ifdef CONFIG_IMA
++	/* since it doesn't support mark_files_ro() */
++	AuWarn1("RW -> RO makes IMA to produce wrong message\n");
++#endif
++}
++
++static int do_need_sigen_inc(int a, int b)
++{
++	return au_br_whable(a) && !au_br_whable(b);
++}
++
++static int need_sigen_inc(int old, int new)
++{
++	return do_need_sigen_inc(old, new)
++		|| do_need_sigen_inc(new, old);
++}
++
++static int au_br_mod_files_ro(struct super_block *sb, aufs_bindex_t bindex)
++{
++	int err, do_warn;
++	unsigned int mnt_flags;
++	unsigned long long ull, max;
++	aufs_bindex_t br_id;
++	unsigned char verbose, writer;
++	struct file *file, *hf, **array;
++	struct au_hfile *hfile;
++
++	mnt_flags = au_mntflags(sb);
++	verbose = !!au_opt_test(mnt_flags, VERBOSE);
++
++	array = au_farray_alloc(sb, &max);
++	err = PTR_ERR(array);
++	if (IS_ERR(array))
++		goto out;
++
++	do_warn = 0;
++	br_id = au_sbr_id(sb, bindex);
++	for (ull = 0; ull < max; ull++) {
++		file = array[ull];
++		if (unlikely(!file))
++			break;
++
++		/* AuDbg("%pD\n", file); */
++		fi_read_lock(file);
++		if (unlikely(au_test_mmapped(file))) {
++			err = -EBUSY;
++			AuVerbose(verbose, "mmapped %pD\n", file);
++			AuDbgFile(file);
++			FiMustNoWaiters(file);
++			fi_read_unlock(file);
++			goto out_array;
++		}
++
++		hfile = &au_fi(file)->fi_htop;
++		hf = hfile->hf_file;
++		if (!d_is_reg(file->f_path.dentry)
++		    || !(file->f_mode & FMODE_WRITE)
++		    || hfile->hf_br->br_id != br_id
++		    || !(hf->f_mode & FMODE_WRITE))
++			array[ull] = NULL;
++		else {
++			do_warn = 1;
++			get_file(file);
++		}
++
++		FiMustNoWaiters(file);
++		fi_read_unlock(file);
++		fput(file);
++	}
++
++	err = 0;
++	if (do_warn)
++		au_warn_ima();
++
++	for (ull = 0; ull < max; ull++) {
++		file = array[ull];
++		if (!file)
++			continue;
++
++		/* todo: already flushed? */
++		/*
++		 * fs/super.c:mark_files_ro() is gone, but aufs keeps its
++		 * approach which resets f_mode and calls mnt_drop_write() and
++		 * file_release_write() for each file, because the branch
++		 * attribute in aufs world is totally different from the native
++		 * fs rw/ro mode.
++		*/
++		/* fi_read_lock(file); */
++		hfile = &au_fi(file)->fi_htop;
++		hf = hfile->hf_file;
++		/* fi_read_unlock(file); */
++		spin_lock(&hf->f_lock);
++		writer = !!(hf->f_mode & FMODE_WRITER);
++		hf->f_mode &= ~(FMODE_WRITE | FMODE_WRITER);
++		spin_unlock(&hf->f_lock);
++		if (writer) {
++			put_write_access(file_inode(hf));
++			__mnt_drop_write(hf->f_path.mnt);
++		}
++	}
++
++out_array:
++	au_farray_free(array, max);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
++	      int *do_refresh)
++{
++	int err, rerr;
++	aufs_bindex_t bindex;
++	struct dentry *root;
++	struct au_branch *br;
++	struct au_br_fhsm *bf;
++
++	root = sb->s_root;
++	bindex = au_find_dbindex(root, mod->h_root);
++	if (bindex < 0) {
++		if (remount)
++			return 0; /* success */
++		err = -ENOENT;
++		pr_err("%s no such branch\n", mod->path);
++		goto out;
++	}
++	AuDbg("bindex b%d\n", bindex);
++
++	err = test_br(mod->h_root->d_inode, mod->perm, mod->path);
++	if (unlikely(err))
++		goto out;
++
++	br = au_sbr(sb, bindex);
++	AuDebugOn(mod->h_root != au_br_dentry(br));
++	if (br->br_perm == mod->perm)
++		return 0; /* success */
++
++	/* pre-allocate for non-fhsm --> fhsm */
++	bf = NULL;
++	if (!au_br_fhsm(br->br_perm) && au_br_fhsm(mod->perm)) {
++		err = au_fhsm_br_alloc(br);
++		if (unlikely(err))
++			goto out;
++		bf = br->br_fhsm;
++		br->br_fhsm = NULL;
++	}
++
++	if (au_br_writable(br->br_perm)) {
++		/* remove whiteout base */
++		err = au_br_init_wh(sb, br, mod->perm);
++		if (unlikely(err))
++			goto out_bf;
++
++		if (!au_br_writable(mod->perm)) {
++			/* rw --> ro, file might be mmapped */
++			DiMustNoWaiters(root);
++			IiMustNoWaiters(root->d_inode);
++			di_write_unlock(root);
++			err = au_br_mod_files_ro(sb, bindex);
++			/* aufs_write_lock() calls ..._child() */
++			di_write_lock_child(root);
++
++			if (unlikely(err)) {
++				rerr = -ENOMEM;
++				br->br_wbr = kmalloc(sizeof(*br->br_wbr),
++						     GFP_NOFS);
++				if (br->br_wbr)
++					rerr = au_wbr_init(br, sb, br->br_perm);
++				if (unlikely(rerr)) {
++					AuIOErr("nested error %d (%d)\n",
++						rerr, err);
++					br->br_perm = mod->perm;
++				}
++			}
++		}
++	} else if (au_br_writable(mod->perm)) {
++		/* ro --> rw */
++		err = -ENOMEM;
++		br->br_wbr = kmalloc(sizeof(*br->br_wbr), GFP_NOFS);
++		if (br->br_wbr) {
++			err = au_wbr_init(br, sb, mod->perm);
++			if (unlikely(err)) {
++				kfree(br->br_wbr);
++				br->br_wbr = NULL;
++			}
++		}
++	}
++	if (unlikely(err))
++		goto out_bf;
++
++	if (au_br_fhsm(br->br_perm)) {
++		if (!au_br_fhsm(mod->perm)) {
++			/* fhsm --> non-fhsm */
++			au_br_fhsm_fin(br->br_fhsm);
++			kfree(br->br_fhsm);
++			br->br_fhsm = NULL;
++		}
++	} else if (au_br_fhsm(mod->perm))
++		/* non-fhsm --> fhsm */
++		br->br_fhsm = bf;
++
++	*do_refresh |= need_sigen_inc(br->br_perm, mod->perm);
++	br->br_perm = mod->perm;
++	goto out; /* success */
++
++out_bf:
++	kfree(bf);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_br_stfs(struct au_branch *br, struct aufs_stfs *stfs)
++{
++	int err;
++	struct kstatfs kstfs;
++
++	err = vfs_statfs(&br->br_path, &kstfs);
++	if (!err) {
++		stfs->f_blocks = kstfs.f_blocks;
++		stfs->f_bavail = kstfs.f_bavail;
++		stfs->f_files = kstfs.f_files;
++		stfs->f_ffree = kstfs.f_ffree;
++	}
++
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/branch.h linux-4.0.4/fs/aufs/branch.h
+--- linux-4.0.4.orig/fs/aufs/branch.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/branch.h	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,266 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * branch filesystems and xino for them
++ */
++
++#ifndef __AUFS_BRANCH_H__
++#define __AUFS_BRANCH_H__
++
++#ifdef __KERNEL__
++
++#include <linux/mount.h>
++#include "dynop.h"
++#include "rwsem.h"
++#include "super.h"
++
++/* ---------------------------------------------------------------------- */
++
++/* a xino file */
++struct au_xino_file {
++	struct file		*xi_file;
++	struct mutex		xi_nondir_mtx;
++
++	/* todo: make xino files an array to support huge inode number */
++
++#ifdef CONFIG_DEBUG_FS
++	struct dentry		 *xi_dbgaufs;
++#endif
++};
++
++/* File-based Hierarchical Storage Management */
++struct au_br_fhsm {
++#ifdef CONFIG_AUFS_FHSM
++	struct mutex		bf_lock;
++	unsigned long		bf_jiffy;
++	struct aufs_stfs	bf_stfs;
++	int			bf_readable;
++#endif
++};
++
++/* members for writable branch only */
++enum {AuBrWh_BASE, AuBrWh_PLINK, AuBrWh_ORPH, AuBrWh_Last};
++struct au_wbr {
++	struct au_rwsem		wbr_wh_rwsem;
++	struct dentry		*wbr_wh[AuBrWh_Last];
++	atomic_t		wbr_wh_running;
++#define wbr_whbase		wbr_wh[AuBrWh_BASE]	/* whiteout base */
++#define wbr_plink		wbr_wh[AuBrWh_PLINK]	/* pseudo-link dir */
++#define wbr_orph		wbr_wh[AuBrWh_ORPH]	/* dir for orphans */
++
++	/* mfs mode */
++	unsigned long long	wbr_bytes;
++};
++
++/* ext2 has 3 types of operations at least, ext3 has 4 */
++#define AuBrDynOp (AuDyLast * 4)
++
++#ifdef CONFIG_AUFS_HFSNOTIFY
++/* support for asynchronous destruction */
++struct au_br_hfsnotify {
++	struct fsnotify_group	*hfsn_group;
++};
++#endif
++
++/* sysfs entries */
++struct au_brsysfs {
++	char			name[16];
++	struct attribute	attr;
++};
++
++enum {
++	AuBrSysfs_BR,
++	AuBrSysfs_BRID,
++	AuBrSysfs_Last
++};
++
++/* protected by superblock rwsem */
++struct au_branch {
++	struct au_xino_file	br_xino;
++
++	aufs_bindex_t		br_id;
++
++	int			br_perm;
++	struct path		br_path;
++	spinlock_t		br_dykey_lock;
++	struct au_dykey		*br_dykey[AuBrDynOp];
++	atomic_t		br_count;
++
++	struct au_wbr		*br_wbr;
++	struct au_br_fhsm	*br_fhsm;
++
++	/* xino truncation */
++	atomic_t		br_xino_running;
++
++#ifdef CONFIG_AUFS_HFSNOTIFY
++	struct au_br_hfsnotify	*br_hfsn;
++#endif
++
++#ifdef CONFIG_SYSFS
++	/* entries under sysfs per mount-point */
++	struct au_brsysfs	br_sysfs[AuBrSysfs_Last];
++#endif
++};
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct vfsmount *au_br_mnt(struct au_branch *br)
++{
++	return br->br_path.mnt;
++}
++
++static inline struct dentry *au_br_dentry(struct au_branch *br)
++{
++	return br->br_path.dentry;
++}
++
++static inline struct super_block *au_br_sb(struct au_branch *br)
++{
++	return au_br_mnt(br)->mnt_sb;
++}
++
++static inline int au_br_rdonly(struct au_branch *br)
++{
++	return ((au_br_sb(br)->s_flags & MS_RDONLY)
++		|| !au_br_writable(br->br_perm))
++		? -EROFS : 0;
++}
++
++static inline int au_br_hnotifyable(int brperm __maybe_unused)
++{
++#ifdef CONFIG_AUFS_HNOTIFY
++	return !(brperm & AuBrPerm_RR);
++#else
++	return 0;
++#endif
++}
++
++static inline int au_br_test_oflag(int oflag, struct au_branch *br)
++{
++	int err, exec_flag;
++
++	err = 0;
++	exec_flag = oflag & __FMODE_EXEC;
++	if (unlikely(exec_flag && (au_br_mnt(br)->mnt_flags & MNT_NOEXEC)))
++		err = -EACCES;
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* branch.c */
++struct au_sbinfo;
++void au_br_free(struct au_sbinfo *sinfo);
++int au_br_index(struct super_block *sb, aufs_bindex_t br_id);
++struct au_opt_add;
++int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount);
++struct au_opt_del;
++int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount);
++long au_ibusy_ioctl(struct file *file, unsigned long arg);
++#ifdef CONFIG_COMPAT
++long au_ibusy_compat_ioctl(struct file *file, unsigned long arg);
++#endif
++struct au_opt_mod;
++int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
++	      int *do_refresh);
++struct aufs_stfs;
++int au_br_stfs(struct au_branch *br, struct aufs_stfs *stfs);
++
++/* xino.c */
++static const loff_t au_loff_max = LLONG_MAX;
++
++int au_xib_trunc(struct super_block *sb);
++ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
++		   loff_t *pos);
++ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
++		    loff_t *pos);
++struct file *au_xino_create2(struct file *base_file, struct file *copy_src);
++struct file *au_xino_create(struct super_block *sb, char *fname, int silent);
++ino_t au_xino_new_ino(struct super_block *sb);
++void au_xino_delete_inode(struct inode *inode, const int unlinked);
++int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		  ino_t ino);
++int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		 ino_t *ino);
++int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t hino,
++	       struct file *base_file, int do_test);
++int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex);
++
++struct au_opt_xino;
++int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount);
++void au_xino_clr(struct super_block *sb);
++struct file *au_xino_def(struct super_block *sb);
++int au_xino_path(struct seq_file *seq, struct file *file);
++
++/* ---------------------------------------------------------------------- */
++
++/* Superblock to branch */
++static inline
++aufs_bindex_t au_sbr_id(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_sbr(sb, bindex)->br_id;
++}
++
++static inline
++struct vfsmount *au_sbr_mnt(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_br_mnt(au_sbr(sb, bindex));
++}
++
++static inline
++struct super_block *au_sbr_sb(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_br_sb(au_sbr(sb, bindex));
++}
++
++static inline void au_sbr_put(struct super_block *sb, aufs_bindex_t bindex)
++{
++	atomic_dec(&au_sbr(sb, bindex)->br_count);
++}
++
++static inline int au_sbr_perm(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_sbr(sb, bindex)->br_perm;
++}
++
++static inline int au_sbr_whable(struct super_block *sb, aufs_bindex_t bindex)
++{
++	return au_br_whable(au_sbr_perm(sb, bindex));
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * wbr_wh_read_lock, wbr_wh_write_lock
++ * wbr_wh_read_unlock, wbr_wh_write_unlock, wbr_wh_downgrade_lock
++ */
++AuSimpleRwsemFuncs(wbr_wh, struct au_wbr *wbr, &wbr->wbr_wh_rwsem);
++
++#define WbrWhMustNoWaiters(wbr)	AuRwMustNoWaiters(&wbr->wbr_wh_rwsem)
++#define WbrWhMustAnyLock(wbr)	AuRwMustAnyLock(&wbr->wbr_wh_rwsem)
++#define WbrWhMustWriteLock(wbr)	AuRwMustWriteLock(&wbr->wbr_wh_rwsem)
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_FHSM
++static inline void au_br_fhsm_init(struct au_br_fhsm *brfhsm)
++{
++	mutex_init(&brfhsm->bf_lock);
++	brfhsm->bf_jiffy = 0;
++	brfhsm->bf_readable = 0;
++}
++
++static inline void au_br_fhsm_fin(struct au_br_fhsm *brfhsm)
++{
++	mutex_destroy(&brfhsm->bf_lock);
++}
++#else
++AuStubVoid(au_br_fhsm_init, struct au_br_fhsm *brfhsm)
++AuStubVoid(au_br_fhsm_fin, struct au_br_fhsm *brfhsm)
++#endif
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_BRANCH_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/cpup.c linux-4.0.4/fs/aufs/cpup.c
+--- linux-4.0.4.orig/fs/aufs/cpup.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/cpup.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,1295 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * copy-up functions, see wbr_policy.c for copy-down
++ */
++
++#include <linux/fs_stack.h>
++#include <linux/mm.h>
++#include "aufs.h"
++
++void au_cpup_attr_flags(struct inode *dst, unsigned int iflags)
++{
++	const unsigned int mask = S_DEAD | S_SWAPFILE | S_PRIVATE
++		| S_NOATIME | S_NOCMTIME | S_AUTOMOUNT;
++
++	BUILD_BUG_ON(sizeof(iflags) != sizeof(dst->i_flags));
++
++	dst->i_flags |= iflags & ~mask;
++	if (au_test_fs_notime(dst->i_sb))
++		dst->i_flags |= S_NOATIME | S_NOCMTIME;
++}
++
++void au_cpup_attr_timesizes(struct inode *inode)
++{
++	struct inode *h_inode;
++
++	h_inode = au_h_iptr(inode, au_ibstart(inode));
++	fsstack_copy_attr_times(inode, h_inode);
++	fsstack_copy_inode_size(inode, h_inode);
++}
++
++void au_cpup_attr_nlink(struct inode *inode, int force)
++{
++	struct inode *h_inode;
++	struct super_block *sb;
++	aufs_bindex_t bindex, bend;
++
++	sb = inode->i_sb;
++	bindex = au_ibstart(inode);
++	h_inode = au_h_iptr(inode, bindex);
++	if (!force
++	    && !S_ISDIR(h_inode->i_mode)
++	    && au_opt_test(au_mntflags(sb), PLINK)
++	    && au_plink_test(inode))
++		return;
++
++	/*
++	 * 0 can happen in revalidating.
++	 * h_inode->i_mutex may not be held here, but it is harmless since once
++	 * i_nlink reaches 0, it will never become positive except O_TMPFILE
++	 * case.
++	 * todo: O_TMPFILE+linkat(AT_SYMLINK_FOLLOW) bypassing aufs may cause
++	 *	 the incorrect link count.
++	 */
++	set_nlink(inode, h_inode->i_nlink);
++
++	/*
++	 * fewer nlink makes find(1) noisy, but larger nlink doesn't.
++	 * it may includes whplink directory.
++	 */
++	if (S_ISDIR(h_inode->i_mode)) {
++		bend = au_ibend(inode);
++		for (bindex++; bindex <= bend; bindex++) {
++			h_inode = au_h_iptr(inode, bindex);
++			if (h_inode)
++				au_add_nlink(inode, h_inode);
++		}
++	}
++}
++
++void au_cpup_attr_changeable(struct inode *inode)
++{
++	struct inode *h_inode;
++
++	h_inode = au_h_iptr(inode, au_ibstart(inode));
++	inode->i_mode = h_inode->i_mode;
++	inode->i_uid = h_inode->i_uid;
++	inode->i_gid = h_inode->i_gid;
++	au_cpup_attr_timesizes(inode);
++	au_cpup_attr_flags(inode, h_inode->i_flags);
++}
++
++void au_cpup_igen(struct inode *inode, struct inode *h_inode)
++{
++	struct au_iinfo *iinfo = au_ii(inode);
++
++	IiMustWriteLock(inode);
++
++	iinfo->ii_higen = h_inode->i_generation;
++	iinfo->ii_hsb1 = h_inode->i_sb;
++}
++
++void au_cpup_attr_all(struct inode *inode, int force)
++{
++	struct inode *h_inode;
++
++	h_inode = au_h_iptr(inode, au_ibstart(inode));
++	au_cpup_attr_changeable(inode);
++	if (inode->i_nlink > 0)
++		au_cpup_attr_nlink(inode, force);
++	inode->i_rdev = h_inode->i_rdev;
++	inode->i_blkbits = h_inode->i_blkbits;
++	au_cpup_igen(inode, h_inode);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* Note: dt_dentry and dt_h_dentry are not dget/dput-ed */
++
++/* keep the timestamps of the parent dir when cpup */
++void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
++		    struct path *h_path)
++{
++	struct inode *h_inode;
++
++	dt->dt_dentry = dentry;
++	dt->dt_h_path = *h_path;
++	h_inode = h_path->dentry->d_inode;
++	dt->dt_atime = h_inode->i_atime;
++	dt->dt_mtime = h_inode->i_mtime;
++	/* smp_mb(); */
++}
++
++void au_dtime_revert(struct au_dtime *dt)
++{
++	struct iattr attr;
++	int err;
++
++	attr.ia_atime = dt->dt_atime;
++	attr.ia_mtime = dt->dt_mtime;
++	attr.ia_valid = ATTR_FORCE | ATTR_MTIME | ATTR_MTIME_SET
++		| ATTR_ATIME | ATTR_ATIME_SET;
++
++	/* no delegation since this is a directory */
++	err = vfsub_notify_change(&dt->dt_h_path, &attr, /*delegated*/NULL);
++	if (unlikely(err))
++		pr_warn("restoring timestamps failed(%d). ignored\n", err);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* internal use only */
++struct au_cpup_reg_attr {
++	int		valid;
++	struct kstat	st;
++	unsigned int	iflags; /* inode->i_flags */
++};
++
++static noinline_for_stack
++int cpup_iattr(struct dentry *dst, aufs_bindex_t bindex, struct dentry *h_src,
++	       struct au_cpup_reg_attr *h_src_attr)
++{
++	int err, sbits, icex;
++	unsigned int mnt_flags;
++	unsigned char verbose;
++	struct iattr ia;
++	struct path h_path;
++	struct inode *h_isrc, *h_idst;
++	struct kstat *h_st;
++	struct au_branch *br;
++
++	h_path.dentry = au_h_dptr(dst, bindex);
++	h_idst = h_path.dentry->d_inode;
++	br = au_sbr(dst->d_sb, bindex);
++	h_path.mnt = au_br_mnt(br);
++	h_isrc = h_src->d_inode;
++	ia.ia_valid = ATTR_FORCE | ATTR_UID | ATTR_GID
++		| ATTR_ATIME | ATTR_MTIME
++		| ATTR_ATIME_SET | ATTR_MTIME_SET;
++	if (h_src_attr && h_src_attr->valid) {
++		h_st = &h_src_attr->st;
++		ia.ia_uid = h_st->uid;
++		ia.ia_gid = h_st->gid;
++		ia.ia_atime = h_st->atime;
++		ia.ia_mtime = h_st->mtime;
++		if (h_idst->i_mode != h_st->mode
++		    && !S_ISLNK(h_idst->i_mode)) {
++			ia.ia_valid |= ATTR_MODE;
++			ia.ia_mode = h_st->mode;
++		}
++		sbits = !!(h_st->mode & (S_ISUID | S_ISGID));
++		au_cpup_attr_flags(h_idst, h_src_attr->iflags);
++	} else {
++		ia.ia_uid = h_isrc->i_uid;
++		ia.ia_gid = h_isrc->i_gid;
++		ia.ia_atime = h_isrc->i_atime;
++		ia.ia_mtime = h_isrc->i_mtime;
++		if (h_idst->i_mode != h_isrc->i_mode
++		    && !S_ISLNK(h_idst->i_mode)) {
++			ia.ia_valid |= ATTR_MODE;
++			ia.ia_mode = h_isrc->i_mode;
++		}
++		sbits = !!(h_isrc->i_mode & (S_ISUID | S_ISGID));
++		au_cpup_attr_flags(h_idst, h_isrc->i_flags);
++	}
++	/* no delegation since it is just created */
++	err = vfsub_notify_change(&h_path, &ia, /*delegated*/NULL);
++
++	/* is this nfs only? */
++	if (!err && sbits && au_test_nfs(h_path.dentry->d_sb)) {
++		ia.ia_valid = ATTR_FORCE | ATTR_MODE;
++		ia.ia_mode = h_isrc->i_mode;
++		err = vfsub_notify_change(&h_path, &ia, /*delegated*/NULL);
++	}
++
++	icex = br->br_perm & AuBrAttr_ICEX;
++	if (!err) {
++		mnt_flags = au_mntflags(dst->d_sb);
++		verbose = !!au_opt_test(mnt_flags, VERBOSE);
++		err = au_cpup_xattr(h_path.dentry, h_src, icex, verbose);
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_do_copy_file(struct file *dst, struct file *src, loff_t len,
++			   char *buf, unsigned long blksize)
++{
++	int err;
++	size_t sz, rbytes, wbytes;
++	unsigned char all_zero;
++	char *p, *zp;
++	struct mutex *h_mtx;
++	/* reduce stack usage */
++	struct iattr *ia;
++
++	zp = page_address(ZERO_PAGE(0));
++	if (unlikely(!zp))
++		return -ENOMEM; /* possible? */
++
++	err = 0;
++	all_zero = 0;
++	while (len) {
++		AuDbg("len %lld\n", len);
++		sz = blksize;
++		if (len < blksize)
++			sz = len;
++
++		rbytes = 0;
++		/* todo: signal_pending? */
++		while (!rbytes || err == -EAGAIN || err == -EINTR) {
++			rbytes = vfsub_read_k(src, buf, sz, &src->f_pos);
++			err = rbytes;
++		}
++		if (unlikely(err < 0))
++			break;
++
++		all_zero = 0;
++		if (len >= rbytes && rbytes == blksize)
++			all_zero = !memcmp(buf, zp, rbytes);
++		if (!all_zero) {
++			wbytes = rbytes;
++			p = buf;
++			while (wbytes) {
++				size_t b;
++
++				b = vfsub_write_k(dst, p, wbytes, &dst->f_pos);
++				err = b;
++				/* todo: signal_pending? */
++				if (unlikely(err == -EAGAIN || err == -EINTR))
++					continue;
++				if (unlikely(err < 0))
++					break;
++				wbytes -= b;
++				p += b;
++			}
++			if (unlikely(err < 0))
++				break;
++		} else {
++			loff_t res;
++
++			AuLabel(hole);
++			res = vfsub_llseek(dst, rbytes, SEEK_CUR);
++			err = res;
++			if (unlikely(res < 0))
++				break;
++		}
++		len -= rbytes;
++		err = 0;
++	}
++
++	/* the last block may be a hole */
++	if (!err && all_zero) {
++		AuLabel(last hole);
++
++		err = 1;
++		if (au_test_nfs(dst->f_path.dentry->d_sb)) {
++			/* nfs requires this step to make last hole */
++			/* is this only nfs? */
++			do {
++				/* todo: signal_pending? */
++				err = vfsub_write_k(dst, "\0", 1, &dst->f_pos);
++			} while (err == -EAGAIN || err == -EINTR);
++			if (err == 1)
++				dst->f_pos--;
++		}
++
++		if (err == 1) {
++			ia = (void *)buf;
++			ia->ia_size = dst->f_pos;
++			ia->ia_valid = ATTR_SIZE | ATTR_FILE;
++			ia->ia_file = dst;
++			h_mtx = &file_inode(dst)->i_mutex;
++			mutex_lock_nested(h_mtx, AuLsc_I_CHILD2);
++			/* no delegation since it is just created */
++			err = vfsub_notify_change(&dst->f_path, ia,
++						  /*delegated*/NULL);
++			mutex_unlock(h_mtx);
++		}
++	}
++
++	return err;
++}
++
++int au_copy_file(struct file *dst, struct file *src, loff_t len)
++{
++	int err;
++	unsigned long blksize;
++	unsigned char do_kfree;
++	char *buf;
++
++	err = -ENOMEM;
++	blksize = dst->f_path.dentry->d_sb->s_blocksize;
++	if (!blksize || PAGE_SIZE < blksize)
++		blksize = PAGE_SIZE;
++	AuDbg("blksize %lu\n", blksize);
++	do_kfree = (blksize != PAGE_SIZE && blksize >= sizeof(struct iattr *));
++	if (do_kfree)
++		buf = kmalloc(blksize, GFP_NOFS);
++	else
++		buf = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!buf))
++		goto out;
++
++	if (len > (1 << 22))
++		AuDbg("copying a large file %lld\n", (long long)len);
++
++	src->f_pos = 0;
++	dst->f_pos = 0;
++	err = au_do_copy_file(dst, src, len, buf, blksize);
++	if (do_kfree)
++		kfree(buf);
++	else
++		free_page((unsigned long)buf);
++
++out:
++	return err;
++}
++
++/*
++ * to support a sparse file which is opened with O_APPEND,
++ * we need to close the file.
++ */
++static int au_cp_regular(struct au_cp_generic *cpg)
++{
++	int err, i;
++	enum { SRC, DST };
++	struct {
++		aufs_bindex_t bindex;
++		unsigned int flags;
++		struct dentry *dentry;
++		int force_wr;
++		struct file *file;
++		void *label;
++	} *f, file[] = {
++		{
++			.bindex = cpg->bsrc,
++			.flags = O_RDONLY | O_NOATIME | O_LARGEFILE,
++			.label = &&out
++		},
++		{
++			.bindex = cpg->bdst,
++			.flags = O_WRONLY | O_NOATIME | O_LARGEFILE,
++			.force_wr = !!au_ftest_cpup(cpg->flags, RWDST),
++			.label = &&out_src
++		}
++	};
++	struct super_block *sb;
++
++	/* bsrc branch can be ro/rw. */
++	sb = cpg->dentry->d_sb;
++	f = file;
++	for (i = 0; i < 2; i++, f++) {
++		f->dentry = au_h_dptr(cpg->dentry, f->bindex);
++		f->file = au_h_open(cpg->dentry, f->bindex, f->flags,
++				    /*file*/NULL, f->force_wr);
++		err = PTR_ERR(f->file);
++		if (IS_ERR(f->file))
++			goto *f->label;
++	}
++
++	/* try stopping to update while we copyup */
++	IMustLock(file[SRC].dentry->d_inode);
++	err = au_copy_file(file[DST].file, file[SRC].file, cpg->len);
++
++	fput(file[DST].file);
++	au_sbr_put(sb, file[DST].bindex);
++
++out_src:
++	fput(file[SRC].file);
++	au_sbr_put(sb, file[SRC].bindex);
++out:
++	return err;
++}
++
++static int au_do_cpup_regular(struct au_cp_generic *cpg,
++			      struct au_cpup_reg_attr *h_src_attr)
++{
++	int err, rerr;
++	loff_t l;
++	struct path h_path;
++	struct inode *h_src_inode, *h_dst_inode;
++
++	err = 0;
++	h_src_inode = au_h_iptr(cpg->dentry->d_inode, cpg->bsrc);
++	l = i_size_read(h_src_inode);
++	if (cpg->len == -1 || l < cpg->len)
++		cpg->len = l;
++	if (cpg->len) {
++		/* try stopping to update while we are referencing */
++		mutex_lock_nested(&h_src_inode->i_mutex, AuLsc_I_CHILD);
++		au_pin_hdir_unlock(cpg->pin);
++
++		h_path.dentry = au_h_dptr(cpg->dentry, cpg->bsrc);
++		h_path.mnt = au_sbr_mnt(cpg->dentry->d_sb, cpg->bsrc);
++		h_src_attr->iflags = h_src_inode->i_flags;
++		err = vfs_getattr(&h_path, &h_src_attr->st);
++		if (unlikely(err)) {
++			mutex_unlock(&h_src_inode->i_mutex);
++			goto out;
++		}
++		h_src_attr->valid = 1;
++		err = au_cp_regular(cpg);
++		mutex_unlock(&h_src_inode->i_mutex);
++		rerr = au_pin_hdir_relock(cpg->pin);
++		if (!err && rerr)
++			err = rerr;
++	}
++	if (!err && (h_src_inode->i_state & I_LINKABLE)) {
++		h_path.dentry = au_h_dptr(cpg->dentry, cpg->bdst);
++		h_dst_inode = h_path.dentry->d_inode;
++		spin_lock(&h_dst_inode->i_lock);
++		h_dst_inode->i_state |= I_LINKABLE;
++		spin_unlock(&h_dst_inode->i_lock);
++	}
++
++out:
++	return err;
++}
++
++static int au_do_cpup_symlink(struct path *h_path, struct dentry *h_src,
++			      struct inode *h_dir)
++{
++	int err, symlen;
++	mm_segment_t old_fs;
++	union {
++		char *k;
++		char __user *u;
++	} sym;
++
++	err = -ENOSYS;
++	if (unlikely(!h_src->d_inode->i_op->readlink))
++		goto out;
++
++	err = -ENOMEM;
++	sym.k = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!sym.k))
++		goto out;
++
++	/* unnecessary to support mmap_sem since symlink is not mmap-able */
++	old_fs = get_fs();
++	set_fs(KERNEL_DS);
++	symlen = h_src->d_inode->i_op->readlink(h_src, sym.u, PATH_MAX);
++	err = symlen;
++	set_fs(old_fs);
++
++	if (symlen > 0) {
++		sym.k[symlen] = 0;
++		err = vfsub_symlink(h_dir, h_path, sym.k);
++	}
++	free_page((unsigned long)sym.k);
++
++out:
++	return err;
++}
++
++static noinline_for_stack
++int cpup_entry(struct au_cp_generic *cpg, struct dentry *dst_parent,
++	       struct au_cpup_reg_attr *h_src_attr)
++{
++	int err;
++	umode_t mode;
++	unsigned int mnt_flags;
++	unsigned char isdir, isreg, force;
++	const unsigned char do_dt = !!au_ftest_cpup(cpg->flags, DTIME);
++	struct au_dtime dt;
++	struct path h_path;
++	struct dentry *h_src, *h_dst, *h_parent;
++	struct inode *h_inode, *h_dir;
++	struct super_block *sb;
++
++	/* bsrc branch can be ro/rw. */
++	h_src = au_h_dptr(cpg->dentry, cpg->bsrc);
++	h_inode = h_src->d_inode;
++	AuDebugOn(h_inode != au_h_iptr(cpg->dentry->d_inode, cpg->bsrc));
++
++	/* try stopping to be referenced while we are creating */
++	h_dst = au_h_dptr(cpg->dentry, cpg->bdst);
++	if (au_ftest_cpup(cpg->flags, RENAME))
++		AuDebugOn(strncmp(h_dst->d_name.name, AUFS_WH_PFX,
++				  AUFS_WH_PFX_LEN));
++	h_parent = h_dst->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++	AuDebugOn(h_parent != h_dst->d_parent);
++
++	sb = cpg->dentry->d_sb;
++	h_path.mnt = au_sbr_mnt(sb, cpg->bdst);
++	if (do_dt) {
++		h_path.dentry = h_parent;
++		au_dtime_store(&dt, dst_parent, &h_path);
++	}
++	h_path.dentry = h_dst;
++
++	isreg = 0;
++	isdir = 0;
++	mode = h_inode->i_mode;
++	switch (mode & S_IFMT) {
++	case S_IFREG:
++		isreg = 1;
++		err = vfsub_create(h_dir, &h_path, mode | S_IWUSR,
++				   /*want_excl*/true);
++		if (!err)
++			err = au_do_cpup_regular(cpg, h_src_attr);
++		break;
++	case S_IFDIR:
++		isdir = 1;
++		err = vfsub_mkdir(h_dir, &h_path, mode);
++		if (!err) {
++			/*
++			 * strange behaviour from the users view,
++			 * particularry setattr case
++			 */
++			if (au_ibstart(dst_parent->d_inode) == cpg->bdst)
++				au_cpup_attr_nlink(dst_parent->d_inode,
++						   /*force*/1);
++			au_cpup_attr_nlink(cpg->dentry->d_inode, /*force*/1);
++		}
++		break;
++	case S_IFLNK:
++		err = au_do_cpup_symlink(&h_path, h_src, h_dir);
++		break;
++	case S_IFCHR:
++	case S_IFBLK:
++		AuDebugOn(!capable(CAP_MKNOD));
++		/*FALLTHROUGH*/
++	case S_IFIFO:
++	case S_IFSOCK:
++		err = vfsub_mknod(h_dir, &h_path, mode, h_inode->i_rdev);
++		break;
++	default:
++		AuIOErr("Unknown inode type 0%o\n", mode);
++		err = -EIO;
++	}
++
++	mnt_flags = au_mntflags(sb);
++	if (!au_opt_test(mnt_flags, UDBA_NONE)
++	    && !isdir
++	    && au_opt_test(mnt_flags, XINO)
++	    && (h_inode->i_nlink == 1
++		|| (h_inode->i_state & I_LINKABLE))
++	    /* todo: unnecessary? */
++	    /* && cpg->dentry->d_inode->i_nlink == 1 */
++	    && cpg->bdst < cpg->bsrc
++	    && !au_ftest_cpup(cpg->flags, KEEPLINO))
++		au_xino_write(sb, cpg->bsrc, h_inode->i_ino, /*ino*/0);
++		/* ignore this error */
++
++	if (!err) {
++		force = 0;
++		if (isreg) {
++			force = !!cpg->len;
++			if (cpg->len == -1)
++				force = !!i_size_read(h_inode);
++		}
++		au_fhsm_wrote(sb, cpg->bdst, force);
++	}
++
++	if (do_dt)
++		au_dtime_revert(&dt);
++	return err;
++}
++
++static int au_do_ren_after_cpup(struct au_cp_generic *cpg, struct path *h_path)
++{
++	int err;
++	struct dentry *dentry, *h_dentry, *h_parent, *parent;
++	struct inode *h_dir;
++	aufs_bindex_t bdst;
++
++	dentry = cpg->dentry;
++	bdst = cpg->bdst;
++	h_dentry = au_h_dptr(dentry, bdst);
++	if (!au_ftest_cpup(cpg->flags, OVERWRITE)) {
++		dget(h_dentry);
++		au_set_h_dptr(dentry, bdst, NULL);
++		err = au_lkup_neg(dentry, bdst, /*wh*/0);
++		if (!err)
++			h_path->dentry = dget(au_h_dptr(dentry, bdst));
++		au_set_h_dptr(dentry, bdst, h_dentry);
++	} else {
++		err = 0;
++		parent = dget_parent(dentry);
++		h_parent = au_h_dptr(parent, bdst);
++		dput(parent);
++		h_path->dentry = vfsub_lkup_one(&dentry->d_name, h_parent);
++		if (IS_ERR(h_path->dentry))
++			err = PTR_ERR(h_path->dentry);
++	}
++	if (unlikely(err))
++		goto out;
++
++	h_parent = h_dentry->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++	AuDbg("%pd %pd\n", h_dentry, h_path->dentry);
++	/* no delegation since it is just created */
++	err = vfsub_rename(h_dir, h_dentry, h_dir, h_path, /*delegated*/NULL);
++	dput(h_path->dentry);
++
++out:
++	return err;
++}
++
++/*
++ * copyup the @dentry from @bsrc to @bdst.
++ * the caller must set the both of lower dentries.
++ * @len is for truncating when it is -1 copyup the entire file.
++ * in link/rename cases, @dst_parent may be different from the real one.
++ * basic->bsrc can be larger than basic->bdst.
++ */
++static int au_cpup_single(struct au_cp_generic *cpg, struct dentry *dst_parent)
++{
++	int err, rerr;
++	aufs_bindex_t old_ibstart;
++	unsigned char isdir, plink;
++	struct dentry *h_src, *h_dst, *h_parent;
++	struct inode *dst_inode, *h_dir, *inode, *delegated;
++	struct super_block *sb;
++	struct au_branch *br;
++	/* to reuduce stack size */
++	struct {
++		struct au_dtime dt;
++		struct path h_path;
++		struct au_cpup_reg_attr h_src_attr;
++	} *a;
++
++	err = -ENOMEM;
++	a = kmalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++	a->h_src_attr.valid = 0;
++
++	sb = cpg->dentry->d_sb;
++	br = au_sbr(sb, cpg->bdst);
++	a->h_path.mnt = au_br_mnt(br);
++	h_dst = au_h_dptr(cpg->dentry, cpg->bdst);
++	h_parent = h_dst->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++
++	h_src = au_h_dptr(cpg->dentry, cpg->bsrc);
++	inode = cpg->dentry->d_inode;
++
++	if (!dst_parent)
++		dst_parent = dget_parent(cpg->dentry);
++	else
++		dget(dst_parent);
++
++	plink = !!au_opt_test(au_mntflags(sb), PLINK);
++	dst_inode = au_h_iptr(inode, cpg->bdst);
++	if (dst_inode) {
++		if (unlikely(!plink)) {
++			err = -EIO;
++			AuIOErr("hi%lu(i%lu) exists on b%d "
++				"but plink is disabled\n",
++				dst_inode->i_ino, inode->i_ino, cpg->bdst);
++			goto out_parent;
++		}
++
++		if (dst_inode->i_nlink) {
++			const int do_dt = au_ftest_cpup(cpg->flags, DTIME);
++
++			h_src = au_plink_lkup(inode, cpg->bdst);
++			err = PTR_ERR(h_src);
++			if (IS_ERR(h_src))
++				goto out_parent;
++			if (unlikely(!h_src->d_inode)) {
++				err = -EIO;
++				AuIOErr("i%lu exists on a upper branch "
++					"but not pseudo-linked\n",
++					inode->i_ino);
++				dput(h_src);
++				goto out_parent;
++			}
++
++			if (do_dt) {
++				a->h_path.dentry = h_parent;
++				au_dtime_store(&a->dt, dst_parent, &a->h_path);
++			}
++
++			a->h_path.dentry = h_dst;
++			delegated = NULL;
++			err = vfsub_link(h_src, h_dir, &a->h_path, &delegated);
++			if (!err && au_ftest_cpup(cpg->flags, RENAME))
++				err = au_do_ren_after_cpup(cpg, &a->h_path);
++			if (do_dt)
++				au_dtime_revert(&a->dt);
++			if (unlikely(err == -EWOULDBLOCK)) {
++				pr_warn("cannot retry for NFSv4 delegation"
++					" for an internal link\n");
++				iput(delegated);
++			}
++			dput(h_src);
++			goto out_parent;
++		} else
++			/* todo: cpup_wh_file? */
++			/* udba work */
++			au_update_ibrange(inode, /*do_put_zero*/1);
++	}
++
++	isdir = S_ISDIR(inode->i_mode);
++	old_ibstart = au_ibstart(inode);
++	err = cpup_entry(cpg, dst_parent, &a->h_src_attr);
++	if (unlikely(err))
++		goto out_rev;
++	dst_inode = h_dst->d_inode;
++	mutex_lock_nested(&dst_inode->i_mutex, AuLsc_I_CHILD2);
++	/* todo: necessary? */
++	/* au_pin_hdir_unlock(cpg->pin); */
++
++	err = cpup_iattr(cpg->dentry, cpg->bdst, h_src, &a->h_src_attr);
++	if (unlikely(err)) {
++		/* todo: necessary? */
++		/* au_pin_hdir_relock(cpg->pin); */ /* ignore an error */
++		mutex_unlock(&dst_inode->i_mutex);
++		goto out_rev;
++	}
++
++	if (cpg->bdst < old_ibstart) {
++		if (S_ISREG(inode->i_mode)) {
++			err = au_dy_iaop(inode, cpg->bdst, dst_inode);
++			if (unlikely(err)) {
++				/* ignore an error */
++				/* au_pin_hdir_relock(cpg->pin); */
++				mutex_unlock(&dst_inode->i_mutex);
++				goto out_rev;
++			}
++		}
++		au_set_ibstart(inode, cpg->bdst);
++	} else
++		au_set_ibend(inode, cpg->bdst);
++	au_set_h_iptr(inode, cpg->bdst, au_igrab(dst_inode),
++		      au_hi_flags(inode, isdir));
++
++	/* todo: necessary? */
++	/* err = au_pin_hdir_relock(cpg->pin); */
++	mutex_unlock(&dst_inode->i_mutex);
++	if (unlikely(err))
++		goto out_rev;
++
++	if (!isdir
++	    && (h_src->d_inode->i_nlink > 1
++		|| h_src->d_inode->i_state & I_LINKABLE)
++	    && plink)
++		au_plink_append(inode, cpg->bdst, h_dst);
++
++	if (au_ftest_cpup(cpg->flags, RENAME)) {
++		a->h_path.dentry = h_dst;
++		err = au_do_ren_after_cpup(cpg, &a->h_path);
++	}
++	if (!err)
++		goto out_parent; /* success */
++
++	/* revert */
++out_rev:
++	a->h_path.dentry = h_parent;
++	au_dtime_store(&a->dt, dst_parent, &a->h_path);
++	a->h_path.dentry = h_dst;
++	rerr = 0;
++	if (h_dst->d_inode) {
++		if (!isdir) {
++			/* no delegation since it is just created */
++			rerr = vfsub_unlink(h_dir, &a->h_path,
++					    /*delegated*/NULL, /*force*/0);
++		} else
++			rerr = vfsub_rmdir(h_dir, &a->h_path);
++	}
++	au_dtime_revert(&a->dt);
++	if (rerr) {
++		AuIOErr("failed removing broken entry(%d, %d)\n", err, rerr);
++		err = -EIO;
++	}
++out_parent:
++	dput(dst_parent);
++	kfree(a);
++out:
++	return err;
++}
++
++#if 0 /* reserved */
++struct au_cpup_single_args {
++	int *errp;
++	struct au_cp_generic *cpg;
++	struct dentry *dst_parent;
++};
++
++static void au_call_cpup_single(void *args)
++{
++	struct au_cpup_single_args *a = args;
++
++	au_pin_hdir_acquire_nest(a->cpg->pin);
++	*a->errp = au_cpup_single(a->cpg, a->dst_parent);
++	au_pin_hdir_release(a->cpg->pin);
++}
++#endif
++
++/*
++ * prevent SIGXFSZ in copy-up.
++ * testing CAP_MKNOD is for generic fs,
++ * but CAP_FSETID is for xfs only, currently.
++ */
++static int au_cpup_sio_test(struct au_pin *pin, umode_t mode)
++{
++	int do_sio;
++	struct super_block *sb;
++	struct inode *h_dir;
++
++	do_sio = 0;
++	sb = au_pinned_parent(pin)->d_sb;
++	if (!au_wkq_test()
++	    && (!au_sbi(sb)->si_plink_maint_pid
++		|| au_plink_maint(sb, AuLock_NOPLM))) {
++		switch (mode & S_IFMT) {
++		case S_IFREG:
++			/* no condition about RLIMIT_FSIZE and the file size */
++			do_sio = 1;
++			break;
++		case S_IFCHR:
++		case S_IFBLK:
++			do_sio = !capable(CAP_MKNOD);
++			break;
++		}
++		if (!do_sio)
++			do_sio = ((mode & (S_ISUID | S_ISGID))
++				  && !capable(CAP_FSETID));
++		/* this workaround may be removed in the future */
++		if (!do_sio) {
++			h_dir = au_pinned_h_dir(pin);
++			do_sio = h_dir->i_mode & S_ISVTX;
++		}
++	}
++
++	return do_sio;
++}
++
++#if 0 /* reserved */
++int au_sio_cpup_single(struct au_cp_generic *cpg, struct dentry *dst_parent)
++{
++	int err, wkq_err;
++	struct dentry *h_dentry;
++
++	h_dentry = au_h_dptr(cpg->dentry, cpg->bsrc);
++	if (!au_cpup_sio_test(pin, h_dentry->d_inode->i_mode))
++		err = au_cpup_single(cpg, dst_parent);
++	else {
++		struct au_cpup_single_args args = {
++			.errp		= &err,
++			.cpg		= cpg,
++			.dst_parent	= dst_parent
++		};
++		wkq_err = au_wkq_wait(au_call_cpup_single, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
++#endif
++
++/*
++ * copyup the @dentry from the first active lower branch to @bdst,
++ * using au_cpup_single().
++ */
++static int au_cpup_simple(struct au_cp_generic *cpg)
++{
++	int err;
++	unsigned int flags_orig;
++	struct dentry *dentry;
++
++	AuDebugOn(cpg->bsrc < 0);
++
++	dentry = cpg->dentry;
++	DiMustWriteLock(dentry);
++
++	err = au_lkup_neg(dentry, cpg->bdst, /*wh*/1);
++	if (!err) {
++		flags_orig = cpg->flags;
++		au_fset_cpup(cpg->flags, RENAME);
++		err = au_cpup_single(cpg, NULL);
++		cpg->flags = flags_orig;
++		if (!err)
++			return 0; /* success */
++
++		/* revert */
++		au_set_h_dptr(dentry, cpg->bdst, NULL);
++		au_set_dbstart(dentry, cpg->bsrc);
++	}
++
++	return err;
++}
++
++struct au_cpup_simple_args {
++	int *errp;
++	struct au_cp_generic *cpg;
++};
++
++static void au_call_cpup_simple(void *args)
++{
++	struct au_cpup_simple_args *a = args;
++
++	au_pin_hdir_acquire_nest(a->cpg->pin);
++	*a->errp = au_cpup_simple(a->cpg);
++	au_pin_hdir_release(a->cpg->pin);
++}
++
++static int au_do_sio_cpup_simple(struct au_cp_generic *cpg)
++{
++	int err, wkq_err;
++	struct dentry *dentry, *parent;
++	struct file *h_file;
++	struct inode *h_dir;
++
++	dentry = cpg->dentry;
++	h_file = NULL;
++	if (au_ftest_cpup(cpg->flags, HOPEN)) {
++		AuDebugOn(cpg->bsrc < 0);
++		h_file = au_h_open_pre(dentry, cpg->bsrc, /*force_wr*/0);
++		err = PTR_ERR(h_file);
++		if (IS_ERR(h_file))
++			goto out;
++	}
++
++	parent = dget_parent(dentry);
++	h_dir = au_h_iptr(parent->d_inode, cpg->bdst);
++	if (!au_test_h_perm_sio(h_dir, MAY_EXEC | MAY_WRITE)
++	    && !au_cpup_sio_test(cpg->pin, dentry->d_inode->i_mode))
++		err = au_cpup_simple(cpg);
++	else {
++		struct au_cpup_simple_args args = {
++			.errp		= &err,
++			.cpg		= cpg
++		};
++		wkq_err = au_wkq_wait(au_call_cpup_simple, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	dput(parent);
++	if (h_file)
++		au_h_open_post(dentry, cpg->bsrc, h_file);
++
++out:
++	return err;
++}
++
++int au_sio_cpup_simple(struct au_cp_generic *cpg)
++{
++	aufs_bindex_t bsrc, bend;
++	struct dentry *dentry, *h_dentry;
++
++	if (cpg->bsrc < 0) {
++		dentry = cpg->dentry;
++		bend = au_dbend(dentry);
++		for (bsrc = cpg->bdst + 1; bsrc <= bend; bsrc++) {
++			h_dentry = au_h_dptr(dentry, bsrc);
++			if (h_dentry) {
++				AuDebugOn(!h_dentry->d_inode);
++				break;
++			}
++		}
++		AuDebugOn(bsrc > bend);
++		cpg->bsrc = bsrc;
++	}
++	AuDebugOn(cpg->bsrc <= cpg->bdst);
++	return au_do_sio_cpup_simple(cpg);
++}
++
++int au_sio_cpdown_simple(struct au_cp_generic *cpg)
++{
++	AuDebugOn(cpg->bdst <= cpg->bsrc);
++	return au_do_sio_cpup_simple(cpg);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * copyup the deleted file for writing.
++ */
++static int au_do_cpup_wh(struct au_cp_generic *cpg, struct dentry *wh_dentry,
++			 struct file *file)
++{
++	int err;
++	unsigned int flags_orig;
++	aufs_bindex_t bsrc_orig;
++	struct dentry *h_d_dst, *h_d_start;
++	struct au_dinfo *dinfo;
++	struct au_hdentry *hdp;
++
++	dinfo = au_di(cpg->dentry);
++	AuRwMustWriteLock(&dinfo->di_rwsem);
++
++	bsrc_orig = cpg->bsrc;
++	cpg->bsrc = dinfo->di_bstart;
++	hdp = dinfo->di_hdentry;
++	h_d_dst = hdp[0 + cpg->bdst].hd_dentry;
++	dinfo->di_bstart = cpg->bdst;
++	hdp[0 + cpg->bdst].hd_dentry = wh_dentry;
++	h_d_start = NULL;
++	if (file) {
++		h_d_start = hdp[0 + cpg->bsrc].hd_dentry;
++		hdp[0 + cpg->bsrc].hd_dentry = au_hf_top(file)->f_path.dentry;
++	}
++	flags_orig = cpg->flags;
++	cpg->flags = !AuCpup_DTIME;
++	err = au_cpup_single(cpg, /*h_parent*/NULL);
++	cpg->flags = flags_orig;
++	if (file) {
++		if (!err)
++			err = au_reopen_nondir(file);
++		hdp[0 + cpg->bsrc].hd_dentry = h_d_start;
++	}
++	hdp[0 + cpg->bdst].hd_dentry = h_d_dst;
++	dinfo->di_bstart = cpg->bsrc;
++	cpg->bsrc = bsrc_orig;
++
++	return err;
++}
++
++static int au_cpup_wh(struct au_cp_generic *cpg, struct file *file)
++{
++	int err;
++	aufs_bindex_t bdst;
++	struct au_dtime dt;
++	struct dentry *dentry, *parent, *h_parent, *wh_dentry;
++	struct au_branch *br;
++	struct path h_path;
++
++	dentry = cpg->dentry;
++	bdst = cpg->bdst;
++	br = au_sbr(dentry->d_sb, bdst);
++	parent = dget_parent(dentry);
++	h_parent = au_h_dptr(parent, bdst);
++	wh_dentry = au_whtmp_lkup(h_parent, br, &dentry->d_name);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out;
++
++	h_path.dentry = h_parent;
++	h_path.mnt = au_br_mnt(br);
++	au_dtime_store(&dt, parent, &h_path);
++	err = au_do_cpup_wh(cpg, wh_dentry, file);
++	if (unlikely(err))
++		goto out_wh;
++
++	dget(wh_dentry);
++	h_path.dentry = wh_dentry;
++	if (!d_is_dir(wh_dentry)) {
++		/* no delegation since it is just created */
++		err = vfsub_unlink(h_parent->d_inode, &h_path,
++				   /*delegated*/NULL, /*force*/0);
++	} else
++		err = vfsub_rmdir(h_parent->d_inode, &h_path);
++	if (unlikely(err)) {
++		AuIOErr("failed remove copied-up tmp file %pd(%d)\n",
++			wh_dentry, err);
++		err = -EIO;
++	}
++	au_dtime_revert(&dt);
++	au_set_hi_wh(dentry->d_inode, bdst, wh_dentry);
++
++out_wh:
++	dput(wh_dentry);
++out:
++	dput(parent);
++	return err;
++}
++
++struct au_cpup_wh_args {
++	int *errp;
++	struct au_cp_generic *cpg;
++	struct file *file;
++};
++
++static void au_call_cpup_wh(void *args)
++{
++	struct au_cpup_wh_args *a = args;
++
++	au_pin_hdir_acquire_nest(a->cpg->pin);
++	*a->errp = au_cpup_wh(a->cpg, a->file);
++	au_pin_hdir_release(a->cpg->pin);
++}
++
++int au_sio_cpup_wh(struct au_cp_generic *cpg, struct file *file)
++{
++	int err, wkq_err;
++	aufs_bindex_t bdst;
++	struct dentry *dentry, *parent, *h_orph, *h_parent;
++	struct inode *dir, *h_dir, *h_tmpdir;
++	struct au_wbr *wbr;
++	struct au_pin wh_pin, *pin_orig;
++
++	dentry = cpg->dentry;
++	bdst = cpg->bdst;
++	parent = dget_parent(dentry);
++	dir = parent->d_inode;
++	h_orph = NULL;
++	h_parent = NULL;
++	h_dir = au_igrab(au_h_iptr(dir, bdst));
++	h_tmpdir = h_dir;
++	pin_orig = NULL;
++	if (!h_dir->i_nlink) {
++		wbr = au_sbr(dentry->d_sb, bdst)->br_wbr;
++		h_orph = wbr->wbr_orph;
++
++		h_parent = dget(au_h_dptr(parent, bdst));
++		au_set_h_dptr(parent, bdst, dget(h_orph));
++		h_tmpdir = h_orph->d_inode;
++		au_set_h_iptr(dir, bdst, au_igrab(h_tmpdir), /*flags*/0);
++
++		mutex_lock_nested(&h_tmpdir->i_mutex, AuLsc_I_PARENT3);
++		/* todo: au_h_open_pre()? */
++
++		pin_orig = cpg->pin;
++		au_pin_init(&wh_pin, dentry, bdst, AuLsc_DI_PARENT,
++			    AuLsc_I_PARENT3, cpg->pin->udba, AuPin_DI_LOCKED);
++		cpg->pin = &wh_pin;
++	}
++
++	if (!au_test_h_perm_sio(h_tmpdir, MAY_EXEC | MAY_WRITE)
++	    && !au_cpup_sio_test(cpg->pin, dentry->d_inode->i_mode))
++		err = au_cpup_wh(cpg, file);
++	else {
++		struct au_cpup_wh_args args = {
++			.errp	= &err,
++			.cpg	= cpg,
++			.file	= file
++		};
++		wkq_err = au_wkq_wait(au_call_cpup_wh, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	if (h_orph) {
++		mutex_unlock(&h_tmpdir->i_mutex);
++		/* todo: au_h_open_post()? */
++		au_set_h_iptr(dir, bdst, au_igrab(h_dir), /*flags*/0);
++		au_set_h_dptr(parent, bdst, h_parent);
++		AuDebugOn(!pin_orig);
++		cpg->pin = pin_orig;
++	}
++	iput(h_dir);
++	dput(parent);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * generic routine for both of copy-up and copy-down.
++ */
++/* cf. revalidate function in file.c */
++int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
++	       int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
++			 struct au_pin *pin,
++			 struct dentry *h_parent, void *arg),
++	       void *arg)
++{
++	int err;
++	struct au_pin pin;
++	struct dentry *d, *parent, *h_parent, *real_parent;
++
++	err = 0;
++	parent = dget_parent(dentry);
++	if (IS_ROOT(parent))
++		goto out;
++
++	au_pin_init(&pin, dentry, bdst, AuLsc_DI_PARENT2, AuLsc_I_PARENT2,
++		    au_opt_udba(dentry->d_sb), AuPin_MNT_WRITE);
++
++	/* do not use au_dpage */
++	real_parent = parent;
++	while (1) {
++		dput(parent);
++		parent = dget_parent(dentry);
++		h_parent = au_h_dptr(parent, bdst);
++		if (h_parent)
++			goto out; /* success */
++
++		/* find top dir which is necessary to cpup */
++		do {
++			d = parent;
++			dput(parent);
++			parent = dget_parent(d);
++			di_read_lock_parent3(parent, !AuLock_IR);
++			h_parent = au_h_dptr(parent, bdst);
++			di_read_unlock(parent, !AuLock_IR);
++		} while (!h_parent);
++
++		if (d != real_parent)
++			di_write_lock_child3(d);
++
++		/* somebody else might create while we were sleeping */
++		if (!au_h_dptr(d, bdst) || !au_h_dptr(d, bdst)->d_inode) {
++			if (au_h_dptr(d, bdst))
++				au_update_dbstart(d);
++
++			au_pin_set_dentry(&pin, d);
++			err = au_do_pin(&pin);
++			if (!err) {
++				err = cp(d, bdst, &pin, h_parent, arg);
++				au_unpin(&pin);
++			}
++		}
++
++		if (d != real_parent)
++			di_write_unlock(d);
++		if (unlikely(err))
++			break;
++	}
++
++out:
++	dput(parent);
++	return err;
++}
++
++static int au_cpup_dir(struct dentry *dentry, aufs_bindex_t bdst,
++		       struct au_pin *pin,
++		       struct dentry *h_parent __maybe_unused,
++		       void *arg __maybe_unused)
++{
++	struct au_cp_generic cpg = {
++		.dentry	= dentry,
++		.bdst	= bdst,
++		.bsrc	= -1,
++		.len	= 0,
++		.pin	= pin,
++		.flags	= AuCpup_DTIME
++	};
++	return au_sio_cpup_simple(&cpg);
++}
++
++int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
++{
++	return au_cp_dirs(dentry, bdst, au_cpup_dir, NULL);
++}
++
++int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
++{
++	int err;
++	struct dentry *parent;
++	struct inode *dir;
++
++	parent = dget_parent(dentry);
++	dir = parent->d_inode;
++	err = 0;
++	if (au_h_iptr(dir, bdst))
++		goto out;
++
++	di_read_unlock(parent, AuLock_IR);
++	di_write_lock_parent(parent);
++	/* someone else might change our inode while we were sleeping */
++	if (!au_h_iptr(dir, bdst))
++		err = au_cpup_dirs(dentry, bdst);
++	di_downgrade_lock(parent, AuLock_IR);
++
++out:
++	dput(parent);
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/cpup.h linux-4.0.4/fs/aufs/cpup.h
+--- linux-4.0.4.orig/fs/aufs/cpup.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/cpup.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,81 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * copy-up/down functions
++ */
++
++#ifndef __AUFS_CPUP_H__
++#define __AUFS_CPUP_H__
++
++#ifdef __KERNEL__
++
++#include <linux/path.h>
++
++struct inode;
++struct file;
++struct au_pin;
++
++void au_cpup_attr_flags(struct inode *dst, unsigned int iflags);
++void au_cpup_attr_timesizes(struct inode *inode);
++void au_cpup_attr_nlink(struct inode *inode, int force);
++void au_cpup_attr_changeable(struct inode *inode);
++void au_cpup_igen(struct inode *inode, struct inode *h_inode);
++void au_cpup_attr_all(struct inode *inode, int force);
++
++/* ---------------------------------------------------------------------- */
++
++struct au_cp_generic {
++	struct dentry	*dentry;
++	aufs_bindex_t	bdst, bsrc;
++	loff_t		len;
++	struct au_pin	*pin;
++	unsigned int	flags;
++};
++
++/* cpup flags */
++#define AuCpup_DTIME		1		/* do dtime_store/revert */
++#define AuCpup_KEEPLINO		(1 << 1)	/* do not clear the lower xino,
++						   for link(2) */
++#define AuCpup_RENAME		(1 << 2)	/* rename after cpup */
++#define AuCpup_HOPEN		(1 << 3)	/* call h_open_pre/post() in
++						   cpup */
++#define AuCpup_OVERWRITE	(1 << 4)	/* allow overwriting the
++						   existing entry */
++#define AuCpup_RWDST		(1 << 5)	/* force write target even if
++						   the branch is marked as RO */
++
++#define au_ftest_cpup(flags, name)	((flags) & AuCpup_##name)
++#define au_fset_cpup(flags, name) \
++	do { (flags) |= AuCpup_##name; } while (0)
++#define au_fclr_cpup(flags, name) \
++	do { (flags) &= ~AuCpup_##name; } while (0)
++
++int au_copy_file(struct file *dst, struct file *src, loff_t len);
++int au_sio_cpup_simple(struct au_cp_generic *cpg);
++int au_sio_cpdown_simple(struct au_cp_generic *cpg);
++int au_sio_cpup_wh(struct au_cp_generic *cpg, struct file *file);
++
++int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
++	       int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
++			 struct au_pin *pin,
++			 struct dentry *h_parent, void *arg),
++	       void *arg);
++int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
++int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
++
++/* ---------------------------------------------------------------------- */
++
++/* keep timestamps when copyup */
++struct au_dtime {
++	struct dentry *dt_dentry;
++	struct path dt_h_path;
++	struct timespec dt_atime, dt_mtime;
++};
++void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
++		    struct path *h_path);
++void au_dtime_revert(struct au_dtime *dt);
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_CPUP_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/dbgaufs.c linux-4.0.4/fs/aufs/dbgaufs.c
+--- linux-4.0.4.orig/fs/aufs/dbgaufs.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dbgaufs.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,419 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * debugfs interface
++ */
++
++#include <linux/debugfs.h>
++#include "aufs.h"
++
++#ifndef CONFIG_SYSFS
++#error DEBUG_FS depends upon SYSFS
++#endif
++
++static struct dentry *dbgaufs;
++static const mode_t dbgaufs_mode = S_IRUSR | S_IRGRP | S_IROTH;
++
++/* 20 is max digits length of ulong 64 */
++struct dbgaufs_arg {
++	int n;
++	char a[20 * 4];
++};
++
++/*
++ * common function for all XINO files
++ */
++static int dbgaufs_xi_release(struct inode *inode __maybe_unused,
++			      struct file *file)
++{
++	kfree(file->private_data);
++	return 0;
++}
++
++static int dbgaufs_xi_open(struct file *xf, struct file *file, int do_fcnt)
++{
++	int err;
++	struct kstat st;
++	struct dbgaufs_arg *p;
++
++	err = -ENOMEM;
++	p = kmalloc(sizeof(*p), GFP_NOFS);
++	if (unlikely(!p))
++		goto out;
++
++	err = 0;
++	p->n = 0;
++	file->private_data = p;
++	if (!xf)
++		goto out;
++
++	err = vfs_getattr(&xf->f_path, &st);
++	if (!err) {
++		if (do_fcnt)
++			p->n = snprintf
++				(p->a, sizeof(p->a), "%ld, %llux%lu %lld\n",
++				 (long)file_count(xf), st.blocks, st.blksize,
++				 (long long)st.size);
++		else
++			p->n = snprintf(p->a, sizeof(p->a), "%llux%lu %lld\n",
++					st.blocks, st.blksize,
++					(long long)st.size);
++		AuDebugOn(p->n >= sizeof(p->a));
++	} else {
++		p->n = snprintf(p->a, sizeof(p->a), "err %d\n", err);
++		err = 0;
++	}
++
++out:
++	return err;
++
++}
++
++static ssize_t dbgaufs_xi_read(struct file *file, char __user *buf,
++			       size_t count, loff_t *ppos)
++{
++	struct dbgaufs_arg *p;
++
++	p = file->private_data;
++	return simple_read_from_buffer(buf, count, ppos, p->a, p->n);
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct dbgaufs_plink_arg {
++	int n;
++	char a[];
++};
++
++static int dbgaufs_plink_release(struct inode *inode __maybe_unused,
++				 struct file *file)
++{
++	free_page((unsigned long)file->private_data);
++	return 0;
++}
++
++static int dbgaufs_plink_open(struct inode *inode, struct file *file)
++{
++	int err, i, limit;
++	unsigned long n, sum;
++	struct dbgaufs_plink_arg *p;
++	struct au_sbinfo *sbinfo;
++	struct super_block *sb;
++	struct au_sphlhead *sphl;
++
++	err = -ENOMEM;
++	p = (void *)get_zeroed_page(GFP_NOFS);
++	if (unlikely(!p))
++		goto out;
++
++	err = -EFBIG;
++	sbinfo = inode->i_private;
++	sb = sbinfo->si_sb;
++	si_noflush_read_lock(sb);
++	if (au_opt_test(au_mntflags(sb), PLINK)) {
++		limit = PAGE_SIZE - sizeof(p->n);
++
++		/* the number of buckets */
++		n = snprintf(p->a + p->n, limit, "%d\n", AuPlink_NHASH);
++		p->n += n;
++		limit -= n;
++
++		sum = 0;
++		for (i = 0, sphl = sbinfo->si_plink;
++		     i < AuPlink_NHASH;
++		     i++, sphl++) {
++			n = au_sphl_count(sphl);
++			sum += n;
++
++			n = snprintf(p->a + p->n, limit, "%lu ", n);
++			p->n += n;
++			limit -= n;
++			if (unlikely(limit <= 0))
++				goto out_free;
++		}
++		p->a[p->n - 1] = '\n';
++
++		/* the sum of plinks */
++		n = snprintf(p->a + p->n, limit, "%lu\n", sum);
++		p->n += n;
++		limit -= n;
++		if (unlikely(limit <= 0))
++			goto out_free;
++	} else {
++#define str "1\n0\n0\n"
++		p->n = sizeof(str) - 1;
++		strcpy(p->a, str);
++#undef str
++	}
++	si_read_unlock(sb);
++
++	err = 0;
++	file->private_data = p;
++	goto out; /* success */
++
++out_free:
++	free_page((unsigned long)p);
++out:
++	return err;
++}
++
++static ssize_t dbgaufs_plink_read(struct file *file, char __user *buf,
++				  size_t count, loff_t *ppos)
++{
++	struct dbgaufs_plink_arg *p;
++
++	p = file->private_data;
++	return simple_read_from_buffer(buf, count, ppos, p->a, p->n);
++}
++
++static const struct file_operations dbgaufs_plink_fop = {
++	.owner		= THIS_MODULE,
++	.open		= dbgaufs_plink_open,
++	.release	= dbgaufs_plink_release,
++	.read		= dbgaufs_plink_read
++};
++
++/* ---------------------------------------------------------------------- */
++
++static int dbgaufs_xib_open(struct inode *inode, struct file *file)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++	struct super_block *sb;
++
++	sbinfo = inode->i_private;
++	sb = sbinfo->si_sb;
++	si_noflush_read_lock(sb);
++	err = dbgaufs_xi_open(sbinfo->si_xib, file, /*do_fcnt*/0);
++	si_read_unlock(sb);
++	return err;
++}
++
++static const struct file_operations dbgaufs_xib_fop = {
++	.owner		= THIS_MODULE,
++	.open		= dbgaufs_xib_open,
++	.release	= dbgaufs_xi_release,
++	.read		= dbgaufs_xi_read
++};
++
++/* ---------------------------------------------------------------------- */
++
++#define DbgaufsXi_PREFIX "xi"
++
++static int dbgaufs_xino_open(struct inode *inode, struct file *file)
++{
++	int err;
++	long l;
++	struct au_sbinfo *sbinfo;
++	struct super_block *sb;
++	struct file *xf;
++	struct qstr *name;
++
++	err = -ENOENT;
++	xf = NULL;
++	name = &file->f_path.dentry->d_name;
++	if (unlikely(name->len < sizeof(DbgaufsXi_PREFIX)
++		     || memcmp(name->name, DbgaufsXi_PREFIX,
++			       sizeof(DbgaufsXi_PREFIX) - 1)))
++		goto out;
++	err = kstrtol(name->name + sizeof(DbgaufsXi_PREFIX) - 1, 10, &l);
++	if (unlikely(err))
++		goto out;
++
++	sbinfo = inode->i_private;
++	sb = sbinfo->si_sb;
++	si_noflush_read_lock(sb);
++	if (l <= au_sbend(sb)) {
++		xf = au_sbr(sb, (aufs_bindex_t)l)->br_xino.xi_file;
++		err = dbgaufs_xi_open(xf, file, /*do_fcnt*/1);
++	} else
++		err = -ENOENT;
++	si_read_unlock(sb);
++
++out:
++	return err;
++}
++
++static const struct file_operations dbgaufs_xino_fop = {
++	.owner		= THIS_MODULE,
++	.open		= dbgaufs_xino_open,
++	.release	= dbgaufs_xi_release,
++	.read		= dbgaufs_xi_read
++};
++
++void dbgaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
++{
++	aufs_bindex_t bend;
++	struct au_branch *br;
++	struct au_xino_file *xi;
++
++	if (!au_sbi(sb)->si_dbgaufs)
++		return;
++
++	bend = au_sbend(sb);
++	for (; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		xi = &br->br_xino;
++		debugfs_remove(xi->xi_dbgaufs);
++		xi->xi_dbgaufs = NULL;
++	}
++}
++
++void dbgaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
++{
++	struct au_sbinfo *sbinfo;
++	struct dentry *parent;
++	struct au_branch *br;
++	struct au_xino_file *xi;
++	aufs_bindex_t bend;
++	char name[sizeof(DbgaufsXi_PREFIX) + 5]; /* "xi" bindex NULL */
++
++	sbinfo = au_sbi(sb);
++	parent = sbinfo->si_dbgaufs;
++	if (!parent)
++		return;
++
++	bend = au_sbend(sb);
++	for (; bindex <= bend; bindex++) {
++		snprintf(name, sizeof(name), DbgaufsXi_PREFIX "%d", bindex);
++		br = au_sbr(sb, bindex);
++		xi = &br->br_xino;
++		AuDebugOn(xi->xi_dbgaufs);
++		xi->xi_dbgaufs = debugfs_create_file(name, dbgaufs_mode, parent,
++						     sbinfo, &dbgaufs_xino_fop);
++		/* ignore an error */
++		if (unlikely(!xi->xi_dbgaufs))
++			AuWarn1("failed %s under debugfs\n", name);
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_EXPORT
++static int dbgaufs_xigen_open(struct inode *inode, struct file *file)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++	struct super_block *sb;
++
++	sbinfo = inode->i_private;
++	sb = sbinfo->si_sb;
++	si_noflush_read_lock(sb);
++	err = dbgaufs_xi_open(sbinfo->si_xigen, file, /*do_fcnt*/0);
++	si_read_unlock(sb);
++	return err;
++}
++
++static const struct file_operations dbgaufs_xigen_fop = {
++	.owner		= THIS_MODULE,
++	.open		= dbgaufs_xigen_open,
++	.release	= dbgaufs_xi_release,
++	.read		= dbgaufs_xi_read
++};
++
++static int dbgaufs_xigen_init(struct au_sbinfo *sbinfo)
++{
++	int err;
++
++	/*
++	 * This function is a dynamic '__init' function actually,
++	 * so the tiny check for si_rwsem is unnecessary.
++	 */
++	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
++
++	err = -EIO;
++	sbinfo->si_dbgaufs_xigen = debugfs_create_file
++		("xigen", dbgaufs_mode, sbinfo->si_dbgaufs, sbinfo,
++		 &dbgaufs_xigen_fop);
++	if (sbinfo->si_dbgaufs_xigen)
++		err = 0;
++
++	return err;
++}
++#else
++static int dbgaufs_xigen_init(struct au_sbinfo *sbinfo)
++{
++	return 0;
++}
++#endif /* CONFIG_AUFS_EXPORT */
++
++/* ---------------------------------------------------------------------- */
++
++void dbgaufs_si_fin(struct au_sbinfo *sbinfo)
++{
++	/*
++	 * This function is a dynamic '__fin' function actually,
++	 * so the tiny check for si_rwsem is unnecessary.
++	 */
++	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
++
++	debugfs_remove_recursive(sbinfo->si_dbgaufs);
++	sbinfo->si_dbgaufs = NULL;
++	kobject_put(&sbinfo->si_kobj);
++}
++
++int dbgaufs_si_init(struct au_sbinfo *sbinfo)
++{
++	int err;
++	char name[SysaufsSiNameLen];
++
++	/*
++	 * This function is a dynamic '__init' function actually,
++	 * so the tiny check for si_rwsem is unnecessary.
++	 */
++	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
++
++	err = -ENOENT;
++	if (!dbgaufs) {
++		AuErr1("/debug/aufs is uninitialized\n");
++		goto out;
++	}
++
++	err = -EIO;
++	sysaufs_name(sbinfo, name);
++	sbinfo->si_dbgaufs = debugfs_create_dir(name, dbgaufs);
++	if (unlikely(!sbinfo->si_dbgaufs))
++		goto out;
++	kobject_get(&sbinfo->si_kobj);
++
++	sbinfo->si_dbgaufs_xib = debugfs_create_file
++		("xib", dbgaufs_mode, sbinfo->si_dbgaufs, sbinfo,
++		 &dbgaufs_xib_fop);
++	if (unlikely(!sbinfo->si_dbgaufs_xib))
++		goto out_dir;
++
++	sbinfo->si_dbgaufs_plink = debugfs_create_file
++		("plink", dbgaufs_mode, sbinfo->si_dbgaufs, sbinfo,
++		 &dbgaufs_plink_fop);
++	if (unlikely(!sbinfo->si_dbgaufs_plink))
++		goto out_dir;
++
++	err = dbgaufs_xigen_init(sbinfo);
++	if (!err)
++		goto out; /* success */
++
++out_dir:
++	dbgaufs_si_fin(sbinfo);
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void dbgaufs_fin(void)
++{
++	debugfs_remove(dbgaufs);
++}
++
++int __init dbgaufs_init(void)
++{
++	int err;
++
++	err = -EIO;
++	dbgaufs = debugfs_create_dir(AUFS_NAME, NULL);
++	if (dbgaufs)
++		err = 0;
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/dbgaufs.h linux-4.0.4/fs/aufs/dbgaufs.h
+--- linux-4.0.4.orig/fs/aufs/dbgaufs.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dbgaufs.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,35 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * debugfs interface
++ */
++
++#ifndef __DBGAUFS_H__
++#define __DBGAUFS_H__
++
++#ifdef __KERNEL__
++
++struct super_block;
++struct au_sbinfo;
++
++#ifdef CONFIG_DEBUG_FS
++/* dbgaufs.c */
++void dbgaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
++void dbgaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex);
++void dbgaufs_si_fin(struct au_sbinfo *sbinfo);
++int dbgaufs_si_init(struct au_sbinfo *sbinfo);
++void dbgaufs_fin(void);
++int __init dbgaufs_init(void);
++#else
++AuStubVoid(dbgaufs_brs_del, struct super_block *sb, aufs_bindex_t bindex)
++AuStubVoid(dbgaufs_brs_add, struct super_block *sb, aufs_bindex_t bindex)
++AuStubVoid(dbgaufs_si_fin, struct au_sbinfo *sbinfo)
++AuStubInt0(dbgaufs_si_init, struct au_sbinfo *sbinfo)
++AuStubVoid(dbgaufs_fin, void)
++AuStubInt0(__init dbgaufs_init, void)
++#endif /* CONFIG_DEBUG_FS */
++
++#endif /* __KERNEL__ */
++#endif /* __DBGAUFS_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/dcsub.c linux-4.0.4/fs/aufs/dcsub.c
+--- linux-4.0.4.orig/fs/aufs/dcsub.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dcsub.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,211 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * sub-routines for dentry cache
++ */
++
++#include "aufs.h"
++
++static void au_dpage_free(struct au_dpage *dpage)
++{
++	int i;
++	struct dentry **p;
++
++	p = dpage->dentries;
++	for (i = 0; i < dpage->ndentry; i++)
++		dput(*p++);
++	free_page((unsigned long)dpage->dentries);
++}
++
++int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp)
++{
++	int err;
++	void *p;
++
++	err = -ENOMEM;
++	dpages->dpages = kmalloc(sizeof(*dpages->dpages), gfp);
++	if (unlikely(!dpages->dpages))
++		goto out;
++
++	p = (void *)__get_free_page(gfp);
++	if (unlikely(!p))
++		goto out_dpages;
++
++	dpages->dpages[0].ndentry = 0;
++	dpages->dpages[0].dentries = p;
++	dpages->ndpage = 1;
++	return 0; /* success */
++
++out_dpages:
++	kfree(dpages->dpages);
++out:
++	return err;
++}
++
++void au_dpages_free(struct au_dcsub_pages *dpages)
++{
++	int i;
++	struct au_dpage *p;
++
++	p = dpages->dpages;
++	for (i = 0; i < dpages->ndpage; i++)
++		au_dpage_free(p++);
++	kfree(dpages->dpages);
++}
++
++static int au_dpages_append(struct au_dcsub_pages *dpages,
++			    struct dentry *dentry, gfp_t gfp)
++{
++	int err, sz;
++	struct au_dpage *dpage;
++	void *p;
++
++	dpage = dpages->dpages + dpages->ndpage - 1;
++	sz = PAGE_SIZE / sizeof(dentry);
++	if (unlikely(dpage->ndentry >= sz)) {
++		AuLabel(new dpage);
++		err = -ENOMEM;
++		sz = dpages->ndpage * sizeof(*dpages->dpages);
++		p = au_kzrealloc(dpages->dpages, sz,
++				 sz + sizeof(*dpages->dpages), gfp);
++		if (unlikely(!p))
++			goto out;
++
++		dpages->dpages = p;
++		dpage = dpages->dpages + dpages->ndpage;
++		p = (void *)__get_free_page(gfp);
++		if (unlikely(!p))
++			goto out;
++
++		dpage->ndentry = 0;
++		dpage->dentries = p;
++		dpages->ndpage++;
++	}
++
++	AuDebugOn(au_dcount(dentry) <= 0);
++	dpage->dentries[dpage->ndentry++] = dget_dlock(dentry);
++	return 0; /* success */
++
++out:
++	return err;
++}
++
++/* todo: BAD approach */
++/* copied from linux/fs/dcache.c */
++enum d_walk_ret {
++	D_WALK_CONTINUE,
++	D_WALK_QUIT,
++	D_WALK_NORETRY,
++	D_WALK_SKIP,
++};
++
++extern void d_walk(struct dentry *parent, void *data,
++		   enum d_walk_ret (*enter)(void *, struct dentry *),
++		   void (*finish)(void *));
++
++struct ac_dpages_arg {
++	int err;
++	struct au_dcsub_pages *dpages;
++	struct super_block *sb;
++	au_dpages_test test;
++	void *arg;
++};
++
++static enum d_walk_ret au_call_dpages_append(void *_arg, struct dentry *dentry)
++{
++	enum d_walk_ret ret;
++	struct ac_dpages_arg *arg = _arg;
++
++	ret = D_WALK_CONTINUE;
++	if (dentry->d_sb == arg->sb
++	    && !IS_ROOT(dentry)
++	    && au_dcount(dentry) > 0
++	    && au_di(dentry)
++	    && (!arg->test || arg->test(dentry, arg->arg))) {
++		arg->err = au_dpages_append(arg->dpages, dentry, GFP_ATOMIC);
++		if (unlikely(arg->err))
++			ret = D_WALK_QUIT;
++	}
++
++	return ret;
++}
++
++int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
++		   au_dpages_test test, void *arg)
++{
++	struct ac_dpages_arg args = {
++		.err	= 0,
++		.dpages	= dpages,
++		.sb	= root->d_sb,
++		.test	= test,
++		.arg	= arg
++	};
++
++	d_walk(root, &args, au_call_dpages_append, NULL);
++
++	return args.err;
++}
++
++int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
++		       int do_include, au_dpages_test test, void *arg)
++{
++	int err;
++
++	err = 0;
++	write_seqlock(&rename_lock);
++	spin_lock(&dentry->d_lock);
++	if (do_include
++	    && au_dcount(dentry) > 0
++	    && (!test || test(dentry, arg)))
++		err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
++	spin_unlock(&dentry->d_lock);
++	if (unlikely(err))
++		goto out;
++
++	/*
++	 * RCU for vfsmount is unnecessary since this is a traverse in a single
++	 * mount
++	 */
++	while (!IS_ROOT(dentry)) {
++		dentry = dentry->d_parent; /* rename_lock is locked */
++		spin_lock(&dentry->d_lock);
++		if (au_dcount(dentry) > 0
++		    && (!test || test(dentry, arg)))
++			err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
++		spin_unlock(&dentry->d_lock);
++		if (unlikely(err))
++			break;
++	}
++
++out:
++	write_sequnlock(&rename_lock);
++	return err;
++}
++
++static inline int au_dcsub_dpages_aufs(struct dentry *dentry, void *arg)
++{
++	return au_di(dentry) && dentry->d_sb == arg;
++}
++
++int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages,
++			    struct dentry *dentry, int do_include)
++{
++	return au_dcsub_pages_rev(dpages, dentry, do_include,
++				  au_dcsub_dpages_aufs, dentry->d_sb);
++}
++
++int au_test_subdir(struct dentry *d1, struct dentry *d2)
++{
++	struct path path[2] = {
++		{
++			.dentry = d1
++		},
++		{
++			.dentry = d2
++		}
++	};
++
++	return path_is_under(path + 0, path + 1);
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/dcsub.h linux-4.0.4/fs/aufs/dcsub.h
+--- linux-4.0.4.orig/fs/aufs/dcsub.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dcsub.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,119 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * sub-routines for dentry cache
++ */
++
++#ifndef __AUFS_DCSUB_H__
++#define __AUFS_DCSUB_H__
++
++#ifdef __KERNEL__
++
++#include <linux/dcache.h>
++#include <linux/fs.h>
++
++struct au_dpage {
++	int ndentry;
++	struct dentry **dentries;
++};
++
++struct au_dcsub_pages {
++	int ndpage;
++	struct au_dpage *dpages;
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* dcsub.c */
++int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp);
++void au_dpages_free(struct au_dcsub_pages *dpages);
++typedef int (*au_dpages_test)(struct dentry *dentry, void *arg);
++int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
++		   au_dpages_test test, void *arg);
++int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
++		       int do_include, au_dpages_test test, void *arg);
++int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages,
++			    struct dentry *dentry, int do_include);
++int au_test_subdir(struct dentry *d1, struct dentry *d2);
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * todo: in linux-3.13, several similar (but faster) helpers are added to
++ * include/linux/dcache.h. Try them (in the future).
++ */
++
++static inline int au_d_hashed_positive(struct dentry *d)
++{
++	int err;
++	struct inode *inode = d->d_inode;
++
++	err = 0;
++	if (unlikely(d_unhashed(d) || !inode || !inode->i_nlink))
++		err = -ENOENT;
++	return err;
++}
++
++static inline int au_d_linkable(struct dentry *d)
++{
++	int err;
++	struct inode *inode = d->d_inode;
++
++	err = au_d_hashed_positive(d);
++	if (err
++	    && inode
++	    && (inode->i_state & I_LINKABLE))
++		err = 0;
++	return err;
++}
++
++static inline int au_d_alive(struct dentry *d)
++{
++	int err;
++	struct inode *inode;
++
++	err = 0;
++	if (!IS_ROOT(d))
++		err = au_d_hashed_positive(d);
++	else {
++		inode = d->d_inode;
++		if (unlikely(d_unlinked(d) || !inode || !inode->i_nlink))
++			err = -ENOENT;
++	}
++	return err;
++}
++
++static inline int au_alive_dir(struct dentry *d)
++{
++	int err;
++
++	err = au_d_alive(d);
++	if (unlikely(err || IS_DEADDIR(d->d_inode)))
++		err = -ENOENT;
++	return err;
++}
++
++static inline int au_qstreq(struct qstr *a, struct qstr *b)
++{
++	return a->len == b->len
++		&& !memcmp(a->name, b->name, a->len);
++}
++
++/*
++ * by the commit
++ * 360f547 2015-01-25 dcache: let the dentry count go down to zero without
++ *			taking d_lock
++ * the type of d_lockref.count became int, but the inlined function d_count()
++ * still returns unsigned int.
++ * I don't know why. Maybe it is for every d_count() users?
++ * Anyway au_dcount() lives on.
++ */
++static inline int au_dcount(struct dentry *d)
++{
++	return (int)d_count(d);
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DCSUB_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/debug.c linux-4.0.4/fs/aufs/debug.c
+--- linux-4.0.4.orig/fs/aufs/debug.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/debug.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,425 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * debug print functions
++ */
++
++#include "aufs.h"
++
++/* Returns 0, or -errno.  arg is in kp->arg. */
++static int param_atomic_t_set(const char *val, const struct kernel_param *kp)
++{
++	int err, n;
++
++	err = kstrtoint(val, 0, &n);
++	if (!err) {
++		if (n > 0)
++			au_debug_on();
++		else
++			au_debug_off();
++	}
++	return err;
++}
++
++/* Returns length written or -errno.  Buffer is 4k (ie. be short!) */
++static int param_atomic_t_get(char *buffer, const struct kernel_param *kp)
++{
++	atomic_t *a;
++
++	a = kp->arg;
++	return sprintf(buffer, "%d", atomic_read(a));
++}
++
++static struct kernel_param_ops param_ops_atomic_t = {
++	.set = param_atomic_t_set,
++	.get = param_atomic_t_get
++	/* void (*free)(void *arg) */
++};
++
++atomic_t aufs_debug = ATOMIC_INIT(0);
++MODULE_PARM_DESC(debug, "debug print");
++module_param_named(debug, aufs_debug, atomic_t, S_IRUGO | S_IWUSR | S_IWGRP);
++
++DEFINE_MUTEX(au_dbg_mtx);	/* just to serialize the dbg msgs */
++char *au_plevel = KERN_DEBUG;
++#define dpri(fmt, ...) do {					\
++	if ((au_plevel						\
++	     && strcmp(au_plevel, KERN_DEBUG))			\
++	    || au_debug_test())					\
++		printk("%s" fmt, au_plevel, ##__VA_ARGS__);	\
++} while (0)
++
++/* ---------------------------------------------------------------------- */
++
++void au_dpri_whlist(struct au_nhash *whlist)
++{
++	unsigned long ul, n;
++	struct hlist_head *head;
++	struct au_vdir_wh *pos;
++
++	n = whlist->nh_num;
++	head = whlist->nh_head;
++	for (ul = 0; ul < n; ul++) {
++		hlist_for_each_entry(pos, head, wh_hash)
++			dpri("b%d, %.*s, %d\n",
++			     pos->wh_bindex,
++			     pos->wh_str.len, pos->wh_str.name,
++			     pos->wh_str.len);
++		head++;
++	}
++}
++
++void au_dpri_vdir(struct au_vdir *vdir)
++{
++	unsigned long ul;
++	union au_vdir_deblk_p p;
++	unsigned char *o;
++
++	if (!vdir || IS_ERR(vdir)) {
++		dpri("err %ld\n", PTR_ERR(vdir));
++		return;
++	}
++
++	dpri("deblk %u, nblk %lu, deblk %p, last{%lu, %p}, ver %lu\n",
++	     vdir->vd_deblk_sz, vdir->vd_nblk, vdir->vd_deblk,
++	     vdir->vd_last.ul, vdir->vd_last.p.deblk, vdir->vd_version);
++	for (ul = 0; ul < vdir->vd_nblk; ul++) {
++		p.deblk = vdir->vd_deblk[ul];
++		o = p.deblk;
++		dpri("[%lu]: %p\n", ul, o);
++	}
++}
++
++static int do_pri_inode(aufs_bindex_t bindex, struct inode *inode, int hn,
++			struct dentry *wh)
++{
++	char *n = NULL;
++	int l = 0;
++
++	if (!inode || IS_ERR(inode)) {
++		dpri("i%d: err %ld\n", bindex, PTR_ERR(inode));
++		return -1;
++	}
++
++	/* the type of i_blocks depends upon CONFIG_LBDAF */
++	BUILD_BUG_ON(sizeof(inode->i_blocks) != sizeof(unsigned long)
++		     && sizeof(inode->i_blocks) != sizeof(u64));
++	if (wh) {
++		n = (void *)wh->d_name.name;
++		l = wh->d_name.len;
++	}
++
++	dpri("i%d: %p, i%lu, %s, cnt %d, nl %u, 0%o, sz %llu, blk %llu,"
++	     " hn %d, ct %lld, np %lu, st 0x%lx, f 0x%x, v %llu, g %x%s%.*s\n",
++	     bindex, inode,
++	     inode->i_ino, inode->i_sb ? au_sbtype(inode->i_sb) : "??",
++	     atomic_read(&inode->i_count), inode->i_nlink, inode->i_mode,
++	     i_size_read(inode), (unsigned long long)inode->i_blocks,
++	     hn, (long long)timespec_to_ns(&inode->i_ctime) & 0x0ffff,
++	     inode->i_mapping ? inode->i_mapping->nrpages : 0,
++	     inode->i_state, inode->i_flags, inode->i_version,
++	     inode->i_generation,
++	     l ? ", wh " : "", l, n);
++	return 0;
++}
++
++void au_dpri_inode(struct inode *inode)
++{
++	struct au_iinfo *iinfo;
++	aufs_bindex_t bindex;
++	int err, hn;
++
++	err = do_pri_inode(-1, inode, -1, NULL);
++	if (err || !au_test_aufs(inode->i_sb))
++		return;
++
++	iinfo = au_ii(inode);
++	if (!iinfo)
++		return;
++	dpri("i-1: bstart %d, bend %d, gen %d\n",
++	     iinfo->ii_bstart, iinfo->ii_bend, au_iigen(inode, NULL));
++	if (iinfo->ii_bstart < 0)
++		return;
++	hn = 0;
++	for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend; bindex++) {
++		hn = !!au_hn(iinfo->ii_hinode + bindex);
++		do_pri_inode(bindex, iinfo->ii_hinode[0 + bindex].hi_inode, hn,
++			     iinfo->ii_hinode[0 + bindex].hi_whdentry);
++	}
++}
++
++void au_dpri_dalias(struct inode *inode)
++{
++	struct dentry *d;
++
++	spin_lock(&inode->i_lock);
++	hlist_for_each_entry(d, &inode->i_dentry, d_u.d_alias)
++		au_dpri_dentry(d);
++	spin_unlock(&inode->i_lock);
++}
++
++static int do_pri_dentry(aufs_bindex_t bindex, struct dentry *dentry)
++{
++	struct dentry *wh = NULL;
++	int hn;
++	struct au_iinfo *iinfo;
++
++	if (!dentry || IS_ERR(dentry)) {
++		dpri("d%d: err %ld\n", bindex, PTR_ERR(dentry));
++		return -1;
++	}
++	/* do not call dget_parent() here */
++	/* note: access d_xxx without d_lock */
++	dpri("d%d: %p, %pd2?, %s, cnt %d, flags 0x%x, %shashed\n",
++	     bindex, dentry, dentry,
++	     dentry->d_sb ? au_sbtype(dentry->d_sb) : "??",
++	     au_dcount(dentry), dentry->d_flags,
++	     d_unhashed(dentry) ? "un" : "");
++	hn = -1;
++	if (bindex >= 0 && dentry->d_inode && au_test_aufs(dentry->d_sb)) {
++		iinfo = au_ii(dentry->d_inode);
++		if (iinfo) {
++			hn = !!au_hn(iinfo->ii_hinode + bindex);
++			wh = iinfo->ii_hinode[0 + bindex].hi_whdentry;
++		}
++	}
++	do_pri_inode(bindex, dentry->d_inode, hn, wh);
++	return 0;
++}
++
++void au_dpri_dentry(struct dentry *dentry)
++{
++	struct au_dinfo *dinfo;
++	aufs_bindex_t bindex;
++	int err;
++	struct au_hdentry *hdp;
++
++	err = do_pri_dentry(-1, dentry);
++	if (err || !au_test_aufs(dentry->d_sb))
++		return;
++
++	dinfo = au_di(dentry);
++	if (!dinfo)
++		return;
++	dpri("d-1: bstart %d, bend %d, bwh %d, bdiropq %d, gen %d, tmp %d\n",
++	     dinfo->di_bstart, dinfo->di_bend,
++	     dinfo->di_bwh, dinfo->di_bdiropq, au_digen(dentry),
++	     dinfo->di_tmpfile);
++	if (dinfo->di_bstart < 0)
++		return;
++	hdp = dinfo->di_hdentry;
++	for (bindex = dinfo->di_bstart; bindex <= dinfo->di_bend; bindex++)
++		do_pri_dentry(bindex, hdp[0 + bindex].hd_dentry);
++}
++
++static int do_pri_file(aufs_bindex_t bindex, struct file *file)
++{
++	char a[32];
++
++	if (!file || IS_ERR(file)) {
++		dpri("f%d: err %ld\n", bindex, PTR_ERR(file));
++		return -1;
++	}
++	a[0] = 0;
++	if (bindex < 0
++	    && !IS_ERR_OR_NULL(file->f_path.dentry)
++	    && au_test_aufs(file->f_path.dentry->d_sb)
++	    && au_fi(file))
++		snprintf(a, sizeof(a), ", gen %d, mmapped %d",
++			 au_figen(file), atomic_read(&au_fi(file)->fi_mmapped));
++	dpri("f%d: mode 0x%x, flags 0%o, cnt %ld, v %llu, pos %llu%s\n",
++	     bindex, file->f_mode, file->f_flags, (long)file_count(file),
++	     file->f_version, file->f_pos, a);
++	if (!IS_ERR_OR_NULL(file->f_path.dentry))
++		do_pri_dentry(bindex, file->f_path.dentry);
++	return 0;
++}
++
++void au_dpri_file(struct file *file)
++{
++	struct au_finfo *finfo;
++	struct au_fidir *fidir;
++	struct au_hfile *hfile;
++	aufs_bindex_t bindex;
++	int err;
++
++	err = do_pri_file(-1, file);
++	if (err
++	    || IS_ERR_OR_NULL(file->f_path.dentry)
++	    || !au_test_aufs(file->f_path.dentry->d_sb))
++		return;
++
++	finfo = au_fi(file);
++	if (!finfo)
++		return;
++	if (finfo->fi_btop < 0)
++		return;
++	fidir = finfo->fi_hdir;
++	if (!fidir)
++		do_pri_file(finfo->fi_btop, finfo->fi_htop.hf_file);
++	else
++		for (bindex = finfo->fi_btop;
++		     bindex >= 0 && bindex <= fidir->fd_bbot;
++		     bindex++) {
++			hfile = fidir->fd_hfile + bindex;
++			do_pri_file(bindex, hfile ? hfile->hf_file : NULL);
++		}
++}
++
++static int do_pri_br(aufs_bindex_t bindex, struct au_branch *br)
++{
++	struct vfsmount *mnt;
++	struct super_block *sb;
++
++	if (!br || IS_ERR(br))
++		goto out;
++	mnt = au_br_mnt(br);
++	if (!mnt || IS_ERR(mnt))
++		goto out;
++	sb = mnt->mnt_sb;
++	if (!sb || IS_ERR(sb))
++		goto out;
++
++	dpri("s%d: {perm 0x%x, id %d, cnt %d, wbr %p}, "
++	     "%s, dev 0x%02x%02x, flags 0x%lx, cnt %d, active %d, "
++	     "xino %d\n",
++	     bindex, br->br_perm, br->br_id, atomic_read(&br->br_count),
++	     br->br_wbr, au_sbtype(sb), MAJOR(sb->s_dev), MINOR(sb->s_dev),
++	     sb->s_flags, sb->s_count,
++	     atomic_read(&sb->s_active), !!br->br_xino.xi_file);
++	return 0;
++
++out:
++	dpri("s%d: err %ld\n", bindex, PTR_ERR(br));
++	return -1;
++}
++
++void au_dpri_sb(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++	aufs_bindex_t bindex;
++	int err;
++	/* to reuduce stack size */
++	struct {
++		struct vfsmount mnt;
++		struct au_branch fake;
++	} *a;
++
++	/* this function can be called from magic sysrq */
++	a = kzalloc(sizeof(*a), GFP_ATOMIC);
++	if (unlikely(!a)) {
++		dpri("no memory\n");
++		return;
++	}
++
++	a->mnt.mnt_sb = sb;
++	a->fake.br_perm = 0;
++	a->fake.br_path.mnt = &a->mnt;
++	a->fake.br_xino.xi_file = NULL;
++	atomic_set(&a->fake.br_count, 0);
++	smp_mb(); /* atomic_set */
++	err = do_pri_br(-1, &a->fake);
++	kfree(a);
++	dpri("dev 0x%x\n", sb->s_dev);
++	if (err || !au_test_aufs(sb))
++		return;
++
++	sbinfo = au_sbi(sb);
++	if (!sbinfo)
++		return;
++	dpri("nw %d, gen %u, kobj %d\n",
++	     atomic_read(&sbinfo->si_nowait.nw_len), sbinfo->si_generation,
++	     atomic_read(&sbinfo->si_kobj.kref.refcount));
++	for (bindex = 0; bindex <= sbinfo->si_bend; bindex++)
++		do_pri_br(bindex, sbinfo->si_branch[0 + bindex]);
++}
++
++/* ---------------------------------------------------------------------- */
++
++void __au_dbg_verify_dinode(struct dentry *dentry, const char *func, int line)
++{
++	struct inode *h_inode, *inode = dentry->d_inode;
++	struct dentry *h_dentry;
++	aufs_bindex_t bindex, bend, bi;
++
++	if (!inode /* || au_di(dentry)->di_lsc == AuLsc_DI_TMP */)
++		return;
++
++	bend = au_dbend(dentry);
++	bi = au_ibend(inode);
++	if (bi < bend)
++		bend = bi;
++	bindex = au_dbstart(dentry);
++	bi = au_ibstart(inode);
++	if (bi > bindex)
++		bindex = bi;
++
++	for (; bindex <= bend; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++		h_inode = au_h_iptr(inode, bindex);
++		if (unlikely(h_inode != h_dentry->d_inode)) {
++			au_debug_on();
++			AuDbg("b%d, %s:%d\n", bindex, func, line);
++			AuDbgDentry(dentry);
++			AuDbgInode(inode);
++			au_debug_off();
++			BUG();
++		}
++	}
++}
++
++void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen)
++{
++	int err, i, j;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry **dentries;
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	AuDebugOn(err);
++	err = au_dcsub_pages_rev_aufs(&dpages, parent, /*do_include*/1);
++	AuDebugOn(err);
++	for (i = dpages.ndpage - 1; !err && i >= 0; i--) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		for (j = dpage->ndentry - 1; !err && j >= 0; j--)
++			AuDebugOn(au_digen_test(dentries[j], sigen));
++	}
++	au_dpages_free(&dpages);
++}
++
++void au_dbg_verify_kthread(void)
++{
++	if (au_wkq_test()) {
++		au_dbg_blocked();
++		/*
++		 * It may be recursive, but udba=notify between two aufs mounts,
++		 * where a single ro branch is shared, is not a problem.
++		 */
++		/* WARN_ON(1); */
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++int __init au_debug_init(void)
++{
++	aufs_bindex_t bindex;
++	struct au_vdir_destr destr;
++
++	bindex = -1;
++	AuDebugOn(bindex >= 0);
++
++	destr.len = -1;
++	AuDebugOn(destr.len < NAME_MAX);
++
++#ifdef CONFIG_4KSTACKS
++	pr_warn("CONFIG_4KSTACKS is defined.\n");
++#endif
++
++	return 0;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/debug.h linux-4.0.4/fs/aufs/debug.h
+--- linux-4.0.4.orig/fs/aufs/debug.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/debug.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,212 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * debug print functions
++ */
++
++#ifndef __AUFS_DEBUG_H__
++#define __AUFS_DEBUG_H__
++
++#ifdef __KERNEL__
++
++#include <linux/atomic.h>
++#include <linux/module.h>
++#include <linux/kallsyms.h>
++#include <linux/sysrq.h>
++
++#ifdef CONFIG_AUFS_DEBUG
++#define AuDebugOn(a)		BUG_ON(a)
++
++/* module parameter */
++extern atomic_t aufs_debug;
++static inline void au_debug_on(void)
++{
++	atomic_inc(&aufs_debug);
++}
++static inline void au_debug_off(void)
++{
++	atomic_dec_if_positive(&aufs_debug);
++}
++
++static inline int au_debug_test(void)
++{
++	return atomic_read(&aufs_debug) > 0;
++}
++#else
++#define AuDebugOn(a)		do {} while (0)
++AuStubVoid(au_debug_on, void)
++AuStubVoid(au_debug_off, void)
++AuStubInt0(au_debug_test, void)
++#endif /* CONFIG_AUFS_DEBUG */
++
++#define param_check_atomic_t(name, p) __param_check(name, p, atomic_t)
++
++/* ---------------------------------------------------------------------- */
++
++/* debug print */
++
++#define AuDbg(fmt, ...) do { \
++	if (au_debug_test()) \
++		pr_debug("DEBUG: " fmt, ##__VA_ARGS__); \
++} while (0)
++#define AuLabel(l)		AuDbg(#l "\n")
++#define AuIOErr(fmt, ...)	pr_err("I/O Error, " fmt, ##__VA_ARGS__)
++#define AuWarn1(fmt, ...) do { \
++	static unsigned char _c; \
++	if (!_c++) \
++		pr_warn(fmt, ##__VA_ARGS__); \
++} while (0)
++
++#define AuErr1(fmt, ...) do { \
++	static unsigned char _c; \
++	if (!_c++) \
++		pr_err(fmt, ##__VA_ARGS__); \
++} while (0)
++
++#define AuIOErr1(fmt, ...) do { \
++	static unsigned char _c; \
++	if (!_c++) \
++		AuIOErr(fmt, ##__VA_ARGS__); \
++} while (0)
++
++#define AuUnsupportMsg	"This operation is not supported." \
++			" Please report this application to aufs-users ML."
++#define AuUnsupport(fmt, ...) do { \
++	pr_err(AuUnsupportMsg "\n" fmt, ##__VA_ARGS__); \
++	dump_stack(); \
++} while (0)
++
++#define AuTraceErr(e) do { \
++	if (unlikely((e) < 0)) \
++		AuDbg("err %d\n", (int)(e)); \
++} while (0)
++
++#define AuTraceErrPtr(p) do { \
++	if (IS_ERR(p)) \
++		AuDbg("err %ld\n", PTR_ERR(p)); \
++} while (0)
++
++/* dirty macros for debug print, use with "%.*s" and caution */
++#define AuLNPair(qstr)		(qstr)->len, (qstr)->name
++
++/* ---------------------------------------------------------------------- */
++
++struct dentry;
++#ifdef CONFIG_AUFS_DEBUG
++extern struct mutex au_dbg_mtx;
++extern char *au_plevel;
++struct au_nhash;
++void au_dpri_whlist(struct au_nhash *whlist);
++struct au_vdir;
++void au_dpri_vdir(struct au_vdir *vdir);
++struct inode;
++void au_dpri_inode(struct inode *inode);
++void au_dpri_dalias(struct inode *inode);
++void au_dpri_dentry(struct dentry *dentry);
++struct file;
++void au_dpri_file(struct file *filp);
++struct super_block;
++void au_dpri_sb(struct super_block *sb);
++
++#define au_dbg_verify_dinode(d) __au_dbg_verify_dinode(d, __func__, __LINE__)
++void __au_dbg_verify_dinode(struct dentry *dentry, const char *func, int line);
++void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen);
++void au_dbg_verify_kthread(void);
++
++int __init au_debug_init(void);
++
++#define AuDbgWhlist(w) do { \
++	mutex_lock(&au_dbg_mtx); \
++	AuDbg(#w "\n"); \
++	au_dpri_whlist(w); \
++	mutex_unlock(&au_dbg_mtx); \
++} while (0)
++
++#define AuDbgVdir(v) do { \
++	mutex_lock(&au_dbg_mtx); \
++	AuDbg(#v "\n"); \
++	au_dpri_vdir(v); \
++	mutex_unlock(&au_dbg_mtx); \
++} while (0)
++
++#define AuDbgInode(i) do { \
++	mutex_lock(&au_dbg_mtx); \
++	AuDbg(#i "\n"); \
++	au_dpri_inode(i); \
++	mutex_unlock(&au_dbg_mtx); \
++} while (0)
++
++#define AuDbgDAlias(i) do { \
++	mutex_lock(&au_dbg_mtx); \
++	AuDbg(#i "\n"); \
++	au_dpri_dalias(i); \
++	mutex_unlock(&au_dbg_mtx); \
++} while (0)
++
++#define AuDbgDentry(d) do { \
++	mutex_lock(&au_dbg_mtx); \
++	AuDbg(#d "\n"); \
++	au_dpri_dentry(d); \
++	mutex_unlock(&au_dbg_mtx); \
++} while (0)
++
++#define AuDbgFile(f) do { \
++	mutex_lock(&au_dbg_mtx); \
++	AuDbg(#f "\n"); \
++	au_dpri_file(f); \
++	mutex_unlock(&au_dbg_mtx); \
++} while (0)
++
++#define AuDbgSb(sb) do { \
++	mutex_lock(&au_dbg_mtx); \
++	AuDbg(#sb "\n"); \
++	au_dpri_sb(sb); \
++	mutex_unlock(&au_dbg_mtx); \
++} while (0)
++
++#define AuDbgSym(addr) do {				\
++	char sym[KSYM_SYMBOL_LEN];			\
++	sprint_symbol(sym, (unsigned long)addr);	\
++	AuDbg("%s\n", sym);				\
++} while (0)
++#else
++AuStubVoid(au_dbg_verify_dinode, struct dentry *dentry)
++AuStubVoid(au_dbg_verify_gen, struct dentry *parent, unsigned int sigen)
++AuStubVoid(au_dbg_verify_kthread, void)
++AuStubInt0(__init au_debug_init, void)
++
++#define AuDbgWhlist(w)		do {} while (0)
++#define AuDbgVdir(v)		do {} while (0)
++#define AuDbgInode(i)		do {} while (0)
++#define AuDbgDAlias(i)		do {} while (0)
++#define AuDbgDentry(d)		do {} while (0)
++#define AuDbgFile(f)		do {} while (0)
++#define AuDbgSb(sb)		do {} while (0)
++#define AuDbgSym(addr)		do {} while (0)
++#endif /* CONFIG_AUFS_DEBUG */
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_MAGIC_SYSRQ
++int __init au_sysrq_init(void);
++void au_sysrq_fin(void);
++
++#ifdef CONFIG_HW_CONSOLE
++#define au_dbg_blocked() do { \
++	WARN_ON(1); \
++	handle_sysrq('w'); \
++} while (0)
++#else
++AuStubVoid(au_dbg_blocked, void)
++#endif
++
++#else
++AuStubInt0(__init au_sysrq_init, void)
++AuStubVoid(au_sysrq_fin, void)
++AuStubVoid(au_dbg_blocked, void)
++#endif /* CONFIG_AUFS_MAGIC_SYSRQ */
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DEBUG_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/dentry.c linux-4.0.4/fs/aufs/dentry.c
+--- linux-4.0.4.orig/fs/aufs/dentry.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dentry.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,1084 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * lookup and dentry operations
++ */
++
++#include <linux/namei.h>
++#include "aufs.h"
++
++#define AuLkup_ALLOW_NEG	1
++#define AuLkup_IGNORE_PERM	(1 << 1)
++#define au_ftest_lkup(flags, name)	((flags) & AuLkup_##name)
++#define au_fset_lkup(flags, name) \
++	do { (flags) |= AuLkup_##name; } while (0)
++#define au_fclr_lkup(flags, name) \
++	do { (flags) &= ~AuLkup_##name; } while (0)
++
++struct au_do_lookup_args {
++	unsigned int		flags;
++	mode_t			type;
++};
++
++/*
++ * returns positive/negative dentry, NULL or an error.
++ * NULL means whiteout-ed or not-found.
++ */
++static struct dentry*
++au_do_lookup(struct dentry *h_parent, struct dentry *dentry,
++	     aufs_bindex_t bindex, struct qstr *wh_name,
++	     struct au_do_lookup_args *args)
++{
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++	struct au_branch *br;
++	int wh_found, opq;
++	unsigned char wh_able;
++	const unsigned char allow_neg = !!au_ftest_lkup(args->flags, ALLOW_NEG);
++	const unsigned char ignore_perm = !!au_ftest_lkup(args->flags,
++							  IGNORE_PERM);
++
++	wh_found = 0;
++	br = au_sbr(dentry->d_sb, bindex);
++	wh_able = !!au_br_whable(br->br_perm);
++	if (wh_able)
++		wh_found = au_wh_test(h_parent, wh_name, /*try_sio*/0);
++	h_dentry = ERR_PTR(wh_found);
++	if (!wh_found)
++		goto real_lookup;
++	if (unlikely(wh_found < 0))
++		goto out;
++
++	/* We found a whiteout */
++	/* au_set_dbend(dentry, bindex); */
++	au_set_dbwh(dentry, bindex);
++	if (!allow_neg)
++		return NULL; /* success */
++
++real_lookup:
++	if (!ignore_perm)
++		h_dentry = vfsub_lkup_one(&dentry->d_name, h_parent);
++	else
++		h_dentry = au_sio_lkup_one(&dentry->d_name, h_parent);
++	if (IS_ERR(h_dentry)) {
++		if (PTR_ERR(h_dentry) == -ENAMETOOLONG
++		    && !allow_neg)
++			h_dentry = NULL;
++		goto out;
++	}
++
++	h_inode = h_dentry->d_inode;
++	if (!h_inode) {
++		if (!allow_neg)
++			goto out_neg;
++	} else if (wh_found
++		   || (args->type && args->type != (h_inode->i_mode & S_IFMT)))
++		goto out_neg;
++
++	if (au_dbend(dentry) <= bindex)
++		au_set_dbend(dentry, bindex);
++	if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
++		au_set_dbstart(dentry, bindex);
++	au_set_h_dptr(dentry, bindex, h_dentry);
++
++	if (!d_is_dir(h_dentry)
++	    || !wh_able
++	    || (d_is_positive(dentry) && !d_is_dir(dentry)))
++		goto out; /* success */
++
++	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++	opq = au_diropq_test(h_dentry);
++	mutex_unlock(&h_inode->i_mutex);
++	if (opq > 0)
++		au_set_dbdiropq(dentry, bindex);
++	else if (unlikely(opq < 0)) {
++		au_set_h_dptr(dentry, bindex, NULL);
++		h_dentry = ERR_PTR(opq);
++	}
++	goto out;
++
++out_neg:
++	dput(h_dentry);
++	h_dentry = NULL;
++out:
++	return h_dentry;
++}
++
++static int au_test_shwh(struct super_block *sb, const struct qstr *name)
++{
++	if (unlikely(!au_opt_test(au_mntflags(sb), SHWH)
++		     && !strncmp(name->name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)))
++		return -EPERM;
++	return 0;
++}
++
++/*
++ * returns the number of lower positive dentries,
++ * otherwise an error.
++ * can be called at unlinking with @type is zero.
++ */
++int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type)
++{
++	int npositive, err;
++	aufs_bindex_t bindex, btail, bdiropq;
++	unsigned char isdir, dirperm1;
++	struct qstr whname;
++	struct au_do_lookup_args args = {
++		.flags		= 0,
++		.type		= type
++	};
++	const struct qstr *name = &dentry->d_name;
++	struct dentry *parent;
++	struct inode *inode;
++	struct super_block *sb;
++
++	sb = dentry->d_sb;
++	err = au_test_shwh(sb, name);
++	if (unlikely(err))
++		goto out;
++
++	err = au_wh_name_alloc(&whname, name);
++	if (unlikely(err))
++		goto out;
++
++	inode = dentry->d_inode;
++	isdir = !!d_is_dir(dentry);
++	if (!type)
++		au_fset_lkup(args.flags, ALLOW_NEG);
++	dirperm1 = !!au_opt_test(au_mntflags(sb), DIRPERM1);
++
++	npositive = 0;
++	parent = dget_parent(dentry);
++	btail = au_dbtaildir(parent);
++	for (bindex = bstart; bindex <= btail; bindex++) {
++		struct dentry *h_parent, *h_dentry;
++		struct inode *h_inode, *h_dir;
++
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (h_dentry) {
++			if (h_dentry->d_inode)
++				npositive++;
++			if (type != S_IFDIR)
++				break;
++			continue;
++		}
++		h_parent = au_h_dptr(parent, bindex);
++		if (!h_parent || !d_is_dir(h_parent))
++			continue;
++
++		h_dir = h_parent->d_inode;
++		mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
++		h_dentry = au_do_lookup(h_parent, dentry, bindex, &whname,
++					&args);
++		mutex_unlock(&h_dir->i_mutex);
++		err = PTR_ERR(h_dentry);
++		if (IS_ERR(h_dentry))
++			goto out_parent;
++		if (h_dentry)
++			au_fclr_lkup(args.flags, ALLOW_NEG);
++		if (dirperm1)
++			au_fset_lkup(args.flags, IGNORE_PERM);
++
++		if (au_dbwh(dentry) >= 0)
++			break;
++		if (!h_dentry)
++			continue;
++		h_inode = h_dentry->d_inode;
++		if (!h_inode)
++			continue;
++		npositive++;
++		if (!args.type)
++			args.type = h_inode->i_mode & S_IFMT;
++		if (args.type != S_IFDIR)
++			break;
++		else if (isdir) {
++			/* the type of lower may be different */
++			bdiropq = au_dbdiropq(dentry);
++			if (bdiropq >= 0 && bdiropq <= bindex)
++				break;
++		}
++	}
++
++	if (npositive) {
++		AuLabel(positive);
++		au_update_dbstart(dentry);
++	}
++	err = npositive;
++	if (unlikely(!au_opt_test(au_mntflags(sb), UDBA_NONE)
++		     && au_dbstart(dentry) < 0)) {
++		err = -EIO;
++		AuIOErr("both of real entry and whiteout found, %pd, err %d\n",
++			dentry, err);
++	}
++
++out_parent:
++	dput(parent);
++	kfree(whname.name);
++out:
++	return err;
++}
++
++struct dentry *au_sio_lkup_one(struct qstr *name, struct dentry *parent)
++{
++	struct dentry *dentry;
++	int wkq_err;
++
++	if (!au_test_h_perm_sio(parent->d_inode, MAY_EXEC))
++		dentry = vfsub_lkup_one(name, parent);
++	else {
++		struct vfsub_lkup_one_args args = {
++			.errp	= &dentry,
++			.name	= name,
++			.parent	= parent
++		};
++
++		wkq_err = au_wkq_wait(vfsub_call_lkup_one, &args);
++		if (unlikely(wkq_err))
++			dentry = ERR_PTR(wkq_err);
++	}
++
++	return dentry;
++}
++
++/*
++ * lookup @dentry on @bindex which should be negative.
++ */
++int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex, int wh)
++{
++	int err;
++	struct dentry *parent, *h_parent, *h_dentry;
++	struct au_branch *br;
++
++	parent = dget_parent(dentry);
++	h_parent = au_h_dptr(parent, bindex);
++	br = au_sbr(dentry->d_sb, bindex);
++	if (wh)
++		h_dentry = au_whtmp_lkup(h_parent, br, &dentry->d_name);
++	else
++		h_dentry = au_sio_lkup_one(&dentry->d_name, h_parent);
++	err = PTR_ERR(h_dentry);
++	if (IS_ERR(h_dentry))
++		goto out;
++	if (unlikely(h_dentry->d_inode)) {
++		err = -EIO;
++		AuIOErr("%pd should be negative on b%d.\n", h_dentry, bindex);
++		dput(h_dentry);
++		goto out;
++	}
++
++	err = 0;
++	if (bindex < au_dbstart(dentry))
++		au_set_dbstart(dentry, bindex);
++	if (au_dbend(dentry) < bindex)
++		au_set_dbend(dentry, bindex);
++	au_set_h_dptr(dentry, bindex, h_dentry);
++
++out:
++	dput(parent);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* subset of struct inode */
++struct au_iattr {
++	unsigned long		i_ino;
++	/* unsigned int		i_nlink; */
++	kuid_t			i_uid;
++	kgid_t			i_gid;
++	u64			i_version;
++/*
++	loff_t			i_size;
++	blkcnt_t		i_blocks;
++*/
++	umode_t			i_mode;
++};
++
++static void au_iattr_save(struct au_iattr *ia, struct inode *h_inode)
++{
++	ia->i_ino = h_inode->i_ino;
++	/* ia->i_nlink = h_inode->i_nlink; */
++	ia->i_uid = h_inode->i_uid;
++	ia->i_gid = h_inode->i_gid;
++	ia->i_version = h_inode->i_version;
++/*
++	ia->i_size = h_inode->i_size;
++	ia->i_blocks = h_inode->i_blocks;
++*/
++	ia->i_mode = (h_inode->i_mode & S_IFMT);
++}
++
++static int au_iattr_test(struct au_iattr *ia, struct inode *h_inode)
++{
++	return ia->i_ino != h_inode->i_ino
++		/* || ia->i_nlink != h_inode->i_nlink */
++		|| !uid_eq(ia->i_uid, h_inode->i_uid)
++		|| !gid_eq(ia->i_gid, h_inode->i_gid)
++		|| ia->i_version != h_inode->i_version
++/*
++		|| ia->i_size != h_inode->i_size
++		|| ia->i_blocks != h_inode->i_blocks
++*/
++		|| ia->i_mode != (h_inode->i_mode & S_IFMT);
++}
++
++static int au_h_verify_dentry(struct dentry *h_dentry, struct dentry *h_parent,
++			      struct au_branch *br)
++{
++	int err;
++	struct au_iattr ia;
++	struct inode *h_inode;
++	struct dentry *h_d;
++	struct super_block *h_sb;
++
++	err = 0;
++	memset(&ia, -1, sizeof(ia));
++	h_sb = h_dentry->d_sb;
++	h_inode = h_dentry->d_inode;
++	if (h_inode)
++		au_iattr_save(&ia, h_inode);
++	else if (au_test_nfs(h_sb) || au_test_fuse(h_sb))
++		/* nfs d_revalidate may return 0 for negative dentry */
++		/* fuse d_revalidate always return 0 for negative dentry */
++		goto out;
++
++	/* main purpose is namei.c:cached_lookup() and d_revalidate */
++	h_d = vfsub_lkup_one(&h_dentry->d_name, h_parent);
++	err = PTR_ERR(h_d);
++	if (IS_ERR(h_d))
++		goto out;
++
++	err = 0;
++	if (unlikely(h_d != h_dentry
++		     || h_d->d_inode != h_inode
++		     || (h_inode && au_iattr_test(&ia, h_inode))))
++		err = au_busy_or_stale();
++	dput(h_d);
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++int au_h_verify(struct dentry *h_dentry, unsigned int udba, struct inode *h_dir,
++		struct dentry *h_parent, struct au_branch *br)
++{
++	int err;
++
++	err = 0;
++	if (udba == AuOpt_UDBA_REVAL
++	    && !au_test_fs_remote(h_dentry->d_sb)) {
++		IMustLock(h_dir);
++		err = (h_dentry->d_parent->d_inode != h_dir);
++	} else if (udba != AuOpt_UDBA_NONE)
++		err = au_h_verify_dentry(h_dentry, h_parent, br);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_do_refresh_hdentry(struct dentry *dentry, struct dentry *parent)
++{
++	int err;
++	aufs_bindex_t new_bindex, bindex, bend, bwh, bdiropq;
++	struct au_hdentry tmp, *p, *q;
++	struct au_dinfo *dinfo;
++	struct super_block *sb;
++
++	DiMustWriteLock(dentry);
++
++	sb = dentry->d_sb;
++	dinfo = au_di(dentry);
++	bend = dinfo->di_bend;
++	bwh = dinfo->di_bwh;
++	bdiropq = dinfo->di_bdiropq;
++	p = dinfo->di_hdentry + dinfo->di_bstart;
++	for (bindex = dinfo->di_bstart; bindex <= bend; bindex++, p++) {
++		if (!p->hd_dentry)
++			continue;
++
++		new_bindex = au_br_index(sb, p->hd_id);
++		if (new_bindex == bindex)
++			continue;
++
++		if (dinfo->di_bwh == bindex)
++			bwh = new_bindex;
++		if (dinfo->di_bdiropq == bindex)
++			bdiropq = new_bindex;
++		if (new_bindex < 0) {
++			au_hdput(p);
++			p->hd_dentry = NULL;
++			continue;
++		}
++
++		/* swap two lower dentries, and loop again */
++		q = dinfo->di_hdentry + new_bindex;
++		tmp = *q;
++		*q = *p;
++		*p = tmp;
++		if (tmp.hd_dentry) {
++			bindex--;
++			p--;
++		}
++	}
++
++	dinfo->di_bwh = -1;
++	if (bwh >= 0 && bwh <= au_sbend(sb) && au_sbr_whable(sb, bwh))
++		dinfo->di_bwh = bwh;
++
++	dinfo->di_bdiropq = -1;
++	if (bdiropq >= 0
++	    && bdiropq <= au_sbend(sb)
++	    && au_sbr_whable(sb, bdiropq))
++		dinfo->di_bdiropq = bdiropq;
++
++	err = -EIO;
++	dinfo->di_bstart = -1;
++	dinfo->di_bend = -1;
++	bend = au_dbend(parent);
++	p = dinfo->di_hdentry;
++	for (bindex = 0; bindex <= bend; bindex++, p++)
++		if (p->hd_dentry) {
++			dinfo->di_bstart = bindex;
++			break;
++		}
++
++	if (dinfo->di_bstart >= 0) {
++		p = dinfo->di_hdentry + bend;
++		for (bindex = bend; bindex >= 0; bindex--, p--)
++			if (p->hd_dentry) {
++				dinfo->di_bend = bindex;
++				err = 0;
++				break;
++			}
++	}
++
++	return err;
++}
++
++static void au_do_hide(struct dentry *dentry)
++{
++	struct inode *inode;
++
++	inode = dentry->d_inode;
++	if (inode) {
++		if (!S_ISDIR(inode->i_mode)) {
++			if (inode->i_nlink && !d_unhashed(dentry))
++				drop_nlink(inode);
++		} else {
++			clear_nlink(inode);
++			/* stop next lookup */
++			inode->i_flags |= S_DEAD;
++		}
++		smp_mb(); /* necessary? */
++	}
++	d_drop(dentry);
++}
++
++static int au_hide_children(struct dentry *parent)
++{
++	int err, i, j, ndentry;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry *dentry;
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	err = au_dcsub_pages(&dpages, parent, NULL, NULL);
++	if (unlikely(err))
++		goto out_dpages;
++
++	/* in reverse order */
++	for (i = dpages.ndpage - 1; i >= 0; i--) {
++		dpage = dpages.dpages + i;
++		ndentry = dpage->ndentry;
++		for (j = ndentry - 1; j >= 0; j--) {
++			dentry = dpage->dentries[j];
++			if (dentry != parent)
++				au_do_hide(dentry);
++		}
++	}
++
++out_dpages:
++	au_dpages_free(&dpages);
++out:
++	return err;
++}
++
++static void au_hide(struct dentry *dentry)
++{
++	int err;
++
++	AuDbgDentry(dentry);
++	if (d_is_dir(dentry)) {
++		/* shrink_dcache_parent(dentry); */
++		err = au_hide_children(dentry);
++		if (unlikely(err))
++			AuIOErr("%pd, failed hiding children, ignored %d\n",
++				dentry, err);
++	}
++	au_do_hide(dentry);
++}
++
++/*
++ * By adding a dirty branch, a cached dentry may be affected in various ways.
++ *
++ * a dirty branch is added
++ * - on the top of layers
++ * - in the middle of layers
++ * - to the bottom of layers
++ *
++ * on the added branch there exists
++ * - a whiteout
++ * - a diropq
++ * - a same named entry
++ *   + exist
++ *     * negative --> positive
++ *     * positive --> positive
++ *	 - type is unchanged
++ *	 - type is changed
++ *   + doesn't exist
++ *     * negative --> negative
++ *     * positive --> negative (rejected by au_br_del() for non-dir case)
++ * - none
++ */
++static int au_refresh_by_dinfo(struct dentry *dentry, struct au_dinfo *dinfo,
++			       struct au_dinfo *tmp)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	struct {
++		struct dentry *dentry;
++		struct inode *inode;
++		mode_t mode;
++	} orig_h, tmp_h;
++	struct au_hdentry *hd;
++	struct inode *inode, *h_inode;
++	struct dentry *h_dentry;
++
++	err = 0;
++	AuDebugOn(dinfo->di_bstart < 0);
++	orig_h.dentry = dinfo->di_hdentry[dinfo->di_bstart].hd_dentry;
++	orig_h.inode = orig_h.dentry->d_inode;
++	orig_h.mode = 0;
++	if (orig_h.inode)
++		orig_h.mode = orig_h.inode->i_mode & S_IFMT;
++	memset(&tmp_h, 0, sizeof(tmp_h));
++	if (tmp->di_bstart >= 0) {
++		tmp_h.dentry = tmp->di_hdentry[tmp->di_bstart].hd_dentry;
++		tmp_h.inode = tmp_h.dentry->d_inode;
++		if (tmp_h.inode)
++			tmp_h.mode = tmp_h.inode->i_mode & S_IFMT;
++	}
++
++	inode = dentry->d_inode;
++	if (!orig_h.inode) {
++		AuDbg("nagative originally\n");
++		if (inode) {
++			au_hide(dentry);
++			goto out;
++		}
++		AuDebugOn(inode);
++		AuDebugOn(dinfo->di_bstart != dinfo->di_bend);
++		AuDebugOn(dinfo->di_bdiropq != -1);
++
++		if (!tmp_h.inode) {
++			AuDbg("negative --> negative\n");
++			/* should have only one negative lower */
++			if (tmp->di_bstart >= 0
++			    && tmp->di_bstart < dinfo->di_bstart) {
++				AuDebugOn(tmp->di_bstart != tmp->di_bend);
++				AuDebugOn(dinfo->di_bstart != dinfo->di_bend);
++				au_set_h_dptr(dentry, dinfo->di_bstart, NULL);
++				au_di_cp(dinfo, tmp);
++				hd = tmp->di_hdentry + tmp->di_bstart;
++				au_set_h_dptr(dentry, tmp->di_bstart,
++					      dget(hd->hd_dentry));
++			}
++			au_dbg_verify_dinode(dentry);
++		} else {
++			AuDbg("negative --> positive\n");
++			/*
++			 * similar to the behaviour of creating with bypassing
++			 * aufs.
++			 * unhash it in order to force an error in the
++			 * succeeding create operation.
++			 * we should not set S_DEAD here.
++			 */
++			d_drop(dentry);
++			/* au_di_swap(tmp, dinfo); */
++			au_dbg_verify_dinode(dentry);
++		}
++	} else {
++		AuDbg("positive originally\n");
++		/* inode may be NULL */
++		AuDebugOn(inode && (inode->i_mode & S_IFMT) != orig_h.mode);
++		if (!tmp_h.inode) {
++			AuDbg("positive --> negative\n");
++			/* or bypassing aufs */
++			au_hide(dentry);
++			if (tmp->di_bwh >= 0 && tmp->di_bwh <= dinfo->di_bstart)
++				dinfo->di_bwh = tmp->di_bwh;
++			if (inode)
++				err = au_refresh_hinode_self(inode);
++			au_dbg_verify_dinode(dentry);
++		} else if (orig_h.mode == tmp_h.mode) {
++			AuDbg("positive --> positive, same type\n");
++			if (!S_ISDIR(orig_h.mode)
++			    && dinfo->di_bstart > tmp->di_bstart) {
++				/*
++				 * similar to the behaviour of removing and
++				 * creating.
++				 */
++				au_hide(dentry);
++				if (inode)
++					err = au_refresh_hinode_self(inode);
++				au_dbg_verify_dinode(dentry);
++			} else {
++				/* fill empty slots */
++				if (dinfo->di_bstart > tmp->di_bstart)
++					dinfo->di_bstart = tmp->di_bstart;
++				if (dinfo->di_bend < tmp->di_bend)
++					dinfo->di_bend = tmp->di_bend;
++				dinfo->di_bwh = tmp->di_bwh;
++				dinfo->di_bdiropq = tmp->di_bdiropq;
++				hd = tmp->di_hdentry;
++				bend = dinfo->di_bend;
++				for (bindex = tmp->di_bstart; bindex <= bend;
++				     bindex++) {
++					if (au_h_dptr(dentry, bindex))
++						continue;
++					h_dentry = hd[bindex].hd_dentry;
++					if (!h_dentry)
++						continue;
++					h_inode = h_dentry->d_inode;
++					AuDebugOn(!h_inode);
++					AuDebugOn(orig_h.mode
++						  != (h_inode->i_mode
++						      & S_IFMT));
++					au_set_h_dptr(dentry, bindex,
++						      dget(h_dentry));
++				}
++				err = au_refresh_hinode(inode, dentry);
++				au_dbg_verify_dinode(dentry);
++			}
++		} else {
++			AuDbg("positive --> positive, different type\n");
++			/* similar to the behaviour of removing and creating */
++			au_hide(dentry);
++			if (inode)
++				err = au_refresh_hinode_self(inode);
++			au_dbg_verify_dinode(dentry);
++		}
++	}
++
++out:
++	return err;
++}
++
++int au_refresh_dentry(struct dentry *dentry, struct dentry *parent)
++{
++	int err, ebrange;
++	unsigned int sigen;
++	struct au_dinfo *dinfo, *tmp;
++	struct super_block *sb;
++	struct inode *inode;
++
++	DiMustWriteLock(dentry);
++	AuDebugOn(IS_ROOT(dentry));
++	AuDebugOn(!parent->d_inode);
++
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	sigen = au_sigen(sb);
++	err = au_digen_test(parent, sigen);
++	if (unlikely(err))
++		goto out;
++
++	dinfo = au_di(dentry);
++	err = au_di_realloc(dinfo, au_sbend(sb) + 1);
++	if (unlikely(err))
++		goto out;
++	ebrange = au_dbrange_test(dentry);
++	if (!ebrange)
++		ebrange = au_do_refresh_hdentry(dentry, parent);
++
++	if (d_unhashed(dentry) || ebrange /* || dinfo->di_tmpfile */) {
++		AuDebugOn(au_dbstart(dentry) < 0 && au_dbend(dentry) >= 0);
++		if (inode)
++			err = au_refresh_hinode_self(inode);
++		au_dbg_verify_dinode(dentry);
++		if (!err)
++			goto out_dgen; /* success */
++		goto out;
++	}
++
++	/* temporary dinfo */
++	AuDbgDentry(dentry);
++	err = -ENOMEM;
++	tmp = au_di_alloc(sb, AuLsc_DI_TMP);
++	if (unlikely(!tmp))
++		goto out;
++	au_di_swap(tmp, dinfo);
++	/* returns the number of positive dentries */
++	/*
++	 * if current working dir is removed, it returns an error.
++	 * but the dentry is legal.
++	 */
++	err = au_lkup_dentry(dentry, /*bstart*/0, /*type*/0);
++	AuDbgDentry(dentry);
++	au_di_swap(tmp, dinfo);
++	if (err == -ENOENT)
++		err = 0;
++	if (err >= 0) {
++		/* compare/refresh by dinfo */
++		AuDbgDentry(dentry);
++		err = au_refresh_by_dinfo(dentry, dinfo, tmp);
++		au_dbg_verify_dinode(dentry);
++		AuTraceErr(err);
++	}
++	au_rw_write_unlock(&tmp->di_rwsem);
++	au_di_free(tmp);
++	if (unlikely(err))
++		goto out;
++
++out_dgen:
++	au_update_digen(dentry);
++out:
++	if (unlikely(err && !(dentry->d_flags & DCACHE_NFSFS_RENAMED))) {
++		AuIOErr("failed refreshing %pd, %d\n", dentry, err);
++		AuDbgDentry(dentry);
++	}
++	AuTraceErr(err);
++	return err;
++}
++
++static int au_do_h_d_reval(struct dentry *h_dentry, unsigned int flags,
++			   struct dentry *dentry, aufs_bindex_t bindex)
++{
++	int err, valid;
++
++	err = 0;
++	if (!(h_dentry->d_flags & DCACHE_OP_REVALIDATE))
++		goto out;
++
++	AuDbg("b%d\n", bindex);
++	/*
++	 * gave up supporting LOOKUP_CREATE/OPEN for lower fs,
++	 * due to whiteout and branch permission.
++	 */
++	flags &= ~(/*LOOKUP_PARENT |*/ LOOKUP_OPEN | LOOKUP_CREATE
++		   | LOOKUP_FOLLOW | LOOKUP_EXCL);
++	/* it may return tri-state */
++	valid = h_dentry->d_op->d_revalidate(h_dentry, flags);
++
++	if (unlikely(valid < 0))
++		err = valid;
++	else if (!valid)
++		err = -EINVAL;
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* todo: remove this */
++static int h_d_revalidate(struct dentry *dentry, struct inode *inode,
++			  unsigned int flags, int do_udba)
++{
++	int err;
++	umode_t mode, h_mode;
++	aufs_bindex_t bindex, btail, bstart, ibs, ibe;
++	unsigned char plus, unhashed, is_root, h_plus, h_nfs, tmpfile;
++	struct inode *h_inode, *h_cached_inode;
++	struct dentry *h_dentry;
++	struct qstr *name, *h_name;
++
++	err = 0;
++	plus = 0;
++	mode = 0;
++	ibs = -1;
++	ibe = -1;
++	unhashed = !!d_unhashed(dentry);
++	is_root = !!IS_ROOT(dentry);
++	name = &dentry->d_name;
++	tmpfile = au_di(dentry)->di_tmpfile;
++
++	/*
++	 * Theoretically, REVAL test should be unnecessary in case of
++	 * {FS,I}NOTIFY.
++	 * But {fs,i}notify doesn't fire some necessary events,
++	 *	IN_ATTRIB for atime/nlink/pageio
++	 * Let's do REVAL test too.
++	 */
++	if (do_udba && inode) {
++		mode = (inode->i_mode & S_IFMT);
++		plus = (inode->i_nlink > 0);
++		ibs = au_ibstart(inode);
++		ibe = au_ibend(inode);
++	}
++
++	bstart = au_dbstart(dentry);
++	btail = bstart;
++	if (inode && S_ISDIR(inode->i_mode))
++		btail = au_dbtaildir(dentry);
++	for (bindex = bstart; bindex <= btail; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++
++		AuDbg("b%d, %pd\n", bindex, h_dentry);
++		h_nfs = !!au_test_nfs(h_dentry->d_sb);
++		spin_lock(&h_dentry->d_lock);
++		h_name = &h_dentry->d_name;
++		if (unlikely(do_udba
++			     && !is_root
++			     && ((!h_nfs
++				  && (unhashed != !!d_unhashed(h_dentry)
++				      || (!tmpfile
++					  && !au_qstreq(name, h_name))
++					  ))
++				 || (h_nfs
++				     && !(flags & LOOKUP_OPEN)
++				     && (h_dentry->d_flags
++					 & DCACHE_NFSFS_RENAMED)))
++			    )) {
++			int h_unhashed;
++
++			h_unhashed = d_unhashed(h_dentry);
++			spin_unlock(&h_dentry->d_lock);
++			AuDbg("unhash 0x%x 0x%x, %pd %pd\n",
++			      unhashed, h_unhashed, dentry, h_dentry);
++			goto err;
++		}
++		spin_unlock(&h_dentry->d_lock);
++
++		err = au_do_h_d_reval(h_dentry, flags, dentry, bindex);
++		if (unlikely(err))
++			/* do not goto err, to keep the errno */
++			break;
++
++		/* todo: plink too? */
++		if (!do_udba)
++			continue;
++
++		/* UDBA tests */
++		h_inode = h_dentry->d_inode;
++		if (unlikely(!!inode != !!h_inode))
++			goto err;
++
++		h_plus = plus;
++		h_mode = mode;
++		h_cached_inode = h_inode;
++		if (h_inode) {
++			h_mode = (h_inode->i_mode & S_IFMT);
++			h_plus = (h_inode->i_nlink > 0);
++		}
++		if (inode && ibs <= bindex && bindex <= ibe)
++			h_cached_inode = au_h_iptr(inode, bindex);
++
++		if (!h_nfs) {
++			if (unlikely(plus != h_plus && !tmpfile))
++				goto err;
++		} else {
++			if (unlikely(!(h_dentry->d_flags & DCACHE_NFSFS_RENAMED)
++				     && !is_root
++				     && !IS_ROOT(h_dentry)
++				     && unhashed != d_unhashed(h_dentry)))
++				goto err;
++		}
++		if (unlikely(mode != h_mode
++			     || h_cached_inode != h_inode))
++			goto err;
++		continue;
++
++err:
++		err = -EINVAL;
++		break;
++	}
++
++	AuTraceErr(err);
++	return err;
++}
++
++/* todo: consolidate with do_refresh() and au_reval_for_attr() */
++static int simple_reval_dpath(struct dentry *dentry, unsigned int sigen)
++{
++	int err;
++	struct dentry *parent;
++
++	if (!au_digen_test(dentry, sigen))
++		return 0;
++
++	parent = dget_parent(dentry);
++	di_read_lock_parent(parent, AuLock_IR);
++	AuDebugOn(au_digen_test(parent, sigen));
++	au_dbg_verify_gen(parent, sigen);
++	err = au_refresh_dentry(dentry, parent);
++	di_read_unlock(parent, AuLock_IR);
++	dput(parent);
++	AuTraceErr(err);
++	return err;
++}
++
++int au_reval_dpath(struct dentry *dentry, unsigned int sigen)
++{
++	int err;
++	struct dentry *d, *parent;
++	struct inode *inode;
++
++	if (!au_ftest_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIR))
++		return simple_reval_dpath(dentry, sigen);
++
++	/* slow loop, keep it simple and stupid */
++	/* cf: au_cpup_dirs() */
++	err = 0;
++	parent = NULL;
++	while (au_digen_test(dentry, sigen)) {
++		d = dentry;
++		while (1) {
++			dput(parent);
++			parent = dget_parent(d);
++			if (!au_digen_test(parent, sigen))
++				break;
++			d = parent;
++		}
++
++		inode = d->d_inode;
++		if (d != dentry)
++			di_write_lock_child2(d);
++
++		/* someone might update our dentry while we were sleeping */
++		if (au_digen_test(d, sigen)) {
++			/*
++			 * todo: consolidate with simple_reval_dpath(),
++			 * do_refresh() and au_reval_for_attr().
++			 */
++			di_read_lock_parent(parent, AuLock_IR);
++			err = au_refresh_dentry(d, parent);
++			di_read_unlock(parent, AuLock_IR);
++		}
++
++		if (d != dentry)
++			di_write_unlock(d);
++		dput(parent);
++		if (unlikely(err))
++			break;
++	}
++
++	return err;
++}
++
++/*
++ * if valid returns 1, otherwise 0.
++ */
++static int aufs_d_revalidate(struct dentry *dentry, unsigned int flags)
++{
++	int valid, err;
++	unsigned int sigen;
++	unsigned char do_udba;
++	struct super_block *sb;
++	struct inode *inode;
++
++	/* todo: support rcu-walk? */
++	if (flags & LOOKUP_RCU)
++		return -ECHILD;
++
++	valid = 0;
++	if (unlikely(!au_di(dentry)))
++		goto out;
++
++	valid = 1;
++	sb = dentry->d_sb;
++	/*
++	 * todo: very ugly
++	 * i_mutex of parent dir may be held,
++	 * but we should not return 'invalid' due to busy.
++	 */
++	err = aufs_read_lock(dentry, AuLock_FLUSH | AuLock_DW | AuLock_NOPLM);
++	if (unlikely(err)) {
++		valid = err;
++		AuTraceErr(err);
++		goto out;
++	}
++	inode = dentry->d_inode;
++	if (unlikely(inode && is_bad_inode(inode))) {
++		err = -EINVAL;
++		AuTraceErr(err);
++		goto out_dgrade;
++	}
++	if (unlikely(au_dbrange_test(dentry))) {
++		err = -EINVAL;
++		AuTraceErr(err);
++		goto out_dgrade;
++	}
++
++	sigen = au_sigen(sb);
++	if (au_digen_test(dentry, sigen)) {
++		AuDebugOn(IS_ROOT(dentry));
++		err = au_reval_dpath(dentry, sigen);
++		if (unlikely(err)) {
++			AuTraceErr(err);
++			goto out_dgrade;
++		}
++	}
++	di_downgrade_lock(dentry, AuLock_IR);
++
++	err = -EINVAL;
++	if (!(flags & (LOOKUP_OPEN | LOOKUP_EMPTY))
++	    && inode
++	    && !(inode->i_state && I_LINKABLE)
++	    && (IS_DEADDIR(inode) || !inode->i_nlink))
++		goto out_inval;
++
++	do_udba = !au_opt_test(au_mntflags(sb), UDBA_NONE);
++	if (do_udba && inode) {
++		aufs_bindex_t bstart = au_ibstart(inode);
++		struct inode *h_inode;
++
++		if (bstart >= 0) {
++			h_inode = au_h_iptr(inode, bstart);
++			if (h_inode && au_test_higen(inode, h_inode))
++				goto out_inval;
++		}
++	}
++
++	err = h_d_revalidate(dentry, inode, flags, do_udba);
++	if (unlikely(!err && do_udba && au_dbstart(dentry) < 0)) {
++		err = -EIO;
++		AuDbg("both of real entry and whiteout found, %p, err %d\n",
++		      dentry, err);
++	}
++	goto out_inval;
++
++out_dgrade:
++	di_downgrade_lock(dentry, AuLock_IR);
++out_inval:
++	aufs_read_unlock(dentry, AuLock_IR);
++	AuTraceErr(err);
++	valid = !err;
++out:
++	if (!valid) {
++		AuDbg("%pd invalid, %d\n", dentry, valid);
++		d_drop(dentry);
++	}
++	return valid;
++}
++
++static void aufs_d_release(struct dentry *dentry)
++{
++	if (au_di(dentry)) {
++		au_di_fin(dentry);
++		au_hn_di_reinit(dentry);
++	}
++}
++
++const struct dentry_operations aufs_dop = {
++	.d_revalidate		= aufs_d_revalidate,
++	.d_weak_revalidate	= aufs_d_revalidate,
++	.d_release		= aufs_d_release
++};
+diff -Nur linux-4.0.4.orig/fs/aufs/dentry.h linux-4.0.4/fs/aufs/dentry.h
+--- linux-4.0.4.orig/fs/aufs/dentry.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dentry.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,220 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * lookup and dentry operations
++ */
++
++#ifndef __AUFS_DENTRY_H__
++#define __AUFS_DENTRY_H__
++
++#ifdef __KERNEL__
++
++#include <linux/dcache.h>
++#include "rwsem.h"
++
++struct au_hdentry {
++	struct dentry		*hd_dentry;
++	aufs_bindex_t		hd_id;
++};
++
++struct au_dinfo {
++	atomic_t		di_generation;
++
++	struct au_rwsem		di_rwsem;
++	aufs_bindex_t		di_bstart, di_bend, di_bwh, di_bdiropq;
++	unsigned char		di_tmpfile; /* to allow the different name */
++	struct au_hdentry	*di_hdentry;
++} ____cacheline_aligned_in_smp;
++
++/* ---------------------------------------------------------------------- */
++
++/* dentry.c */
++extern const struct dentry_operations aufs_dop;
++struct au_branch;
++struct dentry *au_sio_lkup_one(struct qstr *name, struct dentry *parent);
++int au_h_verify(struct dentry *h_dentry, unsigned int udba, struct inode *h_dir,
++		struct dentry *h_parent, struct au_branch *br);
++
++int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type);
++int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex, int wh);
++int au_refresh_dentry(struct dentry *dentry, struct dentry *parent);
++int au_reval_dpath(struct dentry *dentry, unsigned int sigen);
++
++/* dinfo.c */
++void au_di_init_once(void *_di);
++struct au_dinfo *au_di_alloc(struct super_block *sb, unsigned int lsc);
++void au_di_free(struct au_dinfo *dinfo);
++void au_di_swap(struct au_dinfo *a, struct au_dinfo *b);
++void au_di_cp(struct au_dinfo *dst, struct au_dinfo *src);
++int au_di_init(struct dentry *dentry);
++void au_di_fin(struct dentry *dentry);
++int au_di_realloc(struct au_dinfo *dinfo, int nbr);
++
++void di_read_lock(struct dentry *d, int flags, unsigned int lsc);
++void di_read_unlock(struct dentry *d, int flags);
++void di_downgrade_lock(struct dentry *d, int flags);
++void di_write_lock(struct dentry *d, unsigned int lsc);
++void di_write_unlock(struct dentry *d);
++void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir);
++void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir);
++void di_write_unlock2(struct dentry *d1, struct dentry *d2);
++
++struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex);
++struct dentry *au_h_d_alias(struct dentry *dentry, aufs_bindex_t bindex);
++aufs_bindex_t au_dbtail(struct dentry *dentry);
++aufs_bindex_t au_dbtaildir(struct dentry *dentry);
++
++void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
++		   struct dentry *h_dentry);
++int au_digen_test(struct dentry *dentry, unsigned int sigen);
++int au_dbrange_test(struct dentry *dentry);
++void au_update_digen(struct dentry *dentry);
++void au_update_dbrange(struct dentry *dentry, int do_put_zero);
++void au_update_dbstart(struct dentry *dentry);
++void au_update_dbend(struct dentry *dentry);
++int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry);
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct au_dinfo *au_di(struct dentry *dentry)
++{
++	return dentry->d_fsdata;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* lock subclass for dinfo */
++enum {
++	AuLsc_DI_CHILD,		/* child first */
++	AuLsc_DI_CHILD2,	/* rename(2), link(2), and cpup at hnotify */
++	AuLsc_DI_CHILD3,	/* copyup dirs */
++	AuLsc_DI_PARENT,
++	AuLsc_DI_PARENT2,
++	AuLsc_DI_PARENT3,
++	AuLsc_DI_TMP		/* temp for replacing dinfo */
++};
++
++/*
++ * di_read_lock_child, di_write_lock_child,
++ * di_read_lock_child2, di_write_lock_child2,
++ * di_read_lock_child3, di_write_lock_child3,
++ * di_read_lock_parent, di_write_lock_parent,
++ * di_read_lock_parent2, di_write_lock_parent2,
++ * di_read_lock_parent3, di_write_lock_parent3,
++ */
++#define AuReadLockFunc(name, lsc) \
++static inline void di_read_lock_##name(struct dentry *d, int flags) \
++{ di_read_lock(d, flags, AuLsc_DI_##lsc); }
++
++#define AuWriteLockFunc(name, lsc) \
++static inline void di_write_lock_##name(struct dentry *d) \
++{ di_write_lock(d, AuLsc_DI_##lsc); }
++
++#define AuRWLockFuncs(name, lsc) \
++	AuReadLockFunc(name, lsc) \
++	AuWriteLockFunc(name, lsc)
++
++AuRWLockFuncs(child, CHILD);
++AuRWLockFuncs(child2, CHILD2);
++AuRWLockFuncs(child3, CHILD3);
++AuRWLockFuncs(parent, PARENT);
++AuRWLockFuncs(parent2, PARENT2);
++AuRWLockFuncs(parent3, PARENT3);
++
++#undef AuReadLockFunc
++#undef AuWriteLockFunc
++#undef AuRWLockFuncs
++
++#define DiMustNoWaiters(d)	AuRwMustNoWaiters(&au_di(d)->di_rwsem)
++#define DiMustAnyLock(d)	AuRwMustAnyLock(&au_di(d)->di_rwsem)
++#define DiMustWriteLock(d)	AuRwMustWriteLock(&au_di(d)->di_rwsem)
++
++/* ---------------------------------------------------------------------- */
++
++/* todo: memory barrier? */
++static inline unsigned int au_digen(struct dentry *d)
++{
++	return atomic_read(&au_di(d)->di_generation);
++}
++
++static inline void au_h_dentry_init(struct au_hdentry *hdentry)
++{
++	hdentry->hd_dentry = NULL;
++}
++
++static inline void au_hdput(struct au_hdentry *hd)
++{
++	if (hd)
++		dput(hd->hd_dentry);
++}
++
++static inline aufs_bindex_t au_dbstart(struct dentry *dentry)
++{
++	DiMustAnyLock(dentry);
++	return au_di(dentry)->di_bstart;
++}
++
++static inline aufs_bindex_t au_dbend(struct dentry *dentry)
++{
++	DiMustAnyLock(dentry);
++	return au_di(dentry)->di_bend;
++}
++
++static inline aufs_bindex_t au_dbwh(struct dentry *dentry)
++{
++	DiMustAnyLock(dentry);
++	return au_di(dentry)->di_bwh;
++}
++
++static inline aufs_bindex_t au_dbdiropq(struct dentry *dentry)
++{
++	DiMustAnyLock(dentry);
++	return au_di(dentry)->di_bdiropq;
++}
++
++/* todo: hard/soft set? */
++static inline void au_set_dbstart(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	DiMustWriteLock(dentry);
++	au_di(dentry)->di_bstart = bindex;
++}
++
++static inline void au_set_dbend(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	DiMustWriteLock(dentry);
++	au_di(dentry)->di_bend = bindex;
++}
++
++static inline void au_set_dbwh(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	DiMustWriteLock(dentry);
++	/* dbwh can be outside of bstart - bend range */
++	au_di(dentry)->di_bwh = bindex;
++}
++
++static inline void au_set_dbdiropq(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	DiMustWriteLock(dentry);
++	au_di(dentry)->di_bdiropq = bindex;
++}
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_HNOTIFY
++static inline void au_digen_dec(struct dentry *d)
++{
++	atomic_dec(&au_di(d)->di_generation);
++}
++
++static inline void au_hn_di_reinit(struct dentry *dentry)
++{
++	dentry->d_fsdata = NULL;
++}
++#else
++AuStubVoid(au_hn_di_reinit, struct dentry *dentry __maybe_unused)
++#endif /* CONFIG_AUFS_HNOTIFY */
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DENTRY_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/dinfo.c linux-4.0.4/fs/aufs/dinfo.c
+--- linux-4.0.4.orig/fs/aufs/dinfo.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dinfo.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,531 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * dentry private data
++ */
++
++#include "aufs.h"
++
++void au_di_init_once(void *_dinfo)
++{
++	struct au_dinfo *dinfo = _dinfo;
++	static struct lock_class_key aufs_di;
++
++	au_rw_init(&dinfo->di_rwsem);
++	au_rw_class(&dinfo->di_rwsem, &aufs_di);
++}
++
++struct au_dinfo *au_di_alloc(struct super_block *sb, unsigned int lsc)
++{
++	struct au_dinfo *dinfo;
++	int nbr, i;
++
++	dinfo = au_cache_alloc_dinfo();
++	if (unlikely(!dinfo))
++		goto out;
++
++	nbr = au_sbend(sb) + 1;
++	if (nbr <= 0)
++		nbr = 1;
++	dinfo->di_hdentry = kcalloc(nbr, sizeof(*dinfo->di_hdentry), GFP_NOFS);
++	if (dinfo->di_hdentry) {
++		au_rw_write_lock_nested(&dinfo->di_rwsem, lsc);
++		dinfo->di_bstart = -1;
++		dinfo->di_bend = -1;
++		dinfo->di_bwh = -1;
++		dinfo->di_bdiropq = -1;
++		dinfo->di_tmpfile = 0;
++		for (i = 0; i < nbr; i++)
++			dinfo->di_hdentry[i].hd_id = -1;
++		goto out;
++	}
++
++	au_cache_free_dinfo(dinfo);
++	dinfo = NULL;
++
++out:
++	return dinfo;
++}
++
++void au_di_free(struct au_dinfo *dinfo)
++{
++	struct au_hdentry *p;
++	aufs_bindex_t bend, bindex;
++
++	/* dentry may not be revalidated */
++	bindex = dinfo->di_bstart;
++	if (bindex >= 0) {
++		bend = dinfo->di_bend;
++		p = dinfo->di_hdentry + bindex;
++		while (bindex++ <= bend)
++			au_hdput(p++);
++	}
++	kfree(dinfo->di_hdentry);
++	au_cache_free_dinfo(dinfo);
++}
++
++void au_di_swap(struct au_dinfo *a, struct au_dinfo *b)
++{
++	struct au_hdentry *p;
++	aufs_bindex_t bi;
++
++	AuRwMustWriteLock(&a->di_rwsem);
++	AuRwMustWriteLock(&b->di_rwsem);
++
++#define DiSwap(v, name)				\
++	do {					\
++		v = a->di_##name;		\
++		a->di_##name = b->di_##name;	\
++		b->di_##name = v;		\
++	} while (0)
++
++	DiSwap(p, hdentry);
++	DiSwap(bi, bstart);
++	DiSwap(bi, bend);
++	DiSwap(bi, bwh);
++	DiSwap(bi, bdiropq);
++	/* smp_mb(); */
++
++#undef DiSwap
++}
++
++void au_di_cp(struct au_dinfo *dst, struct au_dinfo *src)
++{
++	AuRwMustWriteLock(&dst->di_rwsem);
++	AuRwMustWriteLock(&src->di_rwsem);
++
++	dst->di_bstart = src->di_bstart;
++	dst->di_bend = src->di_bend;
++	dst->di_bwh = src->di_bwh;
++	dst->di_bdiropq = src->di_bdiropq;
++	/* smp_mb(); */
++}
++
++int au_di_init(struct dentry *dentry)
++{
++	int err;
++	struct super_block *sb;
++	struct au_dinfo *dinfo;
++
++	err = 0;
++	sb = dentry->d_sb;
++	dinfo = au_di_alloc(sb, AuLsc_DI_CHILD);
++	if (dinfo) {
++		atomic_set(&dinfo->di_generation, au_sigen(sb));
++		/* smp_mb(); */ /* atomic_set */
++		dentry->d_fsdata = dinfo;
++	} else
++		err = -ENOMEM;
++
++	return err;
++}
++
++void au_di_fin(struct dentry *dentry)
++{
++	struct au_dinfo *dinfo;
++
++	dinfo = au_di(dentry);
++	AuRwDestroy(&dinfo->di_rwsem);
++	au_di_free(dinfo);
++}
++
++int au_di_realloc(struct au_dinfo *dinfo, int nbr)
++{
++	int err, sz;
++	struct au_hdentry *hdp;
++
++	AuRwMustWriteLock(&dinfo->di_rwsem);
++
++	err = -ENOMEM;
++	sz = sizeof(*hdp) * (dinfo->di_bend + 1);
++	if (!sz)
++		sz = sizeof(*hdp);
++	hdp = au_kzrealloc(dinfo->di_hdentry, sz, sizeof(*hdp) * nbr, GFP_NOFS);
++	if (hdp) {
++		dinfo->di_hdentry = hdp;
++		err = 0;
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void do_ii_write_lock(struct inode *inode, unsigned int lsc)
++{
++	switch (lsc) {
++	case AuLsc_DI_CHILD:
++		ii_write_lock_child(inode);
++		break;
++	case AuLsc_DI_CHILD2:
++		ii_write_lock_child2(inode);
++		break;
++	case AuLsc_DI_CHILD3:
++		ii_write_lock_child3(inode);
++		break;
++	case AuLsc_DI_PARENT:
++		ii_write_lock_parent(inode);
++		break;
++	case AuLsc_DI_PARENT2:
++		ii_write_lock_parent2(inode);
++		break;
++	case AuLsc_DI_PARENT3:
++		ii_write_lock_parent3(inode);
++		break;
++	default:
++		BUG();
++	}
++}
++
++static void do_ii_read_lock(struct inode *inode, unsigned int lsc)
++{
++	switch (lsc) {
++	case AuLsc_DI_CHILD:
++		ii_read_lock_child(inode);
++		break;
++	case AuLsc_DI_CHILD2:
++		ii_read_lock_child2(inode);
++		break;
++	case AuLsc_DI_CHILD3:
++		ii_read_lock_child3(inode);
++		break;
++	case AuLsc_DI_PARENT:
++		ii_read_lock_parent(inode);
++		break;
++	case AuLsc_DI_PARENT2:
++		ii_read_lock_parent2(inode);
++		break;
++	case AuLsc_DI_PARENT3:
++		ii_read_lock_parent3(inode);
++		break;
++	default:
++		BUG();
++	}
++}
++
++void di_read_lock(struct dentry *d, int flags, unsigned int lsc)
++{
++	au_rw_read_lock_nested(&au_di(d)->di_rwsem, lsc);
++	if (d->d_inode) {
++		if (au_ftest_lock(flags, IW))
++			do_ii_write_lock(d->d_inode, lsc);
++		else if (au_ftest_lock(flags, IR))
++			do_ii_read_lock(d->d_inode, lsc);
++	}
++}
++
++void di_read_unlock(struct dentry *d, int flags)
++{
++	if (d->d_inode) {
++		if (au_ftest_lock(flags, IW)) {
++			au_dbg_verify_dinode(d);
++			ii_write_unlock(d->d_inode);
++		} else if (au_ftest_lock(flags, IR)) {
++			au_dbg_verify_dinode(d);
++			ii_read_unlock(d->d_inode);
++		}
++	}
++	au_rw_read_unlock(&au_di(d)->di_rwsem);
++}
++
++void di_downgrade_lock(struct dentry *d, int flags)
++{
++	if (d->d_inode && au_ftest_lock(flags, IR))
++		ii_downgrade_lock(d->d_inode);
++	au_rw_dgrade_lock(&au_di(d)->di_rwsem);
++}
++
++void di_write_lock(struct dentry *d, unsigned int lsc)
++{
++	au_rw_write_lock_nested(&au_di(d)->di_rwsem, lsc);
++	if (d->d_inode)
++		do_ii_write_lock(d->d_inode, lsc);
++}
++
++void di_write_unlock(struct dentry *d)
++{
++	au_dbg_verify_dinode(d);
++	if (d->d_inode)
++		ii_write_unlock(d->d_inode);
++	au_rw_write_unlock(&au_di(d)->di_rwsem);
++}
++
++void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir)
++{
++	AuDebugOn(d1 == d2
++		  || d1->d_inode == d2->d_inode
++		  || d1->d_sb != d2->d_sb);
++
++	if (isdir && au_test_subdir(d1, d2)) {
++		di_write_lock_child(d1);
++		di_write_lock_child2(d2);
++	} else {
++		/* there should be no races */
++		di_write_lock_child(d2);
++		di_write_lock_child2(d1);
++	}
++}
++
++void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir)
++{
++	AuDebugOn(d1 == d2
++		  || d1->d_inode == d2->d_inode
++		  || d1->d_sb != d2->d_sb);
++
++	if (isdir && au_test_subdir(d1, d2)) {
++		di_write_lock_parent(d1);
++		di_write_lock_parent2(d2);
++	} else {
++		/* there should be no races */
++		di_write_lock_parent(d2);
++		di_write_lock_parent2(d1);
++	}
++}
++
++void di_write_unlock2(struct dentry *d1, struct dentry *d2)
++{
++	di_write_unlock(d1);
++	if (d1->d_inode == d2->d_inode)
++		au_rw_write_unlock(&au_di(d2)->di_rwsem);
++	else
++		di_write_unlock(d2);
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	struct dentry *d;
++
++	DiMustAnyLock(dentry);
++
++	if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
++		return NULL;
++	AuDebugOn(bindex < 0);
++	d = au_di(dentry)->di_hdentry[0 + bindex].hd_dentry;
++	AuDebugOn(d && au_dcount(d) <= 0);
++	return d;
++}
++
++/*
++ * extended version of au_h_dptr().
++ * returns a hashed and positive (or linkable) h_dentry in bindex, NULL, or
++ * error.
++ */
++struct dentry *au_h_d_alias(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	struct dentry *h_dentry;
++	struct inode *inode, *h_inode;
++
++	inode = dentry->d_inode;
++	AuDebugOn(!inode);
++
++	h_dentry = NULL;
++	if (au_dbstart(dentry) <= bindex
++	    && bindex <= au_dbend(dentry))
++		h_dentry = au_h_dptr(dentry, bindex);
++	if (h_dentry && !au_d_linkable(h_dentry)) {
++		dget(h_dentry);
++		goto out; /* success */
++	}
++
++	AuDebugOn(bindex < au_ibstart(inode));
++	AuDebugOn(au_ibend(inode) < bindex);
++	h_inode = au_h_iptr(inode, bindex);
++	h_dentry = d_find_alias(h_inode);
++	if (h_dentry) {
++		if (!IS_ERR(h_dentry)) {
++			if (!au_d_linkable(h_dentry))
++				goto out; /* success */
++			dput(h_dentry);
++		} else
++			goto out;
++	}
++
++	if (au_opt_test(au_mntflags(dentry->d_sb), PLINK)) {
++		h_dentry = au_plink_lkup(inode, bindex);
++		AuDebugOn(!h_dentry);
++		if (!IS_ERR(h_dentry)) {
++			if (!au_d_hashed_positive(h_dentry))
++				goto out; /* success */
++			dput(h_dentry);
++			h_dentry = NULL;
++		}
++	}
++
++out:
++	AuDbgDentry(h_dentry);
++	return h_dentry;
++}
++
++aufs_bindex_t au_dbtail(struct dentry *dentry)
++{
++	aufs_bindex_t bend, bwh;
++
++	bend = au_dbend(dentry);
++	if (0 <= bend) {
++		bwh = au_dbwh(dentry);
++		if (!bwh)
++			return bwh;
++		if (0 < bwh && bwh < bend)
++			return bwh - 1;
++	}
++	return bend;
++}
++
++aufs_bindex_t au_dbtaildir(struct dentry *dentry)
++{
++	aufs_bindex_t bend, bopq;
++
++	bend = au_dbtail(dentry);
++	if (0 <= bend) {
++		bopq = au_dbdiropq(dentry);
++		if (0 <= bopq && bopq < bend)
++			bend = bopq;
++	}
++	return bend;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
++		   struct dentry *h_dentry)
++{
++	struct au_hdentry *hd = au_di(dentry)->di_hdentry + bindex;
++	struct au_branch *br;
++
++	DiMustWriteLock(dentry);
++
++	au_hdput(hd);
++	hd->hd_dentry = h_dentry;
++	if (h_dentry) {
++		br = au_sbr(dentry->d_sb, bindex);
++		hd->hd_id = br->br_id;
++	}
++}
++
++int au_dbrange_test(struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bstart, bend;
++
++	err = 0;
++	bstart = au_dbstart(dentry);
++	bend = au_dbend(dentry);
++	if (bstart >= 0)
++		AuDebugOn(bend < 0 && bstart > bend);
++	else {
++		err = -EIO;
++		AuDebugOn(bend >= 0);
++	}
++
++	return err;
++}
++
++int au_digen_test(struct dentry *dentry, unsigned int sigen)
++{
++	int err;
++
++	err = 0;
++	if (unlikely(au_digen(dentry) != sigen
++		     || au_iigen_test(dentry->d_inode, sigen)))
++		err = -EIO;
++
++	return err;
++}
++
++void au_update_digen(struct dentry *dentry)
++{
++	atomic_set(&au_di(dentry)->di_generation, au_sigen(dentry->d_sb));
++	/* smp_mb(); */ /* atomic_set */
++}
++
++void au_update_dbrange(struct dentry *dentry, int do_put_zero)
++{
++	struct au_dinfo *dinfo;
++	struct dentry *h_d;
++	struct au_hdentry *hdp;
++
++	DiMustWriteLock(dentry);
++
++	dinfo = au_di(dentry);
++	if (!dinfo || dinfo->di_bstart < 0)
++		return;
++
++	hdp = dinfo->di_hdentry;
++	if (do_put_zero) {
++		aufs_bindex_t bindex, bend;
++
++		bend = dinfo->di_bend;
++		for (bindex = dinfo->di_bstart; bindex <= bend; bindex++) {
++			h_d = hdp[0 + bindex].hd_dentry;
++			if (h_d && !h_d->d_inode)
++				au_set_h_dptr(dentry, bindex, NULL);
++		}
++	}
++
++	dinfo->di_bstart = -1;
++	while (++dinfo->di_bstart <= dinfo->di_bend)
++		if (hdp[0 + dinfo->di_bstart].hd_dentry)
++			break;
++	if (dinfo->di_bstart > dinfo->di_bend) {
++		dinfo->di_bstart = -1;
++		dinfo->di_bend = -1;
++		return;
++	}
++
++	dinfo->di_bend++;
++	while (0 <= --dinfo->di_bend)
++		if (hdp[0 + dinfo->di_bend].hd_dentry)
++			break;
++	AuDebugOn(dinfo->di_bstart > dinfo->di_bend || dinfo->di_bend < 0);
++}
++
++void au_update_dbstart(struct dentry *dentry)
++{
++	aufs_bindex_t bindex, bend;
++	struct dentry *h_dentry;
++
++	bend = au_dbend(dentry);
++	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++		if (h_dentry->d_inode) {
++			au_set_dbstart(dentry, bindex);
++			return;
++		}
++		au_set_h_dptr(dentry, bindex, NULL);
++	}
++}
++
++void au_update_dbend(struct dentry *dentry)
++{
++	aufs_bindex_t bindex, bstart;
++	struct dentry *h_dentry;
++
++	bstart = au_dbstart(dentry);
++	for (bindex = au_dbend(dentry); bindex >= bstart; bindex--) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++		if (h_dentry->d_inode) {
++			au_set_dbend(dentry, bindex);
++			return;
++		}
++		au_set_h_dptr(dentry, bindex, NULL);
++	}
++}
++
++int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry)
++{
++	aufs_bindex_t bindex, bend;
++
++	bend = au_dbend(dentry);
++	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++)
++		if (au_h_dptr(dentry, bindex) == h_dentry)
++			return bindex;
++	return -1;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/dir.c linux-4.0.4/fs/aufs/dir.c
+--- linux-4.0.4.orig/fs/aufs/dir.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dir.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,738 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * directory operations
++ */
++
++#include <linux/fs_stack.h>
++#include "aufs.h"
++
++void au_add_nlink(struct inode *dir, struct inode *h_dir)
++{
++	unsigned int nlink;
++
++	AuDebugOn(!S_ISDIR(dir->i_mode) || !S_ISDIR(h_dir->i_mode));
++
++	nlink = dir->i_nlink;
++	nlink += h_dir->i_nlink - 2;
++	if (h_dir->i_nlink < 2)
++		nlink += 2;
++	smp_mb(); /* for i_nlink */
++	/* 0 can happen in revaliding */
++	set_nlink(dir, nlink);
++}
++
++void au_sub_nlink(struct inode *dir, struct inode *h_dir)
++{
++	unsigned int nlink;
++
++	AuDebugOn(!S_ISDIR(dir->i_mode) || !S_ISDIR(h_dir->i_mode));
++
++	nlink = dir->i_nlink;
++	nlink -= h_dir->i_nlink - 2;
++	if (h_dir->i_nlink < 2)
++		nlink -= 2;
++	smp_mb(); /* for i_nlink */
++	/* nlink == 0 means the branch-fs is broken */
++	set_nlink(dir, nlink);
++}
++
++loff_t au_dir_size(struct file *file, struct dentry *dentry)
++{
++	loff_t sz;
++	aufs_bindex_t bindex, bend;
++	struct file *h_file;
++	struct dentry *h_dentry;
++
++	sz = 0;
++	if (file) {
++		AuDebugOn(!d_is_dir(file->f_path.dentry));
++
++		bend = au_fbend_dir(file);
++		for (bindex = au_fbstart(file);
++		     bindex <= bend && sz < KMALLOC_MAX_SIZE;
++		     bindex++) {
++			h_file = au_hf_dir(file, bindex);
++			if (h_file && file_inode(h_file))
++				sz += vfsub_f_size_read(h_file);
++		}
++	} else {
++		AuDebugOn(!dentry);
++		AuDebugOn(!d_is_dir(dentry));
++
++		bend = au_dbtaildir(dentry);
++		for (bindex = au_dbstart(dentry);
++		     bindex <= bend && sz < KMALLOC_MAX_SIZE;
++		     bindex++) {
++			h_dentry = au_h_dptr(dentry, bindex);
++			if (h_dentry && h_dentry->d_inode)
++				sz += i_size_read(h_dentry->d_inode);
++		}
++	}
++	if (sz < KMALLOC_MAX_SIZE)
++		sz = roundup_pow_of_two(sz);
++	if (sz > KMALLOC_MAX_SIZE)
++		sz = KMALLOC_MAX_SIZE;
++	else if (sz < NAME_MAX) {
++		BUILD_BUG_ON(AUFS_RDBLK_DEF < NAME_MAX);
++		sz = AUFS_RDBLK_DEF;
++	}
++	return sz;
++}
++
++struct au_dir_ts_arg {
++	struct dentry *dentry;
++	aufs_bindex_t brid;
++};
++
++static void au_do_dir_ts(void *arg)
++{
++	struct au_dir_ts_arg *a = arg;
++	struct au_dtime dt;
++	struct path h_path;
++	struct inode *dir, *h_dir;
++	struct super_block *sb;
++	struct au_branch *br;
++	struct au_hinode *hdir;
++	int err;
++	aufs_bindex_t bstart, bindex;
++
++	sb = a->dentry->d_sb;
++	dir = a->dentry->d_inode;
++	if (!dir)
++		goto out;
++	/* no dir->i_mutex lock */
++	aufs_read_lock(a->dentry, AuLock_DW | AuLock_DIR); /* noflush */
++
++	bstart = au_ibstart(dir);
++	bindex = au_br_index(sb, a->brid);
++	if (bindex < bstart)
++		goto out_unlock;
++
++	br = au_sbr(sb, bindex);
++	h_path.dentry = au_h_dptr(a->dentry, bindex);
++	if (!h_path.dentry)
++		goto out_unlock;
++	h_path.mnt = au_br_mnt(br);
++	au_dtime_store(&dt, a->dentry, &h_path);
++
++	br = au_sbr(sb, bstart);
++	if (!au_br_writable(br->br_perm))
++		goto out_unlock;
++	h_path.dentry = au_h_dptr(a->dentry, bstart);
++	h_path.mnt = au_br_mnt(br);
++	err = vfsub_mnt_want_write(h_path.mnt);
++	if (err)
++		goto out_unlock;
++	hdir = au_hi(dir, bstart);
++	au_hn_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++	h_dir = au_h_iptr(dir, bstart);
++	if (h_dir->i_nlink
++	    && timespec_compare(&h_dir->i_mtime, &dt.dt_mtime) < 0) {
++		dt.dt_h_path = h_path;
++		au_dtime_revert(&dt);
++	}
++	au_hn_imtx_unlock(hdir);
++	vfsub_mnt_drop_write(h_path.mnt);
++	au_cpup_attr_timesizes(dir);
++
++out_unlock:
++	aufs_read_unlock(a->dentry, AuLock_DW);
++out:
++	dput(a->dentry);
++	au_nwt_done(&au_sbi(sb)->si_nowait);
++	kfree(arg);
++}
++
++void au_dir_ts(struct inode *dir, aufs_bindex_t bindex)
++{
++	int perm, wkq_err;
++	aufs_bindex_t bstart;
++	struct au_dir_ts_arg *arg;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	IMustLock(dir);
++
++	dentry = d_find_any_alias(dir);
++	AuDebugOn(!dentry);
++	sb = dentry->d_sb;
++	bstart = au_ibstart(dir);
++	if (bstart == bindex) {
++		au_cpup_attr_timesizes(dir);
++		goto out;
++	}
++
++	perm = au_sbr_perm(sb, bstart);
++	if (!au_br_writable(perm))
++		goto out;
++
++	arg = kmalloc(sizeof(*arg), GFP_NOFS);
++	if (!arg)
++		goto out;
++
++	arg->dentry = dget(dentry); /* will be dput-ted by au_do_dir_ts() */
++	arg->brid = au_sbr_id(sb, bindex);
++	wkq_err = au_wkq_nowait(au_do_dir_ts, arg, sb, /*flags*/0);
++	if (unlikely(wkq_err)) {
++		pr_err("wkq %d\n", wkq_err);
++		dput(dentry);
++		kfree(arg);
++	}
++
++out:
++	dput(dentry);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int reopen_dir(struct file *file)
++{
++	int err;
++	unsigned int flags;
++	aufs_bindex_t bindex, btail, bstart;
++	struct dentry *dentry, *h_dentry;
++	struct file *h_file;
++
++	/* open all lower dirs */
++	dentry = file->f_path.dentry;
++	bstart = au_dbstart(dentry);
++	for (bindex = au_fbstart(file); bindex < bstart; bindex++)
++		au_set_h_fptr(file, bindex, NULL);
++	au_set_fbstart(file, bstart);
++
++	btail = au_dbtaildir(dentry);
++	for (bindex = au_fbend_dir(file); btail < bindex; bindex--)
++		au_set_h_fptr(file, bindex, NULL);
++	au_set_fbend_dir(file, btail);
++
++	flags = vfsub_file_flags(file);
++	for (bindex = bstart; bindex <= btail; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++		h_file = au_hf_dir(file, bindex);
++		if (h_file)
++			continue;
++
++		h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
++		err = PTR_ERR(h_file);
++		if (IS_ERR(h_file))
++			goto out; /* close all? */
++		au_set_h_fptr(file, bindex, h_file);
++	}
++	au_update_figen(file);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++	err = 0;
++
++out:
++	return err;
++}
++
++static int do_open_dir(struct file *file, int flags, struct file *h_file)
++{
++	int err;
++	aufs_bindex_t bindex, btail;
++	struct dentry *dentry, *h_dentry;
++
++	FiMustWriteLock(file);
++	AuDebugOn(h_file);
++
++	err = 0;
++	dentry = file->f_path.dentry;
++	file->f_version = dentry->d_inode->i_version;
++	bindex = au_dbstart(dentry);
++	au_set_fbstart(file, bindex);
++	btail = au_dbtaildir(dentry);
++	au_set_fbend_dir(file, btail);
++	for (; !err && bindex <= btail; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (!h_dentry)
++			continue;
++
++		h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
++		if (IS_ERR(h_file)) {
++			err = PTR_ERR(h_file);
++			break;
++		}
++		au_set_h_fptr(file, bindex, h_file);
++	}
++	au_update_figen(file);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++	if (!err)
++		return 0; /* success */
++
++	/* close all */
++	for (bindex = au_fbstart(file); bindex <= btail; bindex++)
++		au_set_h_fptr(file, bindex, NULL);
++	au_set_fbstart(file, -1);
++	au_set_fbend_dir(file, -1);
++
++	return err;
++}
++
++static int aufs_open_dir(struct inode *inode __maybe_unused,
++			 struct file *file)
++{
++	int err;
++	struct super_block *sb;
++	struct au_fidir *fidir;
++
++	err = -ENOMEM;
++	sb = file->f_path.dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	fidir = au_fidir_alloc(sb);
++	if (fidir) {
++		struct au_do_open_args args = {
++			.open	= do_open_dir,
++			.fidir	= fidir
++		};
++		err = au_do_open(file, &args);
++		if (unlikely(err))
++			kfree(fidir);
++	}
++	si_read_unlock(sb);
++	return err;
++}
++
++static int aufs_release_dir(struct inode *inode __maybe_unused,
++			    struct file *file)
++{
++	struct au_vdir *vdir_cache;
++	struct au_finfo *finfo;
++	struct au_fidir *fidir;
++	aufs_bindex_t bindex, bend;
++
++	finfo = au_fi(file);
++	fidir = finfo->fi_hdir;
++	if (fidir) {
++		au_sphl_del(&finfo->fi_hlist,
++			    &au_sbi(file->f_path.dentry->d_sb)->si_files);
++		vdir_cache = fidir->fd_vdir_cache; /* lock-free */
++		if (vdir_cache)
++			au_vdir_free(vdir_cache);
++
++		bindex = finfo->fi_btop;
++		if (bindex >= 0) {
++			/*
++			 * calls fput() instead of filp_close(),
++			 * since no dnotify or lock for the lower file.
++			 */
++			bend = fidir->fd_bbot;
++			for (; bindex <= bend; bindex++)
++				au_set_h_fptr(file, bindex, NULL);
++		}
++		kfree(fidir);
++		finfo->fi_hdir = NULL;
++	}
++	au_finfo_fin(file);
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_do_flush_dir(struct file *file, fl_owner_t id)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	struct file *h_file;
++
++	err = 0;
++	bend = au_fbend_dir(file);
++	for (bindex = au_fbstart(file); !err && bindex <= bend; bindex++) {
++		h_file = au_hf_dir(file, bindex);
++		if (h_file)
++			err = vfsub_flush(h_file, id);
++	}
++	return err;
++}
++
++static int aufs_flush_dir(struct file *file, fl_owner_t id)
++{
++	return au_do_flush(file, id, au_do_flush_dir);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_do_fsync_dir_no_file(struct dentry *dentry, int datasync)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct inode *inode;
++	struct super_block *sb;
++
++	err = 0;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	IMustLock(inode);
++	bend = au_dbend(dentry);
++	for (bindex = au_dbstart(dentry); !err && bindex <= bend; bindex++) {
++		struct path h_path;
++
++		if (au_test_ro(sb, bindex, inode))
++			continue;
++		h_path.dentry = au_h_dptr(dentry, bindex);
++		if (!h_path.dentry)
++			continue;
++
++		h_path.mnt = au_sbr_mnt(sb, bindex);
++		err = vfsub_fsync(NULL, &h_path, datasync);
++	}
++
++	return err;
++}
++
++static int au_do_fsync_dir(struct file *file, int datasync)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct file *h_file;
++	struct super_block *sb;
++	struct inode *inode;
++
++	err = au_reval_and_lock_fdi(file, reopen_dir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	sb = file->f_path.dentry->d_sb;
++	inode = file_inode(file);
++	bend = au_fbend_dir(file);
++	for (bindex = au_fbstart(file); !err && bindex <= bend; bindex++) {
++		h_file = au_hf_dir(file, bindex);
++		if (!h_file || au_test_ro(sb, bindex, inode))
++			continue;
++
++		err = vfsub_fsync(h_file, &h_file->f_path, datasync);
++	}
++
++out:
++	return err;
++}
++
++/*
++ * @file may be NULL
++ */
++static int aufs_fsync_dir(struct file *file, loff_t start, loff_t end,
++			  int datasync)
++{
++	int err;
++	struct dentry *dentry;
++	struct super_block *sb;
++	struct mutex *mtx;
++
++	err = 0;
++	dentry = file->f_path.dentry;
++	mtx = &dentry->d_inode->i_mutex;
++	mutex_lock(mtx);
++	sb = dentry->d_sb;
++	si_noflush_read_lock(sb);
++	if (file)
++		err = au_do_fsync_dir(file, datasync);
++	else {
++		di_write_lock_child(dentry);
++		err = au_do_fsync_dir_no_file(dentry, datasync);
++	}
++	au_cpup_attr_timesizes(dentry->d_inode);
++	di_write_unlock(dentry);
++	if (file)
++		fi_write_unlock(file);
++
++	si_read_unlock(sb);
++	mutex_unlock(mtx);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int aufs_iterate(struct file *file, struct dir_context *ctx)
++{
++	int err;
++	struct dentry *dentry;
++	struct inode *inode, *h_inode;
++	struct super_block *sb;
++
++	AuDbg("%pD, ctx{%pf, %llu}\n", file, ctx->actor, ctx->pos);
++
++	dentry = file->f_path.dentry;
++	inode = dentry->d_inode;
++	IMustLock(inode);
++
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_reval_and_lock_fdi(file, reopen_dir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++	err = au_alive_dir(dentry);
++	if (!err)
++		err = au_vdir_init(file);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err))
++		goto out_unlock;
++
++	h_inode = au_h_iptr(inode, au_ibstart(inode));
++	if (!au_test_nfsd()) {
++		err = au_vdir_fill_de(file, ctx);
++		fsstack_copy_attr_atime(inode, h_inode);
++	} else {
++		/*
++		 * nfsd filldir may call lookup_one_len(), vfs_getattr(),
++		 * encode_fh() and others.
++		 */
++		atomic_inc(&h_inode->i_count);
++		di_read_unlock(dentry, AuLock_IR);
++		si_read_unlock(sb);
++		err = au_vdir_fill_de(file, ctx);
++		fsstack_copy_attr_atime(inode, h_inode);
++		fi_write_unlock(file);
++		iput(h_inode);
++
++		AuTraceErr(err);
++		return err;
++	}
++
++out_unlock:
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++out:
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++#define AuTestEmpty_WHONLY	1
++#define AuTestEmpty_CALLED	(1 << 1)
++#define AuTestEmpty_SHWH	(1 << 2)
++#define au_ftest_testempty(flags, name)	((flags) & AuTestEmpty_##name)
++#define au_fset_testempty(flags, name) \
++	do { (flags) |= AuTestEmpty_##name; } while (0)
++#define au_fclr_testempty(flags, name) \
++	do { (flags) &= ~AuTestEmpty_##name; } while (0)
++
++#ifndef CONFIG_AUFS_SHWH
++#undef AuTestEmpty_SHWH
++#define AuTestEmpty_SHWH	0
++#endif
++
++struct test_empty_arg {
++	struct dir_context ctx;
++	struct au_nhash *whlist;
++	unsigned int flags;
++	int err;
++	aufs_bindex_t bindex;
++};
++
++static int test_empty_cb(struct dir_context *ctx, const char *__name,
++			 int namelen, loff_t offset __maybe_unused, u64 ino,
++			 unsigned int d_type)
++{
++	struct test_empty_arg *arg = container_of(ctx, struct test_empty_arg,
++						  ctx);
++	char *name = (void *)__name;
++
++	arg->err = 0;
++	au_fset_testempty(arg->flags, CALLED);
++	/* smp_mb(); */
++	if (name[0] == '.'
++	    && (namelen == 1 || (name[1] == '.' && namelen == 2)))
++		goto out; /* success */
++
++	if (namelen <= AUFS_WH_PFX_LEN
++	    || memcmp(name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
++		if (au_ftest_testempty(arg->flags, WHONLY)
++		    && !au_nhash_test_known_wh(arg->whlist, name, namelen))
++			arg->err = -ENOTEMPTY;
++		goto out;
++	}
++
++	name += AUFS_WH_PFX_LEN;
++	namelen -= AUFS_WH_PFX_LEN;
++	if (!au_nhash_test_known_wh(arg->whlist, name, namelen))
++		arg->err = au_nhash_append_wh
++			(arg->whlist, name, namelen, ino, d_type, arg->bindex,
++			 au_ftest_testempty(arg->flags, SHWH));
++
++out:
++	/* smp_mb(); */
++	AuTraceErr(arg->err);
++	return arg->err;
++}
++
++static int do_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
++{
++	int err;
++	struct file *h_file;
++
++	h_file = au_h_open(dentry, arg->bindex,
++			   O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_LARGEFILE,
++			   /*file*/NULL, /*force_wr*/0);
++	err = PTR_ERR(h_file);
++	if (IS_ERR(h_file))
++		goto out;
++
++	err = 0;
++	if (!au_opt_test(au_mntflags(dentry->d_sb), UDBA_NONE)
++	    && !file_inode(h_file)->i_nlink)
++		goto out_put;
++
++	do {
++		arg->err = 0;
++		au_fclr_testempty(arg->flags, CALLED);
++		/* smp_mb(); */
++		err = vfsub_iterate_dir(h_file, &arg->ctx);
++		if (err >= 0)
++			err = arg->err;
++	} while (!err && au_ftest_testempty(arg->flags, CALLED));
++
++out_put:
++	fput(h_file);
++	au_sbr_put(dentry->d_sb, arg->bindex);
++out:
++	return err;
++}
++
++struct do_test_empty_args {
++	int *errp;
++	struct dentry *dentry;
++	struct test_empty_arg *arg;
++};
++
++static void call_do_test_empty(void *args)
++{
++	struct do_test_empty_args *a = args;
++	*a->errp = do_test_empty(a->dentry, a->arg);
++}
++
++static int sio_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
++{
++	int err, wkq_err;
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++
++	h_dentry = au_h_dptr(dentry, arg->bindex);
++	h_inode = h_dentry->d_inode;
++	/* todo: i_mode changes anytime? */
++	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++	err = au_test_h_perm_sio(h_inode, MAY_EXEC | MAY_READ);
++	mutex_unlock(&h_inode->i_mutex);
++	if (!err)
++		err = do_test_empty(dentry, arg);
++	else {
++		struct do_test_empty_args args = {
++			.errp	= &err,
++			.dentry	= dentry,
++			.arg	= arg
++		};
++		unsigned int flags = arg->flags;
++
++		wkq_err = au_wkq_wait(call_do_test_empty, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++		arg->flags = flags;
++	}
++
++	return err;
++}
++
++int au_test_empty_lower(struct dentry *dentry)
++{
++	int err;
++	unsigned int rdhash;
++	aufs_bindex_t bindex, bstart, btail;
++	struct au_nhash whlist;
++	struct test_empty_arg arg = {
++		.ctx = {
++			.actor = test_empty_cb
++		}
++	};
++	int (*test_empty)(struct dentry *dentry, struct test_empty_arg *arg);
++
++	SiMustAnyLock(dentry->d_sb);
++
++	rdhash = au_sbi(dentry->d_sb)->si_rdhash;
++	if (!rdhash)
++		rdhash = au_rdhash_est(au_dir_size(/*file*/NULL, dentry));
++	err = au_nhash_alloc(&whlist, rdhash, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++
++	arg.flags = 0;
++	arg.whlist = &whlist;
++	bstart = au_dbstart(dentry);
++	if (au_opt_test(au_mntflags(dentry->d_sb), SHWH))
++		au_fset_testempty(arg.flags, SHWH);
++	test_empty = do_test_empty;
++	if (au_opt_test(au_mntflags(dentry->d_sb), DIRPERM1))
++		test_empty = sio_test_empty;
++	arg.bindex = bstart;
++	err = test_empty(dentry, &arg);
++	if (unlikely(err))
++		goto out_whlist;
++
++	au_fset_testempty(arg.flags, WHONLY);
++	btail = au_dbtaildir(dentry);
++	for (bindex = bstart + 1; !err && bindex <= btail; bindex++) {
++		struct dentry *h_dentry;
++
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (h_dentry && h_dentry->d_inode) {
++			arg.bindex = bindex;
++			err = test_empty(dentry, &arg);
++		}
++	}
++
++out_whlist:
++	au_nhash_wh_free(&whlist);
++out:
++	return err;
++}
++
++int au_test_empty(struct dentry *dentry, struct au_nhash *whlist)
++{
++	int err;
++	struct test_empty_arg arg = {
++		.ctx = {
++			.actor = test_empty_cb
++		}
++	};
++	aufs_bindex_t bindex, btail;
++
++	err = 0;
++	arg.whlist = whlist;
++	arg.flags = AuTestEmpty_WHONLY;
++	if (au_opt_test(au_mntflags(dentry->d_sb), SHWH))
++		au_fset_testempty(arg.flags, SHWH);
++	btail = au_dbtaildir(dentry);
++	for (bindex = au_dbstart(dentry); !err && bindex <= btail; bindex++) {
++		struct dentry *h_dentry;
++
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (h_dentry && h_dentry->d_inode) {
++			arg.bindex = bindex;
++			err = sio_test_empty(dentry, &arg);
++		}
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++const struct file_operations aufs_dir_fop = {
++	.owner		= THIS_MODULE,
++	.llseek		= default_llseek,
++	.read		= generic_read_dir,
++	.iterate	= aufs_iterate,
++	.unlocked_ioctl	= aufs_ioctl_dir,
++#ifdef CONFIG_COMPAT
++	.compat_ioctl	= aufs_compat_ioctl_dir,
++#endif
++	.open		= aufs_open_dir,
++	.release	= aufs_release_dir,
++	.flush		= aufs_flush_dir,
++	.fsync		= aufs_fsync_dir
++};
+diff -Nur linux-4.0.4.orig/fs/aufs/dir.h linux-4.0.4/fs/aufs/dir.h
+--- linux-4.0.4.orig/fs/aufs/dir.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dir.h	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,118 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * directory operations
++ */
++
++#ifndef __AUFS_DIR_H__
++#define __AUFS_DIR_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++
++/* ---------------------------------------------------------------------- */
++
++/* need to be faster and smaller */
++
++struct au_nhash {
++	unsigned int		nh_num;
++	struct hlist_head	*nh_head;
++};
++
++struct au_vdir_destr {
++	unsigned char	len;
++	unsigned char	name[0];
++} __packed;
++
++struct au_vdir_dehstr {
++	struct hlist_node	hash;
++	struct au_vdir_destr	*str;
++} ____cacheline_aligned_in_smp;
++
++struct au_vdir_de {
++	ino_t			de_ino;
++	unsigned char		de_type;
++	/* caution: packed */
++	struct au_vdir_destr	de_str;
++} __packed;
++
++struct au_vdir_wh {
++	struct hlist_node	wh_hash;
++#ifdef CONFIG_AUFS_SHWH
++	ino_t			wh_ino;
++	aufs_bindex_t		wh_bindex;
++	unsigned char		wh_type;
++#else
++	aufs_bindex_t		wh_bindex;
++#endif
++	/* caution: packed */
++	struct au_vdir_destr	wh_str;
++} __packed;
++
++union au_vdir_deblk_p {
++	unsigned char		*deblk;
++	struct au_vdir_de	*de;
++};
++
++struct au_vdir {
++	unsigned char	**vd_deblk;
++	unsigned long	vd_nblk;
++	struct {
++		unsigned long		ul;
++		union au_vdir_deblk_p	p;
++	} vd_last;
++
++	unsigned long	vd_version;
++	unsigned int	vd_deblk_sz;
++	unsigned long	vd_jiffy;
++} ____cacheline_aligned_in_smp;
++
++/* ---------------------------------------------------------------------- */
++
++/* dir.c */
++extern const struct file_operations aufs_dir_fop;
++void au_add_nlink(struct inode *dir, struct inode *h_dir);
++void au_sub_nlink(struct inode *dir, struct inode *h_dir);
++loff_t au_dir_size(struct file *file, struct dentry *dentry);
++void au_dir_ts(struct inode *dir, aufs_bindex_t bsrc);
++int au_test_empty_lower(struct dentry *dentry);
++int au_test_empty(struct dentry *dentry, struct au_nhash *whlist);
++
++/* vdir.c */
++unsigned int au_rdhash_est(loff_t sz);
++int au_nhash_alloc(struct au_nhash *nhash, unsigned int num_hash, gfp_t gfp);
++void au_nhash_wh_free(struct au_nhash *whlist);
++int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
++			    int limit);
++int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int nlen);
++int au_nhash_append_wh(struct au_nhash *whlist, char *name, int nlen, ino_t ino,
++		       unsigned int d_type, aufs_bindex_t bindex,
++		       unsigned char shwh);
++void au_vdir_free(struct au_vdir *vdir);
++int au_vdir_init(struct file *file);
++int au_vdir_fill_de(struct file *file, struct dir_context *ctx);
++
++/* ioctl.c */
++long aufs_ioctl_dir(struct file *file, unsigned int cmd, unsigned long arg);
++
++#ifdef CONFIG_AUFS_RDU
++/* rdu.c */
++long au_rdu_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
++#ifdef CONFIG_COMPAT
++long au_rdu_compat_ioctl(struct file *file, unsigned int cmd,
++			 unsigned long arg);
++#endif
++#else
++AuStub(long, au_rdu_ioctl, return -EINVAL, struct file *file,
++       unsigned int cmd, unsigned long arg)
++#ifdef CONFIG_COMPAT
++AuStub(long, au_rdu_compat_ioctl, return -EINVAL, struct file *file,
++       unsigned int cmd, unsigned long arg)
++#endif
++#endif
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DIR_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/dynop.c linux-4.0.4/fs/aufs/dynop.c
+--- linux-4.0.4.orig/fs/aufs/dynop.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dynop.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,356 @@
++/*
++ * Copyright (C) 2010-2015 Junjiro R. Okajima
++ */
++
++/*
++ * dynamically customizable operations for regular files
++ */
++
++#include "aufs.h"
++
++#define DyPrSym(key)	AuDbgSym(key->dk_op.dy_hop)
++
++/*
++ * How large will these lists be?
++ * Usually just a few elements, 20-30 at most for each, I guess.
++ */
++static struct au_splhead dynop[AuDyLast];
++
++static struct au_dykey *dy_gfind_get(struct au_splhead *spl, const void *h_op)
++{
++	struct au_dykey *key, *tmp;
++	struct list_head *head;
++
++	key = NULL;
++	head = &spl->head;
++	rcu_read_lock();
++	list_for_each_entry_rcu(tmp, head, dk_list)
++		if (tmp->dk_op.dy_hop == h_op) {
++			key = tmp;
++			kref_get(&key->dk_kref);
++			break;
++		}
++	rcu_read_unlock();
++
++	return key;
++}
++
++static struct au_dykey *dy_bradd(struct au_branch *br, struct au_dykey *key)
++{
++	struct au_dykey **k, *found;
++	const void *h_op = key->dk_op.dy_hop;
++	int i;
++
++	found = NULL;
++	k = br->br_dykey;
++	for (i = 0; i < AuBrDynOp; i++)
++		if (k[i]) {
++			if (k[i]->dk_op.dy_hop == h_op) {
++				found = k[i];
++				break;
++			}
++		} else
++			break;
++	if (!found) {
++		spin_lock(&br->br_dykey_lock);
++		for (; i < AuBrDynOp; i++)
++			if (k[i]) {
++				if (k[i]->dk_op.dy_hop == h_op) {
++					found = k[i];
++					break;
++				}
++			} else {
++				k[i] = key;
++				break;
++			}
++		spin_unlock(&br->br_dykey_lock);
++		BUG_ON(i == AuBrDynOp); /* expand the array */
++	}
++
++	return found;
++}
++
++/* kref_get() if @key is already added */
++static struct au_dykey *dy_gadd(struct au_splhead *spl, struct au_dykey *key)
++{
++	struct au_dykey *tmp, *found;
++	struct list_head *head;
++	const void *h_op = key->dk_op.dy_hop;
++
++	found = NULL;
++	head = &spl->head;
++	spin_lock(&spl->spin);
++	list_for_each_entry(tmp, head, dk_list)
++		if (tmp->dk_op.dy_hop == h_op) {
++			kref_get(&tmp->dk_kref);
++			found = tmp;
++			break;
++		}
++	if (!found)
++		list_add_rcu(&key->dk_list, head);
++	spin_unlock(&spl->spin);
++
++	if (!found)
++		DyPrSym(key);
++	return found;
++}
++
++static void dy_free_rcu(struct rcu_head *rcu)
++{
++	struct au_dykey *key;
++
++	key = container_of(rcu, struct au_dykey, dk_rcu);
++	DyPrSym(key);
++	kfree(key);
++}
++
++static void dy_free(struct kref *kref)
++{
++	struct au_dykey *key;
++	struct au_splhead *spl;
++
++	key = container_of(kref, struct au_dykey, dk_kref);
++	spl = dynop + key->dk_op.dy_type;
++	au_spl_del_rcu(&key->dk_list, spl);
++	call_rcu(&key->dk_rcu, dy_free_rcu);
++}
++
++void au_dy_put(struct au_dykey *key)
++{
++	kref_put(&key->dk_kref, dy_free);
++}
++
++/* ---------------------------------------------------------------------- */
++
++#define DyDbgSize(cnt, op)	AuDebugOn(cnt != sizeof(op)/sizeof(void *))
++
++#ifdef CONFIG_AUFS_DEBUG
++#define DyDbgDeclare(cnt)	unsigned int cnt = 0
++#define DyDbgInc(cnt)		do { cnt++; } while (0)
++#else
++#define DyDbgDeclare(cnt)	do {} while (0)
++#define DyDbgInc(cnt)		do {} while (0)
++#endif
++
++#define DySet(func, dst, src, h_op, h_sb) do {				\
++	DyDbgInc(cnt);							\
++	if (h_op->func) {						\
++		if (src.func)						\
++			dst.func = src.func;				\
++		else							\
++			AuDbg("%s %s\n", au_sbtype(h_sb), #func);	\
++	}								\
++} while (0)
++
++#define DySetForce(func, dst, src) do {		\
++	AuDebugOn(!src.func);			\
++	DyDbgInc(cnt);				\
++	dst.func = src.func;			\
++} while (0)
++
++#define DySetAop(func) \
++	DySet(func, dyaop->da_op, aufs_aop, h_aop, h_sb)
++#define DySetAopForce(func) \
++	DySetForce(func, dyaop->da_op, aufs_aop)
++
++static void dy_aop(struct au_dykey *key, const void *h_op,
++		   struct super_block *h_sb __maybe_unused)
++{
++	struct au_dyaop *dyaop = (void *)key;
++	const struct address_space_operations *h_aop = h_op;
++	DyDbgDeclare(cnt);
++
++	AuDbg("%s\n", au_sbtype(h_sb));
++
++	DySetAop(writepage);
++	DySetAopForce(readpage);	/* force */
++	DySetAop(writepages);
++	DySetAop(set_page_dirty);
++	DySetAop(readpages);
++	DySetAop(write_begin);
++	DySetAop(write_end);
++	DySetAop(bmap);
++	DySetAop(invalidatepage);
++	DySetAop(releasepage);
++	DySetAop(freepage);
++	/* this one will be changed according to an aufs mount option */
++	DySetAop(direct_IO);
++	DySetAop(migratepage);
++	DySetAop(launder_page);
++	DySetAop(is_partially_uptodate);
++	DySetAop(is_dirty_writeback);
++	DySetAop(error_remove_page);
++	DySetAop(swap_activate);
++	DySetAop(swap_deactivate);
++
++	DyDbgSize(cnt, *h_aop);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void dy_bug(struct kref *kref)
++{
++	BUG();
++}
++
++static struct au_dykey *dy_get(struct au_dynop *op, struct au_branch *br)
++{
++	struct au_dykey *key, *old;
++	struct au_splhead *spl;
++	struct op {
++		unsigned int sz;
++		void (*set)(struct au_dykey *key, const void *h_op,
++			    struct super_block *h_sb __maybe_unused);
++	};
++	static const struct op a[] = {
++		[AuDy_AOP] = {
++			.sz	= sizeof(struct au_dyaop),
++			.set	= dy_aop
++		}
++	};
++	const struct op *p;
++
++	spl = dynop + op->dy_type;
++	key = dy_gfind_get(spl, op->dy_hop);
++	if (key)
++		goto out_add; /* success */
++
++	p = a + op->dy_type;
++	key = kzalloc(p->sz, GFP_NOFS);
++	if (unlikely(!key)) {
++		key = ERR_PTR(-ENOMEM);
++		goto out;
++	}
++
++	key->dk_op.dy_hop = op->dy_hop;
++	kref_init(&key->dk_kref);
++	p->set(key, op->dy_hop, au_br_sb(br));
++	old = dy_gadd(spl, key);
++	if (old) {
++		kfree(key);
++		key = old;
++	}
++
++out_add:
++	old = dy_bradd(br, key);
++	if (old)
++		/* its ref-count should never be zero here */
++		kref_put(&key->dk_kref, dy_bug);
++out:
++	return key;
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * Aufs prohibits O_DIRECT by defaut even if the branch supports it.
++ * This behaviour is necessary to return an error from open(O_DIRECT) instead
++ * of the succeeding I/O. The dio mount option enables O_DIRECT and makes
++ * open(O_DIRECT) always succeed, but the succeeding I/O may return an error.
++ * See the aufs manual in detail.
++ */
++static void dy_adx(struct au_dyaop *dyaop, int do_dx)
++{
++	if (!do_dx)
++		dyaop->da_op.direct_IO = NULL;
++	else
++		dyaop->da_op.direct_IO = aufs_aop.direct_IO;
++}
++
++static struct au_dyaop *dy_aget(struct au_branch *br,
++				const struct address_space_operations *h_aop,
++				int do_dx)
++{
++	struct au_dyaop *dyaop;
++	struct au_dynop op;
++
++	op.dy_type = AuDy_AOP;
++	op.dy_haop = h_aop;
++	dyaop = (void *)dy_get(&op, br);
++	if (IS_ERR(dyaop))
++		goto out;
++	dy_adx(dyaop, do_dx);
++
++out:
++	return dyaop;
++}
++
++int au_dy_iaop(struct inode *inode, aufs_bindex_t bindex,
++		struct inode *h_inode)
++{
++	int err, do_dx;
++	struct super_block *sb;
++	struct au_branch *br;
++	struct au_dyaop *dyaop;
++
++	AuDebugOn(!S_ISREG(h_inode->i_mode));
++	IiMustWriteLock(inode);
++
++	sb = inode->i_sb;
++	br = au_sbr(sb, bindex);
++	do_dx = !!au_opt_test(au_mntflags(sb), DIO);
++	dyaop = dy_aget(br, h_inode->i_mapping->a_ops, do_dx);
++	err = PTR_ERR(dyaop);
++	if (IS_ERR(dyaop))
++		/* unnecessary to call dy_fput() */
++		goto out;
++
++	err = 0;
++	inode->i_mapping->a_ops = &dyaop->da_op;
++
++out:
++	return err;
++}
++
++/*
++ * Is it safe to replace a_ops during the inode/file is in operation?
++ * Yes, I hope so.
++ */
++int au_dy_irefresh(struct inode *inode)
++{
++	int err;
++	aufs_bindex_t bstart;
++	struct inode *h_inode;
++
++	err = 0;
++	if (S_ISREG(inode->i_mode)) {
++		bstart = au_ibstart(inode);
++		h_inode = au_h_iptr(inode, bstart);
++		err = au_dy_iaop(inode, bstart, h_inode);
++	}
++	return err;
++}
++
++void au_dy_arefresh(int do_dx)
++{
++	struct au_splhead *spl;
++	struct list_head *head;
++	struct au_dykey *key;
++
++	spl = dynop + AuDy_AOP;
++	head = &spl->head;
++	spin_lock(&spl->spin);
++	list_for_each_entry(key, head, dk_list)
++		dy_adx((void *)key, do_dx);
++	spin_unlock(&spl->spin);
++}
++
++/* ---------------------------------------------------------------------- */
++
++void __init au_dy_init(void)
++{
++	int i;
++
++	/* make sure that 'struct au_dykey *' can be any type */
++	BUILD_BUG_ON(offsetof(struct au_dyaop, da_key));
++
++	for (i = 0; i < AuDyLast; i++)
++		au_spl_init(dynop + i);
++}
++
++void au_dy_fin(void)
++{
++	int i;
++
++	for (i = 0; i < AuDyLast; i++)
++		WARN_ON(!list_empty(&dynop[i].head));
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/dynop.h linux-4.0.4/fs/aufs/dynop.h
+--- linux-4.0.4.orig/fs/aufs/dynop.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/dynop.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,61 @@
++/*
++ * Copyright (C) 2010-2015 Junjiro R. Okajima
++ */
++
++/*
++ * dynamically customizable operations (for regular files only)
++ */
++
++#ifndef __AUFS_DYNOP_H__
++#define __AUFS_DYNOP_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/kref.h>
++
++enum {AuDy_AOP, AuDyLast};
++
++struct au_dynop {
++	int						dy_type;
++	union {
++		const void				*dy_hop;
++		const struct address_space_operations	*dy_haop;
++	};
++};
++
++struct au_dykey {
++	union {
++		struct list_head	dk_list;
++		struct rcu_head		dk_rcu;
++	};
++	struct au_dynop		dk_op;
++
++	/*
++	 * during I am in the branch local array, kref is gotten. when the
++	 * branch is removed, kref is put.
++	 */
++	struct kref		dk_kref;
++};
++
++/* stop unioning since their sizes are very different from each other */
++struct au_dyaop {
++	struct au_dykey			da_key;
++	struct address_space_operations	da_op; /* not const */
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* dynop.c */
++struct au_branch;
++void au_dy_put(struct au_dykey *key);
++int au_dy_iaop(struct inode *inode, aufs_bindex_t bindex,
++		struct inode *h_inode);
++int au_dy_irefresh(struct inode *inode);
++void au_dy_arefresh(int do_dio);
++
++void __init au_dy_init(void);
++void au_dy_fin(void);
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_DYNOP_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/export.c linux-4.0.4/fs/aufs/export.c
+--- linux-4.0.4.orig/fs/aufs/export.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/export.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,818 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * export via nfs
++ */
++
++#include <linux/exportfs.h>
++#include <linux/fs_struct.h>
++#include <linux/namei.h>
++#include <linux/nsproxy.h>
++#include <linux/random.h>
++#include <linux/writeback.h>
++#include "../fs/mount.h"
++#include "aufs.h"
++
++union conv {
++#ifdef CONFIG_AUFS_INO_T_64
++	__u32 a[2];
++#else
++	__u32 a[1];
++#endif
++	ino_t ino;
++};
++
++static ino_t decode_ino(__u32 *a)
++{
++	union conv u;
++
++	BUILD_BUG_ON(sizeof(u.ino) != sizeof(u.a));
++	u.a[0] = a[0];
++#ifdef CONFIG_AUFS_INO_T_64
++	u.a[1] = a[1];
++#endif
++	return u.ino;
++}
++
++static void encode_ino(__u32 *a, ino_t ino)
++{
++	union conv u;
++
++	u.ino = ino;
++	a[0] = u.a[0];
++#ifdef CONFIG_AUFS_INO_T_64
++	a[1] = u.a[1];
++#endif
++}
++
++/* NFS file handle */
++enum {
++	Fh_br_id,
++	Fh_sigen,
++#ifdef CONFIG_AUFS_INO_T_64
++	/* support 64bit inode number */
++	Fh_ino1,
++	Fh_ino2,
++	Fh_dir_ino1,
++	Fh_dir_ino2,
++#else
++	Fh_ino1,
++	Fh_dir_ino1,
++#endif
++	Fh_igen,
++	Fh_h_type,
++	Fh_tail,
++
++	Fh_ino = Fh_ino1,
++	Fh_dir_ino = Fh_dir_ino1
++};
++
++static int au_test_anon(struct dentry *dentry)
++{
++	/* note: read d_flags without d_lock */
++	return !!(dentry->d_flags & DCACHE_DISCONNECTED);
++}
++
++int au_test_nfsd(void)
++{
++	int ret;
++	struct task_struct *tsk = current;
++	char comm[sizeof(tsk->comm)];
++
++	ret = 0;
++	if (tsk->flags & PF_KTHREAD) {
++		get_task_comm(comm, tsk);
++		ret = !strcmp(comm, "nfsd");
++	}
++
++	return ret;
++}
++
++/* ---------------------------------------------------------------------- */
++/* inode generation external table */
++
++void au_xigen_inc(struct inode *inode)
++{
++	loff_t pos;
++	ssize_t sz;
++	__u32 igen;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++
++	sb = inode->i_sb;
++	AuDebugOn(!au_opt_test(au_mntflags(sb), XINO));
++
++	sbinfo = au_sbi(sb);
++	pos = inode->i_ino;
++	pos *= sizeof(igen);
++	igen = inode->i_generation + 1;
++	sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xigen, &igen,
++			 sizeof(igen), &pos);
++	if (sz == sizeof(igen))
++		return; /* success */
++
++	if (unlikely(sz >= 0))
++		AuIOErr("xigen error (%zd)\n", sz);
++}
++
++int au_xigen_new(struct inode *inode)
++{
++	int err;
++	loff_t pos;
++	ssize_t sz;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++	struct file *file;
++
++	err = 0;
++	/* todo: dirty, at mount time */
++	if (inode->i_ino == AUFS_ROOT_INO)
++		goto out;
++	sb = inode->i_sb;
++	SiMustAnyLock(sb);
++	if (unlikely(!au_opt_test(au_mntflags(sb), XINO)))
++		goto out;
++
++	err = -EFBIG;
++	pos = inode->i_ino;
++	if (unlikely(au_loff_max / sizeof(inode->i_generation) - 1 < pos)) {
++		AuIOErr1("too large i%lld\n", pos);
++		goto out;
++	}
++	pos *= sizeof(inode->i_generation);
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	file = sbinfo->si_xigen;
++	BUG_ON(!file);
++
++	if (vfsub_f_size_read(file)
++	    < pos + sizeof(inode->i_generation)) {
++		inode->i_generation = atomic_inc_return(&sbinfo->si_xigen_next);
++		sz = xino_fwrite(sbinfo->si_xwrite, file, &inode->i_generation,
++				 sizeof(inode->i_generation), &pos);
++	} else
++		sz = xino_fread(sbinfo->si_xread, file, &inode->i_generation,
++				sizeof(inode->i_generation), &pos);
++	if (sz == sizeof(inode->i_generation))
++		goto out; /* success */
++
++	err = sz;
++	if (unlikely(sz >= 0)) {
++		err = -EIO;
++		AuIOErr("xigen error (%zd)\n", sz);
++	}
++
++out:
++	return err;
++}
++
++int au_xigen_set(struct super_block *sb, struct file *base)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++	struct file *file;
++
++	SiMustWriteLock(sb);
++
++	sbinfo = au_sbi(sb);
++	file = au_xino_create2(base, sbinfo->si_xigen);
++	err = PTR_ERR(file);
++	if (IS_ERR(file))
++		goto out;
++	err = 0;
++	if (sbinfo->si_xigen)
++		fput(sbinfo->si_xigen);
++	sbinfo->si_xigen = file;
++
++out:
++	return err;
++}
++
++void au_xigen_clr(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	SiMustWriteLock(sb);
++
++	sbinfo = au_sbi(sb);
++	if (sbinfo->si_xigen) {
++		fput(sbinfo->si_xigen);
++		sbinfo->si_xigen = NULL;
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct dentry *decode_by_ino(struct super_block *sb, ino_t ino,
++				    ino_t dir_ino)
++{
++	struct dentry *dentry, *d;
++	struct inode *inode;
++	unsigned int sigen;
++
++	dentry = NULL;
++	inode = ilookup(sb, ino);
++	if (!inode)
++		goto out;
++
++	dentry = ERR_PTR(-ESTALE);
++	sigen = au_sigen(sb);
++	if (unlikely(is_bad_inode(inode)
++		     || IS_DEADDIR(inode)
++		     || sigen != au_iigen(inode, NULL)))
++		goto out_iput;
++
++	dentry = NULL;
++	if (!dir_ino || S_ISDIR(inode->i_mode))
++		dentry = d_find_alias(inode);
++	else {
++		spin_lock(&inode->i_lock);
++		hlist_for_each_entry(d, &inode->i_dentry, d_u.d_alias) {
++			spin_lock(&d->d_lock);
++			if (!au_test_anon(d)
++			    && d->d_parent->d_inode->i_ino == dir_ino) {
++				dentry = dget_dlock(d);
++				spin_unlock(&d->d_lock);
++				break;
++			}
++			spin_unlock(&d->d_lock);
++		}
++		spin_unlock(&inode->i_lock);
++	}
++	if (unlikely(dentry && au_digen_test(dentry, sigen))) {
++		/* need to refresh */
++		dput(dentry);
++		dentry = NULL;
++	}
++
++out_iput:
++	iput(inode);
++out:
++	AuTraceErrPtr(dentry);
++	return dentry;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* todo: dirty? */
++/* if exportfs_decode_fh() passed vfsmount*, we could be happy */
++
++struct au_compare_mnt_args {
++	/* input */
++	struct super_block *sb;
++
++	/* output */
++	struct vfsmount *mnt;
++};
++
++static int au_compare_mnt(struct vfsmount *mnt, void *arg)
++{
++	struct au_compare_mnt_args *a = arg;
++
++	if (mnt->mnt_sb != a->sb)
++		return 0;
++	a->mnt = mntget(mnt);
++	return 1;
++}
++
++static struct vfsmount *au_mnt_get(struct super_block *sb)
++{
++	int err;
++	struct path root;
++	struct au_compare_mnt_args args = {
++		.sb = sb
++	};
++
++	get_fs_root(current->fs, &root);
++	rcu_read_lock();
++	err = iterate_mounts(au_compare_mnt, &args, root.mnt);
++	rcu_read_unlock();
++	path_put(&root);
++	AuDebugOn(!err);
++	AuDebugOn(!args.mnt);
++	return args.mnt;
++}
++
++struct au_nfsd_si_lock {
++	unsigned int sigen;
++	aufs_bindex_t bindex, br_id;
++	unsigned char force_lock;
++};
++
++static int si_nfsd_read_lock(struct super_block *sb,
++			     struct au_nfsd_si_lock *nsi_lock)
++{
++	int err;
++	aufs_bindex_t bindex;
++
++	si_read_lock(sb, AuLock_FLUSH);
++
++	/* branch id may be wrapped around */
++	err = 0;
++	bindex = au_br_index(sb, nsi_lock->br_id);
++	if (bindex >= 0 && nsi_lock->sigen + AUFS_BRANCH_MAX > au_sigen(sb))
++		goto out; /* success */
++
++	err = -ESTALE;
++	bindex = -1;
++	if (!nsi_lock->force_lock)
++		si_read_unlock(sb);
++
++out:
++	nsi_lock->bindex = bindex;
++	return err;
++}
++
++struct find_name_by_ino {
++	struct dir_context ctx;
++	int called, found;
++	ino_t ino;
++	char *name;
++	int namelen;
++};
++
++static int
++find_name_by_ino(struct dir_context *ctx, const char *name, int namelen,
++		 loff_t offset, u64 ino, unsigned int d_type)
++{
++	struct find_name_by_ino *a = container_of(ctx, struct find_name_by_ino,
++						  ctx);
++
++	a->called++;
++	if (a->ino != ino)
++		return 0;
++
++	memcpy(a->name, name, namelen);
++	a->namelen = namelen;
++	a->found = 1;
++	return 1;
++}
++
++static struct dentry *au_lkup_by_ino(struct path *path, ino_t ino,
++				     struct au_nfsd_si_lock *nsi_lock)
++{
++	struct dentry *dentry, *parent;
++	struct file *file;
++	struct inode *dir;
++	struct find_name_by_ino arg = {
++		.ctx = {
++			.actor = find_name_by_ino
++		}
++	};
++	int err;
++
++	parent = path->dentry;
++	if (nsi_lock)
++		si_read_unlock(parent->d_sb);
++	file = vfsub_dentry_open(path, au_dir_roflags);
++	dentry = (void *)file;
++	if (IS_ERR(file))
++		goto out;
++
++	dentry = ERR_PTR(-ENOMEM);
++	arg.name = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!arg.name))
++		goto out_file;
++	arg.ino = ino;
++	arg.found = 0;
++	do {
++		arg.called = 0;
++		/* smp_mb(); */
++		err = vfsub_iterate_dir(file, &arg.ctx);
++	} while (!err && !arg.found && arg.called);
++	dentry = ERR_PTR(err);
++	if (unlikely(err))
++		goto out_name;
++	/* instead of ENOENT */
++	dentry = ERR_PTR(-ESTALE);
++	if (!arg.found)
++		goto out_name;
++
++	/* do not call vfsub_lkup_one() */
++	dir = parent->d_inode;
++	mutex_lock(&dir->i_mutex);
++	dentry = vfsub_lookup_one_len(arg.name, parent, arg.namelen);
++	mutex_unlock(&dir->i_mutex);
++	AuTraceErrPtr(dentry);
++	if (IS_ERR(dentry))
++		goto out_name;
++	AuDebugOn(au_test_anon(dentry));
++	if (unlikely(!dentry->d_inode)) {
++		dput(dentry);
++		dentry = ERR_PTR(-ENOENT);
++	}
++
++out_name:
++	free_page((unsigned long)arg.name);
++out_file:
++	fput(file);
++out:
++	if (unlikely(nsi_lock
++		     && si_nfsd_read_lock(parent->d_sb, nsi_lock) < 0))
++		if (!IS_ERR(dentry)) {
++			dput(dentry);
++			dentry = ERR_PTR(-ESTALE);
++		}
++	AuTraceErrPtr(dentry);
++	return dentry;
++}
++
++static struct dentry *decode_by_dir_ino(struct super_block *sb, ino_t ino,
++					ino_t dir_ino,
++					struct au_nfsd_si_lock *nsi_lock)
++{
++	struct dentry *dentry;
++	struct path path;
++
++	if (dir_ino != AUFS_ROOT_INO) {
++		path.dentry = decode_by_ino(sb, dir_ino, 0);
++		dentry = path.dentry;
++		if (!path.dentry || IS_ERR(path.dentry))
++			goto out;
++		AuDebugOn(au_test_anon(path.dentry));
++	} else
++		path.dentry = dget(sb->s_root);
++
++	path.mnt = au_mnt_get(sb);
++	dentry = au_lkup_by_ino(&path, ino, nsi_lock);
++	path_put(&path);
++
++out:
++	AuTraceErrPtr(dentry);
++	return dentry;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int h_acceptable(void *expv, struct dentry *dentry)
++{
++	return 1;
++}
++
++static char *au_build_path(struct dentry *h_parent, struct path *h_rootpath,
++			   char *buf, int len, struct super_block *sb)
++{
++	char *p;
++	int n;
++	struct path path;
++
++	p = d_path(h_rootpath, buf, len);
++	if (IS_ERR(p))
++		goto out;
++	n = strlen(p);
++
++	path.mnt = h_rootpath->mnt;
++	path.dentry = h_parent;
++	p = d_path(&path, buf, len);
++	if (IS_ERR(p))
++		goto out;
++	if (n != 1)
++		p += n;
++
++	path.mnt = au_mnt_get(sb);
++	path.dentry = sb->s_root;
++	p = d_path(&path, buf, len - strlen(p));
++	mntput(path.mnt);
++	if (IS_ERR(p))
++		goto out;
++	if (n != 1)
++		p[strlen(p)] = '/';
++
++out:
++	AuTraceErrPtr(p);
++	return p;
++}
++
++static
++struct dentry *decode_by_path(struct super_block *sb, ino_t ino, __u32 *fh,
++			      int fh_len, struct au_nfsd_si_lock *nsi_lock)
++{
++	struct dentry *dentry, *h_parent, *root;
++	struct super_block *h_sb;
++	char *pathname, *p;
++	struct vfsmount *h_mnt;
++	struct au_branch *br;
++	int err;
++	struct path path;
++
++	br = au_sbr(sb, nsi_lock->bindex);
++	h_mnt = au_br_mnt(br);
++	h_sb = h_mnt->mnt_sb;
++	/* todo: call lower fh_to_dentry()? fh_to_parent()? */
++	h_parent = exportfs_decode_fh(h_mnt, (void *)(fh + Fh_tail),
++				      fh_len - Fh_tail, fh[Fh_h_type],
++				      h_acceptable, /*context*/NULL);
++	dentry = h_parent;
++	if (unlikely(!h_parent || IS_ERR(h_parent))) {
++		AuWarn1("%s decode_fh failed, %ld\n",
++			au_sbtype(h_sb), PTR_ERR(h_parent));
++		goto out;
++	}
++	dentry = NULL;
++	if (unlikely(au_test_anon(h_parent))) {
++		AuWarn1("%s decode_fh returned a disconnected dentry\n",
++			au_sbtype(h_sb));
++		goto out_h_parent;
++	}
++
++	dentry = ERR_PTR(-ENOMEM);
++	pathname = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!pathname))
++		goto out_h_parent;
++
++	root = sb->s_root;
++	path.mnt = h_mnt;
++	di_read_lock_parent(root, !AuLock_IR);
++	path.dentry = au_h_dptr(root, nsi_lock->bindex);
++	di_read_unlock(root, !AuLock_IR);
++	p = au_build_path(h_parent, &path, pathname, PAGE_SIZE, sb);
++	dentry = (void *)p;
++	if (IS_ERR(p))
++		goto out_pathname;
++
++	si_read_unlock(sb);
++	err = vfsub_kern_path(p, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
++	dentry = ERR_PTR(err);
++	if (unlikely(err))
++		goto out_relock;
++
++	dentry = ERR_PTR(-ENOENT);
++	AuDebugOn(au_test_anon(path.dentry));
++	if (unlikely(!path.dentry->d_inode))
++		goto out_path;
++
++	if (ino != path.dentry->d_inode->i_ino)
++		dentry = au_lkup_by_ino(&path, ino, /*nsi_lock*/NULL);
++	else
++		dentry = dget(path.dentry);
++
++out_path:
++	path_put(&path);
++out_relock:
++	if (unlikely(si_nfsd_read_lock(sb, nsi_lock) < 0))
++		if (!IS_ERR(dentry)) {
++			dput(dentry);
++			dentry = ERR_PTR(-ESTALE);
++		}
++out_pathname:
++	free_page((unsigned long)pathname);
++out_h_parent:
++	dput(h_parent);
++out:
++	AuTraceErrPtr(dentry);
++	return dentry;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct dentry *
++aufs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
++		  int fh_type)
++{
++	struct dentry *dentry;
++	__u32 *fh = fid->raw;
++	struct au_branch *br;
++	ino_t ino, dir_ino;
++	struct au_nfsd_si_lock nsi_lock = {
++		.force_lock	= 0
++	};
++
++	dentry = ERR_PTR(-ESTALE);
++	/* it should never happen, but the file handle is unreliable */
++	if (unlikely(fh_len < Fh_tail))
++		goto out;
++	nsi_lock.sigen = fh[Fh_sigen];
++	nsi_lock.br_id = fh[Fh_br_id];
++
++	/* branch id may be wrapped around */
++	br = NULL;
++	if (unlikely(si_nfsd_read_lock(sb, &nsi_lock)))
++		goto out;
++	nsi_lock.force_lock = 1;
++
++	/* is this inode still cached? */
++	ino = decode_ino(fh + Fh_ino);
++	/* it should never happen */
++	if (unlikely(ino == AUFS_ROOT_INO))
++		goto out;
++
++	dir_ino = decode_ino(fh + Fh_dir_ino);
++	dentry = decode_by_ino(sb, ino, dir_ino);
++	if (IS_ERR(dentry))
++		goto out_unlock;
++	if (dentry)
++		goto accept;
++
++	/* is the parent dir cached? */
++	br = au_sbr(sb, nsi_lock.bindex);
++	atomic_inc(&br->br_count);
++	dentry = decode_by_dir_ino(sb, ino, dir_ino, &nsi_lock);
++	if (IS_ERR(dentry))
++		goto out_unlock;
++	if (dentry)
++		goto accept;
++
++	/* lookup path */
++	dentry = decode_by_path(sb, ino, fh, fh_len, &nsi_lock);
++	if (IS_ERR(dentry))
++		goto out_unlock;
++	if (unlikely(!dentry))
++		/* todo?: make it ESTALE */
++		goto out_unlock;
++
++accept:
++	if (!au_digen_test(dentry, au_sigen(sb))
++	    && dentry->d_inode->i_generation == fh[Fh_igen])
++		goto out_unlock; /* success */
++
++	dput(dentry);
++	dentry = ERR_PTR(-ESTALE);
++out_unlock:
++	if (br)
++		atomic_dec(&br->br_count);
++	si_read_unlock(sb);
++out:
++	AuTraceErrPtr(dentry);
++	return dentry;
++}
++
++#if 0 /* reserved for future use */
++/* support subtreecheck option */
++static struct dentry *aufs_fh_to_parent(struct super_block *sb, struct fid *fid,
++					int fh_len, int fh_type)
++{
++	struct dentry *parent;
++	__u32 *fh = fid->raw;
++	ino_t dir_ino;
++
++	dir_ino = decode_ino(fh + Fh_dir_ino);
++	parent = decode_by_ino(sb, dir_ino, 0);
++	if (IS_ERR(parent))
++		goto out;
++	if (!parent)
++		parent = decode_by_path(sb, au_br_index(sb, fh[Fh_br_id]),
++					dir_ino, fh, fh_len);
++
++out:
++	AuTraceErrPtr(parent);
++	return parent;
++}
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++static int aufs_encode_fh(struct inode *inode, __u32 *fh, int *max_len,
++			  struct inode *dir)
++{
++	int err;
++	aufs_bindex_t bindex;
++	struct super_block *sb, *h_sb;
++	struct dentry *dentry, *parent, *h_parent;
++	struct inode *h_dir;
++	struct au_branch *br;
++
++	err = -ENOSPC;
++	if (unlikely(*max_len <= Fh_tail)) {
++		AuWarn1("NFSv2 client (max_len %d)?\n", *max_len);
++		goto out;
++	}
++
++	err = FILEID_ROOT;
++	if (inode->i_ino == AUFS_ROOT_INO) {
++		AuDebugOn(inode->i_ino != AUFS_ROOT_INO);
++		goto out;
++	}
++
++	h_parent = NULL;
++	sb = inode->i_sb;
++	err = si_read_lock(sb, AuLock_FLUSH);
++	if (unlikely(err))
++		goto out;
++
++#ifdef CONFIG_AUFS_DEBUG
++	if (unlikely(!au_opt_test(au_mntflags(sb), XINO)))
++		AuWarn1("NFS-exporting requires xino\n");
++#endif
++	err = -EIO;
++	parent = NULL;
++	ii_read_lock_child(inode);
++	bindex = au_ibstart(inode);
++	if (!dir) {
++		dentry = d_find_any_alias(inode);
++		if (unlikely(!dentry))
++			goto out_unlock;
++		AuDebugOn(au_test_anon(dentry));
++		parent = dget_parent(dentry);
++		dput(dentry);
++		if (unlikely(!parent))
++			goto out_unlock;
++		dir = parent->d_inode;
++	}
++
++	ii_read_lock_parent(dir);
++	h_dir = au_h_iptr(dir, bindex);
++	ii_read_unlock(dir);
++	if (unlikely(!h_dir))
++		goto out_parent;
++	h_parent = d_find_any_alias(h_dir);
++	if (unlikely(!h_parent))
++		goto out_hparent;
++
++	err = -EPERM;
++	br = au_sbr(sb, bindex);
++	h_sb = au_br_sb(br);
++	if (unlikely(!h_sb->s_export_op)) {
++		AuErr1("%s branch is not exportable\n", au_sbtype(h_sb));
++		goto out_hparent;
++	}
++
++	fh[Fh_br_id] = br->br_id;
++	fh[Fh_sigen] = au_sigen(sb);
++	encode_ino(fh + Fh_ino, inode->i_ino);
++	encode_ino(fh + Fh_dir_ino, dir->i_ino);
++	fh[Fh_igen] = inode->i_generation;
++
++	*max_len -= Fh_tail;
++	fh[Fh_h_type] = exportfs_encode_fh(h_parent, (void *)(fh + Fh_tail),
++					   max_len,
++					   /*connectable or subtreecheck*/0);
++	err = fh[Fh_h_type];
++	*max_len += Fh_tail;
++	/* todo: macros? */
++	if (err != FILEID_INVALID)
++		err = 99;
++	else
++		AuWarn1("%s encode_fh failed\n", au_sbtype(h_sb));
++
++out_hparent:
++	dput(h_parent);
++out_parent:
++	dput(parent);
++out_unlock:
++	ii_read_unlock(inode);
++	si_read_unlock(sb);
++out:
++	if (unlikely(err < 0))
++		err = FILEID_INVALID;
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int aufs_commit_metadata(struct inode *inode)
++{
++	int err;
++	aufs_bindex_t bindex;
++	struct super_block *sb;
++	struct inode *h_inode;
++	int (*f)(struct inode *inode);
++
++	sb = inode->i_sb;
++	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
++	ii_write_lock_child(inode);
++	bindex = au_ibstart(inode);
++	AuDebugOn(bindex < 0);
++	h_inode = au_h_iptr(inode, bindex);
++
++	f = h_inode->i_sb->s_export_op->commit_metadata;
++	if (f)
++		err = f(h_inode);
++	else {
++		struct writeback_control wbc = {
++			.sync_mode	= WB_SYNC_ALL,
++			.nr_to_write	= 0 /* metadata only */
++		};
++
++		err = sync_inode(h_inode, &wbc);
++	}
++
++	au_cpup_attr_timesizes(inode);
++	ii_write_unlock(inode);
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct export_operations aufs_export_op = {
++	.fh_to_dentry		= aufs_fh_to_dentry,
++	/* .fh_to_parent	= aufs_fh_to_parent, */
++	.encode_fh		= aufs_encode_fh,
++	.commit_metadata	= aufs_commit_metadata
++};
++
++void au_export_init(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++	__u32 u;
++
++	sb->s_export_op = &aufs_export_op;
++	sbinfo = au_sbi(sb);
++	sbinfo->si_xigen = NULL;
++	get_random_bytes(&u, sizeof(u));
++	BUILD_BUG_ON(sizeof(u) != sizeof(int));
++	atomic_set(&sbinfo->si_xigen_next, u);
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/fhsm.c linux-4.0.4/fs/aufs/fhsm.c
+--- linux-4.0.4.orig/fs/aufs/fhsm.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/fhsm.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,412 @@
++/*
++ * Copyright (C) 2011-2015 Junjiro R. Okajima
++ */
++
++/*
++ * File-based Hierarchy Storage Management
++ */
++
++#include <linux/anon_inodes.h>
++#include <linux/poll.h>
++#include <linux/seq_file.h>
++#include <linux/statfs.h>
++#include "aufs.h"
++
++static aufs_bindex_t au_fhsm_bottom(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++
++	SiMustAnyLock(sb);
++
++	sbinfo = au_sbi(sb);
++	fhsm = &sbinfo->si_fhsm;
++	AuDebugOn(!fhsm);
++	return fhsm->fhsm_bottom;
++}
++
++void au_fhsm_set_bottom(struct super_block *sb, aufs_bindex_t bindex)
++{
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++
++	SiMustWriteLock(sb);
++
++	sbinfo = au_sbi(sb);
++	fhsm = &sbinfo->si_fhsm;
++	AuDebugOn(!fhsm);
++	fhsm->fhsm_bottom = bindex;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_fhsm_test_jiffy(struct au_sbinfo *sbinfo, struct au_branch *br)
++{
++	struct au_br_fhsm *bf;
++
++	bf = br->br_fhsm;
++	MtxMustLock(&bf->bf_lock);
++
++	return !bf->bf_readable
++		|| time_after(jiffies,
++			      bf->bf_jiffy + sbinfo->si_fhsm.fhsm_expire);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void au_fhsm_notify(struct super_block *sb, int val)
++{
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++
++	SiMustAnyLock(sb);
++
++	sbinfo = au_sbi(sb);
++	fhsm = &sbinfo->si_fhsm;
++	if (au_fhsm_pid(fhsm)
++	    && atomic_read(&fhsm->fhsm_readable) != -1) {
++		atomic_set(&fhsm->fhsm_readable, val);
++		if (val)
++			wake_up(&fhsm->fhsm_wqh);
++	}
++}
++
++static int au_fhsm_stfs(struct super_block *sb, aufs_bindex_t bindex,
++			struct aufs_stfs *rstfs, int do_lock, int do_notify)
++{
++	int err;
++	struct au_branch *br;
++	struct au_br_fhsm *bf;
++
++	br = au_sbr(sb, bindex);
++	AuDebugOn(au_br_rdonly(br));
++	bf = br->br_fhsm;
++	AuDebugOn(!bf);
++
++	if (do_lock)
++		mutex_lock(&bf->bf_lock);
++	else
++		MtxMustLock(&bf->bf_lock);
++
++	/* sb->s_root for NFS is unreliable */
++	err = au_br_stfs(br, &bf->bf_stfs);
++	if (unlikely(err)) {
++		AuErr1("FHSM failed (%d), b%d, ignored.\n", bindex, err);
++		goto out;
++	}
++
++	bf->bf_jiffy = jiffies;
++	bf->bf_readable = 1;
++	if (do_notify)
++		au_fhsm_notify(sb, /*val*/1);
++	if (rstfs)
++		*rstfs = bf->bf_stfs;
++
++out:
++	if (do_lock)
++		mutex_unlock(&bf->bf_lock);
++	au_fhsm_notify(sb, /*val*/1);
++
++	return err;
++}
++
++void au_fhsm_wrote(struct super_block *sb, aufs_bindex_t bindex, int force)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++	struct au_branch *br;
++	struct au_br_fhsm *bf;
++
++	AuDbg("b%d, force %d\n", bindex, force);
++	SiMustAnyLock(sb);
++
++	sbinfo = au_sbi(sb);
++	fhsm = &sbinfo->si_fhsm;
++	if (!au_ftest_si(sbinfo, FHSM)
++	    || fhsm->fhsm_bottom == bindex)
++		return;
++
++	br = au_sbr(sb, bindex);
++	bf = br->br_fhsm;
++	AuDebugOn(!bf);
++	mutex_lock(&bf->bf_lock);
++	if (force
++	    || au_fhsm_pid(fhsm)
++	    || au_fhsm_test_jiffy(sbinfo, br))
++		err = au_fhsm_stfs(sb, bindex, /*rstfs*/NULL, /*do_lock*/0,
++				  /*do_notify*/1);
++	mutex_unlock(&bf->bf_lock);
++}
++
++void au_fhsm_wrote_all(struct super_block *sb, int force)
++{
++	aufs_bindex_t bindex, bend;
++	struct au_branch *br;
++
++	/* exclude the bottom */
++	bend = au_fhsm_bottom(sb);
++	for (bindex = 0; bindex < bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		if (au_br_fhsm(br->br_perm))
++			au_fhsm_wrote(sb, bindex, force);
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++static unsigned int au_fhsm_poll(struct file *file,
++				 struct poll_table_struct *wait)
++{
++	unsigned int mask;
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++
++	mask = 0;
++	sbinfo = file->private_data;
++	fhsm = &sbinfo->si_fhsm;
++	poll_wait(file, &fhsm->fhsm_wqh, wait);
++	if (atomic_read(&fhsm->fhsm_readable))
++		mask = POLLIN /* | POLLRDNORM */;
++
++	AuTraceErr((int)mask);
++	return mask;
++}
++
++static int au_fhsm_do_read_one(struct aufs_stbr __user *stbr,
++			      struct aufs_stfs *stfs, __s16 brid)
++{
++	int err;
++
++	err = copy_to_user(&stbr->stfs, stfs, sizeof(*stfs));
++	if (!err)
++		err = __put_user(brid, &stbr->brid);
++	if (unlikely(err))
++		err = -EFAULT;
++
++	return err;
++}
++
++static ssize_t au_fhsm_do_read(struct super_block *sb,
++			       struct aufs_stbr __user *stbr, size_t count)
++{
++	ssize_t err;
++	int nstbr;
++	aufs_bindex_t bindex, bend;
++	struct au_branch *br;
++	struct au_br_fhsm *bf;
++
++	/* except the bottom branch */
++	err = 0;
++	nstbr = 0;
++	bend = au_fhsm_bottom(sb);
++	for (bindex = 0; !err && bindex < bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		if (!au_br_fhsm(br->br_perm))
++			continue;
++
++		bf = br->br_fhsm;
++		mutex_lock(&bf->bf_lock);
++		if (bf->bf_readable) {
++			err = -EFAULT;
++			if (count >= sizeof(*stbr))
++				err = au_fhsm_do_read_one(stbr++, &bf->bf_stfs,
++							  br->br_id);
++			if (!err) {
++				bf->bf_readable = 0;
++				count -= sizeof(*stbr);
++				nstbr++;
++			}
++		}
++		mutex_unlock(&bf->bf_lock);
++	}
++	if (!err)
++		err = sizeof(*stbr) * nstbr;
++
++	return err;
++}
++
++static ssize_t au_fhsm_read(struct file *file, char __user *buf, size_t count,
++			   loff_t *pos)
++{
++	ssize_t err;
++	int readable;
++	aufs_bindex_t nfhsm, bindex, bend;
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++	struct au_branch *br;
++	struct super_block *sb;
++
++	err = 0;
++	sbinfo = file->private_data;
++	fhsm = &sbinfo->si_fhsm;
++need_data:
++	spin_lock_irq(&fhsm->fhsm_wqh.lock);
++	if (!atomic_read(&fhsm->fhsm_readable)) {
++		if (vfsub_file_flags(file) & O_NONBLOCK)
++			err = -EAGAIN;
++		else
++			err = wait_event_interruptible_locked_irq
++				(fhsm->fhsm_wqh,
++				 atomic_read(&fhsm->fhsm_readable));
++	}
++	spin_unlock_irq(&fhsm->fhsm_wqh.lock);
++	if (unlikely(err))
++		goto out;
++
++	/* sb may already be dead */
++	au_rw_read_lock(&sbinfo->si_rwsem);
++	readable = atomic_read(&fhsm->fhsm_readable);
++	if (readable > 0) {
++		sb = sbinfo->si_sb;
++		AuDebugOn(!sb);
++		/* exclude the bottom branch */
++		nfhsm = 0;
++		bend = au_fhsm_bottom(sb);
++		for (bindex = 0; bindex < bend; bindex++) {
++			br = au_sbr(sb, bindex);
++			if (au_br_fhsm(br->br_perm))
++				nfhsm++;
++		}
++		err = -EMSGSIZE;
++		if (nfhsm * sizeof(struct aufs_stbr) <= count) {
++			atomic_set(&fhsm->fhsm_readable, 0);
++			err = au_fhsm_do_read(sbinfo->si_sb, (void __user *)buf,
++					     count);
++		}
++	}
++	au_rw_read_unlock(&sbinfo->si_rwsem);
++	if (!readable)
++		goto need_data;
++
++out:
++	return err;
++}
++
++static int au_fhsm_release(struct inode *inode, struct file *file)
++{
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++
++	/* sb may already be dead */
++	sbinfo = file->private_data;
++	fhsm = &sbinfo->si_fhsm;
++	spin_lock(&fhsm->fhsm_spin);
++	fhsm->fhsm_pid = 0;
++	spin_unlock(&fhsm->fhsm_spin);
++	kobject_put(&sbinfo->si_kobj);
++
++	return 0;
++}
++
++static const struct file_operations au_fhsm_fops = {
++	.owner		= THIS_MODULE,
++	.llseek		= noop_llseek,
++	.read		= au_fhsm_read,
++	.poll		= au_fhsm_poll,
++	.release	= au_fhsm_release
++};
++
++int au_fhsm_fd(struct super_block *sb, int oflags)
++{
++	int err, fd;
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++
++	err = -EPERM;
++	if (unlikely(!capable(CAP_SYS_ADMIN)))
++		goto out;
++
++	err = -EINVAL;
++	if (unlikely(oflags & ~(O_CLOEXEC | O_NONBLOCK)))
++		goto out;
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	fhsm = &sbinfo->si_fhsm;
++	spin_lock(&fhsm->fhsm_spin);
++	if (!fhsm->fhsm_pid)
++		fhsm->fhsm_pid = current->pid;
++	else
++		err = -EBUSY;
++	spin_unlock(&fhsm->fhsm_spin);
++	if (unlikely(err))
++		goto out;
++
++	oflags |= O_RDONLY;
++	/* oflags |= FMODE_NONOTIFY; */
++	fd = anon_inode_getfd("[aufs_fhsm]", &au_fhsm_fops, sbinfo, oflags);
++	err = fd;
++	if (unlikely(fd < 0))
++		goto out_pid;
++
++	/* succeed reglardless 'fhsm' status */
++	kobject_get(&sbinfo->si_kobj);
++	si_noflush_read_lock(sb);
++	if (au_ftest_si(sbinfo, FHSM))
++		au_fhsm_wrote_all(sb, /*force*/0);
++	si_read_unlock(sb);
++	goto out; /* success */
++
++out_pid:
++	spin_lock(&fhsm->fhsm_spin);
++	fhsm->fhsm_pid = 0;
++	spin_unlock(&fhsm->fhsm_spin);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_fhsm_br_alloc(struct au_branch *br)
++{
++	int err;
++
++	err = 0;
++	br->br_fhsm = kmalloc(sizeof(*br->br_fhsm), GFP_NOFS);
++	if (br->br_fhsm)
++		au_br_fhsm_init(br->br_fhsm);
++	else
++		err = -ENOMEM;
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_fhsm_fin(struct super_block *sb)
++{
++	au_fhsm_notify(sb, /*val*/-1);
++}
++
++void au_fhsm_init(struct au_sbinfo *sbinfo)
++{
++	struct au_fhsm *fhsm;
++
++	fhsm = &sbinfo->si_fhsm;
++	spin_lock_init(&fhsm->fhsm_spin);
++	init_waitqueue_head(&fhsm->fhsm_wqh);
++	atomic_set(&fhsm->fhsm_readable, 0);
++	fhsm->fhsm_expire
++		= msecs_to_jiffies(AUFS_FHSM_CACHE_DEF_SEC * MSEC_PER_SEC);
++	fhsm->fhsm_bottom = -1;
++}
++
++void au_fhsm_set(struct au_sbinfo *sbinfo, unsigned int sec)
++{
++	sbinfo->si_fhsm.fhsm_expire
++		= msecs_to_jiffies(sec * MSEC_PER_SEC);
++}
++
++void au_fhsm_show(struct seq_file *seq, struct au_sbinfo *sbinfo)
++{
++	unsigned int u;
++
++	if (!au_ftest_si(sbinfo, FHSM))
++		return;
++
++	u = jiffies_to_msecs(sbinfo->si_fhsm.fhsm_expire) / MSEC_PER_SEC;
++	if (u != AUFS_FHSM_CACHE_DEF_SEC)
++		seq_printf(seq, ",fhsm_sec=%u", u);
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/file.c linux-4.0.4/fs/aufs/file.c
+--- linux-4.0.4.orig/fs/aufs/file.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/file.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,831 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * handling file/dir, and address_space operation
++ */
++
++#ifdef CONFIG_AUFS_DEBUG
++#include <linux/migrate.h>
++#endif
++#include <linux/pagemap.h>
++#include "aufs.h"
++
++/* drop flags for writing */
++unsigned int au_file_roflags(unsigned int flags)
++{
++	flags &= ~(O_WRONLY | O_RDWR | O_APPEND | O_CREAT | O_TRUNC);
++	flags |= O_RDONLY | O_NOATIME;
++	return flags;
++}
++
++/* common functions to regular file and dir */
++struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
++		       struct file *file, int force_wr)
++{
++	struct file *h_file;
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++	struct super_block *sb;
++	struct au_branch *br;
++	struct path h_path;
++	int err;
++
++	/* a race condition can happen between open and unlink/rmdir */
++	h_file = ERR_PTR(-ENOENT);
++	h_dentry = au_h_dptr(dentry, bindex);
++	if (au_test_nfsd() && !h_dentry)
++		goto out;
++	h_inode = h_dentry->d_inode;
++	if (au_test_nfsd() && !h_inode)
++		goto out;
++	spin_lock(&h_dentry->d_lock);
++	err = (!d_unhashed(dentry) && d_unlinked(h_dentry))
++		|| !h_inode
++		/* || !dentry->d_inode->i_nlink */
++		;
++	spin_unlock(&h_dentry->d_lock);
++	if (unlikely(err))
++		goto out;
++
++	sb = dentry->d_sb;
++	br = au_sbr(sb, bindex);
++	err = au_br_test_oflag(flags, br);
++	h_file = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++
++	/* drop flags for writing */
++	if (au_test_ro(sb, bindex, dentry->d_inode)) {
++		if (force_wr && !(flags & O_WRONLY))
++			force_wr = 0;
++		flags = au_file_roflags(flags);
++		if (force_wr) {
++			h_file = ERR_PTR(-EROFS);
++			flags = au_file_roflags(flags);
++			if (unlikely(vfsub_native_ro(h_inode)
++				     || IS_APPEND(h_inode)))
++				goto out;
++			flags &= ~O_ACCMODE;
++			flags |= O_WRONLY;
++		}
++	}
++	flags &= ~O_CREAT;
++	atomic_inc(&br->br_count);
++	h_path.dentry = h_dentry;
++	h_path.mnt = au_br_mnt(br);
++	h_file = vfsub_dentry_open(&h_path, flags);
++	if (IS_ERR(h_file))
++		goto out_br;
++
++	if (flags & __FMODE_EXEC) {
++		err = deny_write_access(h_file);
++		if (unlikely(err)) {
++			fput(h_file);
++			h_file = ERR_PTR(err);
++			goto out_br;
++		}
++	}
++	fsnotify_open(h_file);
++	goto out; /* success */
++
++out_br:
++	atomic_dec(&br->br_count);
++out:
++	return h_file;
++}
++
++static int au_cmoo(struct dentry *dentry)
++{
++	int err, cmoo;
++	unsigned int udba;
++	struct path h_path;
++	struct au_pin pin;
++	struct au_cp_generic cpg = {
++		.dentry	= dentry,
++		.bdst	= -1,
++		.bsrc	= -1,
++		.len	= -1,
++		.pin	= &pin,
++		.flags	= AuCpup_DTIME | AuCpup_HOPEN
++	};
++	struct inode *delegated;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++	struct au_fhsm *fhsm;
++	pid_t pid;
++	struct au_branch *br;
++	struct dentry *parent;
++	struct au_hinode *hdir;
++
++	DiMustWriteLock(dentry);
++	IiMustWriteLock(dentry->d_inode);
++
++	err = 0;
++	if (IS_ROOT(dentry))
++		goto out;
++	cpg.bsrc = au_dbstart(dentry);
++	if (!cpg.bsrc)
++		goto out;
++
++	sb = dentry->d_sb;
++	sbinfo = au_sbi(sb);
++	fhsm = &sbinfo->si_fhsm;
++	pid = au_fhsm_pid(fhsm);
++	if (pid
++	    && (current->pid == pid
++		|| current->real_parent->pid == pid))
++		goto out;
++
++	br = au_sbr(sb, cpg.bsrc);
++	cmoo = au_br_cmoo(br->br_perm);
++	if (!cmoo)
++		goto out;
++	if (!d_is_reg(dentry))
++		cmoo &= AuBrAttr_COO_ALL;
++	if (!cmoo)
++		goto out;
++
++	parent = dget_parent(dentry);
++	di_write_lock_parent(parent);
++	err = au_wbr_do_copyup_bu(dentry, cpg.bsrc - 1);
++	cpg.bdst = err;
++	if (unlikely(err < 0)) {
++		err = 0;	/* there is no upper writable branch */
++		goto out_dgrade;
++	}
++	AuDbg("bsrc %d, bdst %d\n", cpg.bsrc, cpg.bdst);
++
++	/* do not respect the coo attrib for the target branch */
++	err = au_cpup_dirs(dentry, cpg.bdst);
++	if (unlikely(err))
++		goto out_dgrade;
++
++	di_downgrade_lock(parent, AuLock_IR);
++	udba = au_opt_udba(sb);
++	err = au_pin(&pin, dentry, cpg.bdst, udba,
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	if (unlikely(err))
++		goto out_parent;
++
++	err = au_sio_cpup_simple(&cpg);
++	au_unpin(&pin);
++	if (unlikely(err))
++		goto out_parent;
++	if (!(cmoo & AuBrWAttr_MOO))
++		goto out_parent; /* success */
++
++	err = au_pin(&pin, dentry, cpg.bsrc, udba,
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	if (unlikely(err))
++		goto out_parent;
++
++	h_path.mnt = au_br_mnt(br);
++	h_path.dentry = au_h_dptr(dentry, cpg.bsrc);
++	hdir = au_hi(parent->d_inode, cpg.bsrc);
++	delegated = NULL;
++	err = vfsub_unlink(hdir->hi_inode, &h_path, &delegated, /*force*/1);
++	au_unpin(&pin);
++	/* todo: keep h_dentry or not? */
++	if (unlikely(err == -EWOULDBLOCK)) {
++		pr_warn("cannot retry for NFSv4 delegation"
++			" for an internal unlink\n");
++		iput(delegated);
++	}
++	if (unlikely(err)) {
++		pr_err("unlink %pd after coo failed (%d), ignored\n",
++		       dentry, err);
++		err = 0;
++	}
++	goto out_parent; /* success */
++
++out_dgrade:
++	di_downgrade_lock(parent, AuLock_IR);
++out_parent:
++	di_read_unlock(parent, AuLock_IR);
++	dput(parent);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++int au_do_open(struct file *file, struct au_do_open_args *args)
++{
++	int err, no_lock = args->no_lock;
++	struct dentry *dentry;
++	struct au_finfo *finfo;
++
++	if (!no_lock)
++		err = au_finfo_init(file, args->fidir);
++	else {
++		lockdep_off();
++		err = au_finfo_init(file, args->fidir);
++		lockdep_on();
++	}
++	if (unlikely(err))
++		goto out;
++
++	dentry = file->f_path.dentry;
++	AuDebugOn(IS_ERR_OR_NULL(dentry));
++	if (!no_lock) {
++		di_write_lock_child(dentry);
++		err = au_cmoo(dentry);
++		di_downgrade_lock(dentry, AuLock_IR);
++		if (!err)
++			err = args->open(file, vfsub_file_flags(file), NULL);
++		di_read_unlock(dentry, AuLock_IR);
++	} else {
++		err = au_cmoo(dentry);
++		if (!err)
++			err = args->open(file, vfsub_file_flags(file),
++					 args->h_file);
++		if (!err && au_fbstart(file) != au_dbstart(dentry))
++			/*
++			 * cmoo happens after h_file was opened.
++			 * need to refresh file later.
++			 */
++			atomic_dec(&au_fi(file)->fi_generation);
++	}
++
++	finfo = au_fi(file);
++	if (!err) {
++		finfo->fi_file = file;
++		au_sphl_add(&finfo->fi_hlist,
++			    &au_sbi(file->f_path.dentry->d_sb)->si_files);
++	}
++	if (!no_lock)
++		fi_write_unlock(file);
++	else {
++		lockdep_off();
++		fi_write_unlock(file);
++		lockdep_on();
++	}
++	if (unlikely(err)) {
++		finfo->fi_hdir = NULL;
++		au_finfo_fin(file);
++	}
++
++out:
++	return err;
++}
++
++int au_reopen_nondir(struct file *file)
++{
++	int err;
++	aufs_bindex_t bstart;
++	struct dentry *dentry;
++	struct file *h_file, *h_file_tmp;
++
++	dentry = file->f_path.dentry;
++	bstart = au_dbstart(dentry);
++	h_file_tmp = NULL;
++	if (au_fbstart(file) == bstart) {
++		h_file = au_hf_top(file);
++		if (file->f_mode == h_file->f_mode)
++			return 0; /* success */
++		h_file_tmp = h_file;
++		get_file(h_file_tmp);
++		au_set_h_fptr(file, bstart, NULL);
++	}
++	AuDebugOn(au_fi(file)->fi_hdir);
++	/*
++	 * it can happen
++	 * file exists on both of rw and ro
++	 * open --> dbstart and fbstart are both 0
++	 * prepend a branch as rw, "rw" become ro
++	 * remove rw/file
++	 * delete the top branch, "rw" becomes rw again
++	 *	--> dbstart is 1, fbstart is still 0
++	 * write --> fbstart is 0 but dbstart is 1
++	 */
++	/* AuDebugOn(au_fbstart(file) < bstart); */
++
++	h_file = au_h_open(dentry, bstart, vfsub_file_flags(file) & ~O_TRUNC,
++			   file, /*force_wr*/0);
++	err = PTR_ERR(h_file);
++	if (IS_ERR(h_file)) {
++		if (h_file_tmp) {
++			atomic_inc(&au_sbr(dentry->d_sb, bstart)->br_count);
++			au_set_h_fptr(file, bstart, h_file_tmp);
++			h_file_tmp = NULL;
++		}
++		goto out; /* todo: close all? */
++	}
++
++	err = 0;
++	au_set_fbstart(file, bstart);
++	au_set_h_fptr(file, bstart, h_file);
++	au_update_figen(file);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++
++out:
++	if (h_file_tmp)
++		fput(h_file_tmp);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_reopen_wh(struct file *file, aufs_bindex_t btgt,
++			struct dentry *hi_wh)
++{
++	int err;
++	aufs_bindex_t bstart;
++	struct au_dinfo *dinfo;
++	struct dentry *h_dentry;
++	struct au_hdentry *hdp;
++
++	dinfo = au_di(file->f_path.dentry);
++	AuRwMustWriteLock(&dinfo->di_rwsem);
++
++	bstart = dinfo->di_bstart;
++	dinfo->di_bstart = btgt;
++	hdp = dinfo->di_hdentry;
++	h_dentry = hdp[0 + btgt].hd_dentry;
++	hdp[0 + btgt].hd_dentry = hi_wh;
++	err = au_reopen_nondir(file);
++	hdp[0 + btgt].hd_dentry = h_dentry;
++	dinfo->di_bstart = bstart;
++
++	return err;
++}
++
++static int au_ready_to_write_wh(struct file *file, loff_t len,
++				aufs_bindex_t bcpup, struct au_pin *pin)
++{
++	int err;
++	struct inode *inode, *h_inode;
++	struct dentry *h_dentry, *hi_wh;
++	struct au_cp_generic cpg = {
++		.dentry	= file->f_path.dentry,
++		.bdst	= bcpup,
++		.bsrc	= -1,
++		.len	= len,
++		.pin	= pin
++	};
++
++	au_update_dbstart(cpg.dentry);
++	inode = cpg.dentry->d_inode;
++	h_inode = NULL;
++	if (au_dbstart(cpg.dentry) <= bcpup
++	    && au_dbend(cpg.dentry) >= bcpup) {
++		h_dentry = au_h_dptr(cpg.dentry, bcpup);
++		if (h_dentry)
++			h_inode = h_dentry->d_inode;
++	}
++	hi_wh = au_hi_wh(inode, bcpup);
++	if (!hi_wh && !h_inode)
++		err = au_sio_cpup_wh(&cpg, file);
++	else
++		/* already copied-up after unlink */
++		err = au_reopen_wh(file, bcpup, hi_wh);
++
++	if (!err
++	    && (inode->i_nlink > 1
++		|| (inode->i_state & I_LINKABLE))
++	    && au_opt_test(au_mntflags(cpg.dentry->d_sb), PLINK))
++		au_plink_append(inode, bcpup, au_h_dptr(cpg.dentry, bcpup));
++
++	return err;
++}
++
++/*
++ * prepare the @file for writing.
++ */
++int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin)
++{
++	int err;
++	aufs_bindex_t dbstart;
++	struct dentry *parent;
++	struct inode *inode;
++	struct super_block *sb;
++	struct file *h_file;
++	struct au_cp_generic cpg = {
++		.dentry	= file->f_path.dentry,
++		.bdst	= -1,
++		.bsrc	= -1,
++		.len	= len,
++		.pin	= pin,
++		.flags	= AuCpup_DTIME
++	};
++
++	sb = cpg.dentry->d_sb;
++	inode = cpg.dentry->d_inode;
++	cpg.bsrc = au_fbstart(file);
++	err = au_test_ro(sb, cpg.bsrc, inode);
++	if (!err && (au_hf_top(file)->f_mode & FMODE_WRITE)) {
++		err = au_pin(pin, cpg.dentry, cpg.bsrc, AuOpt_UDBA_NONE,
++			     /*flags*/0);
++		goto out;
++	}
++
++	/* need to cpup or reopen */
++	parent = dget_parent(cpg.dentry);
++	di_write_lock_parent(parent);
++	err = AuWbrCopyup(au_sbi(sb), cpg.dentry);
++	cpg.bdst = err;
++	if (unlikely(err < 0))
++		goto out_dgrade;
++	err = 0;
++
++	if (!d_unhashed(cpg.dentry) && !au_h_dptr(parent, cpg.bdst)) {
++		err = au_cpup_dirs(cpg.dentry, cpg.bdst);
++		if (unlikely(err))
++			goto out_dgrade;
++	}
++
++	err = au_pin(pin, cpg.dentry, cpg.bdst, AuOpt_UDBA_NONE,
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	if (unlikely(err))
++		goto out_dgrade;
++
++	dbstart = au_dbstart(cpg.dentry);
++	if (dbstart <= cpg.bdst)
++		cpg.bsrc = cpg.bdst;
++
++	if (dbstart <= cpg.bdst		/* just reopen */
++	    || !d_unhashed(cpg.dentry)	/* copyup and reopen */
++		) {
++		h_file = au_h_open_pre(cpg.dentry, cpg.bsrc, /*force_wr*/0);
++		if (IS_ERR(h_file))
++			err = PTR_ERR(h_file);
++		else {
++			di_downgrade_lock(parent, AuLock_IR);
++			if (dbstart > cpg.bdst)
++				err = au_sio_cpup_simple(&cpg);
++			if (!err)
++				err = au_reopen_nondir(file);
++			au_h_open_post(cpg.dentry, cpg.bsrc, h_file);
++		}
++	} else {			/* copyup as wh and reopen */
++		/*
++		 * since writable hfsplus branch is not supported,
++		 * h_open_pre/post() are unnecessary.
++		 */
++		err = au_ready_to_write_wh(file, len, cpg.bdst, pin);
++		di_downgrade_lock(parent, AuLock_IR);
++	}
++
++	if (!err) {
++		au_pin_set_parent_lflag(pin, /*lflag*/0);
++		goto out_dput; /* success */
++	}
++	au_unpin(pin);
++	goto out_unlock;
++
++out_dgrade:
++	di_downgrade_lock(parent, AuLock_IR);
++out_unlock:
++	di_read_unlock(parent, AuLock_IR);
++out_dput:
++	dput(parent);
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_do_flush(struct file *file, fl_owner_t id,
++		int (*flush)(struct file *file, fl_owner_t id))
++{
++	int err;
++	struct super_block *sb;
++	struct inode *inode;
++
++	inode = file_inode(file);
++	sb = inode->i_sb;
++	si_noflush_read_lock(sb);
++	fi_read_lock(file);
++	ii_read_lock_child(inode);
++
++	err = flush(file, id);
++	au_cpup_attr_timesizes(inode);
++
++	ii_read_unlock(inode);
++	fi_read_unlock(file);
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_file_refresh_by_inode(struct file *file, int *need_reopen)
++{
++	int err;
++	struct au_pin pin;
++	struct au_finfo *finfo;
++	struct dentry *parent, *hi_wh;
++	struct inode *inode;
++	struct super_block *sb;
++	struct au_cp_generic cpg = {
++		.dentry	= file->f_path.dentry,
++		.bdst	= -1,
++		.bsrc	= -1,
++		.len	= -1,
++		.pin	= &pin,
++		.flags	= AuCpup_DTIME
++	};
++
++	FiMustWriteLock(file);
++
++	err = 0;
++	finfo = au_fi(file);
++	sb = cpg.dentry->d_sb;
++	inode = cpg.dentry->d_inode;
++	cpg.bdst = au_ibstart(inode);
++	if (cpg.bdst == finfo->fi_btop || IS_ROOT(cpg.dentry))
++		goto out;
++
++	parent = dget_parent(cpg.dentry);
++	if (au_test_ro(sb, cpg.bdst, inode)) {
++		di_read_lock_parent(parent, !AuLock_IR);
++		err = AuWbrCopyup(au_sbi(sb), cpg.dentry);
++		cpg.bdst = err;
++		di_read_unlock(parent, !AuLock_IR);
++		if (unlikely(err < 0))
++			goto out_parent;
++		err = 0;
++	}
++
++	di_read_lock_parent(parent, AuLock_IR);
++	hi_wh = au_hi_wh(inode, cpg.bdst);
++	if (!S_ISDIR(inode->i_mode)
++	    && au_opt_test(au_mntflags(sb), PLINK)
++	    && au_plink_test(inode)
++	    && !d_unhashed(cpg.dentry)
++	    && cpg.bdst < au_dbstart(cpg.dentry)) {
++		err = au_test_and_cpup_dirs(cpg.dentry, cpg.bdst);
++		if (unlikely(err))
++			goto out_unlock;
++
++		/* always superio. */
++		err = au_pin(&pin, cpg.dentry, cpg.bdst, AuOpt_UDBA_NONE,
++			     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++		if (!err) {
++			err = au_sio_cpup_simple(&cpg);
++			au_unpin(&pin);
++		}
++	} else if (hi_wh) {
++		/* already copied-up after unlink */
++		err = au_reopen_wh(file, cpg.bdst, hi_wh);
++		*need_reopen = 0;
++	}
++
++out_unlock:
++	di_read_unlock(parent, AuLock_IR);
++out_parent:
++	dput(parent);
++out:
++	return err;
++}
++
++static void au_do_refresh_dir(struct file *file)
++{
++	aufs_bindex_t bindex, bend, new_bindex, brid;
++	struct au_hfile *p, tmp, *q;
++	struct au_finfo *finfo;
++	struct super_block *sb;
++	struct au_fidir *fidir;
++
++	FiMustWriteLock(file);
++
++	sb = file->f_path.dentry->d_sb;
++	finfo = au_fi(file);
++	fidir = finfo->fi_hdir;
++	AuDebugOn(!fidir);
++	p = fidir->fd_hfile + finfo->fi_btop;
++	brid = p->hf_br->br_id;
++	bend = fidir->fd_bbot;
++	for (bindex = finfo->fi_btop; bindex <= bend; bindex++, p++) {
++		if (!p->hf_file)
++			continue;
++
++		new_bindex = au_br_index(sb, p->hf_br->br_id);
++		if (new_bindex == bindex)
++			continue;
++		if (new_bindex < 0) {
++			au_set_h_fptr(file, bindex, NULL);
++			continue;
++		}
++
++		/* swap two lower inode, and loop again */
++		q = fidir->fd_hfile + new_bindex;
++		tmp = *q;
++		*q = *p;
++		*p = tmp;
++		if (tmp.hf_file) {
++			bindex--;
++			p--;
++		}
++	}
++
++	p = fidir->fd_hfile;
++	if (!au_test_mmapped(file) && !d_unlinked(file->f_path.dentry)) {
++		bend = au_sbend(sb);
++		for (finfo->fi_btop = 0; finfo->fi_btop <= bend;
++		     finfo->fi_btop++, p++)
++			if (p->hf_file) {
++				if (file_inode(p->hf_file))
++					break;
++				au_hfput(p, file);
++			}
++	} else {
++		bend = au_br_index(sb, brid);
++		for (finfo->fi_btop = 0; finfo->fi_btop < bend;
++		     finfo->fi_btop++, p++)
++			if (p->hf_file)
++				au_hfput(p, file);
++		bend = au_sbend(sb);
++	}
++
++	p = fidir->fd_hfile + bend;
++	for (fidir->fd_bbot = bend; fidir->fd_bbot >= finfo->fi_btop;
++	     fidir->fd_bbot--, p--)
++		if (p->hf_file) {
++			if (file_inode(p->hf_file))
++				break;
++			au_hfput(p, file);
++		}
++	AuDebugOn(fidir->fd_bbot < finfo->fi_btop);
++}
++
++/*
++ * after branch manipulating, refresh the file.
++ */
++static int refresh_file(struct file *file, int (*reopen)(struct file *file))
++{
++	int err, need_reopen;
++	aufs_bindex_t bend, bindex;
++	struct dentry *dentry;
++	struct au_finfo *finfo;
++	struct au_hfile *hfile;
++
++	dentry = file->f_path.dentry;
++	finfo = au_fi(file);
++	if (!finfo->fi_hdir) {
++		hfile = &finfo->fi_htop;
++		AuDebugOn(!hfile->hf_file);
++		bindex = au_br_index(dentry->d_sb, hfile->hf_br->br_id);
++		AuDebugOn(bindex < 0);
++		if (bindex != finfo->fi_btop)
++			au_set_fbstart(file, bindex);
++	} else {
++		err = au_fidir_realloc(finfo, au_sbend(dentry->d_sb) + 1);
++		if (unlikely(err))
++			goto out;
++		au_do_refresh_dir(file);
++	}
++
++	err = 0;
++	need_reopen = 1;
++	if (!au_test_mmapped(file))
++		err = au_file_refresh_by_inode(file, &need_reopen);
++	if (!err && need_reopen && !d_unlinked(dentry))
++		err = reopen(file);
++	if (!err) {
++		au_update_figen(file);
++		goto out; /* success */
++	}
++
++	/* error, close all lower files */
++	if (finfo->fi_hdir) {
++		bend = au_fbend_dir(file);
++		for (bindex = au_fbstart(file); bindex <= bend; bindex++)
++			au_set_h_fptr(file, bindex, NULL);
++	}
++
++out:
++	return err;
++}
++
++/* common function to regular file and dir */
++int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
++			  int wlock)
++{
++	int err;
++	unsigned int sigen, figen;
++	aufs_bindex_t bstart;
++	unsigned char pseudo_link;
++	struct dentry *dentry;
++	struct inode *inode;
++
++	err = 0;
++	dentry = file->f_path.dentry;
++	inode = dentry->d_inode;
++	sigen = au_sigen(dentry->d_sb);
++	fi_write_lock(file);
++	figen = au_figen(file);
++	di_write_lock_child(dentry);
++	bstart = au_dbstart(dentry);
++	pseudo_link = (bstart != au_ibstart(inode));
++	if (sigen == figen && !pseudo_link && au_fbstart(file) == bstart) {
++		if (!wlock) {
++			di_downgrade_lock(dentry, AuLock_IR);
++			fi_downgrade_lock(file);
++		}
++		goto out; /* success */
++	}
++
++	AuDbg("sigen %d, figen %d\n", sigen, figen);
++	if (au_digen_test(dentry, sigen)) {
++		err = au_reval_dpath(dentry, sigen);
++		AuDebugOn(!err && au_digen_test(dentry, sigen));
++	}
++
++	if (!err)
++		err = refresh_file(file, reopen);
++	if (!err) {
++		if (!wlock) {
++			di_downgrade_lock(dentry, AuLock_IR);
++			fi_downgrade_lock(file);
++		}
++	} else {
++		di_write_unlock(dentry);
++		fi_write_unlock(file);
++	}
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* cf. aufs_nopage() */
++/* for madvise(2) */
++static int aufs_readpage(struct file *file __maybe_unused, struct page *page)
++{
++	unlock_page(page);
++	return 0;
++}
++
++/* it will never be called, but necessary to support O_DIRECT */
++static ssize_t aufs_direct_IO(int rw, struct kiocb *iocb,
++			      struct iov_iter *iter, loff_t offset)
++{ BUG(); return 0; }
++
++/* they will never be called. */
++#ifdef CONFIG_AUFS_DEBUG
++static int aufs_write_begin(struct file *file, struct address_space *mapping,
++			    loff_t pos, unsigned len, unsigned flags,
++			    struct page **pagep, void **fsdata)
++{ AuUnsupport(); return 0; }
++static int aufs_write_end(struct file *file, struct address_space *mapping,
++			  loff_t pos, unsigned len, unsigned copied,
++			  struct page *page, void *fsdata)
++{ AuUnsupport(); return 0; }
++static int aufs_writepage(struct page *page, struct writeback_control *wbc)
++{ AuUnsupport(); return 0; }
++
++static int aufs_set_page_dirty(struct page *page)
++{ AuUnsupport(); return 0; }
++static void aufs_invalidatepage(struct page *page, unsigned int offset,
++				unsigned int length)
++{ AuUnsupport(); }
++static int aufs_releasepage(struct page *page, gfp_t gfp)
++{ AuUnsupport(); return 0; }
++static int aufs_migratepage(struct address_space *mapping, struct page *newpage,
++			    struct page *page, enum migrate_mode mode)
++{ AuUnsupport(); return 0; }
++static int aufs_launder_page(struct page *page)
++{ AuUnsupport(); return 0; }
++static int aufs_is_partially_uptodate(struct page *page,
++				      unsigned long from,
++				      unsigned long count)
++{ AuUnsupport(); return 0; }
++static void aufs_is_dirty_writeback(struct page *page, bool *dirty,
++				    bool *writeback)
++{ AuUnsupport(); }
++static int aufs_error_remove_page(struct address_space *mapping,
++				  struct page *page)
++{ AuUnsupport(); return 0; }
++static int aufs_swap_activate(struct swap_info_struct *sis, struct file *file,
++			      sector_t *span)
++{ AuUnsupport(); return 0; }
++static void aufs_swap_deactivate(struct file *file)
++{ AuUnsupport(); }
++#endif /* CONFIG_AUFS_DEBUG */
++
++const struct address_space_operations aufs_aop = {
++	.readpage		= aufs_readpage,
++	.direct_IO		= aufs_direct_IO,
++#ifdef CONFIG_AUFS_DEBUG
++	.writepage		= aufs_writepage,
++	/* no writepages, because of writepage */
++	.set_page_dirty		= aufs_set_page_dirty,
++	/* no readpages, because of readpage */
++	.write_begin		= aufs_write_begin,
++	.write_end		= aufs_write_end,
++	/* no bmap, no block device */
++	.invalidatepage		= aufs_invalidatepage,
++	.releasepage		= aufs_releasepage,
++	.migratepage		= aufs_migratepage,
++	.launder_page		= aufs_launder_page,
++	.is_partially_uptodate	= aufs_is_partially_uptodate,
++	.is_dirty_writeback	= aufs_is_dirty_writeback,
++	.error_remove_page	= aufs_error_remove_page,
++	.swap_activate		= aufs_swap_activate,
++	.swap_deactivate	= aufs_swap_deactivate
++#endif /* CONFIG_AUFS_DEBUG */
++};
+diff -Nur linux-4.0.4.orig/fs/aufs/file.h linux-4.0.4/fs/aufs/file.h
+--- linux-4.0.4.orig/fs/aufs/file.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/file.h	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,277 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * file operations
++ */
++
++#ifndef __AUFS_FILE_H__
++#define __AUFS_FILE_H__
++
++#ifdef __KERNEL__
++
++#include <linux/file.h>
++#include <linux/fs.h>
++#include <linux/poll.h>
++#include "rwsem.h"
++
++struct au_branch;
++struct au_hfile {
++	struct file		*hf_file;
++	struct au_branch	*hf_br;
++};
++
++struct au_vdir;
++struct au_fidir {
++	aufs_bindex_t		fd_bbot;
++	aufs_bindex_t		fd_nent;
++	struct au_vdir		*fd_vdir_cache;
++	struct au_hfile		fd_hfile[];
++};
++
++static inline int au_fidir_sz(int nent)
++{
++	AuDebugOn(nent < 0);
++	return sizeof(struct au_fidir) + sizeof(struct au_hfile) * nent;
++}
++
++struct au_finfo {
++	atomic_t		fi_generation;
++
++	struct au_rwsem		fi_rwsem;
++	aufs_bindex_t		fi_btop;
++
++	/* do not union them */
++	struct {				/* for non-dir */
++		struct au_hfile			fi_htop;
++		atomic_t			fi_mmapped;
++	};
++	struct au_fidir		*fi_hdir;	/* for dir only */
++
++	struct hlist_node	fi_hlist;
++	struct file		*fi_file;	/* very ugly */
++} ____cacheline_aligned_in_smp;
++
++/* ---------------------------------------------------------------------- */
++
++/* file.c */
++extern const struct address_space_operations aufs_aop;
++unsigned int au_file_roflags(unsigned int flags);
++struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
++		       struct file *file, int force_wr);
++struct au_do_open_args {
++	int		no_lock;
++	int		(*open)(struct file *file, int flags,
++				struct file *h_file);
++	struct au_fidir	*fidir;
++	struct file	*h_file;
++};
++int au_do_open(struct file *file, struct au_do_open_args *args);
++int au_reopen_nondir(struct file *file);
++struct au_pin;
++int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin);
++int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
++			  int wlock);
++int au_do_flush(struct file *file, fl_owner_t id,
++		int (*flush)(struct file *file, fl_owner_t id));
++
++/* poll.c */
++#ifdef CONFIG_AUFS_POLL
++unsigned int aufs_poll(struct file *file, poll_table *wait);
++#endif
++
++#ifdef CONFIG_AUFS_BR_HFSPLUS
++/* hfsplus.c */
++struct file *au_h_open_pre(struct dentry *dentry, aufs_bindex_t bindex,
++			   int force_wr);
++void au_h_open_post(struct dentry *dentry, aufs_bindex_t bindex,
++		    struct file *h_file);
++#else
++AuStub(struct file *, au_h_open_pre, return NULL, struct dentry *dentry,
++       aufs_bindex_t bindex, int force_wr)
++AuStubVoid(au_h_open_post, struct dentry *dentry, aufs_bindex_t bindex,
++	   struct file *h_file);
++#endif
++
++/* f_op.c */
++extern const struct file_operations aufs_file_fop;
++int au_do_open_nondir(struct file *file, int flags, struct file *h_file);
++int aufs_release_nondir(struct inode *inode __maybe_unused, struct file *file);
++
++/* finfo.c */
++void au_hfput(struct au_hfile *hf, struct file *file);
++void au_set_h_fptr(struct file *file, aufs_bindex_t bindex,
++		   struct file *h_file);
++
++void au_update_figen(struct file *file);
++struct au_fidir *au_fidir_alloc(struct super_block *sb);
++int au_fidir_realloc(struct au_finfo *finfo, int nbr);
++
++void au_fi_init_once(void *_fi);
++void au_finfo_fin(struct file *file);
++int au_finfo_init(struct file *file, struct au_fidir *fidir);
++
++/* ioctl.c */
++long aufs_ioctl_nondir(struct file *file, unsigned int cmd, unsigned long arg);
++#ifdef CONFIG_COMPAT
++long aufs_compat_ioctl_dir(struct file *file, unsigned int cmd,
++			   unsigned long arg);
++long aufs_compat_ioctl_nondir(struct file *file, unsigned int cmd,
++			      unsigned long arg);
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct au_finfo *au_fi(struct file *file)
++{
++	return file->private_data;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * fi_read_lock, fi_write_lock,
++ * fi_read_unlock, fi_write_unlock, fi_downgrade_lock
++ */
++AuSimpleRwsemFuncs(fi, struct file *f, &au_fi(f)->fi_rwsem);
++
++#define FiMustNoWaiters(f)	AuRwMustNoWaiters(&au_fi(f)->fi_rwsem)
++#define FiMustAnyLock(f)	AuRwMustAnyLock(&au_fi(f)->fi_rwsem)
++#define FiMustWriteLock(f)	AuRwMustWriteLock(&au_fi(f)->fi_rwsem)
++
++/* ---------------------------------------------------------------------- */
++
++/* todo: hard/soft set? */
++static inline aufs_bindex_t au_fbstart(struct file *file)
++{
++	FiMustAnyLock(file);
++	return au_fi(file)->fi_btop;
++}
++
++static inline aufs_bindex_t au_fbend_dir(struct file *file)
++{
++	FiMustAnyLock(file);
++	AuDebugOn(!au_fi(file)->fi_hdir);
++	return au_fi(file)->fi_hdir->fd_bbot;
++}
++
++static inline struct au_vdir *au_fvdir_cache(struct file *file)
++{
++	FiMustAnyLock(file);
++	AuDebugOn(!au_fi(file)->fi_hdir);
++	return au_fi(file)->fi_hdir->fd_vdir_cache;
++}
++
++static inline void au_set_fbstart(struct file *file, aufs_bindex_t bindex)
++{
++	FiMustWriteLock(file);
++	au_fi(file)->fi_btop = bindex;
++}
++
++static inline void au_set_fbend_dir(struct file *file, aufs_bindex_t bindex)
++{
++	FiMustWriteLock(file);
++	AuDebugOn(!au_fi(file)->fi_hdir);
++	au_fi(file)->fi_hdir->fd_bbot = bindex;
++}
++
++static inline void au_set_fvdir_cache(struct file *file,
++				      struct au_vdir *vdir_cache)
++{
++	FiMustWriteLock(file);
++	AuDebugOn(!au_fi(file)->fi_hdir);
++	au_fi(file)->fi_hdir->fd_vdir_cache = vdir_cache;
++}
++
++static inline struct file *au_hf_top(struct file *file)
++{
++	FiMustAnyLock(file);
++	AuDebugOn(au_fi(file)->fi_hdir);
++	return au_fi(file)->fi_htop.hf_file;
++}
++
++static inline struct file *au_hf_dir(struct file *file, aufs_bindex_t bindex)
++{
++	FiMustAnyLock(file);
++	AuDebugOn(!au_fi(file)->fi_hdir);
++	return au_fi(file)->fi_hdir->fd_hfile[0 + bindex].hf_file;
++}
++
++/* todo: memory barrier? */
++static inline unsigned int au_figen(struct file *f)
++{
++	return atomic_read(&au_fi(f)->fi_generation);
++}
++
++static inline void au_set_mmapped(struct file *f)
++{
++	if (atomic_inc_return(&au_fi(f)->fi_mmapped))
++		return;
++	pr_warn("fi_mmapped wrapped around\n");
++	while (!atomic_inc_return(&au_fi(f)->fi_mmapped))
++		;
++}
++
++static inline void au_unset_mmapped(struct file *f)
++{
++	atomic_dec(&au_fi(f)->fi_mmapped);
++}
++
++static inline int au_test_mmapped(struct file *f)
++{
++	return atomic_read(&au_fi(f)->fi_mmapped);
++}
++
++/* customize vma->vm_file */
++
++static inline void au_do_vm_file_reset(struct vm_area_struct *vma,
++				       struct file *file)
++{
++	struct file *f;
++
++	f = vma->vm_file;
++	get_file(file);
++	vma->vm_file = file;
++	fput(f);
++}
++
++#ifdef CONFIG_MMU
++#define AuDbgVmRegion(file, vma) do {} while (0)
++
++static inline void au_vm_file_reset(struct vm_area_struct *vma,
++				    struct file *file)
++{
++	au_do_vm_file_reset(vma, file);
++}
++#else
++#define AuDbgVmRegion(file, vma) \
++	AuDebugOn((vma)->vm_region && (vma)->vm_region->vm_file != (file))
++
++static inline void au_vm_file_reset(struct vm_area_struct *vma,
++				    struct file *file)
++{
++	struct file *f;
++
++	au_do_vm_file_reset(vma, file);
++	f = vma->vm_region->vm_file;
++	get_file(file);
++	vma->vm_region->vm_file = file;
++	fput(f);
++}
++#endif /* CONFIG_MMU */
++
++/* handle vma->vm_prfile */
++static inline void au_vm_prfile_set(struct vm_area_struct *vma,
++				    struct file *file)
++{
++	get_file(file);
++	vma->vm_prfile = file;
++#ifndef CONFIG_MMU
++	get_file(file);
++	vma->vm_region->vm_prfile = file;
++#endif
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_FILE_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/finfo.c linux-4.0.4/fs/aufs/finfo.c
+--- linux-4.0.4.orig/fs/aufs/finfo.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/finfo.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,144 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * file private data
++ */
++
++#include "aufs.h"
++
++void au_hfput(struct au_hfile *hf, struct file *file)
++{
++	/* todo: direct access f_flags */
++	if (vfsub_file_flags(file) & __FMODE_EXEC)
++		allow_write_access(hf->hf_file);
++	fput(hf->hf_file);
++	hf->hf_file = NULL;
++	atomic_dec(&hf->hf_br->br_count);
++	hf->hf_br = NULL;
++}
++
++void au_set_h_fptr(struct file *file, aufs_bindex_t bindex, struct file *val)
++{
++	struct au_finfo *finfo = au_fi(file);
++	struct au_hfile *hf;
++	struct au_fidir *fidir;
++
++	fidir = finfo->fi_hdir;
++	if (!fidir) {
++		AuDebugOn(finfo->fi_btop != bindex);
++		hf = &finfo->fi_htop;
++	} else
++		hf = fidir->fd_hfile + bindex;
++
++	if (hf && hf->hf_file)
++		au_hfput(hf, file);
++	if (val) {
++		FiMustWriteLock(file);
++		AuDebugOn(IS_ERR_OR_NULL(file->f_path.dentry));
++		hf->hf_file = val;
++		hf->hf_br = au_sbr(file->f_path.dentry->d_sb, bindex);
++	}
++}
++
++void au_update_figen(struct file *file)
++{
++	atomic_set(&au_fi(file)->fi_generation, au_digen(file->f_path.dentry));
++	/* smp_mb(); */ /* atomic_set */
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_fidir *au_fidir_alloc(struct super_block *sb)
++{
++	struct au_fidir *fidir;
++	int nbr;
++
++	nbr = au_sbend(sb) + 1;
++	if (nbr < 2)
++		nbr = 2; /* initial allocate for 2 branches */
++	fidir = kzalloc(au_fidir_sz(nbr), GFP_NOFS);
++	if (fidir) {
++		fidir->fd_bbot = -1;
++		fidir->fd_nent = nbr;
++		fidir->fd_vdir_cache = NULL;
++	}
++
++	return fidir;
++}
++
++int au_fidir_realloc(struct au_finfo *finfo, int nbr)
++{
++	int err;
++	struct au_fidir *fidir, *p;
++
++	AuRwMustWriteLock(&finfo->fi_rwsem);
++	fidir = finfo->fi_hdir;
++	AuDebugOn(!fidir);
++
++	err = -ENOMEM;
++	p = au_kzrealloc(fidir, au_fidir_sz(fidir->fd_nent), au_fidir_sz(nbr),
++			 GFP_NOFS);
++	if (p) {
++		p->fd_nent = nbr;
++		finfo->fi_hdir = p;
++		err = 0;
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_finfo_fin(struct file *file)
++{
++	struct au_finfo *finfo;
++
++	au_nfiles_dec(file->f_path.dentry->d_sb);
++
++	finfo = au_fi(file);
++	AuDebugOn(finfo->fi_hdir);
++	AuRwDestroy(&finfo->fi_rwsem);
++	au_cache_free_finfo(finfo);
++}
++
++void au_fi_init_once(void *_finfo)
++{
++	struct au_finfo *finfo = _finfo;
++	static struct lock_class_key aufs_fi;
++
++	au_rw_init(&finfo->fi_rwsem);
++	au_rw_class(&finfo->fi_rwsem, &aufs_fi);
++}
++
++int au_finfo_init(struct file *file, struct au_fidir *fidir)
++{
++	int err;
++	struct au_finfo *finfo;
++	struct dentry *dentry;
++
++	err = -ENOMEM;
++	dentry = file->f_path.dentry;
++	finfo = au_cache_alloc_finfo();
++	if (unlikely(!finfo))
++		goto out;
++
++	err = 0;
++	au_nfiles_inc(dentry->d_sb);
++	/* verbose coding for lock class name */
++	if (!fidir)
++		au_rw_class(&finfo->fi_rwsem, au_lc_key + AuLcNonDir_FIINFO);
++	else
++		au_rw_class(&finfo->fi_rwsem, au_lc_key + AuLcDir_FIINFO);
++	au_rw_write_lock(&finfo->fi_rwsem);
++	finfo->fi_btop = -1;
++	finfo->fi_hdir = fidir;
++	atomic_set(&finfo->fi_generation, au_digen(dentry));
++	/* smp_mb(); */ /* atomic_set */
++
++	file->private_data = finfo;
++
++out:
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/f_op.c linux-4.0.4/fs/aufs/f_op.c
+--- linux-4.0.4.orig/fs/aufs/f_op.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/f_op.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,807 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * file and vm operations
++ */
++
++#include <linux/aio.h>
++#include <linux/fs_stack.h>
++#include <linux/mman.h>
++#include <linux/security.h>
++#include "aufs.h"
++
++int au_do_open_nondir(struct file *file, int flags, struct file *h_file)
++{
++	int err;
++	aufs_bindex_t bindex;
++	struct dentry *dentry;
++	struct au_finfo *finfo;
++	struct inode *h_inode;
++
++	FiMustWriteLock(file);
++
++	err = 0;
++	dentry = file->f_path.dentry;
++	AuDebugOn(IS_ERR_OR_NULL(dentry));
++	finfo = au_fi(file);
++	memset(&finfo->fi_htop, 0, sizeof(finfo->fi_htop));
++	atomic_set(&finfo->fi_mmapped, 0);
++	bindex = au_dbstart(dentry);
++	if (!h_file)
++		h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
++	else
++		get_file(h_file);
++	if (IS_ERR(h_file))
++		err = PTR_ERR(h_file);
++	else {
++		if ((flags & __O_TMPFILE)
++		    && !(flags & O_EXCL)) {
++			h_inode = file_inode(h_file);
++			spin_lock(&h_inode->i_lock);
++			h_inode->i_state |= I_LINKABLE;
++			spin_unlock(&h_inode->i_lock);
++		}
++		au_set_fbstart(file, bindex);
++		au_set_h_fptr(file, bindex, h_file);
++		au_update_figen(file);
++		/* todo: necessary? */
++		/* file->f_ra = h_file->f_ra; */
++	}
++
++	return err;
++}
++
++static int aufs_open_nondir(struct inode *inode __maybe_unused,
++			    struct file *file)
++{
++	int err;
++	struct super_block *sb;
++	struct au_do_open_args args = {
++		.open	= au_do_open_nondir
++	};
++
++	AuDbg("%pD, f_flags 0x%x, f_mode 0x%x\n",
++	      file, vfsub_file_flags(file), file->f_mode);
++
++	sb = file->f_path.dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	err = au_do_open(file, &args);
++	si_read_unlock(sb);
++	return err;
++}
++
++int aufs_release_nondir(struct inode *inode __maybe_unused, struct file *file)
++{
++	struct au_finfo *finfo;
++	aufs_bindex_t bindex;
++
++	finfo = au_fi(file);
++	au_sphl_del(&finfo->fi_hlist,
++		    &au_sbi(file->f_path.dentry->d_sb)->si_files);
++	bindex = finfo->fi_btop;
++	if (bindex >= 0)
++		au_set_h_fptr(file, bindex, NULL);
++
++	au_finfo_fin(file);
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_do_flush_nondir(struct file *file, fl_owner_t id)
++{
++	int err;
++	struct file *h_file;
++
++	err = 0;
++	h_file = au_hf_top(file);
++	if (h_file)
++		err = vfsub_flush(h_file, id);
++	return err;
++}
++
++static int aufs_flush_nondir(struct file *file, fl_owner_t id)
++{
++	return au_do_flush(file, id, au_do_flush_nondir);
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * read and write functions acquire [fdi]_rwsem once, but release before
++ * mmap_sem. This is because to stop a race condition between mmap(2).
++ * Releasing these aufs-rwsem should be safe, no branch-mamagement (by keeping
++ * si_rwsem), no harmful copy-up should happen. Actually copy-up may happen in
++ * read functions after [fdi]_rwsem are released, but it should be harmless.
++ */
++
++static ssize_t aufs_read(struct file *file, char __user *buf, size_t count,
++			 loff_t *ppos)
++{
++	ssize_t err;
++	struct dentry *dentry;
++	struct file *h_file;
++	struct super_block *sb;
++
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	h_file = au_hf_top(file);
++	get_file(h_file);
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++
++	/* filedata may be obsoleted by concurrent copyup, but no problem */
++	err = vfsub_read_u(h_file, buf, count, ppos);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++	/* update without lock, I don't think it a problem */
++	fsstack_copy_attr_atime(dentry->d_inode, file_inode(h_file));
++	fput(h_file);
++
++out:
++	si_read_unlock(sb);
++	return err;
++}
++
++/*
++ * todo: very ugly
++ * it locks both of i_mutex and si_rwsem for read in safe.
++ * if the plink maintenance mode continues forever (that is the problem),
++ * may loop forever.
++ */
++static void au_mtx_and_read_lock(struct inode *inode)
++{
++	int err;
++	struct super_block *sb = inode->i_sb;
++
++	while (1) {
++		mutex_lock(&inode->i_mutex);
++		err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++		if (!err)
++			break;
++		mutex_unlock(&inode->i_mutex);
++		si_read_lock(sb, AuLock_NOPLMW);
++		si_read_unlock(sb);
++	}
++}
++
++static ssize_t aufs_write(struct file *file, const char __user *ubuf,
++			  size_t count, loff_t *ppos)
++{
++	ssize_t err;
++	blkcnt_t blks;
++	aufs_bindex_t bstart;
++	struct au_pin pin;
++	struct dentry *dentry;
++	struct inode *inode, *h_inode;
++	struct super_block *sb;
++	struct file *h_file;
++	char __user *buf = (char __user *)ubuf;
++
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	au_mtx_and_read_lock(inode);
++
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err)) {
++		di_read_unlock(dentry, AuLock_IR);
++		fi_write_unlock(file);
++		goto out;
++	}
++
++	bstart = au_fbstart(file);
++	h_file = au_hf_top(file);
++	get_file(h_file);
++	h_inode = file_inode(h_file);
++	blks = h_inode->i_blocks;
++	au_unpin(&pin);
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++
++	err = vfsub_write_u(h_file, buf, count, ppos);
++	ii_write_lock_child(inode);
++	au_cpup_attr_timesizes(inode);
++	inode->i_mode = file_inode(h_file)->i_mode;
++	AuDbg("blks %llu, %llu\n", (u64)blks, (u64)h_inode->i_blocks);
++	if (err > 0)
++		au_fhsm_wrote(sb, bstart, /*force*/h_inode->i_blocks > blks);
++	ii_write_unlock(inode);
++	fput(h_file);
++
++out:
++	si_read_unlock(sb);
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
++
++static ssize_t au_do_iter(struct file *h_file, int rw, struct kiocb *kio,
++			  struct iov_iter *iov_iter)
++{
++	ssize_t err;
++	struct file *file;
++	ssize_t (*iter)(struct kiocb *, struct iov_iter *);
++	ssize_t (*aio)(struct kiocb *, const struct iovec *, unsigned long,
++		       loff_t);
++
++	err = security_file_permission(h_file, rw);
++	if (unlikely(err))
++		goto out;
++
++	err = -ENOSYS;
++	iter = NULL;
++	aio = NULL;
++	if (rw == MAY_READ) {
++		iter = h_file->f_op->read_iter;
++		aio = h_file->f_op->aio_read;
++	} else if (rw == MAY_WRITE) {
++		iter = h_file->f_op->write_iter;
++		aio = h_file->f_op->aio_write;
++	}
++
++	file = kio->ki_filp;
++	kio->ki_filp = h_file;
++	if (iter) {
++		lockdep_off();
++		err = iter(kio, iov_iter);
++		lockdep_on();
++	} else if (aio) {
++		lockdep_off();
++		err = aio(kio, iov_iter->iov, iov_iter->nr_segs, kio->ki_pos);
++		lockdep_on();
++	} else
++		/* currently there is no such fs */
++		WARN_ON_ONCE(1);
++	kio->ki_filp = file;
++
++out:
++	return err;
++}
++
++static ssize_t aufs_read_iter(struct kiocb *kio, struct iov_iter *iov_iter)
++{
++	ssize_t err;
++	struct file *file, *h_file;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	file = kio->ki_filp;
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	h_file = au_hf_top(file);
++	get_file(h_file);
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++
++	err = au_do_iter(h_file, MAY_READ, kio, iov_iter);
++	/* todo: necessary? */
++	/* file->f_ra = h_file->f_ra; */
++	/* update without lock, I don't think it a problem */
++	fsstack_copy_attr_atime(dentry->d_inode, file_inode(h_file));
++	fput(h_file);
++
++out:
++	si_read_unlock(sb);
++	return err;
++}
++
++static ssize_t aufs_write_iter(struct kiocb *kio, struct iov_iter *iov_iter)
++{
++	ssize_t err;
++	blkcnt_t blks;
++	aufs_bindex_t bstart;
++	struct au_pin pin;
++	struct dentry *dentry;
++	struct inode *inode, *h_inode;
++	struct file *file, *h_file;
++	struct super_block *sb;
++
++	file = kio->ki_filp;
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	au_mtx_and_read_lock(inode);
++
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err)) {
++		di_read_unlock(dentry, AuLock_IR);
++		fi_write_unlock(file);
++		goto out;
++	}
++
++	bstart = au_fbstart(file);
++	h_file = au_hf_top(file);
++	get_file(h_file);
++	h_inode = file_inode(h_file);
++	blks = h_inode->i_blocks;
++	au_unpin(&pin);
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++
++	err = au_do_iter(h_file, MAY_WRITE, kio, iov_iter);
++	ii_write_lock_child(inode);
++	au_cpup_attr_timesizes(inode);
++	inode->i_mode = file_inode(h_file)->i_mode;
++	AuDbg("blks %llu, %llu\n", (u64)blks, (u64)h_inode->i_blocks);
++	if (err > 0)
++		au_fhsm_wrote(sb, bstart, /*force*/h_inode->i_blocks > blks);
++	ii_write_unlock(inode);
++	fput(h_file);
++
++out:
++	si_read_unlock(sb);
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
++
++static ssize_t aufs_splice_read(struct file *file, loff_t *ppos,
++				struct pipe_inode_info *pipe, size_t len,
++				unsigned int flags)
++{
++	ssize_t err;
++	struct file *h_file;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	err = -EINVAL;
++	h_file = au_hf_top(file);
++	get_file(h_file);
++	if (au_test_loopback_kthread()) {
++		au_warn_loopback(h_file->f_path.dentry->d_sb);
++		if (file->f_mapping != h_file->f_mapping) {
++			file->f_mapping = h_file->f_mapping;
++			smp_mb(); /* unnecessary? */
++		}
++	}
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++
++	err = vfsub_splice_to(h_file, ppos, pipe, len, flags);
++	/* todo: necessasry? */
++	/* file->f_ra = h_file->f_ra; */
++	/* update without lock, I don't think it a problem */
++	fsstack_copy_attr_atime(dentry->d_inode, file_inode(h_file));
++	fput(h_file);
++
++out:
++	si_read_unlock(sb);
++	return err;
++}
++
++static ssize_t
++aufs_splice_write(struct pipe_inode_info *pipe, struct file *file, loff_t *ppos,
++		  size_t len, unsigned int flags)
++{
++	ssize_t err;
++	blkcnt_t blks;
++	aufs_bindex_t bstart;
++	struct au_pin pin;
++	struct dentry *dentry;
++	struct inode *inode, *h_inode;
++	struct super_block *sb;
++	struct file *h_file;
++
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	au_mtx_and_read_lock(inode);
++
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err)) {
++		di_read_unlock(dentry, AuLock_IR);
++		fi_write_unlock(file);
++		goto out;
++	}
++
++	bstart = au_fbstart(file);
++	h_file = au_hf_top(file);
++	get_file(h_file);
++	h_inode = file_inode(h_file);
++	blks = h_inode->i_blocks;
++	au_unpin(&pin);
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++
++	err = vfsub_splice_from(pipe, h_file, ppos, len, flags);
++	ii_write_lock_child(inode);
++	au_cpup_attr_timesizes(inode);
++	inode->i_mode = file_inode(h_file)->i_mode;
++	AuDbg("blks %llu, %llu\n", (u64)blks, (u64)h_inode->i_blocks);
++	if (err > 0)
++		au_fhsm_wrote(sb, bstart, /*force*/h_inode->i_blocks > blks);
++	ii_write_unlock(inode);
++	fput(h_file);
++
++out:
++	si_read_unlock(sb);
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
++
++static long aufs_fallocate(struct file *file, int mode, loff_t offset,
++			   loff_t len)
++{
++	long err;
++	struct au_pin pin;
++	struct dentry *dentry;
++	struct super_block *sb;
++	struct inode *inode;
++	struct file *h_file;
++
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	inode = dentry->d_inode;
++	au_mtx_and_read_lock(inode);
++
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err)) {
++		di_read_unlock(dentry, AuLock_IR);
++		fi_write_unlock(file);
++		goto out;
++	}
++
++	h_file = au_hf_top(file);
++	get_file(h_file);
++	au_unpin(&pin);
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++
++	lockdep_off();
++	err = vfs_fallocate(h_file, mode, offset, len);
++	lockdep_on();
++	ii_write_lock_child(inode);
++	au_cpup_attr_timesizes(inode);
++	inode->i_mode = file_inode(h_file)->i_mode;
++	ii_write_unlock(inode);
++	fput(h_file);
++
++out:
++	si_read_unlock(sb);
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * The locking order around current->mmap_sem.
++ * - in most and regular cases
++ *   file I/O syscall -- aufs_read() or something
++ *	-- si_rwsem for read -- mmap_sem
++ *	(Note that [fdi]i_rwsem are released before mmap_sem).
++ * - in mmap case
++ *   mmap(2) -- mmap_sem -- aufs_mmap() -- si_rwsem for read -- [fdi]i_rwsem
++ * This AB-BA order is definitly bad, but is not a problem since "si_rwsem for
++ * read" allows muliple processes to acquire it and [fdi]i_rwsem are not held in
++ * file I/O. Aufs needs to stop lockdep in aufs_mmap() though.
++ * It means that when aufs acquires si_rwsem for write, the process should never
++ * acquire mmap_sem.
++ *
++ * Actually aufs_iterate() holds [fdi]i_rwsem before mmap_sem, but this is not a
++ * problem either since any directory is not able to be mmap-ed.
++ * The similar scenario is applied to aufs_readlink() too.
++ */
++
++#if 0 /* stop calling security_file_mmap() */
++/* cf. linux/include/linux/mman.h: calc_vm_prot_bits() */
++#define AuConv_VM_PROT(f, b)	_calc_vm_trans(f, VM_##b, PROT_##b)
++
++static unsigned long au_arch_prot_conv(unsigned long flags)
++{
++	/* currently ppc64 only */
++#ifdef CONFIG_PPC64
++	/* cf. linux/arch/powerpc/include/asm/mman.h */
++	AuDebugOn(arch_calc_vm_prot_bits(-1) != VM_SAO);
++	return AuConv_VM_PROT(flags, SAO);
++#else
++	AuDebugOn(arch_calc_vm_prot_bits(-1));
++	return 0;
++#endif
++}
++
++static unsigned long au_prot_conv(unsigned long flags)
++{
++	return AuConv_VM_PROT(flags, READ)
++		| AuConv_VM_PROT(flags, WRITE)
++		| AuConv_VM_PROT(flags, EXEC)
++		| au_arch_prot_conv(flags);
++}
++
++/* cf. linux/include/linux/mman.h: calc_vm_flag_bits() */
++#define AuConv_VM_MAP(f, b)	_calc_vm_trans(f, VM_##b, MAP_##b)
++
++static unsigned long au_flag_conv(unsigned long flags)
++{
++	return AuConv_VM_MAP(flags, GROWSDOWN)
++		| AuConv_VM_MAP(flags, DENYWRITE)
++		| AuConv_VM_MAP(flags, LOCKED);
++}
++#endif
++
++static int aufs_mmap(struct file *file, struct vm_area_struct *vma)
++{
++	int err;
++	aufs_bindex_t bstart;
++	const unsigned char wlock
++		= (file->f_mode & FMODE_WRITE) && (vma->vm_flags & VM_SHARED);
++	struct dentry *dentry;
++	struct super_block *sb;
++	struct file *h_file;
++	struct au_branch *br;
++	struct au_pin pin;
++
++	AuDbgVmRegion(file, vma);
++
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	lockdep_off();
++	si_read_lock(sb, AuLock_NOPLMW);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	if (wlock) {
++		err = au_ready_to_write(file, -1, &pin);
++		di_write_unlock(dentry);
++		if (unlikely(err)) {
++			fi_write_unlock(file);
++			goto out;
++		}
++		au_unpin(&pin);
++	} else
++		di_write_unlock(dentry);
++
++	bstart = au_fbstart(file);
++	br = au_sbr(sb, bstart);
++	h_file = au_hf_top(file);
++	get_file(h_file);
++	au_set_mmapped(file);
++	fi_write_unlock(file);
++	lockdep_on();
++
++	au_vm_file_reset(vma, h_file);
++	/*
++	 * we cannot call security_mmap_file() here since it may acquire
++	 * mmap_sem or i_mutex.
++	 *
++	 * err = security_mmap_file(h_file, au_prot_conv(vma->vm_flags),
++	 *			 au_flag_conv(vma->vm_flags));
++	 */
++	if (!err)
++		err = h_file->f_op->mmap(h_file, vma);
++	if (unlikely(err))
++		goto out_reset;
++
++	au_vm_prfile_set(vma, file);
++	/* update without lock, I don't think it a problem */
++	fsstack_copy_attr_atime(file_inode(file), file_inode(h_file));
++	goto out_fput; /* success */
++
++out_reset:
++	au_unset_mmapped(file);
++	au_vm_file_reset(vma, file);
++out_fput:
++	fput(h_file);
++	lockdep_off();
++out:
++	si_read_unlock(sb);
++	lockdep_on();
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int aufs_fsync_nondir(struct file *file, loff_t start, loff_t end,
++			     int datasync)
++{
++	int err;
++	struct au_pin pin;
++	struct dentry *dentry;
++	struct inode *inode;
++	struct file *h_file;
++	struct super_block *sb;
++
++	dentry = file->f_path.dentry;
++	inode = dentry->d_inode;
++	sb = dentry->d_sb;
++	mutex_lock(&inode->i_mutex);
++	err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++	if (unlikely(err))
++		goto out;
++
++	err = 0; /* -EBADF; */ /* posix? */
++	if (unlikely(!(file->f_mode & FMODE_WRITE)))
++		goto out_si;
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out_si;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err))
++		goto out_unlock;
++	au_unpin(&pin);
++
++	err = -EINVAL;
++	h_file = au_hf_top(file);
++	err = vfsub_fsync(h_file, &h_file->f_path, datasync);
++	au_cpup_attr_timesizes(inode);
++
++out_unlock:
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++out_si:
++	si_read_unlock(sb);
++out:
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
++
++/* no one supports this operation, currently */
++#if 0
++static int aufs_aio_fsync_nondir(struct kiocb *kio, int datasync)
++{
++	int err;
++	struct au_pin pin;
++	struct dentry *dentry;
++	struct inode *inode;
++	struct file *file, *h_file;
++
++	file = kio->ki_filp;
++	dentry = file->f_path.dentry;
++	inode = dentry->d_inode;
++	au_mtx_and_read_lock(inode);
++
++	err = 0; /* -EBADF; */ /* posix? */
++	if (unlikely(!(file->f_mode & FMODE_WRITE)))
++		goto out;
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++	if (unlikely(err))
++		goto out;
++
++	err = au_ready_to_write(file, -1, &pin);
++	di_downgrade_lock(dentry, AuLock_IR);
++	if (unlikely(err))
++		goto out_unlock;
++	au_unpin(&pin);
++
++	err = -ENOSYS;
++	h_file = au_hf_top(file);
++	if (h_file->f_op->aio_fsync) {
++		struct mutex *h_mtx;
++
++		h_mtx = &file_inode(h_file)->i_mutex;
++		if (!is_sync_kiocb(kio)) {
++			get_file(h_file);
++			fput(file);
++		}
++		kio->ki_filp = h_file;
++		err = h_file->f_op->aio_fsync(kio, datasync);
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		if (!err)
++			vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL);
++		/*ignore*/
++		au_cpup_attr_timesizes(inode);
++		mutex_unlock(h_mtx);
++	}
++
++out_unlock:
++	di_read_unlock(dentry, AuLock_IR);
++	fi_write_unlock(file);
++out:
++	si_read_unlock(inode->sb);
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
++#endif
++
++static int aufs_fasync(int fd, struct file *file, int flag)
++{
++	int err;
++	struct file *h_file;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	h_file = au_hf_top(file);
++	if (h_file->f_op->fasync)
++		err = h_file->f_op->fasync(fd, h_file, flag);
++
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++
++out:
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* no one supports this operation, currently */
++#if 0
++static ssize_t aufs_sendpage(struct file *file, struct page *page, int offset,
++			     size_t len, loff_t *pos, int more)
++{
++}
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++const struct file_operations aufs_file_fop = {
++	.owner		= THIS_MODULE,
++
++	.llseek		= default_llseek,
++
++	.read		= aufs_read,
++	.write		= aufs_write,
++	.read_iter	= aufs_read_iter,
++	.write_iter	= aufs_write_iter,
++
++#ifdef CONFIG_AUFS_POLL
++	.poll		= aufs_poll,
++#endif
++	.unlocked_ioctl	= aufs_ioctl_nondir,
++#ifdef CONFIG_COMPAT
++	.compat_ioctl	= aufs_compat_ioctl_nondir,
++#endif
++	.mmap		= aufs_mmap,
++	.open		= aufs_open_nondir,
++	.flush		= aufs_flush_nondir,
++	.release	= aufs_release_nondir,
++	.fsync		= aufs_fsync_nondir,
++	/* .aio_fsync	= aufs_aio_fsync_nondir, */
++	.fasync		= aufs_fasync,
++	/* .sendpage	= aufs_sendpage, */
++	.splice_write	= aufs_splice_write,
++	.splice_read	= aufs_splice_read,
++#if 0
++	.aio_splice_write = aufs_aio_splice_write,
++	.aio_splice_read  = aufs_aio_splice_read,
++#endif
++	.fallocate	= aufs_fallocate
++};
+diff -Nur linux-4.0.4.orig/fs/aufs/fstype.h linux-4.0.4/fs/aufs/fstype.h
+--- linux-4.0.4.orig/fs/aufs/fstype.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/fstype.h	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,387 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * judging filesystem type
++ */
++
++#ifndef __AUFS_FSTYPE_H__
++#define __AUFS_FSTYPE_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/magic.h>
++#include <linux/romfs_fs.h>
++#include <linux/nfs_fs.h>
++
++static inline int au_test_aufs(struct super_block *sb)
++{
++	return sb->s_magic == AUFS_SUPER_MAGIC;
++}
++
++static inline const char *au_sbtype(struct super_block *sb)
++{
++	return sb->s_type->name;
++}
++
++static inline int au_test_iso9660(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_ISO9660_FS) || defined(CONFIG_ISO9660_FS_MODULE)
++	return sb->s_magic == ISOFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_romfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_ROMFS_FS) || defined(CONFIG_ROMFS_FS_MODULE)
++	return sb->s_magic == ROMFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_cramfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_CRAMFS) || defined(CONFIG_CRAMFS_MODULE)
++	return sb->s_magic == CRAMFS_MAGIC;
++#endif
++	return 0;
++}
++
++static inline int au_test_nfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_NFS_FS) || defined(CONFIG_NFS_FS_MODULE)
++	return sb->s_magic == NFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_fuse(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_FUSE_FS) || defined(CONFIG_FUSE_FS_MODULE)
++	return sb->s_magic == FUSE_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_xfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_XFS_FS) || defined(CONFIG_XFS_FS_MODULE)
++	return sb->s_magic == XFS_SB_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_tmpfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_TMPFS
++	return sb->s_magic == TMPFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_ecryptfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_ECRYPT_FS) || defined(CONFIG_ECRYPT_FS_MODULE)
++	return !strcmp(au_sbtype(sb), "ecryptfs");
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_ramfs(struct super_block *sb)
++{
++	return sb->s_magic == RAMFS_MAGIC;
++}
++
++static inline int au_test_ubifs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_UBIFS_FS) || defined(CONFIG_UBIFS_FS_MODULE)
++	return sb->s_magic == UBIFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_procfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_PROC_FS
++	return sb->s_magic == PROC_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_sysfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_SYSFS
++	return sb->s_magic == SYSFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_configfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_CONFIGFS_FS) || defined(CONFIG_CONFIGFS_FS_MODULE)
++	return sb->s_magic == CONFIGFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_minix(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_MINIX_FS) || defined(CONFIG_MINIX_FS_MODULE)
++	return sb->s_magic == MINIX3_SUPER_MAGIC
++		|| sb->s_magic == MINIX2_SUPER_MAGIC
++		|| sb->s_magic == MINIX2_SUPER_MAGIC2
++		|| sb->s_magic == MINIX_SUPER_MAGIC
++		|| sb->s_magic == MINIX_SUPER_MAGIC2;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_fat(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_FAT_FS) || defined(CONFIG_FAT_FS_MODULE)
++	return sb->s_magic == MSDOS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_msdos(struct super_block *sb)
++{
++	return au_test_fat(sb);
++}
++
++static inline int au_test_vfat(struct super_block *sb)
++{
++	return au_test_fat(sb);
++}
++
++static inline int au_test_securityfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_SECURITYFS
++	return sb->s_magic == SECURITYFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_squashfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_SQUASHFS) || defined(CONFIG_SQUASHFS_MODULE)
++	return sb->s_magic == SQUASHFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_btrfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_BTRFS_FS) || defined(CONFIG_BTRFS_FS_MODULE)
++	return sb->s_magic == BTRFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_xenfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_XENFS) || defined(CONFIG_XENFS_MODULE)
++	return sb->s_magic == XENFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_debugfs(struct super_block *sb __maybe_unused)
++{
++#ifdef CONFIG_DEBUG_FS
++	return sb->s_magic == DEBUGFS_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_nilfs(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_NILFS) || defined(CONFIG_NILFS_MODULE)
++	return sb->s_magic == NILFS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++static inline int au_test_hfsplus(struct super_block *sb __maybe_unused)
++{
++#if defined(CONFIG_HFSPLUS_FS) || defined(CONFIG_HFSPLUS_FS_MODULE)
++	return sb->s_magic == HFSPLUS_SUPER_MAGIC;
++#else
++	return 0;
++#endif
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * they can't be an aufs branch.
++ */
++static inline int au_test_fs_unsuppoted(struct super_block *sb)
++{
++	return
++#ifndef CONFIG_AUFS_BR_RAMFS
++		au_test_ramfs(sb) ||
++#endif
++		au_test_procfs(sb)
++		|| au_test_sysfs(sb)
++		|| au_test_configfs(sb)
++		|| au_test_debugfs(sb)
++		|| au_test_securityfs(sb)
++		|| au_test_xenfs(sb)
++		|| au_test_ecryptfs(sb)
++		/* || !strcmp(au_sbtype(sb), "unionfs") */
++		|| au_test_aufs(sb); /* will be supported in next version */
++}
++
++static inline int au_test_fs_remote(struct super_block *sb)
++{
++	return !au_test_tmpfs(sb)
++#ifdef CONFIG_AUFS_BR_RAMFS
++		&& !au_test_ramfs(sb)
++#endif
++		&& !(sb->s_type->fs_flags & FS_REQUIRES_DEV);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * Note: these functions (below) are created after reading ->getattr() in all
++ * filesystems under linux/fs. it means we have to do so in every update...
++ */
++
++/*
++ * some filesystems require getattr to refresh the inode attributes before
++ * referencing.
++ * in most cases, we can rely on the inode attribute in NFS (or every remote fs)
++ * and leave the work for d_revalidate()
++ */
++static inline int au_test_fs_refresh_iattr(struct super_block *sb)
++{
++	return au_test_nfs(sb)
++		|| au_test_fuse(sb)
++		/* || au_test_btrfs(sb) */	/* untested */
++		;
++}
++
++/*
++ * filesystems which don't maintain i_size or i_blocks.
++ */
++static inline int au_test_fs_bad_iattr_size(struct super_block *sb)
++{
++	return au_test_xfs(sb)
++		|| au_test_btrfs(sb)
++		|| au_test_ubifs(sb)
++		|| au_test_hfsplus(sb)	/* maintained, but incorrect */
++		/* || au_test_minix(sb) */	/* untested */
++		;
++}
++
++/*
++ * filesystems which don't store the correct value in some of their inode
++ * attributes.
++ */
++static inline int au_test_fs_bad_iattr(struct super_block *sb)
++{
++	return au_test_fs_bad_iattr_size(sb)
++		|| au_test_fat(sb)
++		|| au_test_msdos(sb)
++		|| au_test_vfat(sb);
++}
++
++/* they don't check i_nlink in link(2) */
++static inline int au_test_fs_no_limit_nlink(struct super_block *sb)
++{
++	return au_test_tmpfs(sb)
++#ifdef CONFIG_AUFS_BR_RAMFS
++		|| au_test_ramfs(sb)
++#endif
++		|| au_test_ubifs(sb)
++		|| au_test_hfsplus(sb);
++}
++
++/*
++ * filesystems which sets S_NOATIME and S_NOCMTIME.
++ */
++static inline int au_test_fs_notime(struct super_block *sb)
++{
++	return au_test_nfs(sb)
++		|| au_test_fuse(sb)
++		|| au_test_ubifs(sb)
++		;
++}
++
++/* temporary support for i#1 in cramfs */
++static inline int au_test_fs_unique_ino(struct inode *inode)
++{
++	if (au_test_cramfs(inode->i_sb))
++		return inode->i_ino != 1;
++	return 1;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * the filesystem where the xino files placed must support i/o after unlink and
++ * maintain i_size and i_blocks.
++ */
++static inline int au_test_fs_bad_xino(struct super_block *sb)
++{
++	return au_test_fs_remote(sb)
++		|| au_test_fs_bad_iattr_size(sb)
++		/* don't want unnecessary work for xino */
++		|| au_test_aufs(sb)
++		|| au_test_ecryptfs(sb)
++		|| au_test_nilfs(sb);
++}
++
++static inline int au_test_fs_trunc_xino(struct super_block *sb)
++{
++	return au_test_tmpfs(sb)
++		|| au_test_ramfs(sb);
++}
++
++/*
++ * test if the @sb is real-readonly.
++ */
++static inline int au_test_fs_rr(struct super_block *sb)
++{
++	return au_test_squashfs(sb)
++		|| au_test_iso9660(sb)
++		|| au_test_cramfs(sb)
++		|| au_test_romfs(sb);
++}
++
++/*
++ * test if the @inode is nfs with 'noacl' option
++ * NFS always sets MS_POSIXACL regardless its mount option 'noacl.'
++ */
++static inline int au_test_nfs_noacl(struct inode *inode)
++{
++	return au_test_nfs(inode->i_sb)
++		/* && IS_POSIXACL(inode) */
++		&& !nfs_server_capable(inode, NFS_CAP_ACLS);
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_FSTYPE_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/hfsnotify.c linux-4.0.4/fs/aufs/hfsnotify.c
+--- linux-4.0.4.orig/fs/aufs/hfsnotify.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/hfsnotify.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,275 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * fsnotify for the lower directories
++ */
++
++#include "aufs.h"
++
++/* FS_IN_IGNORED is unnecessary */
++static const __u32 AuHfsnMask = (FS_MOVED_TO | FS_MOVED_FROM | FS_DELETE
++				 | FS_CREATE | FS_EVENT_ON_CHILD);
++static DECLARE_WAIT_QUEUE_HEAD(au_hfsn_wq);
++static __cacheline_aligned_in_smp atomic64_t au_hfsn_ifree = ATOMIC64_INIT(0);
++
++static void au_hfsn_free_mark(struct fsnotify_mark *mark)
++{
++	struct au_hnotify *hn = container_of(mark, struct au_hnotify,
++					     hn_mark);
++	AuDbg("here\n");
++	au_cache_free_hnotify(hn);
++	smp_mb__before_atomic();
++	if (atomic64_dec_and_test(&au_hfsn_ifree))
++		wake_up(&au_hfsn_wq);
++}
++
++static int au_hfsn_alloc(struct au_hinode *hinode)
++{
++	int err;
++	struct au_hnotify *hn;
++	struct super_block *sb;
++	struct au_branch *br;
++	struct fsnotify_mark *mark;
++	aufs_bindex_t bindex;
++
++	hn = hinode->hi_notify;
++	sb = hn->hn_aufs_inode->i_sb;
++	bindex = au_br_index(sb, hinode->hi_id);
++	br = au_sbr(sb, bindex);
++	AuDebugOn(!br->br_hfsn);
++
++	mark = &hn->hn_mark;
++	fsnotify_init_mark(mark, au_hfsn_free_mark);
++	mark->mask = AuHfsnMask;
++	/*
++	 * by udba rename or rmdir, aufs assign a new inode to the known
++	 * h_inode, so specify 1 to allow dups.
++	 */
++	lockdep_off();
++	err = fsnotify_add_mark(mark, br->br_hfsn->hfsn_group, hinode->hi_inode,
++				 /*mnt*/NULL, /*allow_dups*/1);
++	/* even if err */
++	fsnotify_put_mark(mark);
++	lockdep_on();
++
++	return err;
++}
++
++static int au_hfsn_free(struct au_hinode *hinode, struct au_hnotify *hn)
++{
++	struct fsnotify_mark *mark;
++	unsigned long long ull;
++	struct fsnotify_group *group;
++
++	ull = atomic64_inc_return(&au_hfsn_ifree);
++	BUG_ON(!ull);
++
++	mark = &hn->hn_mark;
++	spin_lock(&mark->lock);
++	group = mark->group;
++	fsnotify_get_group(group);
++	spin_unlock(&mark->lock);
++	lockdep_off();
++	fsnotify_destroy_mark(mark, group);
++	fsnotify_put_group(group);
++	lockdep_on();
++
++	/* free hn by myself */
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void au_hfsn_ctl(struct au_hinode *hinode, int do_set)
++{
++	struct fsnotify_mark *mark;
++
++	mark = &hinode->hi_notify->hn_mark;
++	spin_lock(&mark->lock);
++	if (do_set) {
++		AuDebugOn(mark->mask & AuHfsnMask);
++		mark->mask |= AuHfsnMask;
++	} else {
++		AuDebugOn(!(mark->mask & AuHfsnMask));
++		mark->mask &= ~AuHfsnMask;
++	}
++	spin_unlock(&mark->lock);
++	/* fsnotify_recalc_inode_mask(hinode->hi_inode); */
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* #define AuDbgHnotify */
++#ifdef AuDbgHnotify
++static char *au_hfsn_name(u32 mask)
++{
++#ifdef CONFIG_AUFS_DEBUG
++#define test_ret(flag)				\
++	do {					\
++		if (mask & flag)		\
++			return #flag;		\
++	} while (0)
++	test_ret(FS_ACCESS);
++	test_ret(FS_MODIFY);
++	test_ret(FS_ATTRIB);
++	test_ret(FS_CLOSE_WRITE);
++	test_ret(FS_CLOSE_NOWRITE);
++	test_ret(FS_OPEN);
++	test_ret(FS_MOVED_FROM);
++	test_ret(FS_MOVED_TO);
++	test_ret(FS_CREATE);
++	test_ret(FS_DELETE);
++	test_ret(FS_DELETE_SELF);
++	test_ret(FS_MOVE_SELF);
++	test_ret(FS_UNMOUNT);
++	test_ret(FS_Q_OVERFLOW);
++	test_ret(FS_IN_IGNORED);
++	test_ret(FS_ISDIR);
++	test_ret(FS_IN_ONESHOT);
++	test_ret(FS_EVENT_ON_CHILD);
++	return "";
++#undef test_ret
++#else
++	return "??";
++#endif
++}
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++static void au_hfsn_free_group(struct fsnotify_group *group)
++{
++	struct au_br_hfsnotify *hfsn = group->private;
++
++	AuDbg("here\n");
++	kfree(hfsn);
++}
++
++static int au_hfsn_handle_event(struct fsnotify_group *group,
++				struct inode *inode,
++				struct fsnotify_mark *inode_mark,
++				struct fsnotify_mark *vfsmount_mark,
++				u32 mask, void *data, int data_type,
++				const unsigned char *file_name, u32 cookie)
++{
++	int err;
++	struct au_hnotify *hnotify;
++	struct inode *h_dir, *h_inode;
++	struct qstr h_child_qstr = QSTR_INIT(file_name, strlen(file_name));
++
++	AuDebugOn(data_type != FSNOTIFY_EVENT_INODE);
++
++	err = 0;
++	/* if FS_UNMOUNT happens, there must be another bug */
++	AuDebugOn(mask & FS_UNMOUNT);
++	if (mask & (FS_IN_IGNORED | FS_UNMOUNT))
++		goto out;
++
++	h_dir = inode;
++	h_inode = NULL;
++#ifdef AuDbgHnotify
++	au_debug_on();
++	if (1 || h_child_qstr.len != sizeof(AUFS_XINO_FNAME) - 1
++	    || strncmp(h_child_qstr.name, AUFS_XINO_FNAME, h_child_qstr.len)) {
++		AuDbg("i%lu, mask 0x%x %s, hcname %.*s, hi%lu\n",
++		      h_dir->i_ino, mask, au_hfsn_name(mask),
++		      AuLNPair(&h_child_qstr), h_inode ? h_inode->i_ino : 0);
++		/* WARN_ON(1); */
++	}
++	au_debug_off();
++#endif
++
++	AuDebugOn(!inode_mark);
++	hnotify = container_of(inode_mark, struct au_hnotify, hn_mark);
++	err = au_hnotify(h_dir, hnotify, mask, &h_child_qstr, h_inode);
++
++out:
++	return err;
++}
++
++static struct fsnotify_ops au_hfsn_ops = {
++	.handle_event		= au_hfsn_handle_event,
++	.free_group_priv	= au_hfsn_free_group
++};
++
++/* ---------------------------------------------------------------------- */
++
++static void au_hfsn_fin_br(struct au_branch *br)
++{
++	struct au_br_hfsnotify *hfsn;
++
++	hfsn = br->br_hfsn;
++	if (hfsn) {
++		lockdep_off();
++		fsnotify_put_group(hfsn->hfsn_group);
++		lockdep_on();
++	}
++}
++
++static int au_hfsn_init_br(struct au_branch *br, int perm)
++{
++	int err;
++	struct fsnotify_group *group;
++	struct au_br_hfsnotify *hfsn;
++
++	err = 0;
++	br->br_hfsn = NULL;
++	if (!au_br_hnotifyable(perm))
++		goto out;
++
++	err = -ENOMEM;
++	hfsn = kmalloc(sizeof(*hfsn), GFP_NOFS);
++	if (unlikely(!hfsn))
++		goto out;
++
++	err = 0;
++	group = fsnotify_alloc_group(&au_hfsn_ops);
++	if (IS_ERR(group)) {
++		err = PTR_ERR(group);
++		pr_err("fsnotify_alloc_group() failed, %d\n", err);
++		goto out_hfsn;
++	}
++
++	group->private = hfsn;
++	hfsn->hfsn_group = group;
++	br->br_hfsn = hfsn;
++	goto out; /* success */
++
++out_hfsn:
++	kfree(hfsn);
++out:
++	return err;
++}
++
++static int au_hfsn_reset_br(unsigned int udba, struct au_branch *br, int perm)
++{
++	int err;
++
++	err = 0;
++	if (!br->br_hfsn)
++		err = au_hfsn_init_br(br, perm);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void au_hfsn_fin(void)
++{
++	AuDbg("au_hfsn_ifree %lld\n", (long long)atomic64_read(&au_hfsn_ifree));
++	wait_event(au_hfsn_wq, !atomic64_read(&au_hfsn_ifree));
++}
++
++const struct au_hnotify_op au_hnotify_op = {
++	.ctl		= au_hfsn_ctl,
++	.alloc		= au_hfsn_alloc,
++	.free		= au_hfsn_free,
++
++	.fin		= au_hfsn_fin,
++
++	.reset_br	= au_hfsn_reset_br,
++	.fin_br		= au_hfsn_fin_br,
++	.init_br	= au_hfsn_init_br
++};
+diff -Nur linux-4.0.4.orig/fs/aufs/hfsplus.c linux-4.0.4/fs/aufs/hfsplus.c
+--- linux-4.0.4.orig/fs/aufs/hfsplus.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/hfsplus.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,43 @@
++/*
++ * Copyright (C) 2010-2015 Junjiro R. Okajima
++ */
++
++/*
++ * special support for filesystems which aqucires an inode mutex
++ * at final closing a file, eg, hfsplus.
++ *
++ * This trick is very simple and stupid, just to open the file before really
++ * neceeary open to tell hfsplus that this is not the final closing.
++ * The caller should call au_h_open_pre() after acquiring the inode mutex,
++ * and au_h_open_post() after releasing it.
++ */
++
++#include "aufs.h"
++
++struct file *au_h_open_pre(struct dentry *dentry, aufs_bindex_t bindex,
++			   int force_wr)
++{
++	struct file *h_file;
++	struct dentry *h_dentry;
++
++	h_dentry = au_h_dptr(dentry, bindex);
++	AuDebugOn(!h_dentry);
++	AuDebugOn(!h_dentry->d_inode);
++
++	h_file = NULL;
++	if (au_test_hfsplus(h_dentry->d_sb)
++	    && d_is_reg(h_dentry))
++		h_file = au_h_open(dentry, bindex,
++				   O_RDONLY | O_NOATIME | O_LARGEFILE,
++				   /*file*/NULL, force_wr);
++	return h_file;
++}
++
++void au_h_open_post(struct dentry *dentry, aufs_bindex_t bindex,
++		    struct file *h_file)
++{
++	if (h_file) {
++		fput(h_file);
++		au_sbr_put(dentry->d_sb, bindex);
++	}
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/hnotify.c linux-4.0.4/fs/aufs/hnotify.c
+--- linux-4.0.4.orig/fs/aufs/hnotify.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/hnotify.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,701 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * abstraction to notify the direct changes on lower directories
++ */
++
++#include "aufs.h"
++
++int au_hn_alloc(struct au_hinode *hinode, struct inode *inode)
++{
++	int err;
++	struct au_hnotify *hn;
++
++	err = -ENOMEM;
++	hn = au_cache_alloc_hnotify();
++	if (hn) {
++		hn->hn_aufs_inode = inode;
++		hinode->hi_notify = hn;
++		err = au_hnotify_op.alloc(hinode);
++		AuTraceErr(err);
++		if (unlikely(err)) {
++			hinode->hi_notify = NULL;
++			au_cache_free_hnotify(hn);
++			/*
++			 * The upper dir was removed by udba, but the same named
++			 * dir left. In this case, aufs assignes a new inode
++			 * number and set the monitor again.
++			 * For the lower dir, the old monitnor is still left.
++			 */
++			if (err == -EEXIST)
++				err = 0;
++		}
++	}
++
++	AuTraceErr(err);
++	return err;
++}
++
++void au_hn_free(struct au_hinode *hinode)
++{
++	struct au_hnotify *hn;
++
++	hn = hinode->hi_notify;
++	if (hn) {
++		hinode->hi_notify = NULL;
++		if (au_hnotify_op.free(hinode, hn))
++			au_cache_free_hnotify(hn);
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_hn_ctl(struct au_hinode *hinode, int do_set)
++{
++	if (hinode->hi_notify)
++		au_hnotify_op.ctl(hinode, do_set);
++}
++
++void au_hn_reset(struct inode *inode, unsigned int flags)
++{
++	aufs_bindex_t bindex, bend;
++	struct inode *hi;
++	struct dentry *iwhdentry;
++
++	bend = au_ibend(inode);
++	for (bindex = au_ibstart(inode); bindex <= bend; bindex++) {
++		hi = au_h_iptr(inode, bindex);
++		if (!hi)
++			continue;
++
++		/* mutex_lock_nested(&hi->i_mutex, AuLsc_I_CHILD); */
++		iwhdentry = au_hi_wh(inode, bindex);
++		if (iwhdentry)
++			dget(iwhdentry);
++		au_igrab(hi);
++		au_set_h_iptr(inode, bindex, NULL, 0);
++		au_set_h_iptr(inode, bindex, au_igrab(hi),
++			      flags & ~AuHi_XINO);
++		iput(hi);
++		dput(iwhdentry);
++		/* mutex_unlock(&hi->i_mutex); */
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int hn_xino(struct inode *inode, struct inode *h_inode)
++{
++	int err;
++	aufs_bindex_t bindex, bend, bfound, bstart;
++	struct inode *h_i;
++
++	err = 0;
++	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
++		pr_warn("branch root dir was changed\n");
++		goto out;
++	}
++
++	bfound = -1;
++	bend = au_ibend(inode);
++	bstart = au_ibstart(inode);
++#if 0 /* reserved for future use */
++	if (bindex == bend) {
++		/* keep this ino in rename case */
++		goto out;
++	}
++#endif
++	for (bindex = bstart; bindex <= bend; bindex++)
++		if (au_h_iptr(inode, bindex) == h_inode) {
++			bfound = bindex;
++			break;
++		}
++	if (bfound < 0)
++		goto out;
++
++	for (bindex = bstart; bindex <= bend; bindex++) {
++		h_i = au_h_iptr(inode, bindex);
++		if (!h_i)
++			continue;
++
++		err = au_xino_write(inode->i_sb, bindex, h_i->i_ino, /*ino*/0);
++		/* ignore this error */
++		/* bad action? */
++	}
++
++	/* children inode number will be broken */
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int hn_gen_tree(struct dentry *dentry)
++{
++	int err, i, j, ndentry;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry **dentries;
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	err = au_dcsub_pages(&dpages, dentry, NULL, NULL);
++	if (unlikely(err))
++		goto out_dpages;
++
++	for (i = 0; i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		ndentry = dpage->ndentry;
++		for (j = 0; j < ndentry; j++) {
++			struct dentry *d;
++
++			d = dentries[j];
++			if (IS_ROOT(d))
++				continue;
++
++			au_digen_dec(d);
++			if (d->d_inode)
++				/* todo: reset children xino?
++				   cached children only? */
++				au_iigen_dec(d->d_inode);
++		}
++	}
++
++out_dpages:
++	au_dpages_free(&dpages);
++
++#if 0
++	/* discard children */
++	dentry_unhash(dentry);
++	dput(dentry);
++#endif
++out:
++	return err;
++}
++
++/*
++ * return 0 if processed.
++ */
++static int hn_gen_by_inode(char *name, unsigned int nlen, struct inode *inode,
++			   const unsigned int isdir)
++{
++	int err;
++	struct dentry *d;
++	struct qstr *dname;
++
++	err = 1;
++	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
++		pr_warn("branch root dir was changed\n");
++		err = 0;
++		goto out;
++	}
++
++	if (!isdir) {
++		AuDebugOn(!name);
++		au_iigen_dec(inode);
++		spin_lock(&inode->i_lock);
++		hlist_for_each_entry(d, &inode->i_dentry, d_u.d_alias) {
++			spin_lock(&d->d_lock);
++			dname = &d->d_name;
++			if (dname->len != nlen
++			    && memcmp(dname->name, name, nlen)) {
++				spin_unlock(&d->d_lock);
++				continue;
++			}
++			err = 0;
++			au_digen_dec(d);
++			spin_unlock(&d->d_lock);
++			break;
++		}
++		spin_unlock(&inode->i_lock);
++	} else {
++		au_fset_si(au_sbi(inode->i_sb), FAILED_REFRESH_DIR);
++		d = d_find_any_alias(inode);
++		if (!d) {
++			au_iigen_dec(inode);
++			goto out;
++		}
++
++		spin_lock(&d->d_lock);
++		dname = &d->d_name;
++		if (dname->len == nlen && !memcmp(dname->name, name, nlen)) {
++			spin_unlock(&d->d_lock);
++			err = hn_gen_tree(d);
++			spin_lock(&d->d_lock);
++		}
++		spin_unlock(&d->d_lock);
++		dput(d);
++	}
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int hn_gen_by_name(struct dentry *dentry, const unsigned int isdir)
++{
++	int err;
++	struct inode *inode;
++
++	inode = dentry->d_inode;
++	if (IS_ROOT(dentry)
++	    /* || (inode && inode->i_ino == AUFS_ROOT_INO) */
++		) {
++		pr_warn("branch root dir was changed\n");
++		return 0;
++	}
++
++	err = 0;
++	if (!isdir) {
++		au_digen_dec(dentry);
++		if (inode)
++			au_iigen_dec(inode);
++	} else {
++		au_fset_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIR);
++		if (inode)
++			err = hn_gen_tree(dentry);
++	}
++
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* hnotify job flags */
++#define AuHnJob_XINO0		1
++#define AuHnJob_GEN		(1 << 1)
++#define AuHnJob_DIRENT		(1 << 2)
++#define AuHnJob_ISDIR		(1 << 3)
++#define AuHnJob_TRYXINO0	(1 << 4)
++#define AuHnJob_MNTPNT		(1 << 5)
++#define au_ftest_hnjob(flags, name)	((flags) & AuHnJob_##name)
++#define au_fset_hnjob(flags, name) \
++	do { (flags) |= AuHnJob_##name; } while (0)
++#define au_fclr_hnjob(flags, name) \
++	do { (flags) &= ~AuHnJob_##name; } while (0)
++
++enum {
++	AuHn_CHILD,
++	AuHn_PARENT,
++	AuHnLast
++};
++
++struct au_hnotify_args {
++	struct inode *h_dir, *dir, *h_child_inode;
++	u32 mask;
++	unsigned int flags[AuHnLast];
++	unsigned int h_child_nlen;
++	char h_child_name[];
++};
++
++struct hn_job_args {
++	unsigned int flags;
++	struct inode *inode, *h_inode, *dir, *h_dir;
++	struct dentry *dentry;
++	char *h_name;
++	int h_nlen;
++};
++
++static int hn_job(struct hn_job_args *a)
++{
++	const unsigned int isdir = au_ftest_hnjob(a->flags, ISDIR);
++	int e;
++
++	/* reset xino */
++	if (au_ftest_hnjob(a->flags, XINO0) && a->inode)
++		hn_xino(a->inode, a->h_inode); /* ignore this error */
++
++	if (au_ftest_hnjob(a->flags, TRYXINO0)
++	    && a->inode
++	    && a->h_inode) {
++		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
++		if (!a->h_inode->i_nlink
++		    && !(a->h_inode->i_state & I_LINKABLE))
++			hn_xino(a->inode, a->h_inode); /* ignore this error */
++		mutex_unlock(&a->h_inode->i_mutex);
++	}
++
++	/* make the generation obsolete */
++	if (au_ftest_hnjob(a->flags, GEN)) {
++		e = -1;
++		if (a->inode)
++			e = hn_gen_by_inode(a->h_name, a->h_nlen, a->inode,
++					      isdir);
++		if (e && a->dentry)
++			hn_gen_by_name(a->dentry, isdir);
++		/* ignore this error */
++	}
++
++	/* make dir entries obsolete */
++	if (au_ftest_hnjob(a->flags, DIRENT) && a->inode) {
++		struct au_vdir *vdir;
++
++		vdir = au_ivdir(a->inode);
++		if (vdir)
++			vdir->vd_jiffy = 0;
++		/* IMustLock(a->inode); */
++		/* a->inode->i_version++; */
++	}
++
++	/* can do nothing but warn */
++	if (au_ftest_hnjob(a->flags, MNTPNT)
++	    && a->dentry
++	    && d_mountpoint(a->dentry))
++		pr_warn("mount-point %pd is removed or renamed\n", a->dentry);
++
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct dentry *lookup_wlock_by_name(char *name, unsigned int nlen,
++					   struct inode *dir)
++{
++	struct dentry *dentry, *d, *parent;
++	struct qstr *dname;
++
++	parent = d_find_any_alias(dir);
++	if (!parent)
++		return NULL;
++
++	dentry = NULL;
++	spin_lock(&parent->d_lock);
++	list_for_each_entry(d, &parent->d_subdirs, d_child) {
++		/* AuDbg("%pd\n", d); */
++		spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
++		dname = &d->d_name;
++		if (dname->len != nlen || memcmp(dname->name, name, nlen))
++			goto cont_unlock;
++		if (au_di(d))
++			au_digen_dec(d);
++		else
++			goto cont_unlock;
++		if (au_dcount(d) > 0) {
++			dentry = dget_dlock(d);
++			spin_unlock(&d->d_lock);
++			break;
++		}
++
++cont_unlock:
++		spin_unlock(&d->d_lock);
++	}
++	spin_unlock(&parent->d_lock);
++	dput(parent);
++
++	if (dentry)
++		di_write_lock_child(dentry);
++
++	return dentry;
++}
++
++static struct inode *lookup_wlock_by_ino(struct super_block *sb,
++					 aufs_bindex_t bindex, ino_t h_ino)
++{
++	struct inode *inode;
++	ino_t ino;
++	int err;
++
++	inode = NULL;
++	err = au_xino_read(sb, bindex, h_ino, &ino);
++	if (!err && ino)
++		inode = ilookup(sb, ino);
++	if (!inode)
++		goto out;
++
++	if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
++		pr_warn("wrong root branch\n");
++		iput(inode);
++		inode = NULL;
++		goto out;
++	}
++
++	ii_write_lock_child(inode);
++
++out:
++	return inode;
++}
++
++static void au_hn_bh(void *_args)
++{
++	struct au_hnotify_args *a = _args;
++	struct super_block *sb;
++	aufs_bindex_t bindex, bend, bfound;
++	unsigned char xino, try_iput;
++	int err;
++	struct inode *inode;
++	ino_t h_ino;
++	struct hn_job_args args;
++	struct dentry *dentry;
++	struct au_sbinfo *sbinfo;
++
++	AuDebugOn(!_args);
++	AuDebugOn(!a->h_dir);
++	AuDebugOn(!a->dir);
++	AuDebugOn(!a->mask);
++	AuDbg("mask 0x%x, i%lu, hi%lu, hci%lu\n",
++	      a->mask, a->dir->i_ino, a->h_dir->i_ino,
++	      a->h_child_inode ? a->h_child_inode->i_ino : 0);
++
++	inode = NULL;
++	dentry = NULL;
++	/*
++	 * do not lock a->dir->i_mutex here
++	 * because of d_revalidate() may cause a deadlock.
++	 */
++	sb = a->dir->i_sb;
++	AuDebugOn(!sb);
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!sbinfo);
++	si_write_lock(sb, AuLock_NOPLMW);
++
++	ii_read_lock_parent(a->dir);
++	bfound = -1;
++	bend = au_ibend(a->dir);
++	for (bindex = au_ibstart(a->dir); bindex <= bend; bindex++)
++		if (au_h_iptr(a->dir, bindex) == a->h_dir) {
++			bfound = bindex;
++			break;
++		}
++	ii_read_unlock(a->dir);
++	if (unlikely(bfound < 0))
++		goto out;
++
++	xino = !!au_opt_test(au_mntflags(sb), XINO);
++	h_ino = 0;
++	if (a->h_child_inode)
++		h_ino = a->h_child_inode->i_ino;
++
++	if (a->h_child_nlen
++	    && (au_ftest_hnjob(a->flags[AuHn_CHILD], GEN)
++		|| au_ftest_hnjob(a->flags[AuHn_CHILD], MNTPNT)))
++		dentry = lookup_wlock_by_name(a->h_child_name, a->h_child_nlen,
++					      a->dir);
++	try_iput = 0;
++	if (dentry)
++		inode = dentry->d_inode;
++	if (xino && !inode && h_ino
++	    && (au_ftest_hnjob(a->flags[AuHn_CHILD], XINO0)
++		|| au_ftest_hnjob(a->flags[AuHn_CHILD], TRYXINO0)
++		|| au_ftest_hnjob(a->flags[AuHn_CHILD], GEN))) {
++		inode = lookup_wlock_by_ino(sb, bfound, h_ino);
++		try_iput = 1;
++	    }
++
++	args.flags = a->flags[AuHn_CHILD];
++	args.dentry = dentry;
++	args.inode = inode;
++	args.h_inode = a->h_child_inode;
++	args.dir = a->dir;
++	args.h_dir = a->h_dir;
++	args.h_name = a->h_child_name;
++	args.h_nlen = a->h_child_nlen;
++	err = hn_job(&args);
++	if (dentry) {
++		if (au_di(dentry))
++			di_write_unlock(dentry);
++		dput(dentry);
++	}
++	if (inode && try_iput) {
++		ii_write_unlock(inode);
++		iput(inode);
++	}
++
++	ii_write_lock_parent(a->dir);
++	args.flags = a->flags[AuHn_PARENT];
++	args.dentry = NULL;
++	args.inode = a->dir;
++	args.h_inode = a->h_dir;
++	args.dir = NULL;
++	args.h_dir = NULL;
++	args.h_name = NULL;
++	args.h_nlen = 0;
++	err = hn_job(&args);
++	ii_write_unlock(a->dir);
++
++out:
++	iput(a->h_child_inode);
++	iput(a->h_dir);
++	iput(a->dir);
++	si_write_unlock(sb);
++	au_nwt_done(&sbinfo->si_nowait);
++	kfree(a);
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_hnotify(struct inode *h_dir, struct au_hnotify *hnotify, u32 mask,
++	       struct qstr *h_child_qstr, struct inode *h_child_inode)
++{
++	int err, len;
++	unsigned int flags[AuHnLast], f;
++	unsigned char isdir, isroot, wh;
++	struct inode *dir;
++	struct au_hnotify_args *args;
++	char *p, *h_child_name;
++
++	err = 0;
++	AuDebugOn(!hnotify || !hnotify->hn_aufs_inode);
++	dir = igrab(hnotify->hn_aufs_inode);
++	if (!dir)
++		goto out;
++
++	isroot = (dir->i_ino == AUFS_ROOT_INO);
++	wh = 0;
++	h_child_name = (void *)h_child_qstr->name;
++	len = h_child_qstr->len;
++	if (h_child_name) {
++		if (len > AUFS_WH_PFX_LEN
++		    && !memcmp(h_child_name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
++			h_child_name += AUFS_WH_PFX_LEN;
++			len -= AUFS_WH_PFX_LEN;
++			wh = 1;
++		}
++	}
++
++	isdir = 0;
++	if (h_child_inode)
++		isdir = !!S_ISDIR(h_child_inode->i_mode);
++	flags[AuHn_PARENT] = AuHnJob_ISDIR;
++	flags[AuHn_CHILD] = 0;
++	if (isdir)
++		flags[AuHn_CHILD] = AuHnJob_ISDIR;
++	au_fset_hnjob(flags[AuHn_PARENT], DIRENT);
++	au_fset_hnjob(flags[AuHn_CHILD], GEN);
++	switch (mask & FS_EVENTS_POSS_ON_CHILD) {
++	case FS_MOVED_FROM:
++	case FS_MOVED_TO:
++		au_fset_hnjob(flags[AuHn_CHILD], XINO0);
++		au_fset_hnjob(flags[AuHn_CHILD], MNTPNT);
++		/*FALLTHROUGH*/
++	case FS_CREATE:
++		AuDebugOn(!h_child_name);
++		break;
++
++	case FS_DELETE:
++		/*
++		 * aufs never be able to get this child inode.
++		 * revalidation should be in d_revalidate()
++		 * by checking i_nlink, i_generation or d_unhashed().
++		 */
++		AuDebugOn(!h_child_name);
++		au_fset_hnjob(flags[AuHn_CHILD], TRYXINO0);
++		au_fset_hnjob(flags[AuHn_CHILD], MNTPNT);
++		break;
++
++	default:
++		AuDebugOn(1);
++	}
++
++	if (wh)
++		h_child_inode = NULL;
++
++	err = -ENOMEM;
++	/* iput() and kfree() will be called in au_hnotify() */
++	args = kmalloc(sizeof(*args) + len + 1, GFP_NOFS);
++	if (unlikely(!args)) {
++		AuErr1("no memory\n");
++		iput(dir);
++		goto out;
++	}
++	args->flags[AuHn_PARENT] = flags[AuHn_PARENT];
++	args->flags[AuHn_CHILD] = flags[AuHn_CHILD];
++	args->mask = mask;
++	args->dir = dir;
++	args->h_dir = igrab(h_dir);
++	if (h_child_inode)
++		h_child_inode = igrab(h_child_inode); /* can be NULL */
++	args->h_child_inode = h_child_inode;
++	args->h_child_nlen = len;
++	if (len) {
++		p = (void *)args;
++		p += sizeof(*args);
++		memcpy(p, h_child_name, len);
++		p[len] = 0;
++	}
++
++	/* NFS fires the event for silly-renamed one from kworker */
++	f = 0;
++	if (!dir->i_nlink
++	    || (au_test_nfs(h_dir->i_sb) && (mask & FS_DELETE)))
++		f = AuWkq_NEST;
++	err = au_wkq_nowait(au_hn_bh, args, dir->i_sb, f);
++	if (unlikely(err)) {
++		pr_err("wkq %d\n", err);
++		iput(args->h_child_inode);
++		iput(args->h_dir);
++		iput(args->dir);
++		kfree(args);
++	}
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_hnotify_reset_br(unsigned int udba, struct au_branch *br, int perm)
++{
++	int err;
++
++	AuDebugOn(!(udba & AuOptMask_UDBA));
++
++	err = 0;
++	if (au_hnotify_op.reset_br)
++		err = au_hnotify_op.reset_br(udba, br, perm);
++
++	return err;
++}
++
++int au_hnotify_init_br(struct au_branch *br, int perm)
++{
++	int err;
++
++	err = 0;
++	if (au_hnotify_op.init_br)
++		err = au_hnotify_op.init_br(br, perm);
++
++	return err;
++}
++
++void au_hnotify_fin_br(struct au_branch *br)
++{
++	if (au_hnotify_op.fin_br)
++		au_hnotify_op.fin_br(br);
++}
++
++static void au_hn_destroy_cache(void)
++{
++	kmem_cache_destroy(au_cachep[AuCache_HNOTIFY]);
++	au_cachep[AuCache_HNOTIFY] = NULL;
++}
++
++int __init au_hnotify_init(void)
++{
++	int err;
++
++	err = -ENOMEM;
++	au_cachep[AuCache_HNOTIFY] = AuCache(au_hnotify);
++	if (au_cachep[AuCache_HNOTIFY]) {
++		err = 0;
++		if (au_hnotify_op.init)
++			err = au_hnotify_op.init();
++		if (unlikely(err))
++			au_hn_destroy_cache();
++	}
++	AuTraceErr(err);
++	return err;
++}
++
++void au_hnotify_fin(void)
++{
++	if (au_hnotify_op.fin)
++		au_hnotify_op.fin();
++	/* cf. au_cache_fin() */
++	if (au_cachep[AuCache_HNOTIFY])
++		au_hn_destroy_cache();
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/iinfo.c linux-4.0.4/fs/aufs/iinfo.c
+--- linux-4.0.4.orig/fs/aufs/iinfo.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/iinfo.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,264 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * inode private data
++ */
++
++#include "aufs.h"
++
++struct inode *au_h_iptr(struct inode *inode, aufs_bindex_t bindex)
++{
++	struct inode *h_inode;
++
++	IiMustAnyLock(inode);
++
++	h_inode = au_ii(inode)->ii_hinode[0 + bindex].hi_inode;
++	AuDebugOn(h_inode && atomic_read(&h_inode->i_count) <= 0);
++	return h_inode;
++}
++
++/* todo: hard/soft set? */
++void au_hiput(struct au_hinode *hinode)
++{
++	au_hn_free(hinode);
++	dput(hinode->hi_whdentry);
++	iput(hinode->hi_inode);
++}
++
++unsigned int au_hi_flags(struct inode *inode, int isdir)
++{
++	unsigned int flags;
++	const unsigned int mnt_flags = au_mntflags(inode->i_sb);
++
++	flags = 0;
++	if (au_opt_test(mnt_flags, XINO))
++		au_fset_hi(flags, XINO);
++	if (isdir && au_opt_test(mnt_flags, UDBA_HNOTIFY))
++		au_fset_hi(flags, HNOTIFY);
++	return flags;
++}
++
++void au_set_h_iptr(struct inode *inode, aufs_bindex_t bindex,
++		   struct inode *h_inode, unsigned int flags)
++{
++	struct au_hinode *hinode;
++	struct inode *hi;
++	struct au_iinfo *iinfo = au_ii(inode);
++
++	IiMustWriteLock(inode);
++
++	hinode = iinfo->ii_hinode + bindex;
++	hi = hinode->hi_inode;
++	AuDebugOn(h_inode && atomic_read(&h_inode->i_count) <= 0);
++
++	if (hi)
++		au_hiput(hinode);
++	hinode->hi_inode = h_inode;
++	if (h_inode) {
++		int err;
++		struct super_block *sb = inode->i_sb;
++		struct au_branch *br;
++
++		AuDebugOn(inode->i_mode
++			  && (h_inode->i_mode & S_IFMT)
++			  != (inode->i_mode & S_IFMT));
++		if (bindex == iinfo->ii_bstart)
++			au_cpup_igen(inode, h_inode);
++		br = au_sbr(sb, bindex);
++		hinode->hi_id = br->br_id;
++		if (au_ftest_hi(flags, XINO)) {
++			err = au_xino_write(sb, bindex, h_inode->i_ino,
++					    inode->i_ino);
++			if (unlikely(err))
++				AuIOErr1("failed au_xino_write() %d\n", err);
++		}
++
++		if (au_ftest_hi(flags, HNOTIFY)
++		    && au_br_hnotifyable(br->br_perm)) {
++			err = au_hn_alloc(hinode, inode);
++			if (unlikely(err))
++				AuIOErr1("au_hn_alloc() %d\n", err);
++		}
++	}
++}
++
++void au_set_hi_wh(struct inode *inode, aufs_bindex_t bindex,
++		  struct dentry *h_wh)
++{
++	struct au_hinode *hinode;
++
++	IiMustWriteLock(inode);
++
++	hinode = au_ii(inode)->ii_hinode + bindex;
++	AuDebugOn(hinode->hi_whdentry);
++	hinode->hi_whdentry = h_wh;
++}
++
++void au_update_iigen(struct inode *inode, int half)
++{
++	struct au_iinfo *iinfo;
++	struct au_iigen *iigen;
++	unsigned int sigen;
++
++	sigen = au_sigen(inode->i_sb);
++	iinfo = au_ii(inode);
++	iigen = &iinfo->ii_generation;
++	spin_lock(&iinfo->ii_genspin);
++	iigen->ig_generation = sigen;
++	if (half)
++		au_ig_fset(iigen->ig_flags, HALF_REFRESHED);
++	else
++		au_ig_fclr(iigen->ig_flags, HALF_REFRESHED);
++	spin_unlock(&iinfo->ii_genspin);
++}
++
++/* it may be called at remount time, too */
++void au_update_ibrange(struct inode *inode, int do_put_zero)
++{
++	struct au_iinfo *iinfo;
++	aufs_bindex_t bindex, bend;
++
++	iinfo = au_ii(inode);
++	if (!iinfo)
++		return;
++
++	IiMustWriteLock(inode);
++
++	if (do_put_zero && iinfo->ii_bstart >= 0) {
++		for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend;
++		     bindex++) {
++			struct inode *h_i;
++
++			h_i = iinfo->ii_hinode[0 + bindex].hi_inode;
++			if (h_i
++			    && !h_i->i_nlink
++			    && !(h_i->i_state & I_LINKABLE))
++				au_set_h_iptr(inode, bindex, NULL, 0);
++		}
++	}
++
++	iinfo->ii_bstart = -1;
++	iinfo->ii_bend = -1;
++	bend = au_sbend(inode->i_sb);
++	for (bindex = 0; bindex <= bend; bindex++)
++		if (iinfo->ii_hinode[0 + bindex].hi_inode) {
++			iinfo->ii_bstart = bindex;
++			break;
++		}
++	if (iinfo->ii_bstart >= 0)
++		for (bindex = bend; bindex >= iinfo->ii_bstart; bindex--)
++			if (iinfo->ii_hinode[0 + bindex].hi_inode) {
++				iinfo->ii_bend = bindex;
++				break;
++			}
++	AuDebugOn(iinfo->ii_bstart > iinfo->ii_bend);
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_icntnr_init_once(void *_c)
++{
++	struct au_icntnr *c = _c;
++	struct au_iinfo *iinfo = &c->iinfo;
++	static struct lock_class_key aufs_ii;
++
++	spin_lock_init(&iinfo->ii_genspin);
++	au_rw_init(&iinfo->ii_rwsem);
++	au_rw_class(&iinfo->ii_rwsem, &aufs_ii);
++	inode_init_once(&c->vfs_inode);
++}
++
++int au_iinfo_init(struct inode *inode)
++{
++	struct au_iinfo *iinfo;
++	struct super_block *sb;
++	int nbr, i;
++
++	sb = inode->i_sb;
++	iinfo = &(container_of(inode, struct au_icntnr, vfs_inode)->iinfo);
++	nbr = au_sbend(sb) + 1;
++	if (unlikely(nbr <= 0))
++		nbr = 1;
++	iinfo->ii_hinode = kcalloc(nbr, sizeof(*iinfo->ii_hinode), GFP_NOFS);
++	if (iinfo->ii_hinode) {
++		au_ninodes_inc(sb);
++		for (i = 0; i < nbr; i++)
++			iinfo->ii_hinode[i].hi_id = -1;
++
++		iinfo->ii_generation.ig_generation = au_sigen(sb);
++		iinfo->ii_bstart = -1;
++		iinfo->ii_bend = -1;
++		iinfo->ii_vdir = NULL;
++		return 0;
++	}
++	return -ENOMEM;
++}
++
++int au_ii_realloc(struct au_iinfo *iinfo, int nbr)
++{
++	int err, sz;
++	struct au_hinode *hip;
++
++	AuRwMustWriteLock(&iinfo->ii_rwsem);
++
++	err = -ENOMEM;
++	sz = sizeof(*hip) * (iinfo->ii_bend + 1);
++	if (!sz)
++		sz = sizeof(*hip);
++	hip = au_kzrealloc(iinfo->ii_hinode, sz, sizeof(*hip) * nbr, GFP_NOFS);
++	if (hip) {
++		iinfo->ii_hinode = hip;
++		err = 0;
++	}
++
++	return err;
++}
++
++void au_iinfo_fin(struct inode *inode)
++{
++	struct au_iinfo *iinfo;
++	struct au_hinode *hi;
++	struct super_block *sb;
++	aufs_bindex_t bindex, bend;
++	const unsigned char unlinked = !inode->i_nlink;
++
++	iinfo = au_ii(inode);
++	/* bad_inode case */
++	if (!iinfo)
++		return;
++
++	sb = inode->i_sb;
++	au_ninodes_dec(sb);
++	if (si_pid_test(sb))
++		au_xino_delete_inode(inode, unlinked);
++	else {
++		/*
++		 * it is safe to hide the dependency between sbinfo and
++		 * sb->s_umount.
++		 */
++		lockdep_off();
++		si_noflush_read_lock(sb);
++		au_xino_delete_inode(inode, unlinked);
++		si_read_unlock(sb);
++		lockdep_on();
++	}
++
++	if (iinfo->ii_vdir)
++		au_vdir_free(iinfo->ii_vdir);
++
++	bindex = iinfo->ii_bstart;
++	if (bindex >= 0) {
++		hi = iinfo->ii_hinode + bindex;
++		bend = iinfo->ii_bend;
++		while (bindex++ <= bend) {
++			if (hi->hi_inode)
++				au_hiput(hi);
++			hi++;
++		}
++	}
++	kfree(iinfo->ii_hinode);
++	iinfo->ii_hinode = NULL;
++	AuRwDestroy(&iinfo->ii_rwsem);
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/inode.c linux-4.0.4/fs/aufs/inode.c
+--- linux-4.0.4.orig/fs/aufs/inode.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/inode.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,482 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * inode functions
++ */
++
++#include "aufs.h"
++
++struct inode *au_igrab(struct inode *inode)
++{
++	if (inode) {
++		AuDebugOn(!atomic_read(&inode->i_count));
++		ihold(inode);
++	}
++	return inode;
++}
++
++static void au_refresh_hinode_attr(struct inode *inode, int do_version)
++{
++	au_cpup_attr_all(inode, /*force*/0);
++	au_update_iigen(inode, /*half*/1);
++	if (do_version)
++		inode->i_version++;
++}
++
++static int au_ii_refresh(struct inode *inode, int *update)
++{
++	int err, e;
++	umode_t type;
++	aufs_bindex_t bindex, new_bindex;
++	struct super_block *sb;
++	struct au_iinfo *iinfo;
++	struct au_hinode *p, *q, tmp;
++
++	IiMustWriteLock(inode);
++
++	*update = 0;
++	sb = inode->i_sb;
++	type = inode->i_mode & S_IFMT;
++	iinfo = au_ii(inode);
++	err = au_ii_realloc(iinfo, au_sbend(sb) + 1);
++	if (unlikely(err))
++		goto out;
++
++	AuDebugOn(iinfo->ii_bstart < 0);
++	p = iinfo->ii_hinode + iinfo->ii_bstart;
++	for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend;
++	     bindex++, p++) {
++		if (!p->hi_inode)
++			continue;
++
++		AuDebugOn(type != (p->hi_inode->i_mode & S_IFMT));
++		new_bindex = au_br_index(sb, p->hi_id);
++		if (new_bindex == bindex)
++			continue;
++
++		if (new_bindex < 0) {
++			*update = 1;
++			au_hiput(p);
++			p->hi_inode = NULL;
++			continue;
++		}
++
++		if (new_bindex < iinfo->ii_bstart)
++			iinfo->ii_bstart = new_bindex;
++		if (iinfo->ii_bend < new_bindex)
++			iinfo->ii_bend = new_bindex;
++		/* swap two lower inode, and loop again */
++		q = iinfo->ii_hinode + new_bindex;
++		tmp = *q;
++		*q = *p;
++		*p = tmp;
++		if (tmp.hi_inode) {
++			bindex--;
++			p--;
++		}
++	}
++	au_update_ibrange(inode, /*do_put_zero*/0);
++	e = au_dy_irefresh(inode);
++	if (unlikely(e && !err))
++		err = e;
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++int au_refresh_hinode_self(struct inode *inode)
++{
++	int err, update;
++
++	err = au_ii_refresh(inode, &update);
++	if (!err)
++		au_refresh_hinode_attr(inode, update && S_ISDIR(inode->i_mode));
++
++	AuTraceErr(err);
++	return err;
++}
++
++int au_refresh_hinode(struct inode *inode, struct dentry *dentry)
++{
++	int err, e, update;
++	unsigned int flags;
++	umode_t mode;
++	aufs_bindex_t bindex, bend;
++	unsigned char isdir;
++	struct au_hinode *p;
++	struct au_iinfo *iinfo;
++
++	err = au_ii_refresh(inode, &update);
++	if (unlikely(err))
++		goto out;
++
++	update = 0;
++	iinfo = au_ii(inode);
++	p = iinfo->ii_hinode + iinfo->ii_bstart;
++	mode = (inode->i_mode & S_IFMT);
++	isdir = S_ISDIR(mode);
++	flags = au_hi_flags(inode, isdir);
++	bend = au_dbend(dentry);
++	for (bindex = au_dbstart(dentry); bindex <= bend; bindex++) {
++		struct inode *h_i;
++		struct dentry *h_d;
++
++		h_d = au_h_dptr(dentry, bindex);
++		if (!h_d || !h_d->d_inode)
++			continue;
++
++		AuDebugOn(mode != (h_d->d_inode->i_mode & S_IFMT));
++		if (iinfo->ii_bstart <= bindex && bindex <= iinfo->ii_bend) {
++			h_i = au_h_iptr(inode, bindex);
++			if (h_i) {
++				if (h_i == h_d->d_inode)
++					continue;
++				err = -EIO;
++				break;
++			}
++		}
++		if (bindex < iinfo->ii_bstart)
++			iinfo->ii_bstart = bindex;
++		if (iinfo->ii_bend < bindex)
++			iinfo->ii_bend = bindex;
++		au_set_h_iptr(inode, bindex, au_igrab(h_d->d_inode), flags);
++		update = 1;
++	}
++	au_update_ibrange(inode, /*do_put_zero*/0);
++	e = au_dy_irefresh(inode);
++	if (unlikely(e && !err))
++		err = e;
++	if (!err)
++		au_refresh_hinode_attr(inode, update && isdir);
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int set_inode(struct inode *inode, struct dentry *dentry)
++{
++	int err;
++	unsigned int flags;
++	umode_t mode;
++	aufs_bindex_t bindex, bstart, btail;
++	unsigned char isdir;
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++	struct au_iinfo *iinfo;
++
++	IiMustWriteLock(inode);
++
++	err = 0;
++	isdir = 0;
++	bstart = au_dbstart(dentry);
++	h_inode = au_h_dptr(dentry, bstart)->d_inode;
++	mode = h_inode->i_mode;
++	switch (mode & S_IFMT) {
++	case S_IFREG:
++		btail = au_dbtail(dentry);
++		inode->i_op = &aufs_iop;
++		inode->i_fop = &aufs_file_fop;
++		err = au_dy_iaop(inode, bstart, h_inode);
++		if (unlikely(err))
++			goto out;
++		break;
++	case S_IFDIR:
++		isdir = 1;
++		btail = au_dbtaildir(dentry);
++		inode->i_op = &aufs_dir_iop;
++		inode->i_fop = &aufs_dir_fop;
++		break;
++	case S_IFLNK:
++		btail = au_dbtail(dentry);
++		inode->i_op = &aufs_symlink_iop;
++		break;
++	case S_IFBLK:
++	case S_IFCHR:
++	case S_IFIFO:
++	case S_IFSOCK:
++		btail = au_dbtail(dentry);
++		inode->i_op = &aufs_iop;
++		init_special_inode(inode, mode, h_inode->i_rdev);
++		break;
++	default:
++		AuIOErr("Unknown file type 0%o\n", mode);
++		err = -EIO;
++		goto out;
++	}
++
++	/* do not set hnotify for whiteouted dirs (SHWH mode) */
++	flags = au_hi_flags(inode, isdir);
++	if (au_opt_test(au_mntflags(dentry->d_sb), SHWH)
++	    && au_ftest_hi(flags, HNOTIFY)
++	    && dentry->d_name.len > AUFS_WH_PFX_LEN
++	    && !memcmp(dentry->d_name.name, AUFS_WH_PFX, AUFS_WH_PFX_LEN))
++		au_fclr_hi(flags, HNOTIFY);
++	iinfo = au_ii(inode);
++	iinfo->ii_bstart = bstart;
++	iinfo->ii_bend = btail;
++	for (bindex = bstart; bindex <= btail; bindex++) {
++		h_dentry = au_h_dptr(dentry, bindex);
++		if (h_dentry)
++			au_set_h_iptr(inode, bindex,
++				      au_igrab(h_dentry->d_inode), flags);
++	}
++	au_cpup_attr_all(inode, /*force*/1);
++	/*
++	 * to force calling aufs_get_acl() every time,
++	 * do not call cache_no_acl() for aufs inode.
++	 */
++
++out:
++	return err;
++}
++
++/*
++ * successful returns with iinfo write_locked
++ * minus: errno
++ * zero: success, matched
++ * plus: no error, but unmatched
++ */
++static int reval_inode(struct inode *inode, struct dentry *dentry)
++{
++	int err;
++	unsigned int gen;
++	struct au_iigen iigen;
++	aufs_bindex_t bindex, bend;
++	struct inode *h_inode, *h_dinode;
++
++	/*
++	 * before this function, if aufs got any iinfo lock, it must be only
++	 * one, the parent dir.
++	 * it can happen by UDBA and the obsoleted inode number.
++	 */
++	err = -EIO;
++	if (unlikely(inode->i_ino == parent_ino(dentry)))
++		goto out;
++
++	err = 1;
++	ii_write_lock_new_child(inode);
++	h_dinode = au_h_dptr(dentry, au_dbstart(dentry))->d_inode;
++	bend = au_ibend(inode);
++	for (bindex = au_ibstart(inode); bindex <= bend; bindex++) {
++		h_inode = au_h_iptr(inode, bindex);
++		if (!h_inode || h_inode != h_dinode)
++			continue;
++
++		err = 0;
++		gen = au_iigen(inode, &iigen);
++		if (gen == au_digen(dentry)
++		    && !au_ig_ftest(iigen.ig_flags, HALF_REFRESHED))
++			break;
++
++		/* fully refresh inode using dentry */
++		err = au_refresh_hinode(inode, dentry);
++		if (!err)
++			au_update_iigen(inode, /*half*/0);
++		break;
++	}
++
++	if (unlikely(err))
++		ii_write_unlock(inode);
++out:
++	return err;
++}
++
++int au_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++	   unsigned int d_type, ino_t *ino)
++{
++	int err;
++	struct mutex *mtx;
++
++	/* prevent hardlinked inode number from race condition */
++	mtx = NULL;
++	if (d_type != DT_DIR) {
++		mtx = &au_sbr(sb, bindex)->br_xino.xi_nondir_mtx;
++		mutex_lock(mtx);
++	}
++	err = au_xino_read(sb, bindex, h_ino, ino);
++	if (unlikely(err))
++		goto out;
++
++	if (!*ino) {
++		err = -EIO;
++		*ino = au_xino_new_ino(sb);
++		if (unlikely(!*ino))
++			goto out;
++		err = au_xino_write(sb, bindex, h_ino, *ino);
++		if (unlikely(err))
++			goto out;
++	}
++
++out:
++	if (mtx)
++		mutex_unlock(mtx);
++	return err;
++}
++
++/* successful returns with iinfo write_locked */
++/* todo: return with unlocked? */
++struct inode *au_new_inode(struct dentry *dentry, int must_new)
++{
++	struct inode *inode;
++	struct dentry *h_dentry;
++	struct super_block *sb;
++	struct mutex *mtx;
++	ino_t h_ino, ino;
++	int err;
++	aufs_bindex_t bstart;
++
++	sb = dentry->d_sb;
++	bstart = au_dbstart(dentry);
++	h_dentry = au_h_dptr(dentry, bstart);
++	h_ino = h_dentry->d_inode->i_ino;
++
++	/*
++	 * stop 'race'-ing between hardlinks under different
++	 * parents.
++	 */
++	mtx = NULL;
++	if (!d_is_dir(h_dentry))
++		mtx = &au_sbr(sb, bstart)->br_xino.xi_nondir_mtx;
++
++new_ino:
++	if (mtx)
++		mutex_lock(mtx);
++	err = au_xino_read(sb, bstart, h_ino, &ino);
++	inode = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++
++	if (!ino) {
++		ino = au_xino_new_ino(sb);
++		if (unlikely(!ino)) {
++			inode = ERR_PTR(-EIO);
++			goto out;
++		}
++	}
++
++	AuDbg("i%lu\n", (unsigned long)ino);
++	inode = au_iget_locked(sb, ino);
++	err = PTR_ERR(inode);
++	if (IS_ERR(inode))
++		goto out;
++
++	AuDbg("%lx, new %d\n", inode->i_state, !!(inode->i_state & I_NEW));
++	if (inode->i_state & I_NEW) {
++		/* verbose coding for lock class name */
++		if (unlikely(d_is_symlink(h_dentry)))
++			au_rw_class(&au_ii(inode)->ii_rwsem,
++				    au_lc_key + AuLcSymlink_IIINFO);
++		else if (unlikely(d_is_dir(h_dentry)))
++			au_rw_class(&au_ii(inode)->ii_rwsem,
++				    au_lc_key + AuLcDir_IIINFO);
++		else /* likely */
++			au_rw_class(&au_ii(inode)->ii_rwsem,
++				    au_lc_key + AuLcNonDir_IIINFO);
++
++		ii_write_lock_new_child(inode);
++		err = set_inode(inode, dentry);
++		if (!err) {
++			unlock_new_inode(inode);
++			goto out; /* success */
++		}
++
++		/*
++		 * iget_failed() calls iput(), but we need to call
++		 * ii_write_unlock() after iget_failed(). so dirty hack for
++		 * i_count.
++		 */
++		atomic_inc(&inode->i_count);
++		iget_failed(inode);
++		ii_write_unlock(inode);
++		au_xino_write(sb, bstart, h_ino, /*ino*/0);
++		/* ignore this error */
++		goto out_iput;
++	} else if (!must_new && !IS_DEADDIR(inode) && inode->i_nlink) {
++		/*
++		 * horrible race condition between lookup, readdir and copyup
++		 * (or something).
++		 */
++		if (mtx)
++			mutex_unlock(mtx);
++		err = reval_inode(inode, dentry);
++		if (unlikely(err < 0)) {
++			mtx = NULL;
++			goto out_iput;
++		}
++
++		if (!err) {
++			mtx = NULL;
++			goto out; /* success */
++		} else if (mtx)
++			mutex_lock(mtx);
++	}
++
++	if (unlikely(au_test_fs_unique_ino(h_dentry->d_inode)))
++		AuWarn1("Warning: Un-notified UDBA or repeatedly renamed dir,"
++			" b%d, %s, %pd, hi%lu, i%lu.\n",
++			bstart, au_sbtype(h_dentry->d_sb), dentry,
++			(unsigned long)h_ino, (unsigned long)ino);
++	ino = 0;
++	err = au_xino_write(sb, bstart, h_ino, /*ino*/0);
++	if (!err) {
++		iput(inode);
++		if (mtx)
++			mutex_unlock(mtx);
++		goto new_ino;
++	}
++
++out_iput:
++	iput(inode);
++	inode = ERR_PTR(err);
++out:
++	if (mtx)
++		mutex_unlock(mtx);
++	return inode;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
++	       struct inode *inode)
++{
++	int err;
++	struct inode *hi;
++
++	err = au_br_rdonly(au_sbr(sb, bindex));
++
++	/* pseudo-link after flushed may happen out of bounds */
++	if (!err
++	    && inode
++	    && au_ibstart(inode) <= bindex
++	    && bindex <= au_ibend(inode)) {
++		/*
++		 * permission check is unnecessary since vfsub routine
++		 * will be called later
++		 */
++		hi = au_h_iptr(inode, bindex);
++		if (hi)
++			err = IS_IMMUTABLE(hi) ? -EROFS : 0;
++	}
++
++	return err;
++}
++
++int au_test_h_perm(struct inode *h_inode, int mask)
++{
++	if (uid_eq(current_fsuid(), GLOBAL_ROOT_UID))
++		return 0;
++	return inode_permission(h_inode, mask);
++}
++
++int au_test_h_perm_sio(struct inode *h_inode, int mask)
++{
++	if (au_test_nfs(h_inode->i_sb)
++	    && (mask & MAY_WRITE)
++	    && S_ISDIR(h_inode->i_mode))
++		mask |= MAY_READ; /* force permission check */
++	return au_test_h_perm(h_inode, mask);
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/inode.h linux-4.0.4/fs/aufs/inode.h
+--- linux-4.0.4.orig/fs/aufs/inode.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/inode.h	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,660 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * inode operations
++ */
++
++#ifndef __AUFS_INODE_H__
++#define __AUFS_INODE_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fsnotify.h>
++#include "rwsem.h"
++
++struct vfsmount;
++
++struct au_hnotify {
++#ifdef CONFIG_AUFS_HNOTIFY
++#ifdef CONFIG_AUFS_HFSNOTIFY
++	/* never use fsnotify_add_vfsmount_mark() */
++	struct fsnotify_mark		hn_mark;
++#endif
++	struct inode			*hn_aufs_inode;	/* no get/put */
++#endif
++} ____cacheline_aligned_in_smp;
++
++struct au_hinode {
++	struct inode		*hi_inode;
++	aufs_bindex_t		hi_id;
++#ifdef CONFIG_AUFS_HNOTIFY
++	struct au_hnotify	*hi_notify;
++#endif
++
++	/* reference to the copied-up whiteout with get/put */
++	struct dentry		*hi_whdentry;
++};
++
++/* ig_flags */
++#define AuIG_HALF_REFRESHED		1
++#define au_ig_ftest(flags, name)	((flags) & AuIG_##name)
++#define au_ig_fset(flags, name) \
++	do { (flags) |= AuIG_##name; } while (0)
++#define au_ig_fclr(flags, name) \
++	do { (flags) &= ~AuIG_##name; } while (0)
++
++struct au_iigen {
++	__u32		ig_generation, ig_flags;
++};
++
++struct au_vdir;
++struct au_iinfo {
++	spinlock_t		ii_genspin;
++	struct au_iigen		ii_generation;
++	struct super_block	*ii_hsb1;	/* no get/put */
++
++	struct au_rwsem		ii_rwsem;
++	aufs_bindex_t		ii_bstart, ii_bend;
++	__u32			ii_higen;
++	struct au_hinode	*ii_hinode;
++	struct au_vdir		*ii_vdir;
++};
++
++struct au_icntnr {
++	struct au_iinfo iinfo;
++	struct inode vfs_inode;
++} ____cacheline_aligned_in_smp;
++
++/* au_pin flags */
++#define AuPin_DI_LOCKED		1
++#define AuPin_MNT_WRITE		(1 << 1)
++#define au_ftest_pin(flags, name)	((flags) & AuPin_##name)
++#define au_fset_pin(flags, name) \
++	do { (flags) |= AuPin_##name; } while (0)
++#define au_fclr_pin(flags, name) \
++	do { (flags) &= ~AuPin_##name; } while (0)
++
++struct au_pin {
++	/* input */
++	struct dentry *dentry;
++	unsigned int udba;
++	unsigned char lsc_di, lsc_hi, flags;
++	aufs_bindex_t bindex;
++
++	/* output */
++	struct dentry *parent;
++	struct au_hinode *hdir;
++	struct vfsmount *h_mnt;
++
++	/* temporary unlock/relock for copyup */
++	struct dentry *h_dentry, *h_parent;
++	struct au_branch *br;
++	struct task_struct *task;
++};
++
++void au_pin_hdir_unlock(struct au_pin *p);
++int au_pin_hdir_lock(struct au_pin *p);
++int au_pin_hdir_relock(struct au_pin *p);
++void au_pin_hdir_set_owner(struct au_pin *p, struct task_struct *task);
++void au_pin_hdir_acquire_nest(struct au_pin *p);
++void au_pin_hdir_release(struct au_pin *p);
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct au_iinfo *au_ii(struct inode *inode)
++{
++	struct au_iinfo *iinfo;
++
++	iinfo = &(container_of(inode, struct au_icntnr, vfs_inode)->iinfo);
++	if (iinfo->ii_hinode)
++		return iinfo;
++	return NULL; /* debugging bad_inode case */
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* inode.c */
++struct inode *au_igrab(struct inode *inode);
++int au_refresh_hinode_self(struct inode *inode);
++int au_refresh_hinode(struct inode *inode, struct dentry *dentry);
++int au_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++	   unsigned int d_type, ino_t *ino);
++struct inode *au_new_inode(struct dentry *dentry, int must_new);
++int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
++	       struct inode *inode);
++int au_test_h_perm(struct inode *h_inode, int mask);
++int au_test_h_perm_sio(struct inode *h_inode, int mask);
++
++static inline int au_wh_ino(struct super_block *sb, aufs_bindex_t bindex,
++			    ino_t h_ino, unsigned int d_type, ino_t *ino)
++{
++#ifdef CONFIG_AUFS_SHWH
++	return au_ino(sb, bindex, h_ino, d_type, ino);
++#else
++	return 0;
++#endif
++}
++
++/* i_op.c */
++extern struct inode_operations aufs_iop, aufs_symlink_iop, aufs_dir_iop;
++
++/* au_wr_dir flags */
++#define AuWrDir_ADD_ENTRY	1
++#define AuWrDir_ISDIR		(1 << 1)
++#define AuWrDir_TMPFILE		(1 << 2)
++#define au_ftest_wrdir(flags, name)	((flags) & AuWrDir_##name)
++#define au_fset_wrdir(flags, name) \
++	do { (flags) |= AuWrDir_##name; } while (0)
++#define au_fclr_wrdir(flags, name) \
++	do { (flags) &= ~AuWrDir_##name; } while (0)
++
++struct au_wr_dir_args {
++	aufs_bindex_t force_btgt;
++	unsigned char flags;
++};
++int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
++	      struct au_wr_dir_args *args);
++
++struct dentry *au_pinned_h_parent(struct au_pin *pin);
++void au_pin_init(struct au_pin *pin, struct dentry *dentry,
++		 aufs_bindex_t bindex, int lsc_di, int lsc_hi,
++		 unsigned int udba, unsigned char flags);
++int au_pin(struct au_pin *pin, struct dentry *dentry, aufs_bindex_t bindex,
++	   unsigned int udba, unsigned char flags) __must_check;
++int au_do_pin(struct au_pin *pin) __must_check;
++void au_unpin(struct au_pin *pin);
++int au_reval_for_attr(struct dentry *dentry, unsigned int sigen);
++
++#define AuIcpup_DID_CPUP	1
++#define au_ftest_icpup(flags, name)	((flags) & AuIcpup_##name)
++#define au_fset_icpup(flags, name) \
++	do { (flags) |= AuIcpup_##name; } while (0)
++#define au_fclr_icpup(flags, name) \
++	do { (flags) &= ~AuIcpup_##name; } while (0)
++
++struct au_icpup_args {
++	unsigned char flags;
++	unsigned char pin_flags;
++	aufs_bindex_t btgt;
++	unsigned int udba;
++	struct au_pin pin;
++	struct path h_path;
++	struct inode *h_inode;
++};
++
++int au_pin_and_icpup(struct dentry *dentry, struct iattr *ia,
++		     struct au_icpup_args *a);
++
++int au_h_path_getattr(struct dentry *dentry, int force, struct path *h_path);
++
++/* i_op_add.c */
++int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
++	       struct dentry *h_parent, int isdir);
++int aufs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
++	       dev_t dev);
++int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname);
++int aufs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
++		bool want_excl);
++struct vfsub_aopen_args;
++int au_aopen_or_create(struct inode *dir, struct dentry *dentry,
++		       struct vfsub_aopen_args *args);
++int aufs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode);
++int aufs_link(struct dentry *src_dentry, struct inode *dir,
++	      struct dentry *dentry);
++int aufs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
++
++/* i_op_del.c */
++int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup);
++int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
++	       struct dentry *h_parent, int isdir);
++int aufs_unlink(struct inode *dir, struct dentry *dentry);
++int aufs_rmdir(struct inode *dir, struct dentry *dentry);
++
++/* i_op_ren.c */
++int au_wbr(struct dentry *dentry, aufs_bindex_t btgt);
++int aufs_rename(struct inode *src_dir, struct dentry *src_dentry,
++		struct inode *dir, struct dentry *dentry);
++
++/* iinfo.c */
++struct inode *au_h_iptr(struct inode *inode, aufs_bindex_t bindex);
++void au_hiput(struct au_hinode *hinode);
++void au_set_hi_wh(struct inode *inode, aufs_bindex_t bindex,
++		  struct dentry *h_wh);
++unsigned int au_hi_flags(struct inode *inode, int isdir);
++
++/* hinode flags */
++#define AuHi_XINO	1
++#define AuHi_HNOTIFY	(1 << 1)
++#define au_ftest_hi(flags, name)	((flags) & AuHi_##name)
++#define au_fset_hi(flags, name) \
++	do { (flags) |= AuHi_##name; } while (0)
++#define au_fclr_hi(flags, name) \
++	do { (flags) &= ~AuHi_##name; } while (0)
++
++#ifndef CONFIG_AUFS_HNOTIFY
++#undef AuHi_HNOTIFY
++#define AuHi_HNOTIFY	0
++#endif
++
++void au_set_h_iptr(struct inode *inode, aufs_bindex_t bindex,
++		   struct inode *h_inode, unsigned int flags);
++
++void au_update_iigen(struct inode *inode, int half);
++void au_update_ibrange(struct inode *inode, int do_put_zero);
++
++void au_icntnr_init_once(void *_c);
++int au_iinfo_init(struct inode *inode);
++void au_iinfo_fin(struct inode *inode);
++int au_ii_realloc(struct au_iinfo *iinfo, int nbr);
++
++#ifdef CONFIG_PROC_FS
++/* plink.c */
++int au_plink_maint(struct super_block *sb, int flags);
++struct au_sbinfo;
++void au_plink_maint_leave(struct au_sbinfo *sbinfo);
++int au_plink_maint_enter(struct super_block *sb);
++#ifdef CONFIG_AUFS_DEBUG
++void au_plink_list(struct super_block *sb);
++#else
++AuStubVoid(au_plink_list, struct super_block *sb)
++#endif
++int au_plink_test(struct inode *inode);
++struct dentry *au_plink_lkup(struct inode *inode, aufs_bindex_t bindex);
++void au_plink_append(struct inode *inode, aufs_bindex_t bindex,
++		     struct dentry *h_dentry);
++void au_plink_put(struct super_block *sb, int verbose);
++void au_plink_clean(struct super_block *sb, int verbose);
++void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id);
++#else
++AuStubInt0(au_plink_maint, struct super_block *sb, int flags);
++AuStubVoid(au_plink_maint_leave, struct au_sbinfo *sbinfo);
++AuStubInt0(au_plink_maint_enter, struct super_block *sb);
++AuStubVoid(au_plink_list, struct super_block *sb);
++AuStubInt0(au_plink_test, struct inode *inode);
++AuStub(struct dentry *, au_plink_lkup, return NULL,
++       struct inode *inode, aufs_bindex_t bindex);
++AuStubVoid(au_plink_append, struct inode *inode, aufs_bindex_t bindex,
++	   struct dentry *h_dentry);
++AuStubVoid(au_plink_put, struct super_block *sb, int verbose);
++AuStubVoid(au_plink_clean, struct super_block *sb, int verbose);
++AuStubVoid(au_plink_half_refresh, struct super_block *sb, aufs_bindex_t br_id);
++#endif /* CONFIG_PROC_FS */
++
++#ifdef CONFIG_AUFS_XATTR
++/* xattr.c */
++int au_cpup_xattr(struct dentry *h_dst, struct dentry *h_src, int ignore_flags,
++		  unsigned int verbose);
++ssize_t aufs_listxattr(struct dentry *dentry, char *list, size_t size);
++ssize_t aufs_getxattr(struct dentry *dentry, const char *name, void *value,
++		      size_t size);
++int aufs_setxattr(struct dentry *dentry, const char *name, const void *value,
++		  size_t size, int flags);
++int aufs_removexattr(struct dentry *dentry, const char *name);
++
++/* void au_xattr_init(struct super_block *sb); */
++#else
++AuStubInt0(au_cpup_xattr, struct dentry *h_dst, struct dentry *h_src,
++	   int ignore_flags, unsigned int verbose);
++/* AuStubVoid(au_xattr_init, struct super_block *sb); */
++#endif
++
++#ifdef CONFIG_FS_POSIX_ACL
++struct posix_acl *aufs_get_acl(struct inode *inode, int type);
++int aufs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
++#endif
++
++#if IS_ENABLED(CONFIG_AUFS_XATTR) || IS_ENABLED(CONFIG_FS_POSIX_ACL)
++enum {
++	AU_XATTR_SET,
++	AU_XATTR_REMOVE,
++	AU_ACL_SET
++};
++
++struct au_srxattr {
++	int type;
++	union {
++		struct {
++			const char	*name;
++			const void	*value;
++			size_t		size;
++			int		flags;
++		} set;
++		struct {
++			const char	*name;
++		} remove;
++		struct {
++			struct posix_acl *acl;
++			int		type;
++		} acl_set;
++	} u;
++};
++ssize_t au_srxattr(struct dentry *dentry, struct au_srxattr *arg);
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++/* lock subclass for iinfo */
++enum {
++	AuLsc_II_CHILD,		/* child first */
++	AuLsc_II_CHILD2,	/* rename(2), link(2), and cpup at hnotify */
++	AuLsc_II_CHILD3,	/* copyup dirs */
++	AuLsc_II_PARENT,	/* see AuLsc_I_PARENT in vfsub.h */
++	AuLsc_II_PARENT2,
++	AuLsc_II_PARENT3,	/* copyup dirs */
++	AuLsc_II_NEW_CHILD
++};
++
++/*
++ * ii_read_lock_child, ii_write_lock_child,
++ * ii_read_lock_child2, ii_write_lock_child2,
++ * ii_read_lock_child3, ii_write_lock_child3,
++ * ii_read_lock_parent, ii_write_lock_parent,
++ * ii_read_lock_parent2, ii_write_lock_parent2,
++ * ii_read_lock_parent3, ii_write_lock_parent3,
++ * ii_read_lock_new_child, ii_write_lock_new_child,
++ */
++#define AuReadLockFunc(name, lsc) \
++static inline void ii_read_lock_##name(struct inode *i) \
++{ \
++	au_rw_read_lock_nested(&au_ii(i)->ii_rwsem, AuLsc_II_##lsc); \
++}
++
++#define AuWriteLockFunc(name, lsc) \
++static inline void ii_write_lock_##name(struct inode *i) \
++{ \
++	au_rw_write_lock_nested(&au_ii(i)->ii_rwsem, AuLsc_II_##lsc); \
++}
++
++#define AuRWLockFuncs(name, lsc) \
++	AuReadLockFunc(name, lsc) \
++	AuWriteLockFunc(name, lsc)
++
++AuRWLockFuncs(child, CHILD);
++AuRWLockFuncs(child2, CHILD2);
++AuRWLockFuncs(child3, CHILD3);
++AuRWLockFuncs(parent, PARENT);
++AuRWLockFuncs(parent2, PARENT2);
++AuRWLockFuncs(parent3, PARENT3);
++AuRWLockFuncs(new_child, NEW_CHILD);
++
++#undef AuReadLockFunc
++#undef AuWriteLockFunc
++#undef AuRWLockFuncs
++
++/*
++ * ii_read_unlock, ii_write_unlock, ii_downgrade_lock
++ */
++AuSimpleUnlockRwsemFuncs(ii, struct inode *i, &au_ii(i)->ii_rwsem);
++
++#define IiMustNoWaiters(i)	AuRwMustNoWaiters(&au_ii(i)->ii_rwsem)
++#define IiMustAnyLock(i)	AuRwMustAnyLock(&au_ii(i)->ii_rwsem)
++#define IiMustWriteLock(i)	AuRwMustWriteLock(&au_ii(i)->ii_rwsem)
++
++/* ---------------------------------------------------------------------- */
++
++static inline void au_icntnr_init(struct au_icntnr *c)
++{
++#ifdef CONFIG_AUFS_DEBUG
++	c->vfs_inode.i_mode = 0;
++#endif
++}
++
++static inline unsigned int au_iigen(struct inode *inode, struct au_iigen *iigen)
++{
++	unsigned int gen;
++	struct au_iinfo *iinfo;
++
++	iinfo = au_ii(inode);
++	spin_lock(&iinfo->ii_genspin);
++	if (iigen)
++		*iigen = iinfo->ii_generation;
++	gen = iinfo->ii_generation.ig_generation;
++	spin_unlock(&iinfo->ii_genspin);
++
++	return gen;
++}
++
++/* tiny test for inode number */
++/* tmpfs generation is too rough */
++static inline int au_test_higen(struct inode *inode, struct inode *h_inode)
++{
++	struct au_iinfo *iinfo;
++
++	iinfo = au_ii(inode);
++	AuRwMustAnyLock(&iinfo->ii_rwsem);
++	return !(iinfo->ii_hsb1 == h_inode->i_sb
++		 && iinfo->ii_higen == h_inode->i_generation);
++}
++
++static inline void au_iigen_dec(struct inode *inode)
++{
++	struct au_iinfo *iinfo;
++
++	iinfo = au_ii(inode);
++	spin_lock(&iinfo->ii_genspin);
++	iinfo->ii_generation.ig_generation--;
++	spin_unlock(&iinfo->ii_genspin);
++}
++
++static inline int au_iigen_test(struct inode *inode, unsigned int sigen)
++{
++	int err;
++
++	err = 0;
++	if (unlikely(inode && au_iigen(inode, NULL) != sigen))
++		err = -EIO;
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static inline aufs_bindex_t au_ii_br_id(struct inode *inode,
++					aufs_bindex_t bindex)
++{
++	IiMustAnyLock(inode);
++	return au_ii(inode)->ii_hinode[0 + bindex].hi_id;
++}
++
++static inline aufs_bindex_t au_ibstart(struct inode *inode)
++{
++	IiMustAnyLock(inode);
++	return au_ii(inode)->ii_bstart;
++}
++
++static inline aufs_bindex_t au_ibend(struct inode *inode)
++{
++	IiMustAnyLock(inode);
++	return au_ii(inode)->ii_bend;
++}
++
++static inline struct au_vdir *au_ivdir(struct inode *inode)
++{
++	IiMustAnyLock(inode);
++	return au_ii(inode)->ii_vdir;
++}
++
++static inline struct dentry *au_hi_wh(struct inode *inode, aufs_bindex_t bindex)
++{
++	IiMustAnyLock(inode);
++	return au_ii(inode)->ii_hinode[0 + bindex].hi_whdentry;
++}
++
++static inline void au_set_ibstart(struct inode *inode, aufs_bindex_t bindex)
++{
++	IiMustWriteLock(inode);
++	au_ii(inode)->ii_bstart = bindex;
++}
++
++static inline void au_set_ibend(struct inode *inode, aufs_bindex_t bindex)
++{
++	IiMustWriteLock(inode);
++	au_ii(inode)->ii_bend = bindex;
++}
++
++static inline void au_set_ivdir(struct inode *inode, struct au_vdir *vdir)
++{
++	IiMustWriteLock(inode);
++	au_ii(inode)->ii_vdir = vdir;
++}
++
++static inline struct au_hinode *au_hi(struct inode *inode, aufs_bindex_t bindex)
++{
++	IiMustAnyLock(inode);
++	return au_ii(inode)->ii_hinode + bindex;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct dentry *au_pinned_parent(struct au_pin *pin)
++{
++	if (pin)
++		return pin->parent;
++	return NULL;
++}
++
++static inline struct inode *au_pinned_h_dir(struct au_pin *pin)
++{
++	if (pin && pin->hdir)
++		return pin->hdir->hi_inode;
++	return NULL;
++}
++
++static inline struct au_hinode *au_pinned_hdir(struct au_pin *pin)
++{
++	if (pin)
++		return pin->hdir;
++	return NULL;
++}
++
++static inline void au_pin_set_dentry(struct au_pin *pin, struct dentry *dentry)
++{
++	if (pin)
++		pin->dentry = dentry;
++}
++
++static inline void au_pin_set_parent_lflag(struct au_pin *pin,
++					   unsigned char lflag)
++{
++	if (pin) {
++		if (lflag)
++			au_fset_pin(pin->flags, DI_LOCKED);
++		else
++			au_fclr_pin(pin->flags, DI_LOCKED);
++	}
++}
++
++#if 0 /* reserved */
++static inline void au_pin_set_parent(struct au_pin *pin, struct dentry *parent)
++{
++	if (pin) {
++		dput(pin->parent);
++		pin->parent = dget(parent);
++	}
++}
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++struct au_branch;
++#ifdef CONFIG_AUFS_HNOTIFY
++struct au_hnotify_op {
++	void (*ctl)(struct au_hinode *hinode, int do_set);
++	int (*alloc)(struct au_hinode *hinode);
++
++	/*
++	 * if it returns true, the the caller should free hinode->hi_notify,
++	 * otherwise ->free() frees it.
++	 */
++	int (*free)(struct au_hinode *hinode,
++		    struct au_hnotify *hn) __must_check;
++
++	void (*fin)(void);
++	int (*init)(void);
++
++	int (*reset_br)(unsigned int udba, struct au_branch *br, int perm);
++	void (*fin_br)(struct au_branch *br);
++	int (*init_br)(struct au_branch *br, int perm);
++};
++
++/* hnotify.c */
++int au_hn_alloc(struct au_hinode *hinode, struct inode *inode);
++void au_hn_free(struct au_hinode *hinode);
++void au_hn_ctl(struct au_hinode *hinode, int do_set);
++void au_hn_reset(struct inode *inode, unsigned int flags);
++int au_hnotify(struct inode *h_dir, struct au_hnotify *hnotify, u32 mask,
++	       struct qstr *h_child_qstr, struct inode *h_child_inode);
++int au_hnotify_reset_br(unsigned int udba, struct au_branch *br, int perm);
++int au_hnotify_init_br(struct au_branch *br, int perm);
++void au_hnotify_fin_br(struct au_branch *br);
++int __init au_hnotify_init(void);
++void au_hnotify_fin(void);
++
++/* hfsnotify.c */
++extern const struct au_hnotify_op au_hnotify_op;
++
++static inline
++void au_hn_init(struct au_hinode *hinode)
++{
++	hinode->hi_notify = NULL;
++}
++
++static inline struct au_hnotify *au_hn(struct au_hinode *hinode)
++{
++	return hinode->hi_notify;
++}
++
++#else
++AuStub(int, au_hn_alloc, return -EOPNOTSUPP,
++       struct au_hinode *hinode __maybe_unused,
++       struct inode *inode __maybe_unused)
++AuStub(struct au_hnotify *, au_hn, return NULL, struct au_hinode *hinode)
++AuStubVoid(au_hn_free, struct au_hinode *hinode __maybe_unused)
++AuStubVoid(au_hn_ctl, struct au_hinode *hinode __maybe_unused,
++	   int do_set __maybe_unused)
++AuStubVoid(au_hn_reset, struct inode *inode __maybe_unused,
++	   unsigned int flags __maybe_unused)
++AuStubInt0(au_hnotify_reset_br, unsigned int udba __maybe_unused,
++	   struct au_branch *br __maybe_unused,
++	   int perm __maybe_unused)
++AuStubInt0(au_hnotify_init_br, struct au_branch *br __maybe_unused,
++	   int perm __maybe_unused)
++AuStubVoid(au_hnotify_fin_br, struct au_branch *br __maybe_unused)
++AuStubInt0(__init au_hnotify_init, void)
++AuStubVoid(au_hnotify_fin, void)
++AuStubVoid(au_hn_init, struct au_hinode *hinode __maybe_unused)
++#endif /* CONFIG_AUFS_HNOTIFY */
++
++static inline void au_hn_suspend(struct au_hinode *hdir)
++{
++	au_hn_ctl(hdir, /*do_set*/0);
++}
++
++static inline void au_hn_resume(struct au_hinode *hdir)
++{
++	au_hn_ctl(hdir, /*do_set*/1);
++}
++
++static inline void au_hn_imtx_lock(struct au_hinode *hdir)
++{
++	mutex_lock(&hdir->hi_inode->i_mutex);
++	au_hn_suspend(hdir);
++}
++
++static inline void au_hn_imtx_lock_nested(struct au_hinode *hdir,
++					  unsigned int sc __maybe_unused)
++{
++	mutex_lock_nested(&hdir->hi_inode->i_mutex, sc);
++	au_hn_suspend(hdir);
++}
++
++static inline void au_hn_imtx_unlock(struct au_hinode *hdir)
++{
++	au_hn_resume(hdir);
++	mutex_unlock(&hdir->hi_inode->i_mutex);
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_INODE_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/ioctl.c linux-4.0.4/fs/aufs/ioctl.c
+--- linux-4.0.4.orig/fs/aufs/ioctl.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/ioctl.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,206 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * ioctl
++ * plink-management and readdir in userspace.
++ * assist the pathconf(3) wrapper library.
++ * move-down
++ * File-based Hierarchical Storage Management.
++ */
++
++#include <linux/compat.h>
++#include <linux/file.h>
++#include "aufs.h"
++
++static int au_wbr_fd(struct path *path, struct aufs_wbr_fd __user *arg)
++{
++	int err, fd;
++	aufs_bindex_t wbi, bindex, bend;
++	struct file *h_file;
++	struct super_block *sb;
++	struct dentry *root;
++	struct au_branch *br;
++	struct aufs_wbr_fd wbrfd = {
++		.oflags	= au_dir_roflags,
++		.brid	= -1
++	};
++	const int valid = O_RDONLY | O_NONBLOCK | O_LARGEFILE | O_DIRECTORY
++		| O_NOATIME | O_CLOEXEC;
++
++	AuDebugOn(wbrfd.oflags & ~valid);
++
++	if (arg) {
++		err = copy_from_user(&wbrfd, arg, sizeof(wbrfd));
++		if (unlikely(err)) {
++			err = -EFAULT;
++			goto out;
++		}
++
++		err = -EINVAL;
++		AuDbg("wbrfd{0%o, %d}\n", wbrfd.oflags, wbrfd.brid);
++		wbrfd.oflags |= au_dir_roflags;
++		AuDbg("0%o\n", wbrfd.oflags);
++		if (unlikely(wbrfd.oflags & ~valid))
++			goto out;
++	}
++
++	fd = get_unused_fd_flags(0);
++	err = fd;
++	if (unlikely(fd < 0))
++		goto out;
++
++	h_file = ERR_PTR(-EINVAL);
++	wbi = 0;
++	br = NULL;
++	sb = path->dentry->d_sb;
++	root = sb->s_root;
++	aufs_read_lock(root, AuLock_IR);
++	bend = au_sbend(sb);
++	if (wbrfd.brid >= 0) {
++		wbi = au_br_index(sb, wbrfd.brid);
++		if (unlikely(wbi < 0 || wbi > bend))
++			goto out_unlock;
++	}
++
++	h_file = ERR_PTR(-ENOENT);
++	br = au_sbr(sb, wbi);
++	if (!au_br_writable(br->br_perm)) {
++		if (arg)
++			goto out_unlock;
++
++		bindex = wbi + 1;
++		wbi = -1;
++		for (; bindex <= bend; bindex++) {
++			br = au_sbr(sb, bindex);
++			if (au_br_writable(br->br_perm)) {
++				wbi = bindex;
++				br = au_sbr(sb, wbi);
++				break;
++			}
++		}
++	}
++	AuDbg("wbi %d\n", wbi);
++	if (wbi >= 0)
++		h_file = au_h_open(root, wbi, wbrfd.oflags, NULL,
++				   /*force_wr*/0);
++
++out_unlock:
++	aufs_read_unlock(root, AuLock_IR);
++	err = PTR_ERR(h_file);
++	if (IS_ERR(h_file))
++		goto out_fd;
++
++	atomic_dec(&br->br_count); /* cf. au_h_open() */
++	fd_install(fd, h_file);
++	err = fd;
++	goto out; /* success */
++
++out_fd:
++	put_unused_fd(fd);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++long aufs_ioctl_dir(struct file *file, unsigned int cmd, unsigned long arg)
++{
++	long err;
++	struct dentry *dentry;
++
++	switch (cmd) {
++	case AUFS_CTL_RDU:
++	case AUFS_CTL_RDU_INO:
++		err = au_rdu_ioctl(file, cmd, arg);
++		break;
++
++	case AUFS_CTL_WBR_FD:
++		err = au_wbr_fd(&file->f_path, (void __user *)arg);
++		break;
++
++	case AUFS_CTL_IBUSY:
++		err = au_ibusy_ioctl(file, arg);
++		break;
++
++	case AUFS_CTL_BRINFO:
++		err = au_brinfo_ioctl(file, arg);
++		break;
++
++	case AUFS_CTL_FHSM_FD:
++		dentry = file->f_path.dentry;
++		if (IS_ROOT(dentry))
++			err = au_fhsm_fd(dentry->d_sb, arg);
++		else
++			err = -ENOTTY;
++		break;
++
++	default:
++		/* do not call the lower */
++		AuDbg("0x%x\n", cmd);
++		err = -ENOTTY;
++	}
++
++	AuTraceErr(err);
++	return err;
++}
++
++long aufs_ioctl_nondir(struct file *file, unsigned int cmd, unsigned long arg)
++{
++	long err;
++
++	switch (cmd) {
++	case AUFS_CTL_MVDOWN:
++		err = au_mvdown(file->f_path.dentry, (void __user *)arg);
++		break;
++
++	case AUFS_CTL_WBR_FD:
++		err = au_wbr_fd(&file->f_path, (void __user *)arg);
++		break;
++
++	default:
++		/* do not call the lower */
++		AuDbg("0x%x\n", cmd);
++		err = -ENOTTY;
++	}
++
++	AuTraceErr(err);
++	return err;
++}
++
++#ifdef CONFIG_COMPAT
++long aufs_compat_ioctl_dir(struct file *file, unsigned int cmd,
++			   unsigned long arg)
++{
++	long err;
++
++	switch (cmd) {
++	case AUFS_CTL_RDU:
++	case AUFS_CTL_RDU_INO:
++		err = au_rdu_compat_ioctl(file, cmd, arg);
++		break;
++
++	case AUFS_CTL_IBUSY:
++		err = au_ibusy_compat_ioctl(file, arg);
++		break;
++
++	case AUFS_CTL_BRINFO:
++		err = au_brinfo_compat_ioctl(file, arg);
++		break;
++
++	default:
++		err = aufs_ioctl_dir(file, cmd, arg);
++	}
++
++	AuTraceErr(err);
++	return err;
++}
++
++long aufs_compat_ioctl_nondir(struct file *file, unsigned int cmd,
++			      unsigned long arg)
++{
++	return aufs_ioctl_nondir(file, cmd, (unsigned long)compat_ptr(arg));
++}
++#endif
+diff -Nur linux-4.0.4.orig/fs/aufs/i_op_add.c linux-4.0.4/fs/aufs/i_op_add.c
+--- linux-4.0.4.orig/fs/aufs/i_op_add.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/i_op_add.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,917 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * inode operations (add entry)
++ */
++
++#include "aufs.h"
++
++/*
++ * final procedure of adding a new entry, except link(2).
++ * remove whiteout, instantiate, copyup the parent dir's times and size
++ * and update version.
++ * if it failed, re-create the removed whiteout.
++ */
++static int epilog(struct inode *dir, aufs_bindex_t bindex,
++		  struct dentry *wh_dentry, struct dentry *dentry)
++{
++	int err, rerr;
++	aufs_bindex_t bwh;
++	struct path h_path;
++	struct super_block *sb;
++	struct inode *inode, *h_dir;
++	struct dentry *wh;
++
++	bwh = -1;
++	sb = dir->i_sb;
++	if (wh_dentry) {
++		h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
++		IMustLock(h_dir);
++		AuDebugOn(au_h_iptr(dir, bindex) != h_dir);
++		bwh = au_dbwh(dentry);
++		h_path.dentry = wh_dentry;
++		h_path.mnt = au_sbr_mnt(sb, bindex);
++		err = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path,
++					  dentry);
++		if (unlikely(err))
++			goto out;
++	}
++
++	inode = au_new_inode(dentry, /*must_new*/1);
++	if (!IS_ERR(inode)) {
++		d_instantiate(dentry, inode);
++		dir = dentry->d_parent->d_inode; /* dir inode is locked */
++		IMustLock(dir);
++		au_dir_ts(dir, bindex);
++		dir->i_version++;
++		au_fhsm_wrote(sb, bindex, /*force*/0);
++		return 0; /* success */
++	}
++
++	err = PTR_ERR(inode);
++	if (!wh_dentry)
++		goto out;
++
++	/* revert */
++	/* dir inode is locked */
++	wh = au_wh_create(dentry, bwh, wh_dentry->d_parent);
++	rerr = PTR_ERR(wh);
++	if (IS_ERR(wh)) {
++		AuIOErr("%pd reverting whiteout failed(%d, %d)\n",
++			dentry, err, rerr);
++		err = -EIO;
++	} else
++		dput(wh);
++
++out:
++	return err;
++}
++
++static int au_d_may_add(struct dentry *dentry)
++{
++	int err;
++
++	err = 0;
++	if (unlikely(d_unhashed(dentry)))
++		err = -ENOENT;
++	if (unlikely(dentry->d_inode))
++		err = -EEXIST;
++	return err;
++}
++
++/*
++ * simple tests for the adding inode operations.
++ * following the checks in vfs, plus the parent-child relationship.
++ */
++int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
++	       struct dentry *h_parent, int isdir)
++{
++	int err;
++	umode_t h_mode;
++	struct dentry *h_dentry;
++	struct inode *h_inode;
++
++	err = -ENAMETOOLONG;
++	if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
++		goto out;
++
++	h_dentry = au_h_dptr(dentry, bindex);
++	h_inode = h_dentry->d_inode;
++	if (!dentry->d_inode) {
++		err = -EEXIST;
++		if (unlikely(h_inode))
++			goto out;
++	} else {
++		/* rename(2) case */
++		err = -EIO;
++		if (unlikely(!h_inode || !h_inode->i_nlink))
++			goto out;
++
++		h_mode = h_inode->i_mode;
++		if (!isdir) {
++			err = -EISDIR;
++			if (unlikely(S_ISDIR(h_mode)))
++				goto out;
++		} else if (unlikely(!S_ISDIR(h_mode))) {
++			err = -ENOTDIR;
++			goto out;
++		}
++	}
++
++	err = 0;
++	/* expected parent dir is locked */
++	if (unlikely(h_parent != h_dentry->d_parent))
++		err = -EIO;
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/*
++ * initial procedure of adding a new entry.
++ * prepare writable branch and the parent dir, lock it,
++ * and lookup whiteout for the new entry.
++ */
++static struct dentry*
++lock_hdir_lkup_wh(struct dentry *dentry, struct au_dtime *dt,
++		  struct dentry *src_dentry, struct au_pin *pin,
++		  struct au_wr_dir_args *wr_dir_args)
++{
++	struct dentry *wh_dentry, *h_parent;
++	struct super_block *sb;
++	struct au_branch *br;
++	int err;
++	unsigned int udba;
++	aufs_bindex_t bcpup;
++
++	AuDbg("%pd\n", dentry);
++
++	err = au_wr_dir(dentry, src_dentry, wr_dir_args);
++	bcpup = err;
++	wh_dentry = ERR_PTR(err);
++	if (unlikely(err < 0))
++		goto out;
++
++	sb = dentry->d_sb;
++	udba = au_opt_udba(sb);
++	err = au_pin(pin, dentry, bcpup, udba,
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	wh_dentry = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++
++	h_parent = au_pinned_h_parent(pin);
++	if (udba != AuOpt_UDBA_NONE
++	    && au_dbstart(dentry) == bcpup)
++		err = au_may_add(dentry, bcpup, h_parent,
++				 au_ftest_wrdir(wr_dir_args->flags, ISDIR));
++	else if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
++		err = -ENAMETOOLONG;
++	wh_dentry = ERR_PTR(err);
++	if (unlikely(err))
++		goto out_unpin;
++
++	br = au_sbr(sb, bcpup);
++	if (dt) {
++		struct path tmp = {
++			.dentry	= h_parent,
++			.mnt	= au_br_mnt(br)
++		};
++		au_dtime_store(dt, au_pinned_parent(pin), &tmp);
++	}
++
++	wh_dentry = NULL;
++	if (bcpup != au_dbwh(dentry))
++		goto out; /* success */
++
++	/*
++	 * ENAMETOOLONG here means that if we allowed create such name, then it
++	 * would not be able to removed in the future. So we don't allow such
++	 * name here and we don't handle ENAMETOOLONG differently here.
++	 */
++	wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, br);
++
++out_unpin:
++	if (IS_ERR(wh_dentry))
++		au_unpin(pin);
++out:
++	return wh_dentry;
++}
++
++/* ---------------------------------------------------------------------- */
++
++enum { Mknod, Symlink, Creat };
++struct simple_arg {
++	int type;
++	union {
++		struct {
++			umode_t			mode;
++			bool			want_excl;
++			bool			try_aopen;
++			struct vfsub_aopen_args	*aopen;
++		} c;
++		struct {
++			const char *symname;
++		} s;
++		struct {
++			umode_t mode;
++			dev_t dev;
++		} m;
++	} u;
++};
++
++static int add_simple(struct inode *dir, struct dentry *dentry,
++		      struct simple_arg *arg)
++{
++	int err, rerr;
++	aufs_bindex_t bstart;
++	unsigned char created;
++	const unsigned char try_aopen
++		= (arg->type == Creat && arg->u.c.try_aopen);
++	struct dentry *wh_dentry, *parent;
++	struct inode *h_dir;
++	struct super_block *sb;
++	struct au_branch *br;
++	/* to reuduce stack size */
++	struct {
++		struct au_dtime dt;
++		struct au_pin pin;
++		struct path h_path;
++		struct au_wr_dir_args wr_dir_args;
++	} *a;
++
++	AuDbg("%pd\n", dentry);
++	IMustLock(dir);
++
++	err = -ENOMEM;
++	a = kmalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++	a->wr_dir_args.force_btgt = -1;
++	a->wr_dir_args.flags = AuWrDir_ADD_ENTRY;
++
++	parent = dentry->d_parent; /* dir inode is locked */
++	if (!try_aopen) {
++		err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
++		if (unlikely(err))
++			goto out_free;
++	}
++	err = au_d_may_add(dentry);
++	if (unlikely(err))
++		goto out_unlock;
++	if (!try_aopen)
++		di_write_lock_parent(parent);
++	wh_dentry = lock_hdir_lkup_wh(dentry, &a->dt, /*src_dentry*/NULL,
++				      &a->pin, &a->wr_dir_args);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out_parent;
++
++	bstart = au_dbstart(dentry);
++	sb = dentry->d_sb;
++	br = au_sbr(sb, bstart);
++	a->h_path.dentry = au_h_dptr(dentry, bstart);
++	a->h_path.mnt = au_br_mnt(br);
++	h_dir = au_pinned_h_dir(&a->pin);
++	switch (arg->type) {
++	case Creat:
++		err = 0;
++		if (!try_aopen || !h_dir->i_op->atomic_open)
++			err = vfsub_create(h_dir, &a->h_path, arg->u.c.mode,
++					   arg->u.c.want_excl);
++		else
++			err = vfsub_atomic_open(h_dir, a->h_path.dentry,
++						arg->u.c.aopen, br);
++		break;
++	case Symlink:
++		err = vfsub_symlink(h_dir, &a->h_path, arg->u.s.symname);
++		break;
++	case Mknod:
++		err = vfsub_mknod(h_dir, &a->h_path, arg->u.m.mode,
++				  arg->u.m.dev);
++		break;
++	default:
++		BUG();
++	}
++	created = !err;
++	if (!err)
++		err = epilog(dir, bstart, wh_dentry, dentry);
++
++	/* revert */
++	if (unlikely(created && err && a->h_path.dentry->d_inode)) {
++		/* no delegation since it is just created */
++		rerr = vfsub_unlink(h_dir, &a->h_path, /*delegated*/NULL,
++				    /*force*/0);
++		if (rerr) {
++			AuIOErr("%pd revert failure(%d, %d)\n",
++				dentry, err, rerr);
++			err = -EIO;
++		}
++		au_dtime_revert(&a->dt);
++	}
++
++	if (!err && try_aopen && !h_dir->i_op->atomic_open)
++		*arg->u.c.aopen->opened |= FILE_CREATED;
++
++	au_unpin(&a->pin);
++	dput(wh_dentry);
++
++out_parent:
++	if (!try_aopen)
++		di_write_unlock(parent);
++out_unlock:
++	if (unlikely(err)) {
++		au_update_dbstart(dentry);
++		d_drop(dentry);
++	}
++	if (!try_aopen)
++		aufs_read_unlock(dentry, AuLock_DW);
++out_free:
++	kfree(a);
++out:
++	return err;
++}
++
++int aufs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
++	       dev_t dev)
++{
++	struct simple_arg arg = {
++		.type = Mknod,
++		.u.m = {
++			.mode	= mode,
++			.dev	= dev
++		}
++	};
++	return add_simple(dir, dentry, &arg);
++}
++
++int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
++{
++	struct simple_arg arg = {
++		.type = Symlink,
++		.u.s.symname = symname
++	};
++	return add_simple(dir, dentry, &arg);
++}
++
++int aufs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
++		bool want_excl)
++{
++	struct simple_arg arg = {
++		.type = Creat,
++		.u.c = {
++			.mode		= mode,
++			.want_excl	= want_excl
++		}
++	};
++	return add_simple(dir, dentry, &arg);
++}
++
++int au_aopen_or_create(struct inode *dir, struct dentry *dentry,
++		       struct vfsub_aopen_args *aopen_args)
++{
++	struct simple_arg arg = {
++		.type = Creat,
++		.u.c = {
++			.mode		= aopen_args->create_mode,
++			.want_excl	= aopen_args->open_flag & O_EXCL,
++			.try_aopen	= true,
++			.aopen		= aopen_args
++		}
++	};
++	return add_simple(dir, dentry, &arg);
++}
++
++int aufs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
++{
++	int err;
++	aufs_bindex_t bindex;
++	struct super_block *sb;
++	struct dentry *parent, *h_parent, *h_dentry;
++	struct inode *h_dir, *inode;
++	struct vfsmount *h_mnt;
++	struct au_wr_dir_args wr_dir_args = {
++		.force_btgt	= -1,
++		.flags		= AuWrDir_TMPFILE
++	};
++
++	/* copy-up may happen */
++	mutex_lock(&dir->i_mutex);
++
++	sb = dir->i_sb;
++	err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++	if (unlikely(err))
++		goto out;
++
++	err = au_di_init(dentry);
++	if (unlikely(err))
++		goto out_si;
++
++	err = -EBUSY;
++	parent = d_find_any_alias(dir);
++	AuDebugOn(!parent);
++	di_write_lock_parent(parent);
++	if (unlikely(parent->d_inode != dir))
++		goto out_parent;
++
++	err = au_digen_test(parent, au_sigen(sb));
++	if (unlikely(err))
++		goto out_parent;
++
++	bindex = au_dbstart(parent);
++	au_set_dbstart(dentry, bindex);
++	au_set_dbend(dentry, bindex);
++	err = au_wr_dir(dentry, /*src_dentry*/NULL, &wr_dir_args);
++	bindex = err;
++	if (unlikely(err < 0))
++		goto out_parent;
++
++	err = -EOPNOTSUPP;
++	h_dir = au_h_iptr(dir, bindex);
++	if (unlikely(!h_dir->i_op->tmpfile))
++		goto out_parent;
++
++	h_mnt = au_sbr_mnt(sb, bindex);
++	err = vfsub_mnt_want_write(h_mnt);
++	if (unlikely(err))
++		goto out_parent;
++
++	h_parent = au_h_dptr(parent, bindex);
++	err = inode_permission(h_parent->d_inode, MAY_WRITE | MAY_EXEC);
++	if (unlikely(err))
++		goto out_mnt;
++
++	err = -ENOMEM;
++	h_dentry = d_alloc(h_parent, &dentry->d_name);
++	if (unlikely(!h_dentry))
++		goto out_mnt;
++
++	err = h_dir->i_op->tmpfile(h_dir, h_dentry, mode);
++	if (unlikely(err))
++		goto out_dentry;
++
++	au_set_dbstart(dentry, bindex);
++	au_set_dbend(dentry, bindex);
++	au_set_h_dptr(dentry, bindex, dget(h_dentry));
++	inode = au_new_inode(dentry, /*must_new*/1);
++	if (IS_ERR(inode)) {
++		err = PTR_ERR(inode);
++		au_set_h_dptr(dentry, bindex, NULL);
++		au_set_dbstart(dentry, -1);
++		au_set_dbend(dentry, -1);
++	} else {
++		if (!inode->i_nlink)
++			set_nlink(inode, 1);
++		d_tmpfile(dentry, inode);
++		au_di(dentry)->di_tmpfile = 1;
++
++		/* update without i_mutex */
++		if (au_ibstart(dir) == au_dbstart(dentry))
++			au_cpup_attr_timesizes(dir);
++	}
++
++out_dentry:
++	dput(h_dentry);
++out_mnt:
++	vfsub_mnt_drop_write(h_mnt);
++out_parent:
++	di_write_unlock(parent);
++	dput(parent);
++	di_write_unlock(dentry);
++	if (!err)
++#if 0
++		/* verbose coding for lock class name */
++		au_rw_class(&au_di(dentry)->di_rwsem,
++			    au_lc_key + AuLcNonDir_DIINFO);
++#else
++		;
++#endif
++	else {
++		au_di_fin(dentry);
++		dentry->d_fsdata = NULL;
++	}
++out_si:
++	si_read_unlock(sb);
++out:
++	mutex_unlock(&dir->i_mutex);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_link_args {
++	aufs_bindex_t bdst, bsrc;
++	struct au_pin pin;
++	struct path h_path;
++	struct dentry *src_parent, *parent;
++};
++
++static int au_cpup_before_link(struct dentry *src_dentry,
++			       struct au_link_args *a)
++{
++	int err;
++	struct dentry *h_src_dentry;
++	struct au_cp_generic cpg = {
++		.dentry	= src_dentry,
++		.bdst	= a->bdst,
++		.bsrc	= a->bsrc,
++		.len	= -1,
++		.pin	= &a->pin,
++		.flags	= AuCpup_DTIME | AuCpup_HOPEN /* | AuCpup_KEEPLINO */
++	};
++
++	di_read_lock_parent(a->src_parent, AuLock_IR);
++	err = au_test_and_cpup_dirs(src_dentry, a->bdst);
++	if (unlikely(err))
++		goto out;
++
++	h_src_dentry = au_h_dptr(src_dentry, a->bsrc);
++	err = au_pin(&a->pin, src_dentry, a->bdst,
++		     au_opt_udba(src_dentry->d_sb),
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	if (unlikely(err))
++		goto out;
++
++	err = au_sio_cpup_simple(&cpg);
++	au_unpin(&a->pin);
++
++out:
++	di_read_unlock(a->src_parent, AuLock_IR);
++	return err;
++}
++
++static int au_cpup_or_link(struct dentry *src_dentry, struct dentry *dentry,
++			   struct au_link_args *a)
++{
++	int err;
++	unsigned char plink;
++	aufs_bindex_t bend;
++	struct dentry *h_src_dentry;
++	struct inode *h_inode, *inode, *delegated;
++	struct super_block *sb;
++	struct file *h_file;
++
++	plink = 0;
++	h_inode = NULL;
++	sb = src_dentry->d_sb;
++	inode = src_dentry->d_inode;
++	if (au_ibstart(inode) <= a->bdst)
++		h_inode = au_h_iptr(inode, a->bdst);
++	if (!h_inode || !h_inode->i_nlink) {
++		/* copyup src_dentry as the name of dentry. */
++		bend = au_dbend(dentry);
++		if (bend < a->bsrc)
++			au_set_dbend(dentry, a->bsrc);
++		au_set_h_dptr(dentry, a->bsrc,
++			      dget(au_h_dptr(src_dentry, a->bsrc)));
++		dget(a->h_path.dentry);
++		au_set_h_dptr(dentry, a->bdst, NULL);
++		AuDbg("temporary d_inode...\n");
++		spin_lock(&dentry->d_lock);
++		dentry->d_inode = src_dentry->d_inode; /* tmp */
++		spin_unlock(&dentry->d_lock);
++		h_file = au_h_open_pre(dentry, a->bsrc, /*force_wr*/0);
++		if (IS_ERR(h_file))
++			err = PTR_ERR(h_file);
++		else {
++			struct au_cp_generic cpg = {
++				.dentry	= dentry,
++				.bdst	= a->bdst,
++				.bsrc	= -1,
++				.len	= -1,
++				.pin	= &a->pin,
++				.flags	= AuCpup_KEEPLINO
++			};
++			err = au_sio_cpup_simple(&cpg);
++			au_h_open_post(dentry, a->bsrc, h_file);
++			if (!err) {
++				dput(a->h_path.dentry);
++				a->h_path.dentry = au_h_dptr(dentry, a->bdst);
++			} else
++				au_set_h_dptr(dentry, a->bdst,
++					      a->h_path.dentry);
++		}
++		spin_lock(&dentry->d_lock);
++		dentry->d_inode = NULL; /* restore */
++		spin_unlock(&dentry->d_lock);
++		AuDbg("temporary d_inode...done\n");
++		au_set_h_dptr(dentry, a->bsrc, NULL);
++		au_set_dbend(dentry, bend);
++	} else {
++		/* the inode of src_dentry already exists on a.bdst branch */
++		h_src_dentry = d_find_alias(h_inode);
++		if (!h_src_dentry && au_plink_test(inode)) {
++			plink = 1;
++			h_src_dentry = au_plink_lkup(inode, a->bdst);
++			err = PTR_ERR(h_src_dentry);
++			if (IS_ERR(h_src_dentry))
++				goto out;
++
++			if (unlikely(!h_src_dentry->d_inode)) {
++				dput(h_src_dentry);
++				h_src_dentry = NULL;
++			}
++
++		}
++		if (h_src_dentry) {
++			delegated = NULL;
++			err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
++					 &a->h_path, &delegated);
++			if (unlikely(err == -EWOULDBLOCK)) {
++				pr_warn("cannot retry for NFSv4 delegation"
++					" for an internal link\n");
++				iput(delegated);
++			}
++			dput(h_src_dentry);
++		} else {
++			AuIOErr("no dentry found for hi%lu on b%d\n",
++				h_inode->i_ino, a->bdst);
++			err = -EIO;
++		}
++	}
++
++	if (!err && !plink)
++		au_plink_append(inode, a->bdst, a->h_path.dentry);
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++int aufs_link(struct dentry *src_dentry, struct inode *dir,
++	      struct dentry *dentry)
++{
++	int err, rerr;
++	struct au_dtime dt;
++	struct au_link_args *a;
++	struct dentry *wh_dentry, *h_src_dentry;
++	struct inode *inode, *delegated;
++	struct super_block *sb;
++	struct au_wr_dir_args wr_dir_args = {
++		/* .force_btgt	= -1, */
++		.flags		= AuWrDir_ADD_ENTRY
++	};
++
++	IMustLock(dir);
++	inode = src_dentry->d_inode;
++	IMustLock(inode);
++
++	err = -ENOMEM;
++	a = kzalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	a->parent = dentry->d_parent; /* dir inode is locked */
++	err = aufs_read_and_write_lock2(dentry, src_dentry,
++					AuLock_NOPLM | AuLock_GEN);
++	if (unlikely(err))
++		goto out_kfree;
++	err = au_d_linkable(src_dentry);
++	if (unlikely(err))
++		goto out_unlock;
++	err = au_d_may_add(dentry);
++	if (unlikely(err))
++		goto out_unlock;
++
++	a->src_parent = dget_parent(src_dentry);
++	wr_dir_args.force_btgt = au_ibstart(inode);
++
++	di_write_lock_parent(a->parent);
++	wr_dir_args.force_btgt = au_wbr(dentry, wr_dir_args.force_btgt);
++	wh_dentry = lock_hdir_lkup_wh(dentry, &dt, src_dentry, &a->pin,
++				      &wr_dir_args);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out_parent;
++
++	err = 0;
++	sb = dentry->d_sb;
++	a->bdst = au_dbstart(dentry);
++	a->h_path.dentry = au_h_dptr(dentry, a->bdst);
++	a->h_path.mnt = au_sbr_mnt(sb, a->bdst);
++	a->bsrc = au_ibstart(inode);
++	h_src_dentry = au_h_d_alias(src_dentry, a->bsrc);
++	if (!h_src_dentry && au_di(src_dentry)->di_tmpfile)
++		h_src_dentry = dget(au_hi_wh(inode, a->bsrc));
++	if (!h_src_dentry) {
++		a->bsrc = au_dbstart(src_dentry);
++		h_src_dentry = au_h_d_alias(src_dentry, a->bsrc);
++		AuDebugOn(!h_src_dentry);
++	} else if (IS_ERR(h_src_dentry)) {
++		err = PTR_ERR(h_src_dentry);
++		goto out_parent;
++	}
++
++	if (au_opt_test(au_mntflags(sb), PLINK)) {
++		if (a->bdst < a->bsrc
++		    /* && h_src_dentry->d_sb != a->h_path.dentry->d_sb */)
++			err = au_cpup_or_link(src_dentry, dentry, a);
++		else {
++			delegated = NULL;
++			err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
++					 &a->h_path, &delegated);
++			if (unlikely(err == -EWOULDBLOCK)) {
++				pr_warn("cannot retry for NFSv4 delegation"
++					" for an internal link\n");
++				iput(delegated);
++			}
++		}
++		dput(h_src_dentry);
++	} else {
++		/*
++		 * copyup src_dentry to the branch we process,
++		 * and then link(2) to it.
++		 */
++		dput(h_src_dentry);
++		if (a->bdst < a->bsrc
++		    /* && h_src_dentry->d_sb != a->h_path.dentry->d_sb */) {
++			au_unpin(&a->pin);
++			di_write_unlock(a->parent);
++			err = au_cpup_before_link(src_dentry, a);
++			di_write_lock_parent(a->parent);
++			if (!err)
++				err = au_pin(&a->pin, dentry, a->bdst,
++					     au_opt_udba(sb),
++					     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++			if (unlikely(err))
++				goto out_wh;
++		}
++		if (!err) {
++			h_src_dentry = au_h_dptr(src_dentry, a->bdst);
++			err = -ENOENT;
++			if (h_src_dentry && h_src_dentry->d_inode) {
++				delegated = NULL;
++				err = vfsub_link(h_src_dentry,
++						 au_pinned_h_dir(&a->pin),
++						 &a->h_path, &delegated);
++				if (unlikely(err == -EWOULDBLOCK)) {
++					pr_warn("cannot retry"
++						" for NFSv4 delegation"
++						" for an internal link\n");
++					iput(delegated);
++				}
++			}
++		}
++	}
++	if (unlikely(err))
++		goto out_unpin;
++
++	if (wh_dentry) {
++		a->h_path.dentry = wh_dentry;
++		err = au_wh_unlink_dentry(au_pinned_h_dir(&a->pin), &a->h_path,
++					  dentry);
++		if (unlikely(err))
++			goto out_revert;
++	}
++
++	au_dir_ts(dir, a->bdst);
++	dir->i_version++;
++	inc_nlink(inode);
++	inode->i_ctime = dir->i_ctime;
++	d_instantiate(dentry, au_igrab(inode));
++	if (d_unhashed(a->h_path.dentry))
++		/* some filesystem calls d_drop() */
++		d_drop(dentry);
++	/* some filesystems consume an inode even hardlink */
++	au_fhsm_wrote(sb, a->bdst, /*force*/0);
++	goto out_unpin; /* success */
++
++out_revert:
++	/* no delegation since it is just created */
++	rerr = vfsub_unlink(au_pinned_h_dir(&a->pin), &a->h_path,
++			    /*delegated*/NULL, /*force*/0);
++	if (unlikely(rerr)) {
++		AuIOErr("%pd reverting failed(%d, %d)\n", dentry, err, rerr);
++		err = -EIO;
++	}
++	au_dtime_revert(&dt);
++out_unpin:
++	au_unpin(&a->pin);
++out_wh:
++	dput(wh_dentry);
++out_parent:
++	di_write_unlock(a->parent);
++	dput(a->src_parent);
++out_unlock:
++	if (unlikely(err)) {
++		au_update_dbstart(dentry);
++		d_drop(dentry);
++	}
++	aufs_read_and_write_unlock2(dentry, src_dentry);
++out_kfree:
++	kfree(a);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++int aufs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
++{
++	int err, rerr;
++	aufs_bindex_t bindex;
++	unsigned char diropq;
++	struct path h_path;
++	struct dentry *wh_dentry, *parent, *opq_dentry;
++	struct mutex *h_mtx;
++	struct super_block *sb;
++	struct {
++		struct au_pin pin;
++		struct au_dtime dt;
++	} *a; /* reduce the stack usage */
++	struct au_wr_dir_args wr_dir_args = {
++		.force_btgt	= -1,
++		.flags		= AuWrDir_ADD_ENTRY | AuWrDir_ISDIR
++	};
++
++	IMustLock(dir);
++
++	err = -ENOMEM;
++	a = kmalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
++	if (unlikely(err))
++		goto out_free;
++	err = au_d_may_add(dentry);
++	if (unlikely(err))
++		goto out_unlock;
++
++	parent = dentry->d_parent; /* dir inode is locked */
++	di_write_lock_parent(parent);
++	wh_dentry = lock_hdir_lkup_wh(dentry, &a->dt, /*src_dentry*/NULL,
++				      &a->pin, &wr_dir_args);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out_parent;
++
++	sb = dentry->d_sb;
++	bindex = au_dbstart(dentry);
++	h_path.dentry = au_h_dptr(dentry, bindex);
++	h_path.mnt = au_sbr_mnt(sb, bindex);
++	err = vfsub_mkdir(au_pinned_h_dir(&a->pin), &h_path, mode);
++	if (unlikely(err))
++		goto out_unpin;
++
++	/* make the dir opaque */
++	diropq = 0;
++	h_mtx = &h_path.dentry->d_inode->i_mutex;
++	if (wh_dentry
++	    || au_opt_test(au_mntflags(sb), ALWAYS_DIROPQ)) {
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		opq_dentry = au_diropq_create(dentry, bindex);
++		mutex_unlock(h_mtx);
++		err = PTR_ERR(opq_dentry);
++		if (IS_ERR(opq_dentry))
++			goto out_dir;
++		dput(opq_dentry);
++		diropq = 1;
++	}
++
++	err = epilog(dir, bindex, wh_dentry, dentry);
++	if (!err) {
++		inc_nlink(dir);
++		goto out_unpin; /* success */
++	}
++
++	/* revert */
++	if (diropq) {
++		AuLabel(revert opq);
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		rerr = au_diropq_remove(dentry, bindex);
++		mutex_unlock(h_mtx);
++		if (rerr) {
++			AuIOErr("%pd reverting diropq failed(%d, %d)\n",
++				dentry, err, rerr);
++			err = -EIO;
++		}
++	}
++
++out_dir:
++	AuLabel(revert dir);
++	rerr = vfsub_rmdir(au_pinned_h_dir(&a->pin), &h_path);
++	if (rerr) {
++		AuIOErr("%pd reverting dir failed(%d, %d)\n",
++			dentry, err, rerr);
++		err = -EIO;
++	}
++	au_dtime_revert(&a->dt);
++out_unpin:
++	au_unpin(&a->pin);
++	dput(wh_dentry);
++out_parent:
++	di_write_unlock(parent);
++out_unlock:
++	if (unlikely(err)) {
++		au_update_dbstart(dentry);
++		d_drop(dentry);
++	}
++	aufs_read_unlock(dentry, AuLock_DW);
++out_free:
++	kfree(a);
++out:
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/i_op.c linux-4.0.4/fs/aufs/i_op.c
+--- linux-4.0.4.orig/fs/aufs/i_op.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/i_op.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,1432 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * inode operations (except add/del/rename)
++ */
++
++#include <linux/device_cgroup.h>
++#include <linux/fs_stack.h>
++#include <linux/mm.h>
++#include <linux/namei.h>
++#include <linux/security.h>
++#include "aufs.h"
++
++static int h_permission(struct inode *h_inode, int mask,
++			struct vfsmount *h_mnt, int brperm)
++{
++	int err;
++	const unsigned char write_mask = !!(mask & (MAY_WRITE | MAY_APPEND));
++
++	err = -EACCES;
++	if ((write_mask && IS_IMMUTABLE(h_inode))
++	    || ((mask & MAY_EXEC)
++		&& S_ISREG(h_inode->i_mode)
++		&& ((h_mnt->mnt_flags & MNT_NOEXEC)
++		    || !(h_inode->i_mode & S_IXUGO))))
++		goto out;
++
++	/*
++	 * - skip the lower fs test in the case of write to ro branch.
++	 * - nfs dir permission write check is optimized, but a policy for
++	 *   link/rename requires a real check.
++	 * - nfs always sets MS_POSIXACL regardless its mount option 'noacl.'
++	 *   in this case, generic_permission() returns -EOPNOTSUPP.
++	 */
++	if ((write_mask && !au_br_writable(brperm))
++	    || (au_test_nfs(h_inode->i_sb) && S_ISDIR(h_inode->i_mode)
++		&& write_mask && !(mask & MAY_READ))
++	    || !h_inode->i_op->permission) {
++		/* AuLabel(generic_permission); */
++		/* AuDbg("get_acl %pf\n", h_inode->i_op->get_acl); */
++		err = generic_permission(h_inode, mask);
++		if (err == -EOPNOTSUPP && au_test_nfs_noacl(h_inode))
++			err = h_inode->i_op->permission(h_inode, mask);
++		AuTraceErr(err);
++	} else {
++		/* AuLabel(h_inode->permission); */
++		err = h_inode->i_op->permission(h_inode, mask);
++		AuTraceErr(err);
++	}
++
++	if (!err)
++		err = devcgroup_inode_permission(h_inode, mask);
++	if (!err)
++		err = security_inode_permission(h_inode, mask);
++
++#if 0
++	if (!err) {
++		/* todo: do we need to call ima_path_check()? */
++		struct path h_path = {
++			.dentry	=
++			.mnt	= h_mnt
++		};
++		err = ima_path_check(&h_path,
++				     mask & (MAY_READ | MAY_WRITE | MAY_EXEC),
++				     IMA_COUNT_LEAVE);
++	}
++#endif
++
++out:
++	return err;
++}
++
++static int aufs_permission(struct inode *inode, int mask)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	const unsigned char isdir = !!S_ISDIR(inode->i_mode),
++		write_mask = !!(mask & (MAY_WRITE | MAY_APPEND));
++	struct inode *h_inode;
++	struct super_block *sb;
++	struct au_branch *br;
++
++	/* todo: support rcu-walk? */
++	if (mask & MAY_NOT_BLOCK)
++		return -ECHILD;
++
++	sb = inode->i_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	ii_read_lock_child(inode);
++#if 0
++	err = au_iigen_test(inode, au_sigen(sb));
++	if (unlikely(err))
++		goto out;
++#endif
++
++	if (!isdir
++	    || write_mask
++	    || au_opt_test(au_mntflags(sb), DIRPERM1)) {
++		err = au_busy_or_stale();
++		h_inode = au_h_iptr(inode, au_ibstart(inode));
++		if (unlikely(!h_inode
++			     || (h_inode->i_mode & S_IFMT)
++			     != (inode->i_mode & S_IFMT)))
++			goto out;
++
++		err = 0;
++		bindex = au_ibstart(inode);
++		br = au_sbr(sb, bindex);
++		err = h_permission(h_inode, mask, au_br_mnt(br), br->br_perm);
++		if (write_mask
++		    && !err
++		    && !special_file(h_inode->i_mode)) {
++			/* test whether the upper writable branch exists */
++			err = -EROFS;
++			for (; bindex >= 0; bindex--)
++				if (!au_br_rdonly(au_sbr(sb, bindex))) {
++					err = 0;
++					break;
++				}
++		}
++		goto out;
++	}
++
++	/* non-write to dir */
++	err = 0;
++	bend = au_ibend(inode);
++	for (bindex = au_ibstart(inode); !err && bindex <= bend; bindex++) {
++		h_inode = au_h_iptr(inode, bindex);
++		if (h_inode) {
++			err = au_busy_or_stale();
++			if (unlikely(!S_ISDIR(h_inode->i_mode)))
++				break;
++
++			br = au_sbr(sb, bindex);
++			err = h_permission(h_inode, mask, au_br_mnt(br),
++					   br->br_perm);
++		}
++	}
++
++out:
++	ii_read_unlock(inode);
++	si_read_unlock(sb);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct dentry *aufs_lookup(struct inode *dir, struct dentry *dentry,
++				  unsigned int flags)
++{
++	struct dentry *ret, *parent;
++	struct inode *inode;
++	struct super_block *sb;
++	int err, npositive;
++
++	IMustLock(dir);
++
++	/* todo: support rcu-walk? */
++	ret = ERR_PTR(-ECHILD);
++	if (flags & LOOKUP_RCU)
++		goto out;
++
++	ret = ERR_PTR(-ENAMETOOLONG);
++	if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
++		goto out;
++
++	sb = dir->i_sb;
++	err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++	ret = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++
++	err = au_di_init(dentry);
++	ret = ERR_PTR(err);
++	if (unlikely(err))
++		goto out_si;
++
++	inode = NULL;
++	npositive = 0; /* suppress a warning */
++	parent = dentry->d_parent; /* dir inode is locked */
++	di_read_lock_parent(parent, AuLock_IR);
++	err = au_alive_dir(parent);
++	if (!err)
++		err = au_digen_test(parent, au_sigen(sb));
++	if (!err) {
++		npositive = au_lkup_dentry(dentry, au_dbstart(parent),
++					   /*type*/0);
++		err = npositive;
++	}
++	di_read_unlock(parent, AuLock_IR);
++	ret = ERR_PTR(err);
++	if (unlikely(err < 0))
++		goto out_unlock;
++
++	if (npositive) {
++		inode = au_new_inode(dentry, /*must_new*/0);
++		if (IS_ERR(inode)) {
++			ret = (void *)inode;
++			inode = NULL;
++			goto out_unlock;
++		}
++	}
++
++	if (inode)
++		atomic_inc(&inode->i_count);
++	ret = d_splice_alias(inode, dentry);
++#if 0
++	if (unlikely(d_need_lookup(dentry))) {
++		spin_lock(&dentry->d_lock);
++		dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
++		spin_unlock(&dentry->d_lock);
++	} else
++#endif
++	if (inode) {
++		if (!IS_ERR(ret)) {
++			iput(inode);
++			if (ret && ret != dentry)
++				ii_write_unlock(inode);
++		} else {
++			ii_write_unlock(inode);
++			iput(inode);
++			inode = NULL;
++		}
++	}
++
++out_unlock:
++	di_write_unlock(dentry);
++	if (inode) {
++		/* verbose coding for lock class name */
++		if (unlikely(S_ISLNK(inode->i_mode)))
++			au_rw_class(&au_di(dentry)->di_rwsem,
++				    au_lc_key + AuLcSymlink_DIINFO);
++		else if (unlikely(S_ISDIR(inode->i_mode)))
++			au_rw_class(&au_di(dentry)->di_rwsem,
++				    au_lc_key + AuLcDir_DIINFO);
++		else /* likely */
++			au_rw_class(&au_di(dentry)->di_rwsem,
++				    au_lc_key + AuLcNonDir_DIINFO);
++	}
++out_si:
++	si_read_unlock(sb);
++out:
++	return ret;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct aopen_node {
++	struct hlist_node hlist;
++	struct file *file, *h_file;
++};
++
++static int au_do_aopen(struct inode *inode, struct file *file)
++{
++	struct au_sphlhead *aopen;
++	struct aopen_node *node;
++	struct au_do_open_args args = {
++		.no_lock	= 1,
++		.open		= au_do_open_nondir
++	};
++
++	aopen = &au_sbi(inode->i_sb)->si_aopen;
++	spin_lock(&aopen->spin);
++	hlist_for_each_entry(node, &aopen->head, hlist)
++		if (node->file == file) {
++			args.h_file = node->h_file;
++			break;
++		}
++	spin_unlock(&aopen->spin);
++	/* AuDebugOn(!args.h_file); */
++
++	return au_do_open(file, &args);
++}
++
++static int aufs_atomic_open(struct inode *dir, struct dentry *dentry,
++			    struct file *file, unsigned int open_flag,
++			    umode_t create_mode, int *opened)
++{
++	int err, h_opened = *opened;
++	struct dentry *parent;
++	struct dentry *d;
++	struct au_sphlhead *aopen;
++	struct vfsub_aopen_args args = {
++		.open_flag	= open_flag,
++		.create_mode	= create_mode,
++		.opened		= &h_opened
++	};
++	struct aopen_node aopen_node = {
++		.file	= file
++	};
++
++	IMustLock(dir);
++	AuDbg("open_flag 0x%x\n", open_flag);
++	AuDbgDentry(dentry);
++
++	err = 0;
++	if (!au_di(dentry)) {
++		d = aufs_lookup(dir, dentry, /*flags*/0);
++		if (IS_ERR(d)) {
++			err = PTR_ERR(d);
++			goto out;
++		} else if (d) {
++			/*
++			 * obsoleted dentry found.
++			 * another error will be returned later.
++			 */
++			d_drop(d);
++			dput(d);
++			AuDbgDentry(d);
++		}
++		AuDbgDentry(dentry);
++	}
++
++	if (d_is_positive(dentry)
++	    || d_unhashed(dentry)
++	    || d_unlinked(dentry)
++	    || !(open_flag & O_CREAT))
++		goto out_no_open;
++
++	err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH | AuLock_GEN);
++	if (unlikely(err))
++		goto out;
++
++	parent = dentry->d_parent;	/* dir is locked */
++	di_write_lock_parent(parent);
++	err = au_lkup_dentry(dentry, /*bstart*/0, /*type*/0);
++	if (unlikely(err))
++		goto out_unlock;
++
++	AuDbgDentry(dentry);
++	if (d_is_positive(dentry))
++		goto out_unlock;
++
++	args.file = get_empty_filp();
++	err = PTR_ERR(args.file);
++	if (IS_ERR(args.file))
++		goto out_unlock;
++
++	args.file->f_flags = file->f_flags;
++	err = au_aopen_or_create(dir, dentry, &args);
++	AuTraceErr(err);
++	AuDbgFile(args.file);
++	if (unlikely(err < 0)) {
++		if (h_opened & FILE_OPENED)
++			fput(args.file);
++		else
++			put_filp(args.file);
++		goto out_unlock;
++	}
++
++	/* some filesystems don't set FILE_CREATED while succeeded? */
++	*opened |= FILE_CREATED;
++	if (h_opened & FILE_OPENED)
++		aopen_node.h_file = args.file;
++	else {
++		put_filp(args.file);
++		args.file = NULL;
++	}
++	aopen = &au_sbi(dir->i_sb)->si_aopen;
++	au_sphl_add(&aopen_node.hlist, aopen);
++	err = finish_open(file, dentry, au_do_aopen, opened);
++	au_sphl_del(&aopen_node.hlist, aopen);
++	AuTraceErr(err);
++	AuDbgFile(file);
++	if (aopen_node.h_file)
++		fput(aopen_node.h_file);
++
++out_unlock:
++	di_write_unlock(parent);
++	aufs_read_unlock(dentry, AuLock_DW);
++	AuDbgDentry(dentry);
++	if (unlikely(err))
++		goto out;
++out_no_open:
++	if (!err && !(*opened & FILE_CREATED)) {
++		AuLabel(out_no_open);
++		dget(dentry);
++		err = finish_no_open(file, dentry);
++	}
++out:
++	AuDbg("%pd%s%s\n", dentry,
++	      (*opened & FILE_CREATED) ? " created" : "",
++	      (*opened & FILE_OPENED) ? " opened" : "");
++	AuTraceErr(err);
++	return err;
++}
++
++
++/* ---------------------------------------------------------------------- */
++
++static int au_wr_dir_cpup(struct dentry *dentry, struct dentry *parent,
++			  const unsigned char add_entry, aufs_bindex_t bcpup,
++			  aufs_bindex_t bstart)
++{
++	int err;
++	struct dentry *h_parent;
++	struct inode *h_dir;
++
++	if (add_entry)
++		IMustLock(parent->d_inode);
++	else
++		di_write_lock_parent(parent);
++
++	err = 0;
++	if (!au_h_dptr(parent, bcpup)) {
++		if (bstart > bcpup)
++			err = au_cpup_dirs(dentry, bcpup);
++		else if (bstart < bcpup)
++			err = au_cpdown_dirs(dentry, bcpup);
++		else
++			BUG();
++	}
++	if (!err && add_entry && !au_ftest_wrdir(add_entry, TMPFILE)) {
++		h_parent = au_h_dptr(parent, bcpup);
++		h_dir = h_parent->d_inode;
++		mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
++		err = au_lkup_neg(dentry, bcpup, /*wh*/0);
++		/* todo: no unlock here */
++		mutex_unlock(&h_dir->i_mutex);
++
++		AuDbg("bcpup %d\n", bcpup);
++		if (!err) {
++			if (!dentry->d_inode)
++				au_set_h_dptr(dentry, bstart, NULL);
++			au_update_dbrange(dentry, /*do_put_zero*/0);
++		}
++	}
++
++	if (!add_entry)
++		di_write_unlock(parent);
++	if (!err)
++		err = bcpup; /* success */
++
++	AuTraceErr(err);
++	return err;
++}
++
++/*
++ * decide the branch and the parent dir where we will create a new entry.
++ * returns new bindex or an error.
++ * copyup the parent dir if needed.
++ */
++int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
++	      struct au_wr_dir_args *args)
++{
++	int err;
++	unsigned int flags;
++	aufs_bindex_t bcpup, bstart, src_bstart;
++	const unsigned char add_entry
++		= au_ftest_wrdir(args->flags, ADD_ENTRY)
++		| au_ftest_wrdir(args->flags, TMPFILE);
++	struct super_block *sb;
++	struct dentry *parent;
++	struct au_sbinfo *sbinfo;
++
++	sb = dentry->d_sb;
++	sbinfo = au_sbi(sb);
++	parent = dget_parent(dentry);
++	bstart = au_dbstart(dentry);
++	bcpup = bstart;
++	if (args->force_btgt < 0) {
++		if (src_dentry) {
++			src_bstart = au_dbstart(src_dentry);
++			if (src_bstart < bstart)
++				bcpup = src_bstart;
++		} else if (add_entry) {
++			flags = 0;
++			if (au_ftest_wrdir(args->flags, ISDIR))
++				au_fset_wbr(flags, DIR);
++			err = AuWbrCreate(sbinfo, dentry, flags);
++			bcpup = err;
++		}
++
++		if (bcpup < 0 || au_test_ro(sb, bcpup, dentry->d_inode)) {
++			if (add_entry)
++				err = AuWbrCopyup(sbinfo, dentry);
++			else {
++				if (!IS_ROOT(dentry)) {
++					di_read_lock_parent(parent, !AuLock_IR);
++					err = AuWbrCopyup(sbinfo, dentry);
++					di_read_unlock(parent, !AuLock_IR);
++				} else
++					err = AuWbrCopyup(sbinfo, dentry);
++			}
++			bcpup = err;
++			if (unlikely(err < 0))
++				goto out;
++		}
++	} else {
++		bcpup = args->force_btgt;
++		AuDebugOn(au_test_ro(sb, bcpup, dentry->d_inode));
++	}
++
++	AuDbg("bstart %d, bcpup %d\n", bstart, bcpup);
++	err = bcpup;
++	if (bcpup == bstart)
++		goto out; /* success */
++
++	/* copyup the new parent into the branch we process */
++	err = au_wr_dir_cpup(dentry, parent, add_entry, bcpup, bstart);
++	if (err >= 0) {
++		if (!dentry->d_inode) {
++			au_set_h_dptr(dentry, bstart, NULL);
++			au_set_dbstart(dentry, bcpup);
++			au_set_dbend(dentry, bcpup);
++		}
++		AuDebugOn(add_entry
++			  && !au_ftest_wrdir(args->flags, TMPFILE)
++			  && !au_h_dptr(dentry, bcpup));
++	}
++
++out:
++	dput(parent);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_pin_hdir_unlock(struct au_pin *p)
++{
++	if (p->hdir)
++		au_hn_imtx_unlock(p->hdir);
++}
++
++int au_pin_hdir_lock(struct au_pin *p)
++{
++	int err;
++
++	err = 0;
++	if (!p->hdir)
++		goto out;
++
++	/* even if an error happens later, keep this lock */
++	au_hn_imtx_lock_nested(p->hdir, p->lsc_hi);
++
++	err = -EBUSY;
++	if (unlikely(p->hdir->hi_inode != p->h_parent->d_inode))
++		goto out;
++
++	err = 0;
++	if (p->h_dentry)
++		err = au_h_verify(p->h_dentry, p->udba, p->hdir->hi_inode,
++				  p->h_parent, p->br);
++
++out:
++	return err;
++}
++
++int au_pin_hdir_relock(struct au_pin *p)
++{
++	int err, i;
++	struct inode *h_i;
++	struct dentry *h_d[] = {
++		p->h_dentry,
++		p->h_parent
++	};
++
++	err = au_pin_hdir_lock(p);
++	if (unlikely(err))
++		goto out;
++
++	for (i = 0; !err && i < sizeof(h_d)/sizeof(*h_d); i++) {
++		if (!h_d[i])
++			continue;
++		h_i = h_d[i]->d_inode;
++		if (h_i)
++			err = !h_i->i_nlink;
++	}
++
++out:
++	return err;
++}
++
++void au_pin_hdir_set_owner(struct au_pin *p, struct task_struct *task)
++{
++#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP)
++	p->hdir->hi_inode->i_mutex.owner = task;
++#endif
++}
++
++void au_pin_hdir_acquire_nest(struct au_pin *p)
++{
++	if (p->hdir) {
++		mutex_acquire_nest(&p->hdir->hi_inode->i_mutex.dep_map,
++				   p->lsc_hi, 0, NULL, _RET_IP_);
++		au_pin_hdir_set_owner(p, current);
++	}
++}
++
++void au_pin_hdir_release(struct au_pin *p)
++{
++	if (p->hdir) {
++		au_pin_hdir_set_owner(p, p->task);
++		mutex_release(&p->hdir->hi_inode->i_mutex.dep_map, 1, _RET_IP_);
++	}
++}
++
++struct dentry *au_pinned_h_parent(struct au_pin *pin)
++{
++	if (pin && pin->parent)
++		return au_h_dptr(pin->parent, pin->bindex);
++	return NULL;
++}
++
++void au_unpin(struct au_pin *p)
++{
++	if (p->hdir)
++		au_pin_hdir_unlock(p);
++	if (p->h_mnt && au_ftest_pin(p->flags, MNT_WRITE))
++		vfsub_mnt_drop_write(p->h_mnt);
++	if (!p->hdir)
++		return;
++
++	if (!au_ftest_pin(p->flags, DI_LOCKED))
++		di_read_unlock(p->parent, AuLock_IR);
++	iput(p->hdir->hi_inode);
++	dput(p->parent);
++	p->parent = NULL;
++	p->hdir = NULL;
++	p->h_mnt = NULL;
++	/* do not clear p->task */
++}
++
++int au_do_pin(struct au_pin *p)
++{
++	int err;
++	struct super_block *sb;
++	struct inode *h_dir;
++
++	err = 0;
++	sb = p->dentry->d_sb;
++	p->br = au_sbr(sb, p->bindex);
++	if (IS_ROOT(p->dentry)) {
++		if (au_ftest_pin(p->flags, MNT_WRITE)) {
++			p->h_mnt = au_br_mnt(p->br);
++			err = vfsub_mnt_want_write(p->h_mnt);
++			if (unlikely(err)) {
++				au_fclr_pin(p->flags, MNT_WRITE);
++				goto out_err;
++			}
++		}
++		goto out;
++	}
++
++	p->h_dentry = NULL;
++	if (p->bindex <= au_dbend(p->dentry))
++		p->h_dentry = au_h_dptr(p->dentry, p->bindex);
++
++	p->parent = dget_parent(p->dentry);
++	if (!au_ftest_pin(p->flags, DI_LOCKED))
++		di_read_lock(p->parent, AuLock_IR, p->lsc_di);
++
++	h_dir = NULL;
++	p->h_parent = au_h_dptr(p->parent, p->bindex);
++	p->hdir = au_hi(p->parent->d_inode, p->bindex);
++	if (p->hdir)
++		h_dir = p->hdir->hi_inode;
++
++	/*
++	 * udba case, or
++	 * if DI_LOCKED is not set, then p->parent may be different
++	 * and h_parent can be NULL.
++	 */
++	if (unlikely(!p->hdir || !h_dir || !p->h_parent)) {
++		err = -EBUSY;
++		if (!au_ftest_pin(p->flags, DI_LOCKED))
++			di_read_unlock(p->parent, AuLock_IR);
++		dput(p->parent);
++		p->parent = NULL;
++		goto out_err;
++	}
++
++	if (au_ftest_pin(p->flags, MNT_WRITE)) {
++		p->h_mnt = au_br_mnt(p->br);
++		err = vfsub_mnt_want_write(p->h_mnt);
++		if (unlikely(err)) {
++			au_fclr_pin(p->flags, MNT_WRITE);
++			if (!au_ftest_pin(p->flags, DI_LOCKED))
++				di_read_unlock(p->parent, AuLock_IR);
++			dput(p->parent);
++			p->parent = NULL;
++			goto out_err;
++		}
++	}
++
++	au_igrab(h_dir);
++	err = au_pin_hdir_lock(p);
++	if (!err)
++		goto out; /* success */
++
++	au_unpin(p);
++
++out_err:
++	pr_err("err %d\n", err);
++	err = au_busy_or_stale();
++out:
++	return err;
++}
++
++void au_pin_init(struct au_pin *p, struct dentry *dentry,
++		 aufs_bindex_t bindex, int lsc_di, int lsc_hi,
++		 unsigned int udba, unsigned char flags)
++{
++	p->dentry = dentry;
++	p->udba = udba;
++	p->lsc_di = lsc_di;
++	p->lsc_hi = lsc_hi;
++	p->flags = flags;
++	p->bindex = bindex;
++
++	p->parent = NULL;
++	p->hdir = NULL;
++	p->h_mnt = NULL;
++
++	p->h_dentry = NULL;
++	p->h_parent = NULL;
++	p->br = NULL;
++	p->task = current;
++}
++
++int au_pin(struct au_pin *pin, struct dentry *dentry, aufs_bindex_t bindex,
++	   unsigned int udba, unsigned char flags)
++{
++	au_pin_init(pin, dentry, bindex, AuLsc_DI_PARENT, AuLsc_I_PARENT2,
++		    udba, flags);
++	return au_do_pin(pin);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * ->setattr() and ->getattr() are called in various cases.
++ * chmod, stat: dentry is revalidated.
++ * fchmod, fstat: file and dentry are not revalidated, additionally they may be
++ *		  unhashed.
++ * for ->setattr(), ia->ia_file is passed from ftruncate only.
++ */
++/* todo: consolidate with do_refresh() and simple_reval_dpath() */
++int au_reval_for_attr(struct dentry *dentry, unsigned int sigen)
++{
++	int err;
++	struct inode *inode;
++	struct dentry *parent;
++
++	err = 0;
++	inode = dentry->d_inode;
++	if (au_digen_test(dentry, sigen)) {
++		parent = dget_parent(dentry);
++		di_read_lock_parent(parent, AuLock_IR);
++		err = au_refresh_dentry(dentry, parent);
++		di_read_unlock(parent, AuLock_IR);
++		dput(parent);
++	}
++
++	AuTraceErr(err);
++	return err;
++}
++
++int au_pin_and_icpup(struct dentry *dentry, struct iattr *ia,
++		     struct au_icpup_args *a)
++{
++	int err;
++	loff_t sz;
++	aufs_bindex_t bstart, ibstart;
++	struct dentry *hi_wh, *parent;
++	struct inode *inode;
++	struct au_wr_dir_args wr_dir_args = {
++		.force_btgt	= -1,
++		.flags		= 0
++	};
++
++	if (d_is_dir(dentry))
++		au_fset_wrdir(wr_dir_args.flags, ISDIR);
++	/* plink or hi_wh() case */
++	bstart = au_dbstart(dentry);
++	inode = dentry->d_inode;
++	ibstart = au_ibstart(inode);
++	if (bstart != ibstart && !au_test_ro(inode->i_sb, ibstart, inode))
++		wr_dir_args.force_btgt = ibstart;
++	err = au_wr_dir(dentry, /*src_dentry*/NULL, &wr_dir_args);
++	if (unlikely(err < 0))
++		goto out;
++	a->btgt = err;
++	if (err != bstart)
++		au_fset_icpup(a->flags, DID_CPUP);
++
++	err = 0;
++	a->pin_flags = AuPin_MNT_WRITE;
++	parent = NULL;
++	if (!IS_ROOT(dentry)) {
++		au_fset_pin(a->pin_flags, DI_LOCKED);
++		parent = dget_parent(dentry);
++		di_write_lock_parent(parent);
++	}
++
++	err = au_pin(&a->pin, dentry, a->btgt, a->udba, a->pin_flags);
++	if (unlikely(err))
++		goto out_parent;
++
++	a->h_path.dentry = au_h_dptr(dentry, bstart);
++	a->h_inode = a->h_path.dentry->d_inode;
++	sz = -1;
++	if (ia && (ia->ia_valid & ATTR_SIZE)) {
++		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
++		if (ia->ia_size < i_size_read(a->h_inode))
++			sz = ia->ia_size;
++		mutex_unlock(&a->h_inode->i_mutex);
++	}
++
++	hi_wh = NULL;
++	if (au_ftest_icpup(a->flags, DID_CPUP) && d_unlinked(dentry)) {
++		hi_wh = au_hi_wh(inode, a->btgt);
++		if (!hi_wh) {
++			struct au_cp_generic cpg = {
++				.dentry	= dentry,
++				.bdst	= a->btgt,
++				.bsrc	= -1,
++				.len	= sz,
++				.pin	= &a->pin
++			};
++			err = au_sio_cpup_wh(&cpg, /*file*/NULL);
++			if (unlikely(err))
++				goto out_unlock;
++			hi_wh = au_hi_wh(inode, a->btgt);
++			/* todo: revalidate hi_wh? */
++		}
++	}
++
++	if (parent) {
++		au_pin_set_parent_lflag(&a->pin, /*lflag*/0);
++		di_downgrade_lock(parent, AuLock_IR);
++		dput(parent);
++		parent = NULL;
++	}
++	if (!au_ftest_icpup(a->flags, DID_CPUP))
++		goto out; /* success */
++
++	if (!d_unhashed(dentry)) {
++		struct au_cp_generic cpg = {
++			.dentry	= dentry,
++			.bdst	= a->btgt,
++			.bsrc	= bstart,
++			.len	= sz,
++			.pin	= &a->pin,
++			.flags	= AuCpup_DTIME | AuCpup_HOPEN
++		};
++		err = au_sio_cpup_simple(&cpg);
++		if (!err)
++			a->h_path.dentry = au_h_dptr(dentry, a->btgt);
++	} else if (!hi_wh)
++		a->h_path.dentry = au_h_dptr(dentry, a->btgt);
++	else
++		a->h_path.dentry = hi_wh; /* do not dget here */
++
++out_unlock:
++	a->h_inode = a->h_path.dentry->d_inode;
++	if (!err)
++		goto out; /* success */
++	au_unpin(&a->pin);
++out_parent:
++	if (parent) {
++		di_write_unlock(parent);
++		dput(parent);
++	}
++out:
++	if (!err)
++		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
++	return err;
++}
++
++static int aufs_setattr(struct dentry *dentry, struct iattr *ia)
++{
++	int err;
++	struct inode *inode, *delegated;
++	struct super_block *sb;
++	struct file *file;
++	struct au_icpup_args *a;
++
++	inode = dentry->d_inode;
++	IMustLock(inode);
++
++	err = -ENOMEM;
++	a = kzalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
++		ia->ia_valid &= ~ATTR_MODE;
++
++	file = NULL;
++	sb = dentry->d_sb;
++	err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++	if (unlikely(err))
++		goto out_kfree;
++
++	if (ia->ia_valid & ATTR_FILE) {
++		/* currently ftruncate(2) only */
++		AuDebugOn(!d_is_reg(dentry));
++		file = ia->ia_file;
++		err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1);
++		if (unlikely(err))
++			goto out_si;
++		ia->ia_file = au_hf_top(file);
++		a->udba = AuOpt_UDBA_NONE;
++	} else {
++		/* fchmod() doesn't pass ia_file */
++		a->udba = au_opt_udba(sb);
++		di_write_lock_child(dentry);
++		/* no d_unlinked(), to set UDBA_NONE for root */
++		if (d_unhashed(dentry))
++			a->udba = AuOpt_UDBA_NONE;
++		if (a->udba != AuOpt_UDBA_NONE) {
++			AuDebugOn(IS_ROOT(dentry));
++			err = au_reval_for_attr(dentry, au_sigen(sb));
++			if (unlikely(err))
++				goto out_dentry;
++		}
++	}
++
++	err = au_pin_and_icpup(dentry, ia, a);
++	if (unlikely(err < 0))
++		goto out_dentry;
++	if (au_ftest_icpup(a->flags, DID_CPUP)) {
++		ia->ia_file = NULL;
++		ia->ia_valid &= ~ATTR_FILE;
++	}
++
++	a->h_path.mnt = au_sbr_mnt(sb, a->btgt);
++	if ((ia->ia_valid & (ATTR_MODE | ATTR_CTIME))
++	    == (ATTR_MODE | ATTR_CTIME)) {
++		err = security_path_chmod(&a->h_path, ia->ia_mode);
++		if (unlikely(err))
++			goto out_unlock;
++	} else if ((ia->ia_valid & (ATTR_UID | ATTR_GID))
++		   && (ia->ia_valid & ATTR_CTIME)) {
++		err = security_path_chown(&a->h_path, ia->ia_uid, ia->ia_gid);
++		if (unlikely(err))
++			goto out_unlock;
++	}
++
++	if (ia->ia_valid & ATTR_SIZE) {
++		struct file *f;
++
++		if (ia->ia_size < i_size_read(inode))
++			/* unmap only */
++			truncate_setsize(inode, ia->ia_size);
++
++		f = NULL;
++		if (ia->ia_valid & ATTR_FILE)
++			f = ia->ia_file;
++		mutex_unlock(&a->h_inode->i_mutex);
++		err = vfsub_trunc(&a->h_path, ia->ia_size, ia->ia_valid, f);
++		mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
++	} else {
++		delegated = NULL;
++		while (1) {
++			err = vfsub_notify_change(&a->h_path, ia, &delegated);
++			if (delegated) {
++				err = break_deleg_wait(&delegated);
++				if (!err)
++					continue;
++			}
++			break;
++		}
++	}
++	if (!err)
++		au_cpup_attr_changeable(inode);
++
++out_unlock:
++	mutex_unlock(&a->h_inode->i_mutex);
++	au_unpin(&a->pin);
++	if (unlikely(err))
++		au_update_dbstart(dentry);
++out_dentry:
++	di_write_unlock(dentry);
++	if (file) {
++		fi_write_unlock(file);
++		ia->ia_file = file;
++		ia->ia_valid |= ATTR_FILE;
++	}
++out_si:
++	si_read_unlock(sb);
++out_kfree:
++	kfree(a);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++#if IS_ENABLED(CONFIG_AUFS_XATTR) || IS_ENABLED(CONFIG_FS_POSIX_ACL)
++static int au_h_path_to_set_attr(struct dentry *dentry,
++				 struct au_icpup_args *a, struct path *h_path)
++{
++	int err;
++	struct super_block *sb;
++
++	sb = dentry->d_sb;
++	a->udba = au_opt_udba(sb);
++	/* no d_unlinked(), to set UDBA_NONE for root */
++	if (d_unhashed(dentry))
++		a->udba = AuOpt_UDBA_NONE;
++	if (a->udba != AuOpt_UDBA_NONE) {
++		AuDebugOn(IS_ROOT(dentry));
++		err = au_reval_for_attr(dentry, au_sigen(sb));
++		if (unlikely(err))
++			goto out;
++	}
++	err = au_pin_and_icpup(dentry, /*ia*/NULL, a);
++	if (unlikely(err < 0))
++		goto out;
++
++	h_path->dentry = a->h_path.dentry;
++	h_path->mnt = au_sbr_mnt(sb, a->btgt);
++
++out:
++	return err;
++}
++
++ssize_t au_srxattr(struct dentry *dentry, struct au_srxattr *arg)
++{
++	int err;
++	struct path h_path;
++	struct super_block *sb;
++	struct au_icpup_args *a;
++	struct inode *inode, *h_inode;
++
++	inode = dentry->d_inode;
++	IMustLock(inode);
++
++	err = -ENOMEM;
++	a = kzalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	sb = dentry->d_sb;
++	err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++	if (unlikely(err))
++		goto out_kfree;
++
++	h_path.dentry = NULL;	/* silence gcc */
++	di_write_lock_child(dentry);
++	err = au_h_path_to_set_attr(dentry, a, &h_path);
++	if (unlikely(err))
++		goto out_di;
++
++	mutex_unlock(&a->h_inode->i_mutex);
++	switch (arg->type) {
++	case AU_XATTR_SET:
++		err = vfsub_setxattr(h_path.dentry,
++				     arg->u.set.name, arg->u.set.value,
++				     arg->u.set.size, arg->u.set.flags);
++		break;
++	case AU_XATTR_REMOVE:
++		err = vfsub_removexattr(h_path.dentry, arg->u.remove.name);
++		break;
++	case AU_ACL_SET:
++		err = -EOPNOTSUPP;
++		h_inode = h_path.dentry->d_inode;
++		if (h_inode->i_op->set_acl)
++			err = h_inode->i_op->set_acl(h_inode,
++						     arg->u.acl_set.acl,
++						     arg->u.acl_set.type);
++		break;
++	}
++	if (!err)
++		au_cpup_attr_timesizes(inode);
++
++	au_unpin(&a->pin);
++	if (unlikely(err))
++		au_update_dbstart(dentry);
++
++out_di:
++	di_write_unlock(dentry);
++	si_read_unlock(sb);
++out_kfree:
++	kfree(a);
++out:
++	AuTraceErr(err);
++	return err;
++}
++#endif
++
++static void au_refresh_iattr(struct inode *inode, struct kstat *st,
++			     unsigned int nlink)
++{
++	unsigned int n;
++
++	inode->i_mode = st->mode;
++	/* don't i_[ug]id_write() here */
++	inode->i_uid = st->uid;
++	inode->i_gid = st->gid;
++	inode->i_atime = st->atime;
++	inode->i_mtime = st->mtime;
++	inode->i_ctime = st->ctime;
++
++	au_cpup_attr_nlink(inode, /*force*/0);
++	if (S_ISDIR(inode->i_mode)) {
++		n = inode->i_nlink;
++		n -= nlink;
++		n += st->nlink;
++		smp_mb(); /* for i_nlink */
++		/* 0 can happen */
++		set_nlink(inode, n);
++	}
++
++	spin_lock(&inode->i_lock);
++	inode->i_blocks = st->blocks;
++	i_size_write(inode, st->size);
++	spin_unlock(&inode->i_lock);
++}
++
++/*
++ * common routine for aufs_getattr() and aufs_getxattr().
++ * returns zero or negative (an error).
++ * @dentry will be read-locked in success.
++ */
++int au_h_path_getattr(struct dentry *dentry, int force, struct path *h_path)
++{
++	int err;
++	unsigned int mnt_flags, sigen;
++	unsigned char udba_none;
++	aufs_bindex_t bindex;
++	struct super_block *sb, *h_sb;
++	struct inode *inode;
++
++	h_path->mnt = NULL;
++	h_path->dentry = NULL;
++
++	err = 0;
++	sb = dentry->d_sb;
++	mnt_flags = au_mntflags(sb);
++	udba_none = !!au_opt_test(mnt_flags, UDBA_NONE);
++
++	/* support fstat(2) */
++	if (!d_unlinked(dentry) && !udba_none) {
++		sigen = au_sigen(sb);
++		err = au_digen_test(dentry, sigen);
++		if (!err) {
++			di_read_lock_child(dentry, AuLock_IR);
++			err = au_dbrange_test(dentry);
++			if (unlikely(err)) {
++				di_read_unlock(dentry, AuLock_IR);
++				goto out;
++			}
++		} else {
++			AuDebugOn(IS_ROOT(dentry));
++			di_write_lock_child(dentry);
++			err = au_dbrange_test(dentry);
++			if (!err)
++				err = au_reval_for_attr(dentry, sigen);
++			if (!err)
++				di_downgrade_lock(dentry, AuLock_IR);
++			else {
++				di_write_unlock(dentry);
++				goto out;
++			}
++		}
++	} else
++		di_read_lock_child(dentry, AuLock_IR);
++
++	inode = dentry->d_inode;
++	bindex = au_ibstart(inode);
++	h_path->mnt = au_sbr_mnt(sb, bindex);
++	h_sb = h_path->mnt->mnt_sb;
++	if (!force
++	    && !au_test_fs_bad_iattr(h_sb)
++	    && udba_none)
++		goto out; /* success */
++
++	if (au_dbstart(dentry) == bindex)
++		h_path->dentry = au_h_dptr(dentry, bindex);
++	else if (au_opt_test(mnt_flags, PLINK) && au_plink_test(inode)) {
++		h_path->dentry = au_plink_lkup(inode, bindex);
++		if (IS_ERR(h_path->dentry))
++			/* pretending success */
++			h_path->dentry = NULL;
++		else
++			dput(h_path->dentry);
++	}
++
++out:
++	return err;
++}
++
++static int aufs_getattr(struct vfsmount *mnt __maybe_unused,
++			struct dentry *dentry, struct kstat *st)
++{
++	int err;
++	unsigned char positive;
++	struct path h_path;
++	struct inode *inode;
++	struct super_block *sb;
++
++	inode = dentry->d_inode;
++	sb = dentry->d_sb;
++	err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++	if (unlikely(err))
++		goto out;
++	err = au_h_path_getattr(dentry, /*force*/0, &h_path);
++	if (unlikely(err))
++		goto out_si;
++	if (unlikely(!h_path.dentry))
++		/* illegally overlapped or something */
++		goto out_fill; /* pretending success */
++
++	positive = !!h_path.dentry->d_inode;
++	if (positive)
++		err = vfs_getattr(&h_path, st);
++	if (!err) {
++		if (positive)
++			au_refresh_iattr(inode, st,
++					 h_path.dentry->d_inode->i_nlink);
++		goto out_fill; /* success */
++	}
++	AuTraceErr(err);
++	goto out_di;
++
++out_fill:
++	generic_fillattr(inode, st);
++out_di:
++	di_read_unlock(dentry, AuLock_IR);
++out_si:
++	si_read_unlock(sb);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int h_readlink(struct dentry *dentry, int bindex, char __user *buf,
++		      int bufsiz)
++{
++	int err;
++	struct super_block *sb;
++	struct dentry *h_dentry;
++
++	err = -EINVAL;
++	h_dentry = au_h_dptr(dentry, bindex);
++	if (unlikely(!h_dentry->d_inode->i_op->readlink))
++		goto out;
++
++	err = security_inode_readlink(h_dentry);
++	if (unlikely(err))
++		goto out;
++
++	sb = dentry->d_sb;
++	if (!au_test_ro(sb, bindex, dentry->d_inode)) {
++		vfsub_touch_atime(au_sbr_mnt(sb, bindex), h_dentry);
++		fsstack_copy_attr_atime(dentry->d_inode, h_dentry->d_inode);
++	}
++	err = h_dentry->d_inode->i_op->readlink(h_dentry, buf, bufsiz);
++
++out:
++	return err;
++}
++
++static int aufs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
++{
++	int err;
++
++	err = aufs_read_lock(dentry, AuLock_IR | AuLock_GEN);
++	if (unlikely(err))
++		goto out;
++	err = au_d_hashed_positive(dentry);
++	if (!err)
++		err = h_readlink(dentry, au_dbstart(dentry), buf, bufsiz);
++	aufs_read_unlock(dentry, AuLock_IR);
++
++out:
++	return err;
++}
++
++static void *aufs_follow_link(struct dentry *dentry, struct nameidata *nd)
++{
++	int err;
++	mm_segment_t old_fs;
++	union {
++		char *k;
++		char __user *u;
++	} buf;
++
++	err = -ENOMEM;
++	buf.k = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!buf.k))
++		goto out;
++
++	err = aufs_read_lock(dentry, AuLock_IR | AuLock_GEN);
++	if (unlikely(err))
++		goto out_name;
++
++	err = au_d_hashed_positive(dentry);
++	if (!err) {
++		old_fs = get_fs();
++		set_fs(KERNEL_DS);
++		err = h_readlink(dentry, au_dbstart(dentry), buf.u, PATH_MAX);
++		set_fs(old_fs);
++	}
++	aufs_read_unlock(dentry, AuLock_IR);
++
++	if (err >= 0) {
++		buf.k[err] = 0;
++		/* will be freed by put_link */
++		nd_set_link(nd, buf.k);
++		return NULL; /* success */
++	}
++
++out_name:
++	free_page((unsigned long)buf.k);
++out:
++	AuTraceErr(err);
++	return ERR_PTR(err);
++}
++
++static void aufs_put_link(struct dentry *dentry __maybe_unused,
++			  struct nameidata *nd, void *cookie __maybe_unused)
++{
++	char *p;
++
++	p = nd_get_link(nd);
++	if (!IS_ERR_OR_NULL(p))
++		free_page((unsigned long)p);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int aufs_update_time(struct inode *inode, struct timespec *ts, int flags)
++{
++	int err;
++	struct super_block *sb;
++	struct inode *h_inode;
++
++	sb = inode->i_sb;
++	/* mmap_sem might be acquired already, cf. aufs_mmap() */
++	lockdep_off();
++	si_read_lock(sb, AuLock_FLUSH);
++	ii_write_lock_child(inode);
++	lockdep_on();
++	h_inode = au_h_iptr(inode, au_ibstart(inode));
++	err = vfsub_update_time(h_inode, ts, flags);
++	lockdep_off();
++	if (!err)
++		au_cpup_attr_timesizes(inode);
++	ii_write_unlock(inode);
++	si_read_unlock(sb);
++	lockdep_on();
++
++	if (!err && (flags & S_VERSION))
++		inode_inc_iversion(inode);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct inode_operations aufs_symlink_iop = {
++	.permission	= aufs_permission,
++#ifdef CONFIG_FS_POSIX_ACL
++	.get_acl	= aufs_get_acl,
++	.set_acl	= aufs_set_acl, /* unsupport for symlink? */
++#endif
++
++	.setattr	= aufs_setattr,
++	.getattr	= aufs_getattr,
++
++#ifdef CONFIG_AUFS_XATTR
++	.setxattr	= aufs_setxattr,
++	.getxattr	= aufs_getxattr,
++	.listxattr	= aufs_listxattr,
++	.removexattr	= aufs_removexattr,
++#endif
++
++	.readlink	= aufs_readlink,
++	.follow_link	= aufs_follow_link,
++	.put_link	= aufs_put_link,
++
++	/* .update_time	= aufs_update_time */
++};
++
++struct inode_operations aufs_dir_iop = {
++	.create		= aufs_create,
++	.lookup		= aufs_lookup,
++	.link		= aufs_link,
++	.unlink		= aufs_unlink,
++	.symlink	= aufs_symlink,
++	.mkdir		= aufs_mkdir,
++	.rmdir		= aufs_rmdir,
++	.mknod		= aufs_mknod,
++	.rename		= aufs_rename,
++
++	.permission	= aufs_permission,
++#ifdef CONFIG_FS_POSIX_ACL
++	.get_acl	= aufs_get_acl,
++	.set_acl	= aufs_set_acl,
++#endif
++
++	.setattr	= aufs_setattr,
++	.getattr	= aufs_getattr,
++
++#ifdef CONFIG_AUFS_XATTR
++	.setxattr	= aufs_setxattr,
++	.getxattr	= aufs_getxattr,
++	.listxattr	= aufs_listxattr,
++	.removexattr	= aufs_removexattr,
++#endif
++
++	.update_time	= aufs_update_time,
++	.atomic_open	= aufs_atomic_open,
++	.tmpfile	= aufs_tmpfile
++};
++
++struct inode_operations aufs_iop = {
++	.permission	= aufs_permission,
++#ifdef CONFIG_FS_POSIX_ACL
++	.get_acl	= aufs_get_acl,
++	.set_acl	= aufs_set_acl,
++#endif
++
++	.setattr	= aufs_setattr,
++	.getattr	= aufs_getattr,
++
++#ifdef CONFIG_AUFS_XATTR
++	.setxattr	= aufs_setxattr,
++	.getxattr	= aufs_getxattr,
++	.listxattr	= aufs_listxattr,
++	.removexattr	= aufs_removexattr,
++#endif
++
++	.update_time	= aufs_update_time
++};
+diff -Nur linux-4.0.4.orig/fs/aufs/i_op_del.c linux-4.0.4/fs/aufs/i_op_del.c
+--- linux-4.0.4.orig/fs/aufs/i_op_del.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/i_op_del.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,493 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * inode operations (del entry)
++ */
++
++#include "aufs.h"
++
++/*
++ * decide if a new whiteout for @dentry is necessary or not.
++ * when it is necessary, prepare the parent dir for the upper branch whose
++ * branch index is @bcpup for creation. the actual creation of the whiteout will
++ * be done by caller.
++ * return value:
++ * 0: wh is unnecessary
++ * plus: wh is necessary
++ * minus: error
++ */
++int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
++{
++	int need_wh, err;
++	aufs_bindex_t bstart;
++	struct super_block *sb;
++
++	sb = dentry->d_sb;
++	bstart = au_dbstart(dentry);
++	if (*bcpup < 0) {
++		*bcpup = bstart;
++		if (au_test_ro(sb, bstart, dentry->d_inode)) {
++			err = AuWbrCopyup(au_sbi(sb), dentry);
++			*bcpup = err;
++			if (unlikely(err < 0))
++				goto out;
++		}
++	} else
++		AuDebugOn(bstart < *bcpup
++			  || au_test_ro(sb, *bcpup, dentry->d_inode));
++	AuDbg("bcpup %d, bstart %d\n", *bcpup, bstart);
++
++	if (*bcpup != bstart) {
++		err = au_cpup_dirs(dentry, *bcpup);
++		if (unlikely(err))
++			goto out;
++		need_wh = 1;
++	} else {
++		struct au_dinfo *dinfo, *tmp;
++
++		need_wh = -ENOMEM;
++		dinfo = au_di(dentry);
++		tmp = au_di_alloc(sb, AuLsc_DI_TMP);
++		if (tmp) {
++			au_di_cp(tmp, dinfo);
++			au_di_swap(tmp, dinfo);
++			/* returns the number of positive dentries */
++			need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0);
++			au_di_swap(tmp, dinfo);
++			au_rw_write_unlock(&tmp->di_rwsem);
++			au_di_free(tmp);
++		}
++	}
++	AuDbg("need_wh %d\n", need_wh);
++	err = need_wh;
++
++out:
++	return err;
++}
++
++/*
++ * simple tests for the del-entry operations.
++ * following the checks in vfs, plus the parent-child relationship.
++ */
++int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
++	       struct dentry *h_parent, int isdir)
++{
++	int err;
++	umode_t h_mode;
++	struct dentry *h_dentry, *h_latest;
++	struct inode *h_inode;
++
++	h_dentry = au_h_dptr(dentry, bindex);
++	h_inode = h_dentry->d_inode;
++	if (dentry->d_inode) {
++		err = -ENOENT;
++		if (unlikely(!h_inode || !h_inode->i_nlink))
++			goto out;
++
++		h_mode = h_inode->i_mode;
++		if (!isdir) {
++			err = -EISDIR;
++			if (unlikely(S_ISDIR(h_mode)))
++				goto out;
++		} else if (unlikely(!S_ISDIR(h_mode))) {
++			err = -ENOTDIR;
++			goto out;
++		}
++	} else {
++		/* rename(2) case */
++		err = -EIO;
++		if (unlikely(h_inode))
++			goto out;
++	}
++
++	err = -ENOENT;
++	/* expected parent dir is locked */
++	if (unlikely(h_parent != h_dentry->d_parent))
++		goto out;
++	err = 0;
++
++	/*
++	 * rmdir a dir may break the consistency on some filesystem.
++	 * let's try heavy test.
++	 */
++	err = -EACCES;
++	if (unlikely(!au_opt_test(au_mntflags(dentry->d_sb), DIRPERM1)
++		     && au_test_h_perm(h_parent->d_inode,
++				       MAY_EXEC | MAY_WRITE)))
++		goto out;
++
++	h_latest = au_sio_lkup_one(&dentry->d_name, h_parent);
++	err = -EIO;
++	if (IS_ERR(h_latest))
++		goto out;
++	if (h_latest == h_dentry)
++		err = 0;
++	dput(h_latest);
++
++out:
++	return err;
++}
++
++/*
++ * decide the branch where we operate for @dentry. the branch index will be set
++ * @rbcpup. after diciding it, 'pin' it and store the timestamps of the parent
++ * dir for reverting.
++ * when a new whiteout is necessary, create it.
++ */
++static struct dentry*
++lock_hdir_create_wh(struct dentry *dentry, int isdir, aufs_bindex_t *rbcpup,
++		    struct au_dtime *dt, struct au_pin *pin)
++{
++	struct dentry *wh_dentry;
++	struct super_block *sb;
++	struct path h_path;
++	int err, need_wh;
++	unsigned int udba;
++	aufs_bindex_t bcpup;
++
++	need_wh = au_wr_dir_need_wh(dentry, isdir, rbcpup);
++	wh_dentry = ERR_PTR(need_wh);
++	if (unlikely(need_wh < 0))
++		goto out;
++
++	sb = dentry->d_sb;
++	udba = au_opt_udba(sb);
++	bcpup = *rbcpup;
++	err = au_pin(pin, dentry, bcpup, udba,
++		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++	wh_dentry = ERR_PTR(err);
++	if (unlikely(err))
++		goto out;
++
++	h_path.dentry = au_pinned_h_parent(pin);
++	if (udba != AuOpt_UDBA_NONE
++	    && au_dbstart(dentry) == bcpup) {
++		err = au_may_del(dentry, bcpup, h_path.dentry, isdir);
++		wh_dentry = ERR_PTR(err);
++		if (unlikely(err))
++			goto out_unpin;
++	}
++
++	h_path.mnt = au_sbr_mnt(sb, bcpup);
++	au_dtime_store(dt, au_pinned_parent(pin), &h_path);
++	wh_dentry = NULL;
++	if (!need_wh)
++		goto out; /* success, no need to create whiteout */
++
++	wh_dentry = au_wh_create(dentry, bcpup, h_path.dentry);
++	if (IS_ERR(wh_dentry))
++		goto out_unpin;
++
++	/* returns with the parent is locked and wh_dentry is dget-ed */
++	goto out; /* success */
++
++out_unpin:
++	au_unpin(pin);
++out:
++	return wh_dentry;
++}
++
++/*
++ * when removing a dir, rename it to a unique temporary whiteout-ed name first
++ * in order to be revertible and save time for removing many child whiteouts
++ * under the dir.
++ * returns 1 when there are too many child whiteout and caller should remove
++ * them asynchronously. returns 0 when the number of children is enough small to
++ * remove now or the branch fs is a remote fs.
++ * otherwise return an error.
++ */
++static int renwh_and_rmdir(struct dentry *dentry, aufs_bindex_t bindex,
++			   struct au_nhash *whlist, struct inode *dir)
++{
++	int rmdir_later, err, dirwh;
++	struct dentry *h_dentry;
++	struct super_block *sb;
++
++	sb = dentry->d_sb;
++	SiMustAnyLock(sb);
++	h_dentry = au_h_dptr(dentry, bindex);
++	err = au_whtmp_ren(h_dentry, au_sbr(sb, bindex));
++	if (unlikely(err))
++		goto out;
++
++	/* stop monitoring */
++	au_hn_free(au_hi(dentry->d_inode, bindex));
++
++	if (!au_test_fs_remote(h_dentry->d_sb)) {
++		dirwh = au_sbi(sb)->si_dirwh;
++		rmdir_later = (dirwh <= 1);
++		if (!rmdir_later)
++			rmdir_later = au_nhash_test_longer_wh(whlist, bindex,
++							      dirwh);
++		if (rmdir_later)
++			return rmdir_later;
++	}
++
++	err = au_whtmp_rmdir(dir, bindex, h_dentry, whlist);
++	if (unlikely(err)) {
++		AuIOErr("rmdir %pd, b%d failed, %d. ignored\n",
++			h_dentry, bindex, err);
++		err = 0;
++	}
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/*
++ * final procedure for deleting a entry.
++ * maintain dentry and iattr.
++ */
++static void epilog(struct inode *dir, struct dentry *dentry,
++		   aufs_bindex_t bindex)
++{
++	struct inode *inode;
++
++	inode = dentry->d_inode;
++	d_drop(dentry);
++	inode->i_ctime = dir->i_ctime;
++
++	au_dir_ts(dir, bindex);
++	dir->i_version++;
++}
++
++/*
++ * when an error happened, remove the created whiteout and revert everything.
++ */
++static int do_revert(int err, struct inode *dir, aufs_bindex_t bindex,
++		     aufs_bindex_t bwh, struct dentry *wh_dentry,
++		     struct dentry *dentry, struct au_dtime *dt)
++{
++	int rerr;
++	struct path h_path = {
++		.dentry	= wh_dentry,
++		.mnt	= au_sbr_mnt(dir->i_sb, bindex)
++	};
++
++	rerr = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path, dentry);
++	if (!rerr) {
++		au_set_dbwh(dentry, bwh);
++		au_dtime_revert(dt);
++		return 0;
++	}
++
++	AuIOErr("%pd reverting whiteout failed(%d, %d)\n", dentry, err, rerr);
++	return -EIO;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int aufs_unlink(struct inode *dir, struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bwh, bindex, bstart;
++	struct inode *inode, *h_dir, *delegated;
++	struct dentry *parent, *wh_dentry;
++	/* to reuduce stack size */
++	struct {
++		struct au_dtime dt;
++		struct au_pin pin;
++		struct path h_path;
++	} *a;
++
++	IMustLock(dir);
++
++	err = -ENOMEM;
++	a = kmalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
++	if (unlikely(err))
++		goto out_free;
++	err = au_d_hashed_positive(dentry);
++	if (unlikely(err))
++		goto out_unlock;
++	inode = dentry->d_inode;
++	IMustLock(inode);
++	err = -EISDIR;
++	if (unlikely(d_is_dir(dentry)))
++		goto out_unlock; /* possible? */
++
++	bstart = au_dbstart(dentry);
++	bwh = au_dbwh(dentry);
++	bindex = -1;
++	parent = dentry->d_parent; /* dir inode is locked */
++	di_write_lock_parent(parent);
++	wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/0, &bindex, &a->dt,
++					&a->pin);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out_parent;
++
++	a->h_path.mnt = au_sbr_mnt(dentry->d_sb, bstart);
++	a->h_path.dentry = au_h_dptr(dentry, bstart);
++	dget(a->h_path.dentry);
++	if (bindex == bstart) {
++		h_dir = au_pinned_h_dir(&a->pin);
++		delegated = NULL;
++		err = vfsub_unlink(h_dir, &a->h_path, &delegated, /*force*/0);
++		if (unlikely(err == -EWOULDBLOCK)) {
++			pr_warn("cannot retry for NFSv4 delegation"
++				" for an internal unlink\n");
++			iput(delegated);
++		}
++	} else {
++		/* dir inode is locked */
++		h_dir = wh_dentry->d_parent->d_inode;
++		IMustLock(h_dir);
++		err = 0;
++	}
++
++	if (!err) {
++		vfsub_drop_nlink(inode);
++		epilog(dir, dentry, bindex);
++
++		/* update target timestamps */
++		if (bindex == bstart) {
++			vfsub_update_h_iattr(&a->h_path, /*did*/NULL);
++			/*ignore*/
++			inode->i_ctime = a->h_path.dentry->d_inode->i_ctime;
++		} else
++			/* todo: this timestamp may be reverted later */
++			inode->i_ctime = h_dir->i_ctime;
++		goto out_unpin; /* success */
++	}
++
++	/* revert */
++	if (wh_dentry) {
++		int rerr;
++
++		rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry,
++				 &a->dt);
++		if (rerr)
++			err = rerr;
++	}
++
++out_unpin:
++	au_unpin(&a->pin);
++	dput(wh_dentry);
++	dput(a->h_path.dentry);
++out_parent:
++	di_write_unlock(parent);
++out_unlock:
++	aufs_read_unlock(dentry, AuLock_DW);
++out_free:
++	kfree(a);
++out:
++	return err;
++}
++
++int aufs_rmdir(struct inode *dir, struct dentry *dentry)
++{
++	int err, rmdir_later;
++	aufs_bindex_t bwh, bindex, bstart;
++	struct inode *inode;
++	struct dentry *parent, *wh_dentry, *h_dentry;
++	struct au_whtmp_rmdir *args;
++	/* to reuduce stack size */
++	struct {
++		struct au_dtime dt;
++		struct au_pin pin;
++	} *a;
++
++	IMustLock(dir);
++
++	err = -ENOMEM;
++	a = kmalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH | AuLock_GEN);
++	if (unlikely(err))
++		goto out_free;
++	err = au_alive_dir(dentry);
++	if (unlikely(err))
++		goto out_unlock;
++	inode = dentry->d_inode;
++	IMustLock(inode);
++	err = -ENOTDIR;
++	if (unlikely(!d_is_dir(dentry)))
++		goto out_unlock; /* possible? */
++
++	err = -ENOMEM;
++	args = au_whtmp_rmdir_alloc(dir->i_sb, GFP_NOFS);
++	if (unlikely(!args))
++		goto out_unlock;
++
++	parent = dentry->d_parent; /* dir inode is locked */
++	di_write_lock_parent(parent);
++	err = au_test_empty(dentry, &args->whlist);
++	if (unlikely(err))
++		goto out_parent;
++
++	bstart = au_dbstart(dentry);
++	bwh = au_dbwh(dentry);
++	bindex = -1;
++	wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/1, &bindex, &a->dt,
++					&a->pin);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry))
++		goto out_parent;
++
++	h_dentry = au_h_dptr(dentry, bstart);
++	dget(h_dentry);
++	rmdir_later = 0;
++	if (bindex == bstart) {
++		err = renwh_and_rmdir(dentry, bstart, &args->whlist, dir);
++		if (err > 0) {
++			rmdir_later = err;
++			err = 0;
++		}
++	} else {
++		/* stop monitoring */
++		au_hn_free(au_hi(inode, bstart));
++
++		/* dir inode is locked */
++		IMustLock(wh_dentry->d_parent->d_inode);
++		err = 0;
++	}
++
++	if (!err) {
++		vfsub_dead_dir(inode);
++		au_set_dbdiropq(dentry, -1);
++		epilog(dir, dentry, bindex);
++
++		if (rmdir_later) {
++			au_whtmp_kick_rmdir(dir, bstart, h_dentry, args);
++			args = NULL;
++		}
++
++		goto out_unpin; /* success */
++	}
++
++	/* revert */
++	AuLabel(revert);
++	if (wh_dentry) {
++		int rerr;
++
++		rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry,
++				 &a->dt);
++		if (rerr)
++			err = rerr;
++	}
++
++out_unpin:
++	au_unpin(&a->pin);
++	dput(wh_dentry);
++	dput(h_dentry);
++out_parent:
++	di_write_unlock(parent);
++	if (args)
++		au_whtmp_rmdir_free(args);
++out_unlock:
++	aufs_read_unlock(dentry, AuLock_DW);
++out_free:
++	kfree(a);
++out:
++	AuTraceErr(err);
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/i_op_ren.c linux-4.0.4/fs/aufs/i_op_ren.c
+--- linux-4.0.4.orig/fs/aufs/i_op_ren.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/i_op_ren.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,1002 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * inode operation (rename entry)
++ * todo: this is crazy monster
++ */
++
++#include "aufs.h"
++
++enum { AuSRC, AuDST, AuSrcDst };
++enum { AuPARENT, AuCHILD, AuParentChild };
++
++#define AuRen_ISDIR	1
++#define AuRen_ISSAMEDIR	(1 << 1)
++#define AuRen_WHSRC	(1 << 2)
++#define AuRen_WHDST	(1 << 3)
++#define AuRen_MNT_WRITE	(1 << 4)
++#define AuRen_DT_DSTDIR	(1 << 5)
++#define AuRen_DIROPQ	(1 << 6)
++#define au_ftest_ren(flags, name)	((flags) & AuRen_##name)
++#define au_fset_ren(flags, name) \
++	do { (flags) |= AuRen_##name; } while (0)
++#define au_fclr_ren(flags, name) \
++	do { (flags) &= ~AuRen_##name; } while (0)
++
++struct au_ren_args {
++	struct {
++		struct dentry *dentry, *h_dentry, *parent, *h_parent,
++			*wh_dentry;
++		struct inode *dir, *inode;
++		struct au_hinode *hdir;
++		struct au_dtime dt[AuParentChild];
++		aufs_bindex_t bstart;
++	} sd[AuSrcDst];
++
++#define src_dentry	sd[AuSRC].dentry
++#define src_dir		sd[AuSRC].dir
++#define src_inode	sd[AuSRC].inode
++#define src_h_dentry	sd[AuSRC].h_dentry
++#define src_parent	sd[AuSRC].parent
++#define src_h_parent	sd[AuSRC].h_parent
++#define src_wh_dentry	sd[AuSRC].wh_dentry
++#define src_hdir	sd[AuSRC].hdir
++#define src_h_dir	sd[AuSRC].hdir->hi_inode
++#define src_dt		sd[AuSRC].dt
++#define src_bstart	sd[AuSRC].bstart
++
++#define dst_dentry	sd[AuDST].dentry
++#define dst_dir		sd[AuDST].dir
++#define dst_inode	sd[AuDST].inode
++#define dst_h_dentry	sd[AuDST].h_dentry
++#define dst_parent	sd[AuDST].parent
++#define dst_h_parent	sd[AuDST].h_parent
++#define dst_wh_dentry	sd[AuDST].wh_dentry
++#define dst_hdir	sd[AuDST].hdir
++#define dst_h_dir	sd[AuDST].hdir->hi_inode
++#define dst_dt		sd[AuDST].dt
++#define dst_bstart	sd[AuDST].bstart
++
++	struct dentry *h_trap;
++	struct au_branch *br;
++	struct au_hinode *src_hinode;
++	struct path h_path;
++	struct au_nhash whlist;
++	aufs_bindex_t btgt, src_bwh, src_bdiropq;
++
++	unsigned int flags;
++
++	struct au_whtmp_rmdir *thargs;
++	struct dentry *h_dst;
++};
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * functions for reverting.
++ * when an error happened in a single rename systemcall, we should revert
++ * everything as if nothing happend.
++ * we don't need to revert the copied-up/down the parent dir since they are
++ * harmless.
++ */
++
++#define RevertFailure(fmt, ...) do { \
++	AuIOErr("revert failure: " fmt " (%d, %d)\n", \
++		##__VA_ARGS__, err, rerr); \
++	err = -EIO; \
++} while (0)
++
++static void au_ren_rev_diropq(int err, struct au_ren_args *a)
++{
++	int rerr;
++
++	au_hn_imtx_lock_nested(a->src_hinode, AuLsc_I_CHILD);
++	rerr = au_diropq_remove(a->src_dentry, a->btgt);
++	au_hn_imtx_unlock(a->src_hinode);
++	au_set_dbdiropq(a->src_dentry, a->src_bdiropq);
++	if (rerr)
++		RevertFailure("remove diropq %pd", a->src_dentry);
++}
++
++static void au_ren_rev_rename(int err, struct au_ren_args *a)
++{
++	int rerr;
++	struct inode *delegated;
++
++	a->h_path.dentry = vfsub_lkup_one(&a->src_dentry->d_name,
++					  a->src_h_parent);
++	rerr = PTR_ERR(a->h_path.dentry);
++	if (IS_ERR(a->h_path.dentry)) {
++		RevertFailure("lkup one %pd", a->src_dentry);
++		return;
++	}
++
++	delegated = NULL;
++	rerr = vfsub_rename(a->dst_h_dir,
++			    au_h_dptr(a->src_dentry, a->btgt),
++			    a->src_h_dir, &a->h_path, &delegated);
++	if (unlikely(rerr == -EWOULDBLOCK)) {
++		pr_warn("cannot retry for NFSv4 delegation"
++			" for an internal rename\n");
++		iput(delegated);
++	}
++	d_drop(a->h_path.dentry);
++	dput(a->h_path.dentry);
++	/* au_set_h_dptr(a->src_dentry, a->btgt, NULL); */
++	if (rerr)
++		RevertFailure("rename %pd", a->src_dentry);
++}
++
++static void au_ren_rev_whtmp(int err, struct au_ren_args *a)
++{
++	int rerr;
++	struct inode *delegated;
++
++	a->h_path.dentry = vfsub_lkup_one(&a->dst_dentry->d_name,
++					  a->dst_h_parent);
++	rerr = PTR_ERR(a->h_path.dentry);
++	if (IS_ERR(a->h_path.dentry)) {
++		RevertFailure("lkup one %pd", a->dst_dentry);
++		return;
++	}
++	if (a->h_path.dentry->d_inode) {
++		d_drop(a->h_path.dentry);
++		dput(a->h_path.dentry);
++		return;
++	}
++
++	delegated = NULL;
++	rerr = vfsub_rename(a->dst_h_dir, a->h_dst, a->dst_h_dir, &a->h_path,
++			    &delegated);
++	if (unlikely(rerr == -EWOULDBLOCK)) {
++		pr_warn("cannot retry for NFSv4 delegation"
++			" for an internal rename\n");
++		iput(delegated);
++	}
++	d_drop(a->h_path.dentry);
++	dput(a->h_path.dentry);
++	if (!rerr)
++		au_set_h_dptr(a->dst_dentry, a->btgt, dget(a->h_dst));
++	else
++		RevertFailure("rename %pd", a->h_dst);
++}
++
++static void au_ren_rev_whsrc(int err, struct au_ren_args *a)
++{
++	int rerr;
++
++	a->h_path.dentry = a->src_wh_dentry;
++	rerr = au_wh_unlink_dentry(a->src_h_dir, &a->h_path, a->src_dentry);
++	au_set_dbwh(a->src_dentry, a->src_bwh);
++	if (rerr)
++		RevertFailure("unlink %pd", a->src_wh_dentry);
++}
++#undef RevertFailure
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * when we have to copyup the renaming entry, do it with the rename-target name
++ * in order to minimize the cost (the later actual rename is unnecessary).
++ * otherwise rename it on the target branch.
++ */
++static int au_ren_or_cpup(struct au_ren_args *a)
++{
++	int err;
++	struct dentry *d;
++	struct inode *delegated;
++
++	d = a->src_dentry;
++	if (au_dbstart(d) == a->btgt) {
++		a->h_path.dentry = a->dst_h_dentry;
++		if (au_ftest_ren(a->flags, DIROPQ)
++		    && au_dbdiropq(d) == a->btgt)
++			au_fclr_ren(a->flags, DIROPQ);
++		AuDebugOn(au_dbstart(d) != a->btgt);
++		delegated = NULL;
++		err = vfsub_rename(a->src_h_dir, au_h_dptr(d, a->btgt),
++				   a->dst_h_dir, &a->h_path, &delegated);
++		if (unlikely(err == -EWOULDBLOCK)) {
++			pr_warn("cannot retry for NFSv4 delegation"
++				" for an internal rename\n");
++			iput(delegated);
++		}
++	} else
++		BUG();
++
++	if (!err && a->h_dst)
++		/* it will be set to dinfo later */
++		dget(a->h_dst);
++
++	return err;
++}
++
++/* cf. aufs_rmdir() */
++static int au_ren_del_whtmp(struct au_ren_args *a)
++{
++	int err;
++	struct inode *dir;
++
++	dir = a->dst_dir;
++	SiMustAnyLock(dir->i_sb);
++	if (!au_nhash_test_longer_wh(&a->whlist, a->btgt,
++				     au_sbi(dir->i_sb)->si_dirwh)
++	    || au_test_fs_remote(a->h_dst->d_sb)) {
++		err = au_whtmp_rmdir(dir, a->btgt, a->h_dst, &a->whlist);
++		if (unlikely(err))
++			pr_warn("failed removing whtmp dir %pd (%d), "
++				"ignored.\n", a->h_dst, err);
++	} else {
++		au_nhash_wh_free(&a->thargs->whlist);
++		a->thargs->whlist = a->whlist;
++		a->whlist.nh_num = 0;
++		au_whtmp_kick_rmdir(dir, a->btgt, a->h_dst, a->thargs);
++		dput(a->h_dst);
++		a->thargs = NULL;
++	}
++
++	return 0;
++}
++
++/* make it 'opaque' dir. */
++static int au_ren_diropq(struct au_ren_args *a)
++{
++	int err;
++	struct dentry *diropq;
++
++	err = 0;
++	a->src_bdiropq = au_dbdiropq(a->src_dentry);
++	a->src_hinode = au_hi(a->src_inode, a->btgt);
++	au_hn_imtx_lock_nested(a->src_hinode, AuLsc_I_CHILD);
++	diropq = au_diropq_create(a->src_dentry, a->btgt);
++	au_hn_imtx_unlock(a->src_hinode);
++	if (IS_ERR(diropq))
++		err = PTR_ERR(diropq);
++	else
++		dput(diropq);
++
++	return err;
++}
++
++static int do_rename(struct au_ren_args *a)
++{
++	int err;
++	struct dentry *d, *h_d;
++
++	/* prepare workqueue args for asynchronous rmdir */
++	h_d = a->dst_h_dentry;
++	if (au_ftest_ren(a->flags, ISDIR) && h_d->d_inode) {
++		err = -ENOMEM;
++		a->thargs = au_whtmp_rmdir_alloc(a->src_dentry->d_sb, GFP_NOFS);
++		if (unlikely(!a->thargs))
++			goto out;
++		a->h_dst = dget(h_d);
++	}
++
++	/* create whiteout for src_dentry */
++	if (au_ftest_ren(a->flags, WHSRC)) {
++		a->src_bwh = au_dbwh(a->src_dentry);
++		AuDebugOn(a->src_bwh >= 0);
++		a->src_wh_dentry
++			= au_wh_create(a->src_dentry, a->btgt, a->src_h_parent);
++		err = PTR_ERR(a->src_wh_dentry);
++		if (IS_ERR(a->src_wh_dentry))
++			goto out_thargs;
++	}
++
++	/* lookup whiteout for dentry */
++	if (au_ftest_ren(a->flags, WHDST)) {
++		h_d = au_wh_lkup(a->dst_h_parent, &a->dst_dentry->d_name,
++				 a->br);
++		err = PTR_ERR(h_d);
++		if (IS_ERR(h_d))
++			goto out_whsrc;
++		if (!h_d->d_inode)
++			dput(h_d);
++		else
++			a->dst_wh_dentry = h_d;
++	}
++
++	/* rename dentry to tmpwh */
++	if (a->thargs) {
++		err = au_whtmp_ren(a->dst_h_dentry, a->br);
++		if (unlikely(err))
++			goto out_whdst;
++
++		d = a->dst_dentry;
++		au_set_h_dptr(d, a->btgt, NULL);
++		err = au_lkup_neg(d, a->btgt, /*wh*/0);
++		if (unlikely(err))
++			goto out_whtmp;
++		a->dst_h_dentry = au_h_dptr(d, a->btgt);
++	}
++
++	BUG_ON(a->dst_h_dentry->d_inode && a->src_bstart != a->btgt);
++
++	/* rename by vfs_rename or cpup */
++	d = a->dst_dentry;
++	if (au_ftest_ren(a->flags, ISDIR)
++	    && (a->dst_wh_dentry
++		|| au_dbdiropq(d) == a->btgt
++		/* hide the lower to keep xino */
++		|| a->btgt < au_dbend(d)
++		|| au_opt_test(au_mntflags(d->d_sb), ALWAYS_DIROPQ)))
++		au_fset_ren(a->flags, DIROPQ);
++	err = au_ren_or_cpup(a);
++	if (unlikely(err))
++		/* leave the copied-up one */
++		goto out_whtmp;
++
++	/* make dir opaque */
++	if (au_ftest_ren(a->flags, DIROPQ)) {
++		err = au_ren_diropq(a);
++		if (unlikely(err))
++			goto out_rename;
++	}
++
++	/* update target timestamps */
++	AuDebugOn(au_dbstart(a->src_dentry) != a->btgt);
++	a->h_path.dentry = au_h_dptr(a->src_dentry, a->btgt);
++	vfsub_update_h_iattr(&a->h_path, /*did*/NULL); /*ignore*/
++	a->src_inode->i_ctime = a->h_path.dentry->d_inode->i_ctime;
++
++	/* remove whiteout for dentry */
++	if (a->dst_wh_dentry) {
++		a->h_path.dentry = a->dst_wh_dentry;
++		err = au_wh_unlink_dentry(a->dst_h_dir, &a->h_path,
++					  a->dst_dentry);
++		if (unlikely(err))
++			goto out_diropq;
++	}
++
++	/* remove whtmp */
++	if (a->thargs)
++		au_ren_del_whtmp(a); /* ignore this error */
++
++	au_fhsm_wrote(a->src_dentry->d_sb, a->btgt, /*force*/0);
++	err = 0;
++	goto out_success;
++
++out_diropq:
++	if (au_ftest_ren(a->flags, DIROPQ))
++		au_ren_rev_diropq(err, a);
++out_rename:
++	au_ren_rev_rename(err, a);
++	dput(a->h_dst);
++out_whtmp:
++	if (a->thargs)
++		au_ren_rev_whtmp(err, a);
++out_whdst:
++	dput(a->dst_wh_dentry);
++	a->dst_wh_dentry = NULL;
++out_whsrc:
++	if (a->src_wh_dentry)
++		au_ren_rev_whsrc(err, a);
++out_success:
++	dput(a->src_wh_dentry);
++	dput(a->dst_wh_dentry);
++out_thargs:
++	if (a->thargs) {
++		dput(a->h_dst);
++		au_whtmp_rmdir_free(a->thargs);
++		a->thargs = NULL;
++	}
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * test if @dentry dir can be rename destination or not.
++ * success means, it is a logically empty dir.
++ */
++static int may_rename_dstdir(struct dentry *dentry, struct au_nhash *whlist)
++{
++	return au_test_empty(dentry, whlist);
++}
++
++/*
++ * test if @dentry dir can be rename source or not.
++ * if it can, return 0 and @children is filled.
++ * success means,
++ * - it is a logically empty dir.
++ * - or, it exists on writable branch and has no children including whiteouts
++ *       on the lower branch.
++ */
++static int may_rename_srcdir(struct dentry *dentry, aufs_bindex_t btgt)
++{
++	int err;
++	unsigned int rdhash;
++	aufs_bindex_t bstart;
++
++	bstart = au_dbstart(dentry);
++	if (bstart != btgt) {
++		struct au_nhash whlist;
++
++		SiMustAnyLock(dentry->d_sb);
++		rdhash = au_sbi(dentry->d_sb)->si_rdhash;
++		if (!rdhash)
++			rdhash = au_rdhash_est(au_dir_size(/*file*/NULL,
++							   dentry));
++		err = au_nhash_alloc(&whlist, rdhash, GFP_NOFS);
++		if (unlikely(err))
++			goto out;
++		err = au_test_empty(dentry, &whlist);
++		au_nhash_wh_free(&whlist);
++		goto out;
++	}
++
++	if (bstart == au_dbtaildir(dentry))
++		return 0; /* success */
++
++	err = au_test_empty_lower(dentry);
++
++out:
++	if (err == -ENOTEMPTY) {
++		AuWarn1("renaming dir who has child(ren) on multiple branches,"
++			" is not supported\n");
++		err = -EXDEV;
++	}
++	return err;
++}
++
++/* side effect: sets whlist and h_dentry */
++static int au_ren_may_dir(struct au_ren_args *a)
++{
++	int err;
++	unsigned int rdhash;
++	struct dentry *d;
++
++	d = a->dst_dentry;
++	SiMustAnyLock(d->d_sb);
++
++	err = 0;
++	if (au_ftest_ren(a->flags, ISDIR) && a->dst_inode) {
++		rdhash = au_sbi(d->d_sb)->si_rdhash;
++		if (!rdhash)
++			rdhash = au_rdhash_est(au_dir_size(/*file*/NULL, d));
++		err = au_nhash_alloc(&a->whlist, rdhash, GFP_NOFS);
++		if (unlikely(err))
++			goto out;
++
++		au_set_dbstart(d, a->dst_bstart);
++		err = may_rename_dstdir(d, &a->whlist);
++		au_set_dbstart(d, a->btgt);
++	}
++	a->dst_h_dentry = au_h_dptr(d, au_dbstart(d));
++	if (unlikely(err))
++		goto out;
++
++	d = a->src_dentry;
++	a->src_h_dentry = au_h_dptr(d, au_dbstart(d));
++	if (au_ftest_ren(a->flags, ISDIR)) {
++		err = may_rename_srcdir(d, a->btgt);
++		if (unlikely(err)) {
++			au_nhash_wh_free(&a->whlist);
++			a->whlist.nh_num = 0;
++		}
++	}
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * simple tests for rename.
++ * following the checks in vfs, plus the parent-child relationship.
++ */
++static int au_may_ren(struct au_ren_args *a)
++{
++	int err, isdir;
++	struct inode *h_inode;
++
++	if (a->src_bstart == a->btgt) {
++		err = au_may_del(a->src_dentry, a->btgt, a->src_h_parent,
++				 au_ftest_ren(a->flags, ISDIR));
++		if (unlikely(err))
++			goto out;
++		err = -EINVAL;
++		if (unlikely(a->src_h_dentry == a->h_trap))
++			goto out;
++	}
++
++	err = 0;
++	if (a->dst_bstart != a->btgt)
++		goto out;
++
++	err = -ENOTEMPTY;
++	if (unlikely(a->dst_h_dentry == a->h_trap))
++		goto out;
++
++	err = -EIO;
++	h_inode = a->dst_h_dentry->d_inode;
++	isdir = !!au_ftest_ren(a->flags, ISDIR);
++	if (!a->dst_dentry->d_inode) {
++		if (unlikely(h_inode))
++			goto out;
++		err = au_may_add(a->dst_dentry, a->btgt, a->dst_h_parent,
++				 isdir);
++	} else {
++		if (unlikely(!h_inode || !h_inode->i_nlink))
++			goto out;
++		err = au_may_del(a->dst_dentry, a->btgt, a->dst_h_parent,
++				 isdir);
++		if (unlikely(err))
++			goto out;
++	}
++
++out:
++	if (unlikely(err == -ENOENT || err == -EEXIST))
++		err = -EIO;
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * locking order
++ * (VFS)
++ * - src_dir and dir by lock_rename()
++ * - inode if exitsts
++ * (aufs)
++ * - lock all
++ *   + src_dentry and dentry by aufs_read_and_write_lock2() which calls,
++ *     + si_read_lock
++ *     + di_write_lock2_child()
++ *       + di_write_lock_child()
++ *	   + ii_write_lock_child()
++ *       + di_write_lock_child2()
++ *	   + ii_write_lock_child2()
++ *     + src_parent and parent
++ *       + di_write_lock_parent()
++ *	   + ii_write_lock_parent()
++ *       + di_write_lock_parent2()
++ *	   + ii_write_lock_parent2()
++ *   + lower src_dir and dir by vfsub_lock_rename()
++ *   + verify the every relationships between child and parent. if any
++ *     of them failed, unlock all and return -EBUSY.
++ */
++static void au_ren_unlock(struct au_ren_args *a)
++{
++	vfsub_unlock_rename(a->src_h_parent, a->src_hdir,
++			    a->dst_h_parent, a->dst_hdir);
++	if (au_ftest_ren(a->flags, MNT_WRITE))
++		vfsub_mnt_drop_write(au_br_mnt(a->br));
++}
++
++static int au_ren_lock(struct au_ren_args *a)
++{
++	int err;
++	unsigned int udba;
++
++	err = 0;
++	a->src_h_parent = au_h_dptr(a->src_parent, a->btgt);
++	a->src_hdir = au_hi(a->src_dir, a->btgt);
++	a->dst_h_parent = au_h_dptr(a->dst_parent, a->btgt);
++	a->dst_hdir = au_hi(a->dst_dir, a->btgt);
++
++	err = vfsub_mnt_want_write(au_br_mnt(a->br));
++	if (unlikely(err))
++		goto out;
++	au_fset_ren(a->flags, MNT_WRITE);
++	a->h_trap = vfsub_lock_rename(a->src_h_parent, a->src_hdir,
++				      a->dst_h_parent, a->dst_hdir);
++	udba = au_opt_udba(a->src_dentry->d_sb);
++	if (unlikely(a->src_hdir->hi_inode != a->src_h_parent->d_inode
++		     || a->dst_hdir->hi_inode != a->dst_h_parent->d_inode))
++		err = au_busy_or_stale();
++	if (!err && au_dbstart(a->src_dentry) == a->btgt)
++		err = au_h_verify(a->src_h_dentry, udba,
++				  a->src_h_parent->d_inode, a->src_h_parent,
++				  a->br);
++	if (!err && au_dbstart(a->dst_dentry) == a->btgt)
++		err = au_h_verify(a->dst_h_dentry, udba,
++				  a->dst_h_parent->d_inode, a->dst_h_parent,
++				  a->br);
++	if (!err)
++		goto out; /* success */
++
++	err = au_busy_or_stale();
++	au_ren_unlock(a);
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void au_ren_refresh_dir(struct au_ren_args *a)
++{
++	struct inode *dir;
++
++	dir = a->dst_dir;
++	dir->i_version++;
++	if (au_ftest_ren(a->flags, ISDIR)) {
++		/* is this updating defined in POSIX? */
++		au_cpup_attr_timesizes(a->src_inode);
++		au_cpup_attr_nlink(dir, /*force*/1);
++	}
++
++	au_dir_ts(dir, a->btgt);
++
++	if (au_ftest_ren(a->flags, ISSAMEDIR))
++		return;
++
++	dir = a->src_dir;
++	dir->i_version++;
++	if (au_ftest_ren(a->flags, ISDIR))
++		au_cpup_attr_nlink(dir, /*force*/1);
++	au_dir_ts(dir, a->btgt);
++}
++
++static void au_ren_refresh(struct au_ren_args *a)
++{
++	aufs_bindex_t bend, bindex;
++	struct dentry *d, *h_d;
++	struct inode *i, *h_i;
++	struct super_block *sb;
++
++	d = a->dst_dentry;
++	d_drop(d);
++	if (a->h_dst)
++		/* already dget-ed by au_ren_or_cpup() */
++		au_set_h_dptr(d, a->btgt, a->h_dst);
++
++	i = a->dst_inode;
++	if (i) {
++		if (!au_ftest_ren(a->flags, ISDIR))
++			vfsub_drop_nlink(i);
++		else {
++			vfsub_dead_dir(i);
++			au_cpup_attr_timesizes(i);
++		}
++		au_update_dbrange(d, /*do_put_zero*/1);
++	} else {
++		bend = a->btgt;
++		for (bindex = au_dbstart(d); bindex < bend; bindex++)
++			au_set_h_dptr(d, bindex, NULL);
++		bend = au_dbend(d);
++		for (bindex = a->btgt + 1; bindex <= bend; bindex++)
++			au_set_h_dptr(d, bindex, NULL);
++		au_update_dbrange(d, /*do_put_zero*/0);
++	}
++
++	d = a->src_dentry;
++	au_set_dbwh(d, -1);
++	bend = au_dbend(d);
++	for (bindex = a->btgt + 1; bindex <= bend; bindex++) {
++		h_d = au_h_dptr(d, bindex);
++		if (h_d)
++			au_set_h_dptr(d, bindex, NULL);
++	}
++	au_set_dbend(d, a->btgt);
++
++	sb = d->d_sb;
++	i = a->src_inode;
++	if (au_opt_test(au_mntflags(sb), PLINK) && au_plink_test(i))
++		return; /* success */
++
++	bend = au_ibend(i);
++	for (bindex = a->btgt + 1; bindex <= bend; bindex++) {
++		h_i = au_h_iptr(i, bindex);
++		if (h_i) {
++			au_xino_write(sb, bindex, h_i->i_ino, /*ino*/0);
++			/* ignore this error */
++			au_set_h_iptr(i, bindex, NULL, 0);
++		}
++	}
++	au_set_ibend(i, a->btgt);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* mainly for link(2) and rename(2) */
++int au_wbr(struct dentry *dentry, aufs_bindex_t btgt)
++{
++	aufs_bindex_t bdiropq, bwh;
++	struct dentry *parent;
++	struct au_branch *br;
++
++	parent = dentry->d_parent;
++	IMustLock(parent->d_inode); /* dir is locked */
++
++	bdiropq = au_dbdiropq(parent);
++	bwh = au_dbwh(dentry);
++	br = au_sbr(dentry->d_sb, btgt);
++	if (au_br_rdonly(br)
++	    || (0 <= bdiropq && bdiropq < btgt)
++	    || (0 <= bwh && bwh < btgt))
++		btgt = -1;
++
++	AuDbg("btgt %d\n", btgt);
++	return btgt;
++}
++
++/* sets src_bstart, dst_bstart and btgt */
++static int au_ren_wbr(struct au_ren_args *a)
++{
++	int err;
++	struct au_wr_dir_args wr_dir_args = {
++		/* .force_btgt	= -1, */
++		.flags		= AuWrDir_ADD_ENTRY
++	};
++
++	a->src_bstart = au_dbstart(a->src_dentry);
++	a->dst_bstart = au_dbstart(a->dst_dentry);
++	if (au_ftest_ren(a->flags, ISDIR))
++		au_fset_wrdir(wr_dir_args.flags, ISDIR);
++	wr_dir_args.force_btgt = a->src_bstart;
++	if (a->dst_inode && a->dst_bstart < a->src_bstart)
++		wr_dir_args.force_btgt = a->dst_bstart;
++	wr_dir_args.force_btgt = au_wbr(a->dst_dentry, wr_dir_args.force_btgt);
++	err = au_wr_dir(a->dst_dentry, a->src_dentry, &wr_dir_args);
++	a->btgt = err;
++
++	return err;
++}
++
++static void au_ren_dt(struct au_ren_args *a)
++{
++	a->h_path.dentry = a->src_h_parent;
++	au_dtime_store(a->src_dt + AuPARENT, a->src_parent, &a->h_path);
++	if (!au_ftest_ren(a->flags, ISSAMEDIR)) {
++		a->h_path.dentry = a->dst_h_parent;
++		au_dtime_store(a->dst_dt + AuPARENT, a->dst_parent, &a->h_path);
++	}
++
++	au_fclr_ren(a->flags, DT_DSTDIR);
++	if (!au_ftest_ren(a->flags, ISDIR))
++		return;
++
++	a->h_path.dentry = a->src_h_dentry;
++	au_dtime_store(a->src_dt + AuCHILD, a->src_dentry, &a->h_path);
++	if (a->dst_h_dentry->d_inode) {
++		au_fset_ren(a->flags, DT_DSTDIR);
++		a->h_path.dentry = a->dst_h_dentry;
++		au_dtime_store(a->dst_dt + AuCHILD, a->dst_dentry, &a->h_path);
++	}
++}
++
++static void au_ren_rev_dt(int err, struct au_ren_args *a)
++{
++	struct dentry *h_d;
++	struct mutex *h_mtx;
++
++	au_dtime_revert(a->src_dt + AuPARENT);
++	if (!au_ftest_ren(a->flags, ISSAMEDIR))
++		au_dtime_revert(a->dst_dt + AuPARENT);
++
++	if (au_ftest_ren(a->flags, ISDIR) && err != -EIO) {
++		h_d = a->src_dt[AuCHILD].dt_h_path.dentry;
++		h_mtx = &h_d->d_inode->i_mutex;
++		mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++		au_dtime_revert(a->src_dt + AuCHILD);
++		mutex_unlock(h_mtx);
++
++		if (au_ftest_ren(a->flags, DT_DSTDIR)) {
++			h_d = a->dst_dt[AuCHILD].dt_h_path.dentry;
++			h_mtx = &h_d->d_inode->i_mutex;
++			mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
++			au_dtime_revert(a->dst_dt + AuCHILD);
++			mutex_unlock(h_mtx);
++		}
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++int aufs_rename(struct inode *_src_dir, struct dentry *_src_dentry,
++		struct inode *_dst_dir, struct dentry *_dst_dentry)
++{
++	int err, flags;
++	/* reduce stack space */
++	struct au_ren_args *a;
++
++	AuDbg("%pd, %pd\n", _src_dentry, _dst_dentry);
++	IMustLock(_src_dir);
++	IMustLock(_dst_dir);
++
++	err = -ENOMEM;
++	BUILD_BUG_ON(sizeof(*a) > PAGE_SIZE);
++	a = kzalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	a->src_dir = _src_dir;
++	a->src_dentry = _src_dentry;
++	a->src_inode = a->src_dentry->d_inode;
++	a->src_parent = a->src_dentry->d_parent; /* dir inode is locked */
++	a->dst_dir = _dst_dir;
++	a->dst_dentry = _dst_dentry;
++	a->dst_inode = a->dst_dentry->d_inode;
++	a->dst_parent = a->dst_dentry->d_parent; /* dir inode is locked */
++	if (a->dst_inode) {
++		IMustLock(a->dst_inode);
++		au_igrab(a->dst_inode);
++	}
++
++	err = -ENOTDIR;
++	flags = AuLock_FLUSH | AuLock_NOPLM | AuLock_GEN;
++	if (d_is_dir(a->src_dentry)) {
++		au_fset_ren(a->flags, ISDIR);
++		if (unlikely(d_is_positive(a->dst_dentry)
++			     && !d_is_dir(a->dst_dentry)))
++			goto out_free;
++		err = aufs_read_and_write_lock2(a->dst_dentry, a->src_dentry,
++						AuLock_DIR | flags);
++	} else
++		err = aufs_read_and_write_lock2(a->dst_dentry, a->src_dentry,
++						flags);
++	if (unlikely(err))
++		goto out_free;
++
++	err = au_d_hashed_positive(a->src_dentry);
++	if (unlikely(err))
++		goto out_unlock;
++	err = -ENOENT;
++	if (a->dst_inode) {
++		/*
++		 * If it is a dir, VFS unhash dst_dentry before this
++		 * function. It means we cannot rely upon d_unhashed().
++		 */
++		if (unlikely(!a->dst_inode->i_nlink))
++			goto out_unlock;
++		if (!S_ISDIR(a->dst_inode->i_mode)) {
++			err = au_d_hashed_positive(a->dst_dentry);
++			if (unlikely(err))
++				goto out_unlock;
++		} else if (unlikely(IS_DEADDIR(a->dst_inode)))
++			goto out_unlock;
++	} else if (unlikely(d_unhashed(a->dst_dentry)))
++		goto out_unlock;
++
++	/*
++	 * is it possible?
++	 * yes, it happend (in linux-3.3-rcN) but I don't know why.
++	 * there may exist a problem somewhere else.
++	 */
++	err = -EINVAL;
++	if (unlikely(a->dst_parent->d_inode == a->src_dentry->d_inode))
++		goto out_unlock;
++
++	au_fset_ren(a->flags, ISSAMEDIR); /* temporary */
++	di_write_lock_parent(a->dst_parent);
++
++	/* which branch we process */
++	err = au_ren_wbr(a);
++	if (unlikely(err < 0))
++		goto out_parent;
++	a->br = au_sbr(a->dst_dentry->d_sb, a->btgt);
++	a->h_path.mnt = au_br_mnt(a->br);
++
++	/* are they available to be renamed */
++	err = au_ren_may_dir(a);
++	if (unlikely(err))
++		goto out_children;
++
++	/* prepare the writable parent dir on the same branch */
++	if (a->dst_bstart == a->btgt) {
++		au_fset_ren(a->flags, WHDST);
++	} else {
++		err = au_cpup_dirs(a->dst_dentry, a->btgt);
++		if (unlikely(err))
++			goto out_children;
++	}
++
++	if (a->src_dir != a->dst_dir) {
++		/*
++		 * this temporary unlock is safe,
++		 * because both dir->i_mutex are locked.
++		 */
++		di_write_unlock(a->dst_parent);
++		di_write_lock_parent(a->src_parent);
++		err = au_wr_dir_need_wh(a->src_dentry,
++					au_ftest_ren(a->flags, ISDIR),
++					&a->btgt);
++		di_write_unlock(a->src_parent);
++		di_write_lock2_parent(a->src_parent, a->dst_parent, /*isdir*/1);
++		au_fclr_ren(a->flags, ISSAMEDIR);
++	} else
++		err = au_wr_dir_need_wh(a->src_dentry,
++					au_ftest_ren(a->flags, ISDIR),
++					&a->btgt);
++	if (unlikely(err < 0))
++		goto out_children;
++	if (err)
++		au_fset_ren(a->flags, WHSRC);
++
++	/* cpup src */
++	if (a->src_bstart != a->btgt) {
++		struct au_pin pin;
++
++		err = au_pin(&pin, a->src_dentry, a->btgt,
++			     au_opt_udba(a->src_dentry->d_sb),
++			     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
++		if (!err) {
++			struct au_cp_generic cpg = {
++				.dentry	= a->src_dentry,
++				.bdst	= a->btgt,
++				.bsrc	= a->src_bstart,
++				.len	= -1,
++				.pin	= &pin,
++				.flags	= AuCpup_DTIME | AuCpup_HOPEN
++			};
++			AuDebugOn(au_dbstart(a->src_dentry) != a->src_bstart);
++			err = au_sio_cpup_simple(&cpg);
++			au_unpin(&pin);
++		}
++		if (unlikely(err))
++			goto out_children;
++		a->src_bstart = a->btgt;
++		a->src_h_dentry = au_h_dptr(a->src_dentry, a->btgt);
++		au_fset_ren(a->flags, WHSRC);
++	}
++
++	/* lock them all */
++	err = au_ren_lock(a);
++	if (unlikely(err))
++		/* leave the copied-up one */
++		goto out_children;
++
++	if (!au_opt_test(au_mntflags(a->dst_dir->i_sb), UDBA_NONE))
++		err = au_may_ren(a);
++	else if (unlikely(a->dst_dentry->d_name.len > AUFS_MAX_NAMELEN))
++		err = -ENAMETOOLONG;
++	if (unlikely(err))
++		goto out_hdir;
++
++	/* store timestamps to be revertible */
++	au_ren_dt(a);
++
++	/* here we go */
++	err = do_rename(a);
++	if (unlikely(err))
++		goto out_dt;
++
++	/* update dir attributes */
++	au_ren_refresh_dir(a);
++
++	/* dput/iput all lower dentries */
++	au_ren_refresh(a);
++
++	goto out_hdir; /* success */
++
++out_dt:
++	au_ren_rev_dt(err, a);
++out_hdir:
++	au_ren_unlock(a);
++out_children:
++	au_nhash_wh_free(&a->whlist);
++	if (err && a->dst_inode && a->dst_bstart != a->btgt) {
++		AuDbg("bstart %d, btgt %d\n", a->dst_bstart, a->btgt);
++		au_set_h_dptr(a->dst_dentry, a->btgt, NULL);
++		au_set_dbstart(a->dst_dentry, a->dst_bstart);
++	}
++out_parent:
++	if (!err)
++		d_move(a->src_dentry, a->dst_dentry);
++	else {
++		au_update_dbstart(a->dst_dentry);
++		if (!a->dst_inode)
++			d_drop(a->dst_dentry);
++	}
++	if (au_ftest_ren(a->flags, ISSAMEDIR))
++		di_write_unlock(a->dst_parent);
++	else
++		di_write_unlock2(a->src_parent, a->dst_parent);
++out_unlock:
++	aufs_read_and_write_unlock2(a->dst_dentry, a->src_dentry);
++out_free:
++	iput(a->dst_inode);
++	if (a->thargs)
++		au_whtmp_rmdir_free(a->thargs);
++	kfree(a);
++out:
++	AuTraceErr(err);
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/Kconfig linux-4.0.4/fs/aufs/Kconfig
+--- linux-4.0.4.orig/fs/aufs/Kconfig	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/Kconfig	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,185 @@
++config AUFS_FS
++	bool "Aufs (Advanced multi layered unification filesystem) support"
++	help
++	Aufs is a stackable unification filesystem such as Unionfs,
++	which unifies several directories and provides a merged single
++	directory.
++	In the early days, aufs was entirely re-designed and
++	re-implemented Unionfs Version 1.x series. Introducing many
++	original ideas, approaches and improvements, it becomes totally
++	different from Unionfs while keeping the basic features.
++
++if AUFS_FS
++choice
++	prompt "Maximum number of branches"
++	default AUFS_BRANCH_MAX_127
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++config AUFS_BRANCH_MAX_127
++	bool "127"
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++config AUFS_BRANCH_MAX_511
++	bool "511"
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++config AUFS_BRANCH_MAX_1023
++	bool "1023"
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++config AUFS_BRANCH_MAX_32767
++	bool "32767"
++	help
++	Specifies the maximum number of branches (or member directories)
++	in a single aufs. The larger value consumes more system
++	resources and has a minor impact to performance.
++endchoice
++
++config AUFS_SBILIST
++	bool
++	depends on AUFS_MAGIC_SYSRQ || PROC_FS
++	default y
++	help
++	Automatic configuration for internal use.
++	When aufs supports Magic SysRq or /proc, enabled automatically.
++
++config AUFS_HNOTIFY
++	bool "Detect direct branch access (bypassing aufs)"
++	help
++	If you want to modify files on branches directly, eg. bypassing aufs,
++	and want aufs to detect the changes of them fully, then enable this
++	option and use 'udba=notify' mount option.
++	Currently there is only one available configuration, "fsnotify".
++	It will have a negative impact to the performance.
++	See detail in aufs.5.
++
++choice
++	prompt "method" if AUFS_HNOTIFY
++	default AUFS_HFSNOTIFY
++config AUFS_HFSNOTIFY
++	bool "fsnotify"
++	select FSNOTIFY
++endchoice
++
++config AUFS_EXPORT
++	bool "NFS-exportable aufs"
++	depends on EXPORTFS = y
++	help
++	If you want to export your mounted aufs via NFS, then enable this
++	option. There are several requirements for this configuration.
++	See detail in aufs.5.
++
++config AUFS_INO_T_64
++	bool
++	depends on AUFS_EXPORT
++	depends on 64BIT && !(ALPHA || S390)
++	default y
++	help
++	Automatic configuration for internal use.
++	/* typedef unsigned long/int __kernel_ino_t */
++	/* alpha and s390x are int */
++
++config AUFS_XATTR
++	bool "support for XATTR/EA (including Security Labels)"
++	help
++	If your branch fs supports XATTR/EA and you want to make them
++	available in aufs too, then enable this opsion and specify the
++	branch attributes for EA.
++	See detail in aufs.5.
++
++config AUFS_FHSM
++	bool "File-based Hierarchical Storage Management"
++	help
++	Hierarchical Storage Management (or HSM) is a well-known feature
++	in the storage world. Aufs provides this feature as file-based.
++	with multiple branches.
++	These multiple branches are prioritized, ie. the topmost one
++	should be the fastest drive and be used heavily.
++
++config AUFS_RDU
++	bool "Readdir in userspace"
++	help
++	Aufs has two methods to provide a merged view for a directory,
++	by a user-space library and by kernel-space natively. The latter
++	is always enabled but sometimes large and slow.
++	If you enable this option, install the library in aufs2-util
++	package, and set some environment variables for your readdir(3),
++	then the work will be handled in user-space which generally
++	shows better performance in most cases.
++	See detail in aufs.5.
++
++config AUFS_SHWH
++	bool "Show whiteouts"
++	help
++	If you want to make the whiteouts in aufs visible, then enable
++	this option and specify 'shwh' mount option. Although it may
++	sounds like philosophy or something, but in technically it
++	simply shows the name of whiteout with keeping its behaviour.
++
++config AUFS_BR_RAMFS
++	bool "Ramfs (initramfs/rootfs) as an aufs branch"
++	help
++	If you want to use ramfs as an aufs branch fs, then enable this
++	option. Generally tmpfs is recommended.
++	Aufs prohibited them to be a branch fs by default, because
++	initramfs becomes unusable after switch_root or something
++	generally. If you sets initramfs as an aufs branch and boot your
++	system by switch_root, you will meet a problem easily since the
++	files in initramfs may be inaccessible.
++	Unless you are going to use ramfs as an aufs branch fs without
++	switch_root or something, leave it N.
++
++config AUFS_BR_FUSE
++	bool "Fuse fs as an aufs branch"
++	depends on FUSE_FS
++	select AUFS_POLL
++	help
++	If you want to use fuse-based userspace filesystem as an aufs
++	branch fs, then enable this option.
++	It implements the internal poll(2) operation which is
++	implemented by fuse only (curretnly).
++
++config AUFS_POLL
++	bool
++	help
++	Automatic configuration for internal use.
++
++config AUFS_BR_HFSPLUS
++	bool "Hfsplus as an aufs branch"
++	depends on HFSPLUS_FS
++	default y
++	help
++	If you want to use hfsplus fs as an aufs branch fs, then enable
++	this option. This option introduces a small overhead at
++	copying-up a file on hfsplus.
++
++config AUFS_BDEV_LOOP
++	bool
++	depends on BLK_DEV_LOOP
++	default y
++	help
++	Automatic configuration for internal use.
++	Convert =[ym] into =y.
++
++config AUFS_DEBUG
++	bool "Debug aufs"
++	help
++	Enable this to compile aufs internal debug code.
++	It will have a negative impact to the performance.
++
++config AUFS_MAGIC_SYSRQ
++	bool
++	depends on AUFS_DEBUG && MAGIC_SYSRQ
++	default y
++	help
++	Automatic configuration for internal use.
++	When aufs supports Magic SysRq, enabled automatically.
++endif
+diff -Nur linux-4.0.4.orig/fs/aufs/loop.c linux-4.0.4/fs/aufs/loop.c
+--- linux-4.0.4.orig/fs/aufs/loop.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/loop.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,132 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * support for loopback block device as a branch
++ */
++
++#include "aufs.h"
++
++/* added into drivers/block/loop.c */
++static struct file *(*backing_file_func)(struct super_block *sb);
++
++/*
++ * test if two lower dentries have overlapping branches.
++ */
++int au_test_loopback_overlap(struct super_block *sb, struct dentry *h_adding)
++{
++	struct super_block *h_sb;
++	struct file *backing_file;
++
++	if (unlikely(!backing_file_func)) {
++		/* don't load "loop" module here */
++		backing_file_func = symbol_get(loop_backing_file);
++		if (unlikely(!backing_file_func))
++			/* "loop" module is not loaded */
++			return 0;
++	}
++
++	h_sb = h_adding->d_sb;
++	backing_file = backing_file_func(h_sb);
++	if (!backing_file)
++		return 0;
++
++	h_adding = backing_file->f_path.dentry;
++	/*
++	 * h_adding can be local NFS.
++	 * in this case aufs cannot detect the loop.
++	 */
++	if (unlikely(h_adding->d_sb == sb))
++		return 1;
++	return !!au_test_subdir(h_adding, sb->s_root);
++}
++
++/* true if a kernel thread named 'loop[0-9].*' accesses a file */
++int au_test_loopback_kthread(void)
++{
++	int ret;
++	struct task_struct *tsk = current;
++	char c, comm[sizeof(tsk->comm)];
++
++	ret = 0;
++	if (tsk->flags & PF_KTHREAD) {
++		get_task_comm(comm, tsk);
++		c = comm[4];
++		ret = ('0' <= c && c <= '9'
++		       && !strncmp(comm, "loop", 4));
++	}
++
++	return ret;
++}
++
++/* ---------------------------------------------------------------------- */
++
++#define au_warn_loopback_step	16
++static int au_warn_loopback_nelem = au_warn_loopback_step;
++static unsigned long *au_warn_loopback_array;
++
++void au_warn_loopback(struct super_block *h_sb)
++{
++	int i, new_nelem;
++	unsigned long *a, magic;
++	static DEFINE_SPINLOCK(spin);
++
++	magic = h_sb->s_magic;
++	spin_lock(&spin);
++	a = au_warn_loopback_array;
++	for (i = 0; i < au_warn_loopback_nelem && *a; i++)
++		if (a[i] == magic) {
++			spin_unlock(&spin);
++			return;
++		}
++
++	/* h_sb is new to us, print it */
++	if (i < au_warn_loopback_nelem) {
++		a[i] = magic;
++		goto pr;
++	}
++
++	/* expand the array */
++	new_nelem = au_warn_loopback_nelem + au_warn_loopback_step;
++	a = au_kzrealloc(au_warn_loopback_array,
++			 au_warn_loopback_nelem * sizeof(unsigned long),
++			 new_nelem * sizeof(unsigned long), GFP_ATOMIC);
++	if (a) {
++		au_warn_loopback_nelem = new_nelem;
++		au_warn_loopback_array = a;
++		a[i] = magic;
++		goto pr;
++	}
++
++	spin_unlock(&spin);
++	AuWarn1("realloc failed, ignored\n");
++	return;
++
++pr:
++	spin_unlock(&spin);
++	pr_warn("you may want to try another patch for loopback file "
++		"on %s(0x%lx) branch\n", au_sbtype(h_sb), magic);
++}
++
++int au_loopback_init(void)
++{
++	int err;
++	struct super_block *sb __maybe_unused;
++
++	AuDebugOn(sizeof(sb->s_magic) != sizeof(unsigned long));
++
++	err = 0;
++	au_warn_loopback_array = kcalloc(au_warn_loopback_step,
++					 sizeof(unsigned long), GFP_NOFS);
++	if (unlikely(!au_warn_loopback_array))
++		err = -ENOMEM;
++
++	return err;
++}
++
++void au_loopback_fin(void)
++{
++	symbol_put(loop_backing_file);
++	kfree(au_warn_loopback_array);
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/loop.h linux-4.0.4/fs/aufs/loop.h
+--- linux-4.0.4.orig/fs/aufs/loop.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/loop.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,39 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * support for loopback mount as a branch
++ */
++
++#ifndef __AUFS_LOOP_H__
++#define __AUFS_LOOP_H__
++
++#ifdef __KERNEL__
++
++struct dentry;
++struct super_block;
++
++#ifdef CONFIG_AUFS_BDEV_LOOP
++/* drivers/block/loop.c */
++struct file *loop_backing_file(struct super_block *sb);
++
++/* loop.c */
++int au_test_loopback_overlap(struct super_block *sb, struct dentry *h_adding);
++int au_test_loopback_kthread(void);
++void au_warn_loopback(struct super_block *h_sb);
++
++int au_loopback_init(void);
++void au_loopback_fin(void);
++#else
++AuStubInt0(au_test_loopback_overlap, struct super_block *sb,
++	   struct dentry *h_adding)
++AuStubInt0(au_test_loopback_kthread, void)
++AuStubVoid(au_warn_loopback, struct super_block *h_sb)
++
++AuStubInt0(au_loopback_init, void)
++AuStubVoid(au_loopback_fin, void)
++#endif /* BLK_DEV_LOOP */
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_LOOP_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/magic.mk linux-4.0.4/fs/aufs/magic.mk
+--- linux-4.0.4.orig/fs/aufs/magic.mk	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/magic.mk	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,30 @@
++
++# defined in ${srctree}/fs/fuse/inode.c
++# tristate
++ifdef CONFIG_FUSE_FS
++ccflags-y += -DFUSE_SUPER_MAGIC=0x65735546
++endif
++
++# defined in ${srctree}/fs/xfs/xfs_sb.h
++# tristate
++ifdef CONFIG_XFS_FS
++ccflags-y += -DXFS_SB_MAGIC=0x58465342
++endif
++
++# defined in ${srctree}/fs/configfs/mount.c
++# tristate
++ifdef CONFIG_CONFIGFS_FS
++ccflags-y += -DCONFIGFS_MAGIC=0x62656570
++endif
++
++# defined in ${srctree}/fs/ubifs/ubifs.h
++# tristate
++ifdef CONFIG_UBIFS_FS
++ccflags-y += -DUBIFS_SUPER_MAGIC=0x24051905
++endif
++
++# defined in ${srctree}/fs/hfsplus/hfsplus_raw.h
++# tristate
++ifdef CONFIG_HFSPLUS_FS
++ccflags-y += -DHFSPLUS_SUPER_MAGIC=0x482b
++endif
+diff -Nur linux-4.0.4.orig/fs/aufs/Makefile linux-4.0.4/fs/aufs/Makefile
+--- linux-4.0.4.orig/fs/aufs/Makefile	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/Makefile	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,36 @@
++
++include ${srctree}/${src}/magic.mk
++
++# cf. include/linux/kernel.h
++# enable pr_debug
++ccflags-y += -DDEBUG
++# sparse requires the full pathname
++ccflags-y += -include ${srctree}/include/uapi/linux/aufs_type.h
++
++obj-$(CONFIG_AUFS_FS) += aufs.o
++aufs-y := module.o sbinfo.o super.o branch.o xino.o sysaufs.o opts.o \
++	wkq.o vfsub.o dcsub.o \
++	cpup.o whout.o wbr_policy.o \
++	dinfo.o dentry.o \
++	dynop.o \
++	finfo.o file.o f_op.o \
++	dir.o vdir.o \
++	iinfo.o inode.o i_op.o i_op_add.o i_op_del.o i_op_ren.o \
++	mvdown.o ioctl.o
++
++# all are boolean
++aufs-$(CONFIG_PROC_FS) += procfs.o plink.o
++aufs-$(CONFIG_SYSFS) += sysfs.o
++aufs-$(CONFIG_DEBUG_FS) += dbgaufs.o
++aufs-$(CONFIG_AUFS_BDEV_LOOP) += loop.o
++aufs-$(CONFIG_AUFS_HNOTIFY) += hnotify.o
++aufs-$(CONFIG_AUFS_HFSNOTIFY) += hfsnotify.o
++aufs-$(CONFIG_AUFS_EXPORT) += export.o
++aufs-$(CONFIG_AUFS_XATTR) += xattr.o
++aufs-$(CONFIG_FS_POSIX_ACL) += posix_acl.o
++aufs-$(CONFIG_AUFS_FHSM) += fhsm.o
++aufs-$(CONFIG_AUFS_POLL) += poll.o
++aufs-$(CONFIG_AUFS_RDU) += rdu.o
++aufs-$(CONFIG_AUFS_BR_HFSPLUS) += hfsplus.o
++aufs-$(CONFIG_AUFS_DEBUG) += debug.o
++aufs-$(CONFIG_AUFS_MAGIC_SYSRQ) += sysrq.o
+diff -Nur linux-4.0.4.orig/fs/aufs/module.c linux-4.0.4/fs/aufs/module.c
+--- linux-4.0.4.orig/fs/aufs/module.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/module.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,196 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * module global variables and operations
++ */
++
++#include <linux/module.h>
++#include <linux/seq_file.h>
++#include "aufs.h"
++
++void *au_kzrealloc(void *p, unsigned int nused, unsigned int new_sz, gfp_t gfp)
++{
++	if (new_sz <= nused)
++		return p;
++
++	p = krealloc(p, new_sz, gfp);
++	if (p)
++		memset(p + nused, 0, new_sz - nused);
++	return p;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * aufs caches
++ */
++struct kmem_cache *au_cachep[AuCache_Last];
++static int __init au_cache_init(void)
++{
++	au_cachep[AuCache_DINFO] = AuCacheCtor(au_dinfo, au_di_init_once);
++	if (au_cachep[AuCache_DINFO])
++		/* SLAB_DESTROY_BY_RCU */
++		au_cachep[AuCache_ICNTNR] = AuCacheCtor(au_icntnr,
++							au_icntnr_init_once);
++	if (au_cachep[AuCache_ICNTNR])
++		au_cachep[AuCache_FINFO] = AuCacheCtor(au_finfo,
++						       au_fi_init_once);
++	if (au_cachep[AuCache_FINFO])
++		au_cachep[AuCache_VDIR] = AuCache(au_vdir);
++	if (au_cachep[AuCache_VDIR])
++		au_cachep[AuCache_DEHSTR] = AuCache(au_vdir_dehstr);
++	if (au_cachep[AuCache_DEHSTR])
++		return 0;
++
++	return -ENOMEM;
++}
++
++static void au_cache_fin(void)
++{
++	int i;
++
++	/*
++	 * Make sure all delayed rcu free inodes are flushed before we
++	 * destroy cache.
++	 */
++	rcu_barrier();
++
++	/* excluding AuCache_HNOTIFY */
++	BUILD_BUG_ON(AuCache_HNOTIFY + 1 != AuCache_Last);
++	for (i = 0; i < AuCache_HNOTIFY; i++)
++		if (au_cachep[i]) {
++			kmem_cache_destroy(au_cachep[i]);
++			au_cachep[i] = NULL;
++		}
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_dir_roflags;
++
++#ifdef CONFIG_AUFS_SBILIST
++/*
++ * iterate_supers_type() doesn't protect us from
++ * remounting (branch management)
++ */
++struct au_splhead au_sbilist;
++#endif
++
++struct lock_class_key au_lc_key[AuLcKey_Last];
++
++/*
++ * functions for module interface.
++ */
++MODULE_LICENSE("GPL");
++/* MODULE_LICENSE("GPL v2"); */
++MODULE_AUTHOR("Junjiro R. Okajima <aufs-users@lists.sourceforge.net>");
++MODULE_DESCRIPTION(AUFS_NAME
++	" -- Advanced multi layered unification filesystem");
++MODULE_VERSION(AUFS_VERSION);
++
++/* this module parameter has no meaning when SYSFS is disabled */
++int sysaufs_brs = 1;
++MODULE_PARM_DESC(brs, "use <sysfs>/fs/aufs/si_*/brN");
++module_param_named(brs, sysaufs_brs, int, S_IRUGO);
++
++/* this module parameter has no meaning when USER_NS is disabled */
++static bool au_userns;
++MODULE_PARM_DESC(allow_userns, "allow unprivileged to mount under userns");
++module_param_named(allow_userns, au_userns, bool, S_IRUGO);
++
++/* ---------------------------------------------------------------------- */
++
++static char au_esc_chars[0x20 + 3]; /* 0x01-0x20, backslash, del, and NULL */
++
++int au_seq_path(struct seq_file *seq, struct path *path)
++{
++	return seq_path(seq, path, au_esc_chars);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int __init aufs_init(void)
++{
++	int err, i;
++	char *p;
++
++	p = au_esc_chars;
++	for (i = 1; i <= ' '; i++)
++		*p++ = i;
++	*p++ = '\\';
++	*p++ = '\x7f';
++	*p = 0;
++
++	au_dir_roflags = au_file_roflags(O_DIRECTORY | O_LARGEFILE);
++
++	au_sbilist_init();
++	sysaufs_brs_init();
++	au_debug_init();
++	au_dy_init();
++	err = sysaufs_init();
++	if (unlikely(err))
++		goto out;
++	err = au_procfs_init();
++	if (unlikely(err))
++		goto out_sysaufs;
++	err = au_wkq_init();
++	if (unlikely(err))
++		goto out_procfs;
++	err = au_loopback_init();
++	if (unlikely(err))
++		goto out_wkq;
++	err = au_hnotify_init();
++	if (unlikely(err))
++		goto out_loopback;
++	err = au_sysrq_init();
++	if (unlikely(err))
++		goto out_hin;
++	err = au_cache_init();
++	if (unlikely(err))
++		goto out_sysrq;
++
++	aufs_fs_type.fs_flags |= au_userns ? FS_USERNS_MOUNT : 0;
++	err = register_filesystem(&aufs_fs_type);
++	if (unlikely(err))
++		goto out_cache;
++
++	/* since we define pr_fmt, call printk directly */
++	printk(KERN_INFO AUFS_NAME " " AUFS_VERSION "\n");
++	goto out; /* success */
++
++out_cache:
++	au_cache_fin();
++out_sysrq:
++	au_sysrq_fin();
++out_hin:
++	au_hnotify_fin();
++out_loopback:
++	au_loopback_fin();
++out_wkq:
++	au_wkq_fin();
++out_procfs:
++	au_procfs_fin();
++out_sysaufs:
++	sysaufs_fin();
++	au_dy_fin();
++out:
++	return err;
++}
++
++static void __exit aufs_exit(void)
++{
++	unregister_filesystem(&aufs_fs_type);
++	au_cache_fin();
++	au_sysrq_fin();
++	au_hnotify_fin();
++	au_loopback_fin();
++	au_wkq_fin();
++	au_procfs_fin();
++	sysaufs_fin();
++	au_dy_fin();
++}
++
++module_init(aufs_init);
++module_exit(aufs_exit);
+diff -Nur linux-4.0.4.orig/fs/aufs/module.h linux-4.0.4/fs/aufs/module.h
+--- linux-4.0.4.orig/fs/aufs/module.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/module.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,91 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * module initialization and module-global
++ */
++
++#ifndef __AUFS_MODULE_H__
++#define __AUFS_MODULE_H__
++
++#ifdef __KERNEL__
++
++#include <linux/slab.h>
++
++struct path;
++struct seq_file;
++
++/* module parameters */
++extern int sysaufs_brs;
++
++/* ---------------------------------------------------------------------- */
++
++extern int au_dir_roflags;
++
++enum {
++	AuLcNonDir_FIINFO,
++	AuLcNonDir_DIINFO,
++	AuLcNonDir_IIINFO,
++
++	AuLcDir_FIINFO,
++	AuLcDir_DIINFO,
++	AuLcDir_IIINFO,
++
++	AuLcSymlink_DIINFO,
++	AuLcSymlink_IIINFO,
++
++	AuLcKey_Last
++};
++extern struct lock_class_key au_lc_key[AuLcKey_Last];
++
++void *au_kzrealloc(void *p, unsigned int nused, unsigned int new_sz, gfp_t gfp);
++int au_seq_path(struct seq_file *seq, struct path *path);
++
++#ifdef CONFIG_PROC_FS
++/* procfs.c */
++int __init au_procfs_init(void);
++void au_procfs_fin(void);
++#else
++AuStubInt0(au_procfs_init, void);
++AuStubVoid(au_procfs_fin, void);
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++/* kmem cache */
++enum {
++	AuCache_DINFO,
++	AuCache_ICNTNR,
++	AuCache_FINFO,
++	AuCache_VDIR,
++	AuCache_DEHSTR,
++	AuCache_HNOTIFY, /* must be last */
++	AuCache_Last
++};
++
++#define AuCacheFlags		(SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD)
++#define AuCache(type)		KMEM_CACHE(type, AuCacheFlags)
++#define AuCacheCtor(type, ctor)	\
++	kmem_cache_create(#type, sizeof(struct type), \
++			  __alignof__(struct type), AuCacheFlags, ctor)
++
++extern struct kmem_cache *au_cachep[];
++
++#define AuCacheFuncs(name, index) \
++static inline struct au_##name *au_cache_alloc_##name(void) \
++{ return kmem_cache_alloc(au_cachep[AuCache_##index], GFP_NOFS); } \
++static inline void au_cache_free_##name(struct au_##name *p) \
++{ kmem_cache_free(au_cachep[AuCache_##index], p); }
++
++AuCacheFuncs(dinfo, DINFO);
++AuCacheFuncs(icntnr, ICNTNR);
++AuCacheFuncs(finfo, FINFO);
++AuCacheFuncs(vdir, VDIR);
++AuCacheFuncs(vdir_dehstr, DEHSTR);
++#ifdef CONFIG_AUFS_HNOTIFY
++AuCacheFuncs(hnotify, HNOTIFY);
++#endif
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_MODULE_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/mvdown.c linux-4.0.4/fs/aufs/mvdown.c
+--- linux-4.0.4.orig/fs/aufs/mvdown.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/mvdown.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,681 @@
++/*
++ * Copyright (C) 2011-2015 Junjiro R. Okajima
++ */
++
++/*
++ * move-down, opposite of copy-up
++ */
++
++#include "aufs.h"
++
++struct au_mvd_args {
++	struct {
++		struct super_block *h_sb;
++		struct dentry *h_parent;
++		struct au_hinode *hdir;
++		struct inode *h_dir, *h_inode;
++		struct au_pin pin;
++	} info[AUFS_MVDOWN_NARRAY];
++
++	struct aufs_mvdown mvdown;
++	struct dentry *dentry, *parent;
++	struct inode *inode, *dir;
++	struct super_block *sb;
++	aufs_bindex_t bopq, bwh, bfound;
++	unsigned char rename_lock;
++};
++
++#define mvd_errno		mvdown.au_errno
++#define mvd_bsrc		mvdown.stbr[AUFS_MVDOWN_UPPER].bindex
++#define mvd_src_brid		mvdown.stbr[AUFS_MVDOWN_UPPER].brid
++#define mvd_bdst		mvdown.stbr[AUFS_MVDOWN_LOWER].bindex
++#define mvd_dst_brid		mvdown.stbr[AUFS_MVDOWN_LOWER].brid
++
++#define mvd_h_src_sb		info[AUFS_MVDOWN_UPPER].h_sb
++#define mvd_h_src_parent	info[AUFS_MVDOWN_UPPER].h_parent
++#define mvd_hdir_src		info[AUFS_MVDOWN_UPPER].hdir
++#define mvd_h_src_dir		info[AUFS_MVDOWN_UPPER].h_dir
++#define mvd_h_src_inode		info[AUFS_MVDOWN_UPPER].h_inode
++#define mvd_pin_src		info[AUFS_MVDOWN_UPPER].pin
++
++#define mvd_h_dst_sb		info[AUFS_MVDOWN_LOWER].h_sb
++#define mvd_h_dst_parent	info[AUFS_MVDOWN_LOWER].h_parent
++#define mvd_hdir_dst		info[AUFS_MVDOWN_LOWER].hdir
++#define mvd_h_dst_dir		info[AUFS_MVDOWN_LOWER].h_dir
++#define mvd_h_dst_inode		info[AUFS_MVDOWN_LOWER].h_inode
++#define mvd_pin_dst		info[AUFS_MVDOWN_LOWER].pin
++
++#define AU_MVD_PR(flag, ...) do {			\
++		if (flag)				\
++			pr_err(__VA_ARGS__);		\
++	} while (0)
++
++static int find_lower_writable(struct au_mvd_args *a)
++{
++	struct super_block *sb;
++	aufs_bindex_t bindex, bend;
++	struct au_branch *br;
++
++	sb = a->sb;
++	bindex = a->mvd_bsrc;
++	bend = au_sbend(sb);
++	if (a->mvdown.flags & AUFS_MVDOWN_FHSM_LOWER)
++		for (bindex++; bindex <= bend; bindex++) {
++			br = au_sbr(sb, bindex);
++			if (au_br_fhsm(br->br_perm)
++			    && (!(au_br_sb(br)->s_flags & MS_RDONLY)))
++				return bindex;
++		}
++	else if (!(a->mvdown.flags & AUFS_MVDOWN_ROLOWER))
++		for (bindex++; bindex <= bend; bindex++) {
++			br = au_sbr(sb, bindex);
++			if (!au_br_rdonly(br))
++				return bindex;
++		}
++	else
++		for (bindex++; bindex <= bend; bindex++) {
++			br = au_sbr(sb, bindex);
++			if (!(au_br_sb(br)->s_flags & MS_RDONLY)) {
++				if (au_br_rdonly(br))
++					a->mvdown.flags
++						|= AUFS_MVDOWN_ROLOWER_R;
++				return bindex;
++			}
++		}
++
++	return -1;
++}
++
++/* make the parent dir on bdst */
++static int au_do_mkdir(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++
++	err = 0;
++	a->mvd_hdir_src = au_hi(a->dir, a->mvd_bsrc);
++	a->mvd_hdir_dst = au_hi(a->dir, a->mvd_bdst);
++	a->mvd_h_src_parent = au_h_dptr(a->parent, a->mvd_bsrc);
++	a->mvd_h_dst_parent = NULL;
++	if (au_dbend(a->parent) >= a->mvd_bdst)
++		a->mvd_h_dst_parent = au_h_dptr(a->parent, a->mvd_bdst);
++	if (!a->mvd_h_dst_parent) {
++		err = au_cpdown_dirs(a->dentry, a->mvd_bdst);
++		if (unlikely(err)) {
++			AU_MVD_PR(dmsg, "cpdown_dirs failed\n");
++			goto out;
++		}
++		a->mvd_h_dst_parent = au_h_dptr(a->parent, a->mvd_bdst);
++	}
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* lock them all */
++static int au_do_lock(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++	struct dentry *h_trap;
++
++	a->mvd_h_src_sb = au_sbr_sb(a->sb, a->mvd_bsrc);
++	a->mvd_h_dst_sb = au_sbr_sb(a->sb, a->mvd_bdst);
++	err = au_pin(&a->mvd_pin_dst, a->dentry, a->mvd_bdst,
++		     au_opt_udba(a->sb),
++		     AuPin_MNT_WRITE | AuPin_DI_LOCKED);
++	AuTraceErr(err);
++	if (unlikely(err)) {
++		AU_MVD_PR(dmsg, "pin_dst failed\n");
++		goto out;
++	}
++
++	if (a->mvd_h_src_sb != a->mvd_h_dst_sb) {
++		a->rename_lock = 0;
++		au_pin_init(&a->mvd_pin_src, a->dentry, a->mvd_bsrc,
++			    AuLsc_DI_PARENT, AuLsc_I_PARENT3,
++			    au_opt_udba(a->sb),
++			    AuPin_MNT_WRITE | AuPin_DI_LOCKED);
++		err = au_do_pin(&a->mvd_pin_src);
++		AuTraceErr(err);
++		a->mvd_h_src_dir = a->mvd_h_src_parent->d_inode;
++		if (unlikely(err)) {
++			AU_MVD_PR(dmsg, "pin_src failed\n");
++			goto out_dst;
++		}
++		goto out; /* success */
++	}
++
++	a->rename_lock = 1;
++	au_pin_hdir_unlock(&a->mvd_pin_dst);
++	err = au_pin(&a->mvd_pin_src, a->dentry, a->mvd_bsrc,
++		     au_opt_udba(a->sb),
++		     AuPin_MNT_WRITE | AuPin_DI_LOCKED);
++	AuTraceErr(err);
++	a->mvd_h_src_dir = a->mvd_h_src_parent->d_inode;
++	if (unlikely(err)) {
++		AU_MVD_PR(dmsg, "pin_src failed\n");
++		au_pin_hdir_lock(&a->mvd_pin_dst);
++		goto out_dst;
++	}
++	au_pin_hdir_unlock(&a->mvd_pin_src);
++	h_trap = vfsub_lock_rename(a->mvd_h_src_parent, a->mvd_hdir_src,
++				   a->mvd_h_dst_parent, a->mvd_hdir_dst);
++	if (h_trap) {
++		err = (h_trap != a->mvd_h_src_parent);
++		if (err)
++			err = (h_trap != a->mvd_h_dst_parent);
++	}
++	BUG_ON(err); /* it should never happen */
++	if (unlikely(a->mvd_h_src_dir != au_pinned_h_dir(&a->mvd_pin_src))) {
++		err = -EBUSY;
++		AuTraceErr(err);
++		vfsub_unlock_rename(a->mvd_h_src_parent, a->mvd_hdir_src,
++				    a->mvd_h_dst_parent, a->mvd_hdir_dst);
++		au_pin_hdir_lock(&a->mvd_pin_src);
++		au_unpin(&a->mvd_pin_src);
++		au_pin_hdir_lock(&a->mvd_pin_dst);
++		goto out_dst;
++	}
++	goto out; /* success */
++
++out_dst:
++	au_unpin(&a->mvd_pin_dst);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++static void au_do_unlock(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	if (!a->rename_lock)
++		au_unpin(&a->mvd_pin_src);
++	else {
++		vfsub_unlock_rename(a->mvd_h_src_parent, a->mvd_hdir_src,
++				    a->mvd_h_dst_parent, a->mvd_hdir_dst);
++		au_pin_hdir_lock(&a->mvd_pin_src);
++		au_unpin(&a->mvd_pin_src);
++		au_pin_hdir_lock(&a->mvd_pin_dst);
++	}
++	au_unpin(&a->mvd_pin_dst);
++}
++
++/* copy-down the file */
++static int au_do_cpdown(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++	struct au_cp_generic cpg = {
++		.dentry	= a->dentry,
++		.bdst	= a->mvd_bdst,
++		.bsrc	= a->mvd_bsrc,
++		.len	= -1,
++		.pin	= &a->mvd_pin_dst,
++		.flags	= AuCpup_DTIME | AuCpup_HOPEN
++	};
++
++	AuDbg("b%d, b%d\n", cpg.bsrc, cpg.bdst);
++	if (a->mvdown.flags & AUFS_MVDOWN_OWLOWER)
++		au_fset_cpup(cpg.flags, OVERWRITE);
++	if (a->mvdown.flags & AUFS_MVDOWN_ROLOWER)
++		au_fset_cpup(cpg.flags, RWDST);
++	err = au_sio_cpdown_simple(&cpg);
++	if (unlikely(err))
++		AU_MVD_PR(dmsg, "cpdown failed\n");
++
++	AuTraceErr(err);
++	return err;
++}
++
++/*
++ * unlink the whiteout on bdst if exist which may be created by UDBA while we
++ * were sleeping
++ */
++static int au_do_unlink_wh(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++	struct path h_path;
++	struct au_branch *br;
++	struct inode *delegated;
++
++	br = au_sbr(a->sb, a->mvd_bdst);
++	h_path.dentry = au_wh_lkup(a->mvd_h_dst_parent, &a->dentry->d_name, br);
++	err = PTR_ERR(h_path.dentry);
++	if (IS_ERR(h_path.dentry)) {
++		AU_MVD_PR(dmsg, "wh_lkup failed\n");
++		goto out;
++	}
++
++	err = 0;
++	if (h_path.dentry->d_inode) {
++		h_path.mnt = au_br_mnt(br);
++		delegated = NULL;
++		err = vfsub_unlink(a->mvd_h_dst_parent->d_inode, &h_path,
++				   &delegated, /*force*/0);
++		if (unlikely(err == -EWOULDBLOCK)) {
++			pr_warn("cannot retry for NFSv4 delegation"
++				" for an internal unlink\n");
++			iput(delegated);
++		}
++		if (unlikely(err))
++			AU_MVD_PR(dmsg, "wh_unlink failed\n");
++	}
++	dput(h_path.dentry);
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/*
++ * unlink the topmost h_dentry
++ */
++static int au_do_unlink(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++	struct path h_path;
++	struct inode *delegated;
++
++	h_path.mnt = au_sbr_mnt(a->sb, a->mvd_bsrc);
++	h_path.dentry = au_h_dptr(a->dentry, a->mvd_bsrc);
++	delegated = NULL;
++	err = vfsub_unlink(a->mvd_h_src_dir, &h_path, &delegated, /*force*/0);
++	if (unlikely(err == -EWOULDBLOCK)) {
++		pr_warn("cannot retry for NFSv4 delegation"
++			" for an internal unlink\n");
++		iput(delegated);
++	}
++	if (unlikely(err))
++		AU_MVD_PR(dmsg, "unlink failed\n");
++
++	AuTraceErr(err);
++	return err;
++}
++
++/* Since mvdown succeeded, we ignore an error of this function */
++static void au_do_stfs(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++	struct au_branch *br;
++
++	a->mvdown.flags |= AUFS_MVDOWN_STFS_FAILED;
++	br = au_sbr(a->sb, a->mvd_bsrc);
++	err = au_br_stfs(br, &a->mvdown.stbr[AUFS_MVDOWN_UPPER].stfs);
++	if (!err) {
++		br = au_sbr(a->sb, a->mvd_bdst);
++		a->mvdown.stbr[AUFS_MVDOWN_LOWER].brid = br->br_id;
++		err = au_br_stfs(br, &a->mvdown.stbr[AUFS_MVDOWN_LOWER].stfs);
++	}
++	if (!err)
++		a->mvdown.flags &= ~AUFS_MVDOWN_STFS_FAILED;
++	else
++		AU_MVD_PR(dmsg, "statfs failed (%d), ignored\n", err);
++}
++
++/*
++ * copy-down the file and unlink the bsrc file.
++ * - unlink the bdst whout if exist
++ * - copy-down the file (with whtmp name and rename)
++ * - unlink the bsrc file
++ */
++static int au_do_mvdown(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++
++	err = au_do_mkdir(dmsg, a);
++	if (!err)
++		err = au_do_lock(dmsg, a);
++	if (unlikely(err))
++		goto out;
++
++	/*
++	 * do not revert the activities we made on bdst since they should be
++	 * harmless in aufs.
++	 */
++
++	err = au_do_cpdown(dmsg, a);
++	if (!err)
++		err = au_do_unlink_wh(dmsg, a);
++	if (!err && !(a->mvdown.flags & AUFS_MVDOWN_KUPPER))
++		err = au_do_unlink(dmsg, a);
++	if (unlikely(err))
++		goto out_unlock;
++
++	AuDbg("%pd2, 0x%x, %d --> %d\n",
++	      a->dentry, a->mvdown.flags, a->mvd_bsrc, a->mvd_bdst);
++	if (find_lower_writable(a) < 0)
++		a->mvdown.flags |= AUFS_MVDOWN_BOTTOM;
++
++	if (a->mvdown.flags & AUFS_MVDOWN_STFS)
++		au_do_stfs(dmsg, a);
++
++	/* maintain internal array */
++	if (!(a->mvdown.flags & AUFS_MVDOWN_KUPPER)) {
++		au_set_h_dptr(a->dentry, a->mvd_bsrc, NULL);
++		au_set_dbstart(a->dentry, a->mvd_bdst);
++		au_set_h_iptr(a->inode, a->mvd_bsrc, NULL, /*flags*/0);
++		au_set_ibstart(a->inode, a->mvd_bdst);
++	}
++	if (au_dbend(a->dentry) < a->mvd_bdst)
++		au_set_dbend(a->dentry, a->mvd_bdst);
++	if (au_ibend(a->inode) < a->mvd_bdst)
++		au_set_ibend(a->inode, a->mvd_bdst);
++
++out_unlock:
++	au_do_unlock(dmsg, a);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* make sure the file is idle */
++static int au_mvd_args_busy(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err, plinked;
++
++	err = 0;
++	plinked = !!au_opt_test(au_mntflags(a->sb), PLINK);
++	if (au_dbstart(a->dentry) == a->mvd_bsrc
++	    && au_dcount(a->dentry) == 1
++	    && atomic_read(&a->inode->i_count) == 1
++	    /* && a->mvd_h_src_inode->i_nlink == 1 */
++	    && (!plinked || !au_plink_test(a->inode))
++	    && a->inode->i_nlink == 1)
++		goto out;
++
++	err = -EBUSY;
++	AU_MVD_PR(dmsg,
++		  "b%d, d{b%d, c%d?}, i{c%d?, l%u}, hi{l%u}, p{%d, %d}\n",
++		  a->mvd_bsrc, au_dbstart(a->dentry), au_dcount(a->dentry),
++		  atomic_read(&a->inode->i_count), a->inode->i_nlink,
++		  a->mvd_h_src_inode->i_nlink,
++		  plinked, plinked ? au_plink_test(a->inode) : 0);
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* make sure the parent dir is fine */
++static int au_mvd_args_parent(const unsigned char dmsg,
++			      struct au_mvd_args *a)
++{
++	int err;
++	aufs_bindex_t bindex;
++
++	err = 0;
++	if (unlikely(au_alive_dir(a->parent))) {
++		err = -ENOENT;
++		AU_MVD_PR(dmsg, "parent dir is dead\n");
++		goto out;
++	}
++
++	a->bopq = au_dbdiropq(a->parent);
++	bindex = au_wbr_nonopq(a->dentry, a->mvd_bdst);
++	AuDbg("b%d\n", bindex);
++	if (unlikely((bindex >= 0 && bindex < a->mvd_bdst)
++		     || (a->bopq != -1 && a->bopq < a->mvd_bdst))) {
++		err = -EINVAL;
++		a->mvd_errno = EAU_MVDOWN_OPAQUE;
++		AU_MVD_PR(dmsg, "ancestor is opaque b%d, b%d\n",
++			  a->bopq, a->mvd_bdst);
++	}
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int au_mvd_args_intermediate(const unsigned char dmsg,
++				    struct au_mvd_args *a)
++{
++	int err;
++	struct au_dinfo *dinfo, *tmp;
++
++	/* lookup the next lower positive entry */
++	err = -ENOMEM;
++	tmp = au_di_alloc(a->sb, AuLsc_DI_TMP);
++	if (unlikely(!tmp))
++		goto out;
++
++	a->bfound = -1;
++	a->bwh = -1;
++	dinfo = au_di(a->dentry);
++	au_di_cp(tmp, dinfo);
++	au_di_swap(tmp, dinfo);
++
++	/* returns the number of positive dentries */
++	err = au_lkup_dentry(a->dentry, a->mvd_bsrc + 1, /*type*/0);
++	if (!err)
++		a->bwh = au_dbwh(a->dentry);
++	else if (err > 0)
++		a->bfound = au_dbstart(a->dentry);
++
++	au_di_swap(tmp, dinfo);
++	au_rw_write_unlock(&tmp->di_rwsem);
++	au_di_free(tmp);
++	if (unlikely(err < 0))
++		AU_MVD_PR(dmsg, "failed look-up lower\n");
++
++	/*
++	 * here, we have these cases.
++	 * bfound == -1
++	 *	no positive dentry under bsrc. there are more sub-cases.
++	 *	bwh < 0
++	 *		there no whiteout, we can safely move-down.
++	 *	bwh <= bsrc
++	 *		impossible
++	 *	bsrc < bwh && bwh < bdst
++	 *		there is a whiteout on RO branch. cannot proceed.
++	 *	bwh == bdst
++	 *		there is a whiteout on the RW target branch. it should
++	 *		be removed.
++	 *	bdst < bwh
++	 *		there is a whiteout somewhere unrelated branch.
++	 * -1 < bfound && bfound <= bsrc
++	 *	impossible.
++	 * bfound < bdst
++	 *	found, but it is on RO branch between bsrc and bdst. cannot
++	 *	proceed.
++	 * bfound == bdst
++	 *	found, replace it if AUFS_MVDOWN_FORCE is set. otherwise return
++	 *	error.
++	 * bdst < bfound
++	 *	found, after we create the file on bdst, it will be hidden.
++	 */
++
++	AuDebugOn(a->bfound == -1
++		  && a->bwh != -1
++		  && a->bwh <= a->mvd_bsrc);
++	AuDebugOn(-1 < a->bfound
++		  && a->bfound <= a->mvd_bsrc);
++
++	err = -EINVAL;
++	if (a->bfound == -1
++	    && a->mvd_bsrc < a->bwh
++	    && a->bwh != -1
++	    && a->bwh < a->mvd_bdst) {
++		a->mvd_errno = EAU_MVDOWN_WHITEOUT;
++		AU_MVD_PR(dmsg, "bsrc %d, bdst %d, bfound %d, bwh %d\n",
++			  a->mvd_bsrc, a->mvd_bdst, a->bfound, a->bwh);
++		goto out;
++	} else if (a->bfound != -1 && a->bfound < a->mvd_bdst) {
++		a->mvd_errno = EAU_MVDOWN_UPPER;
++		AU_MVD_PR(dmsg, "bdst %d, bfound %d\n",
++			  a->mvd_bdst, a->bfound);
++		goto out;
++	}
++
++	err = 0; /* success */
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int au_mvd_args_exist(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++
++	err = 0;
++	if (!(a->mvdown.flags & AUFS_MVDOWN_OWLOWER)
++	    && a->bfound == a->mvd_bdst)
++		err = -EEXIST;
++	AuTraceErr(err);
++	return err;
++}
++
++static int au_mvd_args(const unsigned char dmsg, struct au_mvd_args *a)
++{
++	int err;
++	struct au_branch *br;
++
++	err = -EISDIR;
++	if (unlikely(S_ISDIR(a->inode->i_mode)))
++		goto out;
++
++	err = -EINVAL;
++	if (!(a->mvdown.flags & AUFS_MVDOWN_BRID_UPPER))
++		a->mvd_bsrc = au_ibstart(a->inode);
++	else {
++		a->mvd_bsrc = au_br_index(a->sb, a->mvd_src_brid);
++		if (unlikely(a->mvd_bsrc < 0
++			     || (a->mvd_bsrc < au_dbstart(a->dentry)
++				 || au_dbend(a->dentry) < a->mvd_bsrc
++				 || !au_h_dptr(a->dentry, a->mvd_bsrc))
++			     || (a->mvd_bsrc < au_ibstart(a->inode)
++				 || au_ibend(a->inode) < a->mvd_bsrc
++				 || !au_h_iptr(a->inode, a->mvd_bsrc)))) {
++			a->mvd_errno = EAU_MVDOWN_NOUPPER;
++			AU_MVD_PR(dmsg, "no upper\n");
++			goto out;
++		}
++	}
++	if (unlikely(a->mvd_bsrc == au_sbend(a->sb))) {
++		a->mvd_errno = EAU_MVDOWN_BOTTOM;
++		AU_MVD_PR(dmsg, "on the bottom\n");
++		goto out;
++	}
++	a->mvd_h_src_inode = au_h_iptr(a->inode, a->mvd_bsrc);
++	br = au_sbr(a->sb, a->mvd_bsrc);
++	err = au_br_rdonly(br);
++	if (!(a->mvdown.flags & AUFS_MVDOWN_ROUPPER)) {
++		if (unlikely(err))
++			goto out;
++	} else if (!(vfsub_native_ro(a->mvd_h_src_inode)
++		     || IS_APPEND(a->mvd_h_src_inode))) {
++		if (err)
++			a->mvdown.flags |= AUFS_MVDOWN_ROUPPER_R;
++		/* go on */
++	} else
++		goto out;
++
++	err = -EINVAL;
++	if (!(a->mvdown.flags & AUFS_MVDOWN_BRID_LOWER)) {
++		a->mvd_bdst = find_lower_writable(a);
++		if (unlikely(a->mvd_bdst < 0)) {
++			a->mvd_errno = EAU_MVDOWN_BOTTOM;
++			AU_MVD_PR(dmsg, "no writable lower branch\n");
++			goto out;
++		}
++	} else {
++		a->mvd_bdst = au_br_index(a->sb, a->mvd_dst_brid);
++		if (unlikely(a->mvd_bdst < 0
++			     || au_sbend(a->sb) < a->mvd_bdst)) {
++			a->mvd_errno = EAU_MVDOWN_NOLOWERBR;
++			AU_MVD_PR(dmsg, "no lower brid\n");
++			goto out;
++		}
++	}
++
++	err = au_mvd_args_busy(dmsg, a);
++	if (!err)
++		err = au_mvd_args_parent(dmsg, a);
++	if (!err)
++		err = au_mvd_args_intermediate(dmsg, a);
++	if (!err)
++		err = au_mvd_args_exist(dmsg, a);
++	if (!err)
++		AuDbg("b%d, b%d\n", a->mvd_bsrc, a->mvd_bdst);
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++int au_mvdown(struct dentry *dentry, struct aufs_mvdown __user *uarg)
++{
++	int err, e;
++	unsigned char dmsg;
++	struct au_mvd_args *args;
++
++	err = -EPERM;
++	if (unlikely(!capable(CAP_SYS_ADMIN)))
++		goto out;
++
++	err = -ENOMEM;
++	args = kmalloc(sizeof(*args), GFP_NOFS);
++	if (unlikely(!args))
++		goto out;
++
++	err = copy_from_user(&args->mvdown, uarg, sizeof(args->mvdown));
++	if (!err)
++		err = !access_ok(VERIFY_WRITE, uarg, sizeof(*uarg));
++	if (unlikely(err)) {
++		err = -EFAULT;
++		AuTraceErr(err);
++		goto out_free;
++	}
++	AuDbg("flags 0x%x\n", args->mvdown.flags);
++	args->mvdown.flags &= ~(AUFS_MVDOWN_ROLOWER_R | AUFS_MVDOWN_ROUPPER_R);
++	args->mvdown.au_errno = 0;
++	args->dentry = dentry;
++	args->inode = dentry->d_inode;
++	args->sb = dentry->d_sb;
++
++	err = -ENOENT;
++	dmsg = !!(args->mvdown.flags & AUFS_MVDOWN_DMSG);
++	args->parent = dget_parent(dentry);
++	args->dir = args->parent->d_inode;
++	mutex_lock_nested(&args->dir->i_mutex, I_MUTEX_PARENT);
++	dput(args->parent);
++	if (unlikely(args->parent != dentry->d_parent)) {
++		AU_MVD_PR(dmsg, "parent dir is moved\n");
++		goto out_dir;
++	}
++
++	mutex_lock_nested(&args->inode->i_mutex, I_MUTEX_CHILD);
++	err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH);
++	if (unlikely(err))
++		goto out_inode;
++
++	di_write_lock_parent(args->parent);
++	err = au_mvd_args(dmsg, args);
++	if (unlikely(err))
++		goto out_parent;
++
++	err = au_do_mvdown(dmsg, args);
++	if (unlikely(err))
++		goto out_parent;
++
++	au_cpup_attr_timesizes(args->dir);
++	au_cpup_attr_timesizes(args->inode);
++	au_cpup_igen(args->inode, au_h_iptr(args->inode, args->mvd_bdst));
++	/* au_digen_dec(dentry); */
++
++out_parent:
++	di_write_unlock(args->parent);
++	aufs_read_unlock(dentry, AuLock_DW);
++out_inode:
++	mutex_unlock(&args->inode->i_mutex);
++out_dir:
++	mutex_unlock(&args->dir->i_mutex);
++out_free:
++	e = copy_to_user(uarg, &args->mvdown, sizeof(args->mvdown));
++	if (unlikely(e))
++		err = -EFAULT;
++	kfree(args);
++out:
++	AuTraceErr(err);
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/opts.c linux-4.0.4/fs/aufs/opts.c
+--- linux-4.0.4.orig/fs/aufs/opts.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/opts.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,1822 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * mount options/flags
++ */
++
++#include <linux/namei.h>
++#include <linux/types.h> /* a distribution requires */
++#include <linux/parser.h>
++#include "aufs.h"
++
++/* ---------------------------------------------------------------------- */
++
++enum {
++	Opt_br,
++	Opt_add, Opt_del, Opt_mod, Opt_append, Opt_prepend,
++	Opt_idel, Opt_imod,
++	Opt_dirwh, Opt_rdcache, Opt_rdblk, Opt_rdhash,
++	Opt_rdblk_def, Opt_rdhash_def,
++	Opt_xino, Opt_noxino,
++	Opt_trunc_xino, Opt_trunc_xino_v, Opt_notrunc_xino,
++	Opt_trunc_xino_path, Opt_itrunc_xino,
++	Opt_trunc_xib, Opt_notrunc_xib,
++	Opt_shwh, Opt_noshwh,
++	Opt_plink, Opt_noplink, Opt_list_plink,
++	Opt_udba,
++	Opt_dio, Opt_nodio,
++	Opt_diropq_a, Opt_diropq_w,
++	Opt_warn_perm, Opt_nowarn_perm,
++	Opt_wbr_copyup, Opt_wbr_create,
++	Opt_fhsm_sec,
++	Opt_verbose, Opt_noverbose,
++	Opt_sum, Opt_nosum, Opt_wsum,
++	Opt_dirperm1, Opt_nodirperm1,
++	Opt_acl, Opt_noacl,
++	Opt_tail, Opt_ignore, Opt_ignore_silent, Opt_err
++};
++
++static match_table_t options = {
++	{Opt_br, "br=%s"},
++	{Opt_br, "br:%s"},
++
++	{Opt_add, "add=%d:%s"},
++	{Opt_add, "add:%d:%s"},
++	{Opt_add, "ins=%d:%s"},
++	{Opt_add, "ins:%d:%s"},
++	{Opt_append, "append=%s"},
++	{Opt_append, "append:%s"},
++	{Opt_prepend, "prepend=%s"},
++	{Opt_prepend, "prepend:%s"},
++
++	{Opt_del, "del=%s"},
++	{Opt_del, "del:%s"},
++	/* {Opt_idel, "idel:%d"}, */
++	{Opt_mod, "mod=%s"},
++	{Opt_mod, "mod:%s"},
++	/* {Opt_imod, "imod:%d:%s"}, */
++
++	{Opt_dirwh, "dirwh=%d"},
++
++	{Opt_xino, "xino=%s"},
++	{Opt_noxino, "noxino"},
++	{Opt_trunc_xino, "trunc_xino"},
++	{Opt_trunc_xino_v, "trunc_xino_v=%d:%d"},
++	{Opt_notrunc_xino, "notrunc_xino"},
++	{Opt_trunc_xino_path, "trunc_xino=%s"},
++	{Opt_itrunc_xino, "itrunc_xino=%d"},
++	/* {Opt_zxino, "zxino=%s"}, */
++	{Opt_trunc_xib, "trunc_xib"},
++	{Opt_notrunc_xib, "notrunc_xib"},
++
++#ifdef CONFIG_PROC_FS
++	{Opt_plink, "plink"},
++#else
++	{Opt_ignore_silent, "plink"},
++#endif
++
++	{Opt_noplink, "noplink"},
++
++#ifdef CONFIG_AUFS_DEBUG
++	{Opt_list_plink, "list_plink"},
++#endif
++
++	{Opt_udba, "udba=%s"},
++
++	{Opt_dio, "dio"},
++	{Opt_nodio, "nodio"},
++
++#ifdef CONFIG_AUFS_FHSM
++	{Opt_fhsm_sec, "fhsm_sec=%d"},
++#else
++	{Opt_ignore_silent, "fhsm_sec=%d"},
++#endif
++
++	{Opt_diropq_a, "diropq=always"},
++	{Opt_diropq_a, "diropq=a"},
++	{Opt_diropq_w, "diropq=whiteouted"},
++	{Opt_diropq_w, "diropq=w"},
++
++	{Opt_warn_perm, "warn_perm"},
++	{Opt_nowarn_perm, "nowarn_perm"},
++
++	/* keep them temporary */
++	{Opt_ignore_silent, "nodlgt"},
++	{Opt_ignore_silent, "clean_plink"},
++
++#ifdef CONFIG_AUFS_SHWH
++	{Opt_shwh, "shwh"},
++#endif
++	{Opt_noshwh, "noshwh"},
++
++	{Opt_dirperm1, "dirperm1"},
++	{Opt_nodirperm1, "nodirperm1"},
++
++	{Opt_verbose, "verbose"},
++	{Opt_verbose, "v"},
++	{Opt_noverbose, "noverbose"},
++	{Opt_noverbose, "quiet"},
++	{Opt_noverbose, "q"},
++	{Opt_noverbose, "silent"},
++
++	{Opt_sum, "sum"},
++	{Opt_nosum, "nosum"},
++	{Opt_wsum, "wsum"},
++
++	{Opt_rdcache, "rdcache=%d"},
++	{Opt_rdblk, "rdblk=%d"},
++	{Opt_rdblk_def, "rdblk=def"},
++	{Opt_rdhash, "rdhash=%d"},
++	{Opt_rdhash_def, "rdhash=def"},
++
++	{Opt_wbr_create, "create=%s"},
++	{Opt_wbr_create, "create_policy=%s"},
++	{Opt_wbr_copyup, "cpup=%s"},
++	{Opt_wbr_copyup, "copyup=%s"},
++	{Opt_wbr_copyup, "copyup_policy=%s"},
++
++	/* generic VFS flag */
++#ifdef CONFIG_FS_POSIX_ACL
++	{Opt_acl, "acl"},
++	{Opt_noacl, "noacl"},
++#else
++	{Opt_ignore_silent, "acl"},
++	{Opt_ignore_silent, "noacl"},
++#endif
++
++	/* internal use for the scripts */
++	{Opt_ignore_silent, "si=%s"},
++
++	{Opt_br, "dirs=%s"},
++	{Opt_ignore, "debug=%d"},
++	{Opt_ignore, "delete=whiteout"},
++	{Opt_ignore, "delete=all"},
++	{Opt_ignore, "imap=%s"},
++
++	/* temporary workaround, due to old mount(8)? */
++	{Opt_ignore_silent, "relatime"},
++
++	{Opt_err, NULL}
++};
++
++/* ---------------------------------------------------------------------- */
++
++static const char *au_parser_pattern(int val, match_table_t tbl)
++{
++	struct match_token *p;
++
++	p = tbl;
++	while (p->pattern) {
++		if (p->token == val)
++			return p->pattern;
++		p++;
++	}
++	BUG();
++	return "??";
++}
++
++static const char *au_optstr(int *val, match_table_t tbl)
++{
++	struct match_token *p;
++	int v;
++
++	v = *val;
++	if (!v)
++		goto out;
++	p = tbl;
++	while (p->pattern) {
++		if (p->token
++		    && (v & p->token) == p->token) {
++			*val &= ~p->token;
++			return p->pattern;
++		}
++		p++;
++	}
++
++out:
++	return NULL;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static match_table_t brperm = {
++	{AuBrPerm_RO, AUFS_BRPERM_RO},
++	{AuBrPerm_RR, AUFS_BRPERM_RR},
++	{AuBrPerm_RW, AUFS_BRPERM_RW},
++	{0, NULL}
++};
++
++static match_table_t brattr = {
++	/* general */
++	{AuBrAttr_COO_REG, AUFS_BRATTR_COO_REG},
++	{AuBrAttr_COO_ALL, AUFS_BRATTR_COO_ALL},
++	/* 'unpin' attrib is meaningless since linux-3.18-rc1 */
++	{AuBrAttr_UNPIN, AUFS_BRATTR_UNPIN},
++#ifdef CONFIG_AUFS_FHSM
++	{AuBrAttr_FHSM, AUFS_BRATTR_FHSM},
++#endif
++#ifdef CONFIG_AUFS_XATTR
++	{AuBrAttr_ICEX, AUFS_BRATTR_ICEX},
++	{AuBrAttr_ICEX_SEC, AUFS_BRATTR_ICEX_SEC},
++	{AuBrAttr_ICEX_SYS, AUFS_BRATTR_ICEX_SYS},
++	{AuBrAttr_ICEX_TR, AUFS_BRATTR_ICEX_TR},
++	{AuBrAttr_ICEX_USR, AUFS_BRATTR_ICEX_USR},
++	{AuBrAttr_ICEX_OTH, AUFS_BRATTR_ICEX_OTH},
++#endif
++
++	/* ro/rr branch */
++	{AuBrRAttr_WH, AUFS_BRRATTR_WH},
++
++	/* rw branch */
++	{AuBrWAttr_MOO, AUFS_BRWATTR_MOO},
++	{AuBrWAttr_NoLinkWH, AUFS_BRWATTR_NLWH},
++
++	{0, NULL}
++};
++
++static int br_attr_val(char *str, match_table_t table, substring_t args[])
++{
++	int attr, v;
++	char *p;
++
++	attr = 0;
++	do {
++		p = strchr(str, '+');
++		if (p)
++			*p = 0;
++		v = match_token(str, table, args);
++		if (v) {
++			if (v & AuBrAttr_CMOO_Mask)
++				attr &= ~AuBrAttr_CMOO_Mask;
++			attr |= v;
++		} else {
++			if (p)
++				*p = '+';
++			pr_warn("ignored branch attribute %s\n", str);
++			break;
++		}
++		if (p)
++			str = p + 1;
++	} while (p);
++
++	return attr;
++}
++
++static int au_do_optstr_br_attr(au_br_perm_str_t *str, int perm)
++{
++	int sz;
++	const char *p;
++	char *q;
++
++	q = str->a;
++	*q = 0;
++	p = au_optstr(&perm, brattr);
++	if (p) {
++		sz = strlen(p);
++		memcpy(q, p, sz + 1);
++		q += sz;
++	} else
++		goto out;
++
++	do {
++		p = au_optstr(&perm, brattr);
++		if (p) {
++			*q++ = '+';
++			sz = strlen(p);
++			memcpy(q, p, sz + 1);
++			q += sz;
++		}
++	} while (p);
++
++out:
++	return q - str->a;
++}
++
++static int noinline_for_stack br_perm_val(char *perm)
++{
++	int val, bad, sz;
++	char *p;
++	substring_t args[MAX_OPT_ARGS];
++	au_br_perm_str_t attr;
++
++	p = strchr(perm, '+');
++	if (p)
++		*p = 0;
++	val = match_token(perm, brperm, args);
++	if (!val) {
++		if (p)
++			*p = '+';
++		pr_warn("ignored branch permission %s\n", perm);
++		val = AuBrPerm_RO;
++		goto out;
++	}
++	if (!p)
++		goto out;
++
++	val |= br_attr_val(p + 1, brattr, args);
++
++	bad = 0;
++	switch (val & AuBrPerm_Mask) {
++	case AuBrPerm_RO:
++	case AuBrPerm_RR:
++		bad = val & AuBrWAttr_Mask;
++		val &= ~AuBrWAttr_Mask;
++		break;
++	case AuBrPerm_RW:
++		bad = val & AuBrRAttr_Mask;
++		val &= ~AuBrRAttr_Mask;
++		break;
++	}
++
++	/*
++	 * 'unpin' attrib becomes meaningless since linux-3.18-rc1, but aufs
++	 * does not treat it as an error, just warning.
++	 * this is a tiny guard for the user operation.
++	 */
++	if (val & AuBrAttr_UNPIN) {
++		bad |= AuBrAttr_UNPIN;
++		val &= ~AuBrAttr_UNPIN;
++	}
++
++	if (unlikely(bad)) {
++		sz = au_do_optstr_br_attr(&attr, bad);
++		AuDebugOn(!sz);
++		pr_warn("ignored branch attribute %s\n", attr.a);
++	}
++
++out:
++	return val;
++}
++
++void au_optstr_br_perm(au_br_perm_str_t *str, int perm)
++{
++	au_br_perm_str_t attr;
++	const char *p;
++	char *q;
++	int sz;
++
++	q = str->a;
++	p = au_optstr(&perm, brperm);
++	AuDebugOn(!p || !*p);
++	sz = strlen(p);
++	memcpy(q, p, sz + 1);
++	q += sz;
++
++	sz = au_do_optstr_br_attr(&attr, perm);
++	if (sz) {
++		*q++ = '+';
++		memcpy(q, attr.a, sz + 1);
++	}
++
++	AuDebugOn(strlen(str->a) >= sizeof(str->a));
++}
++
++/* ---------------------------------------------------------------------- */
++
++static match_table_t udbalevel = {
++	{AuOpt_UDBA_REVAL, "reval"},
++	{AuOpt_UDBA_NONE, "none"},
++#ifdef CONFIG_AUFS_HNOTIFY
++	{AuOpt_UDBA_HNOTIFY, "notify"}, /* abstraction */
++#ifdef CONFIG_AUFS_HFSNOTIFY
++	{AuOpt_UDBA_HNOTIFY, "fsnotify"},
++#endif
++#endif
++	{-1, NULL}
++};
++
++static int noinline_for_stack udba_val(char *str)
++{
++	substring_t args[MAX_OPT_ARGS];
++
++	return match_token(str, udbalevel, args);
++}
++
++const char *au_optstr_udba(int udba)
++{
++	return au_parser_pattern(udba, udbalevel);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static match_table_t au_wbr_create_policy = {
++	{AuWbrCreate_TDP, "tdp"},
++	{AuWbrCreate_TDP, "top-down-parent"},
++	{AuWbrCreate_RR, "rr"},
++	{AuWbrCreate_RR, "round-robin"},
++	{AuWbrCreate_MFS, "mfs"},
++	{AuWbrCreate_MFS, "most-free-space"},
++	{AuWbrCreate_MFSV, "mfs:%d"},
++	{AuWbrCreate_MFSV, "most-free-space:%d"},
++
++	{AuWbrCreate_MFSRR, "mfsrr:%d"},
++	{AuWbrCreate_MFSRRV, "mfsrr:%d:%d"},
++	{AuWbrCreate_PMFS, "pmfs"},
++	{AuWbrCreate_PMFSV, "pmfs:%d"},
++	{AuWbrCreate_PMFSRR, "pmfsrr:%d"},
++	{AuWbrCreate_PMFSRRV, "pmfsrr:%d:%d"},
++
++	{-1, NULL}
++};
++
++/*
++ * cf. linux/lib/parser.c and cmdline.c
++ * gave up calling memparse() since it uses simple_strtoull() instead of
++ * kstrto...().
++ */
++static int noinline_for_stack
++au_match_ull(substring_t *s, unsigned long long *result)
++{
++	int err;
++	unsigned int len;
++	char a[32];
++
++	err = -ERANGE;
++	len = s->to - s->from;
++	if (len + 1 <= sizeof(a)) {
++		memcpy(a, s->from, len);
++		a[len] = '\0';
++		err = kstrtoull(a, 0, result);
++	}
++	return err;
++}
++
++static int au_wbr_mfs_wmark(substring_t *arg, char *str,
++			    struct au_opt_wbr_create *create)
++{
++	int err;
++	unsigned long long ull;
++
++	err = 0;
++	if (!au_match_ull(arg, &ull))
++		create->mfsrr_watermark = ull;
++	else {
++		pr_err("bad integer in %s\n", str);
++		err = -EINVAL;
++	}
++
++	return err;
++}
++
++static int au_wbr_mfs_sec(substring_t *arg, char *str,
++			  struct au_opt_wbr_create *create)
++{
++	int n, err;
++
++	err = 0;
++	if (!match_int(arg, &n) && 0 <= n && n <= AUFS_MFS_MAX_SEC)
++		create->mfs_second = n;
++	else {
++		pr_err("bad integer in %s\n", str);
++		err = -EINVAL;
++	}
++
++	return err;
++}
++
++static int noinline_for_stack
++au_wbr_create_val(char *str, struct au_opt_wbr_create *create)
++{
++	int err, e;
++	substring_t args[MAX_OPT_ARGS];
++
++	err = match_token(str, au_wbr_create_policy, args);
++	create->wbr_create = err;
++	switch (err) {
++	case AuWbrCreate_MFSRRV:
++	case AuWbrCreate_PMFSRRV:
++		e = au_wbr_mfs_wmark(&args[0], str, create);
++		if (!e)
++			e = au_wbr_mfs_sec(&args[1], str, create);
++		if (unlikely(e))
++			err = e;
++		break;
++	case AuWbrCreate_MFSRR:
++	case AuWbrCreate_PMFSRR:
++		e = au_wbr_mfs_wmark(&args[0], str, create);
++		if (unlikely(e)) {
++			err = e;
++			break;
++		}
++		/*FALLTHROUGH*/
++	case AuWbrCreate_MFS:
++	case AuWbrCreate_PMFS:
++		create->mfs_second = AUFS_MFS_DEF_SEC;
++		break;
++	case AuWbrCreate_MFSV:
++	case AuWbrCreate_PMFSV:
++		e = au_wbr_mfs_sec(&args[0], str, create);
++		if (unlikely(e))
++			err = e;
++		break;
++	}
++
++	return err;
++}
++
++const char *au_optstr_wbr_create(int wbr_create)
++{
++	return au_parser_pattern(wbr_create, au_wbr_create_policy);
++}
++
++static match_table_t au_wbr_copyup_policy = {
++	{AuWbrCopyup_TDP, "tdp"},
++	{AuWbrCopyup_TDP, "top-down-parent"},
++	{AuWbrCopyup_BUP, "bup"},
++	{AuWbrCopyup_BUP, "bottom-up-parent"},
++	{AuWbrCopyup_BU, "bu"},
++	{AuWbrCopyup_BU, "bottom-up"},
++	{-1, NULL}
++};
++
++static int noinline_for_stack au_wbr_copyup_val(char *str)
++{
++	substring_t args[MAX_OPT_ARGS];
++
++	return match_token(str, au_wbr_copyup_policy, args);
++}
++
++const char *au_optstr_wbr_copyup(int wbr_copyup)
++{
++	return au_parser_pattern(wbr_copyup, au_wbr_copyup_policy);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static const int lkup_dirflags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
++
++static void dump_opts(struct au_opts *opts)
++{
++#ifdef CONFIG_AUFS_DEBUG
++	/* reduce stack space */
++	union {
++		struct au_opt_add *add;
++		struct au_opt_del *del;
++		struct au_opt_mod *mod;
++		struct au_opt_xino *xino;
++		struct au_opt_xino_itrunc *xino_itrunc;
++		struct au_opt_wbr_create *create;
++	} u;
++	struct au_opt *opt;
++
++	opt = opts->opt;
++	while (opt->type != Opt_tail) {
++		switch (opt->type) {
++		case Opt_add:
++			u.add = &opt->add;
++			AuDbg("add {b%d, %s, 0x%x, %p}\n",
++				  u.add->bindex, u.add->pathname, u.add->perm,
++				  u.add->path.dentry);
++			break;
++		case Opt_del:
++		case Opt_idel:
++			u.del = &opt->del;
++			AuDbg("del {%s, %p}\n",
++			      u.del->pathname, u.del->h_path.dentry);
++			break;
++		case Opt_mod:
++		case Opt_imod:
++			u.mod = &opt->mod;
++			AuDbg("mod {%s, 0x%x, %p}\n",
++				  u.mod->path, u.mod->perm, u.mod->h_root);
++			break;
++		case Opt_append:
++			u.add = &opt->add;
++			AuDbg("append {b%d, %s, 0x%x, %p}\n",
++				  u.add->bindex, u.add->pathname, u.add->perm,
++				  u.add->path.dentry);
++			break;
++		case Opt_prepend:
++			u.add = &opt->add;
++			AuDbg("prepend {b%d, %s, 0x%x, %p}\n",
++				  u.add->bindex, u.add->pathname, u.add->perm,
++				  u.add->path.dentry);
++			break;
++		case Opt_dirwh:
++			AuDbg("dirwh %d\n", opt->dirwh);
++			break;
++		case Opt_rdcache:
++			AuDbg("rdcache %d\n", opt->rdcache);
++			break;
++		case Opt_rdblk:
++			AuDbg("rdblk %u\n", opt->rdblk);
++			break;
++		case Opt_rdblk_def:
++			AuDbg("rdblk_def\n");
++			break;
++		case Opt_rdhash:
++			AuDbg("rdhash %u\n", opt->rdhash);
++			break;
++		case Opt_rdhash_def:
++			AuDbg("rdhash_def\n");
++			break;
++		case Opt_xino:
++			u.xino = &opt->xino;
++			AuDbg("xino {%s %pD}\n", u.xino->path, u.xino->file);
++			break;
++		case Opt_trunc_xino:
++			AuLabel(trunc_xino);
++			break;
++		case Opt_notrunc_xino:
++			AuLabel(notrunc_xino);
++			break;
++		case Opt_trunc_xino_path:
++		case Opt_itrunc_xino:
++			u.xino_itrunc = &opt->xino_itrunc;
++			AuDbg("trunc_xino %d\n", u.xino_itrunc->bindex);
++			break;
++		case Opt_noxino:
++			AuLabel(noxino);
++			break;
++		case Opt_trunc_xib:
++			AuLabel(trunc_xib);
++			break;
++		case Opt_notrunc_xib:
++			AuLabel(notrunc_xib);
++			break;
++		case Opt_shwh:
++			AuLabel(shwh);
++			break;
++		case Opt_noshwh:
++			AuLabel(noshwh);
++			break;
++		case Opt_dirperm1:
++			AuLabel(dirperm1);
++			break;
++		case Opt_nodirperm1:
++			AuLabel(nodirperm1);
++			break;
++		case Opt_plink:
++			AuLabel(plink);
++			break;
++		case Opt_noplink:
++			AuLabel(noplink);
++			break;
++		case Opt_list_plink:
++			AuLabel(list_plink);
++			break;
++		case Opt_udba:
++			AuDbg("udba %d, %s\n",
++				  opt->udba, au_optstr_udba(opt->udba));
++			break;
++		case Opt_dio:
++			AuLabel(dio);
++			break;
++		case Opt_nodio:
++			AuLabel(nodio);
++			break;
++		case Opt_diropq_a:
++			AuLabel(diropq_a);
++			break;
++		case Opt_diropq_w:
++			AuLabel(diropq_w);
++			break;
++		case Opt_warn_perm:
++			AuLabel(warn_perm);
++			break;
++		case Opt_nowarn_perm:
++			AuLabel(nowarn_perm);
++			break;
++		case Opt_verbose:
++			AuLabel(verbose);
++			break;
++		case Opt_noverbose:
++			AuLabel(noverbose);
++			break;
++		case Opt_sum:
++			AuLabel(sum);
++			break;
++		case Opt_nosum:
++			AuLabel(nosum);
++			break;
++		case Opt_wsum:
++			AuLabel(wsum);
++			break;
++		case Opt_wbr_create:
++			u.create = &opt->wbr_create;
++			AuDbg("create %d, %s\n", u.create->wbr_create,
++				  au_optstr_wbr_create(u.create->wbr_create));
++			switch (u.create->wbr_create) {
++			case AuWbrCreate_MFSV:
++			case AuWbrCreate_PMFSV:
++				AuDbg("%d sec\n", u.create->mfs_second);
++				break;
++			case AuWbrCreate_MFSRR:
++				AuDbg("%llu watermark\n",
++					  u.create->mfsrr_watermark);
++				break;
++			case AuWbrCreate_MFSRRV:
++			case AuWbrCreate_PMFSRRV:
++				AuDbg("%llu watermark, %d sec\n",
++					  u.create->mfsrr_watermark,
++					  u.create->mfs_second);
++				break;
++			}
++			break;
++		case Opt_wbr_copyup:
++			AuDbg("copyup %d, %s\n", opt->wbr_copyup,
++				  au_optstr_wbr_copyup(opt->wbr_copyup));
++			break;
++		case Opt_fhsm_sec:
++			AuDbg("fhsm_sec %u\n", opt->fhsm_second);
++			break;
++		case Opt_acl:
++			AuLabel(acl);
++			break;
++		case Opt_noacl:
++			AuLabel(noacl);
++			break;
++		default:
++			BUG();
++		}
++		opt++;
++	}
++#endif
++}
++
++void au_opts_free(struct au_opts *opts)
++{
++	struct au_opt *opt;
++
++	opt = opts->opt;
++	while (opt->type != Opt_tail) {
++		switch (opt->type) {
++		case Opt_add:
++		case Opt_append:
++		case Opt_prepend:
++			path_put(&opt->add.path);
++			break;
++		case Opt_del:
++		case Opt_idel:
++			path_put(&opt->del.h_path);
++			break;
++		case Opt_mod:
++		case Opt_imod:
++			dput(opt->mod.h_root);
++			break;
++		case Opt_xino:
++			fput(opt->xino.file);
++			break;
++		}
++		opt++;
++	}
++}
++
++static int opt_add(struct au_opt *opt, char *opt_str, unsigned long sb_flags,
++		   aufs_bindex_t bindex)
++{
++	int err;
++	struct au_opt_add *add = &opt->add;
++	char *p;
++
++	add->bindex = bindex;
++	add->perm = AuBrPerm_RO;
++	add->pathname = opt_str;
++	p = strchr(opt_str, '=');
++	if (p) {
++		*p++ = 0;
++		if (*p)
++			add->perm = br_perm_val(p);
++	}
++
++	err = vfsub_kern_path(add->pathname, lkup_dirflags, &add->path);
++	if (!err) {
++		if (!p) {
++			add->perm = AuBrPerm_RO;
++			if (au_test_fs_rr(add->path.dentry->d_sb))
++				add->perm = AuBrPerm_RR;
++			else if (!bindex && !(sb_flags & MS_RDONLY))
++				add->perm = AuBrPerm_RW;
++		}
++		opt->type = Opt_add;
++		goto out;
++	}
++	pr_err("lookup failed %s (%d)\n", add->pathname, err);
++	err = -EINVAL;
++
++out:
++	return err;
++}
++
++static int au_opts_parse_del(struct au_opt_del *del, substring_t args[])
++{
++	int err;
++
++	del->pathname = args[0].from;
++	AuDbg("del path %s\n", del->pathname);
++
++	err = vfsub_kern_path(del->pathname, lkup_dirflags, &del->h_path);
++	if (unlikely(err))
++		pr_err("lookup failed %s (%d)\n", del->pathname, err);
++
++	return err;
++}
++
++#if 0 /* reserved for future use */
++static int au_opts_parse_idel(struct super_block *sb, aufs_bindex_t bindex,
++			      struct au_opt_del *del, substring_t args[])
++{
++	int err;
++	struct dentry *root;
++
++	err = -EINVAL;
++	root = sb->s_root;
++	aufs_read_lock(root, AuLock_FLUSH);
++	if (bindex < 0 || au_sbend(sb) < bindex) {
++		pr_err("out of bounds, %d\n", bindex);
++		goto out;
++	}
++
++	err = 0;
++	del->h_path.dentry = dget(au_h_dptr(root, bindex));
++	del->h_path.mnt = mntget(au_sbr_mnt(sb, bindex));
++
++out:
++	aufs_read_unlock(root, !AuLock_IR);
++	return err;
++}
++#endif
++
++static int noinline_for_stack
++au_opts_parse_mod(struct au_opt_mod *mod, substring_t args[])
++{
++	int err;
++	struct path path;
++	char *p;
++
++	err = -EINVAL;
++	mod->path = args[0].from;
++	p = strchr(mod->path, '=');
++	if (unlikely(!p)) {
++		pr_err("no permssion %s\n", args[0].from);
++		goto out;
++	}
++
++	*p++ = 0;
++	err = vfsub_kern_path(mod->path, lkup_dirflags, &path);
++	if (unlikely(err)) {
++		pr_err("lookup failed %s (%d)\n", mod->path, err);
++		goto out;
++	}
++
++	mod->perm = br_perm_val(p);
++	AuDbg("mod path %s, perm 0x%x, %s\n", mod->path, mod->perm, p);
++	mod->h_root = dget(path.dentry);
++	path_put(&path);
++
++out:
++	return err;
++}
++
++#if 0 /* reserved for future use */
++static int au_opts_parse_imod(struct super_block *sb, aufs_bindex_t bindex,
++			      struct au_opt_mod *mod, substring_t args[])
++{
++	int err;
++	struct dentry *root;
++
++	err = -EINVAL;
++	root = sb->s_root;
++	aufs_read_lock(root, AuLock_FLUSH);
++	if (bindex < 0 || au_sbend(sb) < bindex) {
++		pr_err("out of bounds, %d\n", bindex);
++		goto out;
++	}
++
++	err = 0;
++	mod->perm = br_perm_val(args[1].from);
++	AuDbg("mod path %s, perm 0x%x, %s\n",
++	      mod->path, mod->perm, args[1].from);
++	mod->h_root = dget(au_h_dptr(root, bindex));
++
++out:
++	aufs_read_unlock(root, !AuLock_IR);
++	return err;
++}
++#endif
++
++static int au_opts_parse_xino(struct super_block *sb, struct au_opt_xino *xino,
++			      substring_t args[])
++{
++	int err;
++	struct file *file;
++
++	file = au_xino_create(sb, args[0].from, /*silent*/0);
++	err = PTR_ERR(file);
++	if (IS_ERR(file))
++		goto out;
++
++	err = -EINVAL;
++	if (unlikely(file->f_path.dentry->d_sb == sb)) {
++		fput(file);
++		pr_err("%s must be outside\n", args[0].from);
++		goto out;
++	}
++
++	err = 0;
++	xino->file = file;
++	xino->path = args[0].from;
++
++out:
++	return err;
++}
++
++static int noinline_for_stack
++au_opts_parse_xino_itrunc_path(struct super_block *sb,
++			       struct au_opt_xino_itrunc *xino_itrunc,
++			       substring_t args[])
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct path path;
++	struct dentry *root;
++
++	err = vfsub_kern_path(args[0].from, lkup_dirflags, &path);
++	if (unlikely(err)) {
++		pr_err("lookup failed %s (%d)\n", args[0].from, err);
++		goto out;
++	}
++
++	xino_itrunc->bindex = -1;
++	root = sb->s_root;
++	aufs_read_lock(root, AuLock_FLUSH);
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		if (au_h_dptr(root, bindex) == path.dentry) {
++			xino_itrunc->bindex = bindex;
++			break;
++		}
++	}
++	aufs_read_unlock(root, !AuLock_IR);
++	path_put(&path);
++
++	if (unlikely(xino_itrunc->bindex < 0)) {
++		pr_err("no such branch %s\n", args[0].from);
++		err = -EINVAL;
++	}
++
++out:
++	return err;
++}
++
++/* called without aufs lock */
++int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts)
++{
++	int err, n, token;
++	aufs_bindex_t bindex;
++	unsigned char skipped;
++	struct dentry *root;
++	struct au_opt *opt, *opt_tail;
++	char *opt_str;
++	/* reduce the stack space */
++	union {
++		struct au_opt_xino_itrunc *xino_itrunc;
++		struct au_opt_wbr_create *create;
++	} u;
++	struct {
++		substring_t args[MAX_OPT_ARGS];
++	} *a;
++
++	err = -ENOMEM;
++	a = kmalloc(sizeof(*a), GFP_NOFS);
++	if (unlikely(!a))
++		goto out;
++
++	root = sb->s_root;
++	err = 0;
++	bindex = 0;
++	opt = opts->opt;
++	opt_tail = opt + opts->max_opt - 1;
++	opt->type = Opt_tail;
++	while (!err && (opt_str = strsep(&str, ",")) && *opt_str) {
++		err = -EINVAL;
++		skipped = 0;
++		token = match_token(opt_str, options, a->args);
++		switch (token) {
++		case Opt_br:
++			err = 0;
++			while (!err && (opt_str = strsep(&a->args[0].from, ":"))
++			       && *opt_str) {
++				err = opt_add(opt, opt_str, opts->sb_flags,
++					      bindex++);
++				if (unlikely(!err && ++opt > opt_tail)) {
++					err = -E2BIG;
++					break;
++				}
++				opt->type = Opt_tail;
++				skipped = 1;
++			}
++			break;
++		case Opt_add:
++			if (unlikely(match_int(&a->args[0], &n))) {
++				pr_err("bad integer in %s\n", opt_str);
++				break;
++			}
++			bindex = n;
++			err = opt_add(opt, a->args[1].from, opts->sb_flags,
++				      bindex);
++			if (!err)
++				opt->type = token;
++			break;
++		case Opt_append:
++			err = opt_add(opt, a->args[0].from, opts->sb_flags,
++				      /*dummy bindex*/1);
++			if (!err)
++				opt->type = token;
++			break;
++		case Opt_prepend:
++			err = opt_add(opt, a->args[0].from, opts->sb_flags,
++				      /*bindex*/0);
++			if (!err)
++				opt->type = token;
++			break;
++		case Opt_del:
++			err = au_opts_parse_del(&opt->del, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++#if 0 /* reserved for future use */
++		case Opt_idel:
++			del->pathname = "(indexed)";
++			if (unlikely(match_int(&args[0], &n))) {
++				pr_err("bad integer in %s\n", opt_str);
++				break;
++			}
++			err = au_opts_parse_idel(sb, n, &opt->del, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++#endif
++		case Opt_mod:
++			err = au_opts_parse_mod(&opt->mod, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++#ifdef IMOD /* reserved for future use */
++		case Opt_imod:
++			u.mod->path = "(indexed)";
++			if (unlikely(match_int(&a->args[0], &n))) {
++				pr_err("bad integer in %s\n", opt_str);
++				break;
++			}
++			err = au_opts_parse_imod(sb, n, &opt->mod, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++#endif
++		case Opt_xino:
++			err = au_opts_parse_xino(sb, &opt->xino, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++
++		case Opt_trunc_xino_path:
++			err = au_opts_parse_xino_itrunc_path
++				(sb, &opt->xino_itrunc, a->args);
++			if (!err)
++				opt->type = token;
++			break;
++
++		case Opt_itrunc_xino:
++			u.xino_itrunc = &opt->xino_itrunc;
++			if (unlikely(match_int(&a->args[0], &n))) {
++				pr_err("bad integer in %s\n", opt_str);
++				break;
++			}
++			u.xino_itrunc->bindex = n;
++			aufs_read_lock(root, AuLock_FLUSH);
++			if (n < 0 || au_sbend(sb) < n) {
++				pr_err("out of bounds, %d\n", n);
++				aufs_read_unlock(root, !AuLock_IR);
++				break;
++			}
++			aufs_read_unlock(root, !AuLock_IR);
++			err = 0;
++			opt->type = token;
++			break;
++
++		case Opt_dirwh:
++			if (unlikely(match_int(&a->args[0], &opt->dirwh)))
++				break;
++			err = 0;
++			opt->type = token;
++			break;
++
++		case Opt_rdcache:
++			if (unlikely(match_int(&a->args[0], &n))) {
++				pr_err("bad integer in %s\n", opt_str);
++				break;
++			}
++			if (unlikely(n > AUFS_RDCACHE_MAX)) {
++				pr_err("rdcache must be smaller than %d\n",
++				       AUFS_RDCACHE_MAX);
++				break;
++			}
++			opt->rdcache = n;
++			err = 0;
++			opt->type = token;
++			break;
++		case Opt_rdblk:
++			if (unlikely(match_int(&a->args[0], &n)
++				     || n < 0
++				     || n > KMALLOC_MAX_SIZE)) {
++				pr_err("bad integer in %s\n", opt_str);
++				break;
++			}
++			if (unlikely(n && n < NAME_MAX)) {
++				pr_err("rdblk must be larger than %d\n",
++				       NAME_MAX);
++				break;
++			}
++			opt->rdblk = n;
++			err = 0;
++			opt->type = token;
++			break;
++		case Opt_rdhash:
++			if (unlikely(match_int(&a->args[0], &n)
++				     || n < 0
++				     || n * sizeof(struct hlist_head)
++				     > KMALLOC_MAX_SIZE)) {
++				pr_err("bad integer in %s\n", opt_str);
++				break;
++			}
++			opt->rdhash = n;
++			err = 0;
++			opt->type = token;
++			break;
++
++		case Opt_trunc_xino:
++		case Opt_notrunc_xino:
++		case Opt_noxino:
++		case Opt_trunc_xib:
++		case Opt_notrunc_xib:
++		case Opt_shwh:
++		case Opt_noshwh:
++		case Opt_dirperm1:
++		case Opt_nodirperm1:
++		case Opt_plink:
++		case Opt_noplink:
++		case Opt_list_plink:
++		case Opt_dio:
++		case Opt_nodio:
++		case Opt_diropq_a:
++		case Opt_diropq_w:
++		case Opt_warn_perm:
++		case Opt_nowarn_perm:
++		case Opt_verbose:
++		case Opt_noverbose:
++		case Opt_sum:
++		case Opt_nosum:
++		case Opt_wsum:
++		case Opt_rdblk_def:
++		case Opt_rdhash_def:
++		case Opt_acl:
++		case Opt_noacl:
++			err = 0;
++			opt->type = token;
++			break;
++
++		case Opt_udba:
++			opt->udba = udba_val(a->args[0].from);
++			if (opt->udba >= 0) {
++				err = 0;
++				opt->type = token;
++			} else
++				pr_err("wrong value, %s\n", opt_str);
++			break;
++
++		case Opt_wbr_create:
++			u.create = &opt->wbr_create;
++			u.create->wbr_create
++				= au_wbr_create_val(a->args[0].from, u.create);
++			if (u.create->wbr_create >= 0) {
++				err = 0;
++				opt->type = token;
++			} else
++				pr_err("wrong value, %s\n", opt_str);
++			break;
++		case Opt_wbr_copyup:
++			opt->wbr_copyup = au_wbr_copyup_val(a->args[0].from);
++			if (opt->wbr_copyup >= 0) {
++				err = 0;
++				opt->type = token;
++			} else
++				pr_err("wrong value, %s\n", opt_str);
++			break;
++
++		case Opt_fhsm_sec:
++			if (unlikely(match_int(&a->args[0], &n)
++				     || n < 0)) {
++				pr_err("bad integer in %s\n", opt_str);
++				break;
++			}
++			if (sysaufs_brs) {
++				opt->fhsm_second = n;
++				opt->type = token;
++			} else
++				pr_warn("ignored %s\n", opt_str);
++			err = 0;
++			break;
++
++		case Opt_ignore:
++			pr_warn("ignored %s\n", opt_str);
++			/*FALLTHROUGH*/
++		case Opt_ignore_silent:
++			skipped = 1;
++			err = 0;
++			break;
++		case Opt_err:
++			pr_err("unknown option %s\n", opt_str);
++			break;
++		}
++
++		if (!err && !skipped) {
++			if (unlikely(++opt > opt_tail)) {
++				err = -E2BIG;
++				opt--;
++				opt->type = Opt_tail;
++				break;
++			}
++			opt->type = Opt_tail;
++		}
++	}
++
++	kfree(a);
++	dump_opts(opts);
++	if (unlikely(err))
++		au_opts_free(opts);
++
++out:
++	return err;
++}
++
++static int au_opt_wbr_create(struct super_block *sb,
++			     struct au_opt_wbr_create *create)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++
++	SiMustWriteLock(sb);
++
++	err = 1; /* handled */
++	sbinfo = au_sbi(sb);
++	if (sbinfo->si_wbr_create_ops->fin) {
++		err = sbinfo->si_wbr_create_ops->fin(sb);
++		if (!err)
++			err = 1;
++	}
++
++	sbinfo->si_wbr_create = create->wbr_create;
++	sbinfo->si_wbr_create_ops = au_wbr_create_ops + create->wbr_create;
++	switch (create->wbr_create) {
++	case AuWbrCreate_MFSRRV:
++	case AuWbrCreate_MFSRR:
++	case AuWbrCreate_PMFSRR:
++	case AuWbrCreate_PMFSRRV:
++		sbinfo->si_wbr_mfs.mfsrr_watermark = create->mfsrr_watermark;
++		/*FALLTHROUGH*/
++	case AuWbrCreate_MFS:
++	case AuWbrCreate_MFSV:
++	case AuWbrCreate_PMFS:
++	case AuWbrCreate_PMFSV:
++		sbinfo->si_wbr_mfs.mfs_expire
++			= msecs_to_jiffies(create->mfs_second * MSEC_PER_SEC);
++		break;
++	}
++
++	if (sbinfo->si_wbr_create_ops->init)
++		sbinfo->si_wbr_create_ops->init(sb); /* ignore */
++
++	return err;
++}
++
++/*
++ * returns,
++ * plus: processed without an error
++ * zero: unprocessed
++ */
++static int au_opt_simple(struct super_block *sb, struct au_opt *opt,
++			 struct au_opts *opts)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++
++	SiMustWriteLock(sb);
++
++	err = 1; /* handled */
++	sbinfo = au_sbi(sb);
++	switch (opt->type) {
++	case Opt_udba:
++		sbinfo->si_mntflags &= ~AuOptMask_UDBA;
++		sbinfo->si_mntflags |= opt->udba;
++		opts->given_udba |= opt->udba;
++		break;
++
++	case Opt_plink:
++		au_opt_set(sbinfo->si_mntflags, PLINK);
++		break;
++	case Opt_noplink:
++		if (au_opt_test(sbinfo->si_mntflags, PLINK))
++			au_plink_put(sb, /*verbose*/1);
++		au_opt_clr(sbinfo->si_mntflags, PLINK);
++		break;
++	case Opt_list_plink:
++		if (au_opt_test(sbinfo->si_mntflags, PLINK))
++			au_plink_list(sb);
++		break;
++
++	case Opt_dio:
++		au_opt_set(sbinfo->si_mntflags, DIO);
++		au_fset_opts(opts->flags, REFRESH_DYAOP);
++		break;
++	case Opt_nodio:
++		au_opt_clr(sbinfo->si_mntflags, DIO);
++		au_fset_opts(opts->flags, REFRESH_DYAOP);
++		break;
++
++	case Opt_fhsm_sec:
++		au_fhsm_set(sbinfo, opt->fhsm_second);
++		break;
++
++	case Opt_diropq_a:
++		au_opt_set(sbinfo->si_mntflags, ALWAYS_DIROPQ);
++		break;
++	case Opt_diropq_w:
++		au_opt_clr(sbinfo->si_mntflags, ALWAYS_DIROPQ);
++		break;
++
++	case Opt_warn_perm:
++		au_opt_set(sbinfo->si_mntflags, WARN_PERM);
++		break;
++	case Opt_nowarn_perm:
++		au_opt_clr(sbinfo->si_mntflags, WARN_PERM);
++		break;
++
++	case Opt_verbose:
++		au_opt_set(sbinfo->si_mntflags, VERBOSE);
++		break;
++	case Opt_noverbose:
++		au_opt_clr(sbinfo->si_mntflags, VERBOSE);
++		break;
++
++	case Opt_sum:
++		au_opt_set(sbinfo->si_mntflags, SUM);
++		break;
++	case Opt_wsum:
++		au_opt_clr(sbinfo->si_mntflags, SUM);
++		au_opt_set(sbinfo->si_mntflags, SUM_W);
++	case Opt_nosum:
++		au_opt_clr(sbinfo->si_mntflags, SUM);
++		au_opt_clr(sbinfo->si_mntflags, SUM_W);
++		break;
++
++	case Opt_wbr_create:
++		err = au_opt_wbr_create(sb, &opt->wbr_create);
++		break;
++	case Opt_wbr_copyup:
++		sbinfo->si_wbr_copyup = opt->wbr_copyup;
++		sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + opt->wbr_copyup;
++		break;
++
++	case Opt_dirwh:
++		sbinfo->si_dirwh = opt->dirwh;
++		break;
++
++	case Opt_rdcache:
++		sbinfo->si_rdcache
++			= msecs_to_jiffies(opt->rdcache * MSEC_PER_SEC);
++		break;
++	case Opt_rdblk:
++		sbinfo->si_rdblk = opt->rdblk;
++		break;
++	case Opt_rdblk_def:
++		sbinfo->si_rdblk = AUFS_RDBLK_DEF;
++		break;
++	case Opt_rdhash:
++		sbinfo->si_rdhash = opt->rdhash;
++		break;
++	case Opt_rdhash_def:
++		sbinfo->si_rdhash = AUFS_RDHASH_DEF;
++		break;
++
++	case Opt_shwh:
++		au_opt_set(sbinfo->si_mntflags, SHWH);
++		break;
++	case Opt_noshwh:
++		au_opt_clr(sbinfo->si_mntflags, SHWH);
++		break;
++
++	case Opt_dirperm1:
++		au_opt_set(sbinfo->si_mntflags, DIRPERM1);
++		break;
++	case Opt_nodirperm1:
++		au_opt_clr(sbinfo->si_mntflags, DIRPERM1);
++		break;
++
++	case Opt_trunc_xino:
++		au_opt_set(sbinfo->si_mntflags, TRUNC_XINO);
++		break;
++	case Opt_notrunc_xino:
++		au_opt_clr(sbinfo->si_mntflags, TRUNC_XINO);
++		break;
++
++	case Opt_trunc_xino_path:
++	case Opt_itrunc_xino:
++		err = au_xino_trunc(sb, opt->xino_itrunc.bindex);
++		if (!err)
++			err = 1;
++		break;
++
++	case Opt_trunc_xib:
++		au_fset_opts(opts->flags, TRUNC_XIB);
++		break;
++	case Opt_notrunc_xib:
++		au_fclr_opts(opts->flags, TRUNC_XIB);
++		break;
++
++	case Opt_acl:
++		sb->s_flags |= MS_POSIXACL;
++		break;
++	case Opt_noacl:
++		sb->s_flags &= ~MS_POSIXACL;
++		break;
++
++	default:
++		err = 0;
++		break;
++	}
++
++	return err;
++}
++
++/*
++ * returns tri-state.
++ * plus: processed without an error
++ * zero: unprocessed
++ * minus: error
++ */
++static int au_opt_br(struct super_block *sb, struct au_opt *opt,
++		     struct au_opts *opts)
++{
++	int err, do_refresh;
++
++	err = 0;
++	switch (opt->type) {
++	case Opt_append:
++		opt->add.bindex = au_sbend(sb) + 1;
++		if (opt->add.bindex < 0)
++			opt->add.bindex = 0;
++		goto add;
++	case Opt_prepend:
++		opt->add.bindex = 0;
++	add: /* indented label */
++	case Opt_add:
++		err = au_br_add(sb, &opt->add,
++				au_ftest_opts(opts->flags, REMOUNT));
++		if (!err) {
++			err = 1;
++			au_fset_opts(opts->flags, REFRESH);
++		}
++		break;
++
++	case Opt_del:
++	case Opt_idel:
++		err = au_br_del(sb, &opt->del,
++				au_ftest_opts(opts->flags, REMOUNT));
++		if (!err) {
++			err = 1;
++			au_fset_opts(opts->flags, TRUNC_XIB);
++			au_fset_opts(opts->flags, REFRESH);
++		}
++		break;
++
++	case Opt_mod:
++	case Opt_imod:
++		err = au_br_mod(sb, &opt->mod,
++				au_ftest_opts(opts->flags, REMOUNT),
++				&do_refresh);
++		if (!err) {
++			err = 1;
++			if (do_refresh)
++				au_fset_opts(opts->flags, REFRESH);
++		}
++		break;
++	}
++
++	return err;
++}
++
++static int au_opt_xino(struct super_block *sb, struct au_opt *opt,
++		       struct au_opt_xino **opt_xino,
++		       struct au_opts *opts)
++{
++	int err;
++	aufs_bindex_t bend, bindex;
++	struct dentry *root, *parent, *h_root;
++
++	err = 0;
++	switch (opt->type) {
++	case Opt_xino:
++		err = au_xino_set(sb, &opt->xino,
++				  !!au_ftest_opts(opts->flags, REMOUNT));
++		if (unlikely(err))
++			break;
++
++		*opt_xino = &opt->xino;
++		au_xino_brid_set(sb, -1);
++
++		/* safe d_parent access */
++		parent = opt->xino.file->f_path.dentry->d_parent;
++		root = sb->s_root;
++		bend = au_sbend(sb);
++		for (bindex = 0; bindex <= bend; bindex++) {
++			h_root = au_h_dptr(root, bindex);
++			if (h_root == parent) {
++				au_xino_brid_set(sb, au_sbr_id(sb, bindex));
++				break;
++			}
++		}
++		break;
++
++	case Opt_noxino:
++		au_xino_clr(sb);
++		au_xino_brid_set(sb, -1);
++		*opt_xino = (void *)-1;
++		break;
++	}
++
++	return err;
++}
++
++int au_opts_verify(struct super_block *sb, unsigned long sb_flags,
++		   unsigned int pending)
++{
++	int err, fhsm;
++	aufs_bindex_t bindex, bend;
++	unsigned char do_plink, skip, do_free;
++	struct au_branch *br;
++	struct au_wbr *wbr;
++	struct dentry *root;
++	struct inode *dir, *h_dir;
++	struct au_sbinfo *sbinfo;
++	struct au_hinode *hdir;
++
++	SiMustAnyLock(sb);
++
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!(sbinfo->si_mntflags & AuOptMask_UDBA));
++
++	if (!(sb_flags & MS_RDONLY)) {
++		if (unlikely(!au_br_writable(au_sbr_perm(sb, 0))))
++			pr_warn("first branch should be rw\n");
++		if (unlikely(au_opt_test(sbinfo->si_mntflags, SHWH)))
++			pr_warn("shwh should be used with ro\n");
++	}
++
++	if (au_opt_test((sbinfo->si_mntflags | pending), UDBA_HNOTIFY)
++	    && !au_opt_test(sbinfo->si_mntflags, XINO))
++		pr_warn("udba=*notify requires xino\n");
++
++	if (au_opt_test(sbinfo->si_mntflags, DIRPERM1))
++		pr_warn("dirperm1 breaks the protection"
++			" by the permission bits on the lower branch\n");
++
++	err = 0;
++	fhsm = 0;
++	root = sb->s_root;
++	dir = root->d_inode;
++	do_plink = !!au_opt_test(sbinfo->si_mntflags, PLINK);
++	bend = au_sbend(sb);
++	for (bindex = 0; !err && bindex <= bend; bindex++) {
++		skip = 0;
++		h_dir = au_h_iptr(dir, bindex);
++		br = au_sbr(sb, bindex);
++
++		if ((br->br_perm & AuBrAttr_ICEX)
++		    && !h_dir->i_op->listxattr)
++			br->br_perm &= ~AuBrAttr_ICEX;
++#if 0
++		if ((br->br_perm & AuBrAttr_ICEX_SEC)
++		    && (au_br_sb(br)->s_flags & MS_NOSEC))
++			br->br_perm &= ~AuBrAttr_ICEX_SEC;
++#endif
++
++		do_free = 0;
++		wbr = br->br_wbr;
++		if (wbr)
++			wbr_wh_read_lock(wbr);
++
++		if (!au_br_writable(br->br_perm)) {
++			do_free = !!wbr;
++			skip = (!wbr
++				|| (!wbr->wbr_whbase
++				    && !wbr->wbr_plink
++				    && !wbr->wbr_orph));
++		} else if (!au_br_wh_linkable(br->br_perm)) {
++			/* skip = (!br->br_whbase && !br->br_orph); */
++			skip = (!wbr || !wbr->wbr_whbase);
++			if (skip && wbr) {
++				if (do_plink)
++					skip = !!wbr->wbr_plink;
++				else
++					skip = !wbr->wbr_plink;
++			}
++		} else {
++			/* skip = (br->br_whbase && br->br_ohph); */
++			skip = (wbr && wbr->wbr_whbase);
++			if (skip) {
++				if (do_plink)
++					skip = !!wbr->wbr_plink;
++				else
++					skip = !wbr->wbr_plink;
++			}
++		}
++		if (wbr)
++			wbr_wh_read_unlock(wbr);
++
++		if (au_br_fhsm(br->br_perm)) {
++			fhsm++;
++			AuDebugOn(!br->br_fhsm);
++		}
++
++		if (skip)
++			continue;
++
++		hdir = au_hi(dir, bindex);
++		au_hn_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++		if (wbr)
++			wbr_wh_write_lock(wbr);
++		err = au_wh_init(br, sb);
++		if (wbr)
++			wbr_wh_write_unlock(wbr);
++		au_hn_imtx_unlock(hdir);
++
++		if (!err && do_free) {
++			kfree(wbr);
++			br->br_wbr = NULL;
++		}
++	}
++
++	if (fhsm >= 2) {
++		au_fset_si(sbinfo, FHSM);
++		for (bindex = bend; bindex >= 0; bindex--) {
++			br = au_sbr(sb, bindex);
++			if (au_br_fhsm(br->br_perm)) {
++				au_fhsm_set_bottom(sb, bindex);
++				break;
++			}
++		}
++	} else {
++		au_fclr_si(sbinfo, FHSM);
++		au_fhsm_set_bottom(sb, -1);
++	}
++
++	return err;
++}
++
++int au_opts_mount(struct super_block *sb, struct au_opts *opts)
++{
++	int err;
++	unsigned int tmp;
++	aufs_bindex_t bindex, bend;
++	struct au_opt *opt;
++	struct au_opt_xino *opt_xino, xino;
++	struct au_sbinfo *sbinfo;
++	struct au_branch *br;
++	struct inode *dir;
++
++	SiMustWriteLock(sb);
++
++	err = 0;
++	opt_xino = NULL;
++	opt = opts->opt;
++	while (err >= 0 && opt->type != Opt_tail)
++		err = au_opt_simple(sb, opt++, opts);
++	if (err > 0)
++		err = 0;
++	else if (unlikely(err < 0))
++		goto out;
++
++	/* disable xino and udba temporary */
++	sbinfo = au_sbi(sb);
++	tmp = sbinfo->si_mntflags;
++	au_opt_clr(sbinfo->si_mntflags, XINO);
++	au_opt_set_udba(sbinfo->si_mntflags, UDBA_REVAL);
++
++	opt = opts->opt;
++	while (err >= 0 && opt->type != Opt_tail)
++		err = au_opt_br(sb, opt++, opts);
++	if (err > 0)
++		err = 0;
++	else if (unlikely(err < 0))
++		goto out;
++
++	bend = au_sbend(sb);
++	if (unlikely(bend < 0)) {
++		err = -EINVAL;
++		pr_err("no branches\n");
++		goto out;
++	}
++
++	if (au_opt_test(tmp, XINO))
++		au_opt_set(sbinfo->si_mntflags, XINO);
++	opt = opts->opt;
++	while (!err && opt->type != Opt_tail)
++		err = au_opt_xino(sb, opt++, &opt_xino, opts);
++	if (unlikely(err))
++		goto out;
++
++	err = au_opts_verify(sb, sb->s_flags, tmp);
++	if (unlikely(err))
++		goto out;
++
++	/* restore xino */
++	if (au_opt_test(tmp, XINO) && !opt_xino) {
++		xino.file = au_xino_def(sb);
++		err = PTR_ERR(xino.file);
++		if (IS_ERR(xino.file))
++			goto out;
++
++		err = au_xino_set(sb, &xino, /*remount*/0);
++		fput(xino.file);
++		if (unlikely(err))
++			goto out;
++	}
++
++	/* restore udba */
++	tmp &= AuOptMask_UDBA;
++	sbinfo->si_mntflags &= ~AuOptMask_UDBA;
++	sbinfo->si_mntflags |= tmp;
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		err = au_hnotify_reset_br(tmp, br, br->br_perm);
++		if (unlikely(err))
++			AuIOErr("hnotify failed on br %d, %d, ignored\n",
++				bindex, err);
++		/* go on even if err */
++	}
++	if (au_opt_test(tmp, UDBA_HNOTIFY)) {
++		dir = sb->s_root->d_inode;
++		au_hn_reset(dir, au_hi_flags(dir, /*isdir*/1) & ~AuHi_XINO);
++	}
++
++out:
++	return err;
++}
++
++int au_opts_remount(struct super_block *sb, struct au_opts *opts)
++{
++	int err, rerr;
++	struct inode *dir;
++	struct au_opt_xino *opt_xino;
++	struct au_opt *opt;
++	struct au_sbinfo *sbinfo;
++
++	SiMustWriteLock(sb);
++
++	dir = sb->s_root->d_inode;
++	sbinfo = au_sbi(sb);
++	err = 0;
++	opt_xino = NULL;
++	opt = opts->opt;
++	while (err >= 0 && opt->type != Opt_tail) {
++		err = au_opt_simple(sb, opt, opts);
++		if (!err)
++			err = au_opt_br(sb, opt, opts);
++		if (!err)
++			err = au_opt_xino(sb, opt, &opt_xino, opts);
++		opt++;
++	}
++	if (err > 0)
++		err = 0;
++	AuTraceErr(err);
++	/* go on even err */
++
++	rerr = au_opts_verify(sb, opts->sb_flags, /*pending*/0);
++	if (unlikely(rerr && !err))
++		err = rerr;
++
++	if (au_ftest_opts(opts->flags, TRUNC_XIB)) {
++		rerr = au_xib_trunc(sb);
++		if (unlikely(rerr && !err))
++			err = rerr;
++	}
++
++	/* will be handled by the caller */
++	if (!au_ftest_opts(opts->flags, REFRESH)
++	    && (opts->given_udba || au_opt_test(sbinfo->si_mntflags, XINO)))
++		au_fset_opts(opts->flags, REFRESH);
++
++	AuDbg("status 0x%x\n", opts->flags);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++unsigned int au_opt_udba(struct super_block *sb)
++{
++	return au_mntflags(sb) & AuOptMask_UDBA;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/opts.h linux-4.0.4/fs/aufs/opts.h
+--- linux-4.0.4.orig/fs/aufs/opts.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/opts.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,197 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * mount options/flags
++ */
++
++#ifndef __AUFS_OPTS_H__
++#define __AUFS_OPTS_H__
++
++#ifdef __KERNEL__
++
++#include <linux/path.h>
++
++struct file;
++struct super_block;
++
++/* ---------------------------------------------------------------------- */
++
++/* mount flags */
++#define AuOpt_XINO		1		/* external inode number bitmap
++						   and translation table */
++#define AuOpt_TRUNC_XINO	(1 << 1)	/* truncate xino files */
++#define AuOpt_UDBA_NONE		(1 << 2)	/* users direct branch access */
++#define AuOpt_UDBA_REVAL	(1 << 3)
++#define AuOpt_UDBA_HNOTIFY	(1 << 4)
++#define AuOpt_SHWH		(1 << 5)	/* show whiteout */
++#define AuOpt_PLINK		(1 << 6)	/* pseudo-link */
++#define AuOpt_DIRPERM1		(1 << 7)	/* ignore the lower dir's perm
++						   bits */
++#define AuOpt_ALWAYS_DIROPQ	(1 << 9)	/* policy to creating diropq */
++#define AuOpt_SUM		(1 << 10)	/* summation for statfs(2) */
++#define AuOpt_SUM_W		(1 << 11)	/* unimplemented */
++#define AuOpt_WARN_PERM		(1 << 12)	/* warn when add-branch */
++#define AuOpt_VERBOSE		(1 << 13)	/* busy inode when del-branch */
++#define AuOpt_DIO		(1 << 14)	/* direct io */
++
++#ifndef CONFIG_AUFS_HNOTIFY
++#undef AuOpt_UDBA_HNOTIFY
++#define AuOpt_UDBA_HNOTIFY	0
++#endif
++#ifndef CONFIG_AUFS_SHWH
++#undef AuOpt_SHWH
++#define AuOpt_SHWH		0
++#endif
++
++#define AuOpt_Def	(AuOpt_XINO \
++			 | AuOpt_UDBA_REVAL \
++			 | AuOpt_PLINK \
++			 /* | AuOpt_DIRPERM1 */ \
++			 | AuOpt_WARN_PERM)
++#define AuOptMask_UDBA	(AuOpt_UDBA_NONE \
++			 | AuOpt_UDBA_REVAL \
++			 | AuOpt_UDBA_HNOTIFY)
++
++#define au_opt_test(flags, name)	(flags & AuOpt_##name)
++#define au_opt_set(flags, name) do { \
++	BUILD_BUG_ON(AuOpt_##name & AuOptMask_UDBA); \
++	((flags) |= AuOpt_##name); \
++} while (0)
++#define au_opt_set_udba(flags, name) do { \
++	(flags) &= ~AuOptMask_UDBA; \
++	((flags) |= AuOpt_##name); \
++} while (0)
++#define au_opt_clr(flags, name) do { \
++	((flags) &= ~AuOpt_##name); \
++} while (0)
++
++static inline unsigned int au_opts_plink(unsigned int mntflags)
++{
++#ifdef CONFIG_PROC_FS
++	return mntflags;
++#else
++	return mntflags & ~AuOpt_PLINK;
++#endif
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* policies to select one among multiple writable branches */
++enum {
++	AuWbrCreate_TDP,	/* top down parent */
++	AuWbrCreate_RR,		/* round robin */
++	AuWbrCreate_MFS,	/* most free space */
++	AuWbrCreate_MFSV,	/* mfs with seconds */
++	AuWbrCreate_MFSRR,	/* mfs then rr */
++	AuWbrCreate_MFSRRV,	/* mfs then rr with seconds */
++	AuWbrCreate_PMFS,	/* parent and mfs */
++	AuWbrCreate_PMFSV,	/* parent and mfs with seconds */
++	AuWbrCreate_PMFSRR,	/* parent, mfs and round-robin */
++	AuWbrCreate_PMFSRRV,	/* plus seconds */
++
++	AuWbrCreate_Def = AuWbrCreate_TDP
++};
++
++enum {
++	AuWbrCopyup_TDP,	/* top down parent */
++	AuWbrCopyup_BUP,	/* bottom up parent */
++	AuWbrCopyup_BU,		/* bottom up */
++
++	AuWbrCopyup_Def = AuWbrCopyup_TDP
++};
++
++/* ---------------------------------------------------------------------- */
++
++struct au_opt_add {
++	aufs_bindex_t	bindex;
++	char		*pathname;
++	int		perm;
++	struct path	path;
++};
++
++struct au_opt_del {
++	char		*pathname;
++	struct path	h_path;
++};
++
++struct au_opt_mod {
++	char		*path;
++	int		perm;
++	struct dentry	*h_root;
++};
++
++struct au_opt_xino {
++	char		*path;
++	struct file	*file;
++};
++
++struct au_opt_xino_itrunc {
++	aufs_bindex_t	bindex;
++};
++
++struct au_opt_wbr_create {
++	int			wbr_create;
++	int			mfs_second;
++	unsigned long long	mfsrr_watermark;
++};
++
++struct au_opt {
++	int type;
++	union {
++		struct au_opt_xino	xino;
++		struct au_opt_xino_itrunc xino_itrunc;
++		struct au_opt_add	add;
++		struct au_opt_del	del;
++		struct au_opt_mod	mod;
++		int			dirwh;
++		int			rdcache;
++		unsigned int		rdblk;
++		unsigned int		rdhash;
++		int			udba;
++		struct au_opt_wbr_create wbr_create;
++		int			wbr_copyup;
++		unsigned int		fhsm_second;
++	};
++};
++
++/* opts flags */
++#define AuOpts_REMOUNT		1
++#define AuOpts_REFRESH		(1 << 1)
++#define AuOpts_TRUNC_XIB	(1 << 2)
++#define AuOpts_REFRESH_DYAOP	(1 << 3)
++#define au_ftest_opts(flags, name)	((flags) & AuOpts_##name)
++#define au_fset_opts(flags, name) \
++	do { (flags) |= AuOpts_##name; } while (0)
++#define au_fclr_opts(flags, name) \
++	do { (flags) &= ~AuOpts_##name; } while (0)
++
++struct au_opts {
++	struct au_opt	*opt;
++	int		max_opt;
++
++	unsigned int	given_udba;
++	unsigned int	flags;
++	unsigned long	sb_flags;
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* opts.c */
++void au_optstr_br_perm(au_br_perm_str_t *str, int perm);
++const char *au_optstr_udba(int udba);
++const char *au_optstr_wbr_copyup(int wbr_copyup);
++const char *au_optstr_wbr_create(int wbr_create);
++
++void au_opts_free(struct au_opts *opts);
++int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts);
++int au_opts_verify(struct super_block *sb, unsigned long sb_flags,
++		   unsigned int pending);
++int au_opts_mount(struct super_block *sb, struct au_opts *opts);
++int au_opts_remount(struct super_block *sb, struct au_opts *opts);
++
++unsigned int au_opt_udba(struct super_block *sb);
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_OPTS_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/plink.c linux-4.0.4/fs/aufs/plink.c
+--- linux-4.0.4.orig/fs/aufs/plink.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/plink.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,519 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * pseudo-link
++ */
++
++#include "aufs.h"
++
++/*
++ * the pseudo-link maintenance mode.
++ * during a user process maintains the pseudo-links,
++ * prohibit adding a new plink and branch manipulation.
++ *
++ * Flags
++ * NOPLM:
++ *	For entry functions which will handle plink, and i_mutex is already held
++ *	in VFS.
++ *	They cannot wait and should return an error at once.
++ *	Callers has to check the error.
++ * NOPLMW:
++ *	For entry functions which will handle plink, but i_mutex is not held
++ *	in VFS.
++ *	They can wait the plink maintenance mode to finish.
++ *
++ * They behave like F_SETLK and F_SETLKW.
++ * If the caller never handle plink, then both flags are unnecessary.
++ */
++
++int au_plink_maint(struct super_block *sb, int flags)
++{
++	int err;
++	pid_t pid, ppid;
++	struct au_sbinfo *sbi;
++
++	SiMustAnyLock(sb);
++
++	err = 0;
++	if (!au_opt_test(au_mntflags(sb), PLINK))
++		goto out;
++
++	sbi = au_sbi(sb);
++	pid = sbi->si_plink_maint_pid;
++	if (!pid || pid == current->pid)
++		goto out;
++
++	/* todo: it highly depends upon /sbin/mount.aufs */
++	rcu_read_lock();
++	ppid = task_pid_vnr(rcu_dereference(current->real_parent));
++	rcu_read_unlock();
++	if (pid == ppid)
++		goto out;
++
++	if (au_ftest_lock(flags, NOPLMW)) {
++		/* if there is no i_mutex lock in VFS, we don't need to wait */
++		/* AuDebugOn(!lockdep_depth(current)); */
++		while (sbi->si_plink_maint_pid) {
++			si_read_unlock(sb);
++			/* gave up wake_up_bit() */
++			wait_event(sbi->si_plink_wq, !sbi->si_plink_maint_pid);
++
++			if (au_ftest_lock(flags, FLUSH))
++				au_nwt_flush(&sbi->si_nowait);
++			si_noflush_read_lock(sb);
++		}
++	} else if (au_ftest_lock(flags, NOPLM)) {
++		AuDbg("ppid %d, pid %d\n", ppid, pid);
++		err = -EAGAIN;
++	}
++
++out:
++	return err;
++}
++
++void au_plink_maint_leave(struct au_sbinfo *sbinfo)
++{
++	spin_lock(&sbinfo->si_plink_maint_lock);
++	sbinfo->si_plink_maint_pid = 0;
++	spin_unlock(&sbinfo->si_plink_maint_lock);
++	wake_up_all(&sbinfo->si_plink_wq);
++}
++
++int au_plink_maint_enter(struct super_block *sb)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	/* make sure i am the only one in this fs */
++	si_write_lock(sb, AuLock_FLUSH);
++	if (au_opt_test(au_mntflags(sb), PLINK)) {
++		spin_lock(&sbinfo->si_plink_maint_lock);
++		if (!sbinfo->si_plink_maint_pid)
++			sbinfo->si_plink_maint_pid = current->pid;
++		else
++			err = -EBUSY;
++		spin_unlock(&sbinfo->si_plink_maint_lock);
++	}
++	si_write_unlock(sb);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_DEBUG
++void au_plink_list(struct super_block *sb)
++{
++	int i;
++	struct au_sbinfo *sbinfo;
++	struct hlist_head *plink_hlist;
++	struct pseudo_link *plink;
++
++	SiMustAnyLock(sb);
++
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
++	AuDebugOn(au_plink_maint(sb, AuLock_NOPLM));
++
++	for (i = 0; i < AuPlink_NHASH; i++) {
++		plink_hlist = &sbinfo->si_plink[i].head;
++		rcu_read_lock();
++		hlist_for_each_entry_rcu(plink, plink_hlist, hlist)
++			AuDbg("%lu\n", plink->inode->i_ino);
++		rcu_read_unlock();
++	}
++}
++#endif
++
++/* is the inode pseudo-linked? */
++int au_plink_test(struct inode *inode)
++{
++	int found, i;
++	struct au_sbinfo *sbinfo;
++	struct hlist_head *plink_hlist;
++	struct pseudo_link *plink;
++
++	sbinfo = au_sbi(inode->i_sb);
++	AuRwMustAnyLock(&sbinfo->si_rwsem);
++	AuDebugOn(!au_opt_test(au_mntflags(inode->i_sb), PLINK));
++	AuDebugOn(au_plink_maint(inode->i_sb, AuLock_NOPLM));
++
++	found = 0;
++	i = au_plink_hash(inode->i_ino);
++	plink_hlist = &sbinfo->si_plink[i].head;
++	rcu_read_lock();
++	hlist_for_each_entry_rcu(plink, plink_hlist, hlist)
++		if (plink->inode == inode) {
++			found = 1;
++			break;
++		}
++	rcu_read_unlock();
++	return found;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * generate a name for plink.
++ * the file will be stored under AUFS_WH_PLINKDIR.
++ */
++/* 20 is max digits length of ulong 64 */
++#define PLINK_NAME_LEN	((20 + 1) * 2)
++
++static int plink_name(char *name, int len, struct inode *inode,
++		      aufs_bindex_t bindex)
++{
++	int rlen;
++	struct inode *h_inode;
++
++	h_inode = au_h_iptr(inode, bindex);
++	rlen = snprintf(name, len, "%lu.%lu", inode->i_ino, h_inode->i_ino);
++	return rlen;
++}
++
++struct au_do_plink_lkup_args {
++	struct dentry **errp;
++	struct qstr *tgtname;
++	struct dentry *h_parent;
++	struct au_branch *br;
++};
++
++static struct dentry *au_do_plink_lkup(struct qstr *tgtname,
++				       struct dentry *h_parent,
++				       struct au_branch *br)
++{
++	struct dentry *h_dentry;
++	struct mutex *h_mtx;
++
++	h_mtx = &h_parent->d_inode->i_mutex;
++	mutex_lock_nested(h_mtx, AuLsc_I_CHILD2);
++	h_dentry = vfsub_lkup_one(tgtname, h_parent);
++	mutex_unlock(h_mtx);
++	return h_dentry;
++}
++
++static void au_call_do_plink_lkup(void *args)
++{
++	struct au_do_plink_lkup_args *a = args;
++	*a->errp = au_do_plink_lkup(a->tgtname, a->h_parent, a->br);
++}
++
++/* lookup the plink-ed @inode under the branch at @bindex */
++struct dentry *au_plink_lkup(struct inode *inode, aufs_bindex_t bindex)
++{
++	struct dentry *h_dentry, *h_parent;
++	struct au_branch *br;
++	struct inode *h_dir;
++	int wkq_err;
++	char a[PLINK_NAME_LEN];
++	struct qstr tgtname = QSTR_INIT(a, 0);
++
++	AuDebugOn(au_plink_maint(inode->i_sb, AuLock_NOPLM));
++
++	br = au_sbr(inode->i_sb, bindex);
++	h_parent = br->br_wbr->wbr_plink;
++	h_dir = h_parent->d_inode;
++	tgtname.len = plink_name(a, sizeof(a), inode, bindex);
++
++	if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) {
++		struct au_do_plink_lkup_args args = {
++			.errp		= &h_dentry,
++			.tgtname	= &tgtname,
++			.h_parent	= h_parent,
++			.br		= br
++		};
++
++		wkq_err = au_wkq_wait(au_call_do_plink_lkup, &args);
++		if (unlikely(wkq_err))
++			h_dentry = ERR_PTR(wkq_err);
++	} else
++		h_dentry = au_do_plink_lkup(&tgtname, h_parent, br);
++
++	return h_dentry;
++}
++
++/* create a pseudo-link */
++static int do_whplink(struct qstr *tgt, struct dentry *h_parent,
++		      struct dentry *h_dentry, struct au_branch *br)
++{
++	int err;
++	struct path h_path = {
++		.mnt = au_br_mnt(br)
++	};
++	struct inode *h_dir, *delegated;
++
++	h_dir = h_parent->d_inode;
++	mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
++again:
++	h_path.dentry = vfsub_lkup_one(tgt, h_parent);
++	err = PTR_ERR(h_path.dentry);
++	if (IS_ERR(h_path.dentry))
++		goto out;
++
++	err = 0;
++	/* wh.plink dir is not monitored */
++	/* todo: is it really safe? */
++	if (h_path.dentry->d_inode
++	    && h_path.dentry->d_inode != h_dentry->d_inode) {
++		delegated = NULL;
++		err = vfsub_unlink(h_dir, &h_path, &delegated, /*force*/0);
++		if (unlikely(err == -EWOULDBLOCK)) {
++			pr_warn("cannot retry for NFSv4 delegation"
++				" for an internal unlink\n");
++			iput(delegated);
++		}
++		dput(h_path.dentry);
++		h_path.dentry = NULL;
++		if (!err)
++			goto again;
++	}
++	if (!err && !h_path.dentry->d_inode) {
++		delegated = NULL;
++		err = vfsub_link(h_dentry, h_dir, &h_path, &delegated);
++		if (unlikely(err == -EWOULDBLOCK)) {
++			pr_warn("cannot retry for NFSv4 delegation"
++				" for an internal link\n");
++			iput(delegated);
++		}
++	}
++	dput(h_path.dentry);
++
++out:
++	mutex_unlock(&h_dir->i_mutex);
++	return err;
++}
++
++struct do_whplink_args {
++	int *errp;
++	struct qstr *tgt;
++	struct dentry *h_parent;
++	struct dentry *h_dentry;
++	struct au_branch *br;
++};
++
++static void call_do_whplink(void *args)
++{
++	struct do_whplink_args *a = args;
++	*a->errp = do_whplink(a->tgt, a->h_parent, a->h_dentry, a->br);
++}
++
++static int whplink(struct dentry *h_dentry, struct inode *inode,
++		   aufs_bindex_t bindex, struct au_branch *br)
++{
++	int err, wkq_err;
++	struct au_wbr *wbr;
++	struct dentry *h_parent;
++	struct inode *h_dir;
++	char a[PLINK_NAME_LEN];
++	struct qstr tgtname = QSTR_INIT(a, 0);
++
++	wbr = au_sbr(inode->i_sb, bindex)->br_wbr;
++	h_parent = wbr->wbr_plink;
++	h_dir = h_parent->d_inode;
++	tgtname.len = plink_name(a, sizeof(a), inode, bindex);
++
++	/* always superio. */
++	if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) {
++		struct do_whplink_args args = {
++			.errp		= &err,
++			.tgt		= &tgtname,
++			.h_parent	= h_parent,
++			.h_dentry	= h_dentry,
++			.br		= br
++		};
++		wkq_err = au_wkq_wait(call_do_whplink, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	} else
++		err = do_whplink(&tgtname, h_parent, h_dentry, br);
++
++	return err;
++}
++
++/* free a single plink */
++static void do_put_plink(struct pseudo_link *plink, int do_del)
++{
++	if (do_del)
++		hlist_del(&plink->hlist);
++	iput(plink->inode);
++	kfree(plink);
++}
++
++static void do_put_plink_rcu(struct rcu_head *rcu)
++{
++	struct pseudo_link *plink;
++
++	plink = container_of(rcu, struct pseudo_link, rcu);
++	iput(plink->inode);
++	kfree(plink);
++}
++
++/*
++ * create a new pseudo-link for @h_dentry on @bindex.
++ * the linked inode is held in aufs @inode.
++ */
++void au_plink_append(struct inode *inode, aufs_bindex_t bindex,
++		     struct dentry *h_dentry)
++{
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++	struct hlist_head *plink_hlist;
++	struct pseudo_link *plink, *tmp;
++	struct au_sphlhead *sphl;
++	int found, err, cnt, i;
++
++	sb = inode->i_sb;
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
++	AuDebugOn(au_plink_maint(sb, AuLock_NOPLM));
++
++	found = au_plink_test(inode);
++	if (found)
++		return;
++
++	i = au_plink_hash(inode->i_ino);
++	sphl = sbinfo->si_plink + i;
++	plink_hlist = &sphl->head;
++	tmp = kmalloc(sizeof(*plink), GFP_NOFS);
++	if (tmp)
++		tmp->inode = au_igrab(inode);
++	else {
++		err = -ENOMEM;
++		goto out;
++	}
++
++	spin_lock(&sphl->spin);
++	hlist_for_each_entry(plink, plink_hlist, hlist) {
++		if (plink->inode == inode) {
++			found = 1;
++			break;
++		}
++	}
++	if (!found)
++		hlist_add_head_rcu(&tmp->hlist, plink_hlist);
++	spin_unlock(&sphl->spin);
++	if (!found) {
++		cnt = au_sphl_count(sphl);
++#define msg "unexpectedly unblanced or too many pseudo-links"
++		if (cnt > AUFS_PLINK_WARN)
++			AuWarn1(msg ", %d\n", cnt);
++#undef msg
++		err = whplink(h_dentry, inode, bindex, au_sbr(sb, bindex));
++	} else {
++		do_put_plink(tmp, 0);
++		return;
++	}
++
++out:
++	if (unlikely(err)) {
++		pr_warn("err %d, damaged pseudo link.\n", err);
++		if (tmp) {
++			au_sphl_del_rcu(&tmp->hlist, sphl);
++			call_rcu(&tmp->rcu, do_put_plink_rcu);
++		}
++	}
++}
++
++/* free all plinks */
++void au_plink_put(struct super_block *sb, int verbose)
++{
++	int i, warned;
++	struct au_sbinfo *sbinfo;
++	struct hlist_head *plink_hlist;
++	struct hlist_node *tmp;
++	struct pseudo_link *plink;
++
++	SiMustWriteLock(sb);
++
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
++	AuDebugOn(au_plink_maint(sb, AuLock_NOPLM));
++
++	/* no spin_lock since sbinfo is write-locked */
++	warned = 0;
++	for (i = 0; i < AuPlink_NHASH; i++) {
++		plink_hlist = &sbinfo->si_plink[i].head;
++		if (!warned && verbose && !hlist_empty(plink_hlist)) {
++			pr_warn("pseudo-link is not flushed");
++			warned = 1;
++		}
++		hlist_for_each_entry_safe(plink, tmp, plink_hlist, hlist)
++			do_put_plink(plink, 0);
++		INIT_HLIST_HEAD(plink_hlist);
++	}
++}
++
++void au_plink_clean(struct super_block *sb, int verbose)
++{
++	struct dentry *root;
++
++	root = sb->s_root;
++	aufs_write_lock(root);
++	if (au_opt_test(au_mntflags(sb), PLINK))
++		au_plink_put(sb, verbose);
++	aufs_write_unlock(root);
++}
++
++static int au_plink_do_half_refresh(struct inode *inode, aufs_bindex_t br_id)
++{
++	int do_put;
++	aufs_bindex_t bstart, bend, bindex;
++
++	do_put = 0;
++	bstart = au_ibstart(inode);
++	bend = au_ibend(inode);
++	if (bstart >= 0) {
++		for (bindex = bstart; bindex <= bend; bindex++) {
++			if (!au_h_iptr(inode, bindex)
++			    || au_ii_br_id(inode, bindex) != br_id)
++				continue;
++			au_set_h_iptr(inode, bindex, NULL, 0);
++			do_put = 1;
++			break;
++		}
++		if (do_put)
++			for (bindex = bstart; bindex <= bend; bindex++)
++				if (au_h_iptr(inode, bindex)) {
++					do_put = 0;
++					break;
++				}
++	} else
++		do_put = 1;
++
++	return do_put;
++}
++
++/* free the plinks on a branch specified by @br_id */
++void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id)
++{
++	struct au_sbinfo *sbinfo;
++	struct hlist_head *plink_hlist;
++	struct hlist_node *tmp;
++	struct pseudo_link *plink;
++	struct inode *inode;
++	int i, do_put;
++
++	SiMustWriteLock(sb);
++
++	sbinfo = au_sbi(sb);
++	AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
++	AuDebugOn(au_plink_maint(sb, AuLock_NOPLM));
++
++	/* no spin_lock since sbinfo is write-locked */
++	for (i = 0; i < AuPlink_NHASH; i++) {
++		plink_hlist = &sbinfo->si_plink[i].head;
++		hlist_for_each_entry_safe(plink, tmp, plink_hlist, hlist) {
++			inode = au_igrab(plink->inode);
++			ii_write_lock_child(inode);
++			do_put = au_plink_do_half_refresh(inode, br_id);
++			if (do_put)
++				do_put_plink(plink, 1);
++			ii_write_unlock(inode);
++			iput(inode);
++		}
++	}
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/poll.c linux-4.0.4/fs/aufs/poll.c
+--- linux-4.0.4.orig/fs/aufs/poll.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/poll.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,42 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * poll operation
++ * There is only one filesystem which implements ->poll operation, currently.
++ */
++
++#include "aufs.h"
++
++unsigned int aufs_poll(struct file *file, poll_table *wait)
++{
++	unsigned int mask;
++	int err;
++	struct file *h_file;
++	struct dentry *dentry;
++	struct super_block *sb;
++
++	/* We should pretend an error happened. */
++	mask = POLLERR /* | POLLIN | POLLOUT */;
++	dentry = file->f_path.dentry;
++	sb = dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW);
++	err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0);
++	if (unlikely(err))
++		goto out;
++
++	/* it is not an error if h_file has no operation */
++	mask = DEFAULT_POLLMASK;
++	h_file = au_hf_top(file);
++	if (h_file->f_op->poll)
++		mask = h_file->f_op->poll(h_file, wait);
++
++	di_read_unlock(dentry, AuLock_IR);
++	fi_read_unlock(file);
++
++out:
++	si_read_unlock(sb);
++	AuTraceErr((int)mask);
++	return mask;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/posix_acl.c linux-4.0.4/fs/aufs/posix_acl.c
+--- linux-4.0.4.orig/fs/aufs/posix_acl.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/posix_acl.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,86 @@
++/*
++ * Copyright (C) 2014-2015 Junjiro R. Okajima
++ */
++
++/*
++ * posix acl operations
++ */
++
++#include <linux/fs.h>
++#include <linux/posix_acl.h>
++#include "aufs.h"
++
++struct posix_acl *aufs_get_acl(struct inode *inode, int type)
++{
++	struct posix_acl *acl;
++	int err;
++	aufs_bindex_t bindex;
++	struct inode *h_inode;
++	struct super_block *sb;
++
++	acl = NULL;
++	sb = inode->i_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	ii_read_lock_child(inode);
++	if (!(sb->s_flags & MS_POSIXACL))
++		goto out;
++
++	bindex = au_ibstart(inode);
++	h_inode = au_h_iptr(inode, bindex);
++	if (unlikely(!h_inode
++		     || ((h_inode->i_mode & S_IFMT)
++			 != (inode->i_mode & S_IFMT)))) {
++		err = au_busy_or_stale();
++		acl = ERR_PTR(err);
++		goto out;
++	}
++
++	/* always topmost only */
++	acl = get_acl(h_inode, type);
++
++out:
++	ii_read_unlock(inode);
++	si_read_unlock(sb);
++
++	AuTraceErrPtr(acl);
++	return acl;
++}
++
++int aufs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
++{
++	int err;
++	ssize_t ssz;
++	struct dentry *dentry;
++	struct au_srxattr arg = {
++		.type = AU_ACL_SET,
++		.u.acl_set = {
++			.acl	= acl,
++			.type	= type
++		},
++	};
++
++	mutex_lock(&inode->i_mutex);
++	if (inode->i_ino == AUFS_ROOT_INO)
++		dentry = dget(inode->i_sb->s_root);
++	else {
++		dentry = d_find_alias(inode);
++		if (!dentry)
++			dentry = d_find_any_alias(inode);
++		if (!dentry) {
++			pr_warn("cannot handle this inode, "
++				"please report to aufs-users ML\n");
++			err = -ENOENT;
++			goto out;
++		}
++	}
++
++	ssz = au_srxattr(dentry, &arg);
++	dput(dentry);
++	err = ssz;
++	if (ssz >= 0)
++		err = 0;
++
++out:
++	mutex_unlock(&inode->i_mutex);
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/procfs.c linux-4.0.4/fs/aufs/procfs.c
+--- linux-4.0.4.orig/fs/aufs/procfs.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/procfs.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,156 @@
++/*
++ * Copyright (C) 2010-2015 Junjiro R. Okajima
++ */
++
++/*
++ * procfs interfaces
++ */
++
++#include <linux/proc_fs.h>
++#include "aufs.h"
++
++static int au_procfs_plm_release(struct inode *inode, struct file *file)
++{
++	struct au_sbinfo *sbinfo;
++
++	sbinfo = file->private_data;
++	if (sbinfo) {
++		au_plink_maint_leave(sbinfo);
++		kobject_put(&sbinfo->si_kobj);
++	}
++
++	return 0;
++}
++
++static void au_procfs_plm_write_clean(struct file *file)
++{
++	struct au_sbinfo *sbinfo;
++
++	sbinfo = file->private_data;
++	if (sbinfo)
++		au_plink_clean(sbinfo->si_sb, /*verbose*/0);
++}
++
++static int au_procfs_plm_write_si(struct file *file, unsigned long id)
++{
++	int err;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++
++	err = -EBUSY;
++	if (unlikely(file->private_data))
++		goto out;
++
++	sb = NULL;
++	/* don't use au_sbilist_lock() here */
++	spin_lock(&au_sbilist.spin);
++	list_for_each_entry(sbinfo, &au_sbilist.head, si_list)
++		if (id == sysaufs_si_id(sbinfo)) {
++			kobject_get(&sbinfo->si_kobj);
++			sb = sbinfo->si_sb;
++			break;
++		}
++	spin_unlock(&au_sbilist.spin);
++
++	err = -EINVAL;
++	if (unlikely(!sb))
++		goto out;
++
++	err = au_plink_maint_enter(sb);
++	if (!err)
++		/* keep kobject_get() */
++		file->private_data = sbinfo;
++	else
++		kobject_put(&sbinfo->si_kobj);
++out:
++	return err;
++}
++
++/*
++ * Accept a valid "si=xxxx" only.
++ * Once it is accepted successfully, accept "clean" too.
++ */
++static ssize_t au_procfs_plm_write(struct file *file, const char __user *ubuf,
++				   size_t count, loff_t *ppos)
++{
++	ssize_t err;
++	unsigned long id;
++	/* last newline is allowed */
++	char buf[3 + sizeof(unsigned long) * 2 + 1];
++
++	err = -EACCES;
++	if (unlikely(!capable(CAP_SYS_ADMIN)))
++		goto out;
++
++	err = -EINVAL;
++	if (unlikely(count > sizeof(buf)))
++		goto out;
++
++	err = copy_from_user(buf, ubuf, count);
++	if (unlikely(err)) {
++		err = -EFAULT;
++		goto out;
++	}
++	buf[count] = 0;
++
++	err = -EINVAL;
++	if (!strcmp("clean", buf)) {
++		au_procfs_plm_write_clean(file);
++		goto out_success;
++	} else if (unlikely(strncmp("si=", buf, 3)))
++		goto out;
++
++	err = kstrtoul(buf + 3, 16, &id);
++	if (unlikely(err))
++		goto out;
++
++	err = au_procfs_plm_write_si(file, id);
++	if (unlikely(err))
++		goto out;
++
++out_success:
++	err = count; /* success */
++out:
++	return err;
++}
++
++static const struct file_operations au_procfs_plm_fop = {
++	.write		= au_procfs_plm_write,
++	.release	= au_procfs_plm_release,
++	.owner		= THIS_MODULE
++};
++
++/* ---------------------------------------------------------------------- */
++
++static struct proc_dir_entry *au_procfs_dir;
++
++void au_procfs_fin(void)
++{
++	remove_proc_entry(AUFS_PLINK_MAINT_NAME, au_procfs_dir);
++	remove_proc_entry(AUFS_PLINK_MAINT_DIR, NULL);
++}
++
++int __init au_procfs_init(void)
++{
++	int err;
++	struct proc_dir_entry *entry;
++
++	err = -ENOMEM;
++	au_procfs_dir = proc_mkdir(AUFS_PLINK_MAINT_DIR, NULL);
++	if (unlikely(!au_procfs_dir))
++		goto out;
++
++	entry = proc_create(AUFS_PLINK_MAINT_NAME, S_IFREG | S_IWUSR,
++			    au_procfs_dir, &au_procfs_plm_fop);
++	if (unlikely(!entry))
++		goto out_dir;
++
++	err = 0;
++	goto out; /* success */
++
++
++out_dir:
++	remove_proc_entry(AUFS_PLINK_MAINT_DIR, NULL);
++out:
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/rdu.c linux-4.0.4/fs/aufs/rdu.c
+--- linux-4.0.4.orig/fs/aufs/rdu.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/rdu.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,375 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * readdir in userspace.
++ */
++
++#include <linux/compat.h>
++#include <linux/fs_stack.h>
++#include <linux/security.h>
++#include "aufs.h"
++
++/* bits for struct aufs_rdu.flags */
++#define	AuRdu_CALLED	1
++#define	AuRdu_CONT	(1 << 1)
++#define	AuRdu_FULL	(1 << 2)
++#define au_ftest_rdu(flags, name)	((flags) & AuRdu_##name)
++#define au_fset_rdu(flags, name) \
++	do { (flags) |= AuRdu_##name; } while (0)
++#define au_fclr_rdu(flags, name) \
++	do { (flags) &= ~AuRdu_##name; } while (0)
++
++struct au_rdu_arg {
++	struct dir_context		ctx;
++	struct aufs_rdu			*rdu;
++	union au_rdu_ent_ul		ent;
++	unsigned long			end;
++
++	struct super_block		*sb;
++	int				err;
++};
++
++static int au_rdu_fill(struct dir_context *ctx, const char *name, int nlen,
++		       loff_t offset, u64 h_ino, unsigned int d_type)
++{
++	int err, len;
++	struct au_rdu_arg *arg = container_of(ctx, struct au_rdu_arg, ctx);
++	struct aufs_rdu *rdu = arg->rdu;
++	struct au_rdu_ent ent;
++
++	err = 0;
++	arg->err = 0;
++	au_fset_rdu(rdu->cookie.flags, CALLED);
++	len = au_rdu_len(nlen);
++	if (arg->ent.ul + len  < arg->end) {
++		ent.ino = h_ino;
++		ent.bindex = rdu->cookie.bindex;
++		ent.type = d_type;
++		ent.nlen = nlen;
++		if (unlikely(nlen > AUFS_MAX_NAMELEN))
++			ent.type = DT_UNKNOWN;
++
++		/* unnecessary to support mmap_sem since this is a dir */
++		err = -EFAULT;
++		if (copy_to_user(arg->ent.e, &ent, sizeof(ent)))
++			goto out;
++		if (copy_to_user(arg->ent.e->name, name, nlen))
++			goto out;
++		/* the terminating NULL */
++		if (__put_user(0, arg->ent.e->name + nlen))
++			goto out;
++		err = 0;
++		/* AuDbg("%p, %.*s\n", arg->ent.p, nlen, name); */
++		arg->ent.ul += len;
++		rdu->rent++;
++	} else {
++		err = -EFAULT;
++		au_fset_rdu(rdu->cookie.flags, FULL);
++		rdu->full = 1;
++		rdu->tail = arg->ent;
++	}
++
++out:
++	/* AuTraceErr(err); */
++	return err;
++}
++
++static int au_rdu_do(struct file *h_file, struct au_rdu_arg *arg)
++{
++	int err;
++	loff_t offset;
++	struct au_rdu_cookie *cookie = &arg->rdu->cookie;
++
++	/* we don't have to care (FMODE_32BITHASH | FMODE_64BITHASH) for ext4 */
++	offset = vfsub_llseek(h_file, cookie->h_pos, SEEK_SET);
++	err = offset;
++	if (unlikely(offset != cookie->h_pos))
++		goto out;
++
++	err = 0;
++	do {
++		arg->err = 0;
++		au_fclr_rdu(cookie->flags, CALLED);
++		/* smp_mb(); */
++		err = vfsub_iterate_dir(h_file, &arg->ctx);
++		if (err >= 0)
++			err = arg->err;
++	} while (!err
++		 && au_ftest_rdu(cookie->flags, CALLED)
++		 && !au_ftest_rdu(cookie->flags, FULL));
++	cookie->h_pos = h_file->f_pos;
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int au_rdu(struct file *file, struct aufs_rdu *rdu)
++{
++	int err;
++	aufs_bindex_t bend;
++	struct au_rdu_arg arg = {
++		.ctx = {
++			.actor = au_rdu_fill
++		}
++	};
++	struct dentry *dentry;
++	struct inode *inode;
++	struct file *h_file;
++	struct au_rdu_cookie *cookie = &rdu->cookie;
++
++	err = !access_ok(VERIFY_WRITE, rdu->ent.e, rdu->sz);
++	if (unlikely(err)) {
++		err = -EFAULT;
++		AuTraceErr(err);
++		goto out;
++	}
++	rdu->rent = 0;
++	rdu->tail = rdu->ent;
++	rdu->full = 0;
++	arg.rdu = rdu;
++	arg.ent = rdu->ent;
++	arg.end = arg.ent.ul;
++	arg.end += rdu->sz;
++
++	err = -ENOTDIR;
++	if (unlikely(!file->f_op->iterate))
++		goto out;
++
++	err = security_file_permission(file, MAY_READ);
++	AuTraceErr(err);
++	if (unlikely(err))
++		goto out;
++
++	dentry = file->f_path.dentry;
++	inode = dentry->d_inode;
++#if 1
++	mutex_lock(&inode->i_mutex);
++#else
++	err = mutex_lock_killable(&inode->i_mutex);
++	AuTraceErr(err);
++	if (unlikely(err))
++		goto out;
++#endif
++
++	arg.sb = inode->i_sb;
++	err = si_read_lock(arg.sb, AuLock_FLUSH | AuLock_NOPLM);
++	if (unlikely(err))
++		goto out_mtx;
++	err = au_alive_dir(dentry);
++	if (unlikely(err))
++		goto out_si;
++	/* todo: reval? */
++	fi_read_lock(file);
++
++	err = -EAGAIN;
++	if (unlikely(au_ftest_rdu(cookie->flags, CONT)
++		     && cookie->generation != au_figen(file)))
++		goto out_unlock;
++
++	err = 0;
++	if (!rdu->blk) {
++		rdu->blk = au_sbi(arg.sb)->si_rdblk;
++		if (!rdu->blk)
++			rdu->blk = au_dir_size(file, /*dentry*/NULL);
++	}
++	bend = au_fbstart(file);
++	if (cookie->bindex < bend)
++		cookie->bindex = bend;
++	bend = au_fbend_dir(file);
++	/* AuDbg("b%d, b%d\n", cookie->bindex, bend); */
++	for (; !err && cookie->bindex <= bend;
++	     cookie->bindex++, cookie->h_pos = 0) {
++		h_file = au_hf_dir(file, cookie->bindex);
++		if (!h_file)
++			continue;
++
++		au_fclr_rdu(cookie->flags, FULL);
++		err = au_rdu_do(h_file, &arg);
++		AuTraceErr(err);
++		if (unlikely(au_ftest_rdu(cookie->flags, FULL) || err))
++			break;
++	}
++	AuDbg("rent %llu\n", rdu->rent);
++
++	if (!err && !au_ftest_rdu(cookie->flags, CONT)) {
++		rdu->shwh = !!au_opt_test(au_sbi(arg.sb)->si_mntflags, SHWH);
++		au_fset_rdu(cookie->flags, CONT);
++		cookie->generation = au_figen(file);
++	}
++
++	ii_read_lock_child(inode);
++	fsstack_copy_attr_atime(inode, au_h_iptr(inode, au_ibstart(inode)));
++	ii_read_unlock(inode);
++
++out_unlock:
++	fi_read_unlock(file);
++out_si:
++	si_read_unlock(arg.sb);
++out_mtx:
++	mutex_unlock(&inode->i_mutex);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++static int au_rdu_ino(struct file *file, struct aufs_rdu *rdu)
++{
++	int err;
++	ino_t ino;
++	unsigned long long nent;
++	union au_rdu_ent_ul *u;
++	struct au_rdu_ent ent;
++	struct super_block *sb;
++
++	err = 0;
++	nent = rdu->nent;
++	u = &rdu->ent;
++	sb = file->f_path.dentry->d_sb;
++	si_read_lock(sb, AuLock_FLUSH);
++	while (nent-- > 0) {
++		/* unnecessary to support mmap_sem since this is a dir */
++		err = copy_from_user(&ent, u->e, sizeof(ent));
++		if (!err)
++			err = !access_ok(VERIFY_WRITE, &u->e->ino, sizeof(ino));
++		if (unlikely(err)) {
++			err = -EFAULT;
++			AuTraceErr(err);
++			break;
++		}
++
++		/* AuDbg("b%d, i%llu\n", ent.bindex, ent.ino); */
++		if (!ent.wh)
++			err = au_ino(sb, ent.bindex, ent.ino, ent.type, &ino);
++		else
++			err = au_wh_ino(sb, ent.bindex, ent.ino, ent.type,
++					&ino);
++		if (unlikely(err)) {
++			AuTraceErr(err);
++			break;
++		}
++
++		err = __put_user(ino, &u->e->ino);
++		if (unlikely(err)) {
++			err = -EFAULT;
++			AuTraceErr(err);
++			break;
++		}
++		u->ul += au_rdu_len(ent.nlen);
++	}
++	si_read_unlock(sb);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_rdu_verify(struct aufs_rdu *rdu)
++{
++	AuDbg("rdu{%llu, %p, %u | %u | %llu, %u, %u | "
++	      "%llu, b%d, 0x%x, g%u}\n",
++	      rdu->sz, rdu->ent.e, rdu->verify[AufsCtlRduV_SZ],
++	      rdu->blk,
++	      rdu->rent, rdu->shwh, rdu->full,
++	      rdu->cookie.h_pos, rdu->cookie.bindex, rdu->cookie.flags,
++	      rdu->cookie.generation);
++
++	if (rdu->verify[AufsCtlRduV_SZ] == sizeof(*rdu))
++		return 0;
++
++	AuDbg("%u:%u\n",
++	      rdu->verify[AufsCtlRduV_SZ], (unsigned int)sizeof(*rdu));
++	return -EINVAL;
++}
++
++long au_rdu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
++{
++	long err, e;
++	struct aufs_rdu rdu;
++	void __user *p = (void __user *)arg;
++
++	err = copy_from_user(&rdu, p, sizeof(rdu));
++	if (unlikely(err)) {
++		err = -EFAULT;
++		AuTraceErr(err);
++		goto out;
++	}
++	err = au_rdu_verify(&rdu);
++	if (unlikely(err))
++		goto out;
++
++	switch (cmd) {
++	case AUFS_CTL_RDU:
++		err = au_rdu(file, &rdu);
++		if (unlikely(err))
++			break;
++
++		e = copy_to_user(p, &rdu, sizeof(rdu));
++		if (unlikely(e)) {
++			err = -EFAULT;
++			AuTraceErr(err);
++		}
++		break;
++	case AUFS_CTL_RDU_INO:
++		err = au_rdu_ino(file, &rdu);
++		break;
++
++	default:
++		/* err = -ENOTTY; */
++		err = -EINVAL;
++	}
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++#ifdef CONFIG_COMPAT
++long au_rdu_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
++{
++	long err, e;
++	struct aufs_rdu rdu;
++	void __user *p = compat_ptr(arg);
++
++	/* todo: get_user()? */
++	err = copy_from_user(&rdu, p, sizeof(rdu));
++	if (unlikely(err)) {
++		err = -EFAULT;
++		AuTraceErr(err);
++		goto out;
++	}
++	rdu.ent.e = compat_ptr(rdu.ent.ul);
++	err = au_rdu_verify(&rdu);
++	if (unlikely(err))
++		goto out;
++
++	switch (cmd) {
++	case AUFS_CTL_RDU:
++		err = au_rdu(file, &rdu);
++		if (unlikely(err))
++			break;
++
++		rdu.ent.ul = ptr_to_compat(rdu.ent.e);
++		rdu.tail.ul = ptr_to_compat(rdu.tail.e);
++		e = copy_to_user(p, &rdu, sizeof(rdu));
++		if (unlikely(e)) {
++			err = -EFAULT;
++			AuTraceErr(err);
++		}
++		break;
++	case AUFS_CTL_RDU_INO:
++		err = au_rdu_ino(file, &rdu);
++		break;
++
++	default:
++		/* err = -ENOTTY; */
++		err = -EINVAL;
++	}
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++#endif
+diff -Nur linux-4.0.4.orig/fs/aufs/rwsem.h linux-4.0.4/fs/aufs/rwsem.h
+--- linux-4.0.4.orig/fs/aufs/rwsem.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/rwsem.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,178 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * simple read-write semaphore wrappers
++ */
++
++#ifndef __AUFS_RWSEM_H__
++#define __AUFS_RWSEM_H__
++
++#ifdef __KERNEL__
++
++#include "debug.h"
++
++struct au_rwsem {
++	struct rw_semaphore	rwsem;
++#ifdef CONFIG_AUFS_DEBUG
++	/* just for debugging, not almighty counter */
++	atomic_t		rcnt, wcnt;
++#endif
++};
++
++#ifdef CONFIG_AUFS_DEBUG
++#define AuDbgCntInit(rw) do { \
++	atomic_set(&(rw)->rcnt, 0); \
++	atomic_set(&(rw)->wcnt, 0); \
++	smp_mb(); /* atomic set */ \
++} while (0)
++
++#define AuDbgRcntInc(rw)	atomic_inc(&(rw)->rcnt)
++#define AuDbgRcntDec(rw)	WARN_ON(atomic_dec_return(&(rw)->rcnt) < 0)
++#define AuDbgWcntInc(rw)	atomic_inc(&(rw)->wcnt)
++#define AuDbgWcntDec(rw)	WARN_ON(atomic_dec_return(&(rw)->wcnt) < 0)
++#else
++#define AuDbgCntInit(rw)	do {} while (0)
++#define AuDbgRcntInc(rw)	do {} while (0)
++#define AuDbgRcntDec(rw)	do {} while (0)
++#define AuDbgWcntInc(rw)	do {} while (0)
++#define AuDbgWcntDec(rw)	do {} while (0)
++#endif /* CONFIG_AUFS_DEBUG */
++
++/* to debug easier, do not make them inlined functions */
++#define AuRwMustNoWaiters(rw)	AuDebugOn(!list_empty(&(rw)->rwsem.wait_list))
++/* rwsem_is_locked() is unusable */
++#define AuRwMustReadLock(rw)	AuDebugOn(atomic_read(&(rw)->rcnt) <= 0)
++#define AuRwMustWriteLock(rw)	AuDebugOn(atomic_read(&(rw)->wcnt) <= 0)
++#define AuRwMustAnyLock(rw)	AuDebugOn(atomic_read(&(rw)->rcnt) <= 0 \
++					&& atomic_read(&(rw)->wcnt) <= 0)
++#define AuRwDestroy(rw)		AuDebugOn(atomic_read(&(rw)->rcnt) \
++					|| atomic_read(&(rw)->wcnt))
++
++#define au_rw_class(rw, key)	lockdep_set_class(&(rw)->rwsem, key)
++
++static inline void au_rw_init(struct au_rwsem *rw)
++{
++	AuDbgCntInit(rw);
++	init_rwsem(&rw->rwsem);
++}
++
++static inline void au_rw_init_wlock(struct au_rwsem *rw)
++{
++	au_rw_init(rw);
++	down_write(&rw->rwsem);
++	AuDbgWcntInc(rw);
++}
++
++static inline void au_rw_init_wlock_nested(struct au_rwsem *rw,
++					   unsigned int lsc)
++{
++	au_rw_init(rw);
++	down_write_nested(&rw->rwsem, lsc);
++	AuDbgWcntInc(rw);
++}
++
++static inline void au_rw_read_lock(struct au_rwsem *rw)
++{
++	down_read(&rw->rwsem);
++	AuDbgRcntInc(rw);
++}
++
++static inline void au_rw_read_lock_nested(struct au_rwsem *rw, unsigned int lsc)
++{
++	down_read_nested(&rw->rwsem, lsc);
++	AuDbgRcntInc(rw);
++}
++
++static inline void au_rw_read_unlock(struct au_rwsem *rw)
++{
++	AuRwMustReadLock(rw);
++	AuDbgRcntDec(rw);
++	up_read(&rw->rwsem);
++}
++
++static inline void au_rw_dgrade_lock(struct au_rwsem *rw)
++{
++	AuRwMustWriteLock(rw);
++	AuDbgRcntInc(rw);
++	AuDbgWcntDec(rw);
++	downgrade_write(&rw->rwsem);
++}
++
++static inline void au_rw_write_lock(struct au_rwsem *rw)
++{
++	down_write(&rw->rwsem);
++	AuDbgWcntInc(rw);
++}
++
++static inline void au_rw_write_lock_nested(struct au_rwsem *rw,
++					   unsigned int lsc)
++{
++	down_write_nested(&rw->rwsem, lsc);
++	AuDbgWcntInc(rw);
++}
++
++static inline void au_rw_write_unlock(struct au_rwsem *rw)
++{
++	AuRwMustWriteLock(rw);
++	AuDbgWcntDec(rw);
++	up_write(&rw->rwsem);
++}
++
++/* why is not _nested version defined */
++static inline int au_rw_read_trylock(struct au_rwsem *rw)
++{
++	int ret;
++
++	ret = down_read_trylock(&rw->rwsem);
++	if (ret)
++		AuDbgRcntInc(rw);
++	return ret;
++}
++
++static inline int au_rw_write_trylock(struct au_rwsem *rw)
++{
++	int ret;
++
++	ret = down_write_trylock(&rw->rwsem);
++	if (ret)
++		AuDbgWcntInc(rw);
++	return ret;
++}
++
++#undef AuDbgCntInit
++#undef AuDbgRcntInc
++#undef AuDbgRcntDec
++#undef AuDbgWcntInc
++#undef AuDbgWcntDec
++
++#define AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
++static inline void prefix##_read_lock(param) \
++{ au_rw_read_lock(rwsem); } \
++static inline void prefix##_write_lock(param) \
++{ au_rw_write_lock(rwsem); } \
++static inline int prefix##_read_trylock(param) \
++{ return au_rw_read_trylock(rwsem); } \
++static inline int prefix##_write_trylock(param) \
++{ return au_rw_write_trylock(rwsem); }
++/* why is not _nested version defined */
++/* static inline void prefix##_read_trylock_nested(param, lsc)
++{ au_rw_read_trylock_nested(rwsem, lsc)); }
++static inline void prefix##_write_trylock_nestd(param, lsc)
++{ au_rw_write_trylock_nested(rwsem, lsc); } */
++
++#define AuSimpleUnlockRwsemFuncs(prefix, param, rwsem) \
++static inline void prefix##_read_unlock(param) \
++{ au_rw_read_unlock(rwsem); } \
++static inline void prefix##_write_unlock(param) \
++{ au_rw_write_unlock(rwsem); } \
++static inline void prefix##_downgrade_lock(param) \
++{ au_rw_dgrade_lock(rwsem); }
++
++#define AuSimpleRwsemFuncs(prefix, param, rwsem) \
++	AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
++	AuSimpleUnlockRwsemFuncs(prefix, param, rwsem)
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_RWSEM_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/sbinfo.c linux-4.0.4/fs/aufs/sbinfo.c
+--- linux-4.0.4.orig/fs/aufs/sbinfo.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/sbinfo.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,341 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * superblock private data
++ */
++
++#include "aufs.h"
++
++/*
++ * they are necessary regardless sysfs is disabled.
++ */
++void au_si_free(struct kobject *kobj)
++{
++	int i;
++	struct au_sbinfo *sbinfo;
++	char *locked __maybe_unused; /* debug only */
++
++	sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
++	for (i = 0; i < AuPlink_NHASH; i++)
++		AuDebugOn(!hlist_empty(&sbinfo->si_plink[i].head));
++	AuDebugOn(atomic_read(&sbinfo->si_nowait.nw_len));
++
++	au_rw_write_lock(&sbinfo->si_rwsem);
++	au_br_free(sbinfo);
++	au_rw_write_unlock(&sbinfo->si_rwsem);
++
++	AuDebugOn(radix_tree_gang_lookup
++		  (&sbinfo->au_si_pid.tree, (void **)&locked,
++		   /*first_index*/PID_MAX_DEFAULT - 1,
++		   /*max_items*/sizeof(locked)/sizeof(*locked)));
++
++	kfree(sbinfo->si_branch);
++	kfree(sbinfo->au_si_pid.bitmap);
++	mutex_destroy(&sbinfo->si_xib_mtx);
++	AuRwDestroy(&sbinfo->si_rwsem);
++
++	kfree(sbinfo);
++}
++
++int au_si_alloc(struct super_block *sb)
++{
++	int err, i;
++	struct au_sbinfo *sbinfo;
++	static struct lock_class_key aufs_si;
++
++	err = -ENOMEM;
++	sbinfo = kzalloc(sizeof(*sbinfo), GFP_NOFS);
++	if (unlikely(!sbinfo))
++		goto out;
++
++	BUILD_BUG_ON(sizeof(unsigned long) !=
++		     sizeof(*sbinfo->au_si_pid.bitmap));
++	sbinfo->au_si_pid.bitmap = kcalloc(BITS_TO_LONGS(PID_MAX_DEFAULT),
++					sizeof(*sbinfo->au_si_pid.bitmap),
++					GFP_NOFS);
++	if (unlikely(!sbinfo->au_si_pid.bitmap))
++		goto out_sbinfo;
++
++	/* will be reallocated separately */
++	sbinfo->si_branch = kzalloc(sizeof(*sbinfo->si_branch), GFP_NOFS);
++	if (unlikely(!sbinfo->si_branch))
++		goto out_pidmap;
++
++	err = sysaufs_si_init(sbinfo);
++	if (unlikely(err))
++		goto out_br;
++
++	au_nwt_init(&sbinfo->si_nowait);
++	au_rw_init_wlock(&sbinfo->si_rwsem);
++	au_rw_class(&sbinfo->si_rwsem, &aufs_si);
++	spin_lock_init(&sbinfo->au_si_pid.tree_lock);
++	INIT_RADIX_TREE(&sbinfo->au_si_pid.tree, GFP_ATOMIC | __GFP_NOFAIL);
++
++	atomic_long_set(&sbinfo->si_ninodes, 0);
++	atomic_long_set(&sbinfo->si_nfiles, 0);
++
++	sbinfo->si_bend = -1;
++	sbinfo->si_last_br_id = AUFS_BRANCH_MAX / 2;
++
++	sbinfo->si_wbr_copyup = AuWbrCopyup_Def;
++	sbinfo->si_wbr_create = AuWbrCreate_Def;
++	sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + sbinfo->si_wbr_copyup;
++	sbinfo->si_wbr_create_ops = au_wbr_create_ops + sbinfo->si_wbr_create;
++
++	au_fhsm_init(sbinfo);
++
++	sbinfo->si_mntflags = au_opts_plink(AuOpt_Def);
++
++	sbinfo->si_xino_jiffy = jiffies;
++	sbinfo->si_xino_expire
++		= msecs_to_jiffies(AUFS_XINO_DEF_SEC * MSEC_PER_SEC);
++	mutex_init(&sbinfo->si_xib_mtx);
++	sbinfo->si_xino_brid = -1;
++	/* leave si_xib_last_pindex and si_xib_next_bit */
++
++	au_sphl_init(&sbinfo->si_aopen);
++
++	sbinfo->si_rdcache = msecs_to_jiffies(AUFS_RDCACHE_DEF * MSEC_PER_SEC);
++	sbinfo->si_rdblk = AUFS_RDBLK_DEF;
++	sbinfo->si_rdhash = AUFS_RDHASH_DEF;
++	sbinfo->si_dirwh = AUFS_DIRWH_DEF;
++
++	for (i = 0; i < AuPlink_NHASH; i++)
++		au_sphl_init(sbinfo->si_plink + i);
++	init_waitqueue_head(&sbinfo->si_plink_wq);
++	spin_lock_init(&sbinfo->si_plink_maint_lock);
++
++	au_sphl_init(&sbinfo->si_files);
++
++	/* leave other members for sysaufs and si_mnt. */
++	sbinfo->si_sb = sb;
++	sb->s_fs_info = sbinfo;
++	si_pid_set(sb);
++	return 0; /* success */
++
++out_br:
++	kfree(sbinfo->si_branch);
++out_pidmap:
++	kfree(sbinfo->au_si_pid.bitmap);
++out_sbinfo:
++	kfree(sbinfo);
++out:
++	return err;
++}
++
++int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr)
++{
++	int err, sz;
++	struct au_branch **brp;
++
++	AuRwMustWriteLock(&sbinfo->si_rwsem);
++
++	err = -ENOMEM;
++	sz = sizeof(*brp) * (sbinfo->si_bend + 1);
++	if (unlikely(!sz))
++		sz = sizeof(*brp);
++	brp = au_kzrealloc(sbinfo->si_branch, sz, sizeof(*brp) * nbr, GFP_NOFS);
++	if (brp) {
++		sbinfo->si_branch = brp;
++		err = 0;
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++unsigned int au_sigen_inc(struct super_block *sb)
++{
++	unsigned int gen;
++
++	SiMustWriteLock(sb);
++
++	gen = ++au_sbi(sb)->si_generation;
++	au_update_digen(sb->s_root);
++	au_update_iigen(sb->s_root->d_inode, /*half*/0);
++	sb->s_root->d_inode->i_version++;
++	return gen;
++}
++
++aufs_bindex_t au_new_br_id(struct super_block *sb)
++{
++	aufs_bindex_t br_id;
++	int i;
++	struct au_sbinfo *sbinfo;
++
++	SiMustWriteLock(sb);
++
++	sbinfo = au_sbi(sb);
++	for (i = 0; i <= AUFS_BRANCH_MAX; i++) {
++		br_id = ++sbinfo->si_last_br_id;
++		AuDebugOn(br_id < 0);
++		if (br_id && au_br_index(sb, br_id) < 0)
++			return br_id;
++	}
++
++	return -1;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* it is ok that new 'nwt' tasks are appended while we are sleeping */
++int si_read_lock(struct super_block *sb, int flags)
++{
++	int err;
++
++	err = 0;
++	if (au_ftest_lock(flags, FLUSH))
++		au_nwt_flush(&au_sbi(sb)->si_nowait);
++
++	si_noflush_read_lock(sb);
++	err = au_plink_maint(sb, flags);
++	if (unlikely(err))
++		si_read_unlock(sb);
++
++	return err;
++}
++
++int si_write_lock(struct super_block *sb, int flags)
++{
++	int err;
++
++	if (au_ftest_lock(flags, FLUSH))
++		au_nwt_flush(&au_sbi(sb)->si_nowait);
++
++	si_noflush_write_lock(sb);
++	err = au_plink_maint(sb, flags);
++	if (unlikely(err))
++		si_write_unlock(sb);
++
++	return err;
++}
++
++/* dentry and super_block lock. call at entry point */
++int aufs_read_lock(struct dentry *dentry, int flags)
++{
++	int err;
++	struct super_block *sb;
++
++	sb = dentry->d_sb;
++	err = si_read_lock(sb, flags);
++	if (unlikely(err))
++		goto out;
++
++	if (au_ftest_lock(flags, DW))
++		di_write_lock_child(dentry);
++	else
++		di_read_lock_child(dentry, flags);
++
++	if (au_ftest_lock(flags, GEN)) {
++		err = au_digen_test(dentry, au_sigen(sb));
++		AuDebugOn(!err && au_dbrange_test(dentry));
++		if (unlikely(err))
++			aufs_read_unlock(dentry, flags);
++	}
++
++out:
++	return err;
++}
++
++void aufs_read_unlock(struct dentry *dentry, int flags)
++{
++	if (au_ftest_lock(flags, DW))
++		di_write_unlock(dentry);
++	else
++		di_read_unlock(dentry, flags);
++	si_read_unlock(dentry->d_sb);
++}
++
++void aufs_write_lock(struct dentry *dentry)
++{
++	si_write_lock(dentry->d_sb, AuLock_FLUSH | AuLock_NOPLMW);
++	di_write_lock_child(dentry);
++}
++
++void aufs_write_unlock(struct dentry *dentry)
++{
++	di_write_unlock(dentry);
++	si_write_unlock(dentry->d_sb);
++}
++
++int aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags)
++{
++	int err;
++	unsigned int sigen;
++	struct super_block *sb;
++
++	sb = d1->d_sb;
++	err = si_read_lock(sb, flags);
++	if (unlikely(err))
++		goto out;
++
++	di_write_lock2_child(d1, d2, au_ftest_lock(flags, DIR));
++
++	if (au_ftest_lock(flags, GEN)) {
++		sigen = au_sigen(sb);
++		err = au_digen_test(d1, sigen);
++		AuDebugOn(!err && au_dbrange_test(d1));
++		if (!err) {
++			err = au_digen_test(d2, sigen);
++			AuDebugOn(!err && au_dbrange_test(d2));
++		}
++		if (unlikely(err))
++			aufs_read_and_write_unlock2(d1, d2);
++	}
++
++out:
++	return err;
++}
++
++void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2)
++{
++	di_write_unlock2(d1, d2);
++	si_read_unlock(d1->d_sb);
++}
++
++/* ---------------------------------------------------------------------- */
++
++int si_pid_test_slow(struct super_block *sb)
++{
++	void *p;
++
++	rcu_read_lock();
++	p = radix_tree_lookup(&au_sbi(sb)->au_si_pid.tree, current->pid);
++	rcu_read_unlock();
++
++	return (long)!!p;
++}
++
++void si_pid_set_slow(struct super_block *sb)
++{
++	int err;
++	struct au_sbinfo *sbinfo;
++
++	AuDebugOn(si_pid_test_slow(sb));
++
++	sbinfo = au_sbi(sb);
++	err = radix_tree_preload(GFP_NOFS | __GFP_NOFAIL);
++	AuDebugOn(err);
++	spin_lock(&sbinfo->au_si_pid.tree_lock);
++	err = radix_tree_insert(&sbinfo->au_si_pid.tree, current->pid,
++				/*any valid ptr*/sb);
++	spin_unlock(&sbinfo->au_si_pid.tree_lock);
++	AuDebugOn(err);
++	radix_tree_preload_end();
++}
++
++void si_pid_clr_slow(struct super_block *sb)
++{
++	void *p;
++	struct au_sbinfo *sbinfo;
++
++	AuDebugOn(!si_pid_test_slow(sb));
++
++	sbinfo = au_sbi(sb);
++	spin_lock(&sbinfo->au_si_pid.tree_lock);
++	p = radix_tree_delete(&sbinfo->au_si_pid.tree, current->pid);
++	spin_unlock(&sbinfo->au_si_pid.tree_lock);
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/spl.h linux-4.0.4/fs/aufs/spl.h
+--- linux-4.0.4.orig/fs/aufs/spl.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/spl.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,98 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * simple list protected by a spinlock
++ */
++
++#ifndef __AUFS_SPL_H__
++#define __AUFS_SPL_H__
++
++#ifdef __KERNEL__
++
++struct au_splhead {
++	spinlock_t		spin;
++	struct list_head	head;
++};
++
++static inline void au_spl_init(struct au_splhead *spl)
++{
++	spin_lock_init(&spl->spin);
++	INIT_LIST_HEAD(&spl->head);
++}
++
++static inline void au_spl_add(struct list_head *list, struct au_splhead *spl)
++{
++	spin_lock(&spl->spin);
++	list_add(list, &spl->head);
++	spin_unlock(&spl->spin);
++}
++
++static inline void au_spl_del(struct list_head *list, struct au_splhead *spl)
++{
++	spin_lock(&spl->spin);
++	list_del(list);
++	spin_unlock(&spl->spin);
++}
++
++static inline void au_spl_del_rcu(struct list_head *list,
++				  struct au_splhead *spl)
++{
++	spin_lock(&spl->spin);
++	list_del_rcu(list);
++	spin_unlock(&spl->spin);
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_sphlhead {
++	spinlock_t		spin;
++	struct hlist_head	head;
++};
++
++static inline void au_sphl_init(struct au_sphlhead *sphl)
++{
++	spin_lock_init(&sphl->spin);
++	INIT_HLIST_HEAD(&sphl->head);
++}
++
++static inline void au_sphl_add(struct hlist_node *hlist,
++			       struct au_sphlhead *sphl)
++{
++	spin_lock(&sphl->spin);
++	hlist_add_head(hlist, &sphl->head);
++	spin_unlock(&sphl->spin);
++}
++
++static inline void au_sphl_del(struct hlist_node *hlist,
++			       struct au_sphlhead *sphl)
++{
++	spin_lock(&sphl->spin);
++	hlist_del(hlist);
++	spin_unlock(&sphl->spin);
++}
++
++static inline void au_sphl_del_rcu(struct hlist_node *hlist,
++				   struct au_sphlhead *sphl)
++{
++	spin_lock(&sphl->spin);
++	hlist_del_rcu(hlist);
++	spin_unlock(&sphl->spin);
++}
++
++static inline unsigned long au_sphl_count(struct au_sphlhead *sphl)
++{
++	unsigned long cnt;
++	struct hlist_node *pos;
++
++	cnt = 0;
++	spin_lock(&sphl->spin);
++	hlist_for_each(pos, &sphl->head)
++		cnt++;
++	spin_unlock(&sphl->spin);
++	return cnt;
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_SPL_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/super.c linux-4.0.4/fs/aufs/super.c
+--- linux-4.0.4.orig/fs/aufs/super.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/super.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,993 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * mount and super_block operations
++ */
++
++#include <linux/mm.h>
++#include <linux/seq_file.h>
++#include <linux/statfs.h>
++#include <linux/vmalloc.h>
++#include "aufs.h"
++
++/*
++ * super_operations
++ */
++static struct inode *aufs_alloc_inode(struct super_block *sb __maybe_unused)
++{
++	struct au_icntnr *c;
++
++	c = au_cache_alloc_icntnr();
++	if (c) {
++		au_icntnr_init(c);
++		c->vfs_inode.i_version = 1; /* sigen(sb); */
++		c->iinfo.ii_hinode = NULL;
++		return &c->vfs_inode;
++	}
++	return NULL;
++}
++
++static void aufs_destroy_inode_cb(struct rcu_head *head)
++{
++	struct inode *inode = container_of(head, struct inode, i_rcu);
++
++	INIT_HLIST_HEAD(&inode->i_dentry);
++	au_cache_free_icntnr(container_of(inode, struct au_icntnr, vfs_inode));
++}
++
++static void aufs_destroy_inode(struct inode *inode)
++{
++	au_iinfo_fin(inode);
++	call_rcu(&inode->i_rcu, aufs_destroy_inode_cb);
++}
++
++struct inode *au_iget_locked(struct super_block *sb, ino_t ino)
++{
++	struct inode *inode;
++	int err;
++
++	inode = iget_locked(sb, ino);
++	if (unlikely(!inode)) {
++		inode = ERR_PTR(-ENOMEM);
++		goto out;
++	}
++	if (!(inode->i_state & I_NEW))
++		goto out;
++
++	err = au_xigen_new(inode);
++	if (!err)
++		err = au_iinfo_init(inode);
++	if (!err)
++		inode->i_version++;
++	else {
++		iget_failed(inode);
++		inode = ERR_PTR(err);
++	}
++
++out:
++	/* never return NULL */
++	AuDebugOn(!inode);
++	AuTraceErrPtr(inode);
++	return inode;
++}
++
++/* lock free root dinfo */
++static int au_show_brs(struct seq_file *seq, struct super_block *sb)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	struct path path;
++	struct au_hdentry *hdp;
++	struct au_branch *br;
++	au_br_perm_str_t perm;
++
++	err = 0;
++	bend = au_sbend(sb);
++	hdp = au_di(sb->s_root)->di_hdentry;
++	for (bindex = 0; !err && bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		path.mnt = au_br_mnt(br);
++		path.dentry = hdp[bindex].hd_dentry;
++		err = au_seq_path(seq, &path);
++		if (err > 0) {
++			au_optstr_br_perm(&perm, br->br_perm);
++			err = seq_printf(seq, "=%s", perm.a);
++			if (err == -1)
++				err = -E2BIG;
++		}
++		if (!err && bindex != bend)
++			err = seq_putc(seq, ':');
++	}
++
++	return err;
++}
++
++static void au_show_wbr_create(struct seq_file *m, int v,
++			       struct au_sbinfo *sbinfo)
++{
++	const char *pat;
++
++	AuRwMustAnyLock(&sbinfo->si_rwsem);
++
++	seq_puts(m, ",create=");
++	pat = au_optstr_wbr_create(v);
++	switch (v) {
++	case AuWbrCreate_TDP:
++	case AuWbrCreate_RR:
++	case AuWbrCreate_MFS:
++	case AuWbrCreate_PMFS:
++		seq_puts(m, pat);
++		break;
++	case AuWbrCreate_MFSV:
++		seq_printf(m, /*pat*/"mfs:%lu",
++			   jiffies_to_msecs(sbinfo->si_wbr_mfs.mfs_expire)
++			   / MSEC_PER_SEC);
++		break;
++	case AuWbrCreate_PMFSV:
++		seq_printf(m, /*pat*/"pmfs:%lu",
++			   jiffies_to_msecs(sbinfo->si_wbr_mfs.mfs_expire)
++			   / MSEC_PER_SEC);
++		break;
++	case AuWbrCreate_MFSRR:
++		seq_printf(m, /*pat*/"mfsrr:%llu",
++			   sbinfo->si_wbr_mfs.mfsrr_watermark);
++		break;
++	case AuWbrCreate_MFSRRV:
++		seq_printf(m, /*pat*/"mfsrr:%llu:%lu",
++			   sbinfo->si_wbr_mfs.mfsrr_watermark,
++			   jiffies_to_msecs(sbinfo->si_wbr_mfs.mfs_expire)
++			   / MSEC_PER_SEC);
++		break;
++	case AuWbrCreate_PMFSRR:
++		seq_printf(m, /*pat*/"pmfsrr:%llu",
++			   sbinfo->si_wbr_mfs.mfsrr_watermark);
++		break;
++	case AuWbrCreate_PMFSRRV:
++		seq_printf(m, /*pat*/"pmfsrr:%llu:%lu",
++			   sbinfo->si_wbr_mfs.mfsrr_watermark,
++			   jiffies_to_msecs(sbinfo->si_wbr_mfs.mfs_expire)
++			   / MSEC_PER_SEC);
++		break;
++	}
++}
++
++static int au_show_xino(struct seq_file *seq, struct super_block *sb)
++{
++#ifdef CONFIG_SYSFS
++	return 0;
++#else
++	int err;
++	const int len = sizeof(AUFS_XINO_FNAME) - 1;
++	aufs_bindex_t bindex, brid;
++	struct qstr *name;
++	struct file *f;
++	struct dentry *d, *h_root;
++	struct au_hdentry *hdp;
++
++	AuRwMustAnyLock(&sbinfo->si_rwsem);
++
++	err = 0;
++	f = au_sbi(sb)->si_xib;
++	if (!f)
++		goto out;
++
++	/* stop printing the default xino path on the first writable branch */
++	h_root = NULL;
++	brid = au_xino_brid(sb);
++	if (brid >= 0) {
++		bindex = au_br_index(sb, brid);
++		hdp = au_di(sb->s_root)->di_hdentry;
++		h_root = hdp[0 + bindex].hd_dentry;
++	}
++	d = f->f_path.dentry;
++	name = &d->d_name;
++	/* safe ->d_parent because the file is unlinked */
++	if (d->d_parent == h_root
++	    && name->len == len
++	    && !memcmp(name->name, AUFS_XINO_FNAME, len))
++		goto out;
++
++	seq_puts(seq, ",xino=");
++	err = au_xino_path(seq, f);
++
++out:
++	return err;
++#endif
++}
++
++/* seq_file will re-call me in case of too long string */
++static int aufs_show_options(struct seq_file *m, struct dentry *dentry)
++{
++	int err;
++	unsigned int mnt_flags, v;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++
++#define AuBool(name, str) do { \
++	v = au_opt_test(mnt_flags, name); \
++	if (v != au_opt_test(AuOpt_Def, name)) \
++		seq_printf(m, ",%s" #str, v ? "" : "no"); \
++} while (0)
++
++#define AuStr(name, str) do { \
++	v = mnt_flags & AuOptMask_##name; \
++	if (v != (AuOpt_Def & AuOptMask_##name)) \
++		seq_printf(m, "," #str "=%s", au_optstr_##str(v)); \
++} while (0)
++
++#define AuUInt(name, str, val) do { \
++	if (val != AUFS_##name##_DEF) \
++		seq_printf(m, "," #str "=%u", val); \
++} while (0)
++
++	sb = dentry->d_sb;
++	if (sb->s_flags & MS_POSIXACL)
++		seq_puts(m, ",acl");
++
++	/* lock free root dinfo */
++	si_noflush_read_lock(sb);
++	sbinfo = au_sbi(sb);
++	seq_printf(m, ",si=%lx", sysaufs_si_id(sbinfo));
++
++	mnt_flags = au_mntflags(sb);
++	if (au_opt_test(mnt_flags, XINO)) {
++		err = au_show_xino(m, sb);
++		if (unlikely(err))
++			goto out;
++	} else
++		seq_puts(m, ",noxino");
++
++	AuBool(TRUNC_XINO, trunc_xino);
++	AuStr(UDBA, udba);
++	AuBool(SHWH, shwh);
++	AuBool(PLINK, plink);
++	AuBool(DIO, dio);
++	AuBool(DIRPERM1, dirperm1);
++
++	v = sbinfo->si_wbr_create;
++	if (v != AuWbrCreate_Def)
++		au_show_wbr_create(m, v, sbinfo);
++
++	v = sbinfo->si_wbr_copyup;
++	if (v != AuWbrCopyup_Def)
++		seq_printf(m, ",cpup=%s", au_optstr_wbr_copyup(v));
++
++	v = au_opt_test(mnt_flags, ALWAYS_DIROPQ);
++	if (v != au_opt_test(AuOpt_Def, ALWAYS_DIROPQ))
++		seq_printf(m, ",diropq=%c", v ? 'a' : 'w');
++
++	AuUInt(DIRWH, dirwh, sbinfo->si_dirwh);
++
++	v = jiffies_to_msecs(sbinfo->si_rdcache) / MSEC_PER_SEC;
++	AuUInt(RDCACHE, rdcache, v);
++
++	AuUInt(RDBLK, rdblk, sbinfo->si_rdblk);
++	AuUInt(RDHASH, rdhash, sbinfo->si_rdhash);
++
++	au_fhsm_show(m, sbinfo);
++
++	AuBool(SUM, sum);
++	/* AuBool(SUM_W, wsum); */
++	AuBool(WARN_PERM, warn_perm);
++	AuBool(VERBOSE, verbose);
++
++out:
++	/* be sure to print "br:" last */
++	if (!sysaufs_brs) {
++		seq_puts(m, ",br:");
++		au_show_brs(m, sb);
++	}
++	si_read_unlock(sb);
++	return 0;
++
++#undef AuBool
++#undef AuStr
++#undef AuUInt
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* sum mode which returns the summation for statfs(2) */
++
++static u64 au_add_till_max(u64 a, u64 b)
++{
++	u64 old;
++
++	old = a;
++	a += b;
++	if (old <= a)
++		return a;
++	return ULLONG_MAX;
++}
++
++static u64 au_mul_till_max(u64 a, long mul)
++{
++	u64 old;
++
++	old = a;
++	a *= mul;
++	if (old <= a)
++		return a;
++	return ULLONG_MAX;
++}
++
++static int au_statfs_sum(struct super_block *sb, struct kstatfs *buf)
++{
++	int err;
++	long bsize, factor;
++	u64 blocks, bfree, bavail, files, ffree;
++	aufs_bindex_t bend, bindex, i;
++	unsigned char shared;
++	struct path h_path;
++	struct super_block *h_sb;
++
++	err = 0;
++	bsize = LONG_MAX;
++	files = 0;
++	ffree = 0;
++	blocks = 0;
++	bfree = 0;
++	bavail = 0;
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		h_path.mnt = au_sbr_mnt(sb, bindex);
++		h_sb = h_path.mnt->mnt_sb;
++		shared = 0;
++		for (i = 0; !shared && i < bindex; i++)
++			shared = (au_sbr_sb(sb, i) == h_sb);
++		if (shared)
++			continue;
++
++		/* sb->s_root for NFS is unreliable */
++		h_path.dentry = h_path.mnt->mnt_root;
++		err = vfs_statfs(&h_path, buf);
++		if (unlikely(err))
++			goto out;
++
++		if (bsize > buf->f_bsize) {
++			/*
++			 * we will reduce bsize, so we have to expand blocks
++			 * etc. to match them again
++			 */
++			factor = (bsize / buf->f_bsize);
++			blocks = au_mul_till_max(blocks, factor);
++			bfree = au_mul_till_max(bfree, factor);
++			bavail = au_mul_till_max(bavail, factor);
++			bsize = buf->f_bsize;
++		}
++
++		factor = (buf->f_bsize / bsize);
++		blocks = au_add_till_max(blocks,
++				au_mul_till_max(buf->f_blocks, factor));
++		bfree = au_add_till_max(bfree,
++				au_mul_till_max(buf->f_bfree, factor));
++		bavail = au_add_till_max(bavail,
++				au_mul_till_max(buf->f_bavail, factor));
++		files = au_add_till_max(files, buf->f_files);
++		ffree = au_add_till_max(ffree, buf->f_ffree);
++	}
++
++	buf->f_bsize = bsize;
++	buf->f_blocks = blocks;
++	buf->f_bfree = bfree;
++	buf->f_bavail = bavail;
++	buf->f_files = files;
++	buf->f_ffree = ffree;
++	buf->f_frsize = 0;
++
++out:
++	return err;
++}
++
++static int aufs_statfs(struct dentry *dentry, struct kstatfs *buf)
++{
++	int err;
++	struct path h_path;
++	struct super_block *sb;
++
++	/* lock free root dinfo */
++	sb = dentry->d_sb;
++	si_noflush_read_lock(sb);
++	if (!au_opt_test(au_mntflags(sb), SUM)) {
++		/* sb->s_root for NFS is unreliable */
++		h_path.mnt = au_sbr_mnt(sb, 0);
++		h_path.dentry = h_path.mnt->mnt_root;
++		err = vfs_statfs(&h_path, buf);
++	} else
++		err = au_statfs_sum(sb, buf);
++	si_read_unlock(sb);
++
++	if (!err) {
++		buf->f_type = AUFS_SUPER_MAGIC;
++		buf->f_namelen = AUFS_MAX_NAMELEN;
++		memset(&buf->f_fsid, 0, sizeof(buf->f_fsid));
++	}
++	/* buf->f_bsize = buf->f_blocks = buf->f_bfree = buf->f_bavail = -1; */
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int aufs_sync_fs(struct super_block *sb, int wait)
++{
++	int err, e;
++	aufs_bindex_t bend, bindex;
++	struct au_branch *br;
++	struct super_block *h_sb;
++
++	err = 0;
++	si_noflush_read_lock(sb);
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		if (!au_br_writable(br->br_perm))
++			continue;
++
++		h_sb = au_sbr_sb(sb, bindex);
++		if (h_sb->s_op->sync_fs) {
++			e = h_sb->s_op->sync_fs(h_sb, wait);
++			if (unlikely(e && !err))
++				err = e;
++			/* go on even if an error happens */
++		}
++	}
++	si_read_unlock(sb);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* final actions when unmounting a file system */
++static void aufs_put_super(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	sbinfo = au_sbi(sb);
++	if (!sbinfo)
++		return;
++
++	dbgaufs_si_fin(sbinfo);
++	kobject_put(&sbinfo->si_kobj);
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_array_free(void *array)
++{
++	if (array) {
++		if (!is_vmalloc_addr(array))
++			kfree(array);
++		else
++			vfree(array);
++	}
++}
++
++void *au_array_alloc(unsigned long long *hint, au_arraycb_t cb, void *arg)
++{
++	void *array;
++	unsigned long long n, sz;
++
++	array = NULL;
++	n = 0;
++	if (!*hint)
++		goto out;
++
++	if (*hint > ULLONG_MAX / sizeof(array)) {
++		array = ERR_PTR(-EMFILE);
++		pr_err("hint %llu\n", *hint);
++		goto out;
++	}
++
++	sz = sizeof(array) * *hint;
++	array = kzalloc(sz, GFP_NOFS);
++	if (unlikely(!array))
++		array = vzalloc(sz);
++	if (unlikely(!array)) {
++		array = ERR_PTR(-ENOMEM);
++		goto out;
++	}
++
++	n = cb(array, *hint, arg);
++	AuDebugOn(n > *hint);
++
++out:
++	*hint = n;
++	return array;
++}
++
++static unsigned long long au_iarray_cb(void *a,
++				       unsigned long long max __maybe_unused,
++				       void *arg)
++{
++	unsigned long long n;
++	struct inode **p, *inode;
++	struct list_head *head;
++
++	n = 0;
++	p = a;
++	head = arg;
++	spin_lock(&inode_sb_list_lock);
++	list_for_each_entry(inode, head, i_sb_list) {
++		if (!is_bad_inode(inode)
++		    && au_ii(inode)->ii_bstart >= 0) {
++			spin_lock(&inode->i_lock);
++			if (atomic_read(&inode->i_count)) {
++				au_igrab(inode);
++				*p++ = inode;
++				n++;
++				AuDebugOn(n > max);
++			}
++			spin_unlock(&inode->i_lock);
++		}
++	}
++	spin_unlock(&inode_sb_list_lock);
++
++	return n;
++}
++
++struct inode **au_iarray_alloc(struct super_block *sb, unsigned long long *max)
++{
++	*max = atomic_long_read(&au_sbi(sb)->si_ninodes);
++	return au_array_alloc(max, au_iarray_cb, &sb->s_inodes);
++}
++
++void au_iarray_free(struct inode **a, unsigned long long max)
++{
++	unsigned long long ull;
++
++	for (ull = 0; ull < max; ull++)
++		iput(a[ull]);
++	au_array_free(a);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * refresh dentry and inode at remount time.
++ */
++/* todo: consolidate with simple_reval_dpath() and au_reval_for_attr() */
++static int au_do_refresh(struct dentry *dentry, unsigned int dir_flags,
++		      struct dentry *parent)
++{
++	int err;
++
++	di_write_lock_child(dentry);
++	di_read_lock_parent(parent, AuLock_IR);
++	err = au_refresh_dentry(dentry, parent);
++	if (!err && dir_flags)
++		au_hn_reset(dentry->d_inode, dir_flags);
++	di_read_unlock(parent, AuLock_IR);
++	di_write_unlock(dentry);
++
++	return err;
++}
++
++static int au_do_refresh_d(struct dentry *dentry, unsigned int sigen,
++			   struct au_sbinfo *sbinfo,
++			   const unsigned int dir_flags)
++{
++	int err;
++	struct dentry *parent;
++	struct inode *inode;
++
++	err = 0;
++	parent = dget_parent(dentry);
++	if (!au_digen_test(parent, sigen) && au_digen_test(dentry, sigen)) {
++		inode = dentry->d_inode;
++		if (inode) {
++			if (!S_ISDIR(inode->i_mode))
++				err = au_do_refresh(dentry, /*dir_flags*/0,
++						 parent);
++			else {
++				err = au_do_refresh(dentry, dir_flags, parent);
++				if (unlikely(err))
++					au_fset_si(sbinfo, FAILED_REFRESH_DIR);
++			}
++		} else
++			err = au_do_refresh(dentry, /*dir_flags*/0, parent);
++		AuDbgDentry(dentry);
++	}
++	dput(parent);
++
++	AuTraceErr(err);
++	return err;
++}
++
++static int au_refresh_d(struct super_block *sb)
++{
++	int err, i, j, ndentry, e;
++	unsigned int sigen;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry **dentries, *d;
++	struct au_sbinfo *sbinfo;
++	struct dentry *root = sb->s_root;
++	const unsigned int dir_flags = au_hi_flags(root->d_inode, /*isdir*/1);
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	err = au_dcsub_pages(&dpages, root, NULL, NULL);
++	if (unlikely(err))
++		goto out_dpages;
++
++	sigen = au_sigen(sb);
++	sbinfo = au_sbi(sb);
++	for (i = 0; i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		ndentry = dpage->ndentry;
++		for (j = 0; j < ndentry; j++) {
++			d = dentries[j];
++			e = au_do_refresh_d(d, sigen, sbinfo, dir_flags);
++			if (unlikely(e && !err))
++				err = e;
++			/* go on even err */
++		}
++	}
++
++out_dpages:
++	au_dpages_free(&dpages);
++out:
++	return err;
++}
++
++static int au_refresh_i(struct super_block *sb)
++{
++	int err, e;
++	unsigned int sigen;
++	unsigned long long max, ull;
++	struct inode *inode, **array;
++
++	array = au_iarray_alloc(sb, &max);
++	err = PTR_ERR(array);
++	if (IS_ERR(array))
++		goto out;
++
++	err = 0;
++	sigen = au_sigen(sb);
++	for (ull = 0; ull < max; ull++) {
++		inode = array[ull];
++		if (unlikely(!inode))
++			break;
++		if (au_iigen(inode, NULL) != sigen) {
++			ii_write_lock_child(inode);
++			e = au_refresh_hinode_self(inode);
++			ii_write_unlock(inode);
++			if (unlikely(e)) {
++				pr_err("error %d, i%lu\n", e, inode->i_ino);
++				if (!err)
++					err = e;
++				/* go on even if err */
++			}
++		}
++	}
++
++	au_iarray_free(array, max);
++
++out:
++	return err;
++}
++
++static void au_remount_refresh(struct super_block *sb)
++{
++	int err, e;
++	unsigned int udba;
++	aufs_bindex_t bindex, bend;
++	struct dentry *root;
++	struct inode *inode;
++	struct au_branch *br;
++
++	au_sigen_inc(sb);
++	au_fclr_si(au_sbi(sb), FAILED_REFRESH_DIR);
++
++	root = sb->s_root;
++	DiMustNoWaiters(root);
++	inode = root->d_inode;
++	IiMustNoWaiters(inode);
++
++	udba = au_opt_udba(sb);
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		err = au_hnotify_reset_br(udba, br, br->br_perm);
++		if (unlikely(err))
++			AuIOErr("hnotify failed on br %d, %d, ignored\n",
++				bindex, err);
++		/* go on even if err */
++	}
++	au_hn_reset(inode, au_hi_flags(inode, /*isdir*/1));
++
++	di_write_unlock(root);
++	err = au_refresh_d(sb);
++	e = au_refresh_i(sb);
++	if (unlikely(e && !err))
++		err = e;
++	/* aufs_write_lock() calls ..._child() */
++	di_write_lock_child(root);
++
++	au_cpup_attr_all(inode, /*force*/1);
++
++	if (unlikely(err))
++		AuIOErr("refresh failed, ignored, %d\n", err);
++}
++
++/* stop extra interpretation of errno in mount(8), and strange error messages */
++static int cvt_err(int err)
++{
++	AuTraceErr(err);
++
++	switch (err) {
++	case -ENOENT:
++	case -ENOTDIR:
++	case -EEXIST:
++	case -EIO:
++		err = -EINVAL;
++	}
++	return err;
++}
++
++static int aufs_remount_fs(struct super_block *sb, int *flags, char *data)
++{
++	int err, do_dx;
++	unsigned int mntflags;
++	struct au_opts opts;
++	struct dentry *root;
++	struct inode *inode;
++	struct au_sbinfo *sbinfo;
++
++	err = 0;
++	root = sb->s_root;
++	if (!data || !*data) {
++		err = si_write_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++		if (!err) {
++			di_write_lock_child(root);
++			err = au_opts_verify(sb, *flags, /*pending*/0);
++			aufs_write_unlock(root);
++		}
++		goto out;
++	}
++
++	err = -ENOMEM;
++	memset(&opts, 0, sizeof(opts));
++	opts.opt = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!opts.opt))
++		goto out;
++	opts.max_opt = PAGE_SIZE / sizeof(*opts.opt);
++	opts.flags = AuOpts_REMOUNT;
++	opts.sb_flags = *flags;
++
++	/* parse it before aufs lock */
++	err = au_opts_parse(sb, data, &opts);
++	if (unlikely(err))
++		goto out_opts;
++
++	sbinfo = au_sbi(sb);
++	inode = root->d_inode;
++	mutex_lock(&inode->i_mutex);
++	err = si_write_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++	if (unlikely(err))
++		goto out_mtx;
++	di_write_lock_child(root);
++
++	/* au_opts_remount() may return an error */
++	err = au_opts_remount(sb, &opts);
++	au_opts_free(&opts);
++
++	if (au_ftest_opts(opts.flags, REFRESH))
++		au_remount_refresh(sb);
++
++	if (au_ftest_opts(opts.flags, REFRESH_DYAOP)) {
++		mntflags = au_mntflags(sb);
++		do_dx = !!au_opt_test(mntflags, DIO);
++		au_dy_arefresh(do_dx);
++	}
++
++	au_fhsm_wrote_all(sb, /*force*/1); /* ?? */
++	aufs_write_unlock(root);
++
++out_mtx:
++	mutex_unlock(&inode->i_mutex);
++out_opts:
++	free_page((unsigned long)opts.opt);
++out:
++	err = cvt_err(err);
++	AuTraceErr(err);
++	return err;
++}
++
++static const struct super_operations aufs_sop = {
++	.alloc_inode	= aufs_alloc_inode,
++	.destroy_inode	= aufs_destroy_inode,
++	/* always deleting, no clearing */
++	.drop_inode	= generic_delete_inode,
++	.show_options	= aufs_show_options,
++	.statfs		= aufs_statfs,
++	.put_super	= aufs_put_super,
++	.sync_fs	= aufs_sync_fs,
++	.remount_fs	= aufs_remount_fs
++};
++
++/* ---------------------------------------------------------------------- */
++
++static int alloc_root(struct super_block *sb)
++{
++	int err;
++	struct inode *inode;
++	struct dentry *root;
++
++	err = -ENOMEM;
++	inode = au_iget_locked(sb, AUFS_ROOT_INO);
++	err = PTR_ERR(inode);
++	if (IS_ERR(inode))
++		goto out;
++
++	inode->i_op = &aufs_dir_iop;
++	inode->i_fop = &aufs_dir_fop;
++	inode->i_mode = S_IFDIR;
++	set_nlink(inode, 2);
++	unlock_new_inode(inode);
++
++	root = d_make_root(inode);
++	if (unlikely(!root))
++		goto out;
++	err = PTR_ERR(root);
++	if (IS_ERR(root))
++		goto out;
++
++	err = au_di_init(root);
++	if (!err) {
++		sb->s_root = root;
++		return 0; /* success */
++	}
++	dput(root);
++
++out:
++	return err;
++}
++
++static int aufs_fill_super(struct super_block *sb, void *raw_data,
++			   int silent __maybe_unused)
++{
++	int err;
++	struct au_opts opts;
++	struct dentry *root;
++	struct inode *inode;
++	char *arg = raw_data;
++
++	if (unlikely(!arg || !*arg)) {
++		err = -EINVAL;
++		pr_err("no arg\n");
++		goto out;
++	}
++
++	err = -ENOMEM;
++	memset(&opts, 0, sizeof(opts));
++	opts.opt = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!opts.opt))
++		goto out;
++	opts.max_opt = PAGE_SIZE / sizeof(*opts.opt);
++	opts.sb_flags = sb->s_flags;
++
++	err = au_si_alloc(sb);
++	if (unlikely(err))
++		goto out_opts;
++
++	/* all timestamps always follow the ones on the branch */
++	sb->s_flags |= MS_NOATIME | MS_NODIRATIME;
++	sb->s_op = &aufs_sop;
++	sb->s_d_op = &aufs_dop;
++	sb->s_magic = AUFS_SUPER_MAGIC;
++	sb->s_maxbytes = 0;
++	sb->s_stack_depth = 1;
++	au_export_init(sb);
++	/* au_xattr_init(sb); */
++
++	err = alloc_root(sb);
++	if (unlikely(err)) {
++		si_write_unlock(sb);
++		goto out_info;
++	}
++	root = sb->s_root;
++	inode = root->d_inode;
++
++	/*
++	 * actually we can parse options regardless aufs lock here.
++	 * but at remount time, parsing must be done before aufs lock.
++	 * so we follow the same rule.
++	 */
++	ii_write_lock_parent(inode);
++	aufs_write_unlock(root);
++	err = au_opts_parse(sb, arg, &opts);
++	if (unlikely(err))
++		goto out_root;
++
++	/* lock vfs_inode first, then aufs. */
++	mutex_lock(&inode->i_mutex);
++	aufs_write_lock(root);
++	err = au_opts_mount(sb, &opts);
++	au_opts_free(&opts);
++	aufs_write_unlock(root);
++	mutex_unlock(&inode->i_mutex);
++	if (!err)
++		goto out_opts; /* success */
++
++out_root:
++	dput(root);
++	sb->s_root = NULL;
++out_info:
++	dbgaufs_si_fin(au_sbi(sb));
++	kobject_put(&au_sbi(sb)->si_kobj);
++	sb->s_fs_info = NULL;
++out_opts:
++	free_page((unsigned long)opts.opt);
++out:
++	AuTraceErr(err);
++	err = cvt_err(err);
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct dentry *aufs_mount(struct file_system_type *fs_type, int flags,
++				 const char *dev_name __maybe_unused,
++				 void *raw_data)
++{
++	struct dentry *root;
++	struct super_block *sb;
++
++	/* all timestamps always follow the ones on the branch */
++	/* mnt->mnt_flags |= MNT_NOATIME | MNT_NODIRATIME; */
++	root = mount_nodev(fs_type, flags, raw_data, aufs_fill_super);
++	if (IS_ERR(root))
++		goto out;
++
++	sb = root->d_sb;
++	si_write_lock(sb, !AuLock_FLUSH);
++	sysaufs_brs_add(sb, 0);
++	si_write_unlock(sb);
++	au_sbilist_add(sb);
++
++out:
++	return root;
++}
++
++static void aufs_kill_sb(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	sbinfo = au_sbi(sb);
++	if (sbinfo) {
++		au_sbilist_del(sb);
++		aufs_write_lock(sb->s_root);
++		au_fhsm_fin(sb);
++		if (sbinfo->si_wbr_create_ops->fin)
++			sbinfo->si_wbr_create_ops->fin(sb);
++		if (au_opt_test(sbinfo->si_mntflags, UDBA_HNOTIFY)) {
++			au_opt_set_udba(sbinfo->si_mntflags, UDBA_NONE);
++			au_remount_refresh(sb);
++		}
++		if (au_opt_test(sbinfo->si_mntflags, PLINK))
++			au_plink_put(sb, /*verbose*/1);
++		au_xino_clr(sb);
++		sbinfo->si_sb = NULL;
++		aufs_write_unlock(sb->s_root);
++		au_nwt_flush(&sbinfo->si_nowait);
++	}
++	kill_anon_super(sb);
++}
++
++struct file_system_type aufs_fs_type = {
++	.name		= AUFS_FSTYPE,
++	/* a race between rename and others */
++	.fs_flags	= FS_RENAME_DOES_D_MOVE,
++	.mount		= aufs_mount,
++	.kill_sb	= aufs_kill_sb,
++	/* no need to __module_get() and module_put(). */
++	.owner		= THIS_MODULE,
++};
+diff -Nur linux-4.0.4.orig/fs/aufs/super.h linux-4.0.4/fs/aufs/super.h
+--- linux-4.0.4.orig/fs/aufs/super.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/super.h	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,626 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * super_block operations
++ */
++
++#ifndef __AUFS_SUPER_H__
++#define __AUFS_SUPER_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/kobject.h>
++#include "rwsem.h"
++#include "spl.h"
++#include "wkq.h"
++
++typedef ssize_t (*au_readf_t)(struct file *, char __user *, size_t, loff_t *);
++typedef ssize_t (*au_writef_t)(struct file *, const char __user *, size_t,
++			       loff_t *);
++
++/* policies to select one among multiple writable branches */
++struct au_wbr_copyup_operations {
++	int (*copyup)(struct dentry *dentry);
++};
++
++#define AuWbr_DIR	1		/* target is a dir */
++#define AuWbr_PARENT	(1 << 1)	/* always require a parent */
++
++#define au_ftest_wbr(flags, name)	((flags) & AuWbr_##name)
++#define au_fset_wbr(flags, name)	{ (flags) |= AuWbr_##name; }
++#define au_fclr_wbr(flags, name)	{ (flags) &= ~AuWbr_##name; }
++
++struct au_wbr_create_operations {
++	int (*create)(struct dentry *dentry, unsigned int flags);
++	int (*init)(struct super_block *sb);
++	int (*fin)(struct super_block *sb);
++};
++
++struct au_wbr_mfs {
++	struct mutex	mfs_lock; /* protect this structure */
++	unsigned long	mfs_jiffy;
++	unsigned long	mfs_expire;
++	aufs_bindex_t	mfs_bindex;
++
++	unsigned long long	mfsrr_bytes;
++	unsigned long long	mfsrr_watermark;
++};
++
++struct pseudo_link {
++	union {
++		struct hlist_node hlist;
++		struct rcu_head rcu;
++	};
++	struct inode *inode;
++};
++
++#define AuPlink_NHASH 100
++static inline int au_plink_hash(ino_t ino)
++{
++	return ino % AuPlink_NHASH;
++}
++
++/* File-based Hierarchical Storage Management */
++struct au_fhsm {
++#ifdef CONFIG_AUFS_FHSM
++	/* allow only one process who can receive the notification */
++	spinlock_t		fhsm_spin;
++	pid_t			fhsm_pid;
++	wait_queue_head_t	fhsm_wqh;
++	atomic_t		fhsm_readable;
++
++	/* these are protected by si_rwsem */
++	unsigned long		fhsm_expire;
++	aufs_bindex_t		fhsm_bottom;
++#endif
++};
++
++struct au_branch;
++struct au_sbinfo {
++	/* nowait tasks in the system-wide workqueue */
++	struct au_nowait_tasks	si_nowait;
++
++	/*
++	 * tried sb->s_umount, but failed due to the dependecy between i_mutex.
++	 * rwsem for au_sbinfo is necessary.
++	 */
++	struct au_rwsem		si_rwsem;
++
++	/* prevent recursive locking in deleting inode */
++	struct {
++		unsigned long		*bitmap;
++		spinlock_t		tree_lock;
++		struct radix_tree_root	tree;
++	} au_si_pid;
++
++	/*
++	 * dirty approach to protect sb->sb_inodes and ->s_files (gone) from
++	 * remount.
++	 */
++	atomic_long_t		si_ninodes, si_nfiles;
++
++	/* branch management */
++	unsigned int		si_generation;
++
++	/* see AuSi_ flags */
++	unsigned char		au_si_status;
++
++	aufs_bindex_t		si_bend;
++
++	/* dirty trick to keep br_id plus */
++	unsigned int		si_last_br_id :
++				sizeof(aufs_bindex_t) * BITS_PER_BYTE - 1;
++	struct au_branch	**si_branch;
++
++	/* policy to select a writable branch */
++	unsigned char		si_wbr_copyup;
++	unsigned char		si_wbr_create;
++	struct au_wbr_copyup_operations *si_wbr_copyup_ops;
++	struct au_wbr_create_operations *si_wbr_create_ops;
++
++	/* round robin */
++	atomic_t		si_wbr_rr_next;
++
++	/* most free space */
++	struct au_wbr_mfs	si_wbr_mfs;
++
++	/* File-based Hierarchical Storage Management */
++	struct au_fhsm		si_fhsm;
++
++	/* mount flags */
++	/* include/asm-ia64/siginfo.h defines a macro named si_flags */
++	unsigned int		si_mntflags;
++
++	/* external inode number (bitmap and translation table) */
++	au_readf_t		si_xread;
++	au_writef_t		si_xwrite;
++	struct file		*si_xib;
++	struct mutex		si_xib_mtx; /* protect xib members */
++	unsigned long		*si_xib_buf;
++	unsigned long		si_xib_last_pindex;
++	int			si_xib_next_bit;
++	aufs_bindex_t		si_xino_brid;
++	unsigned long		si_xino_jiffy;
++	unsigned long		si_xino_expire;
++	/* reserved for future use */
++	/* unsigned long long	si_xib_limit; */	/* Max xib file size */
++
++#ifdef CONFIG_AUFS_EXPORT
++	/* i_generation */
++	struct file		*si_xigen;
++	atomic_t		si_xigen_next;
++#endif
++
++	/* dirty trick to suppoer atomic_open */
++	struct au_sphlhead	si_aopen;
++
++	/* vdir parameters */
++	unsigned long		si_rdcache;	/* max cache time in jiffies */
++	unsigned int		si_rdblk;	/* deblk size */
++	unsigned int		si_rdhash;	/* hash size */
++
++	/*
++	 * If the number of whiteouts are larger than si_dirwh, leave all of
++	 * them after au_whtmp_ren to reduce the cost of rmdir(2).
++	 * future fsck.aufs or kernel thread will remove them later.
++	 * Otherwise, remove all whiteouts and the dir in rmdir(2).
++	 */
++	unsigned int		si_dirwh;
++
++	/* pseudo_link list */
++	struct au_sphlhead	si_plink[AuPlink_NHASH];
++	wait_queue_head_t	si_plink_wq;
++	spinlock_t		si_plink_maint_lock;
++	pid_t			si_plink_maint_pid;
++
++	/* file list */
++	struct au_sphlhead	si_files;
++
++	/*
++	 * sysfs and lifetime management.
++	 * this is not a small structure and it may be a waste of memory in case
++	 * of sysfs is disabled, particulary when many aufs-es are mounted.
++	 * but using sysfs is majority.
++	 */
++	struct kobject		si_kobj;
++#ifdef CONFIG_DEBUG_FS
++	struct dentry		 *si_dbgaufs;
++	struct dentry		 *si_dbgaufs_plink;
++	struct dentry		 *si_dbgaufs_xib;
++#ifdef CONFIG_AUFS_EXPORT
++	struct dentry		 *si_dbgaufs_xigen;
++#endif
++#endif
++
++#ifdef CONFIG_AUFS_SBILIST
++	struct list_head	si_list;
++#endif
++
++	/* dirty, necessary for unmounting, sysfs and sysrq */
++	struct super_block	*si_sb;
++};
++
++/* sbinfo status flags */
++/*
++ * set true when refresh_dirs() failed at remount time.
++ * then try refreshing dirs at access time again.
++ * if it is false, refreshing dirs at access time is unnecesary
++ */
++#define AuSi_FAILED_REFRESH_DIR	1
++
++#define AuSi_FHSM		(1 << 1)	/* fhsm is active now */
++
++#ifndef CONFIG_AUFS_FHSM
++#undef AuSi_FHSM
++#define AuSi_FHSM		0
++#endif
++
++static inline unsigned char au_do_ftest_si(struct au_sbinfo *sbi,
++					   unsigned int flag)
++{
++	AuRwMustAnyLock(&sbi->si_rwsem);
++	return sbi->au_si_status & flag;
++}
++#define au_ftest_si(sbinfo, name)	au_do_ftest_si(sbinfo, AuSi_##name)
++#define au_fset_si(sbinfo, name) do { \
++	AuRwMustWriteLock(&(sbinfo)->si_rwsem); \
++	(sbinfo)->au_si_status |= AuSi_##name; \
++} while (0)
++#define au_fclr_si(sbinfo, name) do { \
++	AuRwMustWriteLock(&(sbinfo)->si_rwsem); \
++	(sbinfo)->au_si_status &= ~AuSi_##name; \
++} while (0)
++
++/* ---------------------------------------------------------------------- */
++
++/* policy to select one among writable branches */
++#define AuWbrCopyup(sbinfo, ...) \
++	((sbinfo)->si_wbr_copyup_ops->copyup(__VA_ARGS__))
++#define AuWbrCreate(sbinfo, ...) \
++	((sbinfo)->si_wbr_create_ops->create(__VA_ARGS__))
++
++/* flags for si_read_lock()/aufs_read_lock()/di_read_lock() */
++#define AuLock_DW		1		/* write-lock dentry */
++#define AuLock_IR		(1 << 1)	/* read-lock inode */
++#define AuLock_IW		(1 << 2)	/* write-lock inode */
++#define AuLock_FLUSH		(1 << 3)	/* wait for 'nowait' tasks */
++#define AuLock_DIR		(1 << 4)	/* target is a dir */
++#define AuLock_NOPLM		(1 << 5)	/* return err in plm mode */
++#define AuLock_NOPLMW		(1 << 6)	/* wait for plm mode ends */
++#define AuLock_GEN		(1 << 7)	/* test digen/iigen */
++#define au_ftest_lock(flags, name)	((flags) & AuLock_##name)
++#define au_fset_lock(flags, name) \
++	do { (flags) |= AuLock_##name; } while (0)
++#define au_fclr_lock(flags, name) \
++	do { (flags) &= ~AuLock_##name; } while (0)
++
++/* ---------------------------------------------------------------------- */
++
++/* super.c */
++extern struct file_system_type aufs_fs_type;
++struct inode *au_iget_locked(struct super_block *sb, ino_t ino);
++typedef unsigned long long (*au_arraycb_t)(void *array, unsigned long long max,
++					   void *arg);
++void au_array_free(void *array);
++void *au_array_alloc(unsigned long long *hint, au_arraycb_t cb, void *arg);
++struct inode **au_iarray_alloc(struct super_block *sb, unsigned long long *max);
++void au_iarray_free(struct inode **a, unsigned long long max);
++
++/* sbinfo.c */
++void au_si_free(struct kobject *kobj);
++int au_si_alloc(struct super_block *sb);
++int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr);
++
++unsigned int au_sigen_inc(struct super_block *sb);
++aufs_bindex_t au_new_br_id(struct super_block *sb);
++
++int si_read_lock(struct super_block *sb, int flags);
++int si_write_lock(struct super_block *sb, int flags);
++int aufs_read_lock(struct dentry *dentry, int flags);
++void aufs_read_unlock(struct dentry *dentry, int flags);
++void aufs_write_lock(struct dentry *dentry);
++void aufs_write_unlock(struct dentry *dentry);
++int aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags);
++void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2);
++
++int si_pid_test_slow(struct super_block *sb);
++void si_pid_set_slow(struct super_block *sb);
++void si_pid_clr_slow(struct super_block *sb);
++
++/* wbr_policy.c */
++extern struct au_wbr_copyup_operations au_wbr_copyup_ops[];
++extern struct au_wbr_create_operations au_wbr_create_ops[];
++int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst);
++int au_wbr_nonopq(struct dentry *dentry, aufs_bindex_t bindex);
++int au_wbr_do_copyup_bu(struct dentry *dentry, aufs_bindex_t bstart);
++
++/* mvdown.c */
++int au_mvdown(struct dentry *dentry, struct aufs_mvdown __user *arg);
++
++#ifdef CONFIG_AUFS_FHSM
++/* fhsm.c */
++
++static inline pid_t au_fhsm_pid(struct au_fhsm *fhsm)
++{
++	pid_t pid;
++
++	spin_lock(&fhsm->fhsm_spin);
++	pid = fhsm->fhsm_pid;
++	spin_unlock(&fhsm->fhsm_spin);
++
++	return pid;
++}
++
++void au_fhsm_wrote(struct super_block *sb, aufs_bindex_t bindex, int force);
++void au_fhsm_wrote_all(struct super_block *sb, int force);
++int au_fhsm_fd(struct super_block *sb, int oflags);
++int au_fhsm_br_alloc(struct au_branch *br);
++void au_fhsm_set_bottom(struct super_block *sb, aufs_bindex_t bindex);
++void au_fhsm_fin(struct super_block *sb);
++void au_fhsm_init(struct au_sbinfo *sbinfo);
++void au_fhsm_set(struct au_sbinfo *sbinfo, unsigned int sec);
++void au_fhsm_show(struct seq_file *seq, struct au_sbinfo *sbinfo);
++#else
++AuStubVoid(au_fhsm_wrote, struct super_block *sb, aufs_bindex_t bindex,
++	   int force)
++AuStubVoid(au_fhsm_wrote_all, struct super_block *sb, int force)
++AuStub(int, au_fhsm_fd, return -EOPNOTSUPP, struct super_block *sb, int oflags)
++AuStub(pid_t, au_fhsm_pid, return 0, struct au_fhsm *fhsm)
++AuStubInt0(au_fhsm_br_alloc, struct au_branch *br)
++AuStubVoid(au_fhsm_set_bottom, struct super_block *sb, aufs_bindex_t bindex)
++AuStubVoid(au_fhsm_fin, struct super_block *sb)
++AuStubVoid(au_fhsm_init, struct au_sbinfo *sbinfo)
++AuStubVoid(au_fhsm_set, struct au_sbinfo *sbinfo, unsigned int sec)
++AuStubVoid(au_fhsm_show, struct seq_file *seq, struct au_sbinfo *sbinfo)
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct au_sbinfo *au_sbi(struct super_block *sb)
++{
++	return sb->s_fs_info;
++}
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_EXPORT
++int au_test_nfsd(void);
++void au_export_init(struct super_block *sb);
++void au_xigen_inc(struct inode *inode);
++int au_xigen_new(struct inode *inode);
++int au_xigen_set(struct super_block *sb, struct file *base);
++void au_xigen_clr(struct super_block *sb);
++
++static inline int au_busy_or_stale(void)
++{
++	if (!au_test_nfsd())
++		return -EBUSY;
++	return -ESTALE;
++}
++#else
++AuStubInt0(au_test_nfsd, void)
++AuStubVoid(au_export_init, struct super_block *sb)
++AuStubVoid(au_xigen_inc, struct inode *inode)
++AuStubInt0(au_xigen_new, struct inode *inode)
++AuStubInt0(au_xigen_set, struct super_block *sb, struct file *base)
++AuStubVoid(au_xigen_clr, struct super_block *sb)
++AuStub(int, au_busy_or_stale, return -EBUSY, void)
++#endif /* CONFIG_AUFS_EXPORT */
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_SBILIST
++/* module.c */
++extern struct au_splhead au_sbilist;
++
++static inline void au_sbilist_init(void)
++{
++	au_spl_init(&au_sbilist);
++}
++
++static inline void au_sbilist_add(struct super_block *sb)
++{
++	au_spl_add(&au_sbi(sb)->si_list, &au_sbilist);
++}
++
++static inline void au_sbilist_del(struct super_block *sb)
++{
++	au_spl_del(&au_sbi(sb)->si_list, &au_sbilist);
++}
++
++#ifdef CONFIG_AUFS_MAGIC_SYSRQ
++static inline void au_sbilist_lock(void)
++{
++	spin_lock(&au_sbilist.spin);
++}
++
++static inline void au_sbilist_unlock(void)
++{
++	spin_unlock(&au_sbilist.spin);
++}
++#define AuGFP_SBILIST	GFP_ATOMIC
++#else
++AuStubVoid(au_sbilist_lock, void)
++AuStubVoid(au_sbilist_unlock, void)
++#define AuGFP_SBILIST	GFP_NOFS
++#endif /* CONFIG_AUFS_MAGIC_SYSRQ */
++#else
++AuStubVoid(au_sbilist_init, void)
++AuStubVoid(au_sbilist_add, struct super_block *sb)
++AuStubVoid(au_sbilist_del, struct super_block *sb)
++AuStubVoid(au_sbilist_lock, void)
++AuStubVoid(au_sbilist_unlock, void)
++#define AuGFP_SBILIST	GFP_NOFS
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++static inline void dbgaufs_si_null(struct au_sbinfo *sbinfo)
++{
++	/*
++	 * This function is a dynamic '__init' function actually,
++	 * so the tiny check for si_rwsem is unnecessary.
++	 */
++	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
++#ifdef CONFIG_DEBUG_FS
++	sbinfo->si_dbgaufs = NULL;
++	sbinfo->si_dbgaufs_plink = NULL;
++	sbinfo->si_dbgaufs_xib = NULL;
++#ifdef CONFIG_AUFS_EXPORT
++	sbinfo->si_dbgaufs_xigen = NULL;
++#endif
++#endif
++}
++
++/* ---------------------------------------------------------------------- */
++
++static inline pid_t si_pid_bit(void)
++{
++	/* the origin of pid is 1, but the bitmap's is 0 */
++	return current->pid - 1;
++}
++
++static inline int si_pid_test(struct super_block *sb)
++{
++	pid_t bit;
++
++	bit = si_pid_bit();
++	if (bit < PID_MAX_DEFAULT)
++		return test_bit(bit, au_sbi(sb)->au_si_pid.bitmap);
++	return si_pid_test_slow(sb);
++}
++
++static inline void si_pid_set(struct super_block *sb)
++{
++	pid_t bit;
++
++	bit = si_pid_bit();
++	if (bit < PID_MAX_DEFAULT) {
++		AuDebugOn(test_bit(bit, au_sbi(sb)->au_si_pid.bitmap));
++		set_bit(bit, au_sbi(sb)->au_si_pid.bitmap);
++		/* smp_mb(); */
++	} else
++		si_pid_set_slow(sb);
++}
++
++static inline void si_pid_clr(struct super_block *sb)
++{
++	pid_t bit;
++
++	bit = si_pid_bit();
++	if (bit < PID_MAX_DEFAULT) {
++		AuDebugOn(!test_bit(bit, au_sbi(sb)->au_si_pid.bitmap));
++		clear_bit(bit, au_sbi(sb)->au_si_pid.bitmap);
++		/* smp_mb(); */
++	} else
++		si_pid_clr_slow(sb);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* lock superblock. mainly for entry point functions */
++/*
++ * __si_read_lock, __si_write_lock,
++ * __si_read_unlock, __si_write_unlock, __si_downgrade_lock
++ */
++AuSimpleRwsemFuncs(__si, struct super_block *sb, &au_sbi(sb)->si_rwsem);
++
++#define SiMustNoWaiters(sb)	AuRwMustNoWaiters(&au_sbi(sb)->si_rwsem)
++#define SiMustAnyLock(sb)	AuRwMustAnyLock(&au_sbi(sb)->si_rwsem)
++#define SiMustWriteLock(sb)	AuRwMustWriteLock(&au_sbi(sb)->si_rwsem)
++
++static inline void si_noflush_read_lock(struct super_block *sb)
++{
++	__si_read_lock(sb);
++	si_pid_set(sb);
++}
++
++static inline int si_noflush_read_trylock(struct super_block *sb)
++{
++	int locked;
++
++	locked = __si_read_trylock(sb);
++	if (locked)
++		si_pid_set(sb);
++	return locked;
++}
++
++static inline void si_noflush_write_lock(struct super_block *sb)
++{
++	__si_write_lock(sb);
++	si_pid_set(sb);
++}
++
++static inline int si_noflush_write_trylock(struct super_block *sb)
++{
++	int locked;
++
++	locked = __si_write_trylock(sb);
++	if (locked)
++		si_pid_set(sb);
++	return locked;
++}
++
++#if 0 /* reserved */
++static inline int si_read_trylock(struct super_block *sb, int flags)
++{
++	if (au_ftest_lock(flags, FLUSH))
++		au_nwt_flush(&au_sbi(sb)->si_nowait);
++	return si_noflush_read_trylock(sb);
++}
++#endif
++
++static inline void si_read_unlock(struct super_block *sb)
++{
++	si_pid_clr(sb);
++	__si_read_unlock(sb);
++}
++
++#if 0 /* reserved */
++static inline int si_write_trylock(struct super_block *sb, int flags)
++{
++	if (au_ftest_lock(flags, FLUSH))
++		au_nwt_flush(&au_sbi(sb)->si_nowait);
++	return si_noflush_write_trylock(sb);
++}
++#endif
++
++static inline void si_write_unlock(struct super_block *sb)
++{
++	si_pid_clr(sb);
++	__si_write_unlock(sb);
++}
++
++#if 0 /* reserved */
++static inline void si_downgrade_lock(struct super_block *sb)
++{
++	__si_downgrade_lock(sb);
++}
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++static inline aufs_bindex_t au_sbend(struct super_block *sb)
++{
++	SiMustAnyLock(sb);
++	return au_sbi(sb)->si_bend;
++}
++
++static inline unsigned int au_mntflags(struct super_block *sb)
++{
++	SiMustAnyLock(sb);
++	return au_sbi(sb)->si_mntflags;
++}
++
++static inline unsigned int au_sigen(struct super_block *sb)
++{
++	SiMustAnyLock(sb);
++	return au_sbi(sb)->si_generation;
++}
++
++static inline void au_ninodes_inc(struct super_block *sb)
++{
++	atomic_long_inc(&au_sbi(sb)->si_ninodes);
++}
++
++static inline void au_ninodes_dec(struct super_block *sb)
++{
++	AuDebugOn(!atomic_long_read(&au_sbi(sb)->si_ninodes));
++	atomic_long_dec(&au_sbi(sb)->si_ninodes);
++}
++
++static inline void au_nfiles_inc(struct super_block *sb)
++{
++	atomic_long_inc(&au_sbi(sb)->si_nfiles);
++}
++
++static inline void au_nfiles_dec(struct super_block *sb)
++{
++	AuDebugOn(!atomic_long_read(&au_sbi(sb)->si_nfiles));
++	atomic_long_dec(&au_sbi(sb)->si_nfiles);
++}
++
++static inline struct au_branch *au_sbr(struct super_block *sb,
++				       aufs_bindex_t bindex)
++{
++	SiMustAnyLock(sb);
++	return au_sbi(sb)->si_branch[0 + bindex];
++}
++
++static inline void au_xino_brid_set(struct super_block *sb, aufs_bindex_t brid)
++{
++	SiMustWriteLock(sb);
++	au_sbi(sb)->si_xino_brid = brid;
++}
++
++static inline aufs_bindex_t au_xino_brid(struct super_block *sb)
++{
++	SiMustAnyLock(sb);
++	return au_sbi(sb)->si_xino_brid;
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_SUPER_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/sysaufs.c linux-4.0.4/fs/aufs/sysaufs.c
+--- linux-4.0.4.orig/fs/aufs/sysaufs.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/sysaufs.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,91 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * sysfs interface and lifetime management
++ * they are necessary regardless sysfs is disabled.
++ */
++
++#include <linux/random.h>
++#include "aufs.h"
++
++unsigned long sysaufs_si_mask;
++struct kset *sysaufs_kset;
++
++#define AuSiAttr(_name) { \
++	.attr   = { .name = __stringify(_name), .mode = 0444 },	\
++	.show   = sysaufs_si_##_name,				\
++}
++
++static struct sysaufs_si_attr sysaufs_si_attr_xi_path = AuSiAttr(xi_path);
++struct attribute *sysaufs_si_attrs[] = {
++	&sysaufs_si_attr_xi_path.attr,
++	NULL,
++};
++
++static const struct sysfs_ops au_sbi_ops = {
++	.show   = sysaufs_si_show
++};
++
++static struct kobj_type au_sbi_ktype = {
++	.release	= au_si_free,
++	.sysfs_ops	= &au_sbi_ops,
++	.default_attrs	= sysaufs_si_attrs
++};
++
++/* ---------------------------------------------------------------------- */
++
++int sysaufs_si_init(struct au_sbinfo *sbinfo)
++{
++	int err;
++
++	sbinfo->si_kobj.kset = sysaufs_kset;
++	/* cf. sysaufs_name() */
++	err = kobject_init_and_add
++		(&sbinfo->si_kobj, &au_sbi_ktype, /*&sysaufs_kset->kobj*/NULL,
++		 SysaufsSiNamePrefix "%lx", sysaufs_si_id(sbinfo));
++
++	dbgaufs_si_null(sbinfo);
++	if (!err) {
++		err = dbgaufs_si_init(sbinfo);
++		if (unlikely(err))
++			kobject_put(&sbinfo->si_kobj);
++	}
++	return err;
++}
++
++void sysaufs_fin(void)
++{
++	dbgaufs_fin();
++	sysfs_remove_group(&sysaufs_kset->kobj, sysaufs_attr_group);
++	kset_unregister(sysaufs_kset);
++}
++
++int __init sysaufs_init(void)
++{
++	int err;
++
++	do {
++		get_random_bytes(&sysaufs_si_mask, sizeof(sysaufs_si_mask));
++	} while (!sysaufs_si_mask);
++
++	err = -EINVAL;
++	sysaufs_kset = kset_create_and_add(AUFS_NAME, NULL, fs_kobj);
++	if (unlikely(!sysaufs_kset))
++		goto out;
++	err = PTR_ERR(sysaufs_kset);
++	if (IS_ERR(sysaufs_kset))
++		goto out;
++	err = sysfs_create_group(&sysaufs_kset->kobj, sysaufs_attr_group);
++	if (unlikely(err)) {
++		kset_unregister(sysaufs_kset);
++		goto out;
++	}
++
++	err = dbgaufs_init();
++	if (unlikely(err))
++		sysaufs_fin();
++out:
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/sysaufs.h linux-4.0.4/fs/aufs/sysaufs.h
+--- linux-4.0.4.orig/fs/aufs/sysaufs.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/sysaufs.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,88 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * sysfs interface and mount lifetime management
++ */
++
++#ifndef __SYSAUFS_H__
++#define __SYSAUFS_H__
++
++#ifdef __KERNEL__
++
++#include <linux/sysfs.h>
++#include "module.h"
++
++struct super_block;
++struct au_sbinfo;
++
++struct sysaufs_si_attr {
++	struct attribute attr;
++	int (*show)(struct seq_file *seq, struct super_block *sb);
++};
++
++/* ---------------------------------------------------------------------- */
++
++/* sysaufs.c */
++extern unsigned long sysaufs_si_mask;
++extern struct kset *sysaufs_kset;
++extern struct attribute *sysaufs_si_attrs[];
++int sysaufs_si_init(struct au_sbinfo *sbinfo);
++int __init sysaufs_init(void);
++void sysaufs_fin(void);
++
++/* ---------------------------------------------------------------------- */
++
++/* some people doesn't like to show a pointer in kernel */
++static inline unsigned long sysaufs_si_id(struct au_sbinfo *sbinfo)
++{
++	return sysaufs_si_mask ^ (unsigned long)sbinfo;
++}
++
++#define SysaufsSiNamePrefix	"si_"
++#define SysaufsSiNameLen	(sizeof(SysaufsSiNamePrefix) + 16)
++static inline void sysaufs_name(struct au_sbinfo *sbinfo, char *name)
++{
++	snprintf(name, SysaufsSiNameLen, SysaufsSiNamePrefix "%lx",
++		 sysaufs_si_id(sbinfo));
++}
++
++struct au_branch;
++#ifdef CONFIG_SYSFS
++/* sysfs.c */
++extern struct attribute_group *sysaufs_attr_group;
++
++int sysaufs_si_xi_path(struct seq_file *seq, struct super_block *sb);
++ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
++			 char *buf);
++long au_brinfo_ioctl(struct file *file, unsigned long arg);
++#ifdef CONFIG_COMPAT
++long au_brinfo_compat_ioctl(struct file *file, unsigned long arg);
++#endif
++
++void sysaufs_br_init(struct au_branch *br);
++void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex);
++void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
++
++#define sysaufs_brs_init()	do {} while (0)
++
++#else
++#define sysaufs_attr_group	NULL
++
++AuStubInt0(sysaufs_si_xi_path, struct seq_file *seq, struct super_block *sb)
++AuStub(ssize_t, sysaufs_si_show, return 0, struct kobject *kobj,
++       struct attribute *attr, char *buf)
++AuStubVoid(sysaufs_br_init, struct au_branch *br)
++AuStubVoid(sysaufs_brs_add, struct super_block *sb, aufs_bindex_t bindex)
++AuStubVoid(sysaufs_brs_del, struct super_block *sb, aufs_bindex_t bindex)
++
++static inline void sysaufs_brs_init(void)
++{
++	sysaufs_brs = 0;
++}
++
++#endif /* CONFIG_SYSFS */
++
++#endif /* __KERNEL__ */
++#endif /* __SYSAUFS_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/sysfs.c linux-4.0.4/fs/aufs/sysfs.c
+--- linux-4.0.4.orig/fs/aufs/sysfs.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/sysfs.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,336 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * sysfs interface
++ */
++
++#include <linux/compat.h>
++#include <linux/seq_file.h>
++#include "aufs.h"
++
++static struct attribute *au_attr[] = {
++	NULL,	/* need to NULL terminate the list of attributes */
++};
++
++static struct attribute_group sysaufs_attr_group_body = {
++	.attrs = au_attr
++};
++
++struct attribute_group *sysaufs_attr_group = &sysaufs_attr_group_body;
++
++/* ---------------------------------------------------------------------- */
++
++int sysaufs_si_xi_path(struct seq_file *seq, struct super_block *sb)
++{
++	int err;
++
++	SiMustAnyLock(sb);
++
++	err = 0;
++	if (au_opt_test(au_mntflags(sb), XINO)) {
++		err = au_xino_path(seq, au_sbi(sb)->si_xib);
++		seq_putc(seq, '\n');
++	}
++	return err;
++}
++
++/*
++ * the lifetime of branch is independent from the entry under sysfs.
++ * sysfs handles the lifetime of the entry, and never call ->show() after it is
++ * unlinked.
++ */
++static int sysaufs_si_br(struct seq_file *seq, struct super_block *sb,
++			 aufs_bindex_t bindex, int idx)
++{
++	int err;
++	struct path path;
++	struct dentry *root;
++	struct au_branch *br;
++	au_br_perm_str_t perm;
++
++	AuDbg("b%d\n", bindex);
++
++	err = 0;
++	root = sb->s_root;
++	di_read_lock_parent(root, !AuLock_IR);
++	br = au_sbr(sb, bindex);
++
++	switch (idx) {
++	case AuBrSysfs_BR:
++		path.mnt = au_br_mnt(br);
++		path.dentry = au_h_dptr(root, bindex);
++		au_seq_path(seq, &path);
++		au_optstr_br_perm(&perm, br->br_perm);
++		err = seq_printf(seq, "=%s\n", perm.a);
++		break;
++	case AuBrSysfs_BRID:
++		err = seq_printf(seq, "%d\n", br->br_id);
++		break;
++	}
++	di_read_unlock(root, !AuLock_IR);
++	if (err == -1)
++		err = -E2BIG;
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static struct seq_file *au_seq(char *p, ssize_t len)
++{
++	struct seq_file *seq;
++
++	seq = kzalloc(sizeof(*seq), GFP_NOFS);
++	if (seq) {
++		/* mutex_init(&seq.lock); */
++		seq->buf = p;
++		seq->size = len;
++		return seq; /* success */
++	}
++
++	seq = ERR_PTR(-ENOMEM);
++	return seq;
++}
++
++#define SysaufsBr_PREFIX	"br"
++#define SysaufsBrid_PREFIX	"brid"
++
++/* todo: file size may exceed PAGE_SIZE */
++ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
++			char *buf)
++{
++	ssize_t err;
++	int idx;
++	long l;
++	aufs_bindex_t bend;
++	struct au_sbinfo *sbinfo;
++	struct super_block *sb;
++	struct seq_file *seq;
++	char *name;
++	struct attribute **cattr;
++
++	sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
++	sb = sbinfo->si_sb;
++
++	/*
++	 * prevent a race condition between sysfs and aufs.
++	 * for instance, sysfs_file_read() calls sysfs_get_active_two() which
++	 * prohibits maintaining the sysfs entries.
++	 * hew we acquire read lock after sysfs_get_active_two().
++	 * on the other hand, the remount process may maintain the sysfs/aufs
++	 * entries after acquiring write lock.
++	 * it can cause a deadlock.
++	 * simply we gave up processing read here.
++	 */
++	err = -EBUSY;
++	if (unlikely(!si_noflush_read_trylock(sb)))
++		goto out;
++
++	seq = au_seq(buf, PAGE_SIZE);
++	err = PTR_ERR(seq);
++	if (IS_ERR(seq))
++		goto out_unlock;
++
++	name = (void *)attr->name;
++	cattr = sysaufs_si_attrs;
++	while (*cattr) {
++		if (!strcmp(name, (*cattr)->name)) {
++			err = container_of(*cattr, struct sysaufs_si_attr, attr)
++				->show(seq, sb);
++			goto out_seq;
++		}
++		cattr++;
++	}
++
++	if (!strncmp(name, SysaufsBrid_PREFIX,
++		     sizeof(SysaufsBrid_PREFIX) - 1)) {
++		idx = AuBrSysfs_BRID;
++		name += sizeof(SysaufsBrid_PREFIX) - 1;
++	} else if (!strncmp(name, SysaufsBr_PREFIX,
++			    sizeof(SysaufsBr_PREFIX) - 1)) {
++		idx = AuBrSysfs_BR;
++		name += sizeof(SysaufsBr_PREFIX) - 1;
++	} else
++		  BUG();
++
++	err = kstrtol(name, 10, &l);
++	if (!err) {
++		bend = au_sbend(sb);
++		if (l <= bend)
++			err = sysaufs_si_br(seq, sb, (aufs_bindex_t)l, idx);
++		else
++			err = -ENOENT;
++	}
++
++out_seq:
++	if (!err) {
++		err = seq->count;
++		/* sysfs limit */
++		if (unlikely(err == PAGE_SIZE))
++			err = -EFBIG;
++	}
++	kfree(seq);
++out_unlock:
++	si_read_unlock(sb);
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_brinfo(struct super_block *sb, union aufs_brinfo __user *arg)
++{
++	int err;
++	int16_t brid;
++	aufs_bindex_t bindex, bend;
++	size_t sz;
++	char *buf;
++	struct seq_file *seq;
++	struct au_branch *br;
++
++	si_read_lock(sb, AuLock_FLUSH);
++	bend = au_sbend(sb);
++	err = bend + 1;
++	if (!arg)
++		goto out;
++
++	err = -ENOMEM;
++	buf = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!buf))
++		goto out;
++
++	seq = au_seq(buf, PAGE_SIZE);
++	err = PTR_ERR(seq);
++	if (IS_ERR(seq))
++		goto out_buf;
++
++	sz = sizeof(*arg) - offsetof(union aufs_brinfo, path);
++	for (bindex = 0; bindex <= bend; bindex++, arg++) {
++		err = !access_ok(VERIFY_WRITE, arg, sizeof(*arg));
++		if (unlikely(err))
++			break;
++
++		br = au_sbr(sb, bindex);
++		brid = br->br_id;
++		BUILD_BUG_ON(sizeof(brid) != sizeof(arg->id));
++		err = __put_user(brid, &arg->id);
++		if (unlikely(err))
++			break;
++
++		BUILD_BUG_ON(sizeof(br->br_perm) != sizeof(arg->perm));
++		err = __put_user(br->br_perm, &arg->perm);
++		if (unlikely(err))
++			break;
++
++		au_seq_path(seq, &br->br_path);
++		err = seq_putc(seq, '\0');
++		if (!err && seq->count <= sz) {
++			err = copy_to_user(arg->path, seq->buf, seq->count);
++			seq->count = 0;
++			if (unlikely(err))
++				break;
++		} else {
++			err = -E2BIG;
++			goto out_seq;
++		}
++	}
++	if (unlikely(err))
++		err = -EFAULT;
++
++out_seq:
++	kfree(seq);
++out_buf:
++	free_page((unsigned long)buf);
++out:
++	si_read_unlock(sb);
++	return err;
++}
++
++long au_brinfo_ioctl(struct file *file, unsigned long arg)
++{
++	return au_brinfo(file->f_path.dentry->d_sb, (void __user *)arg);
++}
++
++#ifdef CONFIG_COMPAT
++long au_brinfo_compat_ioctl(struct file *file, unsigned long arg)
++{
++	return au_brinfo(file->f_path.dentry->d_sb, compat_ptr(arg));
++}
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++void sysaufs_br_init(struct au_branch *br)
++{
++	int i;
++	struct au_brsysfs *br_sysfs;
++	struct attribute *attr;
++
++	br_sysfs = br->br_sysfs;
++	for (i = 0; i < ARRAY_SIZE(br->br_sysfs); i++) {
++		attr = &br_sysfs->attr;
++		sysfs_attr_init(attr);
++		attr->name = br_sysfs->name;
++		attr->mode = S_IRUGO;
++		br_sysfs++;
++	}
++}
++
++void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
++{
++	struct au_branch *br;
++	struct kobject *kobj;
++	struct au_brsysfs *br_sysfs;
++	int i;
++	aufs_bindex_t bend;
++
++	dbgaufs_brs_del(sb, bindex);
++
++	if (!sysaufs_brs)
++		return;
++
++	kobj = &au_sbi(sb)->si_kobj;
++	bend = au_sbend(sb);
++	for (; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		br_sysfs = br->br_sysfs;
++		for (i = 0; i < ARRAY_SIZE(br->br_sysfs); i++) {
++			sysfs_remove_file(kobj, &br_sysfs->attr);
++			br_sysfs++;
++		}
++	}
++}
++
++void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
++{
++	int err, i;
++	aufs_bindex_t bend;
++	struct kobject *kobj;
++	struct au_branch *br;
++	struct au_brsysfs *br_sysfs;
++
++	dbgaufs_brs_add(sb, bindex);
++
++	if (!sysaufs_brs)
++		return;
++
++	kobj = &au_sbi(sb)->si_kobj;
++	bend = au_sbend(sb);
++	for (; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		br_sysfs = br->br_sysfs;
++		snprintf(br_sysfs[AuBrSysfs_BR].name, sizeof(br_sysfs->name),
++			 SysaufsBr_PREFIX "%d", bindex);
++		snprintf(br_sysfs[AuBrSysfs_BRID].name, sizeof(br_sysfs->name),
++			 SysaufsBrid_PREFIX "%d", bindex);
++		for (i = 0; i < ARRAY_SIZE(br->br_sysfs); i++) {
++			err = sysfs_create_file(kobj, &br_sysfs->attr);
++			if (unlikely(err))
++				pr_warn("failed %s under sysfs(%d)\n",
++					br_sysfs->name, err);
++			br_sysfs++;
++		}
++	}
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/sysrq.c linux-4.0.4/fs/aufs/sysrq.c
+--- linux-4.0.4.orig/fs/aufs/sysrq.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/sysrq.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,144 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * magic sysrq hanlder
++ */
++
++/* #include <linux/sysrq.h> */
++#include <linux/writeback.h>
++#include "aufs.h"
++
++/* ---------------------------------------------------------------------- */
++
++static void sysrq_sb(struct super_block *sb)
++{
++	char *plevel;
++	struct au_sbinfo *sbinfo;
++	struct file *file;
++	struct au_sphlhead *files;
++	struct au_finfo *finfo;
++
++	plevel = au_plevel;
++	au_plevel = KERN_WARNING;
++
++	/* since we define pr_fmt, call printk directly */
++#define pr(str) printk(KERN_WARNING AUFS_NAME ": " str)
++
++	sbinfo = au_sbi(sb);
++	printk(KERN_WARNING "si=%lx\n", sysaufs_si_id(sbinfo));
++	pr("superblock\n");
++	au_dpri_sb(sb);
++
++#if 0
++	pr("root dentry\n");
++	au_dpri_dentry(sb->s_root);
++	pr("root inode\n");
++	au_dpri_inode(sb->s_root->d_inode);
++#endif
++
++#if 0
++	do {
++		int err, i, j, ndentry;
++		struct au_dcsub_pages dpages;
++		struct au_dpage *dpage;
++
++		err = au_dpages_init(&dpages, GFP_ATOMIC);
++		if (unlikely(err))
++			break;
++		err = au_dcsub_pages(&dpages, sb->s_root, NULL, NULL);
++		if (!err)
++			for (i = 0; i < dpages.ndpage; i++) {
++				dpage = dpages.dpages + i;
++				ndentry = dpage->ndentry;
++				for (j = 0; j < ndentry; j++)
++					au_dpri_dentry(dpage->dentries[j]);
++			}
++		au_dpages_free(&dpages);
++	} while (0);
++#endif
++
++#if 1
++	{
++		struct inode *i;
++
++		pr("isolated inode\n");
++		spin_lock(&inode_sb_list_lock);
++		list_for_each_entry(i, &sb->s_inodes, i_sb_list) {
++			spin_lock(&i->i_lock);
++			if (1 || hlist_empty(&i->i_dentry))
++				au_dpri_inode(i);
++			spin_unlock(&i->i_lock);
++		}
++		spin_unlock(&inode_sb_list_lock);
++	}
++#endif
++	pr("files\n");
++	files = &au_sbi(sb)->si_files;
++	spin_lock(&files->spin);
++	hlist_for_each_entry(finfo, &files->head, fi_hlist) {
++		umode_t mode;
++
++		file = finfo->fi_file;
++		mode = file_inode(file)->i_mode;
++		if (!special_file(mode))
++			au_dpri_file(file);
++	}
++	spin_unlock(&files->spin);
++	pr("done\n");
++
++#undef pr
++	au_plevel = plevel;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* module parameter */
++static char *aufs_sysrq_key = "a";
++module_param_named(sysrq, aufs_sysrq_key, charp, S_IRUGO);
++MODULE_PARM_DESC(sysrq, "MagicSysRq key for " AUFS_NAME);
++
++static void au_sysrq(int key __maybe_unused)
++{
++	struct au_sbinfo *sbinfo;
++
++	lockdep_off();
++	au_sbilist_lock();
++	list_for_each_entry(sbinfo, &au_sbilist.head, si_list)
++		sysrq_sb(sbinfo->si_sb);
++	au_sbilist_unlock();
++	lockdep_on();
++}
++
++static struct sysrq_key_op au_sysrq_op = {
++	.handler	= au_sysrq,
++	.help_msg	= "Aufs",
++	.action_msg	= "Aufs",
++	.enable_mask	= SYSRQ_ENABLE_DUMP
++};
++
++/* ---------------------------------------------------------------------- */
++
++int __init au_sysrq_init(void)
++{
++	int err;
++	char key;
++
++	err = -1;
++	key = *aufs_sysrq_key;
++	if ('a' <= key && key <= 'z')
++		err = register_sysrq_key(key, &au_sysrq_op);
++	if (unlikely(err))
++		pr_err("err %d, sysrq=%c\n", err, key);
++	return err;
++}
++
++void au_sysrq_fin(void)
++{
++	int err;
++
++	err = unregister_sysrq_key(*aufs_sysrq_key, &au_sysrq_op);
++	if (unlikely(err))
++		pr_err("err %d (ignored)\n", err);
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/vdir.c linux-4.0.4/fs/aufs/vdir.c
+--- linux-4.0.4.orig/fs/aufs/vdir.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/vdir.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,876 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * virtual or vertical directory
++ */
++
++#include "aufs.h"
++
++static unsigned int calc_size(int nlen)
++{
++	return ALIGN(sizeof(struct au_vdir_de) + nlen, sizeof(ino_t));
++}
++
++static int set_deblk_end(union au_vdir_deblk_p *p,
++			 union au_vdir_deblk_p *deblk_end)
++{
++	if (calc_size(0) <= deblk_end->deblk - p->deblk) {
++		p->de->de_str.len = 0;
++		/* smp_mb(); */
++		return 0;
++	}
++	return -1; /* error */
++}
++
++/* returns true or false */
++static int is_deblk_end(union au_vdir_deblk_p *p,
++			union au_vdir_deblk_p *deblk_end)
++{
++	if (calc_size(0) <= deblk_end->deblk - p->deblk)
++		return !p->de->de_str.len;
++	return 1;
++}
++
++static unsigned char *last_deblk(struct au_vdir *vdir)
++{
++	return vdir->vd_deblk[vdir->vd_nblk - 1];
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* estimate the apropriate size for name hash table */
++unsigned int au_rdhash_est(loff_t sz)
++{
++	unsigned int n;
++
++	n = UINT_MAX;
++	sz >>= 10;
++	if (sz < n)
++		n = sz;
++	if (sz < AUFS_RDHASH_DEF)
++		n = AUFS_RDHASH_DEF;
++	/* pr_info("n %u\n", n); */
++	return n;
++}
++
++/*
++ * the allocated memory has to be freed by
++ * au_nhash_wh_free() or au_nhash_de_free().
++ */
++int au_nhash_alloc(struct au_nhash *nhash, unsigned int num_hash, gfp_t gfp)
++{
++	struct hlist_head *head;
++	unsigned int u;
++	size_t sz;
++
++	sz = sizeof(*nhash->nh_head) * num_hash;
++	head = kmalloc(sz, gfp);
++	if (head) {
++		nhash->nh_num = num_hash;
++		nhash->nh_head = head;
++		for (u = 0; u < num_hash; u++)
++			INIT_HLIST_HEAD(head++);
++		return 0; /* success */
++	}
++
++	return -ENOMEM;
++}
++
++static void nhash_count(struct hlist_head *head)
++{
++#if 0
++	unsigned long n;
++	struct hlist_node *pos;
++
++	n = 0;
++	hlist_for_each(pos, head)
++		n++;
++	pr_info("%lu\n", n);
++#endif
++}
++
++static void au_nhash_wh_do_free(struct hlist_head *head)
++{
++	struct au_vdir_wh *pos;
++	struct hlist_node *node;
++
++	hlist_for_each_entry_safe(pos, node, head, wh_hash)
++		kfree(pos);
++}
++
++static void au_nhash_de_do_free(struct hlist_head *head)
++{
++	struct au_vdir_dehstr *pos;
++	struct hlist_node *node;
++
++	hlist_for_each_entry_safe(pos, node, head, hash)
++		au_cache_free_vdir_dehstr(pos);
++}
++
++static void au_nhash_do_free(struct au_nhash *nhash,
++			     void (*free)(struct hlist_head *head))
++{
++	unsigned int n;
++	struct hlist_head *head;
++
++	n = nhash->nh_num;
++	if (!n)
++		return;
++
++	head = nhash->nh_head;
++	while (n-- > 0) {
++		nhash_count(head);
++		free(head++);
++	}
++	kfree(nhash->nh_head);
++}
++
++void au_nhash_wh_free(struct au_nhash *whlist)
++{
++	au_nhash_do_free(whlist, au_nhash_wh_do_free);
++}
++
++static void au_nhash_de_free(struct au_nhash *delist)
++{
++	au_nhash_do_free(delist, au_nhash_de_do_free);
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
++			    int limit)
++{
++	int num;
++	unsigned int u, n;
++	struct hlist_head *head;
++	struct au_vdir_wh *pos;
++
++	num = 0;
++	n = whlist->nh_num;
++	head = whlist->nh_head;
++	for (u = 0; u < n; u++, head++)
++		hlist_for_each_entry(pos, head, wh_hash)
++			if (pos->wh_bindex == btgt && ++num > limit)
++				return 1;
++	return 0;
++}
++
++static struct hlist_head *au_name_hash(struct au_nhash *nhash,
++				       unsigned char *name,
++				       unsigned int len)
++{
++	unsigned int v;
++	/* const unsigned int magic_bit = 12; */
++
++	AuDebugOn(!nhash->nh_num || !nhash->nh_head);
++
++	v = 0;
++	while (len--)
++		v += *name++;
++	/* v = hash_long(v, magic_bit); */
++	v %= nhash->nh_num;
++	return nhash->nh_head + v;
++}
++
++static int au_nhash_test_name(struct au_vdir_destr *str, const char *name,
++			      int nlen)
++{
++	return str->len == nlen && !memcmp(str->name, name, nlen);
++}
++
++/* returns found or not */
++int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int nlen)
++{
++	struct hlist_head *head;
++	struct au_vdir_wh *pos;
++	struct au_vdir_destr *str;
++
++	head = au_name_hash(whlist, name, nlen);
++	hlist_for_each_entry(pos, head, wh_hash) {
++		str = &pos->wh_str;
++		AuDbg("%.*s\n", str->len, str->name);
++		if (au_nhash_test_name(str, name, nlen))
++			return 1;
++	}
++	return 0;
++}
++
++/* returns found(true) or not */
++static int test_known(struct au_nhash *delist, char *name, int nlen)
++{
++	struct hlist_head *head;
++	struct au_vdir_dehstr *pos;
++	struct au_vdir_destr *str;
++
++	head = au_name_hash(delist, name, nlen);
++	hlist_for_each_entry(pos, head, hash) {
++		str = pos->str;
++		AuDbg("%.*s\n", str->len, str->name);
++		if (au_nhash_test_name(str, name, nlen))
++			return 1;
++	}
++	return 0;
++}
++
++static void au_shwh_init_wh(struct au_vdir_wh *wh, ino_t ino,
++			    unsigned char d_type)
++{
++#ifdef CONFIG_AUFS_SHWH
++	wh->wh_ino = ino;
++	wh->wh_type = d_type;
++#endif
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_nhash_append_wh(struct au_nhash *whlist, char *name, int nlen, ino_t ino,
++		       unsigned int d_type, aufs_bindex_t bindex,
++		       unsigned char shwh)
++{
++	int err;
++	struct au_vdir_destr *str;
++	struct au_vdir_wh *wh;
++
++	AuDbg("%.*s\n", nlen, name);
++	AuDebugOn(!whlist->nh_num || !whlist->nh_head);
++
++	err = -ENOMEM;
++	wh = kmalloc(sizeof(*wh) + nlen, GFP_NOFS);
++	if (unlikely(!wh))
++		goto out;
++
++	err = 0;
++	wh->wh_bindex = bindex;
++	if (shwh)
++		au_shwh_init_wh(wh, ino, d_type);
++	str = &wh->wh_str;
++	str->len = nlen;
++	memcpy(str->name, name, nlen);
++	hlist_add_head(&wh->wh_hash, au_name_hash(whlist, name, nlen));
++	/* smp_mb(); */
++
++out:
++	return err;
++}
++
++static int append_deblk(struct au_vdir *vdir)
++{
++	int err;
++	unsigned long ul;
++	const unsigned int deblk_sz = vdir->vd_deblk_sz;
++	union au_vdir_deblk_p p, deblk_end;
++	unsigned char **o;
++
++	err = -ENOMEM;
++	o = krealloc(vdir->vd_deblk, sizeof(*o) * (vdir->vd_nblk + 1),
++		     GFP_NOFS);
++	if (unlikely(!o))
++		goto out;
++
++	vdir->vd_deblk = o;
++	p.deblk = kmalloc(deblk_sz, GFP_NOFS);
++	if (p.deblk) {
++		ul = vdir->vd_nblk++;
++		vdir->vd_deblk[ul] = p.deblk;
++		vdir->vd_last.ul = ul;
++		vdir->vd_last.p.deblk = p.deblk;
++		deblk_end.deblk = p.deblk + deblk_sz;
++		err = set_deblk_end(&p, &deblk_end);
++	}
++
++out:
++	return err;
++}
++
++static int append_de(struct au_vdir *vdir, char *name, int nlen, ino_t ino,
++		     unsigned int d_type, struct au_nhash *delist)
++{
++	int err;
++	unsigned int sz;
++	const unsigned int deblk_sz = vdir->vd_deblk_sz;
++	union au_vdir_deblk_p p, *room, deblk_end;
++	struct au_vdir_dehstr *dehstr;
++
++	p.deblk = last_deblk(vdir);
++	deblk_end.deblk = p.deblk + deblk_sz;
++	room = &vdir->vd_last.p;
++	AuDebugOn(room->deblk < p.deblk || deblk_end.deblk <= room->deblk
++		  || !is_deblk_end(room, &deblk_end));
++
++	sz = calc_size(nlen);
++	if (unlikely(sz > deblk_end.deblk - room->deblk)) {
++		err = append_deblk(vdir);
++		if (unlikely(err))
++			goto out;
++
++		p.deblk = last_deblk(vdir);
++		deblk_end.deblk = p.deblk + deblk_sz;
++		/* smp_mb(); */
++		AuDebugOn(room->deblk != p.deblk);
++	}
++
++	err = -ENOMEM;
++	dehstr = au_cache_alloc_vdir_dehstr();
++	if (unlikely(!dehstr))
++		goto out;
++
++	dehstr->str = &room->de->de_str;
++	hlist_add_head(&dehstr->hash, au_name_hash(delist, name, nlen));
++	room->de->de_ino = ino;
++	room->de->de_type = d_type;
++	room->de->de_str.len = nlen;
++	memcpy(room->de->de_str.name, name, nlen);
++
++	err = 0;
++	room->deblk += sz;
++	if (unlikely(set_deblk_end(room, &deblk_end)))
++		err = append_deblk(vdir);
++	/* smp_mb(); */
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_vdir_free(struct au_vdir *vdir)
++{
++	unsigned char **deblk;
++
++	deblk = vdir->vd_deblk;
++	while (vdir->vd_nblk--)
++		kfree(*deblk++);
++	kfree(vdir->vd_deblk);
++	au_cache_free_vdir(vdir);
++}
++
++static struct au_vdir *alloc_vdir(struct file *file)
++{
++	struct au_vdir *vdir;
++	struct super_block *sb;
++	int err;
++
++	sb = file->f_path.dentry->d_sb;
++	SiMustAnyLock(sb);
++
++	err = -ENOMEM;
++	vdir = au_cache_alloc_vdir();
++	if (unlikely(!vdir))
++		goto out;
++
++	vdir->vd_deblk = kzalloc(sizeof(*vdir->vd_deblk), GFP_NOFS);
++	if (unlikely(!vdir->vd_deblk))
++		goto out_free;
++
++	vdir->vd_deblk_sz = au_sbi(sb)->si_rdblk;
++	if (!vdir->vd_deblk_sz) {
++		/* estimate the apropriate size for deblk */
++		vdir->vd_deblk_sz = au_dir_size(file, /*dentry*/NULL);
++		/* pr_info("vd_deblk_sz %u\n", vdir->vd_deblk_sz); */
++	}
++	vdir->vd_nblk = 0;
++	vdir->vd_version = 0;
++	vdir->vd_jiffy = 0;
++	err = append_deblk(vdir);
++	if (!err)
++		return vdir; /* success */
++
++	kfree(vdir->vd_deblk);
++
++out_free:
++	au_cache_free_vdir(vdir);
++out:
++	vdir = ERR_PTR(err);
++	return vdir;
++}
++
++static int reinit_vdir(struct au_vdir *vdir)
++{
++	int err;
++	union au_vdir_deblk_p p, deblk_end;
++
++	while (vdir->vd_nblk > 1) {
++		kfree(vdir->vd_deblk[vdir->vd_nblk - 1]);
++		/* vdir->vd_deblk[vdir->vd_nblk - 1] = NULL; */
++		vdir->vd_nblk--;
++	}
++	p.deblk = vdir->vd_deblk[0];
++	deblk_end.deblk = p.deblk + vdir->vd_deblk_sz;
++	err = set_deblk_end(&p, &deblk_end);
++	/* keep vd_dblk_sz */
++	vdir->vd_last.ul = 0;
++	vdir->vd_last.p.deblk = vdir->vd_deblk[0];
++	vdir->vd_version = 0;
++	vdir->vd_jiffy = 0;
++	/* smp_mb(); */
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++#define AuFillVdir_CALLED	1
++#define AuFillVdir_WHABLE	(1 << 1)
++#define AuFillVdir_SHWH		(1 << 2)
++#define au_ftest_fillvdir(flags, name)	((flags) & AuFillVdir_##name)
++#define au_fset_fillvdir(flags, name) \
++	do { (flags) |= AuFillVdir_##name; } while (0)
++#define au_fclr_fillvdir(flags, name) \
++	do { (flags) &= ~AuFillVdir_##name; } while (0)
++
++#ifndef CONFIG_AUFS_SHWH
++#undef AuFillVdir_SHWH
++#define AuFillVdir_SHWH		0
++#endif
++
++struct fillvdir_arg {
++	struct dir_context	ctx;
++	struct file		*file;
++	struct au_vdir		*vdir;
++	struct au_nhash		delist;
++	struct au_nhash		whlist;
++	aufs_bindex_t		bindex;
++	unsigned int		flags;
++	int			err;
++};
++
++static int fillvdir(struct dir_context *ctx, const char *__name, int nlen,
++		    loff_t offset __maybe_unused, u64 h_ino,
++		    unsigned int d_type)
++{
++	struct fillvdir_arg *arg = container_of(ctx, struct fillvdir_arg, ctx);
++	char *name = (void *)__name;
++	struct super_block *sb;
++	ino_t ino;
++	const unsigned char shwh = !!au_ftest_fillvdir(arg->flags, SHWH);
++
++	arg->err = 0;
++	sb = arg->file->f_path.dentry->d_sb;
++	au_fset_fillvdir(arg->flags, CALLED);
++	/* smp_mb(); */
++	if (nlen <= AUFS_WH_PFX_LEN
++	    || memcmp(name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
++		if (test_known(&arg->delist, name, nlen)
++		    || au_nhash_test_known_wh(&arg->whlist, name, nlen))
++			goto out; /* already exists or whiteouted */
++
++		sb = arg->file->f_path.dentry->d_sb;
++		arg->err = au_ino(sb, arg->bindex, h_ino, d_type, &ino);
++		if (!arg->err) {
++			if (unlikely(nlen > AUFS_MAX_NAMELEN))
++				d_type = DT_UNKNOWN;
++			arg->err = append_de(arg->vdir, name, nlen, ino,
++					     d_type, &arg->delist);
++		}
++	} else if (au_ftest_fillvdir(arg->flags, WHABLE)) {
++		name += AUFS_WH_PFX_LEN;
++		nlen -= AUFS_WH_PFX_LEN;
++		if (au_nhash_test_known_wh(&arg->whlist, name, nlen))
++			goto out; /* already whiteouted */
++
++		if (shwh)
++			arg->err = au_wh_ino(sb, arg->bindex, h_ino, d_type,
++					     &ino);
++		if (!arg->err) {
++			if (nlen <= AUFS_MAX_NAMELEN + AUFS_WH_PFX_LEN)
++				d_type = DT_UNKNOWN;
++			arg->err = au_nhash_append_wh
++				(&arg->whlist, name, nlen, ino, d_type,
++				 arg->bindex, shwh);
++		}
++	}
++
++out:
++	if (!arg->err)
++		arg->vdir->vd_jiffy = jiffies;
++	/* smp_mb(); */
++	AuTraceErr(arg->err);
++	return arg->err;
++}
++
++static int au_handle_shwh(struct super_block *sb, struct au_vdir *vdir,
++			  struct au_nhash *whlist, struct au_nhash *delist)
++{
++#ifdef CONFIG_AUFS_SHWH
++	int err;
++	unsigned int nh, u;
++	struct hlist_head *head;
++	struct au_vdir_wh *pos;
++	struct hlist_node *n;
++	char *p, *o;
++	struct au_vdir_destr *destr;
++
++	AuDebugOn(!au_opt_test(au_mntflags(sb), SHWH));
++
++	err = -ENOMEM;
++	o = p = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!p))
++		goto out;
++
++	err = 0;
++	nh = whlist->nh_num;
++	memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
++	p += AUFS_WH_PFX_LEN;
++	for (u = 0; u < nh; u++) {
++		head = whlist->nh_head + u;
++		hlist_for_each_entry_safe(pos, n, head, wh_hash) {
++			destr = &pos->wh_str;
++			memcpy(p, destr->name, destr->len);
++			err = append_de(vdir, o, destr->len + AUFS_WH_PFX_LEN,
++					pos->wh_ino, pos->wh_type, delist);
++			if (unlikely(err))
++				break;
++		}
++	}
++
++	free_page((unsigned long)o);
++
++out:
++	AuTraceErr(err);
++	return err;
++#else
++	return 0;
++#endif
++}
++
++static int au_do_read_vdir(struct fillvdir_arg *arg)
++{
++	int err;
++	unsigned int rdhash;
++	loff_t offset;
++	aufs_bindex_t bend, bindex, bstart;
++	unsigned char shwh;
++	struct file *hf, *file;
++	struct super_block *sb;
++
++	file = arg->file;
++	sb = file->f_path.dentry->d_sb;
++	SiMustAnyLock(sb);
++
++	rdhash = au_sbi(sb)->si_rdhash;
++	if (!rdhash)
++		rdhash = au_rdhash_est(au_dir_size(file, /*dentry*/NULL));
++	err = au_nhash_alloc(&arg->delist, rdhash, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	err = au_nhash_alloc(&arg->whlist, rdhash, GFP_NOFS);
++	if (unlikely(err))
++		goto out_delist;
++
++	err = 0;
++	arg->flags = 0;
++	shwh = 0;
++	if (au_opt_test(au_mntflags(sb), SHWH)) {
++		shwh = 1;
++		au_fset_fillvdir(arg->flags, SHWH);
++	}
++	bstart = au_fbstart(file);
++	bend = au_fbend_dir(file);
++	for (bindex = bstart; !err && bindex <= bend; bindex++) {
++		hf = au_hf_dir(file, bindex);
++		if (!hf)
++			continue;
++
++		offset = vfsub_llseek(hf, 0, SEEK_SET);
++		err = offset;
++		if (unlikely(offset))
++			break;
++
++		arg->bindex = bindex;
++		au_fclr_fillvdir(arg->flags, WHABLE);
++		if (shwh
++		    || (bindex != bend
++			&& au_br_whable(au_sbr_perm(sb, bindex))))
++			au_fset_fillvdir(arg->flags, WHABLE);
++		do {
++			arg->err = 0;
++			au_fclr_fillvdir(arg->flags, CALLED);
++			/* smp_mb(); */
++			err = vfsub_iterate_dir(hf, &arg->ctx);
++			if (err >= 0)
++				err = arg->err;
++		} while (!err && au_ftest_fillvdir(arg->flags, CALLED));
++
++		/*
++		 * dir_relax() may be good for concurrency, but aufs should not
++		 * use it since it will cause a lockdep problem.
++		 */
++	}
++
++	if (!err && shwh)
++		err = au_handle_shwh(sb, arg->vdir, &arg->whlist, &arg->delist);
++
++	au_nhash_wh_free(&arg->whlist);
++
++out_delist:
++	au_nhash_de_free(&arg->delist);
++out:
++	return err;
++}
++
++static int read_vdir(struct file *file, int may_read)
++{
++	int err;
++	unsigned long expire;
++	unsigned char do_read;
++	struct fillvdir_arg arg = {
++		.ctx = {
++			.actor = fillvdir
++		}
++	};
++	struct inode *inode;
++	struct au_vdir *vdir, *allocated;
++
++	err = 0;
++	inode = file_inode(file);
++	IMustLock(inode);
++	SiMustAnyLock(inode->i_sb);
++
++	allocated = NULL;
++	do_read = 0;
++	expire = au_sbi(inode->i_sb)->si_rdcache;
++	vdir = au_ivdir(inode);
++	if (!vdir) {
++		do_read = 1;
++		vdir = alloc_vdir(file);
++		err = PTR_ERR(vdir);
++		if (IS_ERR(vdir))
++			goto out;
++		err = 0;
++		allocated = vdir;
++	} else if (may_read
++		   && (inode->i_version != vdir->vd_version
++		       || time_after(jiffies, vdir->vd_jiffy + expire))) {
++		do_read = 1;
++		err = reinit_vdir(vdir);
++		if (unlikely(err))
++			goto out;
++	}
++
++	if (!do_read)
++		return 0; /* success */
++
++	arg.file = file;
++	arg.vdir = vdir;
++	err = au_do_read_vdir(&arg);
++	if (!err) {
++		/* file->f_pos = 0; */ /* todo: ctx->pos? */
++		vdir->vd_version = inode->i_version;
++		vdir->vd_last.ul = 0;
++		vdir->vd_last.p.deblk = vdir->vd_deblk[0];
++		if (allocated)
++			au_set_ivdir(inode, allocated);
++	} else if (allocated)
++		au_vdir_free(allocated);
++
++out:
++	return err;
++}
++
++static int copy_vdir(struct au_vdir *tgt, struct au_vdir *src)
++{
++	int err, rerr;
++	unsigned long ul, n;
++	const unsigned int deblk_sz = src->vd_deblk_sz;
++
++	AuDebugOn(tgt->vd_nblk != 1);
++
++	err = -ENOMEM;
++	if (tgt->vd_nblk < src->vd_nblk) {
++		unsigned char **p;
++
++		p = krealloc(tgt->vd_deblk, sizeof(*p) * src->vd_nblk,
++			     GFP_NOFS);
++		if (unlikely(!p))
++			goto out;
++		tgt->vd_deblk = p;
++	}
++
++	if (tgt->vd_deblk_sz != deblk_sz) {
++		unsigned char *p;
++
++		tgt->vd_deblk_sz = deblk_sz;
++		p = krealloc(tgt->vd_deblk[0], deblk_sz, GFP_NOFS);
++		if (unlikely(!p))
++			goto out;
++		tgt->vd_deblk[0] = p;
++	}
++	memcpy(tgt->vd_deblk[0], src->vd_deblk[0], deblk_sz);
++	tgt->vd_version = src->vd_version;
++	tgt->vd_jiffy = src->vd_jiffy;
++
++	n = src->vd_nblk;
++	for (ul = 1; ul < n; ul++) {
++		tgt->vd_deblk[ul] = kmemdup(src->vd_deblk[ul], deblk_sz,
++					    GFP_NOFS);
++		if (unlikely(!tgt->vd_deblk[ul]))
++			goto out;
++		tgt->vd_nblk++;
++	}
++	tgt->vd_nblk = n;
++	tgt->vd_last.ul = tgt->vd_last.ul;
++	tgt->vd_last.p.deblk = tgt->vd_deblk[tgt->vd_last.ul];
++	tgt->vd_last.p.deblk += src->vd_last.p.deblk
++		- src->vd_deblk[src->vd_last.ul];
++	/* smp_mb(); */
++	return 0; /* success */
++
++out:
++	rerr = reinit_vdir(tgt);
++	BUG_ON(rerr);
++	return err;
++}
++
++int au_vdir_init(struct file *file)
++{
++	int err;
++	struct inode *inode;
++	struct au_vdir *vdir_cache, *allocated;
++
++	/* test file->f_pos here instead of ctx->pos */
++	err = read_vdir(file, !file->f_pos);
++	if (unlikely(err))
++		goto out;
++
++	allocated = NULL;
++	vdir_cache = au_fvdir_cache(file);
++	if (!vdir_cache) {
++		vdir_cache = alloc_vdir(file);
++		err = PTR_ERR(vdir_cache);
++		if (IS_ERR(vdir_cache))
++			goto out;
++		allocated = vdir_cache;
++	} else if (!file->f_pos && vdir_cache->vd_version != file->f_version) {
++		/* test file->f_pos here instead of ctx->pos */
++		err = reinit_vdir(vdir_cache);
++		if (unlikely(err))
++			goto out;
++	} else
++		return 0; /* success */
++
++	inode = file_inode(file);
++	err = copy_vdir(vdir_cache, au_ivdir(inode));
++	if (!err) {
++		file->f_version = inode->i_version;
++		if (allocated)
++			au_set_fvdir_cache(file, allocated);
++	} else if (allocated)
++		au_vdir_free(allocated);
++
++out:
++	return err;
++}
++
++static loff_t calc_offset(struct au_vdir *vdir)
++{
++	loff_t offset;
++	union au_vdir_deblk_p p;
++
++	p.deblk = vdir->vd_deblk[vdir->vd_last.ul];
++	offset = vdir->vd_last.p.deblk - p.deblk;
++	offset += vdir->vd_deblk_sz * vdir->vd_last.ul;
++	return offset;
++}
++
++/* returns true or false */
++static int seek_vdir(struct file *file, struct dir_context *ctx)
++{
++	int valid;
++	unsigned int deblk_sz;
++	unsigned long ul, n;
++	loff_t offset;
++	union au_vdir_deblk_p p, deblk_end;
++	struct au_vdir *vdir_cache;
++
++	valid = 1;
++	vdir_cache = au_fvdir_cache(file);
++	offset = calc_offset(vdir_cache);
++	AuDbg("offset %lld\n", offset);
++	if (ctx->pos == offset)
++		goto out;
++
++	vdir_cache->vd_last.ul = 0;
++	vdir_cache->vd_last.p.deblk = vdir_cache->vd_deblk[0];
++	if (!ctx->pos)
++		goto out;
++
++	valid = 0;
++	deblk_sz = vdir_cache->vd_deblk_sz;
++	ul = div64_u64(ctx->pos, deblk_sz);
++	AuDbg("ul %lu\n", ul);
++	if (ul >= vdir_cache->vd_nblk)
++		goto out;
++
++	n = vdir_cache->vd_nblk;
++	for (; ul < n; ul++) {
++		p.deblk = vdir_cache->vd_deblk[ul];
++		deblk_end.deblk = p.deblk + deblk_sz;
++		offset = ul;
++		offset *= deblk_sz;
++		while (!is_deblk_end(&p, &deblk_end) && offset < ctx->pos) {
++			unsigned int l;
++
++			l = calc_size(p.de->de_str.len);
++			offset += l;
++			p.deblk += l;
++		}
++		if (!is_deblk_end(&p, &deblk_end)) {
++			valid = 1;
++			vdir_cache->vd_last.ul = ul;
++			vdir_cache->vd_last.p = p;
++			break;
++		}
++	}
++
++out:
++	/* smp_mb(); */
++	AuTraceErr(!valid);
++	return valid;
++}
++
++int au_vdir_fill_de(struct file *file, struct dir_context *ctx)
++{
++	unsigned int l, deblk_sz;
++	union au_vdir_deblk_p deblk_end;
++	struct au_vdir *vdir_cache;
++	struct au_vdir_de *de;
++
++	vdir_cache = au_fvdir_cache(file);
++	if (!seek_vdir(file, ctx))
++		return 0;
++
++	deblk_sz = vdir_cache->vd_deblk_sz;
++	while (1) {
++		deblk_end.deblk = vdir_cache->vd_deblk[vdir_cache->vd_last.ul];
++		deblk_end.deblk += deblk_sz;
++		while (!is_deblk_end(&vdir_cache->vd_last.p, &deblk_end)) {
++			de = vdir_cache->vd_last.p.de;
++			AuDbg("%.*s, off%lld, i%lu, dt%d\n",
++			      de->de_str.len, de->de_str.name, ctx->pos,
++			      (unsigned long)de->de_ino, de->de_type);
++			if (unlikely(!dir_emit(ctx, de->de_str.name,
++					       de->de_str.len, de->de_ino,
++					       de->de_type))) {
++				/* todo: ignore the error caused by udba? */
++				/* return err; */
++				return 0;
++			}
++
++			l = calc_size(de->de_str.len);
++			vdir_cache->vd_last.p.deblk += l;
++			ctx->pos += l;
++		}
++		if (vdir_cache->vd_last.ul < vdir_cache->vd_nblk - 1) {
++			vdir_cache->vd_last.ul++;
++			vdir_cache->vd_last.p.deblk
++				= vdir_cache->vd_deblk[vdir_cache->vd_last.ul];
++			ctx->pos = deblk_sz * vdir_cache->vd_last.ul;
++			continue;
++		}
++		break;
++	}
++
++	/* smp_mb(); */
++	return 0;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/vfsub.c linux-4.0.4/fs/aufs/vfsub.c
+--- linux-4.0.4.orig/fs/aufs/vfsub.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/vfsub.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,833 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * sub-routines for VFS
++ */
++
++#include <linux/namei.h>
++#include <linux/security.h>
++#include <linux/splice.h>
++#include "aufs.h"
++
++int vfsub_update_h_iattr(struct path *h_path, int *did)
++{
++	int err;
++	struct kstat st;
++	struct super_block *h_sb;
++
++	/* for remote fs, leave work for its getattr or d_revalidate */
++	/* for bad i_attr fs, handle them in aufs_getattr() */
++	/* still some fs may acquire i_mutex. we need to skip them */
++	err = 0;
++	if (!did)
++		did = &err;
++	h_sb = h_path->dentry->d_sb;
++	*did = (!au_test_fs_remote(h_sb) && au_test_fs_refresh_iattr(h_sb));
++	if (*did)
++		err = vfs_getattr(h_path, &st);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct file *vfsub_dentry_open(struct path *path, int flags)
++{
++	struct file *file;
++
++	file = dentry_open(path, flags /* | __FMODE_NONOTIFY */,
++			   current_cred());
++	if (!IS_ERR_OR_NULL(file)
++	    && (file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
++		i_readcount_inc(path->dentry->d_inode);
++
++	return file;
++}
++
++struct file *vfsub_filp_open(const char *path, int oflags, int mode)
++{
++	struct file *file;
++
++	lockdep_off();
++	file = filp_open(path,
++			 oflags /* | __FMODE_NONOTIFY */,
++			 mode);
++	lockdep_on();
++	if (IS_ERR(file))
++		goto out;
++	vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
++
++out:
++	return file;
++}
++
++/*
++ * Ideally this function should call VFS:do_last() in order to keep all its
++ * checkings. But it is very hard for aufs to regenerate several VFS internal
++ * structure such as nameidata. This is a second (or third) best approach.
++ * cf. linux/fs/namei.c:do_last(), lookup_open() and atomic_open().
++ */
++int vfsub_atomic_open(struct inode *dir, struct dentry *dentry,
++		      struct vfsub_aopen_args *args, struct au_branch *br)
++{
++	int err;
++	struct file *file = args->file;
++	/* copied from linux/fs/namei.c:atomic_open() */
++	struct dentry *const DENTRY_NOT_SET = (void *)-1UL;
++
++	IMustLock(dir);
++	AuDebugOn(!dir->i_op->atomic_open);
++
++	err = au_br_test_oflag(args->open_flag, br);
++	if (unlikely(err))
++		goto out;
++
++	args->file->f_path.dentry = DENTRY_NOT_SET;
++	args->file->f_path.mnt = au_br_mnt(br);
++	err = dir->i_op->atomic_open(dir, dentry, file, args->open_flag,
++				     args->create_mode, args->opened);
++	if (err >= 0) {
++		/* some filesystems don't set FILE_CREATED while succeeded? */
++		if (*args->opened & FILE_CREATED)
++			fsnotify_create(dir, dentry);
++	} else
++		goto out;
++
++
++	if (!err) {
++		/* todo: call VFS:may_open() here */
++		err = open_check_o_direct(file);
++		/* todo: ima_file_check() too? */
++		if (!err && (args->open_flag & __FMODE_EXEC))
++			err = deny_write_access(file);
++		if (unlikely(err))
++			/* note that the file is created and still opened */
++			goto out;
++	}
++
++	atomic_inc(&br->br_count);
++	fsnotify_open(file);
++
++out:
++	return err;
++}
++
++int vfsub_kern_path(const char *name, unsigned int flags, struct path *path)
++{
++	int err;
++
++	err = kern_path(name, flags, path);
++	if (!err && path->dentry->d_inode)
++		vfsub_update_h_iattr(path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++struct dentry *vfsub_lookup_one_len(const char *name, struct dentry *parent,
++				    int len)
++{
++	struct path path = {
++		.mnt = NULL
++	};
++
++	/* VFS checks it too, but by WARN_ON_ONCE() */
++	IMustLock(parent->d_inode);
++
++	path.dentry = lookup_one_len(name, parent, len);
++	if (IS_ERR(path.dentry))
++		goto out;
++	if (path.dentry->d_inode)
++		vfsub_update_h_iattr(&path, /*did*/NULL); /*ignore*/
++
++out:
++	AuTraceErrPtr(path.dentry);
++	return path.dentry;
++}
++
++void vfsub_call_lkup_one(void *args)
++{
++	struct vfsub_lkup_one_args *a = args;
++	*a->errp = vfsub_lkup_one(a->name, a->parent);
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct dentry *vfsub_lock_rename(struct dentry *d1, struct au_hinode *hdir1,
++				 struct dentry *d2, struct au_hinode *hdir2)
++{
++	struct dentry *d;
++
++	lockdep_off();
++	d = lock_rename(d1, d2);
++	lockdep_on();
++	au_hn_suspend(hdir1);
++	if (hdir1 != hdir2)
++		au_hn_suspend(hdir2);
++
++	return d;
++}
++
++void vfsub_unlock_rename(struct dentry *d1, struct au_hinode *hdir1,
++			 struct dentry *d2, struct au_hinode *hdir2)
++{
++	au_hn_resume(hdir1);
++	if (hdir1 != hdir2)
++		au_hn_resume(hdir2);
++	lockdep_off();
++	unlock_rename(d1, d2);
++	lockdep_on();
++}
++
++/* ---------------------------------------------------------------------- */
++
++int vfsub_create(struct inode *dir, struct path *path, int mode, bool want_excl)
++{
++	int err;
++	struct dentry *d;
++
++	IMustLock(dir);
++
++	d = path->dentry;
++	path->dentry = d->d_parent;
++	err = security_path_mknod(path, d, mode, 0);
++	path->dentry = d;
++	if (unlikely(err))
++		goto out;
++
++	lockdep_off();
++	err = vfs_create(dir, path->dentry, mode, want_excl);
++	lockdep_on();
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++
++out:
++	return err;
++}
++
++int vfsub_symlink(struct inode *dir, struct path *path, const char *symname)
++{
++	int err;
++	struct dentry *d;
++
++	IMustLock(dir);
++
++	d = path->dentry;
++	path->dentry = d->d_parent;
++	err = security_path_symlink(path, d, symname);
++	path->dentry = d;
++	if (unlikely(err))
++		goto out;
++
++	lockdep_off();
++	err = vfs_symlink(dir, path->dentry, symname);
++	lockdep_on();
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++
++out:
++	return err;
++}
++
++int vfsub_mknod(struct inode *dir, struct path *path, int mode, dev_t dev)
++{
++	int err;
++	struct dentry *d;
++
++	IMustLock(dir);
++
++	d = path->dentry;
++	path->dentry = d->d_parent;
++	err = security_path_mknod(path, d, mode, new_encode_dev(dev));
++	path->dentry = d;
++	if (unlikely(err))
++		goto out;
++
++	lockdep_off();
++	err = vfs_mknod(dir, path->dentry, mode, dev);
++	lockdep_on();
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++
++out:
++	return err;
++}
++
++static int au_test_nlink(struct inode *inode)
++{
++	const unsigned int link_max = UINT_MAX >> 1; /* rough margin */
++
++	if (!au_test_fs_no_limit_nlink(inode->i_sb)
++	    || inode->i_nlink < link_max)
++		return 0;
++	return -EMLINK;
++}
++
++int vfsub_link(struct dentry *src_dentry, struct inode *dir, struct path *path,
++	       struct inode **delegated_inode)
++{
++	int err;
++	struct dentry *d;
++
++	IMustLock(dir);
++
++	err = au_test_nlink(src_dentry->d_inode);
++	if (unlikely(err))
++		return err;
++
++	/* we don't call may_linkat() */
++	d = path->dentry;
++	path->dentry = d->d_parent;
++	err = security_path_link(src_dentry, path, d);
++	path->dentry = d;
++	if (unlikely(err))
++		goto out;
++
++	lockdep_off();
++	err = vfs_link(src_dentry, dir, path->dentry, delegated_inode);
++	lockdep_on();
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		/* fuse has different memory inode for the same inumber */
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++			tmp.dentry = src_dentry;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++
++out:
++	return err;
++}
++
++int vfsub_rename(struct inode *src_dir, struct dentry *src_dentry,
++		 struct inode *dir, struct path *path,
++		 struct inode **delegated_inode)
++{
++	int err;
++	struct path tmp = {
++		.mnt	= path->mnt
++	};
++	struct dentry *d;
++
++	IMustLock(dir);
++	IMustLock(src_dir);
++
++	d = path->dentry;
++	path->dentry = d->d_parent;
++	tmp.dentry = src_dentry->d_parent;
++	err = security_path_rename(&tmp, src_dentry, path, d, /*flags*/0);
++	path->dentry = d;
++	if (unlikely(err))
++		goto out;
++
++	lockdep_off();
++	err = vfs_rename(src_dir, src_dentry, dir, path->dentry,
++			 delegated_inode, /*flags*/0);
++	lockdep_on();
++	if (!err) {
++		int did;
++
++		tmp.dentry = d->d_parent;
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = src_dentry;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++			tmp.dentry = src_dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++
++out:
++	return err;
++}
++
++int vfsub_mkdir(struct inode *dir, struct path *path, int mode)
++{
++	int err;
++	struct dentry *d;
++
++	IMustLock(dir);
++
++	d = path->dentry;
++	path->dentry = d->d_parent;
++	err = security_path_mkdir(path, d, mode);
++	path->dentry = d;
++	if (unlikely(err))
++		goto out;
++
++	lockdep_off();
++	err = vfs_mkdir(dir, path->dentry, mode);
++	lockdep_on();
++	if (!err) {
++		struct path tmp = *path;
++		int did;
++
++		vfsub_update_h_iattr(&tmp, &did);
++		if (did) {
++			tmp.dentry = path->dentry->d_parent;
++			vfsub_update_h_iattr(&tmp, /*did*/NULL);
++		}
++		/*ignore*/
++	}
++
++out:
++	return err;
++}
++
++int vfsub_rmdir(struct inode *dir, struct path *path)
++{
++	int err;
++	struct dentry *d;
++
++	IMustLock(dir);
++
++	d = path->dentry;
++	path->dentry = d->d_parent;
++	err = security_path_rmdir(path, d);
++	path->dentry = d;
++	if (unlikely(err))
++		goto out;
++
++	lockdep_off();
++	err = vfs_rmdir(dir, path->dentry);
++	lockdep_on();
++	if (!err) {
++		struct path tmp = {
++			.dentry	= path->dentry->d_parent,
++			.mnt	= path->mnt
++		};
++
++		vfsub_update_h_iattr(&tmp, /*did*/NULL); /*ignore*/
++	}
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* todo: support mmap_sem? */
++ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
++		     loff_t *ppos)
++{
++	ssize_t err;
++
++	lockdep_off();
++	err = vfs_read(file, ubuf, count, ppos);
++	lockdep_on();
++	if (err >= 0)
++		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++/* todo: kernel_read()? */
++ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count,
++		     loff_t *ppos)
++{
++	ssize_t err;
++	mm_segment_t oldfs;
++	union {
++		void *k;
++		char __user *u;
++	} buf;
++
++	buf.k = kbuf;
++	oldfs = get_fs();
++	set_fs(KERNEL_DS);
++	err = vfsub_read_u(file, buf.u, count, ppos);
++	set_fs(oldfs);
++	return err;
++}
++
++ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
++		      loff_t *ppos)
++{
++	ssize_t err;
++
++	lockdep_off();
++	err = vfs_write(file, ubuf, count, ppos);
++	lockdep_on();
++	if (err >= 0)
++		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count, loff_t *ppos)
++{
++	ssize_t err;
++	mm_segment_t oldfs;
++	union {
++		void *k;
++		const char __user *u;
++	} buf;
++
++	buf.k = kbuf;
++	oldfs = get_fs();
++	set_fs(KERNEL_DS);
++	err = vfsub_write_u(file, buf.u, count, ppos);
++	set_fs(oldfs);
++	return err;
++}
++
++int vfsub_flush(struct file *file, fl_owner_t id)
++{
++	int err;
++
++	err = 0;
++	if (file->f_op->flush) {
++		if (!au_test_nfs(file->f_path.dentry->d_sb))
++			err = file->f_op->flush(file, id);
++		else {
++			lockdep_off();
++			err = file->f_op->flush(file, id);
++			lockdep_on();
++		}
++		if (!err)
++			vfsub_update_h_iattr(&file->f_path, /*did*/NULL);
++		/*ignore*/
++	}
++	return err;
++}
++
++int vfsub_iterate_dir(struct file *file, struct dir_context *ctx)
++{
++	int err;
++
++	AuDbg("%pD, ctx{%pf, %llu}\n", file, ctx->actor, ctx->pos);
++
++	lockdep_off();
++	err = iterate_dir(file, ctx);
++	lockdep_on();
++	if (err >= 0)
++		vfsub_update_h_iattr(&file->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++long vfsub_splice_to(struct file *in, loff_t *ppos,
++		     struct pipe_inode_info *pipe, size_t len,
++		     unsigned int flags)
++{
++	long err;
++
++	lockdep_off();
++	err = do_splice_to(in, ppos, pipe, len, flags);
++	lockdep_on();
++	file_accessed(in);
++	if (err >= 0)
++		vfsub_update_h_iattr(&in->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
++		       loff_t *ppos, size_t len, unsigned int flags)
++{
++	long err;
++
++	lockdep_off();
++	err = do_splice_from(pipe, out, ppos, len, flags);
++	lockdep_on();
++	if (err >= 0)
++		vfsub_update_h_iattr(&out->f_path, /*did*/NULL); /*ignore*/
++	return err;
++}
++
++int vfsub_fsync(struct file *file, struct path *path, int datasync)
++{
++	int err;
++
++	/* file can be NULL */
++	lockdep_off();
++	err = vfs_fsync(file, datasync);
++	lockdep_on();
++	if (!err) {
++		if (!path) {
++			AuDebugOn(!file);
++			path = &file->f_path;
++		}
++		vfsub_update_h_iattr(path, /*did*/NULL); /*ignore*/
++	}
++	return err;
++}
++
++/* cf. open.c:do_sys_truncate() and do_sys_ftruncate() */
++int vfsub_trunc(struct path *h_path, loff_t length, unsigned int attr,
++		struct file *h_file)
++{
++	int err;
++	struct inode *h_inode;
++	struct super_block *h_sb;
++
++	if (!h_file) {
++		err = vfsub_truncate(h_path, length);
++		goto out;
++	}
++
++	h_inode = h_path->dentry->d_inode;
++	h_sb = h_inode->i_sb;
++	lockdep_off();
++	sb_start_write(h_sb);
++	lockdep_on();
++	err = locks_verify_truncate(h_inode, h_file, length);
++	if (!err)
++		err = security_path_truncate(h_path);
++	if (!err) {
++		lockdep_off();
++		err = do_truncate(h_path->dentry, length, attr, h_file);
++		lockdep_on();
++	}
++	lockdep_off();
++	sb_end_write(h_sb);
++	lockdep_on();
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_vfsub_mkdir_args {
++	int *errp;
++	struct inode *dir;
++	struct path *path;
++	int mode;
++};
++
++static void au_call_vfsub_mkdir(void *args)
++{
++	struct au_vfsub_mkdir_args *a = args;
++	*a->errp = vfsub_mkdir(a->dir, a->path, a->mode);
++}
++
++int vfsub_sio_mkdir(struct inode *dir, struct path *path, int mode)
++{
++	int err, do_sio, wkq_err;
++
++	do_sio = au_test_h_perm_sio(dir, MAY_EXEC | MAY_WRITE);
++	if (!do_sio) {
++		lockdep_off();
++		err = vfsub_mkdir(dir, path, mode);
++		lockdep_on();
++	} else {
++		struct au_vfsub_mkdir_args args = {
++			.errp	= &err,
++			.dir	= dir,
++			.path	= path,
++			.mode	= mode
++		};
++		wkq_err = au_wkq_wait(au_call_vfsub_mkdir, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
++
++struct au_vfsub_rmdir_args {
++	int *errp;
++	struct inode *dir;
++	struct path *path;
++};
++
++static void au_call_vfsub_rmdir(void *args)
++{
++	struct au_vfsub_rmdir_args *a = args;
++	*a->errp = vfsub_rmdir(a->dir, a->path);
++}
++
++int vfsub_sio_rmdir(struct inode *dir, struct path *path)
++{
++	int err, do_sio, wkq_err;
++
++	do_sio = au_test_h_perm_sio(dir, MAY_EXEC | MAY_WRITE);
++	if (!do_sio) {
++		lockdep_off();
++		err = vfsub_rmdir(dir, path);
++		lockdep_on();
++	} else {
++		struct au_vfsub_rmdir_args args = {
++			.errp	= &err,
++			.dir	= dir,
++			.path	= path
++		};
++		wkq_err = au_wkq_wait(au_call_vfsub_rmdir, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct notify_change_args {
++	int *errp;
++	struct path *path;
++	struct iattr *ia;
++	struct inode **delegated_inode;
++};
++
++static void call_notify_change(void *args)
++{
++	struct notify_change_args *a = args;
++	struct inode *h_inode;
++
++	h_inode = a->path->dentry->d_inode;
++	IMustLock(h_inode);
++
++	*a->errp = -EPERM;
++	if (!IS_IMMUTABLE(h_inode) && !IS_APPEND(h_inode)) {
++		lockdep_off();
++		*a->errp = notify_change(a->path->dentry, a->ia,
++					 a->delegated_inode);
++		lockdep_on();
++		if (!*a->errp)
++			vfsub_update_h_iattr(a->path, /*did*/NULL); /*ignore*/
++	}
++	AuTraceErr(*a->errp);
++}
++
++int vfsub_notify_change(struct path *path, struct iattr *ia,
++			struct inode **delegated_inode)
++{
++	int err;
++	struct notify_change_args args = {
++		.errp			= &err,
++		.path			= path,
++		.ia			= ia,
++		.delegated_inode	= delegated_inode
++	};
++
++	call_notify_change(&args);
++
++	return err;
++}
++
++int vfsub_sio_notify_change(struct path *path, struct iattr *ia,
++			    struct inode **delegated_inode)
++{
++	int err, wkq_err;
++	struct notify_change_args args = {
++		.errp			= &err,
++		.path			= path,
++		.ia			= ia,
++		.delegated_inode	= delegated_inode
++	};
++
++	wkq_err = au_wkq_wait(call_notify_change, &args);
++	if (unlikely(wkq_err))
++		err = wkq_err;
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct unlink_args {
++	int *errp;
++	struct inode *dir;
++	struct path *path;
++	struct inode **delegated_inode;
++};
++
++static void call_unlink(void *args)
++{
++	struct unlink_args *a = args;
++	struct dentry *d = a->path->dentry;
++	struct inode *h_inode;
++	const int stop_sillyrename = (au_test_nfs(d->d_sb)
++				      && au_dcount(d) == 1);
++
++	IMustLock(a->dir);
++
++	a->path->dentry = d->d_parent;
++	*a->errp = security_path_unlink(a->path, d);
++	a->path->dentry = d;
++	if (unlikely(*a->errp))
++		return;
++
++	if (!stop_sillyrename)
++		dget(d);
++	h_inode = d->d_inode;
++	if (h_inode)
++		ihold(h_inode);
++
++	lockdep_off();
++	*a->errp = vfs_unlink(a->dir, d, a->delegated_inode);
++	lockdep_on();
++	if (!*a->errp) {
++		struct path tmp = {
++			.dentry = d->d_parent,
++			.mnt	= a->path->mnt
++		};
++		vfsub_update_h_iattr(&tmp, /*did*/NULL); /*ignore*/
++	}
++
++	if (!stop_sillyrename)
++		dput(d);
++	if (h_inode)
++		iput(h_inode);
++
++	AuTraceErr(*a->errp);
++}
++
++/*
++ * @dir: must be locked.
++ * @dentry: target dentry.
++ */
++int vfsub_unlink(struct inode *dir, struct path *path,
++		 struct inode **delegated_inode, int force)
++{
++	int err;
++	struct unlink_args args = {
++		.errp			= &err,
++		.dir			= dir,
++		.path			= path,
++		.delegated_inode	= delegated_inode
++	};
++
++	if (!force)
++		call_unlink(&args);
++	else {
++		int wkq_err;
++
++		wkq_err = au_wkq_wait(call_unlink, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/vfsub.h linux-4.0.4/fs/aufs/vfsub.h
+--- linux-4.0.4.orig/fs/aufs/vfsub.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/vfsub.h	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,273 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * sub-routines for VFS
++ */
++
++#ifndef __AUFS_VFSUB_H__
++#define __AUFS_VFSUB_H__
++
++#ifdef __KERNEL__
++
++#include <linux/fs.h>
++#include <linux/mount.h>
++#include <linux/xattr.h>
++#include "debug.h"
++
++/* copied from linux/fs/internal.h */
++/* todo: BAD approach!! */
++extern void __mnt_drop_write(struct vfsmount *);
++extern spinlock_t inode_sb_list_lock;
++extern int open_check_o_direct(struct file *f);
++
++/* ---------------------------------------------------------------------- */
++
++/* lock subclass for lower inode */
++/* default MAX_LOCKDEP_SUBCLASSES(8) is not enough */
++/* reduce? gave up. */
++enum {
++	AuLsc_I_Begin = I_MUTEX_PARENT2, /* 5 */
++	AuLsc_I_PARENT,		/* lower inode, parent first */
++	AuLsc_I_PARENT2,	/* copyup dirs */
++	AuLsc_I_PARENT3,	/* copyup wh */
++	AuLsc_I_CHILD,
++	AuLsc_I_CHILD2,
++	AuLsc_I_End
++};
++
++/* to debug easier, do not make them inlined functions */
++#define MtxMustLock(mtx)	AuDebugOn(!mutex_is_locked(mtx))
++#define IMustLock(i)		MtxMustLock(&(i)->i_mutex)
++
++/* ---------------------------------------------------------------------- */
++
++static inline void vfsub_drop_nlink(struct inode *inode)
++{
++	AuDebugOn(!inode->i_nlink);
++	drop_nlink(inode);
++}
++
++static inline void vfsub_dead_dir(struct inode *inode)
++{
++	AuDebugOn(!S_ISDIR(inode->i_mode));
++	inode->i_flags |= S_DEAD;
++	clear_nlink(inode);
++}
++
++static inline int vfsub_native_ro(struct inode *inode)
++{
++	return (inode->i_sb->s_flags & MS_RDONLY)
++		|| IS_RDONLY(inode)
++		/* || IS_APPEND(inode) */
++		|| IS_IMMUTABLE(inode);
++}
++
++/* ---------------------------------------------------------------------- */
++
++int vfsub_update_h_iattr(struct path *h_path, int *did);
++struct file *vfsub_dentry_open(struct path *path, int flags);
++struct file *vfsub_filp_open(const char *path, int oflags, int mode);
++struct vfsub_aopen_args {
++	struct file	*file;
++	unsigned int	open_flag;
++	umode_t		create_mode;
++	int		*opened;
++};
++struct au_branch;
++int vfsub_atomic_open(struct inode *dir, struct dentry *dentry,
++		      struct vfsub_aopen_args *args, struct au_branch *br);
++int vfsub_kern_path(const char *name, unsigned int flags, struct path *path);
++
++struct dentry *vfsub_lookup_one_len(const char *name, struct dentry *parent,
++				    int len);
++
++struct vfsub_lkup_one_args {
++	struct dentry **errp;
++	struct qstr *name;
++	struct dentry *parent;
++};
++
++static inline struct dentry *vfsub_lkup_one(struct qstr *name,
++					    struct dentry *parent)
++{
++	return vfsub_lookup_one_len(name->name, parent, name->len);
++}
++
++void vfsub_call_lkup_one(void *args);
++
++/* ---------------------------------------------------------------------- */
++
++static inline int vfsub_mnt_want_write(struct vfsmount *mnt)
++{
++	int err;
++
++	lockdep_off();
++	err = mnt_want_write(mnt);
++	lockdep_on();
++	return err;
++}
++
++static inline void vfsub_mnt_drop_write(struct vfsmount *mnt)
++{
++	lockdep_off();
++	mnt_drop_write(mnt);
++	lockdep_on();
++}
++
++#if 0 /* reserved */
++static inline void vfsub_mnt_drop_write_file(struct file *file)
++{
++	lockdep_off();
++	mnt_drop_write_file(file);
++	lockdep_on();
++}
++#endif
++
++/* ---------------------------------------------------------------------- */
++
++struct au_hinode;
++struct dentry *vfsub_lock_rename(struct dentry *d1, struct au_hinode *hdir1,
++				 struct dentry *d2, struct au_hinode *hdir2);
++void vfsub_unlock_rename(struct dentry *d1, struct au_hinode *hdir1,
++			 struct dentry *d2, struct au_hinode *hdir2);
++
++int vfsub_create(struct inode *dir, struct path *path, int mode,
++		 bool want_excl);
++int vfsub_symlink(struct inode *dir, struct path *path,
++		  const char *symname);
++int vfsub_mknod(struct inode *dir, struct path *path, int mode, dev_t dev);
++int vfsub_link(struct dentry *src_dentry, struct inode *dir,
++	       struct path *path, struct inode **delegated_inode);
++int vfsub_rename(struct inode *src_hdir, struct dentry *src_dentry,
++		 struct inode *hdir, struct path *path,
++		 struct inode **delegated_inode);
++int vfsub_mkdir(struct inode *dir, struct path *path, int mode);
++int vfsub_rmdir(struct inode *dir, struct path *path);
++
++/* ---------------------------------------------------------------------- */
++
++ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
++		     loff_t *ppos);
++ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count,
++			loff_t *ppos);
++ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
++		      loff_t *ppos);
++ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count,
++		      loff_t *ppos);
++int vfsub_flush(struct file *file, fl_owner_t id);
++int vfsub_iterate_dir(struct file *file, struct dir_context *ctx);
++
++static inline loff_t vfsub_f_size_read(struct file *file)
++{
++	return i_size_read(file_inode(file));
++}
++
++static inline unsigned int vfsub_file_flags(struct file *file)
++{
++	unsigned int flags;
++
++	spin_lock(&file->f_lock);
++	flags = file->f_flags;
++	spin_unlock(&file->f_lock);
++
++	return flags;
++}
++
++#if 0 /* reserved */
++static inline void vfsub_file_accessed(struct file *h_file)
++{
++	file_accessed(h_file);
++	vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL); /*ignore*/
++}
++#endif
++
++static inline void vfsub_touch_atime(struct vfsmount *h_mnt,
++				     struct dentry *h_dentry)
++{
++	struct path h_path = {
++		.dentry	= h_dentry,
++		.mnt	= h_mnt
++	};
++	touch_atime(&h_path);
++	vfsub_update_h_iattr(&h_path, /*did*/NULL); /*ignore*/
++}
++
++static inline int vfsub_update_time(struct inode *h_inode, struct timespec *ts,
++				    int flags)
++{
++	return generic_update_time(h_inode, ts, flags);
++	/* no vfsub_update_h_iattr() since we don't have struct path */
++}
++
++long vfsub_splice_to(struct file *in, loff_t *ppos,
++		     struct pipe_inode_info *pipe, size_t len,
++		     unsigned int flags);
++long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
++		       loff_t *ppos, size_t len, unsigned int flags);
++
++static inline long vfsub_truncate(struct path *path, loff_t length)
++{
++	long err;
++
++	lockdep_off();
++	err = vfs_truncate(path, length);
++	lockdep_on();
++	return err;
++}
++
++int vfsub_trunc(struct path *h_path, loff_t length, unsigned int attr,
++		struct file *h_file);
++int vfsub_fsync(struct file *file, struct path *path, int datasync);
++
++/* ---------------------------------------------------------------------- */
++
++static inline loff_t vfsub_llseek(struct file *file, loff_t offset, int origin)
++{
++	loff_t err;
++
++	lockdep_off();
++	err = vfs_llseek(file, offset, origin);
++	lockdep_on();
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int vfsub_sio_mkdir(struct inode *dir, struct path *path, int mode);
++int vfsub_sio_rmdir(struct inode *dir, struct path *path);
++int vfsub_sio_notify_change(struct path *path, struct iattr *ia,
++			    struct inode **delegated_inode);
++int vfsub_notify_change(struct path *path, struct iattr *ia,
++			struct inode **delegated_inode);
++int vfsub_unlink(struct inode *dir, struct path *path,
++		 struct inode **delegated_inode, int force);
++
++/* ---------------------------------------------------------------------- */
++
++static inline int vfsub_setxattr(struct dentry *dentry, const char *name,
++				 const void *value, size_t size, int flags)
++{
++	int err;
++
++	lockdep_off();
++	err = vfs_setxattr(dentry, name, value, size, flags);
++	lockdep_on();
++
++	return err;
++}
++
++static inline int vfsub_removexattr(struct dentry *dentry, const char *name)
++{
++	int err;
++
++	lockdep_off();
++	err = vfs_removexattr(dentry, name);
++	lockdep_on();
++
++	return err;
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_VFSUB_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/wbr_policy.c linux-4.0.4/fs/aufs/wbr_policy.c
+--- linux-4.0.4.orig/fs/aufs/wbr_policy.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/wbr_policy.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,752 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * policies for selecting one among multiple writable branches
++ */
++
++#include <linux/statfs.h>
++#include "aufs.h"
++
++/* subset of cpup_attr() */
++static noinline_for_stack
++int au_cpdown_attr(struct path *h_path, struct dentry *h_src)
++{
++	int err, sbits;
++	struct iattr ia;
++	struct inode *h_isrc;
++
++	h_isrc = h_src->d_inode;
++	ia.ia_valid = ATTR_FORCE | ATTR_MODE | ATTR_UID | ATTR_GID;
++	ia.ia_mode = h_isrc->i_mode;
++	ia.ia_uid = h_isrc->i_uid;
++	ia.ia_gid = h_isrc->i_gid;
++	sbits = !!(ia.ia_mode & (S_ISUID | S_ISGID));
++	au_cpup_attr_flags(h_path->dentry->d_inode, h_isrc->i_flags);
++	/* no delegation since it is just created */
++	err = vfsub_sio_notify_change(h_path, &ia, /*delegated*/NULL);
++
++	/* is this nfs only? */
++	if (!err && sbits && au_test_nfs(h_path->dentry->d_sb)) {
++		ia.ia_valid = ATTR_FORCE | ATTR_MODE;
++		ia.ia_mode = h_isrc->i_mode;
++		err = vfsub_sio_notify_change(h_path, &ia, /*delegated*/NULL);
++	}
++
++	return err;
++}
++
++#define AuCpdown_PARENT_OPQ	1
++#define AuCpdown_WHED		(1 << 1)
++#define AuCpdown_MADE_DIR	(1 << 2)
++#define AuCpdown_DIROPQ		(1 << 3)
++#define au_ftest_cpdown(flags, name)	((flags) & AuCpdown_##name)
++#define au_fset_cpdown(flags, name) \
++	do { (flags) |= AuCpdown_##name; } while (0)
++#define au_fclr_cpdown(flags, name) \
++	do { (flags) &= ~AuCpdown_##name; } while (0)
++
++static int au_cpdown_dir_opq(struct dentry *dentry, aufs_bindex_t bdst,
++			     unsigned int *flags)
++{
++	int err;
++	struct dentry *opq_dentry;
++
++	opq_dentry = au_diropq_create(dentry, bdst);
++	err = PTR_ERR(opq_dentry);
++	if (IS_ERR(opq_dentry))
++		goto out;
++	dput(opq_dentry);
++	au_fset_cpdown(*flags, DIROPQ);
++
++out:
++	return err;
++}
++
++static int au_cpdown_dir_wh(struct dentry *dentry, struct dentry *h_parent,
++			    struct inode *dir, aufs_bindex_t bdst)
++{
++	int err;
++	struct path h_path;
++	struct au_branch *br;
++
++	br = au_sbr(dentry->d_sb, bdst);
++	h_path.dentry = au_wh_lkup(h_parent, &dentry->d_name, br);
++	err = PTR_ERR(h_path.dentry);
++	if (IS_ERR(h_path.dentry))
++		goto out;
++
++	err = 0;
++	if (h_path.dentry->d_inode) {
++		h_path.mnt = au_br_mnt(br);
++		err = au_wh_unlink_dentry(au_h_iptr(dir, bdst), &h_path,
++					  dentry);
++	}
++	dput(h_path.dentry);
++
++out:
++	return err;
++}
++
++static int au_cpdown_dir(struct dentry *dentry, aufs_bindex_t bdst,
++			 struct au_pin *pin,
++			 struct dentry *h_parent, void *arg)
++{
++	int err, rerr;
++	aufs_bindex_t bopq, bstart;
++	struct path h_path;
++	struct dentry *parent;
++	struct inode *h_dir, *h_inode, *inode, *dir;
++	unsigned int *flags = arg;
++
++	bstart = au_dbstart(dentry);
++	/* dentry is di-locked */
++	parent = dget_parent(dentry);
++	dir = parent->d_inode;
++	h_dir = h_parent->d_inode;
++	AuDebugOn(h_dir != au_h_iptr(dir, bdst));
++	IMustLock(h_dir);
++
++	err = au_lkup_neg(dentry, bdst, /*wh*/0);
++	if (unlikely(err < 0))
++		goto out;
++	h_path.dentry = au_h_dptr(dentry, bdst);
++	h_path.mnt = au_sbr_mnt(dentry->d_sb, bdst);
++	err = vfsub_sio_mkdir(au_h_iptr(dir, bdst), &h_path,
++			      S_IRWXU | S_IRUGO | S_IXUGO);
++	if (unlikely(err))
++		goto out_put;
++	au_fset_cpdown(*flags, MADE_DIR);
++
++	bopq = au_dbdiropq(dentry);
++	au_fclr_cpdown(*flags, WHED);
++	au_fclr_cpdown(*flags, DIROPQ);
++	if (au_dbwh(dentry) == bdst)
++		au_fset_cpdown(*flags, WHED);
++	if (!au_ftest_cpdown(*flags, PARENT_OPQ) && bopq <= bdst)
++		au_fset_cpdown(*flags, PARENT_OPQ);
++	h_inode = h_path.dentry->d_inode;
++	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++	if (au_ftest_cpdown(*flags, WHED)) {
++		err = au_cpdown_dir_opq(dentry, bdst, flags);
++		if (unlikely(err)) {
++			mutex_unlock(&h_inode->i_mutex);
++			goto out_dir;
++		}
++	}
++
++	err = au_cpdown_attr(&h_path, au_h_dptr(dentry, bstart));
++	mutex_unlock(&h_inode->i_mutex);
++	if (unlikely(err))
++		goto out_opq;
++
++	if (au_ftest_cpdown(*flags, WHED)) {
++		err = au_cpdown_dir_wh(dentry, h_parent, dir, bdst);
++		if (unlikely(err))
++			goto out_opq;
++	}
++
++	inode = dentry->d_inode;
++	if (au_ibend(inode) < bdst)
++		au_set_ibend(inode, bdst);
++	au_set_h_iptr(inode, bdst, au_igrab(h_inode),
++		      au_hi_flags(inode, /*isdir*/1));
++	au_fhsm_wrote(dentry->d_sb, bdst, /*force*/0);
++	goto out; /* success */
++
++	/* revert */
++out_opq:
++	if (au_ftest_cpdown(*flags, DIROPQ)) {
++		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
++		rerr = au_diropq_remove(dentry, bdst);
++		mutex_unlock(&h_inode->i_mutex);
++		if (unlikely(rerr)) {
++			AuIOErr("failed removing diropq for %pd b%d (%d)\n",
++				dentry, bdst, rerr);
++			err = -EIO;
++			goto out;
++		}
++	}
++out_dir:
++	if (au_ftest_cpdown(*flags, MADE_DIR)) {
++		rerr = vfsub_sio_rmdir(au_h_iptr(dir, bdst), &h_path);
++		if (unlikely(rerr)) {
++			AuIOErr("failed removing %pd b%d (%d)\n",
++				dentry, bdst, rerr);
++			err = -EIO;
++		}
++	}
++out_put:
++	au_set_h_dptr(dentry, bdst, NULL);
++	if (au_dbend(dentry) == bdst)
++		au_update_dbend(dentry);
++out:
++	dput(parent);
++	return err;
++}
++
++int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst)
++{
++	int err;
++	unsigned int flags;
++
++	flags = 0;
++	err = au_cp_dirs(dentry, bdst, au_cpdown_dir, &flags);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* policies for create */
++
++int au_wbr_nonopq(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	int err, i, j, ndentry;
++	aufs_bindex_t bopq;
++	struct au_dcsub_pages dpages;
++	struct au_dpage *dpage;
++	struct dentry **dentries, *parent, *d;
++
++	err = au_dpages_init(&dpages, GFP_NOFS);
++	if (unlikely(err))
++		goto out;
++	parent = dget_parent(dentry);
++	err = au_dcsub_pages_rev_aufs(&dpages, parent, /*do_include*/0);
++	if (unlikely(err))
++		goto out_free;
++
++	err = bindex;
++	for (i = 0; i < dpages.ndpage; i++) {
++		dpage = dpages.dpages + i;
++		dentries = dpage->dentries;
++		ndentry = dpage->ndentry;
++		for (j = 0; j < ndentry; j++) {
++			d = dentries[j];
++			di_read_lock_parent2(d, !AuLock_IR);
++			bopq = au_dbdiropq(d);
++			di_read_unlock(d, !AuLock_IR);
++			if (bopq >= 0 && bopq < err)
++				err = bopq;
++		}
++	}
++
++out_free:
++	dput(parent);
++	au_dpages_free(&dpages);
++out:
++	return err;
++}
++
++static int au_wbr_bu(struct super_block *sb, aufs_bindex_t bindex)
++{
++	for (; bindex >= 0; bindex--)
++		if (!au_br_rdonly(au_sbr(sb, bindex)))
++			return bindex;
++	return -EROFS;
++}
++
++/* top down parent */
++static int au_wbr_create_tdp(struct dentry *dentry,
++			     unsigned int flags __maybe_unused)
++{
++	int err;
++	aufs_bindex_t bstart, bindex;
++	struct super_block *sb;
++	struct dentry *parent, *h_parent;
++
++	sb = dentry->d_sb;
++	bstart = au_dbstart(dentry);
++	err = bstart;
++	if (!au_br_rdonly(au_sbr(sb, bstart)))
++		goto out;
++
++	err = -EROFS;
++	parent = dget_parent(dentry);
++	for (bindex = au_dbstart(parent); bindex < bstart; bindex++) {
++		h_parent = au_h_dptr(parent, bindex);
++		if (!h_parent || !h_parent->d_inode)
++			continue;
++
++		if (!au_br_rdonly(au_sbr(sb, bindex))) {
++			err = bindex;
++			break;
++		}
++	}
++	dput(parent);
++
++	/* bottom up here */
++	if (unlikely(err < 0)) {
++		err = au_wbr_bu(sb, bstart - 1);
++		if (err >= 0)
++			err = au_wbr_nonopq(dentry, err);
++	}
++
++out:
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* an exception for the policy other than tdp */
++static int au_wbr_create_exp(struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bwh, bdiropq;
++	struct dentry *parent;
++
++	err = -1;
++	bwh = au_dbwh(dentry);
++	parent = dget_parent(dentry);
++	bdiropq = au_dbdiropq(parent);
++	if (bwh >= 0) {
++		if (bdiropq >= 0)
++			err = min(bdiropq, bwh);
++		else
++			err = bwh;
++		AuDbg("%d\n", err);
++	} else if (bdiropq >= 0) {
++		err = bdiropq;
++		AuDbg("%d\n", err);
++	}
++	dput(parent);
++
++	if (err >= 0)
++		err = au_wbr_nonopq(dentry, err);
++
++	if (err >= 0 && au_br_rdonly(au_sbr(dentry->d_sb, err)))
++		err = -1;
++
++	AuDbg("%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* round robin */
++static int au_wbr_create_init_rr(struct super_block *sb)
++{
++	int err;
++
++	err = au_wbr_bu(sb, au_sbend(sb));
++	atomic_set(&au_sbi(sb)->si_wbr_rr_next, -err); /* less important */
++	/* smp_mb(); */
++
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++static int au_wbr_create_rr(struct dentry *dentry, unsigned int flags)
++{
++	int err, nbr;
++	unsigned int u;
++	aufs_bindex_t bindex, bend;
++	struct super_block *sb;
++	atomic_t *next;
++
++	err = au_wbr_create_exp(dentry);
++	if (err >= 0)
++		goto out;
++
++	sb = dentry->d_sb;
++	next = &au_sbi(sb)->si_wbr_rr_next;
++	bend = au_sbend(sb);
++	nbr = bend + 1;
++	for (bindex = 0; bindex <= bend; bindex++) {
++		if (!au_ftest_wbr(flags, DIR)) {
++			err = atomic_dec_return(next) + 1;
++			/* modulo for 0 is meaningless */
++			if (unlikely(!err))
++				err = atomic_dec_return(next) + 1;
++		} else
++			err = atomic_read(next);
++		AuDbg("%d\n", err);
++		u = err;
++		err = u % nbr;
++		AuDbg("%d\n", err);
++		if (!au_br_rdonly(au_sbr(sb, err)))
++			break;
++		err = -EROFS;
++	}
++
++	if (err >= 0)
++		err = au_wbr_nonopq(dentry, err);
++
++out:
++	AuDbg("%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* most free space */
++static void au_mfs(struct dentry *dentry, struct dentry *parent)
++{
++	struct super_block *sb;
++	struct au_branch *br;
++	struct au_wbr_mfs *mfs;
++	struct dentry *h_parent;
++	aufs_bindex_t bindex, bend;
++	int err;
++	unsigned long long b, bavail;
++	struct path h_path;
++	/* reduce the stack usage */
++	struct kstatfs *st;
++
++	st = kmalloc(sizeof(*st), GFP_NOFS);
++	if (unlikely(!st)) {
++		AuWarn1("failed updating mfs(%d), ignored\n", -ENOMEM);
++		return;
++	}
++
++	bavail = 0;
++	sb = dentry->d_sb;
++	mfs = &au_sbi(sb)->si_wbr_mfs;
++	MtxMustLock(&mfs->mfs_lock);
++	mfs->mfs_bindex = -EROFS;
++	mfs->mfsrr_bytes = 0;
++	if (!parent) {
++		bindex = 0;
++		bend = au_sbend(sb);
++	} else {
++		bindex = au_dbstart(parent);
++		bend = au_dbtaildir(parent);
++	}
++
++	for (; bindex <= bend; bindex++) {
++		if (parent) {
++			h_parent = au_h_dptr(parent, bindex);
++			if (!h_parent || !h_parent->d_inode)
++				continue;
++		}
++		br = au_sbr(sb, bindex);
++		if (au_br_rdonly(br))
++			continue;
++
++		/* sb->s_root for NFS is unreliable */
++		h_path.mnt = au_br_mnt(br);
++		h_path.dentry = h_path.mnt->mnt_root;
++		err = vfs_statfs(&h_path, st);
++		if (unlikely(err)) {
++			AuWarn1("failed statfs, b%d, %d\n", bindex, err);
++			continue;
++		}
++
++		/* when the available size is equal, select the lower one */
++		BUILD_BUG_ON(sizeof(b) < sizeof(st->f_bavail)
++			     || sizeof(b) < sizeof(st->f_bsize));
++		b = st->f_bavail * st->f_bsize;
++		br->br_wbr->wbr_bytes = b;
++		if (b >= bavail) {
++			bavail = b;
++			mfs->mfs_bindex = bindex;
++			mfs->mfs_jiffy = jiffies;
++		}
++	}
++
++	mfs->mfsrr_bytes = bavail;
++	AuDbg("b%d\n", mfs->mfs_bindex);
++	kfree(st);
++}
++
++static int au_wbr_create_mfs(struct dentry *dentry, unsigned int flags)
++{
++	int err;
++	struct dentry *parent;
++	struct super_block *sb;
++	struct au_wbr_mfs *mfs;
++
++	err = au_wbr_create_exp(dentry);
++	if (err >= 0)
++		goto out;
++
++	sb = dentry->d_sb;
++	parent = NULL;
++	if (au_ftest_wbr(flags, PARENT))
++		parent = dget_parent(dentry);
++	mfs = &au_sbi(sb)->si_wbr_mfs;
++	mutex_lock(&mfs->mfs_lock);
++	if (time_after(jiffies, mfs->mfs_jiffy + mfs->mfs_expire)
++	    || mfs->mfs_bindex < 0
++	    || au_br_rdonly(au_sbr(sb, mfs->mfs_bindex)))
++		au_mfs(dentry, parent);
++	mutex_unlock(&mfs->mfs_lock);
++	err = mfs->mfs_bindex;
++	dput(parent);
++
++	if (err >= 0)
++		err = au_wbr_nonopq(dentry, err);
++
++out:
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++static int au_wbr_create_init_mfs(struct super_block *sb)
++{
++	struct au_wbr_mfs *mfs;
++
++	mfs = &au_sbi(sb)->si_wbr_mfs;
++	mutex_init(&mfs->mfs_lock);
++	mfs->mfs_jiffy = 0;
++	mfs->mfs_bindex = -EROFS;
++
++	return 0;
++}
++
++static int au_wbr_create_fin_mfs(struct super_block *sb __maybe_unused)
++{
++	mutex_destroy(&au_sbi(sb)->si_wbr_mfs.mfs_lock);
++	return 0;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* most free space and then round robin */
++static int au_wbr_create_mfsrr(struct dentry *dentry, unsigned int flags)
++{
++	int err;
++	struct au_wbr_mfs *mfs;
++
++	err = au_wbr_create_mfs(dentry, flags);
++	if (err >= 0) {
++		mfs = &au_sbi(dentry->d_sb)->si_wbr_mfs;
++		mutex_lock(&mfs->mfs_lock);
++		if (mfs->mfsrr_bytes < mfs->mfsrr_watermark)
++			err = au_wbr_create_rr(dentry, flags);
++		mutex_unlock(&mfs->mfs_lock);
++	}
++
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++static int au_wbr_create_init_mfsrr(struct super_block *sb)
++{
++	int err;
++
++	au_wbr_create_init_mfs(sb); /* ignore */
++	err = au_wbr_create_init_rr(sb);
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* top down parent and most free space */
++static int au_wbr_create_pmfs(struct dentry *dentry, unsigned int flags)
++{
++	int err, e2;
++	unsigned long long b;
++	aufs_bindex_t bindex, bstart, bend;
++	struct super_block *sb;
++	struct dentry *parent, *h_parent;
++	struct au_branch *br;
++
++	err = au_wbr_create_tdp(dentry, flags);
++	if (unlikely(err < 0))
++		goto out;
++	parent = dget_parent(dentry);
++	bstart = au_dbstart(parent);
++	bend = au_dbtaildir(parent);
++	if (bstart == bend)
++		goto out_parent; /* success */
++
++	e2 = au_wbr_create_mfs(dentry, flags);
++	if (e2 < 0)
++		goto out_parent; /* success */
++
++	/* when the available size is equal, select upper one */
++	sb = dentry->d_sb;
++	br = au_sbr(sb, err);
++	b = br->br_wbr->wbr_bytes;
++	AuDbg("b%d, %llu\n", err, b);
++
++	for (bindex = bstart; bindex <= bend; bindex++) {
++		h_parent = au_h_dptr(parent, bindex);
++		if (!h_parent || !h_parent->d_inode)
++			continue;
++
++		br = au_sbr(sb, bindex);
++		if (!au_br_rdonly(br) && br->br_wbr->wbr_bytes > b) {
++			b = br->br_wbr->wbr_bytes;
++			err = bindex;
++			AuDbg("b%d, %llu\n", err, b);
++		}
++	}
++
++	if (err >= 0)
++		err = au_wbr_nonopq(dentry, err);
++
++out_parent:
++	dput(parent);
++out:
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * - top down parent
++ * - most free space with parent
++ * - most free space round-robin regardless parent
++ */
++static int au_wbr_create_pmfsrr(struct dentry *dentry, unsigned int flags)
++{
++	int err;
++	unsigned long long watermark;
++	struct super_block *sb;
++	struct au_branch *br;
++	struct au_wbr_mfs *mfs;
++
++	err = au_wbr_create_pmfs(dentry, flags | AuWbr_PARENT);
++	if (unlikely(err < 0))
++		goto out;
++
++	sb = dentry->d_sb;
++	br = au_sbr(sb, err);
++	mfs = &au_sbi(sb)->si_wbr_mfs;
++	mutex_lock(&mfs->mfs_lock);
++	watermark = mfs->mfsrr_watermark;
++	mutex_unlock(&mfs->mfs_lock);
++	if (br->br_wbr->wbr_bytes < watermark)
++		/* regardless the parent dir */
++		err = au_wbr_create_mfsrr(dentry, flags);
++
++out:
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* policies for copyup */
++
++/* top down parent */
++static int au_wbr_copyup_tdp(struct dentry *dentry)
++{
++	return au_wbr_create_tdp(dentry, /*flags, anything is ok*/0);
++}
++
++/* bottom up parent */
++static int au_wbr_copyup_bup(struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bindex, bstart;
++	struct dentry *parent, *h_parent;
++	struct super_block *sb;
++
++	err = -EROFS;
++	sb = dentry->d_sb;
++	parent = dget_parent(dentry);
++	bstart = au_dbstart(parent);
++	for (bindex = au_dbstart(dentry); bindex >= bstart; bindex--) {
++		h_parent = au_h_dptr(parent, bindex);
++		if (!h_parent || !h_parent->d_inode)
++			continue;
++
++		if (!au_br_rdonly(au_sbr(sb, bindex))) {
++			err = bindex;
++			break;
++		}
++	}
++	dput(parent);
++
++	/* bottom up here */
++	if (unlikely(err < 0))
++		err = au_wbr_bu(sb, bstart - 1);
++
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++/* bottom up */
++int au_wbr_do_copyup_bu(struct dentry *dentry, aufs_bindex_t bstart)
++{
++	int err;
++
++	err = au_wbr_bu(dentry->d_sb, bstart);
++	AuDbg("b%d\n", err);
++	if (err > bstart)
++		err = au_wbr_nonopq(dentry, err);
++
++	AuDbg("b%d\n", err);
++	return err;
++}
++
++static int au_wbr_copyup_bu(struct dentry *dentry)
++{
++	int err;
++	aufs_bindex_t bstart;
++
++	bstart = au_dbstart(dentry);
++	err = au_wbr_do_copyup_bu(dentry, bstart);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_wbr_copyup_operations au_wbr_copyup_ops[] = {
++	[AuWbrCopyup_TDP] = {
++		.copyup	= au_wbr_copyup_tdp
++	},
++	[AuWbrCopyup_BUP] = {
++		.copyup	= au_wbr_copyup_bup
++	},
++	[AuWbrCopyup_BU] = {
++		.copyup	= au_wbr_copyup_bu
++	}
++};
++
++struct au_wbr_create_operations au_wbr_create_ops[] = {
++	[AuWbrCreate_TDP] = {
++		.create	= au_wbr_create_tdp
++	},
++	[AuWbrCreate_RR] = {
++		.create	= au_wbr_create_rr,
++		.init	= au_wbr_create_init_rr
++	},
++	[AuWbrCreate_MFS] = {
++		.create	= au_wbr_create_mfs,
++		.init	= au_wbr_create_init_mfs,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_MFSV] = {
++		.create	= au_wbr_create_mfs,
++		.init	= au_wbr_create_init_mfs,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_MFSRR] = {
++		.create	= au_wbr_create_mfsrr,
++		.init	= au_wbr_create_init_mfsrr,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_MFSRRV] = {
++		.create	= au_wbr_create_mfsrr,
++		.init	= au_wbr_create_init_mfsrr,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_PMFS] = {
++		.create	= au_wbr_create_pmfs,
++		.init	= au_wbr_create_init_mfs,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_PMFSV] = {
++		.create	= au_wbr_create_pmfs,
++		.init	= au_wbr_create_init_mfs,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_PMFSRR] = {
++		.create	= au_wbr_create_pmfsrr,
++		.init	= au_wbr_create_init_mfsrr,
++		.fin	= au_wbr_create_fin_mfs
++	},
++	[AuWbrCreate_PMFSRRV] = {
++		.create	= au_wbr_create_pmfsrr,
++		.init	= au_wbr_create_init_mfsrr,
++		.fin	= au_wbr_create_fin_mfs
++	}
++};
+diff -Nur linux-4.0.4.orig/fs/aufs/whout.c linux-4.0.4/fs/aufs/whout.c
+--- linux-4.0.4.orig/fs/aufs/whout.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/whout.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,1051 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * whiteout for logical deletion and opaque directory
++ */
++
++#include "aufs.h"
++
++#define WH_MASK			S_IRUGO
++
++/*
++ * If a directory contains this file, then it is opaque.  We start with the
++ * .wh. flag so that it is blocked by lookup.
++ */
++static struct qstr diropq_name = QSTR_INIT(AUFS_WH_DIROPQ,
++					   sizeof(AUFS_WH_DIROPQ) - 1);
++
++/*
++ * generate whiteout name, which is NOT terminated by NULL.
++ * @name: original d_name.name
++ * @len: original d_name.len
++ * @wh: whiteout qstr
++ * returns zero when succeeds, otherwise error.
++ * succeeded value as wh->name should be freed by kfree().
++ */
++int au_wh_name_alloc(struct qstr *wh, const struct qstr *name)
++{
++	char *p;
++
++	if (unlikely(name->len > PATH_MAX - AUFS_WH_PFX_LEN))
++		return -ENAMETOOLONG;
++
++	wh->len = name->len + AUFS_WH_PFX_LEN;
++	p = kmalloc(wh->len, GFP_NOFS);
++	wh->name = p;
++	if (p) {
++		memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
++		memcpy(p + AUFS_WH_PFX_LEN, name->name, name->len);
++		/* smp_mb(); */
++		return 0;
++	}
++	return -ENOMEM;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * test if the @wh_name exists under @h_parent.
++ * @try_sio specifies the necessary of super-io.
++ */
++int au_wh_test(struct dentry *h_parent, struct qstr *wh_name, int try_sio)
++{
++	int err;
++	struct dentry *wh_dentry;
++
++	if (!try_sio)
++		wh_dentry = vfsub_lkup_one(wh_name, h_parent);
++	else
++		wh_dentry = au_sio_lkup_one(wh_name, h_parent);
++	err = PTR_ERR(wh_dentry);
++	if (IS_ERR(wh_dentry)) {
++		if (err == -ENAMETOOLONG)
++			err = 0;
++		goto out;
++	}
++
++	err = 0;
++	if (!wh_dentry->d_inode)
++		goto out_wh; /* success */
++
++	err = 1;
++	if (d_is_reg(wh_dentry))
++		goto out_wh; /* success */
++
++	err = -EIO;
++	AuIOErr("%pd Invalid whiteout entry type 0%o.\n",
++		wh_dentry, wh_dentry->d_inode->i_mode);
++
++out_wh:
++	dput(wh_dentry);
++out:
++	return err;
++}
++
++/*
++ * test if the @h_dentry sets opaque or not.
++ */
++int au_diropq_test(struct dentry *h_dentry)
++{
++	int err;
++	struct inode *h_dir;
++
++	h_dir = h_dentry->d_inode;
++	err = au_wh_test(h_dentry, &diropq_name,
++			 au_test_h_perm_sio(h_dir, MAY_EXEC));
++	return err;
++}
++
++/*
++ * returns a negative dentry whose name is unique and temporary.
++ */
++struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct au_branch *br,
++			     struct qstr *prefix)
++{
++	struct dentry *dentry;
++	int i;
++	char defname[NAME_MAX - AUFS_MAX_NAMELEN + DNAME_INLINE_LEN + 1],
++		*name, *p;
++	/* strict atomic_t is unnecessary here */
++	static unsigned short cnt;
++	struct qstr qs;
++
++	BUILD_BUG_ON(sizeof(cnt) * 2 > AUFS_WH_TMP_LEN);
++
++	name = defname;
++	qs.len = sizeof(defname) - DNAME_INLINE_LEN + prefix->len - 1;
++	if (unlikely(prefix->len > DNAME_INLINE_LEN)) {
++		dentry = ERR_PTR(-ENAMETOOLONG);
++		if (unlikely(qs.len > NAME_MAX))
++			goto out;
++		dentry = ERR_PTR(-ENOMEM);
++		name = kmalloc(qs.len + 1, GFP_NOFS);
++		if (unlikely(!name))
++			goto out;
++	}
++
++	/* doubly whiteout-ed */
++	memcpy(name, AUFS_WH_PFX AUFS_WH_PFX, AUFS_WH_PFX_LEN * 2);
++	p = name + AUFS_WH_PFX_LEN * 2;
++	memcpy(p, prefix->name, prefix->len);
++	p += prefix->len;
++	*p++ = '.';
++	AuDebugOn(name + qs.len + 1 - p <= AUFS_WH_TMP_LEN);
++
++	qs.name = name;
++	for (i = 0; i < 3; i++) {
++		sprintf(p, "%.*x", AUFS_WH_TMP_LEN, cnt++);
++		dentry = au_sio_lkup_one(&qs, h_parent);
++		if (IS_ERR(dentry) || !dentry->d_inode)
++			goto out_name;
++		dput(dentry);
++	}
++	/* pr_warn("could not get random name\n"); */
++	dentry = ERR_PTR(-EEXIST);
++	AuDbg("%.*s\n", AuLNPair(&qs));
++	BUG();
++
++out_name:
++	if (name != defname)
++		kfree(name);
++out:
++	AuTraceErrPtr(dentry);
++	return dentry;
++}
++
++/*
++ * rename the @h_dentry on @br to the whiteouted temporary name.
++ */
++int au_whtmp_ren(struct dentry *h_dentry, struct au_branch *br)
++{
++	int err;
++	struct path h_path = {
++		.mnt = au_br_mnt(br)
++	};
++	struct inode *h_dir, *delegated;
++	struct dentry *h_parent;
++
++	h_parent = h_dentry->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++
++	h_path.dentry = au_whtmp_lkup(h_parent, br, &h_dentry->d_name);
++	err = PTR_ERR(h_path.dentry);
++	if (IS_ERR(h_path.dentry))
++		goto out;
++
++	/* under the same dir, no need to lock_rename() */
++	delegated = NULL;
++	err = vfsub_rename(h_dir, h_dentry, h_dir, &h_path, &delegated);
++	AuTraceErr(err);
++	if (unlikely(err == -EWOULDBLOCK)) {
++		pr_warn("cannot retry for NFSv4 delegation"
++			" for an internal rename\n");
++		iput(delegated);
++	}
++	dput(h_path.dentry);
++
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * functions for removing a whiteout
++ */
++
++static int do_unlink_wh(struct inode *h_dir, struct path *h_path)
++{
++	int err, force;
++	struct inode *delegated;
++
++	/*
++	 * forces superio when the dir has a sticky bit.
++	 * this may be a violation of unix fs semantics.
++	 */
++	force = (h_dir->i_mode & S_ISVTX)
++		&& !uid_eq(current_fsuid(), h_path->dentry->d_inode->i_uid);
++	delegated = NULL;
++	err = vfsub_unlink(h_dir, h_path, &delegated, force);
++	if (unlikely(err == -EWOULDBLOCK)) {
++		pr_warn("cannot retry for NFSv4 delegation"
++			" for an internal unlink\n");
++		iput(delegated);
++	}
++	return err;
++}
++
++int au_wh_unlink_dentry(struct inode *h_dir, struct path *h_path,
++			struct dentry *dentry)
++{
++	int err;
++
++	err = do_unlink_wh(h_dir, h_path);
++	if (!err && dentry)
++		au_set_dbwh(dentry, -1);
++
++	return err;
++}
++
++static int unlink_wh_name(struct dentry *h_parent, struct qstr *wh,
++			  struct au_branch *br)
++{
++	int err;
++	struct path h_path = {
++		.mnt = au_br_mnt(br)
++	};
++
++	err = 0;
++	h_path.dentry = vfsub_lkup_one(wh, h_parent);
++	if (IS_ERR(h_path.dentry))
++		err = PTR_ERR(h_path.dentry);
++	else {
++		if (h_path.dentry->d_inode
++		    && d_is_reg(h_path.dentry))
++			err = do_unlink_wh(h_parent->d_inode, &h_path);
++		dput(h_path.dentry);
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * initialize/clean whiteout for a branch
++ */
++
++static void au_wh_clean(struct inode *h_dir, struct path *whpath,
++			const int isdir)
++{
++	int err;
++	struct inode *delegated;
++
++	if (!whpath->dentry->d_inode)
++		return;
++
++	if (isdir)
++		err = vfsub_rmdir(h_dir, whpath);
++	else {
++		delegated = NULL;
++		err = vfsub_unlink(h_dir, whpath, &delegated, /*force*/0);
++		if (unlikely(err == -EWOULDBLOCK)) {
++			pr_warn("cannot retry for NFSv4 delegation"
++				" for an internal unlink\n");
++			iput(delegated);
++		}
++	}
++	if (unlikely(err))
++		pr_warn("failed removing %pd (%d), ignored.\n",
++			whpath->dentry, err);
++}
++
++static int test_linkable(struct dentry *h_root)
++{
++	struct inode *h_dir = h_root->d_inode;
++
++	if (h_dir->i_op->link)
++		return 0;
++
++	pr_err("%pd (%s) doesn't support link(2), use noplink and rw+nolwh\n",
++	       h_root, au_sbtype(h_root->d_sb));
++	return -ENOSYS;
++}
++
++/* todo: should this mkdir be done in /sbin/mount.aufs helper? */
++static int au_whdir(struct inode *h_dir, struct path *path)
++{
++	int err;
++
++	err = -EEXIST;
++	if (!path->dentry->d_inode) {
++		int mode = S_IRWXU;
++
++		if (au_test_nfs(path->dentry->d_sb))
++			mode |= S_IXUGO;
++		err = vfsub_mkdir(h_dir, path, mode);
++	} else if (d_is_dir(path->dentry))
++		err = 0;
++	else
++		pr_err("unknown %pd exists\n", path->dentry);
++
++	return err;
++}
++
++struct au_wh_base {
++	const struct qstr *name;
++	struct dentry *dentry;
++};
++
++static void au_wh_init_ro(struct inode *h_dir, struct au_wh_base base[],
++			  struct path *h_path)
++{
++	h_path->dentry = base[AuBrWh_BASE].dentry;
++	au_wh_clean(h_dir, h_path, /*isdir*/0);
++	h_path->dentry = base[AuBrWh_PLINK].dentry;
++	au_wh_clean(h_dir, h_path, /*isdir*/1);
++	h_path->dentry = base[AuBrWh_ORPH].dentry;
++	au_wh_clean(h_dir, h_path, /*isdir*/1);
++}
++
++/*
++ * returns tri-state,
++ * minus: error, caller should print the message
++ * zero: succuess
++ * plus: error, caller should NOT print the message
++ */
++static int au_wh_init_rw_nolink(struct dentry *h_root, struct au_wbr *wbr,
++				int do_plink, struct au_wh_base base[],
++				struct path *h_path)
++{
++	int err;
++	struct inode *h_dir;
++
++	h_dir = h_root->d_inode;
++	h_path->dentry = base[AuBrWh_BASE].dentry;
++	au_wh_clean(h_dir, h_path, /*isdir*/0);
++	h_path->dentry = base[AuBrWh_PLINK].dentry;
++	if (do_plink) {
++		err = test_linkable(h_root);
++		if (unlikely(err)) {
++			err = 1;
++			goto out;
++		}
++
++		err = au_whdir(h_dir, h_path);
++		if (unlikely(err))
++			goto out;
++		wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
++	} else
++		au_wh_clean(h_dir, h_path, /*isdir*/1);
++	h_path->dentry = base[AuBrWh_ORPH].dentry;
++	err = au_whdir(h_dir, h_path);
++	if (unlikely(err))
++		goto out;
++	wbr->wbr_orph = dget(base[AuBrWh_ORPH].dentry);
++
++out:
++	return err;
++}
++
++/*
++ * for the moment, aufs supports the branch filesystem which does not support
++ * link(2). testing on FAT which does not support i_op->setattr() fully either,
++ * copyup failed. finally, such filesystem will not be used as the writable
++ * branch.
++ *
++ * returns tri-state, see above.
++ */
++static int au_wh_init_rw(struct dentry *h_root, struct au_wbr *wbr,
++			 int do_plink, struct au_wh_base base[],
++			 struct path *h_path)
++{
++	int err;
++	struct inode *h_dir;
++
++	WbrWhMustWriteLock(wbr);
++
++	err = test_linkable(h_root);
++	if (unlikely(err)) {
++		err = 1;
++		goto out;
++	}
++
++	/*
++	 * todo: should this create be done in /sbin/mount.aufs helper?
++	 */
++	err = -EEXIST;
++	h_dir = h_root->d_inode;
++	if (!base[AuBrWh_BASE].dentry->d_inode) {
++		h_path->dentry = base[AuBrWh_BASE].dentry;
++		err = vfsub_create(h_dir, h_path, WH_MASK, /*want_excl*/true);
++	} else if (d_is_reg(base[AuBrWh_BASE].dentry))
++		err = 0;
++	else
++		pr_err("unknown %pd2 exists\n", base[AuBrWh_BASE].dentry);
++	if (unlikely(err))
++		goto out;
++
++	h_path->dentry = base[AuBrWh_PLINK].dentry;
++	if (do_plink) {
++		err = au_whdir(h_dir, h_path);
++		if (unlikely(err))
++			goto out;
++		wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
++	} else
++		au_wh_clean(h_dir, h_path, /*isdir*/1);
++	wbr->wbr_whbase = dget(base[AuBrWh_BASE].dentry);
++
++	h_path->dentry = base[AuBrWh_ORPH].dentry;
++	err = au_whdir(h_dir, h_path);
++	if (unlikely(err))
++		goto out;
++	wbr->wbr_orph = dget(base[AuBrWh_ORPH].dentry);
++
++out:
++	return err;
++}
++
++/*
++ * initialize the whiteout base file/dir for @br.
++ */
++int au_wh_init(struct au_branch *br, struct super_block *sb)
++{
++	int err, i;
++	const unsigned char do_plink
++		= !!au_opt_test(au_mntflags(sb), PLINK);
++	struct inode *h_dir;
++	struct path path = br->br_path;
++	struct dentry *h_root = path.dentry;
++	struct au_wbr *wbr = br->br_wbr;
++	static const struct qstr base_name[] = {
++		[AuBrWh_BASE] = QSTR_INIT(AUFS_BASE_NAME,
++					  sizeof(AUFS_BASE_NAME) - 1),
++		[AuBrWh_PLINK] = QSTR_INIT(AUFS_PLINKDIR_NAME,
++					   sizeof(AUFS_PLINKDIR_NAME) - 1),
++		[AuBrWh_ORPH] = QSTR_INIT(AUFS_ORPHDIR_NAME,
++					  sizeof(AUFS_ORPHDIR_NAME) - 1)
++	};
++	struct au_wh_base base[] = {
++		[AuBrWh_BASE] = {
++			.name	= base_name + AuBrWh_BASE,
++			.dentry	= NULL
++		},
++		[AuBrWh_PLINK] = {
++			.name	= base_name + AuBrWh_PLINK,
++			.dentry	= NULL
++		},
++		[AuBrWh_ORPH] = {
++			.name	= base_name + AuBrWh_ORPH,
++			.dentry	= NULL
++		}
++	};
++
++	if (wbr)
++		WbrWhMustWriteLock(wbr);
++
++	for (i = 0; i < AuBrWh_Last; i++) {
++		/* doubly whiteouted */
++		struct dentry *d;
++
++		d = au_wh_lkup(h_root, (void *)base[i].name, br);
++		err = PTR_ERR(d);
++		if (IS_ERR(d))
++			goto out;
++
++		base[i].dentry = d;
++		AuDebugOn(wbr
++			  && wbr->wbr_wh[i]
++			  && wbr->wbr_wh[i] != base[i].dentry);
++	}
++
++	if (wbr)
++		for (i = 0; i < AuBrWh_Last; i++) {
++			dput(wbr->wbr_wh[i]);
++			wbr->wbr_wh[i] = NULL;
++		}
++
++	err = 0;
++	if (!au_br_writable(br->br_perm)) {
++		h_dir = h_root->d_inode;
++		au_wh_init_ro(h_dir, base, &path);
++	} else if (!au_br_wh_linkable(br->br_perm)) {
++		err = au_wh_init_rw_nolink(h_root, wbr, do_plink, base, &path);
++		if (err > 0)
++			goto out;
++		else if (err)
++			goto out_err;
++	} else {
++		err = au_wh_init_rw(h_root, wbr, do_plink, base, &path);
++		if (err > 0)
++			goto out;
++		else if (err)
++			goto out_err;
++	}
++	goto out; /* success */
++
++out_err:
++	pr_err("an error(%d) on the writable branch %pd(%s)\n",
++	       err, h_root, au_sbtype(h_root->d_sb));
++out:
++	for (i = 0; i < AuBrWh_Last; i++)
++		dput(base[i].dentry);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++/*
++ * whiteouts are all hard-linked usually.
++ * when its link count reaches a ceiling, we create a new whiteout base
++ * asynchronously.
++ */
++
++struct reinit_br_wh {
++	struct super_block *sb;
++	struct au_branch *br;
++};
++
++static void reinit_br_wh(void *arg)
++{
++	int err;
++	aufs_bindex_t bindex;
++	struct path h_path;
++	struct reinit_br_wh *a = arg;
++	struct au_wbr *wbr;
++	struct inode *dir, *delegated;
++	struct dentry *h_root;
++	struct au_hinode *hdir;
++
++	err = 0;
++	wbr = a->br->br_wbr;
++	/* big aufs lock */
++	si_noflush_write_lock(a->sb);
++	if (!au_br_writable(a->br->br_perm))
++		goto out;
++	bindex = au_br_index(a->sb, a->br->br_id);
++	if (unlikely(bindex < 0))
++		goto out;
++
++	di_read_lock_parent(a->sb->s_root, AuLock_IR);
++	dir = a->sb->s_root->d_inode;
++	hdir = au_hi(dir, bindex);
++	h_root = au_h_dptr(a->sb->s_root, bindex);
++	AuDebugOn(h_root != au_br_dentry(a->br));
++
++	au_hn_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++	wbr_wh_write_lock(wbr);
++	err = au_h_verify(wbr->wbr_whbase, au_opt_udba(a->sb), hdir->hi_inode,
++			  h_root, a->br);
++	if (!err) {
++		h_path.dentry = wbr->wbr_whbase;
++		h_path.mnt = au_br_mnt(a->br);
++		delegated = NULL;
++		err = vfsub_unlink(hdir->hi_inode, &h_path, &delegated,
++				   /*force*/0);
++		if (unlikely(err == -EWOULDBLOCK)) {
++			pr_warn("cannot retry for NFSv4 delegation"
++				" for an internal unlink\n");
++			iput(delegated);
++		}
++	} else {
++		pr_warn("%pd is moved, ignored\n", wbr->wbr_whbase);
++		err = 0;
++	}
++	dput(wbr->wbr_whbase);
++	wbr->wbr_whbase = NULL;
++	if (!err)
++		err = au_wh_init(a->br, a->sb);
++	wbr_wh_write_unlock(wbr);
++	au_hn_imtx_unlock(hdir);
++	di_read_unlock(a->sb->s_root, AuLock_IR);
++	if (!err)
++		au_fhsm_wrote(a->sb, bindex, /*force*/0);
++
++out:
++	if (wbr)
++		atomic_dec(&wbr->wbr_wh_running);
++	atomic_dec(&a->br->br_count);
++	si_write_unlock(a->sb);
++	au_nwt_done(&au_sbi(a->sb)->si_nowait);
++	kfree(arg);
++	if (unlikely(err))
++		AuIOErr("err %d\n", err);
++}
++
++static void kick_reinit_br_wh(struct super_block *sb, struct au_branch *br)
++{
++	int do_dec, wkq_err;
++	struct reinit_br_wh *arg;
++
++	do_dec = 1;
++	if (atomic_inc_return(&br->br_wbr->wbr_wh_running) != 1)
++		goto out;
++
++	/* ignore ENOMEM */
++	arg = kmalloc(sizeof(*arg), GFP_NOFS);
++	if (arg) {
++		/*
++		 * dec(wh_running), kfree(arg) and dec(br_count)
++		 * in reinit function
++		 */
++		arg->sb = sb;
++		arg->br = br;
++		atomic_inc(&br->br_count);
++		wkq_err = au_wkq_nowait(reinit_br_wh, arg, sb, /*flags*/0);
++		if (unlikely(wkq_err)) {
++			atomic_dec(&br->br_wbr->wbr_wh_running);
++			atomic_dec(&br->br_count);
++			kfree(arg);
++		}
++		do_dec = 0;
++	}
++
++out:
++	if (do_dec)
++		atomic_dec(&br->br_wbr->wbr_wh_running);
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * create the whiteout @wh.
++ */
++static int link_or_create_wh(struct super_block *sb, aufs_bindex_t bindex,
++			     struct dentry *wh)
++{
++	int err;
++	struct path h_path = {
++		.dentry = wh
++	};
++	struct au_branch *br;
++	struct au_wbr *wbr;
++	struct dentry *h_parent;
++	struct inode *h_dir, *delegated;
++
++	h_parent = wh->d_parent; /* dir inode is locked */
++	h_dir = h_parent->d_inode;
++	IMustLock(h_dir);
++
++	br = au_sbr(sb, bindex);
++	h_path.mnt = au_br_mnt(br);
++	wbr = br->br_wbr;
++	wbr_wh_read_lock(wbr);
++	if (wbr->wbr_whbase) {
++		delegated = NULL;
++		err = vfsub_link(wbr->wbr_whbase, h_dir, &h_path, &delegated);
++		if (unlikely(err == -EWOULDBLOCK)) {
++			pr_warn("cannot retry for NFSv4 delegation"
++				" for an internal link\n");
++			iput(delegated);
++		}
++		if (!err || err != -EMLINK)
++			goto out;
++
++		/* link count full. re-initialize br_whbase. */
++		kick_reinit_br_wh(sb, br);
++	}
++
++	/* return this error in this context */
++	err = vfsub_create(h_dir, &h_path, WH_MASK, /*want_excl*/true);
++	if (!err)
++		au_fhsm_wrote(sb, bindex, /*force*/0);
++
++out:
++	wbr_wh_read_unlock(wbr);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * create or remove the diropq.
++ */
++static struct dentry *do_diropq(struct dentry *dentry, aufs_bindex_t bindex,
++				unsigned int flags)
++{
++	struct dentry *opq_dentry, *h_dentry;
++	struct super_block *sb;
++	struct au_branch *br;
++	int err;
++
++	sb = dentry->d_sb;
++	br = au_sbr(sb, bindex);
++	h_dentry = au_h_dptr(dentry, bindex);
++	opq_dentry = vfsub_lkup_one(&diropq_name, h_dentry);
++	if (IS_ERR(opq_dentry))
++		goto out;
++
++	if (au_ftest_diropq(flags, CREATE)) {
++		err = link_or_create_wh(sb, bindex, opq_dentry);
++		if (!err) {
++			au_set_dbdiropq(dentry, bindex);
++			goto out; /* success */
++		}
++	} else {
++		struct path tmp = {
++			.dentry = opq_dentry,
++			.mnt	= au_br_mnt(br)
++		};
++		err = do_unlink_wh(au_h_iptr(dentry->d_inode, bindex), &tmp);
++		if (!err)
++			au_set_dbdiropq(dentry, -1);
++	}
++	dput(opq_dentry);
++	opq_dentry = ERR_PTR(err);
++
++out:
++	return opq_dentry;
++}
++
++struct do_diropq_args {
++	struct dentry **errp;
++	struct dentry *dentry;
++	aufs_bindex_t bindex;
++	unsigned int flags;
++};
++
++static void call_do_diropq(void *args)
++{
++	struct do_diropq_args *a = args;
++	*a->errp = do_diropq(a->dentry, a->bindex, a->flags);
++}
++
++struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
++			     unsigned int flags)
++{
++	struct dentry *diropq, *h_dentry;
++
++	h_dentry = au_h_dptr(dentry, bindex);
++	if (!au_test_h_perm_sio(h_dentry->d_inode, MAY_EXEC | MAY_WRITE))
++		diropq = do_diropq(dentry, bindex, flags);
++	else {
++		int wkq_err;
++		struct do_diropq_args args = {
++			.errp		= &diropq,
++			.dentry		= dentry,
++			.bindex		= bindex,
++			.flags		= flags
++		};
++
++		wkq_err = au_wkq_wait(call_do_diropq, &args);
++		if (unlikely(wkq_err))
++			diropq = ERR_PTR(wkq_err);
++	}
++
++	return diropq;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * lookup whiteout dentry.
++ * @h_parent: lower parent dentry which must exist and be locked
++ * @base_name: name of dentry which will be whiteouted
++ * returns dentry for whiteout.
++ */
++struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
++			  struct au_branch *br)
++{
++	int err;
++	struct qstr wh_name;
++	struct dentry *wh_dentry;
++
++	err = au_wh_name_alloc(&wh_name, base_name);
++	wh_dentry = ERR_PTR(err);
++	if (!err) {
++		wh_dentry = vfsub_lkup_one(&wh_name, h_parent);
++		kfree(wh_name.name);
++	}
++	return wh_dentry;
++}
++
++/*
++ * link/create a whiteout for @dentry on @bindex.
++ */
++struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
++			    struct dentry *h_parent)
++{
++	struct dentry *wh_dentry;
++	struct super_block *sb;
++	int err;
++
++	sb = dentry->d_sb;
++	wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, au_sbr(sb, bindex));
++	if (!IS_ERR(wh_dentry) && !wh_dentry->d_inode) {
++		err = link_or_create_wh(sb, bindex, wh_dentry);
++		if (!err) {
++			au_set_dbwh(dentry, bindex);
++			au_fhsm_wrote(sb, bindex, /*force*/0);
++		} else {
++			dput(wh_dentry);
++			wh_dentry = ERR_PTR(err);
++		}
++	}
++
++	return wh_dentry;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* Delete all whiteouts in this directory on branch bindex. */
++static int del_wh_children(struct dentry *h_dentry, struct au_nhash *whlist,
++			   aufs_bindex_t bindex, struct au_branch *br)
++{
++	int err;
++	unsigned long ul, n;
++	struct qstr wh_name;
++	char *p;
++	struct hlist_head *head;
++	struct au_vdir_wh *pos;
++	struct au_vdir_destr *str;
++
++	err = -ENOMEM;
++	p = (void *)__get_free_page(GFP_NOFS);
++	wh_name.name = p;
++	if (unlikely(!wh_name.name))
++		goto out;
++
++	err = 0;
++	memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
++	p += AUFS_WH_PFX_LEN;
++	n = whlist->nh_num;
++	head = whlist->nh_head;
++	for (ul = 0; !err && ul < n; ul++, head++) {
++		hlist_for_each_entry(pos, head, wh_hash) {
++			if (pos->wh_bindex != bindex)
++				continue;
++
++			str = &pos->wh_str;
++			if (str->len + AUFS_WH_PFX_LEN <= PATH_MAX) {
++				memcpy(p, str->name, str->len);
++				wh_name.len = AUFS_WH_PFX_LEN + str->len;
++				err = unlink_wh_name(h_dentry, &wh_name, br);
++				if (!err)
++					continue;
++				break;
++			}
++			AuIOErr("whiteout name too long %.*s\n",
++				str->len, str->name);
++			err = -EIO;
++			break;
++		}
++	}
++	free_page((unsigned long)wh_name.name);
++
++out:
++	return err;
++}
++
++struct del_wh_children_args {
++	int *errp;
++	struct dentry *h_dentry;
++	struct au_nhash *whlist;
++	aufs_bindex_t bindex;
++	struct au_branch *br;
++};
++
++static void call_del_wh_children(void *args)
++{
++	struct del_wh_children_args *a = args;
++	*a->errp = del_wh_children(a->h_dentry, a->whlist, a->bindex, a->br);
++}
++
++/* ---------------------------------------------------------------------- */
++
++struct au_whtmp_rmdir *au_whtmp_rmdir_alloc(struct super_block *sb, gfp_t gfp)
++{
++	struct au_whtmp_rmdir *whtmp;
++	int err;
++	unsigned int rdhash;
++
++	SiMustAnyLock(sb);
++
++	whtmp = kmalloc(sizeof(*whtmp), gfp);
++	if (unlikely(!whtmp)) {
++		whtmp = ERR_PTR(-ENOMEM);
++		goto out;
++	}
++
++	whtmp->dir = NULL;
++	whtmp->br = NULL;
++	whtmp->wh_dentry = NULL;
++	/* no estimation for dir size */
++	rdhash = au_sbi(sb)->si_rdhash;
++	if (!rdhash)
++		rdhash = AUFS_RDHASH_DEF;
++	err = au_nhash_alloc(&whtmp->whlist, rdhash, gfp);
++	if (unlikely(err)) {
++		kfree(whtmp);
++		whtmp = ERR_PTR(err);
++	}
++
++out:
++	return whtmp;
++}
++
++void au_whtmp_rmdir_free(struct au_whtmp_rmdir *whtmp)
++{
++	if (whtmp->br)
++		atomic_dec(&whtmp->br->br_count);
++	dput(whtmp->wh_dentry);
++	iput(whtmp->dir);
++	au_nhash_wh_free(&whtmp->whlist);
++	kfree(whtmp);
++}
++
++/*
++ * rmdir the whiteouted temporary named dir @h_dentry.
++ * @whlist: whiteouted children.
++ */
++int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
++		   struct dentry *wh_dentry, struct au_nhash *whlist)
++{
++	int err;
++	unsigned int h_nlink;
++	struct path h_tmp;
++	struct inode *wh_inode, *h_dir;
++	struct au_branch *br;
++
++	h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
++	IMustLock(h_dir);
++
++	br = au_sbr(dir->i_sb, bindex);
++	wh_inode = wh_dentry->d_inode;
++	mutex_lock_nested(&wh_inode->i_mutex, AuLsc_I_CHILD);
++
++	/*
++	 * someone else might change some whiteouts while we were sleeping.
++	 * it means this whlist may have an obsoleted entry.
++	 */
++	if (!au_test_h_perm_sio(wh_inode, MAY_EXEC | MAY_WRITE))
++		err = del_wh_children(wh_dentry, whlist, bindex, br);
++	else {
++		int wkq_err;
++		struct del_wh_children_args args = {
++			.errp		= &err,
++			.h_dentry	= wh_dentry,
++			.whlist		= whlist,
++			.bindex		= bindex,
++			.br		= br
++		};
++
++		wkq_err = au_wkq_wait(call_del_wh_children, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++	mutex_unlock(&wh_inode->i_mutex);
++
++	if (!err) {
++		h_tmp.dentry = wh_dentry;
++		h_tmp.mnt = au_br_mnt(br);
++		h_nlink = h_dir->i_nlink;
++		err = vfsub_rmdir(h_dir, &h_tmp);
++		/* some fs doesn't change the parent nlink in some cases */
++		h_nlink -= h_dir->i_nlink;
++	}
++
++	if (!err) {
++		if (au_ibstart(dir) == bindex) {
++			/* todo: dir->i_mutex is necessary */
++			au_cpup_attr_timesizes(dir);
++			if (h_nlink)
++				vfsub_drop_nlink(dir);
++		}
++		return 0; /* success */
++	}
++
++	pr_warn("failed removing %pd(%d), ignored\n", wh_dentry, err);
++	return err;
++}
++
++static void call_rmdir_whtmp(void *args)
++{
++	int err;
++	aufs_bindex_t bindex;
++	struct au_whtmp_rmdir *a = args;
++	struct super_block *sb;
++	struct dentry *h_parent;
++	struct inode *h_dir;
++	struct au_hinode *hdir;
++
++	/* rmdir by nfsd may cause deadlock with this i_mutex */
++	/* mutex_lock(&a->dir->i_mutex); */
++	err = -EROFS;
++	sb = a->dir->i_sb;
++	si_read_lock(sb, !AuLock_FLUSH);
++	if (!au_br_writable(a->br->br_perm))
++		goto out;
++	bindex = au_br_index(sb, a->br->br_id);
++	if (unlikely(bindex < 0))
++		goto out;
++
++	err = -EIO;
++	ii_write_lock_parent(a->dir);
++	h_parent = dget_parent(a->wh_dentry);
++	h_dir = h_parent->d_inode;
++	hdir = au_hi(a->dir, bindex);
++	err = vfsub_mnt_want_write(au_br_mnt(a->br));
++	if (unlikely(err))
++		goto out_mnt;
++	au_hn_imtx_lock_nested(hdir, AuLsc_I_PARENT);
++	err = au_h_verify(a->wh_dentry, au_opt_udba(sb), h_dir, h_parent,
++			  a->br);
++	if (!err)
++		err = au_whtmp_rmdir(a->dir, bindex, a->wh_dentry, &a->whlist);
++	au_hn_imtx_unlock(hdir);
++	vfsub_mnt_drop_write(au_br_mnt(a->br));
++
++out_mnt:
++	dput(h_parent);
++	ii_write_unlock(a->dir);
++out:
++	/* mutex_unlock(&a->dir->i_mutex); */
++	au_whtmp_rmdir_free(a);
++	si_read_unlock(sb);
++	au_nwt_done(&au_sbi(sb)->si_nowait);
++	if (unlikely(err))
++		AuIOErr("err %d\n", err);
++}
++
++void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
++			 struct dentry *wh_dentry, struct au_whtmp_rmdir *args)
++{
++	int wkq_err;
++	struct super_block *sb;
++
++	IMustLock(dir);
++
++	/* all post-process will be done in do_rmdir_whtmp(). */
++	sb = dir->i_sb;
++	args->dir = au_igrab(dir);
++	args->br = au_sbr(sb, bindex);
++	atomic_inc(&args->br->br_count);
++	args->wh_dentry = dget(wh_dentry);
++	wkq_err = au_wkq_nowait(call_rmdir_whtmp, args, sb, /*flags*/0);
++	if (unlikely(wkq_err)) {
++		pr_warn("rmdir error %pd (%d), ignored\n", wh_dentry, wkq_err);
++		au_whtmp_rmdir_free(args);
++	}
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/whout.h linux-4.0.4/fs/aufs/whout.h
+--- linux-4.0.4.orig/fs/aufs/whout.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/whout.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,72 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * whiteout for logical deletion and opaque directory
++ */
++
++#ifndef __AUFS_WHOUT_H__
++#define __AUFS_WHOUT_H__
++
++#ifdef __KERNEL__
++
++#include "dir.h"
++
++/* whout.c */
++int au_wh_name_alloc(struct qstr *wh, const struct qstr *name);
++int au_wh_test(struct dentry *h_parent, struct qstr *wh_name, int try_sio);
++int au_diropq_test(struct dentry *h_dentry);
++struct au_branch;
++struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct au_branch *br,
++			     struct qstr *prefix);
++int au_whtmp_ren(struct dentry *h_dentry, struct au_branch *br);
++int au_wh_unlink_dentry(struct inode *h_dir, struct path *h_path,
++			struct dentry *dentry);
++int au_wh_init(struct au_branch *br, struct super_block *sb);
++
++/* diropq flags */
++#define AuDiropq_CREATE	1
++#define au_ftest_diropq(flags, name)	((flags) & AuDiropq_##name)
++#define au_fset_diropq(flags, name) \
++	do { (flags) |= AuDiropq_##name; } while (0)
++#define au_fclr_diropq(flags, name) \
++	do { (flags) &= ~AuDiropq_##name; } while (0)
++
++struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
++			     unsigned int flags);
++struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
++			  struct au_branch *br);
++struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
++			    struct dentry *h_parent);
++
++/* real rmdir for the whiteout-ed dir */
++struct au_whtmp_rmdir {
++	struct inode *dir;
++	struct au_branch *br;
++	struct dentry *wh_dentry;
++	struct au_nhash whlist;
++};
++
++struct au_whtmp_rmdir *au_whtmp_rmdir_alloc(struct super_block *sb, gfp_t gfp);
++void au_whtmp_rmdir_free(struct au_whtmp_rmdir *whtmp);
++int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
++		   struct dentry *wh_dentry, struct au_nhash *whlist);
++void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
++			 struct dentry *wh_dentry, struct au_whtmp_rmdir *args);
++
++/* ---------------------------------------------------------------------- */
++
++static inline struct dentry *au_diropq_create(struct dentry *dentry,
++					      aufs_bindex_t bindex)
++{
++	return au_diropq_sio(dentry, bindex, AuDiropq_CREATE);
++}
++
++static inline int au_diropq_remove(struct dentry *dentry, aufs_bindex_t bindex)
++{
++	return PTR_ERR(au_diropq_sio(dentry, bindex, !AuDiropq_CREATE));
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_WHOUT_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/wkq.c linux-4.0.4/fs/aufs/wkq.c
+--- linux-4.0.4.orig/fs/aufs/wkq.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/wkq.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,200 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * workqueue for asynchronous/super-io operations
++ * todo: try new dredential scheme
++ */
++
++#include <linux/module.h>
++#include "aufs.h"
++
++/* internal workqueue named AUFS_WKQ_NAME */
++
++static struct workqueue_struct *au_wkq;
++
++struct au_wkinfo {
++	struct work_struct wk;
++	struct kobject *kobj;
++
++	unsigned int flags; /* see wkq.h */
++
++	au_wkq_func_t func;
++	void *args;
++
++	struct completion *comp;
++};
++
++/* ---------------------------------------------------------------------- */
++
++static void wkq_func(struct work_struct *wk)
++{
++	struct au_wkinfo *wkinfo = container_of(wk, struct au_wkinfo, wk);
++
++	AuDebugOn(!uid_eq(current_fsuid(), GLOBAL_ROOT_UID));
++	AuDebugOn(rlimit(RLIMIT_FSIZE) != RLIM_INFINITY);
++
++	wkinfo->func(wkinfo->args);
++	if (au_ftest_wkq(wkinfo->flags, WAIT))
++		complete(wkinfo->comp);
++	else {
++		kobject_put(wkinfo->kobj);
++		module_put(THIS_MODULE); /* todo: ?? */
++		kfree(wkinfo);
++	}
++}
++
++/*
++ * Since struct completion is large, try allocating it dynamically.
++ */
++#if 1 /* defined(CONFIG_4KSTACKS) || defined(AuTest4KSTACKS) */
++#define AuWkqCompDeclare(name)	struct completion *comp = NULL
++
++static int au_wkq_comp_alloc(struct au_wkinfo *wkinfo, struct completion **comp)
++{
++	*comp = kmalloc(sizeof(**comp), GFP_NOFS);
++	if (*comp) {
++		init_completion(*comp);
++		wkinfo->comp = *comp;
++		return 0;
++	}
++	return -ENOMEM;
++}
++
++static void au_wkq_comp_free(struct completion *comp)
++{
++	kfree(comp);
++}
++
++#else
++
++/* no braces */
++#define AuWkqCompDeclare(name) \
++	DECLARE_COMPLETION_ONSTACK(_ ## name); \
++	struct completion *comp = &_ ## name
++
++static int au_wkq_comp_alloc(struct au_wkinfo *wkinfo, struct completion **comp)
++{
++	wkinfo->comp = *comp;
++	return 0;
++}
++
++static void au_wkq_comp_free(struct completion *comp __maybe_unused)
++{
++	/* empty */
++}
++#endif /* 4KSTACKS */
++
++static void au_wkq_run(struct au_wkinfo *wkinfo)
++{
++	if (au_ftest_wkq(wkinfo->flags, NEST)) {
++		if (au_wkq_test()) {
++			AuWarn1("wkq from wkq, unless silly-rename on NFS,"
++				" due to a dead dir by UDBA?\n");
++			AuDebugOn(au_ftest_wkq(wkinfo->flags, WAIT));
++		}
++	} else
++		au_dbg_verify_kthread();
++
++	if (au_ftest_wkq(wkinfo->flags, WAIT)) {
++		INIT_WORK_ONSTACK(&wkinfo->wk, wkq_func);
++		queue_work(au_wkq, &wkinfo->wk);
++	} else {
++		INIT_WORK(&wkinfo->wk, wkq_func);
++		schedule_work(&wkinfo->wk);
++	}
++}
++
++/*
++ * Be careful. It is easy to make deadlock happen.
++ * processA: lock, wkq and wait
++ * processB: wkq and wait, lock in wkq
++ * --> deadlock
++ */
++int au_wkq_do_wait(unsigned int flags, au_wkq_func_t func, void *args)
++{
++	int err;
++	AuWkqCompDeclare(comp);
++	struct au_wkinfo wkinfo = {
++		.flags	= flags,
++		.func	= func,
++		.args	= args
++	};
++
++	err = au_wkq_comp_alloc(&wkinfo, &comp);
++	if (!err) {
++		au_wkq_run(&wkinfo);
++		/* no timeout, no interrupt */
++		wait_for_completion(wkinfo.comp);
++		au_wkq_comp_free(comp);
++		destroy_work_on_stack(&wkinfo.wk);
++	}
++
++	return err;
++
++}
++
++/*
++ * Note: dget/dput() in func for aufs dentries are not supported. It will be a
++ * problem in a concurrent umounting.
++ */
++int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb,
++		  unsigned int flags)
++{
++	int err;
++	struct au_wkinfo *wkinfo;
++
++	atomic_inc(&au_sbi(sb)->si_nowait.nw_len);
++
++	/*
++	 * wkq_func() must free this wkinfo.
++	 * it highly depends upon the implementation of workqueue.
++	 */
++	err = 0;
++	wkinfo = kmalloc(sizeof(*wkinfo), GFP_NOFS);
++	if (wkinfo) {
++		wkinfo->kobj = &au_sbi(sb)->si_kobj;
++		wkinfo->flags = flags & ~AuWkq_WAIT;
++		wkinfo->func = func;
++		wkinfo->args = args;
++		wkinfo->comp = NULL;
++		kobject_get(wkinfo->kobj);
++		__module_get(THIS_MODULE); /* todo: ?? */
++
++		au_wkq_run(wkinfo);
++	} else {
++		err = -ENOMEM;
++		au_nwt_done(&au_sbi(sb)->si_nowait);
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++void au_nwt_init(struct au_nowait_tasks *nwt)
++{
++	atomic_set(&nwt->nw_len, 0);
++	/* smp_mb(); */ /* atomic_set */
++	init_waitqueue_head(&nwt->nw_wq);
++}
++
++void au_wkq_fin(void)
++{
++	destroy_workqueue(au_wkq);
++}
++
++int __init au_wkq_init(void)
++{
++	int err;
++
++	err = 0;
++	au_wkq = alloc_workqueue(AUFS_WKQ_NAME, 0, WQ_DFL_ACTIVE);
++	if (IS_ERR(au_wkq))
++		err = PTR_ERR(au_wkq);
++	else if (!au_wkq)
++		err = -ENOMEM;
++
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/aufs/wkq.h linux-4.0.4/fs/aufs/wkq.h
+--- linux-4.0.4.orig/fs/aufs/wkq.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/wkq.h	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,78 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * workqueue for asynchronous/super-io operations
++ * todo: try new credentials management scheme
++ */
++
++#ifndef __AUFS_WKQ_H__
++#define __AUFS_WKQ_H__
++
++#ifdef __KERNEL__
++
++struct super_block;
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * in the next operation, wait for the 'nowait' tasks in system-wide workqueue
++ */
++struct au_nowait_tasks {
++	atomic_t		nw_len;
++	wait_queue_head_t	nw_wq;
++};
++
++/* ---------------------------------------------------------------------- */
++
++typedef void (*au_wkq_func_t)(void *args);
++
++/* wkq flags */
++#define AuWkq_WAIT	1
++#define AuWkq_NEST	(1 << 1)
++#define au_ftest_wkq(flags, name)	((flags) & AuWkq_##name)
++#define au_fset_wkq(flags, name) \
++	do { (flags) |= AuWkq_##name; } while (0)
++#define au_fclr_wkq(flags, name) \
++	do { (flags) &= ~AuWkq_##name; } while (0)
++
++#ifndef CONFIG_AUFS_HNOTIFY
++#undef AuWkq_NEST
++#define AuWkq_NEST	0
++#endif
++
++/* wkq.c */
++int au_wkq_do_wait(unsigned int flags, au_wkq_func_t func, void *args);
++int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb,
++		  unsigned int flags);
++void au_nwt_init(struct au_nowait_tasks *nwt);
++int __init au_wkq_init(void);
++void au_wkq_fin(void);
++
++/* ---------------------------------------------------------------------- */
++
++static inline int au_wkq_test(void)
++{
++	return current->flags & PF_WQ_WORKER;
++}
++
++static inline int au_wkq_wait(au_wkq_func_t func, void *args)
++{
++	return au_wkq_do_wait(AuWkq_WAIT, func, args);
++}
++
++static inline void au_nwt_done(struct au_nowait_tasks *nwt)
++{
++	if (atomic_dec_and_test(&nwt->nw_len))
++		wake_up_all(&nwt->nw_wq);
++}
++
++static inline int au_nwt_flush(struct au_nowait_tasks *nwt)
++{
++	wait_event(nwt->nw_wq, !atomic_read(&nwt->nw_len));
++	return 0;
++}
++
++#endif /* __KERNEL__ */
++#endif /* __AUFS_WKQ_H__ */
+diff -Nur linux-4.0.4.orig/fs/aufs/xattr.c linux-4.0.4/fs/aufs/xattr.c
+--- linux-4.0.4.orig/fs/aufs/xattr.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/xattr.c	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,331 @@
++/*
++ * Copyright (C) 2014-2015 Junjiro R. Okajima
++ */
++
++/*
++ * handling xattr functions
++ */
++
++#include <linux/xattr.h>
++#include "aufs.h"
++
++static int au_xattr_ignore(int err, char *name, unsigned int ignore_flags)
++{
++	if (!ignore_flags)
++		goto out;
++	switch (err) {
++	case -ENOMEM:
++	case -EDQUOT:
++		goto out;
++	}
++
++	if ((ignore_flags & AuBrAttr_ICEX) == AuBrAttr_ICEX) {
++		err = 0;
++		goto out;
++	}
++
++#define cmp(brattr, prefix) do {					\
++		if (!strncmp(name, XATTR_##prefix##_PREFIX,		\
++			     XATTR_##prefix##_PREFIX_LEN)) {		\
++			if (ignore_flags & AuBrAttr_ICEX_##brattr)	\
++				err = 0;				\
++			goto out;					\
++		}							\
++	} while (0)
++
++	cmp(SEC, SECURITY);
++	cmp(SYS, SYSTEM);
++	cmp(TR, TRUSTED);
++	cmp(USR, USER);
++#undef cmp
++
++	if (ignore_flags & AuBrAttr_ICEX_OTH)
++		err = 0;
++
++out:
++	return err;
++}
++
++static const int au_xattr_out_of_list = AuBrAttr_ICEX_OTH << 1;
++
++static int au_do_cpup_xattr(struct dentry *h_dst, struct dentry *h_src,
++			    char *name, char **buf, unsigned int ignore_flags,
++			    unsigned int verbose)
++{
++	int err;
++	ssize_t ssz;
++	struct inode *h_idst;
++
++	ssz = vfs_getxattr_alloc(h_src, name, buf, 0, GFP_NOFS);
++	err = ssz;
++	if (unlikely(err <= 0)) {
++		if (err == -ENODATA
++		    || (err == -EOPNOTSUPP
++			&& ((ignore_flags & au_xattr_out_of_list)
++			    || (au_test_nfs_noacl(h_src->d_inode)
++				&& (!strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS)
++				    || !strcmp(name,
++					       XATTR_NAME_POSIX_ACL_DEFAULT))))
++			    ))
++			err = 0;
++		if (err && (verbose || au_debug_test()))
++			pr_err("%s, err %d\n", name, err);
++		goto out;
++	}
++
++	/* unlock it temporary */
++	h_idst = h_dst->d_inode;
++	mutex_unlock(&h_idst->i_mutex);
++	err = vfsub_setxattr(h_dst, name, *buf, ssz, /*flags*/0);
++	mutex_lock_nested(&h_idst->i_mutex, AuLsc_I_CHILD2);
++	if (unlikely(err)) {
++		if (verbose || au_debug_test())
++			pr_err("%s, err %d\n", name, err);
++		err = au_xattr_ignore(err, name, ignore_flags);
++	}
++
++out:
++	return err;
++}
++
++int au_cpup_xattr(struct dentry *h_dst, struct dentry *h_src, int ignore_flags,
++		  unsigned int verbose)
++{
++	int err, unlocked, acl_access, acl_default;
++	ssize_t ssz;
++	struct inode *h_isrc, *h_idst;
++	char *value, *p, *o, *e;
++
++	/* try stopping to update the source inode while we are referencing */
++	/* there should not be the parent-child relationship between them */
++	h_isrc = h_src->d_inode;
++	h_idst = h_dst->d_inode;
++	mutex_unlock(&h_idst->i_mutex);
++	mutex_lock_nested(&h_isrc->i_mutex, AuLsc_I_CHILD);
++	mutex_lock_nested(&h_idst->i_mutex, AuLsc_I_CHILD2);
++	unlocked = 0;
++
++	/* some filesystems don't list POSIX ACL, for example tmpfs */
++	ssz = vfs_listxattr(h_src, NULL, 0);
++	err = ssz;
++	if (unlikely(err < 0)) {
++		AuTraceErr(err);
++		if (err == -ENODATA
++		    || err == -EOPNOTSUPP)
++			err = 0;	/* ignore */
++		goto out;
++	}
++
++	err = 0;
++	p = NULL;
++	o = NULL;
++	if (ssz) {
++		err = -ENOMEM;
++		p = kmalloc(ssz, GFP_NOFS);
++		o = p;
++		if (unlikely(!p))
++			goto out;
++		err = vfs_listxattr(h_src, p, ssz);
++	}
++	mutex_unlock(&h_isrc->i_mutex);
++	unlocked = 1;
++	AuDbg("err %d, ssz %zd\n", err, ssz);
++	if (unlikely(err < 0))
++		goto out_free;
++
++	err = 0;
++	e = p + ssz;
++	value = NULL;
++	acl_access = 0;
++	acl_default = 0;
++	while (!err && p < e) {
++		acl_access |= !strncmp(p, XATTR_NAME_POSIX_ACL_ACCESS,
++				       sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1);
++		acl_default |= !strncmp(p, XATTR_NAME_POSIX_ACL_DEFAULT,
++					sizeof(XATTR_NAME_POSIX_ACL_DEFAULT)
++					- 1);
++		err = au_do_cpup_xattr(h_dst, h_src, p, &value, ignore_flags,
++				       verbose);
++		p += strlen(p) + 1;
++	}
++	AuTraceErr(err);
++	ignore_flags |= au_xattr_out_of_list;
++	if (!err && !acl_access) {
++		err = au_do_cpup_xattr(h_dst, h_src,
++				       XATTR_NAME_POSIX_ACL_ACCESS, &value,
++				       ignore_flags, verbose);
++		AuTraceErr(err);
++	}
++	if (!err && !acl_default) {
++		err = au_do_cpup_xattr(h_dst, h_src,
++				       XATTR_NAME_POSIX_ACL_DEFAULT, &value,
++				       ignore_flags, verbose);
++		AuTraceErr(err);
++	}
++
++	kfree(value);
++
++out_free:
++	kfree(o);
++out:
++	if (!unlocked)
++		mutex_unlock(&h_isrc->i_mutex);
++	AuTraceErr(err);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++enum {
++	AU_XATTR_LIST,
++	AU_XATTR_GET
++};
++
++struct au_lgxattr {
++	int type;
++	union {
++		struct {
++			char	*list;
++			size_t	size;
++		} list;
++		struct {
++			const char	*name;
++			void		*value;
++			size_t		size;
++		} get;
++	} u;
++};
++
++static ssize_t au_lgxattr(struct dentry *dentry, struct au_lgxattr *arg)
++{
++	ssize_t err;
++	struct path h_path;
++	struct super_block *sb;
++
++	sb = dentry->d_sb;
++	err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
++	if (unlikely(err))
++		goto out;
++	err = au_h_path_getattr(dentry, /*force*/1, &h_path);
++	if (unlikely(err))
++		goto out_si;
++	if (unlikely(!h_path.dentry))
++		/* illegally overlapped or something */
++		goto out_di; /* pretending success */
++
++	/* always topmost entry only */
++	switch (arg->type) {
++	case AU_XATTR_LIST:
++		err = vfs_listxattr(h_path.dentry,
++				    arg->u.list.list, arg->u.list.size);
++		break;
++	case AU_XATTR_GET:
++		err = vfs_getxattr(h_path.dentry,
++				   arg->u.get.name, arg->u.get.value,
++				   arg->u.get.size);
++		break;
++	}
++
++out_di:
++	di_read_unlock(dentry, AuLock_IR);
++out_si:
++	si_read_unlock(sb);
++out:
++	AuTraceErr(err);
++	return err;
++}
++
++ssize_t aufs_listxattr(struct dentry *dentry, char *list, size_t size)
++{
++	struct au_lgxattr arg = {
++		.type = AU_XATTR_LIST,
++		.u.list = {
++			.list	= list,
++			.size	= size
++		},
++	};
++
++	return au_lgxattr(dentry, &arg);
++}
++
++ssize_t aufs_getxattr(struct dentry *dentry, const char *name, void *value,
++		      size_t size)
++{
++	struct au_lgxattr arg = {
++		.type = AU_XATTR_GET,
++		.u.get = {
++			.name	= name,
++			.value	= value,
++			.size	= size
++		},
++	};
++
++	return au_lgxattr(dentry, &arg);
++}
++
++int aufs_setxattr(struct dentry *dentry, const char *name, const void *value,
++		  size_t size, int flags)
++{
++	struct au_srxattr arg = {
++		.type = AU_XATTR_SET,
++		.u.set = {
++			.name	= name,
++			.value	= value,
++			.size	= size,
++			.flags	= flags
++		},
++	};
++
++	return au_srxattr(dentry, &arg);
++}
++
++int aufs_removexattr(struct dentry *dentry, const char *name)
++{
++	struct au_srxattr arg = {
++		.type = AU_XATTR_REMOVE,
++		.u.remove = {
++			.name	= name
++		},
++	};
++
++	return au_srxattr(dentry, &arg);
++}
++
++/* ---------------------------------------------------------------------- */
++
++#if 0
++static size_t au_xattr_list(struct dentry *dentry, char *list, size_t list_size,
++			    const char *name, size_t name_len, int type)
++{
++	return aufs_listxattr(dentry, list, list_size);
++}
++
++static int au_xattr_get(struct dentry *dentry, const char *name, void *buffer,
++			size_t size, int type)
++{
++	return aufs_getxattr(dentry, name, buffer, size);
++}
++
++static int au_xattr_set(struct dentry *dentry, const char *name,
++			const void *value, size_t size, int flags, int type)
++{
++	return aufs_setxattr(dentry, name, value, size, flags);
++}
++
++static const struct xattr_handler au_xattr_handler = {
++	/* no prefix, no flags */
++	.list	= au_xattr_list,
++	.get	= au_xattr_get,
++	.set	= au_xattr_set
++	/* why no remove? */
++};
++
++static const struct xattr_handler *au_xattr_handlers[] = {
++	&au_xattr_handler
++};
++
++void au_xattr_init(struct super_block *sb)
++{
++	/* sb->s_xattr = au_xattr_handlers; */
++}
++#endif
+diff -Nur linux-4.0.4.orig/fs/aufs/xino.c linux-4.0.4/fs/aufs/xino.c
+--- linux-4.0.4.orig/fs/aufs/xino.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/fs/aufs/xino.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,1305 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++/*
++ * external inode number translation table and bitmap
++ */
++
++#include <linux/seq_file.h>
++#include <linux/statfs.h>
++#include "aufs.h"
++
++/* todo: unnecessary to support mmap_sem since kernel-space? */
++ssize_t xino_fread(au_readf_t func, struct file *file, void *kbuf, size_t size,
++		   loff_t *pos)
++{
++	ssize_t err;
++	mm_segment_t oldfs;
++	union {
++		void *k;
++		char __user *u;
++	} buf;
++
++	buf.k = kbuf;
++	oldfs = get_fs();
++	set_fs(KERNEL_DS);
++	do {
++		/* todo: signal_pending? */
++		err = func(file, buf.u, size, pos);
++	} while (err == -EAGAIN || err == -EINTR);
++	set_fs(oldfs);
++
++#if 0 /* reserved for future use */
++	if (err > 0)
++		fsnotify_access(file->f_path.dentry);
++#endif
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static ssize_t do_xino_fwrite(au_writef_t func, struct file *file, void *kbuf,
++			      size_t size, loff_t *pos)
++{
++	ssize_t err;
++	mm_segment_t oldfs;
++	union {
++		void *k;
++		const char __user *u;
++	} buf;
++
++	buf.k = kbuf;
++	oldfs = get_fs();
++	set_fs(KERNEL_DS);
++	do {
++		/* todo: signal_pending? */
++		err = func(file, buf.u, size, pos);
++	} while (err == -EAGAIN || err == -EINTR);
++	set_fs(oldfs);
++
++#if 0 /* reserved for future use */
++	if (err > 0)
++		fsnotify_modify(file->f_path.dentry);
++#endif
++
++	return err;
++}
++
++struct do_xino_fwrite_args {
++	ssize_t *errp;
++	au_writef_t func;
++	struct file *file;
++	void *buf;
++	size_t size;
++	loff_t *pos;
++};
++
++static void call_do_xino_fwrite(void *args)
++{
++	struct do_xino_fwrite_args *a = args;
++	*a->errp = do_xino_fwrite(a->func, a->file, a->buf, a->size, a->pos);
++}
++
++ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
++		    loff_t *pos)
++{
++	ssize_t err;
++
++	/* todo: signal block and no wkq? */
++	if (rlimit(RLIMIT_FSIZE) == RLIM_INFINITY) {
++		lockdep_off();
++		err = do_xino_fwrite(func, file, buf, size, pos);
++		lockdep_on();
++	} else {
++		/*
++		 * it breaks RLIMIT_FSIZE and normal user's limit,
++		 * users should care about quota and real 'filesystem full.'
++		 */
++		int wkq_err;
++		struct do_xino_fwrite_args args = {
++			.errp	= &err,
++			.func	= func,
++			.file	= file,
++			.buf	= buf,
++			.size	= size,
++			.pos	= pos
++		};
++
++		wkq_err = au_wkq_wait(call_do_xino_fwrite, &args);
++		if (unlikely(wkq_err))
++			err = wkq_err;
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * create a new xinofile at the same place/path as @base_file.
++ */
++struct file *au_xino_create2(struct file *base_file, struct file *copy_src)
++{
++	struct file *file;
++	struct dentry *base, *parent;
++	struct inode *dir, *delegated;
++	struct qstr *name;
++	struct path path;
++	int err;
++
++	base = base_file->f_path.dentry;
++	parent = base->d_parent; /* dir inode is locked */
++	dir = parent->d_inode;
++	IMustLock(dir);
++
++	file = ERR_PTR(-EINVAL);
++	name = &base->d_name;
++	path.dentry = vfsub_lookup_one_len(name->name, parent, name->len);
++	if (IS_ERR(path.dentry)) {
++		file = (void *)path.dentry;
++		pr_err("%pd lookup err %ld\n",
++		       base, PTR_ERR(path.dentry));
++		goto out;
++	}
++
++	/* no need to mnt_want_write() since we call dentry_open() later */
++	err = vfs_create(dir, path.dentry, S_IRUGO | S_IWUGO, NULL);
++	if (unlikely(err)) {
++		file = ERR_PTR(err);
++		pr_err("%pd create err %d\n", base, err);
++		goto out_dput;
++	}
++
++	path.mnt = base_file->f_path.mnt;
++	file = vfsub_dentry_open(&path,
++				 O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE
++				 /* | __FMODE_NONOTIFY */);
++	if (IS_ERR(file)) {
++		pr_err("%pd open err %ld\n", base, PTR_ERR(file));
++		goto out_dput;
++	}
++
++	delegated = NULL;
++	err = vfsub_unlink(dir, &file->f_path, &delegated, /*force*/0);
++	if (unlikely(err == -EWOULDBLOCK)) {
++		pr_warn("cannot retry for NFSv4 delegation"
++			" for an internal unlink\n");
++		iput(delegated);
++	}
++	if (unlikely(err)) {
++		pr_err("%pd unlink err %d\n", base, err);
++		goto out_fput;
++	}
++
++	if (copy_src) {
++		/* no one can touch copy_src xino */
++		err = au_copy_file(file, copy_src, vfsub_f_size_read(copy_src));
++		if (unlikely(err)) {
++			pr_err("%pd copy err %d\n", base, err);
++			goto out_fput;
++		}
++	}
++	goto out_dput; /* success */
++
++out_fput:
++	fput(file);
++	file = ERR_PTR(err);
++out_dput:
++	dput(path.dentry);
++out:
++	return file;
++}
++
++struct au_xino_lock_dir {
++	struct au_hinode *hdir;
++	struct dentry *parent;
++	struct mutex *mtx;
++};
++
++static void au_xino_lock_dir(struct super_block *sb, struct file *xino,
++			     struct au_xino_lock_dir *ldir)
++{
++	aufs_bindex_t brid, bindex;
++
++	ldir->hdir = NULL;
++	bindex = -1;
++	brid = au_xino_brid(sb);
++	if (brid >= 0)
++		bindex = au_br_index(sb, brid);
++	if (bindex >= 0) {
++		ldir->hdir = au_hi(sb->s_root->d_inode, bindex);
++		au_hn_imtx_lock_nested(ldir->hdir, AuLsc_I_PARENT);
++	} else {
++		ldir->parent = dget_parent(xino->f_path.dentry);
++		ldir->mtx = &ldir->parent->d_inode->i_mutex;
++		mutex_lock_nested(ldir->mtx, AuLsc_I_PARENT);
++	}
++}
++
++static void au_xino_unlock_dir(struct au_xino_lock_dir *ldir)
++{
++	if (ldir->hdir)
++		au_hn_imtx_unlock(ldir->hdir);
++	else {
++		mutex_unlock(ldir->mtx);
++		dput(ldir->parent);
++	}
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* trucate xino files asynchronously */
++
++int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex)
++{
++	int err;
++	unsigned long jiffy;
++	blkcnt_t blocks;
++	aufs_bindex_t bi, bend;
++	struct kstatfs *st;
++	struct au_branch *br;
++	struct file *new_xino, *file;
++	struct super_block *h_sb;
++	struct au_xino_lock_dir ldir;
++
++	err = -ENOMEM;
++	st = kzalloc(sizeof(*st), GFP_NOFS);
++	if (unlikely(!st))
++		goto out;
++
++	err = -EINVAL;
++	bend = au_sbend(sb);
++	if (unlikely(bindex < 0 || bend < bindex))
++		goto out_st;
++	br = au_sbr(sb, bindex);
++	file = br->br_xino.xi_file;
++	if (!file)
++		goto out_st;
++
++	err = vfs_statfs(&file->f_path, st);
++	if (unlikely(err))
++		AuErr1("statfs err %d, ignored\n", err);
++	jiffy = jiffies;
++	blocks = file_inode(file)->i_blocks;
++	pr_info("begin truncating xino(b%d), ib%llu, %llu/%llu free blks\n",
++		bindex, (u64)blocks, st->f_bfree, st->f_blocks);
++
++	au_xino_lock_dir(sb, file, &ldir);
++	/* mnt_want_write() is unnecessary here */
++	new_xino = au_xino_create2(file, file);
++	au_xino_unlock_dir(&ldir);
++	err = PTR_ERR(new_xino);
++	if (IS_ERR(new_xino)) {
++		pr_err("err %d, ignored\n", err);
++		goto out_st;
++	}
++	err = 0;
++	fput(file);
++	br->br_xino.xi_file = new_xino;
++
++	h_sb = au_br_sb(br);
++	for (bi = 0; bi <= bend; bi++) {
++		if (unlikely(bi == bindex))
++			continue;
++		br = au_sbr(sb, bi);
++		if (au_br_sb(br) != h_sb)
++			continue;
++
++		fput(br->br_xino.xi_file);
++		br->br_xino.xi_file = new_xino;
++		get_file(new_xino);
++	}
++
++	err = vfs_statfs(&new_xino->f_path, st);
++	if (!err) {
++		pr_info("end truncating xino(b%d), ib%llu, %llu/%llu free blks\n",
++			bindex, (u64)file_inode(new_xino)->i_blocks,
++			st->f_bfree, st->f_blocks);
++		if (file_inode(new_xino)->i_blocks < blocks)
++			au_sbi(sb)->si_xino_jiffy = jiffy;
++	} else
++		AuErr1("statfs err %d, ignored\n", err);
++
++out_st:
++	kfree(st);
++out:
++	return err;
++}
++
++struct xino_do_trunc_args {
++	struct super_block *sb;
++	struct au_branch *br;
++};
++
++static void xino_do_trunc(void *_args)
++{
++	struct xino_do_trunc_args *args = _args;
++	struct super_block *sb;
++	struct au_branch *br;
++	struct inode *dir;
++	int err;
++	aufs_bindex_t bindex;
++
++	err = 0;
++	sb = args->sb;
++	dir = sb->s_root->d_inode;
++	br = args->br;
++
++	si_noflush_write_lock(sb);
++	ii_read_lock_parent(dir);
++	bindex = au_br_index(sb, br->br_id);
++	err = au_xino_trunc(sb, bindex);
++	ii_read_unlock(dir);
++	if (unlikely(err))
++		pr_warn("err b%d, (%d)\n", bindex, err);
++	atomic_dec(&br->br_xino_running);
++	atomic_dec(&br->br_count);
++	si_write_unlock(sb);
++	au_nwt_done(&au_sbi(sb)->si_nowait);
++	kfree(args);
++}
++
++static int xino_trunc_test(struct super_block *sb, struct au_branch *br)
++{
++	int err;
++	struct kstatfs st;
++	struct au_sbinfo *sbinfo;
++
++	/* todo: si_xino_expire and the ratio should be customizable */
++	sbinfo = au_sbi(sb);
++	if (time_before(jiffies,
++			sbinfo->si_xino_jiffy + sbinfo->si_xino_expire))
++		return 0;
++
++	/* truncation border */
++	err = vfs_statfs(&br->br_xino.xi_file->f_path, &st);
++	if (unlikely(err)) {
++		AuErr1("statfs err %d, ignored\n", err);
++		return 0;
++	}
++	if (div64_u64(st.f_bfree * 100, st.f_blocks) >= AUFS_XINO_DEF_TRUNC)
++		return 0;
++
++	return 1;
++}
++
++static void xino_try_trunc(struct super_block *sb, struct au_branch *br)
++{
++	struct xino_do_trunc_args *args;
++	int wkq_err;
++
++	if (!xino_trunc_test(sb, br))
++		return;
++
++	if (atomic_inc_return(&br->br_xino_running) > 1)
++		goto out;
++
++	/* lock and kfree() will be called in trunc_xino() */
++	args = kmalloc(sizeof(*args), GFP_NOFS);
++	if (unlikely(!args)) {
++		AuErr1("no memory\n");
++		goto out_args;
++	}
++
++	atomic_inc(&br->br_count);
++	args->sb = sb;
++	args->br = br;
++	wkq_err = au_wkq_nowait(xino_do_trunc, args, sb, /*flags*/0);
++	if (!wkq_err)
++		return; /* success */
++
++	pr_err("wkq %d\n", wkq_err);
++	atomic_dec(&br->br_count);
++
++out_args:
++	kfree(args);
++out:
++	atomic_dec(&br->br_xino_running);
++}
++
++/* ---------------------------------------------------------------------- */
++
++static int au_xino_do_write(au_writef_t write, struct file *file,
++			    ino_t h_ino, ino_t ino)
++{
++	loff_t pos;
++	ssize_t sz;
++
++	pos = h_ino;
++	if (unlikely(au_loff_max / sizeof(ino) - 1 < pos)) {
++		AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
++		return -EFBIG;
++	}
++	pos *= sizeof(ino);
++	sz = xino_fwrite(write, file, &ino, sizeof(ino), &pos);
++	if (sz == sizeof(ino))
++		return 0; /* success */
++
++	AuIOErr("write failed (%zd)\n", sz);
++	return -EIO;
++}
++
++/*
++ * write @ino to the xinofile for the specified branch{@sb, @bindex}
++ * at the position of @h_ino.
++ * even if @ino is zero, it is written to the xinofile and means no entry.
++ * if the size of the xino file on a specific filesystem exceeds the watermark,
++ * try truncating it.
++ */
++int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		  ino_t ino)
++{
++	int err;
++	unsigned int mnt_flags;
++	struct au_branch *br;
++
++	BUILD_BUG_ON(sizeof(long long) != sizeof(au_loff_max)
++		     || ((loff_t)-1) > 0);
++	SiMustAnyLock(sb);
++
++	mnt_flags = au_mntflags(sb);
++	if (!au_opt_test(mnt_flags, XINO))
++		return 0;
++
++	br = au_sbr(sb, bindex);
++	err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
++			       h_ino, ino);
++	if (!err) {
++		if (au_opt_test(mnt_flags, TRUNC_XINO)
++		    && au_test_fs_trunc_xino(au_br_sb(br)))
++			xino_try_trunc(sb, br);
++		return 0; /* success */
++	}
++
++	AuIOErr("write failed (%d)\n", err);
++	return -EIO;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* aufs inode number bitmap */
++
++static const int page_bits = (int)PAGE_SIZE * BITS_PER_BYTE;
++static ino_t xib_calc_ino(unsigned long pindex, int bit)
++{
++	ino_t ino;
++
++	AuDebugOn(bit < 0 || page_bits <= bit);
++	ino = AUFS_FIRST_INO + pindex * page_bits + bit;
++	return ino;
++}
++
++static void xib_calc_bit(ino_t ino, unsigned long *pindex, int *bit)
++{
++	AuDebugOn(ino < AUFS_FIRST_INO);
++	ino -= AUFS_FIRST_INO;
++	*pindex = ino / page_bits;
++	*bit = ino % page_bits;
++}
++
++static int xib_pindex(struct super_block *sb, unsigned long pindex)
++{
++	int err;
++	loff_t pos;
++	ssize_t sz;
++	struct au_sbinfo *sbinfo;
++	struct file *xib;
++	unsigned long *p;
++
++	sbinfo = au_sbi(sb);
++	MtxMustLock(&sbinfo->si_xib_mtx);
++	AuDebugOn(pindex > ULONG_MAX / PAGE_SIZE
++		  || !au_opt_test(sbinfo->si_mntflags, XINO));
++
++	if (pindex == sbinfo->si_xib_last_pindex)
++		return 0;
++
++	xib = sbinfo->si_xib;
++	p = sbinfo->si_xib_buf;
++	pos = sbinfo->si_xib_last_pindex;
++	pos *= PAGE_SIZE;
++	sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
++	if (unlikely(sz != PAGE_SIZE))
++		goto out;
++
++	pos = pindex;
++	pos *= PAGE_SIZE;
++	if (vfsub_f_size_read(xib) >= pos + PAGE_SIZE)
++		sz = xino_fread(sbinfo->si_xread, xib, p, PAGE_SIZE, &pos);
++	else {
++		memset(p, 0, PAGE_SIZE);
++		sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
++	}
++	if (sz == PAGE_SIZE) {
++		sbinfo->si_xib_last_pindex = pindex;
++		return 0; /* success */
++	}
++
++out:
++	AuIOErr1("write failed (%zd)\n", sz);
++	err = sz;
++	if (sz >= 0)
++		err = -EIO;
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++static void au_xib_clear_bit(struct inode *inode)
++{
++	int err, bit;
++	unsigned long pindex;
++	struct super_block *sb;
++	struct au_sbinfo *sbinfo;
++
++	AuDebugOn(inode->i_nlink);
++
++	sb = inode->i_sb;
++	xib_calc_bit(inode->i_ino, &pindex, &bit);
++	AuDebugOn(page_bits <= bit);
++	sbinfo = au_sbi(sb);
++	mutex_lock(&sbinfo->si_xib_mtx);
++	err = xib_pindex(sb, pindex);
++	if (!err) {
++		clear_bit(bit, sbinfo->si_xib_buf);
++		sbinfo->si_xib_next_bit = bit;
++	}
++	mutex_unlock(&sbinfo->si_xib_mtx);
++}
++
++/* for s_op->delete_inode() */
++void au_xino_delete_inode(struct inode *inode, const int unlinked)
++{
++	int err;
++	unsigned int mnt_flags;
++	aufs_bindex_t bindex, bend, bi;
++	unsigned char try_trunc;
++	struct au_iinfo *iinfo;
++	struct super_block *sb;
++	struct au_hinode *hi;
++	struct inode *h_inode;
++	struct au_branch *br;
++	au_writef_t xwrite;
++
++	sb = inode->i_sb;
++	mnt_flags = au_mntflags(sb);
++	if (!au_opt_test(mnt_flags, XINO)
++	    || inode->i_ino == AUFS_ROOT_INO)
++		return;
++
++	if (unlinked) {
++		au_xigen_inc(inode);
++		au_xib_clear_bit(inode);
++	}
++
++	iinfo = au_ii(inode);
++	if (!iinfo)
++		return;
++
++	bindex = iinfo->ii_bstart;
++	if (bindex < 0)
++		return;
++
++	xwrite = au_sbi(sb)->si_xwrite;
++	try_trunc = !!au_opt_test(mnt_flags, TRUNC_XINO);
++	hi = iinfo->ii_hinode + bindex;
++	bend = iinfo->ii_bend;
++	for (; bindex <= bend; bindex++, hi++) {
++		h_inode = hi->hi_inode;
++		if (!h_inode
++		    || (!unlinked && h_inode->i_nlink))
++			continue;
++
++		/* inode may not be revalidated */
++		bi = au_br_index(sb, hi->hi_id);
++		if (bi < 0)
++			continue;
++
++		br = au_sbr(sb, bi);
++		err = au_xino_do_write(xwrite, br->br_xino.xi_file,
++				       h_inode->i_ino, /*ino*/0);
++		if (!err && try_trunc
++		    && au_test_fs_trunc_xino(au_br_sb(br)))
++			xino_try_trunc(sb, br);
++	}
++}
++
++/* get an unused inode number from bitmap */
++ino_t au_xino_new_ino(struct super_block *sb)
++{
++	ino_t ino;
++	unsigned long *p, pindex, ul, pend;
++	struct au_sbinfo *sbinfo;
++	struct file *file;
++	int free_bit, err;
++
++	if (!au_opt_test(au_mntflags(sb), XINO))
++		return iunique(sb, AUFS_FIRST_INO);
++
++	sbinfo = au_sbi(sb);
++	mutex_lock(&sbinfo->si_xib_mtx);
++	p = sbinfo->si_xib_buf;
++	free_bit = sbinfo->si_xib_next_bit;
++	if (free_bit < page_bits && !test_bit(free_bit, p))
++		goto out; /* success */
++	free_bit = find_first_zero_bit(p, page_bits);
++	if (free_bit < page_bits)
++		goto out; /* success */
++
++	pindex = sbinfo->si_xib_last_pindex;
++	for (ul = pindex - 1; ul < ULONG_MAX; ul--) {
++		err = xib_pindex(sb, ul);
++		if (unlikely(err))
++			goto out_err;
++		free_bit = find_first_zero_bit(p, page_bits);
++		if (free_bit < page_bits)
++			goto out; /* success */
++	}
++
++	file = sbinfo->si_xib;
++	pend = vfsub_f_size_read(file) / PAGE_SIZE;
++	for (ul = pindex + 1; ul <= pend; ul++) {
++		err = xib_pindex(sb, ul);
++		if (unlikely(err))
++			goto out_err;
++		free_bit = find_first_zero_bit(p, page_bits);
++		if (free_bit < page_bits)
++			goto out; /* success */
++	}
++	BUG();
++
++out:
++	set_bit(free_bit, p);
++	sbinfo->si_xib_next_bit = free_bit + 1;
++	pindex = sbinfo->si_xib_last_pindex;
++	mutex_unlock(&sbinfo->si_xib_mtx);
++	ino = xib_calc_ino(pindex, free_bit);
++	AuDbg("i%lu\n", (unsigned long)ino);
++	return ino;
++out_err:
++	mutex_unlock(&sbinfo->si_xib_mtx);
++	AuDbg("i0\n");
++	return 0;
++}
++
++/*
++ * read @ino from xinofile for the specified branch{@sb, @bindex}
++ * at the position of @h_ino.
++ * if @ino does not exist and @do_new is true, get new one.
++ */
++int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
++		 ino_t *ino)
++{
++	int err;
++	ssize_t sz;
++	loff_t pos;
++	struct file *file;
++	struct au_sbinfo *sbinfo;
++
++	*ino = 0;
++	if (!au_opt_test(au_mntflags(sb), XINO))
++		return 0; /* no xino */
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	pos = h_ino;
++	if (unlikely(au_loff_max / sizeof(*ino) - 1 < pos)) {
++		AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
++		return -EFBIG;
++	}
++	pos *= sizeof(*ino);
++
++	file = au_sbr(sb, bindex)->br_xino.xi_file;
++	if (vfsub_f_size_read(file) < pos + sizeof(*ino))
++		return 0; /* no ino */
++
++	sz = xino_fread(sbinfo->si_xread, file, ino, sizeof(*ino), &pos);
++	if (sz == sizeof(*ino))
++		return 0; /* success */
++
++	err = sz;
++	if (unlikely(sz >= 0)) {
++		err = -EIO;
++		AuIOErr("xino read error (%zd)\n", sz);
++	}
++
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* create and set a new xino file */
++
++struct file *au_xino_create(struct super_block *sb, char *fname, int silent)
++{
++	struct file *file;
++	struct dentry *h_parent, *d;
++	struct inode *h_dir;
++	int err;
++
++	/*
++	 * at mount-time, and the xino file is the default path,
++	 * hnotify is disabled so we have no notify events to ignore.
++	 * when a user specified the xino, we cannot get au_hdir to be ignored.
++	 */
++	file = vfsub_filp_open(fname, O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE
++			       /* | __FMODE_NONOTIFY */,
++			       S_IRUGO | S_IWUGO);
++	if (IS_ERR(file)) {
++		if (!silent)
++			pr_err("open %s(%ld)\n", fname, PTR_ERR(file));
++		return file;
++	}
++
++	/* keep file count */
++	h_parent = dget_parent(file->f_path.dentry);
++	h_dir = h_parent->d_inode;
++	mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
++	/* mnt_want_write() is unnecessary here */
++	/* no delegation since it is just created */
++	err = vfsub_unlink(h_dir, &file->f_path, /*delegated*/NULL, /*force*/0);
++	mutex_unlock(&h_dir->i_mutex);
++	dput(h_parent);
++	if (unlikely(err)) {
++		if (!silent)
++			pr_err("unlink %s(%d)\n", fname, err);
++		goto out;
++	}
++
++	err = -EINVAL;
++	d = file->f_path.dentry;
++	if (unlikely(sb == d->d_sb)) {
++		if (!silent)
++			pr_err("%s must be outside\n", fname);
++		goto out;
++	}
++	if (unlikely(au_test_fs_bad_xino(d->d_sb))) {
++		if (!silent)
++			pr_err("xino doesn't support %s(%s)\n",
++			       fname, au_sbtype(d->d_sb));
++		goto out;
++	}
++	return file; /* success */
++
++out:
++	fput(file);
++	file = ERR_PTR(err);
++	return file;
++}
++
++/*
++ * find another branch who is on the same filesystem of the specified
++ * branch{@btgt}. search until @bend.
++ */
++static int is_sb_shared(struct super_block *sb, aufs_bindex_t btgt,
++			aufs_bindex_t bend)
++{
++	aufs_bindex_t bindex;
++	struct super_block *tgt_sb = au_sbr_sb(sb, btgt);
++
++	for (bindex = 0; bindex < btgt; bindex++)
++		if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
++			return bindex;
++	for (bindex++; bindex <= bend; bindex++)
++		if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
++			return bindex;
++	return -1;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * initialize the xinofile for the specified branch @br
++ * at the place/path where @base_file indicates.
++ * test whether another branch is on the same filesystem or not,
++ * if @do_test is true.
++ */
++int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t h_ino,
++	       struct file *base_file, int do_test)
++{
++	int err;
++	ino_t ino;
++	aufs_bindex_t bend, bindex;
++	struct au_branch *shared_br, *b;
++	struct file *file;
++	struct super_block *tgt_sb;
++
++	shared_br = NULL;
++	bend = au_sbend(sb);
++	if (do_test) {
++		tgt_sb = au_br_sb(br);
++		for (bindex = 0; bindex <= bend; bindex++) {
++			b = au_sbr(sb, bindex);
++			if (tgt_sb == au_br_sb(b)) {
++				shared_br = b;
++				break;
++			}
++		}
++	}
++
++	if (!shared_br || !shared_br->br_xino.xi_file) {
++		struct au_xino_lock_dir ldir;
++
++		au_xino_lock_dir(sb, base_file, &ldir);
++		/* mnt_want_write() is unnecessary here */
++		file = au_xino_create2(base_file, NULL);
++		au_xino_unlock_dir(&ldir);
++		err = PTR_ERR(file);
++		if (IS_ERR(file))
++			goto out;
++		br->br_xino.xi_file = file;
++	} else {
++		br->br_xino.xi_file = shared_br->br_xino.xi_file;
++		get_file(br->br_xino.xi_file);
++	}
++
++	ino = AUFS_ROOT_INO;
++	err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
++			       h_ino, ino);
++	if (unlikely(err)) {
++		fput(br->br_xino.xi_file);
++		br->br_xino.xi_file = NULL;
++	}
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* trucate a xino bitmap file */
++
++/* todo: slow */
++static int do_xib_restore(struct super_block *sb, struct file *file, void *page)
++{
++	int err, bit;
++	ssize_t sz;
++	unsigned long pindex;
++	loff_t pos, pend;
++	struct au_sbinfo *sbinfo;
++	au_readf_t func;
++	ino_t *ino;
++	unsigned long *p;
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	MtxMustLock(&sbinfo->si_xib_mtx);
++	p = sbinfo->si_xib_buf;
++	func = sbinfo->si_xread;
++	pend = vfsub_f_size_read(file);
++	pos = 0;
++	while (pos < pend) {
++		sz = xino_fread(func, file, page, PAGE_SIZE, &pos);
++		err = sz;
++		if (unlikely(sz <= 0))
++			goto out;
++
++		err = 0;
++		for (ino = page; sz > 0; ino++, sz -= sizeof(ino)) {
++			if (unlikely(*ino < AUFS_FIRST_INO))
++				continue;
++
++			xib_calc_bit(*ino, &pindex, &bit);
++			AuDebugOn(page_bits <= bit);
++			err = xib_pindex(sb, pindex);
++			if (!err)
++				set_bit(bit, p);
++			else
++				goto out;
++		}
++	}
++
++out:
++	return err;
++}
++
++static int xib_restore(struct super_block *sb)
++{
++	int err;
++	aufs_bindex_t bindex, bend;
++	void *page;
++
++	err = -ENOMEM;
++	page = (void *)__get_free_page(GFP_NOFS);
++	if (unlikely(!page))
++		goto out;
++
++	err = 0;
++	bend = au_sbend(sb);
++	for (bindex = 0; !err && bindex <= bend; bindex++)
++		if (!bindex || is_sb_shared(sb, bindex, bindex - 1) < 0)
++			err = do_xib_restore
++				(sb, au_sbr(sb, bindex)->br_xino.xi_file, page);
++		else
++			AuDbg("b%d\n", bindex);
++	free_page((unsigned long)page);
++
++out:
++	return err;
++}
++
++int au_xib_trunc(struct super_block *sb)
++{
++	int err;
++	ssize_t sz;
++	loff_t pos;
++	struct au_xino_lock_dir ldir;
++	struct au_sbinfo *sbinfo;
++	unsigned long *p;
++	struct file *file;
++
++	SiMustWriteLock(sb);
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	if (!au_opt_test(sbinfo->si_mntflags, XINO))
++		goto out;
++
++	file = sbinfo->si_xib;
++	if (vfsub_f_size_read(file) <= PAGE_SIZE)
++		goto out;
++
++	au_xino_lock_dir(sb, file, &ldir);
++	/* mnt_want_write() is unnecessary here */
++	file = au_xino_create2(sbinfo->si_xib, NULL);
++	au_xino_unlock_dir(&ldir);
++	err = PTR_ERR(file);
++	if (IS_ERR(file))
++		goto out;
++	fput(sbinfo->si_xib);
++	sbinfo->si_xib = file;
++
++	p = sbinfo->si_xib_buf;
++	memset(p, 0, PAGE_SIZE);
++	pos = 0;
++	sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xib, p, PAGE_SIZE, &pos);
++	if (unlikely(sz != PAGE_SIZE)) {
++		err = sz;
++		AuIOErr("err %d\n", err);
++		if (sz >= 0)
++			err = -EIO;
++		goto out;
++	}
++
++	mutex_lock(&sbinfo->si_xib_mtx);
++	/* mnt_want_write() is unnecessary here */
++	err = xib_restore(sb);
++	mutex_unlock(&sbinfo->si_xib_mtx);
++
++out:
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * xino mount option handlers
++ */
++static au_readf_t find_readf(struct file *h_file)
++{
++	const struct file_operations *fop = h_file->f_op;
++
++	if (fop->read)
++		return fop->read;
++	if (fop->aio_read)
++		return do_sync_read;
++	if (fop->read_iter)
++		return new_sync_read;
++	return ERR_PTR(-ENOSYS);
++}
++
++static au_writef_t find_writef(struct file *h_file)
++{
++	const struct file_operations *fop = h_file->f_op;
++
++	if (fop->write)
++		return fop->write;
++	if (fop->aio_write)
++		return do_sync_write;
++	if (fop->write_iter)
++		return new_sync_write;
++	return ERR_PTR(-ENOSYS);
++}
++
++/* xino bitmap */
++static void xino_clear_xib(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	SiMustWriteLock(sb);
++
++	sbinfo = au_sbi(sb);
++	sbinfo->si_xread = NULL;
++	sbinfo->si_xwrite = NULL;
++	if (sbinfo->si_xib)
++		fput(sbinfo->si_xib);
++	sbinfo->si_xib = NULL;
++	free_page((unsigned long)sbinfo->si_xib_buf);
++	sbinfo->si_xib_buf = NULL;
++}
++
++static int au_xino_set_xib(struct super_block *sb, struct file *base)
++{
++	int err;
++	loff_t pos;
++	struct au_sbinfo *sbinfo;
++	struct file *file;
++
++	SiMustWriteLock(sb);
++
++	sbinfo = au_sbi(sb);
++	file = au_xino_create2(base, sbinfo->si_xib);
++	err = PTR_ERR(file);
++	if (IS_ERR(file))
++		goto out;
++	if (sbinfo->si_xib)
++		fput(sbinfo->si_xib);
++	sbinfo->si_xib = file;
++	sbinfo->si_xread = find_readf(file);
++	sbinfo->si_xwrite = find_writef(file);
++
++	err = -ENOMEM;
++	if (!sbinfo->si_xib_buf)
++		sbinfo->si_xib_buf = (void *)get_zeroed_page(GFP_NOFS);
++	if (unlikely(!sbinfo->si_xib_buf))
++		goto out_unset;
++
++	sbinfo->si_xib_last_pindex = 0;
++	sbinfo->si_xib_next_bit = 0;
++	if (vfsub_f_size_read(file) < PAGE_SIZE) {
++		pos = 0;
++		err = xino_fwrite(sbinfo->si_xwrite, file, sbinfo->si_xib_buf,
++				  PAGE_SIZE, &pos);
++		if (unlikely(err != PAGE_SIZE))
++			goto out_free;
++	}
++	err = 0;
++	goto out; /* success */
++
++out_free:
++	free_page((unsigned long)sbinfo->si_xib_buf);
++	sbinfo->si_xib_buf = NULL;
++	if (err >= 0)
++		err = -EIO;
++out_unset:
++	fput(sbinfo->si_xib);
++	sbinfo->si_xib = NULL;
++	sbinfo->si_xread = NULL;
++	sbinfo->si_xwrite = NULL;
++out:
++	return err;
++}
++
++/* xino for each branch */
++static void xino_clear_br(struct super_block *sb)
++{
++	aufs_bindex_t bindex, bend;
++	struct au_branch *br;
++
++	bend = au_sbend(sb);
++	for (bindex = 0; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		if (!br || !br->br_xino.xi_file)
++			continue;
++
++		fput(br->br_xino.xi_file);
++		br->br_xino.xi_file = NULL;
++	}
++}
++
++static int au_xino_set_br(struct super_block *sb, struct file *base)
++{
++	int err;
++	ino_t ino;
++	aufs_bindex_t bindex, bend, bshared;
++	struct {
++		struct file *old, *new;
++	} *fpair, *p;
++	struct au_branch *br;
++	struct inode *inode;
++	au_writef_t writef;
++
++	SiMustWriteLock(sb);
++
++	err = -ENOMEM;
++	bend = au_sbend(sb);
++	fpair = kcalloc(bend + 1, sizeof(*fpair), GFP_NOFS);
++	if (unlikely(!fpair))
++		goto out;
++
++	inode = sb->s_root->d_inode;
++	ino = AUFS_ROOT_INO;
++	writef = au_sbi(sb)->si_xwrite;
++	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
++		br = au_sbr(sb, bindex);
++		bshared = is_sb_shared(sb, bindex, bindex - 1);
++		if (bshared >= 0) {
++			/* shared xino */
++			*p = fpair[bshared];
++			get_file(p->new);
++		}
++
++		if (!p->new) {
++			/* new xino */
++			p->old = br->br_xino.xi_file;
++			p->new = au_xino_create2(base, br->br_xino.xi_file);
++			err = PTR_ERR(p->new);
++			if (IS_ERR(p->new)) {
++				p->new = NULL;
++				goto out_pair;
++			}
++		}
++
++		err = au_xino_do_write(writef, p->new,
++				       au_h_iptr(inode, bindex)->i_ino, ino);
++		if (unlikely(err))
++			goto out_pair;
++	}
++
++	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
++		br = au_sbr(sb, bindex);
++		if (br->br_xino.xi_file)
++			fput(br->br_xino.xi_file);
++		get_file(p->new);
++		br->br_xino.xi_file = p->new;
++	}
++
++out_pair:
++	for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++)
++		if (p->new)
++			fput(p->new);
++		else
++			break;
++	kfree(fpair);
++out:
++	return err;
++}
++
++void au_xino_clr(struct super_block *sb)
++{
++	struct au_sbinfo *sbinfo;
++
++	au_xigen_clr(sb);
++	xino_clear_xib(sb);
++	xino_clear_br(sb);
++	sbinfo = au_sbi(sb);
++	/* lvalue, do not call au_mntflags() */
++	au_opt_clr(sbinfo->si_mntflags, XINO);
++}
++
++int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount)
++{
++	int err, skip;
++	struct dentry *parent, *cur_parent;
++	struct qstr *dname, *cur_name;
++	struct file *cur_xino;
++	struct inode *dir;
++	struct au_sbinfo *sbinfo;
++
++	SiMustWriteLock(sb);
++
++	err = 0;
++	sbinfo = au_sbi(sb);
++	parent = dget_parent(xino->file->f_path.dentry);
++	if (remount) {
++		skip = 0;
++		dname = &xino->file->f_path.dentry->d_name;
++		cur_xino = sbinfo->si_xib;
++		if (cur_xino) {
++			cur_parent = dget_parent(cur_xino->f_path.dentry);
++			cur_name = &cur_xino->f_path.dentry->d_name;
++			skip = (cur_parent == parent
++				&& au_qstreq(dname, cur_name));
++			dput(cur_parent);
++		}
++		if (skip)
++			goto out;
++	}
++
++	au_opt_set(sbinfo->si_mntflags, XINO);
++	dir = parent->d_inode;
++	mutex_lock_nested(&dir->i_mutex, AuLsc_I_PARENT);
++	/* mnt_want_write() is unnecessary here */
++	err = au_xino_set_xib(sb, xino->file);
++	if (!err)
++		err = au_xigen_set(sb, xino->file);
++	if (!err)
++		err = au_xino_set_br(sb, xino->file);
++	mutex_unlock(&dir->i_mutex);
++	if (!err)
++		goto out; /* success */
++
++	/* reset all */
++	AuIOErr("failed creating xino(%d).\n", err);
++	au_xigen_clr(sb);
++	xino_clear_xib(sb);
++
++out:
++	dput(parent);
++	return err;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/*
++ * create a xinofile at the default place/path.
++ */
++struct file *au_xino_def(struct super_block *sb)
++{
++	struct file *file;
++	char *page, *p;
++	struct au_branch *br;
++	struct super_block *h_sb;
++	struct path path;
++	aufs_bindex_t bend, bindex, bwr;
++
++	br = NULL;
++	bend = au_sbend(sb);
++	bwr = -1;
++	for (bindex = 0; bindex <= bend; bindex++) {
++		br = au_sbr(sb, bindex);
++		if (au_br_writable(br->br_perm)
++		    && !au_test_fs_bad_xino(au_br_sb(br))) {
++			bwr = bindex;
++			break;
++		}
++	}
++
++	if (bwr >= 0) {
++		file = ERR_PTR(-ENOMEM);
++		page = (void *)__get_free_page(GFP_NOFS);
++		if (unlikely(!page))
++			goto out;
++		path.mnt = au_br_mnt(br);
++		path.dentry = au_h_dptr(sb->s_root, bwr);
++		p = d_path(&path, page, PATH_MAX - sizeof(AUFS_XINO_FNAME));
++		file = (void *)p;
++		if (!IS_ERR(p)) {
++			strcat(p, "/" AUFS_XINO_FNAME);
++			AuDbg("%s\n", p);
++			file = au_xino_create(sb, p, /*silent*/0);
++			if (!IS_ERR(file))
++				au_xino_brid_set(sb, br->br_id);
++		}
++		free_page((unsigned long)page);
++	} else {
++		file = au_xino_create(sb, AUFS_XINO_DEFPATH, /*silent*/0);
++		if (IS_ERR(file))
++			goto out;
++		h_sb = file->f_path.dentry->d_sb;
++		if (unlikely(au_test_fs_bad_xino(h_sb))) {
++			pr_err("xino doesn't support %s(%s)\n",
++			       AUFS_XINO_DEFPATH, au_sbtype(h_sb));
++			fput(file);
++			file = ERR_PTR(-EINVAL);
++		}
++		if (!IS_ERR(file))
++			au_xino_brid_set(sb, -1);
++	}
++
++out:
++	return file;
++}
++
++/* ---------------------------------------------------------------------- */
++
++int au_xino_path(struct seq_file *seq, struct file *file)
++{
++	int err;
++
++	err = au_seq_path(seq, &file->f_path);
++	if (unlikely(err < 0))
++		goto out;
++
++	err = 0;
++#define Deleted "\\040(deleted)"
++	seq->count -= sizeof(Deleted) - 1;
++	AuDebugOn(memcmp(seq->buf + seq->count, Deleted,
++			 sizeof(Deleted) - 1));
++#undef Deleted
++
++out:
++	return err;
++}
+diff -Nur linux-4.0.4.orig/fs/buffer.c linux-4.0.4/fs/buffer.c
+--- linux-4.0.4.orig/fs/buffer.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/buffer.c	2015-05-30 22:11:30.000000000 +0200
+@@ -2450,7 +2450,7 @@
+ 	 * Update file times before taking page lock. We may end up failing the
+ 	 * fault so this update may be superfluous but who really cares...
+ 	 */
+-	file_update_time(vma->vm_file);
++	vma_file_update_time(vma);
+ 
+ 	ret = __block_page_mkwrite(vma, vmf, get_block);
+ 	sb_end_pagefault(sb);
+diff -Nur linux-4.0.4.orig/fs/dcache.c linux-4.0.4/fs/dcache.c
+--- linux-4.0.4.orig/fs/dcache.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/dcache.c	2015-05-30 22:11:30.000000000 +0200
+@@ -1130,7 +1130,7 @@
+  *
+  * The @enter() and @finish() callbacks are called with d_lock held.
+  */
+-static void d_walk(struct dentry *parent, void *data,
++void d_walk(struct dentry *parent, void *data,
+ 		   enum d_walk_ret (*enter)(void *, struct dentry *),
+ 		   void (*finish)(void *))
+ {
+diff -Nur linux-4.0.4.orig/fs/Kconfig linux-4.0.4/fs/Kconfig
+--- linux-4.0.4.orig/fs/Kconfig	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/Kconfig	2015-05-30 22:11:31.000000000 +0200
+@@ -218,6 +218,7 @@
+ source "fs/ufs/Kconfig"
+ source "fs/exofs/Kconfig"
+ source "fs/f2fs/Kconfig"
++source "fs/aufs/Kconfig"
+ 
+ endif # MISC_FILESYSTEMS
+ 
+diff -Nur linux-4.0.4.orig/fs/Makefile linux-4.0.4/fs/Makefile
+--- linux-4.0.4.orig/fs/Makefile	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/Makefile	2015-05-30 22:11:31.000000000 +0200
+@@ -126,3 +126,4 @@
+ obj-$(CONFIG_CEPH_FS)		+= ceph/
+ obj-$(CONFIG_PSTORE)		+= pstore/
+ obj-$(CONFIG_EFIVAR_FS)		+= efivarfs/
++obj-$(CONFIG_AUFS_FS)           += aufs/
+diff -Nur linux-4.0.4.orig/fs/proc/base.c linux-4.0.4/fs/proc/base.c
+--- linux-4.0.4.orig/fs/proc/base.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/proc/base.c	2015-05-30 22:11:30.000000000 +0200
+@@ -1735,7 +1735,7 @@
+ 	down_read(&mm->mmap_sem);
+ 	vma = find_exact_vma(mm, vm_start, vm_end);
+ 	if (vma && vma->vm_file) {
+-		*path = vma->vm_file->f_path;
++		*path = vma_pr_or_file(vma)->f_path;
+ 		path_get(path);
+ 		rc = 0;
+ 	}
+diff -Nur linux-4.0.4.orig/fs/proc/nommu.c linux-4.0.4/fs/proc/nommu.c
+--- linux-4.0.4.orig/fs/proc/nommu.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/proc/nommu.c	2015-05-30 22:11:30.000000000 +0200
+@@ -45,7 +45,10 @@
+ 	file = region->vm_file;
+ 
+ 	if (file) {
+-		struct inode *inode = file_inode(region->vm_file);
++		struct inode *inode;
++
++		file = vmr_pr_or_file(region);
++		inode = file_inode(file);
+ 		dev = inode->i_sb->s_dev;
+ 		ino = inode->i_ino;
+ 	}
+diff -Nur linux-4.0.4.orig/fs/proc/task_mmu.c linux-4.0.4/fs/proc/task_mmu.c
+--- linux-4.0.4.orig/fs/proc/task_mmu.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/proc/task_mmu.c	2015-05-30 22:11:30.000000000 +0200
+@@ -279,7 +279,10 @@
+ 	const char *name = NULL;
+ 
+ 	if (file) {
+-		struct inode *inode = file_inode(vma->vm_file);
++		struct inode *inode;
++
++		file = vma_pr_or_file(vma);
++		inode = file_inode(file);
+ 		dev = inode->i_sb->s_dev;
+ 		ino = inode->i_ino;
+ 		pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
+@@ -1479,7 +1482,7 @@
+ 	struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
+ 	struct vm_area_struct *vma = v;
+ 	struct numa_maps *md = &numa_priv->md;
+-	struct file *file = vma->vm_file;
++	struct file *file = vma_pr_or_file(vma);
+ 	struct mm_struct *mm = vma->vm_mm;
+ 	struct mm_walk walk = {
+ 		.hugetlb_entry = gather_hugetlb_stats,
+diff -Nur linux-4.0.4.orig/fs/proc/task_nommu.c linux-4.0.4/fs/proc/task_nommu.c
+--- linux-4.0.4.orig/fs/proc/task_nommu.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/proc/task_nommu.c	2015-05-30 22:11:30.000000000 +0200
+@@ -160,7 +160,10 @@
+ 	file = vma->vm_file;
+ 
+ 	if (file) {
+-		struct inode *inode = file_inode(vma->vm_file);
++		struct inode *inode;
++
++		file = vma_pr_or_file(file);
++		inode = file_inode(file);
+ 		dev = inode->i_sb->s_dev;
+ 		ino = inode->i_ino;
+ 		pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
+diff -Nur linux-4.0.4.orig/fs/splice.c linux-4.0.4/fs/splice.c
+--- linux-4.0.4.orig/fs/splice.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/fs/splice.c	2015-05-30 22:11:30.000000000 +0200
+@@ -1099,8 +1099,8 @@
+ /*
+  * Attempt to initiate a splice from pipe to file.
+  */
+-static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
+-			   loff_t *ppos, size_t len, unsigned int flags)
++long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
++		    loff_t *ppos, size_t len, unsigned int flags)
+ {
+ 	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *,
+ 				loff_t *, size_t, unsigned int);
+@@ -1116,9 +1116,9 @@
+ /*
+  * Attempt to initiate a splice from a file to a pipe.
+  */
+-static long do_splice_to(struct file *in, loff_t *ppos,
+-			 struct pipe_inode_info *pipe, size_t len,
+-			 unsigned int flags)
++long do_splice_to(struct file *in, loff_t *ppos,
++		  struct pipe_inode_info *pipe, size_t len,
++		  unsigned int flags)
+ {
+ 	ssize_t (*splice_read)(struct file *, loff_t *,
+ 			       struct pipe_inode_info *, size_t, unsigned int);
+diff -Nur linux-4.0.4.orig/include/linux/file.h linux-4.0.4/include/linux/file.h
+--- linux-4.0.4.orig/include/linux/file.h	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/include/linux/file.h	2015-05-30 22:11:31.000000000 +0200
+@@ -19,6 +19,7 @@
+ struct path;
+ extern struct file *alloc_file(struct path *, fmode_t mode,
+ 	const struct file_operations *fop);
++extern struct file *get_empty_filp(void);
+ 
+ static inline void fput_light(struct file *file, int fput_needed)
+ {
+diff -Nur linux-4.0.4.orig/include/linux/mm.h linux-4.0.4/include/linux/mm.h
+--- linux-4.0.4.orig/include/linux/mm.h	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/include/linux/mm.h	2015-05-30 22:11:30.000000000 +0200
+@@ -1254,6 +1254,28 @@
+ }
+ #endif
+ 
++#ifdef CONFIG_MMU
++extern void vma_do_file_update_time(struct vm_area_struct *, const char[], int);
++extern struct file *vma_do_pr_or_file(struct vm_area_struct *, const char[],
++				      int);
++extern void vma_do_get_file(struct vm_area_struct *, const char[], int);
++extern void vma_do_fput(struct vm_area_struct *, const char[], int);
++
++#define vma_file_update_time(vma)	vma_do_file_update_time(vma, __func__, \
++								__LINE__)
++#define vma_pr_or_file(vma)		vma_do_pr_or_file(vma, __func__, \
++							  __LINE__)
++#define vma_get_file(vma)		vma_do_get_file(vma, __func__, __LINE__)
++#define vma_fput(vma)			vma_do_fput(vma, __func__, __LINE__)
++#else
++extern struct file *vmr_do_pr_or_file(struct vm_region *, const char[], int);
++extern void vmr_do_fput(struct vm_region *, const char[], int);
++
++#define vmr_pr_or_file(region)		vmr_do_pr_or_file(region, __func__, \
++							  __LINE__)
++#define vmr_fput(region)		vmr_do_fput(region, __func__, __LINE__)
++#endif /* CONFIG_MMU */
++
+ extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
+ extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
+ 		void *buf, int len, int write);
+diff -Nur linux-4.0.4.orig/include/linux/mm_types.h linux-4.0.4/include/linux/mm_types.h
+--- linux-4.0.4.orig/include/linux/mm_types.h	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/include/linux/mm_types.h	2015-05-30 22:11:30.000000000 +0200
+@@ -241,6 +241,7 @@
+ 	unsigned long	vm_top;		/* region allocated to here */
+ 	unsigned long	vm_pgoff;	/* the offset in vm_file corresponding to vm_start */
+ 	struct file	*vm_file;	/* the backing file or NULL */
++	struct file	*vm_prfile;	/* the virtual backing file or NULL */
+ 
+ 	int		vm_usage;	/* region usage count (access under nommu_region_sem) */
+ 	bool		vm_icache_flushed : 1; /* true if the icache has been flushed for
+@@ -305,6 +306,7 @@
+ 	unsigned long vm_pgoff;		/* Offset (within vm_file) in PAGE_SIZE
+ 					   units, *not* PAGE_CACHE_SIZE */
+ 	struct file * vm_file;		/* File we map to (can be NULL). */
++	struct file *vm_prfile;		/* shadow of vm_file */
+ 	void * vm_private_data;		/* was vm_pte (shared mem) */
+ 
+ #ifndef CONFIG_MMU
+diff -Nur linux-4.0.4.orig/include/linux/splice.h linux-4.0.4/include/linux/splice.h
+--- linux-4.0.4.orig/include/linux/splice.h	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/include/linux/splice.h	2015-05-30 22:11:30.000000000 +0200
+@@ -83,4 +83,10 @@
+ extern void spd_release_page(struct splice_pipe_desc *, unsigned int);
+ 
+ extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
++
++extern long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
++			   loff_t *ppos, size_t len, unsigned int flags);
++extern long do_splice_to(struct file *in, loff_t *ppos,
++			 struct pipe_inode_info *pipe, size_t len,
++			 unsigned int flags);
+ #endif
+diff -Nur linux-4.0.4.orig/include/uapi/linux/aufs_type.h linux-4.0.4/include/uapi/linux/aufs_type.h
+--- linux-4.0.4.orig/include/uapi/linux/aufs_type.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/include/uapi/linux/aufs_type.h	2015-05-30 22:11:31.000000000 +0200
+@@ -0,0 +1,406 @@
++/*
++ * Copyright (C) 2005-2015 Junjiro R. Okajima
++ */
++
++#ifndef __AUFS_TYPE_H__
++#define __AUFS_TYPE_H__
++
++#define AUFS_NAME	"aufs"
++
++#ifdef __KERNEL__
++/*
++ * define it before including all other headers.
++ * sched.h may use pr_* macros before defining "current", so define the
++ * no-current version first, and re-define later.
++ */
++#define pr_fmt(fmt)	AUFS_NAME " %s:%d: " fmt, __func__, __LINE__
++#include <linux/sched.h>
++#undef pr_fmt
++#define pr_fmt(fmt) \
++		AUFS_NAME " %s:%d:%.*s[%d]: " fmt, __func__, __LINE__, \
++		(int)sizeof(current->comm), current->comm, current->pid
++#else
++#include <stdint.h>
++#include <sys/types.h>
++#endif /* __KERNEL__ */
++
++#include <linux/limits.h>
++
++#define AUFS_VERSION	"4.0"
++
++/* todo? move this to linux-2.6.19/include/magic.h */
++#define AUFS_SUPER_MAGIC	('a' << 24 | 'u' << 16 | 'f' << 8 | 's')
++
++/* ---------------------------------------------------------------------- */
++
++#ifdef CONFIG_AUFS_BRANCH_MAX_127
++typedef int8_t aufs_bindex_t;
++#define AUFS_BRANCH_MAX 127
++#else
++typedef int16_t aufs_bindex_t;
++#ifdef CONFIG_AUFS_BRANCH_MAX_511
++#define AUFS_BRANCH_MAX 511
++#elif defined(CONFIG_AUFS_BRANCH_MAX_1023)
++#define AUFS_BRANCH_MAX 1023
++#elif defined(CONFIG_AUFS_BRANCH_MAX_32767)
++#define AUFS_BRANCH_MAX 32767
++#endif
++#endif
++
++#ifdef __KERNEL__
++#ifndef AUFS_BRANCH_MAX
++#error unknown CONFIG_AUFS_BRANCH_MAX value
++#endif
++#endif /* __KERNEL__ */
++
++/* ---------------------------------------------------------------------- */
++
++#define AUFS_FSTYPE		AUFS_NAME
++
++#define AUFS_ROOT_INO		2
++#define AUFS_FIRST_INO		11
++
++#define AUFS_WH_PFX		".wh."
++#define AUFS_WH_PFX_LEN		((int)sizeof(AUFS_WH_PFX) - 1)
++#define AUFS_WH_TMP_LEN		4
++/* a limit for rmdir/rename a dir and copyup */
++#define AUFS_MAX_NAMELEN	(NAME_MAX \
++				- AUFS_WH_PFX_LEN * 2	/* doubly whiteouted */\
++				- 1			/* dot */\
++				- AUFS_WH_TMP_LEN)	/* hex */
++#define AUFS_XINO_FNAME		"." AUFS_NAME ".xino"
++#define AUFS_XINO_DEFPATH	"/tmp/" AUFS_XINO_FNAME
++#define AUFS_XINO_DEF_SEC	30 /* seconds */
++#define AUFS_XINO_DEF_TRUNC	45 /* percentage */
++#define AUFS_DIRWH_DEF		3
++#define AUFS_RDCACHE_DEF	10 /* seconds */
++#define AUFS_RDCACHE_MAX	3600 /* seconds */
++#define AUFS_RDBLK_DEF		512 /* bytes */
++#define AUFS_RDHASH_DEF		32
++#define AUFS_WKQ_NAME		AUFS_NAME "d"
++#define AUFS_MFS_DEF_SEC	30 /* seconds */
++#define AUFS_MFS_MAX_SEC	3600 /* seconds */
++#define AUFS_FHSM_CACHE_DEF_SEC	30 /* seconds */
++#define AUFS_PLINK_WARN		50 /* number of plinks in a single bucket */
++
++/* pseudo-link maintenace under /proc */
++#define AUFS_PLINK_MAINT_NAME	"plink_maint"
++#define AUFS_PLINK_MAINT_DIR	"fs/" AUFS_NAME
++#define AUFS_PLINK_MAINT_PATH	AUFS_PLINK_MAINT_DIR "/" AUFS_PLINK_MAINT_NAME
++
++#define AUFS_DIROPQ_NAME	AUFS_WH_PFX ".opq" /* whiteouted doubly */
++#define AUFS_WH_DIROPQ		AUFS_WH_PFX AUFS_DIROPQ_NAME
++
++#define AUFS_BASE_NAME		AUFS_WH_PFX AUFS_NAME
++#define AUFS_PLINKDIR_NAME	AUFS_WH_PFX "plnk"
++#define AUFS_ORPHDIR_NAME	AUFS_WH_PFX "orph"
++
++/* doubly whiteouted */
++#define AUFS_WH_BASE		AUFS_WH_PFX AUFS_BASE_NAME
++#define AUFS_WH_PLINKDIR	AUFS_WH_PFX AUFS_PLINKDIR_NAME
++#define AUFS_WH_ORPHDIR		AUFS_WH_PFX AUFS_ORPHDIR_NAME
++
++/* branch permissions and attributes */
++#define AUFS_BRPERM_RW		"rw"
++#define AUFS_BRPERM_RO		"ro"
++#define AUFS_BRPERM_RR		"rr"
++#define AUFS_BRATTR_COO_REG	"coo_reg"
++#define AUFS_BRATTR_COO_ALL	"coo_all"
++#define AUFS_BRATTR_FHSM	"fhsm"
++#define AUFS_BRATTR_UNPIN	"unpin"
++#define AUFS_BRATTR_ICEX	"icex"
++#define AUFS_BRATTR_ICEX_SEC	"icexsec"
++#define AUFS_BRATTR_ICEX_SYS	"icexsys"
++#define AUFS_BRATTR_ICEX_TR	"icextr"
++#define AUFS_BRATTR_ICEX_USR	"icexusr"
++#define AUFS_BRATTR_ICEX_OTH	"icexoth"
++#define AUFS_BRRATTR_WH		"wh"
++#define AUFS_BRWATTR_NLWH	"nolwh"
++#define AUFS_BRWATTR_MOO	"moo"
++
++#define AuBrPerm_RW		1		/* writable, hardlinkable wh */
++#define AuBrPerm_RO		(1 << 1)	/* readonly */
++#define AuBrPerm_RR		(1 << 2)	/* natively readonly */
++#define AuBrPerm_Mask		(AuBrPerm_RW | AuBrPerm_RO | AuBrPerm_RR)
++
++#define AuBrAttr_COO_REG	(1 << 3)	/* copy-up on open */
++#define AuBrAttr_COO_ALL	(1 << 4)
++#define AuBrAttr_COO_Mask	(AuBrAttr_COO_REG | AuBrAttr_COO_ALL)
++
++#define AuBrAttr_FHSM		(1 << 5)	/* file-based hsm */
++#define AuBrAttr_UNPIN		(1 << 6)	/* rename-able top dir of
++						   branch. meaningless since
++						   linux-3.18-rc1 */
++
++/* ignore error in copying XATTR */
++#define AuBrAttr_ICEX_SEC	(1 << 7)
++#define AuBrAttr_ICEX_SYS	(1 << 8)
++#define AuBrAttr_ICEX_TR	(1 << 9)
++#define AuBrAttr_ICEX_USR	(1 << 10)
++#define AuBrAttr_ICEX_OTH	(1 << 11)
++#define AuBrAttr_ICEX		(AuBrAttr_ICEX_SEC	\
++				 | AuBrAttr_ICEX_SYS	\
++				 | AuBrAttr_ICEX_TR	\
++				 | AuBrAttr_ICEX_USR	\
++				 | AuBrAttr_ICEX_OTH)
++
++#define AuBrRAttr_WH		(1 << 12)	/* whiteout-able */
++#define AuBrRAttr_Mask		AuBrRAttr_WH
++
++#define AuBrWAttr_NoLinkWH	(1 << 13)	/* un-hardlinkable whiteouts */
++#define AuBrWAttr_MOO		(1 << 14)	/* move-up on open */
++#define AuBrWAttr_Mask		(AuBrWAttr_NoLinkWH | AuBrWAttr_MOO)
++
++#define AuBrAttr_CMOO_Mask	(AuBrAttr_COO_Mask | AuBrWAttr_MOO)
++
++/* #warning test userspace */
++#ifdef __KERNEL__
++#ifndef CONFIG_AUFS_FHSM
++#undef AuBrAttr_FHSM
++#define AuBrAttr_FHSM		0
++#endif
++#ifndef CONFIG_AUFS_XATTR
++#undef	AuBrAttr_ICEX
++#define AuBrAttr_ICEX		0
++#undef	AuBrAttr_ICEX_SEC
++#define AuBrAttr_ICEX_SEC	0
++#undef	AuBrAttr_ICEX_SYS
++#define AuBrAttr_ICEX_SYS	0
++#undef	AuBrAttr_ICEX_TR
++#define AuBrAttr_ICEX_TR	0
++#undef	AuBrAttr_ICEX_USR
++#define AuBrAttr_ICEX_USR	0
++#undef	AuBrAttr_ICEX_OTH
++#define AuBrAttr_ICEX_OTH	0
++#endif
++#endif
++
++/* the longest combination */
++/* AUFS_BRATTR_ICEX and AUFS_BRATTR_ICEX_TR don't affect here */
++#define AuBrPermStrSz	sizeof(AUFS_BRPERM_RW			\
++			       "+" AUFS_BRATTR_COO_REG		\
++			       "+" AUFS_BRATTR_FHSM		\
++			       "+" AUFS_BRATTR_UNPIN		\
++			       "+" AUFS_BRATTR_ICEX_SEC		\
++			       "+" AUFS_BRATTR_ICEX_SYS		\
++			       "+" AUFS_BRATTR_ICEX_USR		\
++			       "+" AUFS_BRATTR_ICEX_OTH		\
++			       "+" AUFS_BRWATTR_NLWH)
++
++typedef struct {
++	char a[AuBrPermStrSz];
++} au_br_perm_str_t;
++
++static inline int au_br_writable(int brperm)
++{
++	return brperm & AuBrPerm_RW;
++}
++
++static inline int au_br_whable(int brperm)
++{
++	return brperm & (AuBrPerm_RW | AuBrRAttr_WH);
++}
++
++static inline int au_br_wh_linkable(int brperm)
++{
++	return !(brperm & AuBrWAttr_NoLinkWH);
++}
++
++static inline int au_br_cmoo(int brperm)
++{
++	return brperm & AuBrAttr_CMOO_Mask;
++}
++
++static inline int au_br_fhsm(int brperm)
++{
++	return brperm & AuBrAttr_FHSM;
++}
++
++/* ---------------------------------------------------------------------- */
++
++/* ioctl */
++enum {
++	/* readdir in userspace */
++	AuCtl_RDU,
++	AuCtl_RDU_INO,
++
++	AuCtl_WBR_FD,	/* pathconf wrapper */
++	AuCtl_IBUSY,	/* busy inode */
++	AuCtl_MVDOWN,	/* move-down */
++	AuCtl_BR,	/* info about branches */
++	AuCtl_FHSM_FD	/* connection for fhsm */
++};
++
++/* borrowed from linux/include/linux/kernel.h */
++#ifndef ALIGN
++#define ALIGN(x, a)		__ALIGN_MASK(x, (typeof(x))(a)-1)
++#define __ALIGN_MASK(x, mask)	(((x)+(mask))&~(mask))
++#endif
++
++/* borrowed from linux/include/linux/compiler-gcc3.h */
++#ifndef __aligned
++#define __aligned(x)			__attribute__((aligned(x)))
++#endif
++
++#ifdef __KERNEL__
++#ifndef __packed
++#define __packed			__attribute__((packed))
++#endif
++#endif
++
++struct au_rdu_cookie {
++	uint64_t	h_pos;
++	int16_t		bindex;
++	uint8_t		flags;
++	uint8_t		pad;
++	uint32_t	generation;
++} __aligned(8);
++
++struct au_rdu_ent {
++	uint64_t	ino;
++	int16_t		bindex;
++	uint8_t		type;
++	uint8_t		nlen;
++	uint8_t		wh;
++	char		name[0];
++} __aligned(8);
++
++static inline int au_rdu_len(int nlen)
++{
++	/* include the terminating NULL */
++	return ALIGN(sizeof(struct au_rdu_ent) + nlen + 1,
++		     sizeof(uint64_t));
++}
++
++union au_rdu_ent_ul {
++	struct au_rdu_ent __user	*e;
++	uint64_t			ul;
++};
++
++enum {
++	AufsCtlRduV_SZ,
++	AufsCtlRduV_End
++};
++
++struct aufs_rdu {
++	/* input */
++	union {
++		uint64_t	sz;	/* AuCtl_RDU */
++		uint64_t	nent;	/* AuCtl_RDU_INO */
++	};
++	union au_rdu_ent_ul	ent;
++	uint16_t		verify[AufsCtlRduV_End];
++
++	/* input/output */
++	uint32_t		blk;
++
++	/* output */
++	union au_rdu_ent_ul	tail;
++	/* number of entries which were added in a single call */
++	uint64_t		rent;
++	uint8_t			full;
++	uint8_t			shwh;
++
++	struct au_rdu_cookie	cookie;
++} __aligned(8);
++
++/* ---------------------------------------------------------------------- */
++
++struct aufs_wbr_fd {
++	uint32_t	oflags;
++	int16_t		brid;
++} __aligned(8);
++
++/* ---------------------------------------------------------------------- */
++
++struct aufs_ibusy {
++	uint64_t	ino, h_ino;
++	int16_t		bindex;
++} __aligned(8);
++
++/* ---------------------------------------------------------------------- */
++
++/* error code for move-down */
++/* the actual message strings are implemented in aufs-util.git */
++enum {
++	EAU_MVDOWN_OPAQUE = 1,
++	EAU_MVDOWN_WHITEOUT,
++	EAU_MVDOWN_UPPER,
++	EAU_MVDOWN_BOTTOM,
++	EAU_MVDOWN_NOUPPER,
++	EAU_MVDOWN_NOLOWERBR,
++	EAU_Last
++};
++
++/* flags for move-down */
++#define AUFS_MVDOWN_DMSG	1
++#define AUFS_MVDOWN_OWLOWER	(1 << 1)	/* overwrite lower */
++#define AUFS_MVDOWN_KUPPER	(1 << 2)	/* keep upper */
++#define AUFS_MVDOWN_ROLOWER	(1 << 3)	/* do even if lower is RO */
++#define AUFS_MVDOWN_ROLOWER_R	(1 << 4)	/* did on lower RO */
++#define AUFS_MVDOWN_ROUPPER	(1 << 5)	/* do even if upper is RO */
++#define AUFS_MVDOWN_ROUPPER_R	(1 << 6)	/* did on upper RO */
++#define AUFS_MVDOWN_BRID_UPPER	(1 << 7)	/* upper brid */
++#define AUFS_MVDOWN_BRID_LOWER	(1 << 8)	/* lower brid */
++#define AUFS_MVDOWN_FHSM_LOWER	(1 << 9)	/* find fhsm attr for lower */
++#define AUFS_MVDOWN_STFS	(1 << 10)	/* req. stfs */
++#define AUFS_MVDOWN_STFS_FAILED	(1 << 11)	/* output: stfs is unusable */
++#define AUFS_MVDOWN_BOTTOM	(1 << 12)	/* output: no more lowers */
++
++/* index for move-down */
++enum {
++	AUFS_MVDOWN_UPPER,
++	AUFS_MVDOWN_LOWER,
++	AUFS_MVDOWN_NARRAY
++};
++
++/*
++ * additional info of move-down
++ * number of free blocks and inodes.
++ * subset of struct kstatfs, but smaller and always 64bit.
++ */
++struct aufs_stfs {
++	uint64_t	f_blocks;
++	uint64_t	f_bavail;
++	uint64_t	f_files;
++	uint64_t	f_ffree;
++};
++
++struct aufs_stbr {
++	int16_t			brid;	/* optional input */
++	int16_t			bindex;	/* output */
++	struct aufs_stfs	stfs;	/* output when AUFS_MVDOWN_STFS set */
++} __aligned(8);
++
++struct aufs_mvdown {
++	uint32_t		flags;			/* input/output */
++	struct aufs_stbr	stbr[AUFS_MVDOWN_NARRAY]; /* input/output */
++	int8_t			au_errno;		/* output */
++} __aligned(8);
++
++/* ---------------------------------------------------------------------- */
++
++union aufs_brinfo {
++	/* PATH_MAX may differ between kernel-space and user-space */
++	char	_spacer[4096];
++	struct {
++		int16_t	id;
++		int	perm;
++		char	path[0];
++	};
++} __aligned(8);
++
++/* ---------------------------------------------------------------------- */
++
++#define AuCtlType		'A'
++#define AUFS_CTL_RDU		_IOWR(AuCtlType, AuCtl_RDU, struct aufs_rdu)
++#define AUFS_CTL_RDU_INO	_IOWR(AuCtlType, AuCtl_RDU_INO, struct aufs_rdu)
++#define AUFS_CTL_WBR_FD		_IOW(AuCtlType, AuCtl_WBR_FD, \
++				     struct aufs_wbr_fd)
++#define AUFS_CTL_IBUSY		_IOWR(AuCtlType, AuCtl_IBUSY, struct aufs_ibusy)
++#define AUFS_CTL_MVDOWN		_IOWR(AuCtlType, AuCtl_MVDOWN, \
++				      struct aufs_mvdown)
++#define AUFS_CTL_BRINFO		_IOW(AuCtlType, AuCtl_BR, union aufs_brinfo)
++#define AUFS_CTL_FHSM_FD	_IOW(AuCtlType, AuCtl_FHSM_FD, int)
++
++#endif /* __AUFS_TYPE_H__ */
+diff -Nur linux-4.0.4.orig/include/uapi/linux/Kbuild linux-4.0.4/include/uapi/linux/Kbuild
+--- linux-4.0.4.orig/include/uapi/linux/Kbuild	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/include/uapi/linux/Kbuild	2015-05-30 22:11:31.000000000 +0200
+@@ -58,6 +58,7 @@
+ header-y += atm_tcp.h
+ header-y += atm_zatm.h
+ header-y += audit.h
++header-y += aufs_type.h
+ header-y += auto_fs4.h
+ header-y += auto_fs.h
+ header-y += auxvec.h
+diff -Nur linux-4.0.4.orig/kernel/fork.c linux-4.0.4/kernel/fork.c
+--- linux-4.0.4.orig/kernel/fork.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/kernel/fork.c	2015-05-30 22:11:30.000000000 +0200
+@@ -430,7 +430,7 @@
+ 			struct inode *inode = file_inode(file);
+ 			struct address_space *mapping = file->f_mapping;
+ 
+-			get_file(file);
++			vma_get_file(tmp);
+ 			if (tmp->vm_flags & VM_DENYWRITE)
+ 				atomic_dec(&inode->i_writecount);
+ 			i_mmap_lock_write(mapping);
+diff -Nur linux-4.0.4.orig/MAINTAINERS linux-4.0.4/MAINTAINERS
+--- linux-4.0.4.orig/MAINTAINERS	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/MAINTAINERS	2015-05-30 22:11:31.000000000 +0200
+@@ -1864,6 +1864,19 @@
+ F:	include/uapi/linux/audit.h
+ F:	kernel/audit*
+ 
++AUFS (advanced multi layered unification filesystem) FILESYSTEM
++M:	"J. R. Okajima" <hooanon05g@gmail.com>
++L:	linux-unionfs@vger.kernel.org
++L:	aufs-users@lists.sourceforge.net (members only)
++W:	http://aufs.sourceforge.net
++T:	git://github.com/sfjro/aufs4-linux.git
++S:	Supported
++F:	Documentation/filesystems/aufs/
++F:	Documentation/ABI/testing/debugfs-aufs
++F:	Documentation/ABI/testing/sysfs-aufs
++F:	fs/aufs/
++F:	include/uapi/linux/aufs_type.h
++
+ AUXILIARY DISPLAY DRIVERS
+ M:	Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
+ W:	http://miguelojeda.es/auxdisplay.htm
+diff -Nur linux-4.0.4.orig/mm/filemap.c linux-4.0.4/mm/filemap.c
+--- linux-4.0.4.orig/mm/filemap.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/mm/filemap.c	2015-05-30 22:11:30.000000000 +0200
+@@ -2064,7 +2064,7 @@
+ 	int ret = VM_FAULT_LOCKED;
+ 
+ 	sb_start_pagefault(inode->i_sb);
+-	file_update_time(vma->vm_file);
++	vma_file_update_time(vma);
+ 	lock_page(page);
+ 	if (page->mapping != inode->i_mapping) {
+ 		unlock_page(page);
+diff -Nur linux-4.0.4.orig/mm/madvise.c linux-4.0.4/mm/madvise.c
+--- linux-4.0.4.orig/mm/madvise.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/mm/madvise.c	2015-05-30 22:11:30.000000000 +0200
+@@ -320,12 +320,12 @@
+ 	 * vma's reference to the file) can go away as soon as we drop
+ 	 * mmap_sem.
+ 	 */
+-	get_file(f);
++	vma_get_file(vma);
+ 	up_read(&current->mm->mmap_sem);
+ 	error = vfs_fallocate(f,
+ 				FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ 				offset, end - start);
+-	fput(f);
++	vma_fput(vma);
+ 	down_read(&current->mm->mmap_sem);
+ 	return error;
+ }
+diff -Nur linux-4.0.4.orig/mm/Makefile linux-4.0.4/mm/Makefile
+--- linux-4.0.4.orig/mm/Makefile	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/mm/Makefile	2015-05-30 22:11:30.000000000 +0200
+@@ -21,7 +21,7 @@
+ 			   mm_init.o mmu_context.o percpu.o slab_common.o \
+ 			   compaction.o vmacache.o \
+ 			   interval_tree.o list_lru.o workingset.o \
+-			   debug.o $(mmu-y)
++			   prfile.o debug.o $(mmu-y)
+ 
+ obj-y += init-mm.o
+ 
+diff -Nur linux-4.0.4.orig/mm/memory.c linux-4.0.4/mm/memory.c
+--- linux-4.0.4.orig/mm/memory.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/mm/memory.c	2015-05-30 22:11:30.000000000 +0200
+@@ -2132,7 +2132,7 @@
+ 			}
+ 
+ 			if (!page_mkwrite)
+-				file_update_time(vma->vm_file);
++				vma_file_update_time(vma);
+ 		}
+ 
+ 		return ret;
+diff -Nur linux-4.0.4.orig/mm/mmap.c linux-4.0.4/mm/mmap.c
+--- linux-4.0.4.orig/mm/mmap.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/mm/mmap.c	2015-05-30 22:11:30.000000000 +0200
+@@ -274,7 +274,7 @@
+ 	if (vma->vm_ops && vma->vm_ops->close)
+ 		vma->vm_ops->close(vma);
+ 	if (vma->vm_file)
+-		fput(vma->vm_file);
++		vma_fput(vma);
+ 	mpol_put(vma_policy(vma));
+ 	kmem_cache_free(vm_area_cachep, vma);
+ 	return next;
+@@ -886,7 +886,7 @@
+ 	if (remove_next) {
+ 		if (file) {
+ 			uprobe_munmap(next, next->vm_start, next->vm_end);
+-			fput(file);
++			vma_fput(vma);
+ 		}
+ 		if (next->anon_vma)
+ 			anon_vma_merge(vma, next);
+@@ -1671,8 +1671,8 @@
+ 	return addr;
+ 
+ unmap_and_free_vma:
++	vma_fput(vma);
+ 	vma->vm_file = NULL;
+-	fput(file);
+ 
+ 	/* Undo any partial mapping done by a device driver. */
+ 	unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
+@@ -2473,7 +2473,7 @@
+ 		goto out_free_mpol;
+ 
+ 	if (new->vm_file)
+-		get_file(new->vm_file);
++		vma_get_file(new);
+ 
+ 	if (new->vm_ops && new->vm_ops->open)
+ 		new->vm_ops->open(new);
+@@ -2492,7 +2492,7 @@
+ 	if (new->vm_ops && new->vm_ops->close)
+ 		new->vm_ops->close(new);
+ 	if (new->vm_file)
+-		fput(new->vm_file);
++		vma_fput(new);
+ 	unlink_anon_vmas(new);
+  out_free_mpol:
+ 	mpol_put(vma_policy(new));
+@@ -2635,7 +2635,6 @@
+ 	struct vm_area_struct *vma;
+ 	unsigned long populate = 0;
+ 	unsigned long ret = -EINVAL;
+-	struct file *file;
+ 
+ 	pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. "
+ 			"See Documentation/vm/remap_file_pages.txt.\n",
+@@ -2679,10 +2678,10 @@
+ 		munlock_vma_pages_range(vma, start, start + size);
+ 	}
+ 
+-	file = get_file(vma->vm_file);
++	vma_get_file(vma);
+ 	ret = do_mmap_pgoff(vma->vm_file, start, size,
+ 			prot, flags, pgoff, &populate);
+-	fput(file);
++	vma_fput(vma);
+ out:
+ 	up_write(&mm->mmap_sem);
+ 	if (populate)
+@@ -2950,7 +2949,7 @@
+ 			if (anon_vma_clone(new_vma, vma))
+ 				goto out_free_mempol;
+ 			if (new_vma->vm_file)
+-				get_file(new_vma->vm_file);
++				vma_get_file(new_vma);
+ 			if (new_vma->vm_ops && new_vma->vm_ops->open)
+ 				new_vma->vm_ops->open(new_vma);
+ 			vma_link(mm, new_vma, prev, rb_link, rb_parent);
+diff -Nur linux-4.0.4.orig/mm/msync.c linux-4.0.4/mm/msync.c
+--- linux-4.0.4.orig/mm/msync.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/mm/msync.c	2015-05-30 22:11:30.000000000 +0200
+@@ -84,10 +84,10 @@
+ 		start = vma->vm_end;
+ 		if ((flags & MS_SYNC) && file &&
+ 				(vma->vm_flags & VM_SHARED)) {
+-			get_file(file);
++			vma_get_file(vma);
+ 			up_read(&mm->mmap_sem);
+ 			error = vfs_fsync_range(file, fstart, fend, 1);
+-			fput(file);
++			vma_fput(vma);
+ 			if (error || start >= end)
+ 				goto out;
+ 			down_read(&mm->mmap_sem);
+diff -Nur linux-4.0.4.orig/mm/nommu.c linux-4.0.4/mm/nommu.c
+--- linux-4.0.4.orig/mm/nommu.c	2015-05-17 18:55:21.000000000 +0200
++++ linux-4.0.4/mm/nommu.c	2015-05-30 22:11:30.000000000 +0200
+@@ -693,7 +693,7 @@
+ 		up_write(&nommu_region_sem);
+ 
+ 		if (region->vm_file)
+-			fput(region->vm_file);
++			vmr_fput(region);
+ 
+ 		/* IO memory and memory shared directly out of the pagecache
+ 		 * from ramfs/tmpfs mustn't be released here */
+@@ -858,7 +858,7 @@
+ 	if (vma->vm_ops && vma->vm_ops->close)
+ 		vma->vm_ops->close(vma);
+ 	if (vma->vm_file)
+-		fput(vma->vm_file);
++		vma_fput(vma);
+ 	put_nommu_region(vma->vm_region);
+ 	kmem_cache_free(vm_area_cachep, vma);
+ }
+@@ -1398,7 +1398,7 @@
+ 					goto error_just_free;
+ 				}
+ 			}
+-			fput(region->vm_file);
++			vmr_fput(region);
+ 			kmem_cache_free(vm_region_jar, region);
+ 			region = pregion;
+ 			result = start;
+@@ -1474,10 +1474,10 @@
+ 	up_write(&nommu_region_sem);
+ error:
+ 	if (region->vm_file)
+-		fput(region->vm_file);
++		vmr_fput(region);
+ 	kmem_cache_free(vm_region_jar, region);
+ 	if (vma->vm_file)
+-		fput(vma->vm_file);
++		vma_fput(vma);
+ 	kmem_cache_free(vm_area_cachep, vma);
+ 	kleave(" = %d", ret);
+ 	return ret;
+diff -Nur linux-4.0.4.orig/mm/prfile.c linux-4.0.4/mm/prfile.c
+--- linux-4.0.4.orig/mm/prfile.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.0.4/mm/prfile.c	2015-05-30 22:11:30.000000000 +0200
+@@ -0,0 +1,86 @@
++/*
++ * Mainly for aufs which mmap(2) diffrent file and wants to print different path
++ * in /proc/PID/maps.
++ * Call these functions via macros defined in linux/mm.h.
++ *
++ * See Documentation/filesystems/aufs/design/06mmap.txt
++ *
++ * Copyright (c) 2014 Junjro R. Okajima
++ * Copyright (c) 2014 Ian Campbell
++ */
++
++#include <linux/mm.h>
++#include <linux/file.h>
++#include <linux/fs.h>
++
++/* #define PRFILE_TRACE */
++static inline void prfile_trace(struct file *f, struct file *pr,
++			      const char func[], int line, const char func2[])
++{
++#ifdef PRFILE_TRACE
++	if (pr)
++		pr_info("%s:%d: %s, %p\n", func, line, func2,
++			f ? (char *)f->f_path.dentry->d_name.name : "(null)");
++#endif
++}
++
++#ifdef CONFIG_MMU
++void vma_do_file_update_time(struct vm_area_struct *vma, const char func[],
++			     int line)
++{
++	struct file *f = vma->vm_file, *pr = vma->vm_prfile;
++
++	prfile_trace(f, pr, func, line, __func__);
++	file_update_time(f);
++	if (f && pr)
++		file_update_time(pr);
++}
++
++struct file *vma_do_pr_or_file(struct vm_area_struct *vma, const char func[],
++			       int line)
++{
++	struct file *f = vma->vm_file, *pr = vma->vm_prfile;
++
++	prfile_trace(f, pr, func, line, __func__);
++	return (f && pr) ? pr : f;
++}
++
++void vma_do_get_file(struct vm_area_struct *vma, const char func[], int line)
++{
++	struct file *f = vma->vm_file, *pr = vma->vm_prfile;
++
++	prfile_trace(f, pr, func, line, __func__);
++	get_file(f);
++	if (f && pr)
++		get_file(pr);
++}
++
++void vma_do_fput(struct vm_area_struct *vma, const char func[], int line)
++{
++	struct file *f = vma->vm_file, *pr = vma->vm_prfile;
++
++	prfile_trace(f, pr, func, line, __func__);
++	fput(f);
++	if (f && pr)
++		fput(pr);
++}
++#else
++struct file *vmr_do_pr_or_file(struct vm_region *region, const char func[],
++			       int line)
++{
++	struct file *f = region->vm_file, *pr = region->vm_prfile;
++
++	prfile_trace(f, pr, func, line, __func__);
++	return (f && pr) ? pr : f;
++}
++
++void vmr_do_fput(struct vm_region *region, const char func[], int line)
++{
++	struct file *f = region->vm_file, *pr = region->vm_prfile;
++
++	prfile_trace(f, pr, func, line, __func__);
++	fput(f);
++	if (f && pr)
++		fput(pr);
++}
++#endif /* CONFIG_MMU */
diff --git a/target/linux/patches/4.0.4/cleankernel.patch b/target/linux/patches/4.0.4/cleankernel.patch
new file mode 100644
index 000000000..d8c055dc3
--- /dev/null
+++ b/target/linux/patches/4.0.4/cleankernel.patch
@@ -0,0 +1,11 @@
+diff -Nur linux-3.11.5.orig/scripts/Makefile.headersinst linux-3.11.5/scripts/Makefile.headersinst
+--- linux-3.11.5.orig/scripts/Makefile.headersinst	2013-10-14 03:14:45.000000000 +0200
++++ linux-3.11.5/scripts/Makefile.headersinst	2013-10-15 16:33:10.000000000 +0200
+@@ -107,7 +107,6 @@
+ 
+ targets += $(install-file)
+ $(install-file): scripts/headers_install.sh $(input-files1) $(input-files2) $(input-files3) FORCE
+-	$(if $(unwanted),$(call cmd,remove),)
+ 	$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
+ 	$(call if_changed,install)
+