linux-moblin2: Use a more generic name

And fix the eee901 machine file accordingly.


git-svn-id: https://svn.o-hand.com/repos/poky/trunk@5404 311d38ba-8fff-0310-9ca6-ca027cbcb966

1 files changed, 0 insertions, 11320 deletions

diff --git a/meta/packages/linux/linux-moblin2-2.6.27-rc1/0010_unionfs-2.4_for_2.6.27-rc1.patch b/meta/packages/linux/linux-moblin2-2.6.27-rc1/0010_unionfs-2.4_for_2.6.27-rc1.patch
deleted file mode 100644
index 8a2e83aa6..000000000
--- a/meta/packages/linux/linux-moblin2-2.6.27-rc1/0010_unionfs-2.4_for_2.6.27-rc1.patch
+++ /dev/null
@@ -1,11320 +0,0 @@
-diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
-index 52cd611..bc6b437 100644
---- a/Documentation/filesystems/00-INDEX
-+++ b/Documentation/filesystems/00-INDEX
-@@ -106,6 +106,8 @@ udf.txt
- 	- info and mount options for the UDF filesystem.
- ufs.txt
- 	- info on the ufs filesystem.
-+unionfs/
-+	- info on the unionfs filesystem
- vfat.txt
- 	- info on using the VFAT filesystem used in Windows NT and Windows 95
- vfs.txt
-diff --git a/Documentation/filesystems/unionfs/00-INDEX b/Documentation/filesystems/unionfs/00-INDEX
-new file mode 100644
-index 0000000..96fdf67
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/00-INDEX
-@@ -0,0 +1,10 @@
-+00-INDEX
-+	- this file.
-+concepts.txt
-+	- A brief introduction of concepts.
-+issues.txt
-+	- A summary of known issues with unionfs.
-+rename.txt
-+	- Information regarding rename operations.
-+usage.txt
-+	- Usage information and examples.
-diff --git a/Documentation/filesystems/unionfs/concepts.txt b/Documentation/filesystems/unionfs/concepts.txt
-new file mode 100644
-index 0000000..b853788
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/concepts.txt
-@@ -0,0 +1,287 @@
-+Unionfs 2.x CONCEPTS:
-+=====================
-+
-+This file describes the concepts needed by a namespace unification file
-+system.
-+
-+
-+Branch Priority:
-+================
-+
-+Each branch is assigned a unique priority - starting from 0 (highest
-+priority).  No two branches can have the same priority.
-+
-+
-+Branch Mode:
-+============
-+
-+Each branch is assigned a mode - read-write or read-only. This allows
-+directories on media mounted read-write to be used in a read-only manner.
-+
-+
-+Whiteouts:
-+==========
-+
-+A whiteout removes a file name from the namespace. Whiteouts are needed when
-+one attempts to remove a file on a read-only branch.
-+
-+Suppose we have a two-branch union, where branch 0 is read-write and branch
-+1 is read-only. And a file 'foo' on branch 1:
-+
-+./b0/
-+./b1/
-+./b1/foo
-+
-+The unified view would simply be:
-+
-+./union/
-+./union/foo
-+
-+Since 'foo' is stored on a read-only branch, it cannot be removed. A
-+whiteout is used to remove the name 'foo' from the unified namespace. Again,
-+since branch 1 is read-only, the whiteout cannot be created there. So, we
-+try on a higher priority (lower numerically) branch and create the whiteout
-+there.
-+
-+./b0/
-+./b0/.wh.foo
-+./b1/
-+./b1/foo
-+
-+Later, when Unionfs traverses branches (due to lookup or readdir), it
-+eliminate 'foo' from the namespace (as well as the whiteout itself.)
-+
-+
-+Opaque Directories:
-+===================
-+
-+Assume we have a unionfs mount comprising of two branches.  Branch 0 is
-+empty; branch 1 has the directory /a and file /a/f.  Let's say we mount a
-+union of branch 0 as read-write and branch 1 as read-only.  Now, let's say
-+we try to perform the following operation in the union:
-+
-+	rm -fr a
-+
-+Because branch 1 is not writable, we cannot physically remove the file /a/f
-+or the directory /a.  So instead, we will create a whiteout in branch 0
-+named /.wh.a, masking out the name "a" from branch 1.  Next, let's say we
-+try to create a directory named "a" as follows:
-+
-+	mkdir a
-+
-+Because we have a whiteout for "a" already, Unionfs behaves as if "a"
-+doesn't exist, and thus will delete the whiteout and replace it with an
-+actual directory named "a".
-+
-+The problem now is that if you try to "ls" in the union, Unionfs will
-+perform is normal directory name unification, for *all* directories named
-+"a" in all branches.  This will cause the file /a/f from branch 1 to
-+re-appear in the union's namespace, which violates Unix semantics.
-+
-+To avoid this problem, we have a different form of whiteouts for
-+directories, called "opaque directories" (same as BSD Union Mount does).
-+Whenever we replace a whiteout with a directory, that directory is marked as
-+opaque.  In Unionfs 2.x, it means that we create a file named
-+/a/.wh.__dir_opaque in branch 0, after having created directory /a there.
-+When unionfs notices that a directory is opaque, it stops all namespace
-+operations (including merging readdir contents) at that opaque directory.
-+This prevents re-exposing names from masked out directories.
-+
-+
-+Duplicate Elimination:
-+======================
-+
-+It is possible for files on different branches to have the same name.
-+Unionfs then has to select which instance of the file to show to the user.
-+Given the fact that each branch has a priority associated with it, the
-+simplest solution is to take the instance from the highest priority
-+(numerically lowest value) and "hide" the others.
-+
-+
-+Unlinking:
-+=========
-+
-+Unlink operation on non-directory instances is optimized to remove the
-+maximum possible objects in case multiple underlying branches have the same
-+file name.  The unlink operation will first try to delete file instances
-+from highest priority branch and then move further to delete from remaining
-+branches in order of their decreasing priority.  Consider a case (F..D..F),
-+where F is a file and D is a directory of the same name; here, some
-+intermediate branch could have an empty directory instance with the same
-+name, so this operation also tries to delete this directory instance and
-+proceed further to delete from next possible lower priority branch.  The
-+unionfs unlink operation will smoothly delete the files with same name from
-+all possible underlying branches.  In case if some error occurs, it creates
-+whiteout in highest priority branch that will hide file instance in rest of
-+the branches.  An error could occur either if an unlink operations in any of
-+the underlying branch failed or if a branch has no write permission.
-+
-+This unlinking policy is known as "delete all" and it has the benefit of
-+overall reducing the number of inodes used by duplicate files, and further
-+reducing the total number of inodes consumed by whiteouts.  The cost is of
-+extra processing, but testing shows this extra processing is well worth the
-+savings.
-+
-+
-+Copyup:
-+=======
-+
-+When a change is made to the contents of a file's data or meta-data, they
-+have to be stored somewhere.  The best way is to create a copy of the
-+original file on a branch that is writable, and then redirect the write
-+though to this copy.  The copy must be made on a higher priority branch so
-+that lookup and readdir return this newer "version" of the file rather than
-+the original (see duplicate elimination).
-+
-+An entire unionfs mount can be read-only or read-write.  If it's read-only,
-+then none of the branches will be written to, even if some of the branches
-+are physically writeable.  If the unionfs mount is read-write, then the
-+leftmost (highest priority) branch must be writeable (for copyup to take
-+place); the remaining branches can be any mix of read-write and read-only.
-+
-+In a writeable mount, unionfs will create new files/dir in the leftmost
-+branch.  If one tries to modify a file in a read-only branch/media, unionfs
-+will copyup the file to the leftmost branch and modify it there.  If you try
-+to modify a file from a writeable branch which is not the leftmost branch,
-+then unionfs will modify it in that branch; this is useful if you, say,
-+unify differnet packages (e.g., apache, sendmail, ftpd, etc.) and you want
-+changes to specific package files to remain logically in the directory where
-+they came from.
-+
-+Cache Coherency:
-+================
-+
-+Unionfs users often want to be able to modify files and directories directly
-+on the lower branches, and have those changes be visible at the Unionfs
-+level.  This means that data (e.g., pages) and meta-data (dentries, inodes,
-+open files, etc.) have to be synchronized between the upper and lower
-+layers.  In other words, the newest changes from a layer below have to be
-+propagated to the Unionfs layer above.  If the two layers are not in sync, a
-+cache incoherency ensues, which could lead to application failures and even
-+oopses.  The Linux kernel, however, has a rather limited set of mechanisms
-+to ensure this inter-layer cache coherency---so Unionfs has to do most of
-+the hard work on its own.
-+
-+Maintaining Invariants:
-+
-+The way Unionfs ensures cache coherency is as follows.  At each entry point
-+to a Unionfs file system method, we call a utility function to validate the
-+primary objects of this method.  Generally, we call unionfs_file_revalidate
-+on open files, and __unionfs_d_revalidate_chain on dentries (which also
-+validates inodes).  These utility functions check to see whether the upper
-+Unionfs object is in sync with any of the lower objects that it represents.
-+The checks we perform include whether the Unionfs superblock has a newer
-+generation number, or if any of the lower objects mtime's or ctime's are
-+newer.  (Note: generation numbers change when branch-management commands are
-+issued, so in a way, maintaining cache coherency is also very important for
-+branch-management.)  If indeed we determine that any Unionfs object is no
-+longer in sync with its lower counterparts, then we rebuild that object
-+similarly to how we do so for branch-management.
-+
-+While rebuilding Unionfs's objects, we also purge any page mappings and
-+truncate inode pages (see fs/unionfs/dentry.c:purge_inode_data).  This is to
-+ensure that Unionfs will re-get the newer data from the lower branches.  We
-+perform this purging only if the Unionfs operation in question is a reading
-+operation; if Unionfs is performing a data writing operation (e.g., ->write,
-+->commit_write, etc.) then we do NOT flush the lower mappings/pages: this is
-+because (1) a self-deadlock could occur and (2) the upper Unionfs pages are
-+considered more authoritative anyway, as they are newer and will overwrite
-+any lower pages.
-+
-+Unionfs maintains the following important invariant regarding mtime's,
-+ctime's, and atime's: the upper inode object's times are the max() of all of
-+the lower ones.  For non-directory objects, there's only one object below,
-+so the mapping is simple; for directory objects, there could me multiple
-+lower objects and we have to sync up with the newest one of all the lower
-+ones.  This invariant is important to maintain, especially for directories
-+(besides, we need this to be POSIX compliant).  A union could comprise
-+multiple writable branches, each of which could change.  If we don't reflect
-+the newest possible mtime/ctime, some applications could fail.  For example,
-+NFSv2/v3 exports check for newer directory mtimes on the server to determine
-+if the client-side attribute cache should be purged.
-+
-+To maintain these important invariants, of course, Unionfs carefully
-+synchronizes upper and lower times in various places.  For example, if we
-+copy-up a file to a top-level branch, the parent directory where the file
-+was copied up to will now have a new mtime: so after a successful copy-up,
-+we sync up with the new top-level branch's parent directory mtime.
-+
-+Implementation:
-+
-+This cache-coherency implementation is efficient because it defers any
-+synchronizing between the upper and lower layers until absolutely needed.
-+Consider the example a common situation where users perform a lot of lower
-+changes, such as untarring a whole package.  While these take place,
-+typically the user doesn't access the files via Unionfs; only after the
-+lower changes are done, does the user try to access the lower files.  With
-+our cache-coherency implementation, the entirety of the changes to the lower
-+branches will not result in a single CPU cycle spent at the Unionfs level
-+until the user invokes a system call that goes through Unionfs.
-+
-+We have considered two alternate cache-coherency designs.  (1) Using the
-+dentry/inode notify functionality to register interest in finding out about
-+any lower changes.  This is a somewhat limited and also a heavy-handed
-+approach which could result in many notifications to the Unionfs layer upon
-+each small change at the lower layer (imagine a file being modified multiple
-+times in rapid succession).  (2) Rewriting the VFS to support explicit
-+callbacks from lower objects to upper objects.  We began exploring such an
-+implementation, but found it to be very complicated--it would have resulted
-+in massive VFS/MM changes which are unlikely to be accepted by the LKML
-+community.  We therefore believe that our current cache-coherency design and
-+implementation represent the best approach at this time.
-+
-+Limitations:
-+
-+Our implementation works in that as long as a user process will have caused
-+Unionfs to be called, directly or indirectly, even to just do
-+->d_revalidate; then we will have purged the current Unionfs data and the
-+process will see the new data.  For example, a process that continually
-+re-reads the same file's data will see the NEW data as soon as the lower
-+file had changed, upon the next read(2) syscall (even if the file is still
-+open!)  However, this doesn't work when the process re-reads the open file's
-+data via mmap(2) (unless the user unmaps/closes the file and remaps/reopens
-+it).  Once we respond to ->readpage(s), then the kernel maps the page into
-+the process's address space and there doesn't appear to be a way to force
-+the kernel to invalidate those pages/mappings, and force the process to
-+re-issue ->readpage.  If there's a way to invalidate active mappings and
-+force a ->readpage, let us know please (invalidate_inode_pages2 doesn't do
-+the trick).
-+
-+Our current Unionfs code has to perform many file-revalidation calls.  It
-+would be really nice if the VFS would export an optional file system hook
-+->file_revalidate (similarly to dentry->d_revalidate) that will be called
-+before each VFS op that has a "struct file" in it.
-+
-+Certain file systems have micro-second granularity (or better) for inode
-+times, and asynchronous actions could cause those times to change with some
-+small delay.  In such cases, Unionfs may see a changed inode time that only
-+differs by a tiny fraction of a second: such a change may be a false
-+positive indication that the lower object has changed, whereas if unionfs
-+waits a little longer, that false indication will not be seen.  (These false
-+positives are harmless, because they would at most cause unionfs to
-+re-validate an object that may need no revalidation, and print a debugging
-+message that clutters the console/logs.)  Therefore, to minimize the chances
-+of these situations, we delay the detection of changed times by a small
-+factor of a few seconds, called UNIONFS_MIN_CC_TIME (which defaults to 3
-+seconds, as does NFS).  This means that we will detect the change, only a
-+couple of seconds later, if indeed the time change persists in the lower
-+file object.  This delayed detection has an added performance benefit: we
-+reduce the number of times that unionfs has to revalidate objects, in case
-+there's a lot of concurrent activity on both the upper and lower objects,
-+for the same file(s).  Lastly, this delayed time attribute detection is
-+similar to how NFS clients operate (e.g., acregmin).
-+
-+Finally, there is no way currently in Linux to prevent lower directories
-+from being moved around (i.e., topology changes); there's no way to prevent
-+modifications to directory sub-trees of whole file systems which are mounted
-+read-write.  It is therefore possible for in-flight operations in unionfs to
-+take place, while a lower directory is being moved around.  Therefore, if
-+you try to, say, create a new file in a directory through unionfs, while the
-+directory is being moved around directly, then the new file may get created
-+in the new location where that directory was moved to.  This is a somewhat
-+similar behaviour in NFS: an NFS client could be creating a new file while
-+th NFS server is moving th directory around; the file will get successfully
-+created in the new location.  (The one exception in unionfs is that if the
-+branch is marked read-only by unionfs, then a copyup will take place.)
-+
-+For more information, see <http://unionfs.filesystems.org/>.
-diff --git a/Documentation/filesystems/unionfs/issues.txt b/Documentation/filesystems/unionfs/issues.txt
-new file mode 100644
-index 0000000..f4b7e7e
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/issues.txt
-@@ -0,0 +1,28 @@
-+KNOWN Unionfs 2.x ISSUES:
-+=========================
-+
-+1. Unionfs should not use lookup_one_len() on the underlying f/s as it
-+   confuses NFSv4.  Currently, unionfs_lookup() passes lookup intents to the
-+   lower file-system, this eliminates part of the problem.  The remaining
-+   calls to lookup_one_len may need to be changed to pass an intent.  We are
-+   currently introducing VFS changes to fs/namei.c's do_path_lookup() to
-+   allow proper file lookup and opening in stackable file systems.
-+
-+2. Lockdep (a debugging feature) isn't aware of stacking, and so it
-+   incorrectly complains about locking problems.  The problem boils down to
-+   this: Lockdep considers all objects of a certain type to be in the same
-+   class, for example, all inodes.  Lockdep doesn't like to see a lock held
-+   on two inodes within the same task, and warns that it could lead to a
-+   deadlock.  However, stackable file systems do precisely that: they lock
-+   an upper object, and then a lower object, in a strict order to avoid
-+   locking problems; in addition, Unionfs, as a fan-out file system, may
-+   have to lock several lower inodes.  We are currently looking into Lockdep
-+   to see how to make it aware of stackable file systems.  For now, we
-+   temporarily disable lockdep when calling vfs methods on lower objects,
-+   but only for those places where lockdep complained.  While this solution
-+   may seem unclean, it is not without precedent: other places in the kernel
-+   also do similar temporary disabling, of course after carefully having
-+   checked that it is the right thing to do.  Anyway, you get any warnings
-+   from Lockdep, please report them to the Unionfs maintainers.
-+
-+For more information, see <http://unionfs.filesystems.org/>.
-diff --git a/Documentation/filesystems/unionfs/rename.txt b/Documentation/filesystems/unionfs/rename.txt
-new file mode 100644
-index 0000000..e20bb82
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/rename.txt
-@@ -0,0 +1,31 @@
-+Rename is a complex beast. The following table shows which rename(2) operations
-+should succeed and which should fail.
-+
-+o: success
-+E: error (either unionfs or vfs)
-+X: EXDEV
-+
-+none = file does not exist
-+file = file is a file
-+dir  = file is a empty directory
-+child= file is a non-empty directory
-+wh   = file is a directory containing only whiteouts; this makes it logically
-+		empty
-+
-+                      none    file    dir     child   wh
-+file                  o       o       E       E       E
-+dir                   o       E       o       E       o
-+child                 X       E       X       E       X
-+wh                    o       E       o       E       o
-+
-+
-+Renaming directories:
-+=====================
-+
-+Whenever a empty (either physically or logically) directory is being renamed,
-+the following sequence of events should take place:
-+
-+1) Remove whiteouts from both source and destination directory
-+2) Rename source to destination
-+3) Make destination opaque to prevent anything under it from showing up
-+
-diff --git a/Documentation/filesystems/unionfs/usage.txt b/Documentation/filesystems/unionfs/usage.txt
-new file mode 100644
-index 0000000..1adde69
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/usage.txt
-@@ -0,0 +1,134 @@
-+Unionfs is a stackable unification file system, which can appear to merge
-+the contents of several directories (branches), while keeping their physical
-+content separate.  Unionfs is useful for unified source tree management,
-+merged contents of split CD-ROM, merged separate software package
-+directories, data grids, and more.  Unionfs allows any mix of read-only and
-+read-write branches, as well as insertion and deletion of branches anywhere
-+in the fan-out.  To maintain Unix semantics, Unionfs handles elimination of
-+duplicates, partial-error conditions, and more.
-+
-+GENERAL SYNTAX
-+==============
-+
-+# mount -t unionfs -o <OPTIONS>,<BRANCH-OPTIONS> none MOUNTPOINT
-+
-+OPTIONS can be any legal combination of:
-+
-+- ro		# mount file system read-only
-+- rw		# mount file system read-write
-+- remount	# remount the file system (see Branch Management below)
-+- incgen	# increment generation no. (see Cache Consistency below)
-+
-+BRANCH-OPTIONS can be either (1) a list of branches given to the "dirs="
-+option, or (2) a list of individual branch manipulation commands, combined
-+with the "remount" option, and is further described in the "Branch
-+Management" section below.
-+
-+The syntax for the "dirs=" mount option is:
-+
-+	dirs=branch[=ro|=rw][:...]
-+
-+The "dirs=" option takes a colon-delimited list of directories to compose
-+the union, with an optional branch mode for each of those directories.
-+Directories that come earlier (specified first, on the left) in the list
-+have a higher precedence than those which come later.  Additionally,
-+read-only or read-write permissions of the branch can be specified by
-+appending =ro or =rw (default) to each directory.  See the Copyup section in
-+concepts.txt, for a description of Unionfs's behavior when mixing read-only
-+and read-write branches and mounts.
-+
-+Syntax:
-+
-+	dirs=/branch1[=ro|=rw]:/branch2[=ro|=rw]:...:/branchN[=ro|=rw]
-+
-+Example:
-+
-+	dirs=/writable_branch=rw:/read-only_branch=ro
-+
-+
-+BRANCH MANAGEMENT
-+=================
-+
-+Once you mount your union for the first time, using the "dirs=" option, you
-+can then change the union's overall mode or reconfigure the branches, using
-+the remount option, as follows.
-+
-+To downgrade a union from read-write to read-only:
-+
-+# mount -t unionfs -o remount,ro none MOUNTPOINT
-+
-+To upgrade a union from read-only to read-write:
-+
-+# mount -t unionfs -o remount,rw none MOUNTPOINT
-+
-+To delete a branch /foo, regardless where it is in the current union:
-+
-+# mount -t unionfs -o remount,del=/foo none MOUNTPOINT
-+
-+To insert (add) a branch /foo before /bar:
-+
-+# mount -t unionfs -o remount,add=/bar:/foo none MOUNTPOINT
-+
-+To insert (add) a branch /foo (with the "rw" mode flag) before /bar:
-+
-+# mount -t unionfs -o remount,add=/bar:/foo=rw none MOUNTPOINT
-+
-+To insert (add) a branch /foo (in "rw" mode) at the very beginning (i.e., a
-+new highest-priority branch), you can use the above syntax, or use a short
-+hand version as follows:
-+
-+# mount -t unionfs -o remount,add=/foo none MOUNTPOINT
-+
-+To append a branch to the very end (new lowest-priority branch):
-+
-+# mount -t unionfs -o remount,add=:/foo none MOUNTPOINT
-+
-+To append a branch to the very end (new lowest-priority branch), in
-+read-only mode:
-+
-+# mount -t unionfs -o remount,add=:/foo=ro none MOUNTPOINT
-+
-+Finally, to change the mode of one existing branch, say /foo, from read-only
-+to read-write, and change /bar from read-write to read-only:
-+
-+# mount -t unionfs -o remount,mode=/foo=rw,mode=/bar=ro none MOUNTPOINT
-+
-+Note: in Unionfs 2.x, you cannot set the leftmost branch to readonly because
-+then Unionfs won't have any writable place for copyups to take place.
-+Moreover, the VFS can get confused when it tries to modify something in a
-+file system mounted read-write, but isn't permitted to write to it.
-+Instead, you should set the whole union as readonly, as described above.
-+If, however, you must set the leftmost branch as readonly, perhaps so you
-+can get a snapshot of it at a point in time, then you should insert a new
-+writable top-level branch, and mark the one you want as readonly.  This can
-+be accomplished as follows, assuming that /foo is your current leftmost
-+branch:
-+
-+# mount -t tmpfs -o size=NNN /new
-+# mount -t unionfs -o remount,add=/new,mode=/foo=ro none MOUNTPOINT
-+<do what you want safely in /foo>
-+# mount -t unionfs -o remount,del=/new,mode=/foo=rw none MOUNTPOINT
-+<check if there's anything in /new you want to preserve>
-+# umount /new
-+
-+CACHE CONSISTENCY
-+=================
-+
-+If you modify any file on any of the lower branches directly, while there is
-+a Unionfs 2.x mounted above any of those branches, you should tell Unionfs
-+to purge its caches and re-get the objects.  To do that, you have to
-+increment the generation number of the superblock using the following
-+command:
-+
-+# mount -t unionfs -o remount,incgen none MOUNTPOINT
-+
-+Note that the older way of incrementing the generation number using an
-+ioctl, is no longer supported in Unionfs 2.0 and newer.  Ioctls in general
-+are not encouraged.  Plus, an ioctl is per-file concept, whereas the
-+generation number is a per-file-system concept.  Worse, such an ioctl
-+requires an open file, which then has to be invalidated by the very nature
-+of the generation number increase (read: the old generation increase ioctl
-+was pretty racy).
-+
-+
-+For more information, see <http://unionfs.filesystems.org/>.
-diff --git a/MAINTAINERS b/MAINTAINERS
-index deedc0d..c722f8e 100644
---- a/MAINTAINERS
-+++ b/MAINTAINERS
-@@ -4173,6 +4173,14 @@ L:	linux-kernel@vger.kernel.org
- W:	http://www.kernel.dk
- S:	Maintained
- 
-+UNIONFS
-+P:	Erez Zadok
-+M:	ezk@cs.sunysb.edu
-+L:	unionfs@filesystems.org
-+W:	http://unionfs.filesystems.org
-+T:	git git.kernel.org/pub/scm/linux/kernel/git/ezk/unionfs.git
-+S:	Maintained
-+
- USB ACM DRIVER
- P:	Oliver Neukum
- M:	oliver@neukum.name
-diff --git a/fs/Kconfig b/fs/Kconfig
-index d387358..31610a2 100644
---- a/fs/Kconfig
-+++ b/fs/Kconfig
-@@ -981,6 +981,47 @@ config CONFIGFS_FS
- 
- endmenu
- 
-+menu "Layered filesystems"
-+
-+config ECRYPT_FS
-+	tristate "eCrypt filesystem layer support (EXPERIMENTAL)"
-+	depends on EXPERIMENTAL && KEYS && CRYPTO && NET
-+	help
-+	  Encrypted filesystem that operates on the VFS layer.  See
-+	  <file:Documentation/filesystems/ecryptfs.txt> to learn more about
-+	  eCryptfs.  Userspace components are required and can be
-+	  obtained from <http://ecryptfs.sf.net>.
-+
-+	  To compile this file system support as a module, choose M here: the
-+	  module will be called ecryptfs.
-+
-+config UNION_FS
-+	tristate "Union file system (EXPERIMENTAL)"
-+	depends on EXPERIMENTAL
-+	help
-+	  Unionfs is a stackable unification file system, which appears to
-+	  merge the contents of several directories (branches), while keeping
-+	  their physical content separate.
-+
-+	  See <http://unionfs.filesystems.org> for details
-+
-+config UNION_FS_XATTR
-+	bool "Unionfs extended attributes"
-+	depends on UNION_FS
-+	help
-+	  Extended attributes are name:value pairs associated with inodes by
-+	  the kernel or by users (see the attr(5) manual page).
-+
-+	  If unsure, say N.
-+
-+config UNION_FS_DEBUG
-+	bool "Debug Unionfs"
-+	depends on UNION_FS
-+	help
-+	  If you say Y here, you can turn on debugging output from Unionfs.
-+
-+endmenu
-+
- menu "Miscellaneous filesystems"
- 
- config ADFS_FS
-@@ -1033,18 +1074,6 @@ config AFFS_FS
- 	  To compile this file system support as a module, choose M here: the
- 	  module will be called affs.  If unsure, say N.
- 
--config ECRYPT_FS
--	tristate "eCrypt filesystem layer support (EXPERIMENTAL)"
--	depends on EXPERIMENTAL && KEYS && CRYPTO && NET
--	help
--	  Encrypted filesystem that operates on the VFS layer.  See
--	  <file:Documentation/filesystems/ecryptfs.txt> to learn more about
--	  eCryptfs.  Userspace components are required and can be
--	  obtained from <http://ecryptfs.sf.net>.
--
--	  To compile this file system support as a module, choose M here: the
--	  module will be called ecryptfs.
--
- config HFS_FS
- 	tristate "Apple Macintosh file system support (EXPERIMENTAL)"
- 	depends on BLOCK && EXPERIMENTAL
-diff --git a/fs/Makefile b/fs/Makefile
-index a1482a5..9bf3915 100644
---- a/fs/Makefile
-+++ b/fs/Makefile
-@@ -86,6 +86,7 @@ obj-$(CONFIG_ISO9660_FS)	+= isofs/
- obj-$(CONFIG_HFSPLUS_FS)	+= hfsplus/ # Before hfs to find wrapped HFS+
- obj-$(CONFIG_HFS_FS)		+= hfs/
- obj-$(CONFIG_ECRYPT_FS)		+= ecryptfs/
-+obj-$(CONFIG_UNION_FS)		+= unionfs/
- obj-$(CONFIG_VXFS_FS)		+= freevxfs/
- obj-$(CONFIG_NFS_FS)		+= nfs/
- obj-$(CONFIG_EXPORTFS)		+= exportfs/
-diff --git a/fs/ecryptfs/dentry.c b/fs/ecryptfs/dentry.c
-index 5e59658..4621f89 100644
---- a/fs/ecryptfs/dentry.c
-+++ b/fs/ecryptfs/dentry.c
-@@ -62,7 +62,7 @@ static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
- 		struct inode *lower_inode =
- 			ecryptfs_inode_to_lower(dentry->d_inode);
- 
--		fsstack_copy_attr_all(dentry->d_inode, lower_inode, NULL);
-+		fsstack_copy_attr_all(dentry->d_inode, lower_inode);
- 	}
- out:
- 	return rc;
-diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
-index 89209f0..d99a83e 100644
---- a/fs/ecryptfs/inode.c
-+++ b/fs/ecryptfs/inode.c
-@@ -589,9 +589,9 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
- 			lower_new_dir_dentry->d_inode, lower_new_dentry);
- 	if (rc)
- 		goto out_lock;
--	fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
-+	fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
- 	if (new_dir != old_dir)
--		fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
-+		fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
- out_lock:
- 	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
- 	dput(lower_new_dentry->d_parent);
-@@ -913,7 +913,7 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
- 	rc = notify_change(lower_dentry, ia);
- 	mutex_unlock(&lower_dentry->d_inode->i_mutex);
- out:
--	fsstack_copy_attr_all(inode, lower_inode, NULL);
-+	fsstack_copy_attr_all(inode, lower_inode);
- 	return rc;
- }
- 
-diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
-index 448dfd5..db2db5d 100644
---- a/fs/ecryptfs/main.c
-+++ b/fs/ecryptfs/main.c
-@@ -197,7 +197,7 @@ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
- 		d_add(dentry, inode);
- 	else
- 		d_instantiate(dentry, inode);
--	fsstack_copy_attr_all(inode, lower_inode, NULL);
-+	fsstack_copy_attr_all(inode, lower_inode);
- 	/* This size will be overwritten for real files w/ headers and
- 	 * other metadata */
- 	fsstack_copy_inode_size(inode, lower_inode);
-diff --git a/fs/namei.c b/fs/namei.c
-index a7b0a0b..d05ee31 100644
---- a/fs/namei.c
-+++ b/fs/namei.c
-@@ -392,6 +392,7 @@ void release_open_intent(struct nameidata *nd)
- 	else
- 		fput(nd->intent.open.file);
- }
-+EXPORT_SYMBOL_GPL(release_open_intent);
- 
- static inline struct dentry *
- do_revalidate(struct dentry *dentry, struct nameidata *nd)
-diff --git a/fs/splice.c b/fs/splice.c
-index b30311b..204bb3c 100644
---- a/fs/splice.c
-+++ b/fs/splice.c
-@@ -887,8 +887,8 @@ EXPORT_SYMBOL(generic_splice_sendpage);
- /*
-  * 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 vfs_splice_from(struct pipe_inode_info *pipe, struct file *out,
-+		     loff_t *ppos, size_t len, unsigned int flags)
- {
- 	int ret;
- 
-@@ -904,13 +904,14 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
- 
- 	return out->f_op->splice_write(pipe, out, ppos, len, flags);
- }
-+EXPORT_SYMBOL_GPL(vfs_splice_from);
- 
- /*
-  * 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 vfs_splice_to(struct file *in, loff_t *ppos,
-+		   struct pipe_inode_info *pipe, size_t len,
-+		   unsigned int flags)
- {
- 	int ret;
- 
-@@ -926,6 +927,7 @@ static long do_splice_to(struct file *in, loff_t *ppos,
- 
- 	return in->f_op->splice_read(in, ppos, pipe, len, flags);
- }
-+EXPORT_SYMBOL_GPL(vfs_splice_to);
- 
- /**
-  * splice_direct_to_actor - splices data directly between two non-pipes
-@@ -995,7 +997,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
- 		size_t read_len;
- 		loff_t pos = sd->pos, prev_pos = pos;
- 
--		ret = do_splice_to(in, &pos, pipe, len, flags);
-+		ret = vfs_splice_to(in, &pos, pipe, len, flags);
- 		if (unlikely(ret <= 0))
- 			goto out_release;
- 
-@@ -1054,7 +1056,7 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
- {
- 	struct file *file = sd->u.file;
- 
--	return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags);
-+	return vfs_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags);
- }
- 
- /**
-@@ -1128,7 +1130,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
- 		} else
- 			off = &out->f_pos;
- 
--		ret = do_splice_from(pipe, out, off, len, flags);
-+		ret = vfs_splice_from(pipe, out, off, len, flags);
- 
- 		if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
- 			ret = -EFAULT;
-@@ -1149,7 +1151,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
- 		} else
- 			off = &in->f_pos;
- 
--		ret = do_splice_to(in, off, pipe, len, flags);
-+		ret = vfs_splice_to(in, off, pipe, len, flags);
- 
- 		if (off_in && copy_to_user(off_in, off, sizeof(loff_t)))
- 			ret = -EFAULT;
-diff --git a/fs/stack.c b/fs/stack.c
-index 67716f6..a66ff6c 100644
---- a/fs/stack.c
-+++ b/fs/stack.c
-@@ -1,24 +1,82 @@
-+/*
-+ * Copyright (c) 2006-2007 Erez Zadok
-+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2006-2007 Stony Brook University
-+ * Copyright (c) 2006-2007 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
- #include <linux/module.h>
- #include <linux/fs.h>
- #include <linux/fs_stack.h>
- 
--/* does _NOT_ require i_mutex to be held.
-+/*
-+ * does _NOT_ require i_mutex to be held.
-  *
-  * This function cannot be inlined since i_size_{read,write} is rather
-  * heavy-weight on 32-bit systems
-  */
--void fsstack_copy_inode_size(struct inode *dst, const struct inode *src)
-+void fsstack_copy_inode_size(struct inode *dst, struct inode *src)
- {
--	i_size_write(dst, i_size_read((struct inode *)src));
--	dst->i_blocks = src->i_blocks;
-+	loff_t i_size;
-+	blkcnt_t i_blocks;
-+
-+	/*
-+	 * i_size_read() includes its own seqlocking and protection from
-+	 * preemption (see include/linux/fs.h): we need nothing extra for
-+	 * that here, and prefer to avoid nesting locks than attempt to
-+	 * keep i_size and i_blocks in synch together.
-+	 */
-+	i_size = i_size_read(src);
-+
-+	/*
-+	 * But if CONFIG_LSF (on 32-bit), we ought to make an effort to keep
-+	 * the two halves of i_blocks in synch despite SMP or PREEMPT - though
-+	 * stat's generic_fillattr() doesn't bother, and we won't be applying
-+	 * quotas (where i_blocks does become important) at the upper level.
-+	 *
-+	 * We don't actually know what locking is used at the lower level; but
-+	 * if it's a filesystem that supports quotas, it will be using i_lock
-+	 * as in inode_add_bytes().  tmpfs uses other locking, and its 32-bit
-+	 * is (just) able to exceed 2TB i_size with the aid of holes; but its
-+	 * i_blocks cannot carry into the upper long without almost 2TB swap -
-+	 * let's ignore that case.
-+	 */
-+	if (sizeof(i_blocks) > sizeof(long))
-+		spin_lock(&src->i_lock);
-+	i_blocks = src->i_blocks;
-+	if (sizeof(i_blocks) > sizeof(long))
-+		spin_unlock(&src->i_lock);
-+
-+	/*
-+	 * If CONFIG_SMP on 32-bit, it's vital for fsstack_copy_inode_size()
-+	 * to hold some lock around i_size_write(), otherwise i_size_read()
-+	 * may spin forever (see include/linux/fs.h).  We don't necessarily
-+	 * hold i_mutex when this is called, so take i_lock for that case.
-+	 *
-+	 * And if CONFIG_LSF (on 32-bit), continue our effort to keep the
-+	 * two halves of i_blocks in synch despite SMP or PREEMPT: use i_lock
-+	 * for that case too, and do both at once by combining the tests.
-+	 *
-+	 * There is none of this locking overhead in the 64-bit case.
-+	 */
-+	if (sizeof(i_size) > sizeof(long) || sizeof(i_blocks) > sizeof(long))
-+		spin_lock(&dst->i_lock);
-+	i_size_write(dst, i_size);
-+	dst->i_blocks = i_blocks;
-+	if (sizeof(i_size) > sizeof(long) || sizeof(i_blocks) > sizeof(long))
-+		spin_unlock(&dst->i_lock);
- }
- EXPORT_SYMBOL_GPL(fsstack_copy_inode_size);
- 
--/* copy all attributes; get_nlinks is optional way to override the i_nlink
-+/*
-+ * copy all attributes; get_nlinks is optional way to override the i_nlink
-  * copying
-  */
--void fsstack_copy_attr_all(struct inode *dest, const struct inode *src,
--				int (*get_nlinks)(struct inode *))
-+void fsstack_copy_attr_all(struct inode *dest, const struct inode *src)
- {
- 	dest->i_mode = src->i_mode;
- 	dest->i_uid = src->i_uid;
-@@ -29,14 +87,6 @@ void fsstack_copy_attr_all(struct inode *dest, const struct inode *src,
- 	dest->i_ctime = src->i_ctime;
- 	dest->i_blkbits = src->i_blkbits;
- 	dest->i_flags = src->i_flags;
--
--	/*
--	 * Update the nlinks AFTER updating the above fields, because the
--	 * get_links callback may depend on them.
--	 */
--	if (!get_nlinks)
--		dest->i_nlink = src->i_nlink;
--	else
--		dest->i_nlink = (*get_nlinks)(dest);
-+	dest->i_nlink = src->i_nlink;
- }
- EXPORT_SYMBOL_GPL(fsstack_copy_attr_all);
-diff --git a/fs/unionfs/Makefile b/fs/unionfs/Makefile
-new file mode 100644
-index 0000000..fa04e30
---- /dev/null
-+++ b/fs/unionfs/Makefile
-@@ -0,0 +1,17 @@
-+UNIONFS_VERSION="2.4 (for 2.6.27-rc1)"
-+
-+EXTRA_CFLAGS += -DUNIONFS_VERSION=\"$(UNIONFS_VERSION)\"
-+
-+obj-$(CONFIG_UNION_FS) += unionfs.o
-+
-+unionfs-y := subr.o dentry.o file.o inode.o main.o super.o \
-+	rdstate.o copyup.o dirhelper.o rename.o unlink.o \
-+	lookup.o commonfops.o dirfops.o sioq.o mmap.o whiteout.o
-+
-+unionfs-$(CONFIG_UNION_FS_XATTR) += xattr.o
-+
-+unionfs-$(CONFIG_UNION_FS_DEBUG) += debug.o
-+
-+ifeq ($(CONFIG_UNION_FS_DEBUG),y)
-+EXTRA_CFLAGS += -DDEBUG
-+endif
-diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
-new file mode 100644
-index 0000000..5861970
---- /dev/null
-+++ b/fs/unionfs/commonfops.c
-@@ -0,0 +1,905 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * 1) Copyup the file
-+ * 2) Rename the file to '.unionfs<original inode#><counter>' - obviously
-+ * stolen from NFS's silly rename
-+ */
-+static int copyup_deleted_file(struct file *file, struct dentry *dentry,
-+			       int bstart, int bindex)
-+{
-+	static unsigned int counter;
-+	const int i_inosize = sizeof(dentry->d_inode->i_ino) * 2;
-+	const int countersize = sizeof(counter) * 2;
-+	const int nlen = sizeof(".unionfs") + i_inosize + countersize - 1;
-+	char name[nlen + 1];
-+	int err;
-+	struct dentry *tmp_dentry = NULL;
-+	struct dentry *lower_dentry;
-+	struct dentry *lower_dir_dentry = NULL;
-+
-+	lower_dentry = unionfs_lower_dentry_idx(dentry, bstart);
-+
-+	sprintf(name, ".unionfs%*.*lx",
-+		i_inosize, i_inosize, lower_dentry->d_inode->i_ino);
-+
-+	/*
-+	 * Loop, looking for an unused temp name to copyup to.
-+	 *
-+	 * It's somewhat silly that we look for a free temp tmp name in the
-+	 * source branch (bstart) instead of the dest branch (bindex), where
-+	 * the final name will be created.  We _will_ catch it if somehow
-+	 * the name exists in the dest branch, but it'd be nice to catch it
-+	 * sooner than later.
-+	 */
-+retry:
-+	tmp_dentry = NULL;
-+	do {
-+		char *suffix = name + nlen - countersize;
-+
-+		dput(tmp_dentry);
-+		counter++;
-+		sprintf(suffix, "%*.*x", countersize, countersize, counter);
-+
-+		pr_debug("unionfs: trying to rename %s to %s\n",
-+			 dentry->d_name.name, name);
-+
-+		tmp_dentry = lookup_one_len(name, lower_dentry->d_parent,
-+					    nlen);
-+		if (IS_ERR(tmp_dentry)) {
-+			err = PTR_ERR(tmp_dentry);
-+			goto out;
-+		}
-+	} while (tmp_dentry->d_inode != NULL);	/* need negative dentry */
-+	dput(tmp_dentry);
-+
-+	err = copyup_named_file(dentry->d_parent->d_inode, file, name, bstart,
-+				bindex,
-+				i_size_read(file->f_path.dentry->d_inode));
-+	if (err) {
-+		if (unlikely(err == -EEXIST))
-+			goto retry;
-+		goto out;
-+	}
-+
-+	/* bring it to the same state as an unlinked file */
-+	lower_dentry = unionfs_lower_dentry_idx(dentry, dbstart(dentry));
-+	if (!unionfs_lower_inode_idx(dentry->d_inode, bindex)) {
-+		atomic_inc(&lower_dentry->d_inode->i_count);
-+		unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
-+					    lower_dentry->d_inode);
-+	}
-+	lower_dir_dentry = lock_parent(lower_dentry);
-+	err = vfs_unlink(lower_dir_dentry->d_inode, lower_dentry);
-+	unlock_dir(lower_dir_dentry);
-+
-+out:
-+	if (!err)
-+		unionfs_check_dentry(dentry);
-+	return err;
-+}
-+
-+/*
-+ * put all references held by upper struct file and free lower file pointer
-+ * array
-+ */
-+static void cleanup_file(struct file *file)
-+{
-+	int bindex, bstart, bend;
-+	struct file **lower_files;
-+	struct file *lower_file;
-+	struct super_block *sb = file->f_path.dentry->d_sb;
-+
-+	lower_files = UNIONFS_F(file)->lower_files;
-+	bstart = fbstart(file);
-+	bend = fbend(file);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		int i;	/* holds (possibly) updated branch index */
-+		int old_bid;
-+
-+		lower_file = unionfs_lower_file_idx(file, bindex);
-+		if (!lower_file)
-+			continue;
-+
-+		/*
-+		 * Find new index of matching branch with an open
-+		 * file, since branches could have been added or
-+		 * deleted causing the one with open files to shift.
-+		 */
-+		old_bid = UNIONFS_F(file)->saved_branch_ids[bindex];
-+		i = branch_id_to_idx(sb, old_bid);
-+		if (unlikely(i < 0)) {
-+			printk(KERN_ERR "unionfs: no superblock for "
-+			       "file %p\n", file);
-+			continue;
-+		}
-+
-+		/* decrement count of open files */
-+		branchput(sb, i);
-+		/*
-+		 * fput will perform an mntput for us on the correct branch.
-+		 * Although we're using the file's old branch configuration,
-+		 * bindex, which is the old index, correctly points to the
-+		 * right branch in the file's branch list.  In other words,
-+		 * we're going to mntput the correct branch even if branches
-+		 * have been added/removed.
-+		 */
-+		fput(lower_file);
-+		UNIONFS_F(file)->lower_files[bindex] = NULL;
-+		UNIONFS_F(file)->saved_branch_ids[bindex] = -1;
-+	}
-+
-+	UNIONFS_F(file)->lower_files = NULL;
-+	kfree(lower_files);
-+	kfree(UNIONFS_F(file)->saved_branch_ids);
-+	/* set to NULL because caller needs to know if to kfree on error */
-+	UNIONFS_F(file)->saved_branch_ids = NULL;
-+}
-+
-+/* open all lower files for a given file */
-+static int open_all_files(struct file *file)
-+{
-+	int bindex, bstart, bend, err = 0;
-+	struct file *lower_file;
-+	struct dentry *lower_dentry;
-+	struct dentry *dentry = file->f_path.dentry;
-+	struct super_block *sb = dentry->d_sb;
-+
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry)
-+			continue;
-+
-+		dget(lower_dentry);
-+		unionfs_mntget(dentry, bindex);
-+		branchget(sb, bindex);
-+
-+		lower_file =
-+			dentry_open(lower_dentry,
-+				    unionfs_lower_mnt_idx(dentry, bindex),
-+				    file->f_flags);
-+		if (IS_ERR(lower_file)) {
-+			err = PTR_ERR(lower_file);
-+			goto out;
-+		} else {
-+			unionfs_set_lower_file_idx(file, bindex, lower_file);
-+		}
-+	}
-+out:
-+	return err;
-+}
-+
-+/* open the highest priority file for a given upper file */
-+static int open_highest_file(struct file *file, bool willwrite)
-+{
-+	int bindex, bstart, bend, err = 0;
-+	struct file *lower_file;
-+	struct dentry *lower_dentry;
-+	struct dentry *dentry = file->f_path.dentry;
-+	struct inode *parent_inode = dentry->d_parent->d_inode;
-+	struct super_block *sb = dentry->d_sb;
-+
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+	if (willwrite && IS_WRITE_FLAG(file->f_flags) && is_robranch(dentry)) {
-+		for (bindex = bstart - 1; bindex >= 0; bindex--) {
-+			err = copyup_file(parent_inode, file, bstart, bindex,
-+					  i_size_read(dentry->d_inode));
-+			if (!err)
-+				break;
-+		}
-+		atomic_set(&UNIONFS_F(file)->generation,
-+			   atomic_read(&UNIONFS_I(dentry->d_inode)->
-+				       generation));
-+		goto out;
-+	}
-+
-+	dget(lower_dentry);
-+	unionfs_mntget(dentry, bstart);
-+	lower_file = dentry_open(lower_dentry,
-+				 unionfs_lower_mnt_idx(dentry, bstart),
-+				 file->f_flags);
-+	if (IS_ERR(lower_file)) {
-+		err = PTR_ERR(lower_file);
-+		goto out;
-+	}
-+	branchget(sb, bstart);
-+	unionfs_set_lower_file(file, lower_file);
-+	/* Fix up the position. */
-+	lower_file->f_pos = file->f_pos;
-+
-+	memcpy(&lower_file->f_ra, &file->f_ra, sizeof(struct file_ra_state));
-+out:
-+	return err;
-+}
-+
-+/* perform a delayed copyup of a read-write file on a read-only branch */
-+static int do_delayed_copyup(struct file *file)
-+{
-+	int bindex, bstart, bend, err = 0;
-+	struct dentry *dentry = file->f_path.dentry;
-+	struct inode *parent_inode = dentry->d_parent->d_inode;
-+
-+	bstart = fbstart(file);
-+	bend = fbend(file);
-+
-+	BUG_ON(!S_ISREG(dentry->d_inode->i_mode));
-+
-+	unionfs_check_file(file);
-+	for (bindex = bstart - 1; bindex >= 0; bindex--) {
-+		if (!d_deleted(dentry))
-+			err = copyup_file(parent_inode, file, bstart,
-+					  bindex,
-+					  i_size_read(dentry->d_inode));
-+		else
-+			err = copyup_deleted_file(file, dentry, bstart,
-+						  bindex);
-+		/* if succeeded, set lower open-file flags and break */
-+		if (!err) {
-+			struct file *lower_file;
-+			lower_file = unionfs_lower_file_idx(file, bindex);
-+			lower_file->f_flags = file->f_flags;
-+			break;
-+		}
-+	}
-+	if (err || (bstart <= fbstart(file)))
-+		goto out;
-+	bend = fbend(file);
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		if (unionfs_lower_file_idx(file, bindex)) {
-+			branchput(dentry->d_sb, bindex);
-+			fput(unionfs_lower_file_idx(file, bindex));
-+			unionfs_set_lower_file_idx(file, bindex, NULL);
-+		}
-+	}
-+	path_put_lowers(dentry, bstart, bend, false);
-+	iput_lowers(dentry->d_inode, bstart, bend, false);
-+	/* for reg file, we only open it "once" */
-+	fbend(file) = fbstart(file);
-+	dbend(dentry) = dbstart(dentry);
-+	ibend(dentry->d_inode) = ibstart(dentry->d_inode);
-+
-+out:
-+	unionfs_check_file(file);
-+	return err;
-+}
-+
-+/*
-+ * Helper function for unionfs_file_revalidate/locked.
-+ * Expects dentry/parent to be locked already, and revalidated.
-+ */
-+static int __unionfs_file_revalidate(struct file *file, struct dentry *dentry,
-+				     struct super_block *sb, int sbgen,
-+				     int dgen, bool willwrite)
-+{
-+	int fgen;
-+	int bstart, bend, orig_brid;
-+	int size;
-+	int err = 0;
-+
-+	fgen = atomic_read(&UNIONFS_F(file)->generation);
-+
-+	/*
-+	 * There are two cases we are interested in.  The first is if the
-+	 * generation is lower than the super-block.  The second is if
-+	 * someone has copied up this file from underneath us, we also need
-+	 * to refresh things.
-+	 */
-+	if (d_deleted(dentry) ||
-+	    (sbgen <= fgen &&
-+	     dbstart(dentry) == fbstart(file) &&
-+	     unionfs_lower_file(file)))
-+		goto out_may_copyup;
-+
-+	/* save orig branch ID */
-+	orig_brid = UNIONFS_F(file)->saved_branch_ids[fbstart(file)];
-+
-+	/* First we throw out the existing files. */
-+	cleanup_file(file);
-+
-+	/* Now we reopen the file(s) as in unionfs_open. */
-+	bstart = fbstart(file) = dbstart(dentry);
-+	bend = fbend(file) = dbend(dentry);
-+
-+	size = sizeof(struct file *) * sbmax(sb);
-+	UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL);
-+	if (unlikely(!UNIONFS_F(file)->lower_files)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+	size = sizeof(int) * sbmax(sb);
-+	UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL);
-+	if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+
-+	if (S_ISDIR(dentry->d_inode->i_mode)) {
-+		/* We need to open all the files. */
-+		err = open_all_files(file);
-+		if (err)
-+			goto out;
-+	} else {
-+		int new_brid;
-+		/* We only open the highest priority branch. */
-+		err = open_highest_file(file, willwrite);
-+		if (err)
-+			goto out;
-+		new_brid = UNIONFS_F(file)->saved_branch_ids[fbstart(file)];
-+		if (unlikely(new_brid != orig_brid && sbgen > fgen)) {
-+			/*
-+			 * If we re-opened the file on a different branch
-+			 * than the original one, and this was due to a new
-+			 * branch inserted, then update the mnt counts of
-+			 * the old and new branches accordingly.
-+			 */
-+			unionfs_mntget(dentry, bstart);
-+			unionfs_mntput(sb->s_root,
-+				       branch_id_to_idx(sb, orig_brid));
-+		}
-+		/* regular files have only one open lower file */
-+		fbend(file) = fbstart(file);
-+	}
-+	atomic_set(&UNIONFS_F(file)->generation,
-+		   atomic_read(&UNIONFS_I(dentry->d_inode)->generation));
-+
-+out_may_copyup:
-+	/* Copyup on the first write to a file on a readonly branch. */
-+	if (willwrite && IS_WRITE_FLAG(file->f_flags) &&
-+	    !IS_WRITE_FLAG(unionfs_lower_file(file)->f_flags) &&
-+	    is_robranch(dentry)) {
-+		pr_debug("unionfs: do delay copyup of \"%s\"\n",
-+			 dentry->d_name.name);
-+		err = do_delayed_copyup(file);
-+		/* regular files have only one open lower file */
-+		if (!err && !S_ISDIR(dentry->d_inode->i_mode))
-+			fbend(file) = fbstart(file);
-+	}
-+
-+out:
-+	if (err) {
-+		kfree(UNIONFS_F(file)->lower_files);
-+		kfree(UNIONFS_F(file)->saved_branch_ids);
-+	} else {
-+		unionfs_check_file(file);
-+	}
-+	return err;
-+}
-+
-+/*
-+ * Revalidate the struct file
-+ * @file: file to revalidate
-+ * @willwrite: true if caller may cause changes to the file; false otherwise.
-+ * Caller must lock/unlock dentry's branch configuration.
-+ */
-+int unionfs_file_revalidate(struct file *file, bool willwrite)
-+{
-+	struct super_block *sb;
-+	struct dentry *dentry;
-+	int sbgen, dgen;
-+	int err = 0;
-+
-+	dentry = file->f_path.dentry;
-+	sb = dentry->d_sb;
-+	verify_locked(dentry);
-+
-+	/*
-+	 * First revalidate the dentry inside struct file,
-+	 * but not unhashed dentries.
-+	 */
-+reval_dentry:
-+	if (!d_deleted(dentry) &&
-+	    !__unionfs_d_revalidate_chain(dentry, NULL, willwrite)) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	sbgen = atomic_read(&UNIONFS_SB(sb)->generation);
-+	dgen = atomic_read(&UNIONFS_D(dentry)->generation);
-+
-+	if (unlikely(sbgen > dgen)) {
-+		pr_debug("unionfs: retry dentry %s revalidation\n",
-+			 dentry->d_name.name);
-+		schedule();
-+		goto reval_dentry;
-+	}
-+	BUG_ON(sbgen > dgen);
-+
-+	err = __unionfs_file_revalidate(file, dentry, sb,
-+					sbgen, dgen, willwrite);
-+out:
-+	return err;
-+}
-+
-+/* same as unionfs_file_revalidate, but parent dentry must be locked too */
-+int unionfs_file_revalidate_locked(struct file *file, bool willwrite)
-+{
-+	struct super_block *sb;
-+	struct dentry *dentry;
-+	int sbgen, dgen;
-+	int err = 0, valid;
-+
-+	dentry = file->f_path.dentry;
-+	sb = dentry->d_sb;
-+	verify_locked(dentry);
-+	verify_locked(dentry->d_parent);
-+
-+	/* first revalidate (locked) parent, then child */
-+	valid = __unionfs_d_revalidate_chain(dentry->d_parent, NULL, false);
-+	if (unlikely(!valid)) {
-+		err = -ESTALE;	/* same as what real_lookup does */
-+		goto out;
-+	}
-+
-+reval_dentry:
-+	if (!d_deleted(dentry) &&
-+	    !__unionfs_d_revalidate_one_locked(dentry, NULL, willwrite)) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	sbgen = atomic_read(&UNIONFS_SB(sb)->generation);
-+	dgen = atomic_read(&UNIONFS_D(dentry)->generation);
-+
-+	if (unlikely(sbgen > dgen)) {
-+		pr_debug("unionfs: retry (locked) dentry %s revalidation\n",
-+			 dentry->d_name.name);
-+		schedule();
-+		goto reval_dentry;
-+	}
-+	BUG_ON(sbgen > dgen);
-+
-+	err = __unionfs_file_revalidate(file, dentry, sb,
-+					sbgen, dgen, willwrite);
-+out:
-+	return err;
-+}
-+
-+/* unionfs_open helper function: open a directory */
-+static int __open_dir(struct inode *inode, struct file *file)
-+{
-+	struct dentry *lower_dentry;
-+	struct file *lower_file;
-+	int bindex, bstart, bend;
-+	struct vfsmount *mnt;
-+
-+	bstart = fbstart(file) = dbstart(file->f_path.dentry);
-+	bend = fbend(file) = dbend(file->f_path.dentry);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry =
-+			unionfs_lower_dentry_idx(file->f_path.dentry, bindex);
-+		if (!lower_dentry)
-+			continue;
-+
-+		dget(lower_dentry);
-+		unionfs_mntget(file->f_path.dentry, bindex);
-+		mnt = unionfs_lower_mnt_idx(file->f_path.dentry, bindex);
-+		lower_file = dentry_open(lower_dentry, mnt, file->f_flags);
-+		if (IS_ERR(lower_file))
-+			return PTR_ERR(lower_file);
-+
-+		unionfs_set_lower_file_idx(file, bindex, lower_file);
-+
-+		/*
-+		 * The branchget goes after the open, because otherwise
-+		 * we would miss the reference on release.
-+		 */
-+		branchget(inode->i_sb, bindex);
-+	}
-+
-+	return 0;
-+}
-+
-+/* unionfs_open helper function: open a file */
-+static int __open_file(struct inode *inode, struct file *file)
-+{
-+	struct dentry *lower_dentry;
-+	struct file *lower_file;
-+	int lower_flags;
-+	int bindex, bstart, bend;
-+
-+	lower_dentry = unionfs_lower_dentry(file->f_path.dentry);
-+	lower_flags = file->f_flags;
-+
-+	bstart = fbstart(file) = dbstart(file->f_path.dentry);
-+	bend = fbend(file) = dbend(file->f_path.dentry);
-+
-+	/*
-+	 * check for the permission for lower file.  If the error is
-+	 * COPYUP_ERR, copyup the file.
-+	 */
-+	if (lower_dentry->d_inode && is_robranch(file->f_path.dentry)) {
-+		/*
-+		 * if the open will change the file, copy it up otherwise
-+		 * defer it.
-+		 */
-+		if (lower_flags & O_TRUNC) {
-+			int size = 0;
-+			int err = -EROFS;
-+
-+			/* copyup the file */
-+			for (bindex = bstart - 1; bindex >= 0; bindex--) {
-+				err = copyup_file(
-+					file->f_path.dentry->d_parent->d_inode,
-+					file, bstart, bindex, size);
-+				if (!err)
-+					break;
-+			}
-+			return err;
-+		} else {
-+			/*
-+			 * turn off writeable flags, to force delayed copyup
-+			 * by caller.
-+			 */
-+			lower_flags &= ~(OPEN_WRITE_FLAGS);
-+		}
-+	}
-+
-+	dget(lower_dentry);
-+
-+	/*
-+	 * dentry_open will decrement mnt refcnt if err.
-+	 * otherwise fput() will do an mntput() for us upon file close.
-+	 */
-+	unionfs_mntget(file->f_path.dentry, bstart);
-+	lower_file =
-+		dentry_open(lower_dentry,
-+			    unionfs_lower_mnt_idx(file->f_path.dentry, bstart),
-+			    lower_flags);
-+	if (IS_ERR(lower_file))
-+		return PTR_ERR(lower_file);
-+
-+	unionfs_set_lower_file(file, lower_file);
-+	branchget(inode->i_sb, bstart);
-+
-+	return 0;
-+}
-+
-+int unionfs_open(struct inode *inode, struct file *file)
-+{
-+	int err = 0;
-+	struct file *lower_file = NULL;
-+	struct dentry *dentry = file->f_path.dentry;
-+	int bindex = 0, bstart = 0, bend = 0;
-+	int size;
-+	int valid = 0;
-+
-+	unionfs_read_lock(inode->i_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	if (dentry != dentry->d_parent)
-+		unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
-+
-+	valid = __unionfs_d_revalidate_chain(dentry->d_parent, NULL, false);
-+	if (unlikely(!valid)) {
-+		err = -ESTALE;
-+		goto out_nofree;
-+	}
-+
-+	file->private_data =
-+		kzalloc(sizeof(struct unionfs_file_info), GFP_KERNEL);
-+	if (unlikely(!UNIONFS_F(file))) {
-+		err = -ENOMEM;
-+		goto out_nofree;
-+	}
-+	fbstart(file) = -1;
-+	fbend(file) = -1;
-+	atomic_set(&UNIONFS_F(file)->generation,
-+		   atomic_read(&UNIONFS_I(inode)->generation));
-+
-+	size = sizeof(struct file *) * sbmax(inode->i_sb);
-+	UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL);
-+	if (unlikely(!UNIONFS_F(file)->lower_files)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+	size = sizeof(int) * sbmax(inode->i_sb);
-+	UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL);
-+	if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+
-+	bstart = fbstart(file) = dbstart(dentry);
-+	bend = fbend(file) = dbend(dentry);
-+
-+	/*
-+	 * open all directories and make the unionfs file struct point to
-+	 * these lower file structs
-+	 */
-+	if (S_ISDIR(inode->i_mode))
-+		err = __open_dir(inode, file);	/* open a dir */
-+	else
-+		err = __open_file(inode, file);	/* open a file */
-+
-+	/* freeing the allocated resources, and fput the opened files */
-+	if (err) {
-+		for (bindex = bstart; bindex <= bend; bindex++) {
-+			lower_file = unionfs_lower_file_idx(file, bindex);
-+			if (!lower_file)
-+				continue;
-+
-+			branchput(dentry->d_sb, bindex);
-+			/* fput calls dput for lower_dentry */
-+			fput(lower_file);
-+		}
-+	}
-+
-+out:
-+	if (err) {
-+		kfree(UNIONFS_F(file)->lower_files);
-+		kfree(UNIONFS_F(file)->saved_branch_ids);
-+		kfree(UNIONFS_F(file));
-+	}
-+out_nofree:
-+	if (!err) {
-+		unionfs_postcopyup_setmnt(dentry);
-+		unionfs_copy_attr_times(inode);
-+		unionfs_check_file(file);
-+		unionfs_check_inode(inode);
-+	}
-+	if (dentry != dentry->d_parent)
-+		unionfs_unlock_dentry(dentry->d_parent);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(inode->i_sb);
-+	return err;
-+}
-+
-+/*
-+ * release all lower object references & free the file info structure
-+ *
-+ * No need to grab sb info's rwsem.
-+ */
-+int unionfs_file_release(struct inode *inode, struct file *file)
-+{
-+	struct file *lower_file = NULL;
-+	struct unionfs_file_info *fileinfo;
-+	struct unionfs_inode_info *inodeinfo;
-+	struct super_block *sb = inode->i_sb;
-+	struct dentry *dentry = file->f_path.dentry;
-+	int bindex, bstart, bend;
-+	int fgen, err = 0;
-+
-+	unionfs_read_lock(sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	/*
-+	 * Yes, we have to revalidate this file even if it's being released.
-+	 * This is important for open-but-unlinked files, as well as mmap
-+	 * support.
-+	 */
-+	err = unionfs_file_revalidate(file, UNIONFS_F(file)->wrote_to_file);
-+	if (unlikely(err))
-+		goto out;
-+	unionfs_check_file(file);
-+	fileinfo = UNIONFS_F(file);
-+	BUG_ON(file->f_path.dentry->d_inode != inode);
-+	inodeinfo = UNIONFS_I(inode);
-+
-+	/* fput all the lower files */
-+	fgen = atomic_read(&fileinfo->generation);
-+	bstart = fbstart(file);
-+	bend = fbend(file);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_file = unionfs_lower_file_idx(file, bindex);
-+
-+		if (lower_file) {
-+			unionfs_set_lower_file_idx(file, bindex, NULL);
-+			fput(lower_file);
-+			branchput(sb, bindex);
-+		}
-+
-+		/* if there are no more refs to the dentry, dput it */
-+		if (d_deleted(dentry)) {
-+			dput(unionfs_lower_dentry_idx(dentry, bindex));
-+			unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+		}
-+	}
-+
-+	kfree(fileinfo->lower_files);
-+	kfree(fileinfo->saved_branch_ids);
-+
-+	if (fileinfo->rdstate) {
-+		fileinfo->rdstate->access = jiffies;
-+		spin_lock(&inodeinfo->rdlock);
-+		inodeinfo->rdcount++;
-+		list_add_tail(&fileinfo->rdstate->cache,
-+			      &inodeinfo->readdircache);
-+		mark_inode_dirty(inode);
-+		spin_unlock(&inodeinfo->rdlock);
-+		fileinfo->rdstate = NULL;
-+	}
-+	kfree(fileinfo);
-+
-+out:
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(sb);
-+	return err;
-+}
-+
-+/* pass the ioctl to the lower fs */
-+static long do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-+{
-+	struct file *lower_file;
-+	int err;
-+
-+	lower_file = unionfs_lower_file(file);
-+
-+	err = -ENOTTY;
-+	if (!lower_file || !lower_file->f_op)
-+		goto out;
-+	if (lower_file->f_op->unlocked_ioctl) {
-+		err = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
-+	} else if (lower_file->f_op->ioctl) {
-+		lock_kernel();
-+		err = lower_file->f_op->ioctl(
-+			lower_file->f_path.dentry->d_inode,
-+			lower_file, cmd, arg);
-+		unlock_kernel();
-+	}
-+
-+out:
-+	return err;
-+}
-+
-+/*
-+ * return to user-space the branch indices containing the file in question
-+ *
-+ * We use fd_set and therefore we are limited to the number of the branches
-+ * to FD_SETSIZE, which is currently 1024 - plenty for most people
-+ */
-+static int unionfs_ioctl_queryfile(struct file *file, unsigned int cmd,
-+				   unsigned long arg)
-+{
-+	int err = 0;
-+	fd_set branchlist;
-+	int bstart = 0, bend = 0, bindex = 0;
-+	int orig_bstart, orig_bend;
-+	struct dentry *dentry, *lower_dentry;
-+	struct vfsmount *mnt;
-+
-+	dentry = file->f_path.dentry;
-+	orig_bstart = dbstart(dentry);
-+	orig_bend = dbend(dentry);
-+	err = unionfs_partial_lookup(dentry);
-+	if (err)
-+		goto out;
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+
-+	FD_ZERO(&branchlist);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry)
-+			continue;
-+		if (likely(lower_dentry->d_inode))
-+			FD_SET(bindex, &branchlist);
-+		/* purge any lower objects after partial_lookup */
-+		if (bindex < orig_bstart || bindex > orig_bend) {
-+			dput(lower_dentry);
-+			unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+			iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
-+			unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
-+						    NULL);
-+			mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+			if (!mnt)
-+				continue;
-+			unionfs_mntput(dentry, bindex);
-+			unionfs_set_lower_mnt_idx(dentry, bindex, NULL);
-+		}
-+	}
-+	/* restore original dentry's offsets */
-+	dbstart(dentry) = orig_bstart;
-+	dbend(dentry) = orig_bend;
-+	ibstart(dentry->d_inode) = orig_bstart;
-+	ibend(dentry->d_inode) = orig_bend;
-+
-+	err = copy_to_user((void __user *)arg, &branchlist, sizeof(fd_set));
-+	if (unlikely(err))
-+		err = -EFAULT;
-+
-+out:
-+	return err < 0 ? err : bend;
-+}
-+
-+long unionfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-+{
-+	long err;
-+	struct dentry *dentry = file->f_path.dentry;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	err = unionfs_file_revalidate(file, true);
-+	if (unlikely(err))
-+		goto out;
-+
-+	/* check if asked for local commands */
-+	switch (cmd) {
-+	case UNIONFS_IOCTL_INCGEN:
-+		/* Increment the superblock generation count */
-+		pr_info("unionfs: incgen ioctl deprecated; "
-+			"use \"-o remount,incgen\"\n");
-+		err = -ENOSYS;
-+		break;
-+
-+	case UNIONFS_IOCTL_QUERYFILE:
-+		/* Return list of branches containing the given file */
-+		err = unionfs_ioctl_queryfile(file, cmd, arg);
-+		break;
-+
-+	default:
-+		/* pass the ioctl down */
-+		err = do_ioctl(file, cmd, arg);
-+		break;
-+	}
-+
-+out:
-+	unionfs_check_file(file);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+int unionfs_flush(struct file *file, fl_owner_t id)
-+{
-+	int err = 0;
-+	struct file *lower_file = NULL;
-+	struct dentry *dentry = file->f_path.dentry;
-+	int bindex, bstart, bend;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	err = unionfs_file_revalidate(file, UNIONFS_F(file)->wrote_to_file);
-+	if (unlikely(err))
-+		goto out;
-+	unionfs_check_file(file);
-+
-+	bstart = fbstart(file);
-+	bend = fbend(file);
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_file = unionfs_lower_file_idx(file, bindex);
-+
-+		if (lower_file && lower_file->f_op &&
-+		    lower_file->f_op->flush) {
-+			err = lower_file->f_op->flush(lower_file, id);
-+			if (err)
-+				goto out;
-+		}
-+
-+	}
-+
-+out:
-+	if (!err)
-+		unionfs_check_file(file);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
-new file mode 100644
-index 0000000..ae6ea2b
---- /dev/null
-+++ b/fs/unionfs/copyup.c
-@@ -0,0 +1,879 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * For detailed explanation of copyup see:
-+ * Documentation/filesystems/unionfs/concepts.txt
-+ */
-+
-+#ifdef CONFIG_UNION_FS_XATTR
-+/* copyup all extended attrs for a given dentry */
-+static int copyup_xattrs(struct dentry *old_lower_dentry,
-+			 struct dentry *new_lower_dentry)
-+{
-+	int err = 0;
-+	ssize_t list_size = -1;
-+	char *name_list = NULL;
-+	char *attr_value = NULL;
-+	char *name_list_buf = NULL;
-+
-+	/* query the actual size of the xattr list */
-+	list_size = vfs_listxattr(old_lower_dentry, NULL, 0);
-+	if (list_size <= 0) {
-+		err = list_size;
-+		goto out;
-+	}
-+
-+	/* allocate space for the actual list */
-+	name_list = unionfs_xattr_alloc(list_size + 1, XATTR_LIST_MAX);
-+	if (unlikely(!name_list || IS_ERR(name_list))) {
-+		err = PTR_ERR(name_list);
-+		goto out;
-+	}
-+
-+	name_list_buf = name_list; /* save for kfree at end */
-+
-+	/* now get the actual xattr list of the source file */
-+	list_size = vfs_listxattr(old_lower_dentry, name_list, list_size);
-+	if (list_size <= 0) {
-+		err = list_size;
-+		goto out;
-+	}
-+
-+	/* allocate space to hold each xattr's value */
-+	attr_value = unionfs_xattr_alloc(XATTR_SIZE_MAX, XATTR_SIZE_MAX);
-+	if (unlikely(!attr_value || IS_ERR(attr_value))) {
-+		err = PTR_ERR(name_list);
-+		goto out;
-+	}
-+
-+	/* in a loop, get and set each xattr from src to dst file */
-+	while (*name_list) {
-+		ssize_t size;
-+
-+		/* Lock here since vfs_getxattr doesn't lock for us */
-+		mutex_lock(&old_lower_dentry->d_inode->i_mutex);
-+		size = vfs_getxattr(old_lower_dentry, name_list,
-+				    attr_value, XATTR_SIZE_MAX);
-+		mutex_unlock(&old_lower_dentry->d_inode->i_mutex);
-+		if (size < 0) {
-+			err = size;
-+			goto out;
-+		}
-+		if (size > XATTR_SIZE_MAX) {
-+			err = -E2BIG;
-+			goto out;
-+		}
-+		/* Don't lock here since vfs_setxattr does it for us. */
-+		err = vfs_setxattr(new_lower_dentry, name_list, attr_value,
-+				   size, 0);
-+		/*
-+		 * Selinux depends on "security.*" xattrs, so to maintain
-+		 * the security of copied-up files, if Selinux is active,
-+		 * then we must copy these xattrs as well.  So we need to
-+		 * temporarily get FOWNER privileges.
-+		 * XXX: move entire copyup code to SIOQ.
-+		 */
-+		if (err == -EPERM && !capable(CAP_FOWNER)) {
-+			cap_raise(current->cap_effective, CAP_FOWNER);
-+			err = vfs_setxattr(new_lower_dentry, name_list,
-+					   attr_value, size, 0);
-+			cap_lower(current->cap_effective, CAP_FOWNER);
-+		}
-+		if (err < 0)
-+			goto out;
-+		name_list += strlen(name_list) + 1;
-+	}
-+out:
-+	unionfs_xattr_kfree(name_list_buf);
-+	unionfs_xattr_kfree(attr_value);
-+	/* Ignore if xattr isn't supported */
-+	if (err == -ENOTSUPP || err == -EOPNOTSUPP)
-+		err = 0;
-+	return err;
-+}
-+#endif /* CONFIG_UNION_FS_XATTR */
-+
-+/*
-+ * Determine the mode based on the copyup flags, and the existing dentry.
-+ *
-+ * Handle file systems which may not support certain options.  For example
-+ * jffs2 doesn't allow one to chmod a symlink.  So we ignore such harmless
-+ * errors, rather than propagating them up, which results in copyup errors
-+ * and errors returned back to users.
-+ */
-+static int copyup_permissions(struct super_block *sb,
-+			      struct dentry *old_lower_dentry,
-+			      struct dentry *new_lower_dentry)
-+{
-+	struct inode *i = old_lower_dentry->d_inode;
-+	struct iattr newattrs;
-+	int err;
-+
-+	newattrs.ia_atime = i->i_atime;
-+	newattrs.ia_mtime = i->i_mtime;
-+	newattrs.ia_ctime = i->i_ctime;
-+	newattrs.ia_gid = i->i_gid;
-+	newattrs.ia_uid = i->i_uid;
-+	newattrs.ia_valid = ATTR_CTIME | ATTR_ATIME | ATTR_MTIME |
-+		ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_FORCE |
-+		ATTR_GID | ATTR_UID;
-+	mutex_lock(&new_lower_dentry->d_inode->i_mutex);
-+	err = notify_change(new_lower_dentry, &newattrs);
-+	if (err)
-+		goto out;
-+
-+	/* now try to change the mode and ignore EOPNOTSUPP on symlinks */
-+	newattrs.ia_mode = i->i_mode;
-+	newattrs.ia_valid = ATTR_MODE | ATTR_FORCE;
-+	err = notify_change(new_lower_dentry, &newattrs);
-+	if (err == -EOPNOTSUPP &&
-+	    S_ISLNK(new_lower_dentry->d_inode->i_mode)) {
-+		printk(KERN_WARNING
-+		       "unionfs: changing \"%s\" symlink mode unsupported\n",
-+		       new_lower_dentry->d_name.name);
-+		err = 0;
-+	}
-+
-+out:
-+	mutex_unlock(&new_lower_dentry->d_inode->i_mutex);
-+	return err;
-+}
-+
-+/*
-+ * create the new device/file/directory - use copyup_permission to copyup
-+ * times, and mode
-+ *
-+ * if the object being copied up is a regular file, the file is only created,
-+ * the contents have to be copied up separately
-+ */
-+static int __copyup_ndentry(struct dentry *old_lower_dentry,
-+			    struct dentry *new_lower_dentry,
-+			    struct dentry *new_lower_parent_dentry,
-+			    char *symbuf)
-+{
-+	int err = 0;
-+	umode_t old_mode = old_lower_dentry->d_inode->i_mode;
-+	struct sioq_args args;
-+
-+	if (S_ISDIR(old_mode)) {
-+		args.mkdir.parent = new_lower_parent_dentry->d_inode;
-+		args.mkdir.dentry = new_lower_dentry;
-+		args.mkdir.mode = old_mode;
-+
-+		run_sioq(__unionfs_mkdir, &args);
-+		err = args.err;
-+	} else if (S_ISLNK(old_mode)) {
-+		args.symlink.parent = new_lower_parent_dentry->d_inode;
-+		args.symlink.dentry = new_lower_dentry;
-+		args.symlink.symbuf = symbuf;
-+
-+		run_sioq(__unionfs_symlink, &args);
-+		err = args.err;
-+	} else if (S_ISBLK(old_mode) || S_ISCHR(old_mode) ||
-+		   S_ISFIFO(old_mode) || S_ISSOCK(old_mode)) {
-+		args.mknod.parent = new_lower_parent_dentry->d_inode;
-+		args.mknod.dentry = new_lower_dentry;
-+		args.mknod.mode = old_mode;
-+		args.mknod.dev = old_lower_dentry->d_inode->i_rdev;
-+
-+		run_sioq(__unionfs_mknod, &args);
-+		err = args.err;
-+	} else if (S_ISREG(old_mode)) {
-+		struct nameidata nd;
-+		err = init_lower_nd(&nd, LOOKUP_CREATE);
-+		if (unlikely(err < 0))
-+			goto out;
-+		args.create.nd = &nd;
-+		args.create.parent = new_lower_parent_dentry->d_inode;
-+		args.create.dentry = new_lower_dentry;
-+		args.create.mode = old_mode;
-+
-+		run_sioq(__unionfs_create, &args);
-+		err = args.err;
-+		release_lower_nd(&nd, err);
-+	} else {
-+		printk(KERN_CRIT "unionfs: unknown inode type %d\n",
-+		       old_mode);
-+		BUG();
-+	}
-+
-+out:
-+	return err;
-+}
-+
-+static int __copyup_reg_data(struct dentry *dentry,
-+			     struct dentry *new_lower_dentry, int new_bindex,
-+			     struct dentry *old_lower_dentry, int old_bindex,
-+			     struct file **copyup_file, loff_t len)
-+{
-+	struct super_block *sb = dentry->d_sb;
-+	struct file *input_file;
-+	struct file *output_file;
-+	struct vfsmount *output_mnt;
-+	mm_segment_t old_fs;
-+	char *buf = NULL;
-+	ssize_t read_bytes, write_bytes;
-+	loff_t size;
-+	int err = 0;
-+
-+	/* open old file */
-+	unionfs_mntget(dentry, old_bindex);
-+	branchget(sb, old_bindex);
-+	/* dentry_open calls dput and mntput if it returns an error */
-+	input_file = dentry_open(old_lower_dentry,
-+				 unionfs_lower_mnt_idx(dentry, old_bindex),
-+				 O_RDONLY | O_LARGEFILE);
-+	if (IS_ERR(input_file)) {
-+		dput(old_lower_dentry);
-+		err = PTR_ERR(input_file);
-+		goto out;
-+	}
-+	if (unlikely(!input_file->f_op || !input_file->f_op->read)) {
-+		err = -EINVAL;
-+		goto out_close_in;
-+	}
-+
-+	/* open new file */
-+	dget(new_lower_dentry);
-+	output_mnt = unionfs_mntget(sb->s_root, new_bindex);
-+	branchget(sb, new_bindex);
-+	output_file = dentry_open(new_lower_dentry, output_mnt,
-+				  O_RDWR | O_LARGEFILE);
-+	if (IS_ERR(output_file)) {
-+		err = PTR_ERR(output_file);
-+		goto out_close_in2;
-+	}
-+	if (unlikely(!output_file->f_op || !output_file->f_op->write)) {
-+		err = -EINVAL;
-+		goto out_close_out;
-+	}
-+
-+	/* allocating a buffer */
-+	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-+	if (unlikely(!buf)) {
-+		err = -ENOMEM;
-+		goto out_close_out;
-+	}
-+
-+	input_file->f_pos = 0;
-+	output_file->f_pos = 0;
-+
-+	old_fs = get_fs();
-+	set_fs(KERNEL_DS);
-+
-+	size = len;
-+	err = 0;
-+	do {
-+		if (len >= PAGE_SIZE)
-+			size = PAGE_SIZE;
-+		else if ((len < PAGE_SIZE) && (len > 0))
-+			size = len;
-+
-+		len -= PAGE_SIZE;
-+
-+		read_bytes =
-+			input_file->f_op->read(input_file,
-+					       (char __user *)buf, size,
-+					       &input_file->f_pos);
-+		if (read_bytes <= 0) {
-+			err = read_bytes;
-+			break;
-+		}
-+
-+		/* see Documentation/filesystems/unionfs/issues.txt */
-+		lockdep_off();
-+		write_bytes =
-+			output_file->f_op->write(output_file,
-+						 (char __user *)buf,
-+						 read_bytes,
-+						 &output_file->f_pos);
-+		lockdep_on();
-+		if ((write_bytes < 0) || (write_bytes < read_bytes)) {
-+			err = write_bytes;
-+			break;
-+		}
-+	} while ((read_bytes > 0) && (len > 0));
-+
-+	set_fs(old_fs);
-+
-+	kfree(buf);
-+
-+	if (!err)
-+		err = output_file->f_op->fsync(output_file,
-+					       new_lower_dentry, 0);
-+
-+	if (err)
-+		goto out_close_out;
-+
-+	if (copyup_file) {
-+		*copyup_file = output_file;
-+		goto out_close_in;
-+	}
-+
-+out_close_out:
-+	fput(output_file);
-+
-+out_close_in2:
-+	branchput(sb, new_bindex);
-+
-+out_close_in:
-+	fput(input_file);
-+
-+out:
-+	branchput(sb, old_bindex);
-+
-+	return err;
-+}
-+
-+/*
-+ * dput the lower references for old and new dentry & clear a lower dentry
-+ * pointer
-+ */
-+static void __clear(struct dentry *dentry, struct dentry *old_lower_dentry,
-+		    int old_bstart, int old_bend,
-+		    struct dentry *new_lower_dentry, int new_bindex)
-+{
-+	/* get rid of the lower dentry and all its traces */
-+	unionfs_set_lower_dentry_idx(dentry, new_bindex, NULL);
-+	dbstart(dentry) = old_bstart;
-+	dbend(dentry) = old_bend;
-+
-+	dput(new_lower_dentry);
-+	dput(old_lower_dentry);
-+}
-+
-+/*
-+ * Copy up a dentry to a file of specified name.
-+ *
-+ * @dir: used to pull the ->i_sb to access other branches
-+ * @dentry: the non-negative dentry whose lower_inode we should copy
-+ * @bstart: the branch of the lower_inode to copy from
-+ * @new_bindex: the branch to create the new file in
-+ * @name: the name of the file to create
-+ * @namelen: length of @name
-+ * @copyup_file: the "struct file" to return (optional)
-+ * @len: how many bytes to copy-up?
-+ */
-+int copyup_dentry(struct inode *dir, struct dentry *dentry, int bstart,
-+		  int new_bindex, const char *name, int namelen,
-+		  struct file **copyup_file, loff_t len)
-+{
-+	struct dentry *new_lower_dentry;
-+	struct dentry *old_lower_dentry = NULL;
-+	struct super_block *sb;
-+	int err = 0;
-+	int old_bindex;
-+	int old_bstart;
-+	int old_bend;
-+	struct dentry *new_lower_parent_dentry = NULL;
-+	mm_segment_t oldfs;
-+	char *symbuf = NULL;
-+
-+	verify_locked(dentry);
-+
-+	old_bindex = bstart;
-+	old_bstart = dbstart(dentry);
-+	old_bend = dbend(dentry);
-+
-+	BUG_ON(new_bindex < 0);
-+	BUG_ON(new_bindex >= old_bindex);
-+
-+	sb = dir->i_sb;
-+
-+	err = is_robranch_super(sb, new_bindex);
-+	if (err)
-+		goto out;
-+
-+	/* Create the directory structure above this dentry. */
-+	new_lower_dentry = create_parents(dir, dentry, name, new_bindex);
-+	if (IS_ERR(new_lower_dentry)) {
-+		err = PTR_ERR(new_lower_dentry);
-+		goto out;
-+	}
-+
-+	old_lower_dentry = unionfs_lower_dentry_idx(dentry, old_bindex);
-+	/* we conditionally dput this old_lower_dentry at end of function */
-+	dget(old_lower_dentry);
-+
-+	/* For symlinks, we must read the link before we lock the directory. */
-+	if (S_ISLNK(old_lower_dentry->d_inode->i_mode)) {
-+
-+		symbuf = kmalloc(PATH_MAX, GFP_KERNEL);
-+		if (unlikely(!symbuf)) {
-+			__clear(dentry, old_lower_dentry,
-+				old_bstart, old_bend,
-+				new_lower_dentry, new_bindex);
-+			err = -ENOMEM;
-+			goto out_free;
-+		}
-+
-+		oldfs = get_fs();
-+		set_fs(KERNEL_DS);
-+		err = old_lower_dentry->d_inode->i_op->readlink(
-+			old_lower_dentry,
-+			(char __user *)symbuf,
-+			PATH_MAX);
-+		set_fs(oldfs);
-+		if (err < 0) {
-+			__clear(dentry, old_lower_dentry,
-+				old_bstart, old_bend,
-+				new_lower_dentry, new_bindex);
-+			goto out_free;
-+		}
-+		symbuf[err] = '\0';
-+	}
-+
-+	/* Now we lock the parent, and create the object in the new branch. */
-+	new_lower_parent_dentry = lock_parent(new_lower_dentry);
-+
-+	/* create the new inode */
-+	err = __copyup_ndentry(old_lower_dentry, new_lower_dentry,
-+			       new_lower_parent_dentry, symbuf);
-+
-+	if (err) {
-+		__clear(dentry, old_lower_dentry,
-+			old_bstart, old_bend,
-+			new_lower_dentry, new_bindex);
-+		goto out_unlock;
-+	}
-+
-+	/* We actually copyup the file here. */
-+	if (S_ISREG(old_lower_dentry->d_inode->i_mode))
-+		err = __copyup_reg_data(dentry, new_lower_dentry, new_bindex,
-+					old_lower_dentry, old_bindex,
-+					copyup_file, len);
-+	if (err)
-+		goto out_unlink;
-+
-+	/* Set permissions. */
-+	err = copyup_permissions(sb, old_lower_dentry, new_lower_dentry);
-+	if (err)
-+		goto out_unlink;
-+
-+#ifdef CONFIG_UNION_FS_XATTR
-+	/* Selinux uses extended attributes for permissions. */
-+	err = copyup_xattrs(old_lower_dentry, new_lower_dentry);
-+	if (err)
-+		goto out_unlink;
-+#endif /* CONFIG_UNION_FS_XATTR */
-+
-+	/* do not allow files getting deleted to be re-interposed */
-+	if (!d_deleted(dentry))
-+		unionfs_reinterpose(dentry);
-+
-+	goto out_unlock;
-+
-+out_unlink:
-+	/*
-+	 * copyup failed, because we possibly ran out of space or
-+	 * quota, or something else happened so let's unlink; we don't
-+	 * really care about the return value of vfs_unlink
-+	 */
-+	vfs_unlink(new_lower_parent_dentry->d_inode, new_lower_dentry);
-+
-+	if (copyup_file) {
-+		/* need to close the file */
-+
-+		fput(*copyup_file);
-+		branchput(sb, new_bindex);
-+	}
-+
-+	/*
-+	 * TODO: should we reset the error to something like -EIO?
-+	 *
-+	 * If we don't reset, the user may get some nonsensical errors, but
-+	 * on the other hand, if we reset to EIO, we guarantee that the user
-+	 * will get a "confusing" error message.
-+	 */
-+
-+out_unlock:
-+	unlock_dir(new_lower_parent_dentry);
-+
-+out_free:
-+	/*
-+	 * If old_lower_dentry was not a file, then we need to dput it.  If
-+	 * it was a file, then it was already dput indirectly by other
-+	 * functions we call above which operate on regular files.
-+	 */
-+	if (old_lower_dentry && old_lower_dentry->d_inode &&
-+	    !S_ISREG(old_lower_dentry->d_inode->i_mode))
-+		dput(old_lower_dentry);
-+	kfree(symbuf);
-+
-+	if (err)
-+		goto out;
-+	if (!S_ISDIR(dentry->d_inode->i_mode)) {
-+		unionfs_postcopyup_release(dentry);
-+		if (!unionfs_lower_inode(dentry->d_inode)) {
-+			/*
-+			 * If we got here, then we copied up to an
-+			 * unlinked-open file, whose name is .unionfsXXXXX.
-+			 */
-+			struct inode *inode = new_lower_dentry->d_inode;
-+			atomic_inc(&inode->i_count);
-+			unionfs_set_lower_inode_idx(dentry->d_inode,
-+						    ibstart(dentry->d_inode),
-+						    inode);
-+		}
-+	}
-+	unionfs_postcopyup_setmnt(dentry);
-+	/* sync inode times from copied-up inode to our inode */
-+	unionfs_copy_attr_times(dentry->d_inode);
-+	unionfs_check_inode(dir);
-+	unionfs_check_dentry(dentry);
-+out:
-+	return err;
-+}
-+
-+/*
-+ * This function creates a copy of a file represented by 'file' which
-+ * currently resides in branch 'bstart' to branch 'new_bindex.'  The copy
-+ * will be named "name".
-+ */
-+int copyup_named_file(struct inode *dir, struct file *file, char *name,
-+		      int bstart, int new_bindex, loff_t len)
-+{
-+	int err = 0;
-+	struct file *output_file = NULL;
-+
-+	err = copyup_dentry(dir, file->f_path.dentry, bstart, new_bindex,
-+			    name, strlen(name), &output_file, len);
-+	if (!err) {
-+		fbstart(file) = new_bindex;
-+		unionfs_set_lower_file_idx(file, new_bindex, output_file);
-+	}
-+
-+	return err;
-+}
-+
-+/*
-+ * This function creates a copy of a file represented by 'file' which
-+ * currently resides in branch 'bstart' to branch 'new_bindex'.
-+ */
-+int copyup_file(struct inode *dir, struct file *file, int bstart,
-+		int new_bindex, loff_t len)
-+{
-+	int err = 0;
-+	struct file *output_file = NULL;
-+	struct dentry *dentry = file->f_path.dentry;
-+
-+	err = copyup_dentry(dir, dentry, bstart, new_bindex,
-+			    dentry->d_name.name, dentry->d_name.len,
-+			    &output_file, len);
-+	if (!err) {
-+		fbstart(file) = new_bindex;
-+		unionfs_set_lower_file_idx(file, new_bindex, output_file);
-+	}
-+
-+	return err;
-+}
-+
-+/* purge a dentry's lower-branch states (dput/mntput, etc.) */
-+static void __cleanup_dentry(struct dentry *dentry, int bindex,
-+			     int old_bstart, int old_bend)
-+{
-+	int loop_start;
-+	int loop_end;
-+	int new_bstart = -1;
-+	int new_bend = -1;
-+	int i;
-+
-+	loop_start = min(old_bstart, bindex);
-+	loop_end = max(old_bend, bindex);
-+
-+	/*
-+	 * This loop sets the bstart and bend for the new dentry by
-+	 * traversing from left to right.  It also dputs all negative
-+	 * dentries except bindex
-+	 */
-+	for (i = loop_start; i <= loop_end; i++) {
-+		if (!unionfs_lower_dentry_idx(dentry, i))
-+			continue;
-+
-+		if (i == bindex) {
-+			new_bend = i;
-+			if (new_bstart < 0)
-+				new_bstart = i;
-+			continue;
-+		}
-+
-+		if (!unionfs_lower_dentry_idx(dentry, i)->d_inode) {
-+			dput(unionfs_lower_dentry_idx(dentry, i));
-+			unionfs_set_lower_dentry_idx(dentry, i, NULL);
-+
-+			unionfs_mntput(dentry, i);
-+			unionfs_set_lower_mnt_idx(dentry, i, NULL);
-+		} else {
-+			if (new_bstart < 0)
-+				new_bstart = i;
-+			new_bend = i;
-+		}
-+	}
-+
-+	if (new_bstart < 0)
-+		new_bstart = bindex;
-+	if (new_bend < 0)
-+		new_bend = bindex;
-+	dbstart(dentry) = new_bstart;
-+	dbend(dentry) = new_bend;
-+
-+}
-+
-+/* set lower inode ptr and update bstart & bend if necessary */
-+static void __set_inode(struct dentry *upper, struct dentry *lower,
-+			int bindex)
-+{
-+	unionfs_set_lower_inode_idx(upper->d_inode, bindex,
-+				    igrab(lower->d_inode));
-+	if (likely(ibstart(upper->d_inode) > bindex))
-+		ibstart(upper->d_inode) = bindex;
-+	if (likely(ibend(upper->d_inode) < bindex))
-+		ibend(upper->d_inode) = bindex;
-+
-+}
-+
-+/* set lower dentry ptr and update bstart & bend if necessary */
-+static void __set_dentry(struct dentry *upper, struct dentry *lower,
-+			 int bindex)
-+{
-+	unionfs_set_lower_dentry_idx(upper, bindex, lower);
-+	if (likely(dbstart(upper) > bindex))
-+		dbstart(upper) = bindex;
-+	if (likely(dbend(upper) < bindex))
-+		dbend(upper) = bindex;
-+}
-+
-+/*
-+ * This function replicates the directory structure up-to given dentry
-+ * in the bindex branch.
-+ */
-+struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
-+			      const char *name, int bindex)
-+{
-+	int err;
-+	struct dentry *child_dentry;
-+	struct dentry *parent_dentry;
-+	struct dentry *lower_parent_dentry = NULL;
-+	struct dentry *lower_dentry = NULL;
-+	const char *childname;
-+	unsigned int childnamelen;
-+	int nr_dentry;
-+	int count = 0;
-+	int old_bstart;
-+	int old_bend;
-+	struct dentry **path = NULL;
-+	struct super_block *sb;
-+
-+	verify_locked(dentry);
-+
-+	err = is_robranch_super(dir->i_sb, bindex);
-+	if (err) {
-+		lower_dentry = ERR_PTR(err);
-+		goto out;
-+	}
-+
-+	old_bstart = dbstart(dentry);
-+	old_bend = dbend(dentry);
-+
-+	lower_dentry = ERR_PTR(-ENOMEM);
-+
-+	/* There is no sense allocating any less than the minimum. */
-+	nr_dentry = 1;
-+	path = kmalloc(nr_dentry * sizeof(struct dentry *), GFP_KERNEL);
-+	if (unlikely(!path))
-+		goto out;
-+
-+	/* assume the negative dentry of unionfs as the parent dentry */
-+	parent_dentry = dentry;
-+
-+	/*
-+	 * This loop finds the first parent that exists in the given branch.
-+	 * We start building the directory structure from there.  At the end
-+	 * of the loop, the following should hold:
-+	 *  - child_dentry is the first nonexistent child
-+	 *  - parent_dentry is the first existent parent
-+	 *  - path[0] is the = deepest child
-+	 *  - path[count] is the first child to create
-+	 */
-+	do {
-+		child_dentry = parent_dentry;
-+
-+		/* find the parent directory dentry in unionfs */
-+		parent_dentry = dget_parent(child_dentry);
-+
-+		/* find out the lower_parent_dentry in the given branch */
-+		lower_parent_dentry =
-+			unionfs_lower_dentry_idx(parent_dentry, bindex);
-+
-+		/* grow path table */
-+		if (count == nr_dentry) {
-+			void *p;
-+
-+			nr_dentry *= 2;
-+			p = krealloc(path, nr_dentry * sizeof(struct dentry *),
-+				     GFP_KERNEL);
-+			if (unlikely(!p)) {
-+				lower_dentry = ERR_PTR(-ENOMEM);
-+				goto out;
-+			}
-+			path = p;
-+		}
-+
-+		/* store the child dentry */
-+		path[count++] = child_dentry;
-+	} while (!lower_parent_dentry);
-+	count--;
-+
-+	sb = dentry->d_sb;
-+
-+	/*
-+	 * This code goes between the begin/end labels and basically
-+	 * emulates a while(child_dentry != dentry), only cleaner and
-+	 * shorter than what would be a much longer while loop.
-+	 */
-+begin:
-+	/* get lower parent dir in the current branch */
-+	lower_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
-+	dput(parent_dentry);
-+
-+	/* init the values to lookup */
-+	childname = child_dentry->d_name.name;
-+	childnamelen = child_dentry->d_name.len;
-+
-+	if (child_dentry != dentry) {
-+		/* lookup child in the underlying file system */
-+		lower_dentry = lookup_one_len(childname, lower_parent_dentry,
-+					      childnamelen);
-+		if (IS_ERR(lower_dentry))
-+			goto out;
-+	} else {
-+		/*
-+		 * Is the name a whiteout of the child name ?  lookup the
-+		 * whiteout child in the underlying file system
-+		 */
-+		lower_dentry = lookup_one_len(name, lower_parent_dentry,
-+					      strlen(name));
-+		if (IS_ERR(lower_dentry))
-+			goto out;
-+
-+		/* Replace the current dentry (if any) with the new one */
-+		dput(unionfs_lower_dentry_idx(dentry, bindex));
-+		unionfs_set_lower_dentry_idx(dentry, bindex,
-+					     lower_dentry);
-+
-+		__cleanup_dentry(dentry, bindex, old_bstart, old_bend);
-+		goto out;
-+	}
-+
-+	if (lower_dentry->d_inode) {
-+		/*
-+		 * since this already exists we dput to avoid
-+		 * multiple references on the same dentry
-+		 */
-+		dput(lower_dentry);
-+	} else {
-+		struct sioq_args args;
-+
-+		/* it's a negative dentry, create a new dir */
-+		lower_parent_dentry = lock_parent(lower_dentry);
-+
-+		args.mkdir.parent = lower_parent_dentry->d_inode;
-+		args.mkdir.dentry = lower_dentry;
-+		args.mkdir.mode = child_dentry->d_inode->i_mode;
-+
-+		run_sioq(__unionfs_mkdir, &args);
-+		err = args.err;
-+
-+		if (!err)
-+			err = copyup_permissions(dir->i_sb, child_dentry,
-+						 lower_dentry);
-+		unlock_dir(lower_parent_dentry);
-+		if (err) {
-+			dput(lower_dentry);
-+			lower_dentry = ERR_PTR(err);
-+			goto out;
-+		}
-+
-+	}
-+
-+	__set_inode(child_dentry, lower_dentry, bindex);
-+	__set_dentry(child_dentry, lower_dentry, bindex);
-+	/*
-+	 * update times of this dentry, but also the parent, because if
-+	 * we changed, the parent may have changed too.
-+	 */
-+	fsstack_copy_attr_times(parent_dentry->d_inode,
-+				lower_parent_dentry->d_inode);
-+	unionfs_copy_attr_times(child_dentry->d_inode);
-+
-+	parent_dentry = child_dentry;
-+	child_dentry = path[--count];
-+	goto begin;
-+out:
-+	/* cleanup any leftover locks from the do/while loop above */
-+	if (IS_ERR(lower_dentry))
-+		while (count)
-+			dput(path[count--]);
-+	kfree(path);
-+	return lower_dentry;
-+}
-+
-+/*
-+ * Post-copyup helper to ensure we have valid mnts: set lower mnt of
-+ * dentry+parents to the first parent node that has an mnt.
-+ */
-+void unionfs_postcopyup_setmnt(struct dentry *dentry)
-+{
-+	struct dentry *parent, *hasone;
-+	int bindex = dbstart(dentry);
-+
-+	if (unionfs_lower_mnt_idx(dentry, bindex))
-+		return;
-+	hasone = dentry->d_parent;
-+	/* this loop should stop at root dentry */
-+	while (!unionfs_lower_mnt_idx(hasone, bindex))
-+		hasone = hasone->d_parent;
-+	parent = dentry;
-+	while (!unionfs_lower_mnt_idx(parent, bindex)) {
-+		unionfs_set_lower_mnt_idx(parent, bindex,
-+					  unionfs_mntget(hasone, bindex));
-+		parent = parent->d_parent;
-+	}
-+}
-+
-+/*
-+ * Post-copyup helper to release all non-directory source objects of a
-+ * copied-up file.  Regular files should have only one lower object.
-+ */
-+void unionfs_postcopyup_release(struct dentry *dentry)
-+{
-+	int bstart, bend;
-+
-+	BUG_ON(S_ISDIR(dentry->d_inode->i_mode));
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+
-+	path_put_lowers(dentry, bstart + 1, bend, false);
-+	iput_lowers(dentry->d_inode, bstart + 1, bend, false);
-+
-+	dbend(dentry) = bstart;
-+	ibend(dentry->d_inode) = ibstart(dentry->d_inode) = bstart;
-+}
-diff --git a/fs/unionfs/debug.c b/fs/unionfs/debug.c
-new file mode 100644
-index 0000000..db62d22
---- /dev/null
-+++ b/fs/unionfs/debug.c
-@@ -0,0 +1,533 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Helper debugging functions for maintainers (and for users to report back
-+ * useful information back to maintainers)
-+ */
-+
-+/* it's always useful to know what part of the code called us */
-+#define PRINT_CALLER(fname, fxn, line)					\
-+	do {								\
-+		if (!printed_caller) {					\
-+			pr_debug("PC:%s:%s:%d\n", (fname), (fxn), (line)); \
-+			printed_caller = 1;				\
-+		}							\
-+	} while (0)
-+
-+/*
-+ * __unionfs_check_{inode,dentry,file} perform exhaustive sanity checking on
-+ * the fan-out of various Unionfs objects.  We check that no lower objects
-+ * exist  outside the start/end branch range; that all objects within are
-+ * non-NULL (with some allowed exceptions); that for every lower file
-+ * there's a lower dentry+inode; that the start/end ranges match for all
-+ * corresponding lower objects; that open files/symlinks have only one lower
-+ * objects, but directories can have several; and more.
-+ */
-+void __unionfs_check_inode(const struct inode *inode,
-+			   const char *fname, const char *fxn, int line)
-+{
-+	int bindex;
-+	int istart, iend;
-+	struct inode *lower_inode;
-+	struct super_block *sb;
-+	int printed_caller = 0;
-+	void *poison_ptr;
-+
-+	/* for inodes now */
-+	BUG_ON(!inode);
-+	sb = inode->i_sb;
-+	istart = ibstart(inode);
-+	iend = ibend(inode);
-+	/* don't check inode if no lower branches */
-+	if (istart < 0 && iend < 0)
-+		return;
-+	if (unlikely(istart > iend)) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" Ci0: inode=%p istart/end=%d:%d\n",
-+			 inode, istart, iend);
-+	}
-+	if (unlikely((istart == -1 && iend != -1) ||
-+		     (istart != -1 && iend == -1))) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" Ci1: inode=%p istart/end=%d:%d\n",
-+			 inode, istart, iend);
-+	}
-+	if (!S_ISDIR(inode->i_mode)) {
-+		if (unlikely(iend != istart)) {
-+			PRINT_CALLER(fname, fxn, line);
-+			pr_debug(" Ci2: inode=%p istart=%d iend=%d\n",
-+				 inode, istart, iend);
-+		}
-+	}
-+
-+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+		if (unlikely(!UNIONFS_I(inode))) {
-+			PRINT_CALLER(fname, fxn, line);
-+			pr_debug(" Ci3: no inode_info %p\n", inode);
-+			return;
-+		}
-+		if (unlikely(!UNIONFS_I(inode)->lower_inodes)) {
-+			PRINT_CALLER(fname, fxn, line);
-+			pr_debug(" Ci4: no lower_inodes %p\n", inode);
-+			return;
-+		}
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (lower_inode) {
-+			memset(&poison_ptr, POISON_INUSE, sizeof(void *));
-+			if (unlikely(bindex < istart || bindex > iend)) {
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" Ci5: inode/linode=%p:%p bindex=%d "
-+					 "istart/end=%d:%d\n", inode,
-+					 lower_inode, bindex, istart, iend);
-+			} else if (unlikely(lower_inode == poison_ptr)) {
-+				/* freed inode! */
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" Ci6: inode/linode=%p:%p bindex=%d "
-+					 "istart/end=%d:%d\n", inode,
-+					 lower_inode, bindex, istart, iend);
-+			}
-+			continue;
-+		}
-+		/* if we get here, then lower_inode == NULL */
-+		if (bindex < istart || bindex > iend)
-+			continue;
-+		/*
-+		 * directories can have NULL lower inodes in b/t start/end,
-+		 * but NOT if at the start/end range.
-+		 */
-+		if (unlikely(S_ISDIR(inode->i_mode) &&
-+			     bindex > istart && bindex < iend))
-+			continue;
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" Ci7: inode/linode=%p:%p "
-+			 "bindex=%d istart/end=%d:%d\n",
-+			 inode, lower_inode, bindex, istart, iend);
-+	}
-+}
-+
-+void __unionfs_check_dentry(const struct dentry *dentry,
-+			    const char *fname, const char *fxn, int line)
-+{
-+	int bindex;
-+	int dstart, dend, istart, iend;
-+	struct dentry *lower_dentry;
-+	struct inode *inode, *lower_inode;
-+	struct super_block *sb;
-+	struct vfsmount *lower_mnt;
-+	int printed_caller = 0;
-+	void *poison_ptr;
-+
-+	BUG_ON(!dentry);
-+	sb = dentry->d_sb;
-+	inode = dentry->d_inode;
-+	dstart = dbstart(dentry);
-+	dend = dbend(dentry);
-+	/* don't check dentry/mnt if no lower branches */
-+	if (dstart < 0 && dend < 0)
-+		goto check_inode;
-+	BUG_ON(dstart > dend);
-+
-+	if (unlikely((dstart == -1 && dend != -1) ||
-+		     (dstart != -1 && dend == -1))) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" CD0: dentry=%p dstart/end=%d:%d\n",
-+			 dentry, dstart, dend);
-+	}
-+	/*
-+	 * check for NULL dentries inside the start/end range, or
-+	 * non-NULL dentries outside the start/end range.
-+	 */
-+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (lower_dentry) {
-+			if (unlikely(bindex < dstart || bindex > dend)) {
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" CD1: dentry/lower=%p:%p(%p) "
-+					 "bindex=%d dstart/end=%d:%d\n",
-+					 dentry, lower_dentry,
-+					 (lower_dentry ? lower_dentry->d_inode :
-+					  (void *) -1L),
-+					 bindex, dstart, dend);
-+			}
-+		} else {	/* lower_dentry == NULL */
-+			if (bindex < dstart || bindex > dend)
-+				continue;
-+			/*
-+			 * Directories can have NULL lower inodes in b/t
-+			 * start/end, but NOT if at the start/end range.
-+			 * Ignore this rule, however, if this is a NULL
-+			 * dentry or a deleted dentry.
-+			 */
-+			if (unlikely(!d_deleted((struct dentry *) dentry) &&
-+				     inode &&
-+				     !(inode && S_ISDIR(inode->i_mode) &&
-+				       bindex > dstart && bindex < dend))) {
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" CD2: dentry/lower=%p:%p(%p) "
-+					 "bindex=%d dstart/end=%d:%d\n",
-+					 dentry, lower_dentry,
-+					 (lower_dentry ?
-+					  lower_dentry->d_inode :
-+					  (void *) -1L),
-+					 bindex, dstart, dend);
-+			}
-+		}
-+	}
-+
-+	/* check for vfsmounts same as for dentries */
-+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+		lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+		if (lower_mnt) {
-+			if (unlikely(bindex < dstart || bindex > dend)) {
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" CM0: dentry/lmnt=%p:%p bindex=%d "
-+					 "dstart/end=%d:%d\n", dentry,
-+					 lower_mnt, bindex, dstart, dend);
-+			}
-+		} else {	/* lower_mnt == NULL */
-+			if (bindex < dstart || bindex > dend)
-+				continue;
-+			/*
-+			 * Directories can have NULL lower inodes in b/t
-+			 * start/end, but NOT if at the start/end range.
-+			 * Ignore this rule, however, if this is a NULL
-+			 * dentry.
-+			 */
-+			if (unlikely(inode &&
-+				     !(inode && S_ISDIR(inode->i_mode) &&
-+				       bindex > dstart && bindex < dend))) {
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" CM1: dentry/lmnt=%p:%p "
-+					 "bindex=%d dstart/end=%d:%d\n",
-+					 dentry, lower_mnt, bindex,
-+					 dstart, dend);
-+			}
-+		}
-+	}
-+
-+check_inode:
-+	/* for inodes now */
-+	if (!inode)
-+		return;
-+	istart = ibstart(inode);
-+	iend = ibend(inode);
-+	/* don't check inode if no lower branches */
-+	if (istart < 0 && iend < 0)
-+		return;
-+	BUG_ON(istart > iend);
-+	if (unlikely((istart == -1 && iend != -1) ||
-+		     (istart != -1 && iend == -1))) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" CI0: dentry/inode=%p:%p istart/end=%d:%d\n",
-+			 dentry, inode, istart, iend);
-+	}
-+	if (unlikely(istart != dstart)) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" CI1: dentry/inode=%p:%p istart=%d dstart=%d\n",
-+			 dentry, inode, istart, dstart);
-+	}
-+	if (unlikely(iend != dend)) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" CI2: dentry/inode=%p:%p iend=%d dend=%d\n",
-+			 dentry, inode, iend, dend);
-+	}
-+
-+	if (!S_ISDIR(inode->i_mode)) {
-+		if (unlikely(dend != dstart)) {
-+			PRINT_CALLER(fname, fxn, line);
-+			pr_debug(" CI3: dentry/inode=%p:%p dstart=%d dend=%d\n",
-+				 dentry, inode, dstart, dend);
-+		}
-+		if (unlikely(iend != istart)) {
-+			PRINT_CALLER(fname, fxn, line);
-+			pr_debug(" CI4: dentry/inode=%p:%p istart=%d iend=%d\n",
-+				 dentry, inode, istart, iend);
-+		}
-+	}
-+
-+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (lower_inode) {
-+			memset(&poison_ptr, POISON_INUSE, sizeof(void *));
-+			if (unlikely(bindex < istart || bindex > iend)) {
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" CI5: dentry/linode=%p:%p bindex=%d "
-+					 "istart/end=%d:%d\n", dentry,
-+					 lower_inode, bindex, istart, iend);
-+			} else if (unlikely(lower_inode == poison_ptr)) {
-+				/* freed inode! */
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" CI6: dentry/linode=%p:%p bindex=%d "
-+					 "istart/end=%d:%d\n", dentry,
-+					 lower_inode, bindex, istart, iend);
-+			}
-+			continue;
-+		}
-+		/* if we get here, then lower_inode == NULL */
-+		if (bindex < istart || bindex > iend)
-+			continue;
-+		/*
-+		 * directories can have NULL lower inodes in b/t start/end,
-+		 * but NOT if at the start/end range.
-+		 */
-+		if (unlikely(S_ISDIR(inode->i_mode) &&
-+			     bindex > istart && bindex < iend))
-+			continue;
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" CI7: dentry/linode=%p:%p "
-+			 "bindex=%d istart/end=%d:%d\n",
-+			 dentry, lower_inode, bindex, istart, iend);
-+	}
-+
-+	/*
-+	 * If it's a directory, then intermediate objects b/t start/end can
-+	 * be NULL.  But, check that all three are NULL: lower dentry, mnt,
-+	 * and inode.
-+	 */
-+	if (dstart >= 0 && dend >= 0 && S_ISDIR(inode->i_mode))
-+		for (bindex = dstart+1; bindex < dend; bindex++) {
-+			lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+			lower_dentry = unionfs_lower_dentry_idx(dentry,
-+								bindex);
-+			lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+			if (unlikely(!((lower_inode && lower_dentry &&
-+					lower_mnt) ||
-+				       (!lower_inode &&
-+					!lower_dentry && !lower_mnt)))) {
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" Cx: lmnt/ldentry/linode=%p:%p:%p "
-+					 "bindex=%d dstart/end=%d:%d\n",
-+					 lower_mnt, lower_dentry, lower_inode,
-+					 bindex, dstart, dend);
-+			}
-+		}
-+	/* check if lower inode is newer than upper one (it shouldn't) */
-+	if (unlikely(is_newer_lower(dentry) && !is_negative_lower(dentry))) {
-+		PRINT_CALLER(fname, fxn, line);
-+		for (bindex = ibstart(inode); bindex <= ibend(inode);
-+		     bindex++) {
-+			lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+			if (unlikely(!lower_inode))
-+				continue;
-+			pr_debug(" CI8: bindex=%d mtime/lmtime=%lu.%lu/%lu.%lu "
-+				 "ctime/lctime=%lu.%lu/%lu.%lu\n",
-+				 bindex,
-+				 inode->i_mtime.tv_sec,
-+				 inode->i_mtime.tv_nsec,
-+				 lower_inode->i_mtime.tv_sec,
-+				 lower_inode->i_mtime.tv_nsec,
-+				 inode->i_ctime.tv_sec,
-+				 inode->i_ctime.tv_nsec,
-+				 lower_inode->i_ctime.tv_sec,
-+				 lower_inode->i_ctime.tv_nsec);
-+		}
-+	}
-+}
-+
-+void __unionfs_check_file(const struct file *file,
-+			  const char *fname, const char *fxn, int line)
-+{
-+	int bindex;
-+	int dstart, dend, fstart, fend;
-+	struct dentry *dentry;
-+	struct file *lower_file;
-+	struct inode *inode;
-+	struct super_block *sb;
-+	int printed_caller = 0;
-+
-+	BUG_ON(!file);
-+	dentry = file->f_path.dentry;
-+	sb = dentry->d_sb;
-+	dstart = dbstart(dentry);
-+	dend = dbend(dentry);
-+	BUG_ON(dstart > dend);
-+	fstart = fbstart(file);
-+	fend = fbend(file);
-+	BUG_ON(fstart > fend);
-+
-+	if (unlikely((fstart == -1 && fend != -1) ||
-+		     (fstart != -1 && fend == -1))) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" CF0: file/dentry=%p:%p fstart/end=%d:%d\n",
-+			 file, dentry, fstart, fend);
-+	}
-+	if (unlikely(fstart != dstart)) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" CF1: file/dentry=%p:%p fstart=%d dstart=%d\n",
-+			 file, dentry, fstart, dstart);
-+	}
-+	if (unlikely(fend != dend)) {
-+		PRINT_CALLER(fname, fxn, line);
-+		pr_debug(" CF2: file/dentry=%p:%p fend=%d dend=%d\n",
-+			 file, dentry, fend, dend);
-+	}
-+	inode = dentry->d_inode;
-+	if (!S_ISDIR(inode->i_mode)) {
-+		if (unlikely(fend != fstart)) {
-+			PRINT_CALLER(fname, fxn, line);
-+			pr_debug(" CF3: file/inode=%p:%p fstart=%d fend=%d\n",
-+				 file, inode, fstart, fend);
-+		}
-+		if (unlikely(dend != dstart)) {
-+			PRINT_CALLER(fname, fxn, line);
-+			pr_debug(" CF4: file/dentry=%p:%p dstart=%d dend=%d\n",
-+				 file, dentry, dstart, dend);
-+		}
-+	}
-+
-+	/*
-+	 * check for NULL dentries inside the start/end range, or
-+	 * non-NULL dentries outside the start/end range.
-+	 */
-+	for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+		lower_file = unionfs_lower_file_idx(file, bindex);
-+		if (lower_file) {
-+			if (unlikely(bindex < fstart || bindex > fend)) {
-+				PRINT_CALLER(fname, fxn, line);
-+				pr_debug(" CF5: file/lower=%p:%p bindex=%d "
-+					 "fstart/end=%d:%d\n", file,
-+					 lower_file, bindex, fstart, fend);
-+			}
-+		} else {	/* lower_file == NULL */
-+			if (bindex >= fstart && bindex <= fend) {
-+				/*
-+				 * directories can have NULL lower inodes in
-+				 * b/t start/end, but NOT if at the
-+				 * start/end range.
-+				 */
-+				if (unlikely(!(S_ISDIR(inode->i_mode) &&
-+					       bindex > fstart &&
-+					       bindex < fend))) {
-+					PRINT_CALLER(fname, fxn, line);
-+					pr_debug(" CF6: file/lower=%p:%p "
-+						 "bindex=%d fstart/end=%d:%d\n",
-+						 file, lower_file, bindex,
-+						 fstart, fend);
-+				}
-+			}
-+		}
-+	}
-+
-+	__unionfs_check_dentry(dentry, fname, fxn, line);
-+}
-+
-+void __unionfs_check_nd(const struct nameidata *nd,
-+			const char *fname, const char *fxn, int line)
-+{
-+	struct file *file;
-+	int printed_caller = 0;
-+
-+	if (unlikely(!nd))
-+		return;
-+	if (nd->flags & LOOKUP_OPEN) {
-+		file = nd->intent.open.file;
-+		if (unlikely(file->f_path.dentry &&
-+			     strcmp(file->f_path.dentry->d_sb->s_type->name,
-+				    UNIONFS_NAME))) {
-+			PRINT_CALLER(fname, fxn, line);
-+			pr_debug(" CND1: lower_file of type %s\n",
-+				 file->f_path.dentry->d_sb->s_type->name);
-+			BUG();
-+		}
-+	}
-+}
-+
-+/* useful to track vfsmount leaks that could cause EBUSY on unmount */
-+void __show_branch_counts(const struct super_block *sb,
-+			  const char *file, const char *fxn, int line)
-+{
-+	int i;
-+	struct vfsmount *mnt;
-+
-+	pr_debug("BC:");
-+	for (i = 0; i < sbmax(sb); i++) {
-+		if (likely(sb->s_root))
-+			mnt = UNIONFS_D(sb->s_root)->lower_paths[i].mnt;
-+		else
-+			mnt = NULL;
-+		printk(KERN_CONT "%d:",
-+		       (mnt ? atomic_read(&mnt->mnt_count) : -99));
-+	}
-+	printk(KERN_CONT "%s:%s:%d\n", file, fxn, line);
-+}
-+
-+void __show_inode_times(const struct inode *inode,
-+			const char *file, const char *fxn, int line)
-+{
-+	struct inode *lower_inode;
-+	int bindex;
-+
-+	for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (unlikely(!lower_inode))
-+			continue;
-+		pr_debug("IT(%lu:%d): %s:%s:%d "
-+			 "um=%lu/%lu lm=%lu/%lu uc=%lu/%lu lc=%lu/%lu\n",
-+			 inode->i_ino, bindex,
-+			 file, fxn, line,
-+			 inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
-+			 lower_inode->i_mtime.tv_sec,
-+			 lower_inode->i_mtime.tv_nsec,
-+			 inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
-+			 lower_inode->i_ctime.tv_sec,
-+			 lower_inode->i_ctime.tv_nsec);
-+	}
-+}
-+
-+void __show_dinode_times(const struct dentry *dentry,
-+			const char *file, const char *fxn, int line)
-+{
-+	struct inode *inode = dentry->d_inode;
-+	struct inode *lower_inode;
-+	int bindex;
-+
-+	for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (!lower_inode)
-+			continue;
-+		pr_debug("DT(%s:%lu:%d): %s:%s:%d "
-+			 "um=%lu/%lu lm=%lu/%lu uc=%lu/%lu lc=%lu/%lu\n",
-+			 dentry->d_name.name, inode->i_ino, bindex,
-+			 file, fxn, line,
-+			 inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
-+			 lower_inode->i_mtime.tv_sec,
-+			 lower_inode->i_mtime.tv_nsec,
-+			 inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
-+			 lower_inode->i_ctime.tv_sec,
-+			 lower_inode->i_ctime.tv_nsec);
-+	}
-+}
-+
-+void __show_inode_counts(const struct inode *inode,
-+			const char *file, const char *fxn, int line)
-+{
-+	struct inode *lower_inode;
-+	int bindex;
-+
-+	if (unlikely(!inode)) {
-+		pr_debug("SiC: Null inode\n");
-+		return;
-+	}
-+	for (bindex = sbstart(inode->i_sb); bindex <= sbend(inode->i_sb);
-+	     bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (unlikely(!lower_inode))
-+			continue;
-+		pr_debug("SIC(%lu:%d:%d): lc=%d %s:%s:%d\n",
-+			 inode->i_ino, bindex,
-+			 atomic_read(&(inode)->i_count),
-+			 atomic_read(&(lower_inode)->i_count),
-+			 file, fxn, line);
-+	}
-+}
-diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
-new file mode 100644
-index 0000000..7f0c7f7
---- /dev/null
-+++ b/fs/unionfs/dentry.c
-@@ -0,0 +1,570 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+bool is_negative_lower(const struct dentry *dentry)
-+{
-+	int bindex;
-+	struct dentry *lower_dentry;
-+
-+	BUG_ON(!dentry);
-+	/* cache coherency: check if file was deleted on lower branch */
-+	if (dbstart(dentry) < 0)
-+		return true;
-+	for (bindex = dbstart(dentry); bindex <= dbend(dentry); bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		/* unhashed (i.e., unlinked) lower dentries don't count */
-+		if (lower_dentry && lower_dentry->d_inode &&
-+		    !d_deleted(lower_dentry) &&
-+		    !(lower_dentry->d_flags & DCACHE_NFSFS_RENAMED))
-+			return false;
-+	}
-+	return true;
-+}
-+
-+static inline void __dput_lowers(struct dentry *dentry, int start, int end)
-+{
-+	struct dentry *lower_dentry;
-+	int bindex;
-+
-+	if (start < 0)
-+		return;
-+	for (bindex = start; bindex <= end; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry)
-+			continue;
-+		unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+		dput(lower_dentry);
-+	}
-+}
-+
-+/*
-+ * Revalidate a single dentry.
-+ * Assume that dentry's info node is locked.
-+ * Assume that parent(s) are all valid already, but
-+ * the child may not yet be valid.
-+ * Returns true if valid, false otherwise.
-+ */
-+static bool __unionfs_d_revalidate_one(struct dentry *dentry,
-+				       struct nameidata *nd)
-+{
-+	bool valid = true;	/* default is valid */
-+	struct dentry *lower_dentry;
-+	int bindex, bstart, bend;
-+	int sbgen, dgen;
-+	int positive = 0;
-+	int interpose_flag;
-+	struct nameidata lowernd; /* TODO: be gentler to the stack */
-+
-+	if (nd)
-+		memcpy(&lowernd, nd, sizeof(struct nameidata));
-+	else
-+		memset(&lowernd, 0, sizeof(struct nameidata));
-+
-+	verify_locked(dentry);
-+	verify_locked(dentry->d_parent);
-+
-+	sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
-+	/* if the dentry is unhashed, do NOT revalidate */
-+	if (d_deleted(dentry))
-+		goto out;
-+
-+	BUG_ON(dbstart(dentry) == -1);
-+	if (dentry->d_inode)
-+		positive = 1;
-+	dgen = atomic_read(&UNIONFS_D(dentry)->generation);
-+	/*
-+	 * If we are working on an unconnected dentry, then there is no
-+	 * revalidation to be done, because this file does not exist within
-+	 * the namespace, and Unionfs operates on the namespace, not data.
-+	 */
-+	if (unlikely(sbgen != dgen)) {
-+		struct dentry *result;
-+		int pdgen;
-+
-+		/* The root entry should always be valid */
-+		BUG_ON(IS_ROOT(dentry));
-+
-+		/* We can't work correctly if our parent isn't valid. */
-+		pdgen = atomic_read(&UNIONFS_D(dentry->d_parent)->generation);
-+		BUG_ON(pdgen != sbgen);	/* should never happen here */
-+
-+		/* Free the pointers for our inodes and this dentry. */
-+		bstart = dbstart(dentry);
-+		bend = dbend(dentry);
-+
-+		/*
-+		 * mntput unhashed lower dentries, because those files got
-+		 * deleted or rmdir'ed.
-+		 */
-+		for (bindex = bstart; bindex <= bend; bindex++) {
-+			lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+			if (!lower_dentry)
-+				continue;
-+			if (!d_deleted(lower_dentry) &&
-+			    !(lower_dentry->d_flags & DCACHE_NFSFS_RENAMED))
-+			    continue;
-+			unionfs_mntput(dentry, bindex);
-+		}
-+
-+		__dput_lowers(dentry, bstart, bend);
-+		dbstart(dentry) = dbend(dentry) = -1;
-+
-+		interpose_flag = INTERPOSE_REVAL_NEG;
-+		if (positive) {
-+			interpose_flag = INTERPOSE_REVAL;
-+			iput_lowers_all(dentry->d_inode, true);
-+		}
-+
-+		if (realloc_dentry_private_data(dentry) != 0) {
-+			valid = false;
-+			goto out;
-+		}
-+
-+		result = unionfs_lookup_full(dentry, &lowernd, interpose_flag);
-+		if (result) {
-+			if (IS_ERR(result)) {
-+				valid = false;
-+				goto out;
-+			}
-+			/*
-+			 * current unionfs_lookup_backend() doesn't return
-+			 * a valid dentry
-+			 */
-+			dput(dentry);
-+			dentry = result;
-+		}
-+
-+		if (unlikely(positive && is_negative_lower(dentry))) {
-+			make_bad_inode(dentry->d_inode);
-+			d_drop(dentry);
-+			valid = false;
-+			goto out;
-+		}
-+		goto out;
-+	}
-+
-+	/* The revalidation must occur across all branches */
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+	BUG_ON(bstart == -1);
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry || !lower_dentry->d_op
-+		    || !lower_dentry->d_op->d_revalidate)
-+			continue;
-+		/*
-+		 * Don't pass nameidata to lower file system, because we
-+		 * don't want an arbitrary lower file being opened or
-+		 * returned to us: it may be useless to us because of the
-+		 * fanout nature of unionfs (cf. file/directory open-file
-+		 * invariants).  We will open lower files as and when needed
-+		 * later on.
-+		 */
-+		if (!lower_dentry->d_op->d_revalidate(lower_dentry, NULL))
-+			valid = false;
-+	}
-+
-+	if (!dentry->d_inode ||
-+	    ibstart(dentry->d_inode) < 0 ||
-+	    ibend(dentry->d_inode) < 0) {
-+		valid = false;
-+		goto out;
-+	}
-+
-+	if (valid) {
-+		/*
-+		 * If we get here, and we copy the meta-data from the lower
-+		 * inode to our inode, then it is vital that we have already
-+		 * purged all unionfs-level file data.  We do that in the
-+		 * caller (__unionfs_d_revalidate_chain) by calling
-+		 * purge_inode_data.
-+		 */
-+		unionfs_copy_attr_all(dentry->d_inode,
-+				      unionfs_lower_inode(dentry->d_inode));
-+		fsstack_copy_inode_size(dentry->d_inode,
-+					unionfs_lower_inode(dentry->d_inode));
-+	}
-+
-+out:
-+	if (valid)
-+		atomic_set(&UNIONFS_D(dentry)->generation, sbgen);
-+
-+	return valid;
-+}
-+
-+/*
-+ * Determine if the lower inode objects have changed from below the unionfs
-+ * inode.  Return true if changed, false otherwise.
-+ *
-+ * We check if the mtime or ctime have changed.  However, the inode times
-+ * can be changed by anyone without much protection, including
-+ * asynchronously.  This can sometimes cause unionfs to find that the lower
-+ * file system doesn't change its inode times quick enough, resulting in a
-+ * false positive indication (which is harmless, it just makes unionfs do
-+ * extra work in re-validating the objects).  To minimize the chances of
-+ * these situations, we still consider such small time changes valid, but we
-+ * don't print debugging messages unless the time changes are greater than
-+ * UNIONFS_MIN_CC_TIME (which defaults to 3 seconds, as with NFS's acregmin)
-+ * because significant changes are more likely due to users manually
-+ * touching lower files.
-+ */
-+bool is_newer_lower(const struct dentry *dentry)
-+{
-+	int bindex;
-+	struct inode *inode;
-+	struct inode *lower_inode;
-+
-+	/* ignore if we're called on semi-initialized dentries/inodes */
-+	if (!dentry || !UNIONFS_D(dentry))
-+		return false;
-+	inode = dentry->d_inode;
-+	if (!inode || !UNIONFS_I(inode)->lower_inodes ||
-+	    ibstart(inode) < 0 || ibend(inode) < 0)
-+		return false;
-+
-+	for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (!lower_inode)
-+			continue;
-+
-+		/* check if mtime/ctime have changed */
-+		if (unlikely(timespec_compare(&inode->i_mtime,
-+					      &lower_inode->i_mtime) < 0)) {
-+			if ((lower_inode->i_mtime.tv_sec -
-+			     inode->i_mtime.tv_sec) > UNIONFS_MIN_CC_TIME) {
-+				pr_info("unionfs: new lower inode mtime "
-+					"(bindex=%d, name=%s)\n", bindex,
-+					dentry->d_name.name);
-+				show_dinode_times(dentry);
-+			}
-+			return true;
-+		}
-+		if (unlikely(timespec_compare(&inode->i_ctime,
-+					      &lower_inode->i_ctime) < 0)) {
-+			if ((lower_inode->i_ctime.tv_sec -
-+			     inode->i_ctime.tv_sec) > UNIONFS_MIN_CC_TIME) {
-+				pr_info("unionfs: new lower inode ctime "
-+					"(bindex=%d, name=%s)\n", bindex,
-+					dentry->d_name.name);
-+				show_dinode_times(dentry);
-+			}
-+			return true;
-+		}
-+	}
-+
-+	/*
-+	 * Last check: if this is a positive dentry, but somehow all lower
-+	 * dentries are negative or unhashed, then this dentry needs to be
-+	 * revalidated, because someone probably deleted the objects from
-+	 * the lower branches directly.
-+	 */
-+	if (is_negative_lower(dentry))
-+		return true;
-+
-+	return false;		/* default: lower is not newer */
-+}
-+
-+/*
-+ * Purge and invalidate as many data pages of a unionfs inode.  This is
-+ * called when the lower inode has changed, and we want to force processes
-+ * to re-get the new data.
-+ */
-+static inline void purge_inode_data(struct inode *inode)
-+{
-+	/* remove all non-private mappings */
-+	unmap_mapping_range(inode->i_mapping, 0, 0, 0);
-+	/* invalidate as many pages as possible */
-+	invalidate_mapping_pages(inode->i_mapping, 0, -1);
-+	/*
-+	 * Don't try to truncate_inode_pages here, because this could lead
-+	 * to a deadlock between some of address_space ops and dentry
-+	 * revalidation: the address space op is invoked with a lock on our
-+	 * own page, and truncate_inode_pages will block on locked pages.
-+	 */
-+}
-+
-+/*
-+ * Revalidate a single file/symlink/special dentry.  Assume that info nodes
-+ * of the dentry and its parent are locked.  Assume that parent(s) are all
-+ * valid already, but the child may not yet be valid.  Returns true if
-+ * valid, false otherwise.
-+ */
-+bool __unionfs_d_revalidate_one_locked(struct dentry *dentry,
-+				       struct nameidata *nd,
-+				       bool willwrite)
-+{
-+	bool valid = false;	/* default is invalid */
-+	int sbgen, dgen, bindex;
-+
-+	verify_locked(dentry);
-+	verify_locked(dentry->d_parent);
-+
-+	sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
-+	dgen = atomic_read(&UNIONFS_D(dentry)->generation);
-+
-+	if (unlikely(is_newer_lower(dentry))) {
-+		/* root dentry special case as aforementioned */
-+		if (IS_ROOT(dentry)) {
-+			unionfs_copy_attr_times(dentry->d_inode);
-+		} else {
-+			/*
-+			 * reset generation number to zero, guaranteed to be
-+			 * "old"
-+			 */
-+			dgen = 0;
-+			atomic_set(&UNIONFS_D(dentry)->generation, dgen);
-+		}
-+		if (!willwrite)
-+			purge_inode_data(dentry->d_inode);
-+	}
-+	valid = __unionfs_d_revalidate_one(dentry, nd);
-+
-+	/*
-+	 * If __unionfs_d_revalidate_one() succeeded above, then it will
-+	 * have incremented the refcnt of the mnt's, but also the branch
-+	 * indices of the dentry will have been updated (to take into
-+	 * account any branch insertions/deletion.  So the current
-+	 * dbstart/dbend match the current, and new, indices of the mnts
-+	 * which __unionfs_d_revalidate_one has incremented.  Note: the "if"
-+	 * test below does not depend on whether chain_len was 0 or greater.
-+	 */
-+	if (!valid || sbgen == dgen)
-+		goto out;
-+	for (bindex = dbstart(dentry); bindex <= dbend(dentry); bindex++)
-+		unionfs_mntput(dentry, bindex);
-+out:
-+	return valid;
-+}
-+
-+/*
-+ * Revalidate a parent chain of dentries, then the actual node.
-+ * Assumes that dentry is locked, but will lock all parents if/when needed.
-+ *
-+ * If 'willwrite' is true, and the lower inode times are not in sync, then
-+ * *don't* purge_inode_data, as it could deadlock if ->write calls us and we
-+ * try to truncate a locked page.  Besides, if unionfs is about to write
-+ * data to a file, then there's the data unionfs is about to write is more
-+ * authoritative than what's below, therefore we can safely overwrite the
-+ * lower inode times and data.
-+ */
-+bool __unionfs_d_revalidate_chain(struct dentry *dentry, struct nameidata *nd,
-+				  bool willwrite)
-+{
-+	bool valid = false;	/* default is invalid */
-+	struct dentry **chain = NULL; /* chain of dentries to reval */
-+	int chain_len = 0;
-+	struct dentry *dtmp;
-+	int sbgen, dgen, i;
-+	int saved_bstart, saved_bend, bindex;
-+
-+	/* find length of chain needed to revalidate */
-+	/* XXX: should I grab some global (dcache?) lock? */
-+	chain_len = 0;
-+	sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
-+	dtmp = dentry->d_parent;
-+	verify_locked(dentry);
-+	if (dentry != dtmp)
-+		unionfs_lock_dentry(dtmp, UNIONFS_DMUTEX_REVAL_PARENT);
-+	dgen = atomic_read(&UNIONFS_D(dtmp)->generation);
-+	/* XXX: should we check if is_newer_lower all the way up? */
-+	if (unlikely(is_newer_lower(dtmp))) {
-+		/*
-+		 * Special case: the root dentry's generation number must
-+		 * always be valid, but its lower inode times don't have to
-+		 * be, so sync up the times only.
-+		 */
-+		if (IS_ROOT(dtmp)) {
-+			unionfs_copy_attr_times(dtmp->d_inode);
-+		} else {
-+			/*
-+			 * reset generation number to zero, guaranteed to be
-+			 * "old"
-+			 */
-+			dgen = 0;
-+			atomic_set(&UNIONFS_D(dtmp)->generation, dgen);
-+		}
-+		purge_inode_data(dtmp->d_inode);
-+	}
-+	if (dentry != dtmp)
-+		unionfs_unlock_dentry(dtmp);
-+	while (sbgen != dgen) {
-+		/* The root entry should always be valid */
-+		BUG_ON(IS_ROOT(dtmp));
-+		chain_len++;
-+		dtmp = dtmp->d_parent;
-+		dgen = atomic_read(&UNIONFS_D(dtmp)->generation);
-+	}
-+	if (chain_len == 0)
-+		goto out_this;	/* shortcut if parents are OK */
-+
-+	/*
-+	 * Allocate array of dentries to reval.  We could use linked lists,
-+	 * but the number of entries we need to alloc here is often small,
-+	 * and short lived, so locality will be better.
-+	 */
-+	chain = kzalloc(chain_len * sizeof(struct dentry *), GFP_KERNEL);
-+	if (unlikely(!chain)) {
-+		printk(KERN_CRIT "unionfs: no more memory in %s\n",
-+		       __func__);
-+		goto out;
-+	}
-+
-+	/* grab all dentries in chain, in child to parent order */
-+	dtmp = dentry;
-+	for (i = chain_len-1; i >= 0; i--)
-+		dtmp = chain[i] = dget_parent(dtmp);
-+
-+	/*
-+	 * call __unionfs_d_revalidate_one() on each dentry, but in parent
-+	 * to child order.
-+	 */
-+	for (i = 0; i < chain_len; i++) {
-+		unionfs_lock_dentry(chain[i], UNIONFS_DMUTEX_REVAL_CHILD);
-+		if (chain[i] != chain[i]->d_parent)
-+			unionfs_lock_dentry(chain[i]->d_parent,
-+					    UNIONFS_DMUTEX_REVAL_PARENT);
-+		saved_bstart = dbstart(chain[i]);
-+		saved_bend = dbend(chain[i]);
-+		sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
-+		dgen = atomic_read(&UNIONFS_D(chain[i])->generation);
-+
-+		valid = __unionfs_d_revalidate_one(chain[i], nd);
-+		/* XXX: is this the correct mntput condition?! */
-+		if (valid && chain_len > 0 &&
-+		    sbgen != dgen && chain[i]->d_inode &&
-+		    S_ISDIR(chain[i]->d_inode->i_mode)) {
-+			for (bindex = saved_bstart; bindex <= saved_bend;
-+			     bindex++)
-+				unionfs_mntput(chain[i], bindex);
-+		}
-+		if (chain[i] != chain[i]->d_parent)
-+			unionfs_unlock_dentry(chain[i]->d_parent);
-+		unionfs_unlock_dentry(chain[i]);
-+
-+		if (unlikely(!valid))
-+			goto out_free;
-+	}
-+
-+
-+out_this:
-+	/* finally, lock this dentry and revalidate it */
-+	verify_locked(dentry);	/* verify child is locked */
-+	if (dentry != dentry->d_parent)
-+		unionfs_lock_dentry(dentry->d_parent,
-+				    UNIONFS_DMUTEX_REVAL_PARENT);
-+	valid = __unionfs_d_revalidate_one_locked(dentry, nd, willwrite);
-+	if (dentry != dentry->d_parent)
-+		unionfs_unlock_dentry(dentry->d_parent);
-+
-+out_free:
-+	/* unlock/dput all dentries in chain and return status */
-+	if (chain_len > 0) {
-+		for (i = 0; i < chain_len; i++)
-+			dput(chain[i]);
-+		kfree(chain);
-+	}
-+out:
-+	return valid;
-+}
-+
-+static int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
-+{
-+	int err;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	err = __unionfs_d_revalidate_chain(dentry, nd, false);
-+	if (likely(err > 0)) { /* true==1: dentry is valid */
-+		unionfs_postcopyup_setmnt(dentry);
-+		unionfs_check_dentry(dentry);
-+		unionfs_check_nd(nd);
-+	}
-+	unionfs_unlock_dentry(dentry);
-+
-+	unionfs_read_unlock(dentry->d_sb);
-+
-+	return err;
-+}
-+
-+static void unionfs_d_release(struct dentry *dentry)
-+{
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	if (unlikely(!UNIONFS_D(dentry)))
-+		goto out;	/* skip if no lower branches */
-+	/* must lock our branch configuration here */
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	unionfs_check_dentry(dentry);
-+	/* this could be a negative dentry, so check first */
-+	if (dbstart(dentry) < 0) {
-+		unionfs_unlock_dentry(dentry);
-+		goto out;	/* due to a (normal) failed lookup */
-+	}
-+
-+	/* Release all the lower dentries */
-+	path_put_lowers_all(dentry, true);
-+
-+	unionfs_unlock_dentry(dentry);
-+
-+out:
-+	free_dentry_private_data(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return;
-+}
-+
-+/*
-+ * Called when we're removing the last reference to our dentry.  So we
-+ * should drop all lower references too.
-+ */
-+static void unionfs_d_iput(struct dentry *dentry, struct inode *inode)
-+{
-+	int rc;
-+
-+	BUG_ON(!dentry);
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (!UNIONFS_D(dentry) || dbstart(dentry) < 0)
-+		goto drop_lower_inodes;
-+	path_put_lowers_all(dentry, false);
-+
-+drop_lower_inodes:
-+	rc = atomic_read(&inode->i_count);
-+	if (rc == 1 && inode->i_nlink == 1 && ibstart(inode) >= 0) {
-+		/* see Documentation/filesystems/unionfs/issues.txt */
-+		lockdep_off();
-+		iput(unionfs_lower_inode(inode));
-+		lockdep_on();
-+		unionfs_set_lower_inode(inode, NULL);
-+		/* XXX: may need to set start/end to -1? */
-+	}
-+
-+	iput(inode);
-+
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+}
-+
-+struct dentry_operations unionfs_dops = {
-+	.d_revalidate	= unionfs_d_revalidate,
-+	.d_release	= unionfs_d_release,
-+	.d_iput		= unionfs_d_iput,
-+};
-diff --git a/fs/unionfs/dirfops.c b/fs/unionfs/dirfops.c
-new file mode 100644
-index 0000000..14ca7d3
---- /dev/null
-+++ b/fs/unionfs/dirfops.c
-@@ -0,0 +1,292 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/* Make sure our rdstate is playing by the rules. */
-+static void verify_rdstate_offset(struct unionfs_dir_state *rdstate)
-+{
-+	BUG_ON(rdstate->offset >= DIREOF);
-+	BUG_ON(rdstate->cookie >= MAXRDCOOKIE);
-+}
-+
-+struct unionfs_getdents_callback {
-+	struct unionfs_dir_state *rdstate;
-+	void *dirent;
-+	int entries_written;
-+	int filldir_called;
-+	int filldir_error;
-+	filldir_t filldir;
-+	struct super_block *sb;
-+};
-+
-+/* based on generic filldir in fs/readir.c */
-+static int unionfs_filldir(void *dirent, const char *oname, int namelen,
-+			   loff_t offset, u64 ino, unsigned int d_type)
-+{
-+	struct unionfs_getdents_callback *buf = dirent;
-+	struct filldir_node *found = NULL;
-+	int err = 0;
-+	int is_whiteout;
-+	char *name = (char *) oname;
-+
-+	buf->filldir_called++;
-+
-+	is_whiteout = is_whiteout_name(&name, &namelen);
-+
-+	found = find_filldir_node(buf->rdstate, name, namelen, is_whiteout);
-+
-+	if (found) {
-+		/*
-+		 * If we had non-whiteout entry in dir cache, then mark it
-+		 * as a whiteout and but leave it in the dir cache.
-+		 */
-+		if (is_whiteout && !found->whiteout)
-+			found->whiteout = is_whiteout;
-+		goto out;
-+	}
-+
-+	/* if 'name' isn't a whiteout, filldir it. */
-+	if (!is_whiteout) {
-+		off_t pos = rdstate2offset(buf->rdstate);
-+		u64 unionfs_ino = ino;
-+
-+		err = buf->filldir(buf->dirent, name, namelen, pos,
-+				   unionfs_ino, d_type);
-+		buf->rdstate->offset++;
-+		verify_rdstate_offset(buf->rdstate);
-+	}
-+	/*
-+	 * If we did fill it, stuff it in our hash, otherwise return an
-+	 * error.
-+	 */
-+	if (err) {
-+		buf->filldir_error = err;
-+		goto out;
-+	}
-+	buf->entries_written++;
-+	err = add_filldir_node(buf->rdstate, name, namelen,
-+			       buf->rdstate->bindex, is_whiteout);
-+	if (err)
-+		buf->filldir_error = err;
-+
-+out:
-+	return err;
-+}
-+
-+static int unionfs_readdir(struct file *file, void *dirent, filldir_t filldir)
-+{
-+	int err = 0;
-+	struct file *lower_file = NULL;
-+	struct dentry *dentry = file->f_path.dentry;
-+	struct inode *inode = NULL;
-+	struct unionfs_getdents_callback buf;
-+	struct unionfs_dir_state *uds;
-+	int bend;
-+	loff_t offset;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	err = unionfs_file_revalidate(file, false);
-+	if (unlikely(err))
-+		goto out;
-+
-+	inode = dentry->d_inode;
-+
-+	uds = UNIONFS_F(file)->rdstate;
-+	if (!uds) {
-+		if (file->f_pos == DIREOF) {
-+			goto out;
-+		} else if (file->f_pos > 0) {
-+			uds = find_rdstate(inode, file->f_pos);
-+			if (unlikely(!uds)) {
-+				err = -ESTALE;
-+				goto out;
-+			}
-+			UNIONFS_F(file)->rdstate = uds;
-+		} else {
-+			init_rdstate(file);
-+			uds = UNIONFS_F(file)->rdstate;
-+		}
-+	}
-+	bend = fbend(file);
-+
-+	while (uds->bindex <= bend) {
-+		lower_file = unionfs_lower_file_idx(file, uds->bindex);
-+		if (!lower_file) {
-+			uds->bindex++;
-+			uds->dirpos = 0;
-+			continue;
-+		}
-+
-+		/* prepare callback buffer */
-+		buf.filldir_called = 0;
-+		buf.filldir_error = 0;
-+		buf.entries_written = 0;
-+		buf.dirent = dirent;
-+		buf.filldir = filldir;
-+		buf.rdstate = uds;
-+		buf.sb = inode->i_sb;
-+
-+		/* Read starting from where we last left off. */
-+		offset = vfs_llseek(lower_file, uds->dirpos, SEEK_SET);
-+		if (offset < 0) {
-+			err = offset;
-+			goto out;
-+		}
-+		err = vfs_readdir(lower_file, unionfs_filldir, &buf);
-+
-+		/* Save the position for when we continue. */
-+		offset = vfs_llseek(lower_file, 0, SEEK_CUR);
-+		if (offset < 0) {
-+			err = offset;
-+			goto out;
-+		}
-+		uds->dirpos = offset;
-+
-+		/* Copy the atime. */
-+		fsstack_copy_attr_atime(inode,
-+					lower_file->f_path.dentry->d_inode);
-+
-+		if (err < 0)
-+			goto out;
-+
-+		if (buf.filldir_error)
-+			break;
-+
-+		if (!buf.entries_written) {
-+			uds->bindex++;
-+			uds->dirpos = 0;
-+		}
-+	}
-+
-+	if (!buf.filldir_error && uds->bindex >= bend) {
-+		/* Save the number of hash entries for next time. */
-+		UNIONFS_I(inode)->hashsize = uds->hashentries;
-+		free_rdstate(uds);
-+		UNIONFS_F(file)->rdstate = NULL;
-+		file->f_pos = DIREOF;
-+	} else {
-+		file->f_pos = rdstate2offset(uds);
-+	}
-+
-+out:
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+/*
-+ * This is not meant to be a generic repositioning function.  If you do
-+ * things that aren't supported, then we return EINVAL.
-+ *
-+ * What is allowed:
-+ *  (1) seeking to the same position that you are currently at
-+ *	This really has no effect, but returns where you are.
-+ *  (2) seeking to the beginning of the file
-+ *	This throws out all state, and lets you begin again.
-+ */
-+static loff_t unionfs_dir_llseek(struct file *file, loff_t offset, int origin)
-+{
-+	struct unionfs_dir_state *rdstate;
-+	struct dentry *dentry = file->f_path.dentry;
-+	loff_t err;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	err = unionfs_file_revalidate(file, false);
-+	if (unlikely(err))
-+		goto out;
-+
-+	rdstate = UNIONFS_F(file)->rdstate;
-+
-+	/*
-+	 * we let users seek to their current position, but not anywhere
-+	 * else.
-+	 */
-+	if (!offset) {
-+		switch (origin) {
-+		case SEEK_SET:
-+			if (rdstate) {
-+				free_rdstate(rdstate);
-+				UNIONFS_F(file)->rdstate = NULL;
-+			}
-+			init_rdstate(file);
-+			err = 0;
-+			break;
-+		case SEEK_CUR:
-+			err = file->f_pos;
-+			break;
-+		case SEEK_END:
-+			/* Unsupported, because we would break everything.  */
-+			err = -EINVAL;
-+			break;
-+		}
-+	} else {
-+		switch (origin) {
-+		case SEEK_SET:
-+			if (rdstate) {
-+				if (offset == rdstate2offset(rdstate))
-+					err = offset;
-+				else if (file->f_pos == DIREOF)
-+					err = DIREOF;
-+				else
-+					err = -EINVAL;
-+			} else {
-+				struct inode *inode;
-+				inode = dentry->d_inode;
-+				rdstate = find_rdstate(inode, offset);
-+				if (rdstate) {
-+					UNIONFS_F(file)->rdstate = rdstate;
-+					err = rdstate->offset;
-+				} else {
-+					err = -EINVAL;
-+				}
-+			}
-+			break;
-+		case SEEK_CUR:
-+		case SEEK_END:
-+			/* Unsupported, because we would break everything.  */
-+			err = -EINVAL;
-+			break;
-+		}
-+	}
-+
-+out:
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+/*
-+ * Trimmed directory options, we shouldn't pass everything down since
-+ * we don't want to operate on partial directories.
-+ */
-+struct file_operations unionfs_dir_fops = {
-+	.llseek		= unionfs_dir_llseek,
-+	.read		= generic_read_dir,
-+	.readdir	= unionfs_readdir,
-+	.unlocked_ioctl	= unionfs_ioctl,
-+	.open		= unionfs_open,
-+	.release	= unionfs_file_release,
-+	.flush		= unionfs_flush,
-+	.fsync		= unionfs_fsync,
-+	.fasync		= unionfs_fasync,
-+};
-diff --git a/fs/unionfs/dirhelper.c b/fs/unionfs/dirhelper.c
-new file mode 100644
-index 0000000..d936f03
---- /dev/null
-+++ b/fs/unionfs/dirhelper.c
-@@ -0,0 +1,157 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+#define RD_NONE 0
-+#define RD_CHECK_EMPTY 1
-+/* The callback structure for check_empty. */
-+struct unionfs_rdutil_callback {
-+	int err;
-+	int filldir_called;
-+	struct unionfs_dir_state *rdstate;
-+	int mode;
-+};
-+
-+/* This filldir function makes sure only whiteouts exist within a directory. */
-+static int readdir_util_callback(void *dirent, const char *oname, int namelen,
-+				 loff_t offset, u64 ino, unsigned int d_type)
-+{
-+	int err = 0;
-+	struct unionfs_rdutil_callback *buf = dirent;
-+	int is_whiteout;
-+	struct filldir_node *found;
-+	char *name = (char *) oname;
-+
-+	buf->filldir_called = 1;
-+
-+	if (name[0] == '.' && (namelen == 1 ||
-+			       (name[1] == '.' && namelen == 2)))
-+		goto out;
-+
-+	is_whiteout = is_whiteout_name(&name, &namelen);
-+
-+	found = find_filldir_node(buf->rdstate, name, namelen, is_whiteout);
-+	/* If it was found in the table there was a previous whiteout. */
-+	if (found)
-+		goto out;
-+
-+	/*
-+	 * if it wasn't found and isn't a whiteout, the directory isn't
-+	 * empty.
-+	 */
-+	err = -ENOTEMPTY;
-+	if ((buf->mode == RD_CHECK_EMPTY) && !is_whiteout)
-+		goto out;
-+
-+	err = add_filldir_node(buf->rdstate, name, namelen,
-+			       buf->rdstate->bindex, is_whiteout);
-+
-+out:
-+	buf->err = err;
-+	return err;
-+}
-+
-+/* Is a directory logically empty? */
-+int check_empty(struct dentry *dentry, struct unionfs_dir_state **namelist)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry = NULL;
-+	struct vfsmount *mnt;
-+	struct super_block *sb;
-+	struct file *lower_file;
-+	struct unionfs_rdutil_callback *buf = NULL;
-+	int bindex, bstart, bend, bopaque;
-+
-+	sb = dentry->d_sb;
-+
-+
-+	BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));
-+
-+	err = unionfs_partial_lookup(dentry);
-+	if (err)
-+		goto out;
-+
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+	bopaque = dbopaque(dentry);
-+	if (0 <= bopaque && bopaque < bend)
-+		bend = bopaque;
-+
-+	buf = kmalloc(sizeof(struct unionfs_rdutil_callback), GFP_KERNEL);
-+	if (unlikely(!buf)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+	buf->err = 0;
-+	buf->mode = RD_CHECK_EMPTY;
-+	buf->rdstate = alloc_rdstate(dentry->d_inode, bstart);
-+	if (unlikely(!buf->rdstate)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+
-+	/* Process the lower directories with rdutil_callback as a filldir. */
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry)
-+			continue;
-+		if (!lower_dentry->d_inode)
-+			continue;
-+		if (!S_ISDIR(lower_dentry->d_inode->i_mode))
-+			continue;
-+
-+		dget(lower_dentry);
-+		mnt = unionfs_mntget(dentry, bindex);
-+		branchget(sb, bindex);
-+		lower_file = dentry_open(lower_dentry, mnt, O_RDONLY);
-+		if (IS_ERR(lower_file)) {
-+			err = PTR_ERR(lower_file);
-+			branchput(sb, bindex);
-+			goto out;
-+		}
-+
-+		do {
-+			buf->filldir_called = 0;
-+			buf->rdstate->bindex = bindex;
-+			err = vfs_readdir(lower_file,
-+					  readdir_util_callback, buf);
-+			if (buf->err)
-+				err = buf->err;
-+		} while ((err >= 0) && buf->filldir_called);
-+
-+		/* fput calls dput for lower_dentry */
-+		fput(lower_file);
-+		branchput(sb, bindex);
-+
-+		if (err < 0)
-+			goto out;
-+	}
-+
-+out:
-+	if (buf) {
-+		if (namelist && !err)
-+			*namelist = buf->rdstate;
-+		else if (buf->rdstate)
-+			free_rdstate(buf->rdstate);
-+		kfree(buf);
-+	}
-+
-+
-+	return err;
-+}
-diff --git a/fs/unionfs/fanout.h b/fs/unionfs/fanout.h
-new file mode 100644
-index 0000000..4f264de
---- /dev/null
-+++ b/fs/unionfs/fanout.h
-@@ -0,0 +1,384 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#ifndef _FANOUT_H_
-+#define _FANOUT_H_
-+
-+/*
-+ * Inode to private data
-+ *
-+ * Since we use containers and the struct inode is _inside_ the
-+ * unionfs_inode_info structure, UNIONFS_I will always (given a non-NULL
-+ * inode pointer), return a valid non-NULL pointer.
-+ */
-+static inline struct unionfs_inode_info *UNIONFS_I(const struct inode *inode)
-+{
-+	return container_of(inode, struct unionfs_inode_info, vfs_inode);
-+}
-+
-+#define ibstart(ino) (UNIONFS_I(ino)->bstart)
-+#define ibend(ino) (UNIONFS_I(ino)->bend)
-+
-+/* Dentry to private data */
-+#define UNIONFS_D(dent) ((struct unionfs_dentry_info *)(dent)->d_fsdata)
-+#define dbstart(dent) (UNIONFS_D(dent)->bstart)
-+#define dbend(dent) (UNIONFS_D(dent)->bend)
-+#define dbopaque(dent) (UNIONFS_D(dent)->bopaque)
-+
-+/* Superblock to private data */
-+#define UNIONFS_SB(super) ((struct unionfs_sb_info *)(super)->s_fs_info)
-+#define sbstart(sb) 0
-+#define sbend(sb) (UNIONFS_SB(sb)->bend)
-+#define sbmax(sb) (UNIONFS_SB(sb)->bend + 1)
-+#define sbhbid(sb) (UNIONFS_SB(sb)->high_branch_id)
-+
-+/* File to private Data */
-+#define UNIONFS_F(file) ((struct unionfs_file_info *)((file)->private_data))
-+#define fbstart(file) (UNIONFS_F(file)->bstart)
-+#define fbend(file) (UNIONFS_F(file)->bend)
-+
-+/* macros to manipulate branch IDs in stored in our superblock */
-+static inline int branch_id(struct super_block *sb, int index)
-+{
-+	BUG_ON(!sb || index < 0);
-+	return UNIONFS_SB(sb)->data[index].branch_id;
-+}
-+
-+static inline void set_branch_id(struct super_block *sb, int index, int val)
-+{
-+	BUG_ON(!sb || index < 0);
-+	UNIONFS_SB(sb)->data[index].branch_id = val;
-+}
-+
-+static inline void new_branch_id(struct super_block *sb, int index)
-+{
-+	BUG_ON(!sb || index < 0);
-+	set_branch_id(sb, index, ++UNIONFS_SB(sb)->high_branch_id);
-+}
-+
-+/*
-+ * Find new index of matching branch with an existing superblock of a known
-+ * (possibly old) id.  This is needed because branches could have been
-+ * added/deleted causing the branches of any open files to shift.
-+ *
-+ * @sb: the new superblock which may have new/different branch IDs
-+ * @id: the old/existing id we're looking for
-+ * Returns index of newly found branch (0 or greater), -1 otherwise.
-+ */
-+static inline int branch_id_to_idx(struct super_block *sb, int id)
-+{
-+	int i;
-+	for (i = 0; i < sbmax(sb); i++) {
-+		if (branch_id(sb, i) == id)
-+			return i;
-+	}
-+	/* in the non-ODF code, this should really never happen */
-+	printk(KERN_WARNING "unionfs: cannot find branch with id %d\n", id);
-+	return -1;
-+}
-+
-+/* File to lower file. */
-+static inline struct file *unionfs_lower_file(const struct file *f)
-+{
-+	BUG_ON(!f);
-+	return UNIONFS_F(f)->lower_files[fbstart(f)];
-+}
-+
-+static inline struct file *unionfs_lower_file_idx(const struct file *f,
-+						  int index)
-+{
-+	BUG_ON(!f || index < 0);
-+	return UNIONFS_F(f)->lower_files[index];
-+}
-+
-+static inline void unionfs_set_lower_file_idx(struct file *f, int index,
-+					      struct file *val)
-+{
-+	BUG_ON(!f || index < 0);
-+	UNIONFS_F(f)->lower_files[index] = val;
-+	/* save branch ID (may be redundant?) */
-+	UNIONFS_F(f)->saved_branch_ids[index] =
-+		branch_id((f)->f_path.dentry->d_sb, index);
-+}
-+
-+static inline void unionfs_set_lower_file(struct file *f, struct file *val)
-+{
-+	BUG_ON(!f);
-+	unionfs_set_lower_file_idx((f), fbstart(f), (val));
-+}
-+
-+/* Inode to lower inode. */
-+static inline struct inode *unionfs_lower_inode(const struct inode *i)
-+{
-+	BUG_ON(!i);
-+	return UNIONFS_I(i)->lower_inodes[ibstart(i)];
-+}
-+
-+static inline struct inode *unionfs_lower_inode_idx(const struct inode *i,
-+						    int index)
-+{
-+	BUG_ON(!i || index < 0);
-+	return UNIONFS_I(i)->lower_inodes[index];
-+}
-+
-+static inline void unionfs_set_lower_inode_idx(struct inode *i, int index,
-+					       struct inode *val)
-+{
-+	BUG_ON(!i || index < 0);
-+	UNIONFS_I(i)->lower_inodes[index] = val;
-+}
-+
-+static inline void unionfs_set_lower_inode(struct inode *i, struct inode *val)
-+{
-+	BUG_ON(!i);
-+	UNIONFS_I(i)->lower_inodes[ibstart(i)] = val;
-+}
-+
-+/* Superblock to lower superblock. */
-+static inline struct super_block *unionfs_lower_super(
-+					const struct super_block *sb)
-+{
-+	BUG_ON(!sb);
-+	return UNIONFS_SB(sb)->data[sbstart(sb)].sb;
-+}
-+
-+static inline struct super_block *unionfs_lower_super_idx(
-+					const struct super_block *sb,
-+					int index)
-+{
-+	BUG_ON(!sb || index < 0);
-+	return UNIONFS_SB(sb)->data[index].sb;
-+}
-+
-+static inline void unionfs_set_lower_super_idx(struct super_block *sb,
-+					       int index,
-+					       struct super_block *val)
-+{
-+	BUG_ON(!sb || index < 0);
-+	UNIONFS_SB(sb)->data[index].sb = val;
-+}
-+
-+static inline void unionfs_set_lower_super(struct super_block *sb,
-+					   struct super_block *val)
-+{
-+	BUG_ON(!sb);
-+	UNIONFS_SB(sb)->data[sbstart(sb)].sb = val;
-+}
-+
-+/* Branch count macros. */
-+static inline int branch_count(const struct super_block *sb, int index)
-+{
-+	BUG_ON(!sb || index < 0);
-+	return atomic_read(&UNIONFS_SB(sb)->data[index].open_files);
-+}
-+
-+static inline void set_branch_count(struct super_block *sb, int index, int val)
-+{
-+	BUG_ON(!sb || index < 0);
-+	atomic_set(&UNIONFS_SB(sb)->data[index].open_files, val);
-+}
-+
-+static inline void branchget(struct super_block *sb, int index)
-+{
-+	BUG_ON(!sb || index < 0);
-+	atomic_inc(&UNIONFS_SB(sb)->data[index].open_files);
-+}
-+
-+static inline void branchput(struct super_block *sb, int index)
-+{
-+	BUG_ON(!sb || index < 0);
-+	atomic_dec(&UNIONFS_SB(sb)->data[index].open_files);
-+}
-+
-+/* Dentry macros */
-+static inline void unionfs_set_lower_dentry_idx(struct dentry *dent, int index,
-+						struct dentry *val)
-+{
-+	BUG_ON(!dent || index < 0);
-+	UNIONFS_D(dent)->lower_paths[index].dentry = val;
-+}
-+
-+static inline struct dentry *unionfs_lower_dentry_idx(
-+				const struct dentry *dent,
-+				int index)
-+{
-+	BUG_ON(!dent || index < 0);
-+	return UNIONFS_D(dent)->lower_paths[index].dentry;
-+}
-+
-+static inline struct dentry *unionfs_lower_dentry(const struct dentry *dent)
-+{
-+	BUG_ON(!dent);
-+	return unionfs_lower_dentry_idx(dent, dbstart(dent));
-+}
-+
-+static inline void unionfs_set_lower_mnt_idx(struct dentry *dent, int index,
-+					     struct vfsmount *mnt)
-+{
-+	BUG_ON(!dent || index < 0);
-+	UNIONFS_D(dent)->lower_paths[index].mnt = mnt;
-+}
-+
-+static inline struct vfsmount *unionfs_lower_mnt_idx(
-+					const struct dentry *dent,
-+					int index)
-+{
-+	BUG_ON(!dent || index < 0);
-+	return UNIONFS_D(dent)->lower_paths[index].mnt;
-+}
-+
-+static inline struct vfsmount *unionfs_lower_mnt(const struct dentry *dent)
-+{
-+	BUG_ON(!dent);
-+	return unionfs_lower_mnt_idx(dent, dbstart(dent));
-+}
-+
-+/* Macros for locking a dentry. */
-+enum unionfs_dentry_lock_class {
-+	UNIONFS_DMUTEX_NORMAL,
-+	UNIONFS_DMUTEX_ROOT,
-+	UNIONFS_DMUTEX_PARENT,
-+	UNIONFS_DMUTEX_CHILD,
-+	UNIONFS_DMUTEX_WHITEOUT,
-+	UNIONFS_DMUTEX_REVAL_PARENT, /* for file/dentry revalidate */
-+	UNIONFS_DMUTEX_REVAL_CHILD,   /* for file/dentry revalidate */
-+};
-+
-+static inline void unionfs_lock_dentry(struct dentry *d,
-+				       unsigned int subclass)
-+{
-+	BUG_ON(!d);
-+	mutex_lock_nested(&UNIONFS_D(d)->lock, subclass);
-+}
-+
-+static inline void unionfs_unlock_dentry(struct dentry *d)
-+{
-+	BUG_ON(!d);
-+	mutex_unlock(&UNIONFS_D(d)->lock);
-+}
-+
-+static inline void verify_locked(struct dentry *d)
-+{
-+	BUG_ON(!d);
-+	BUG_ON(!mutex_is_locked(&UNIONFS_D(d)->lock));
-+}
-+
-+/* macros to put lower objects */
-+
-+/*
-+ * iput lower inodes of an unionfs dentry, from bstart to bend.  If
-+ * @free_lower is true, then also kfree the memory used to hold the lower
-+ * object pointers.
-+ */
-+static inline void iput_lowers(struct inode *inode,
-+			       int bstart, int bend, bool free_lower)
-+{
-+	struct inode *lower_inode;
-+	int bindex;
-+
-+	BUG_ON(!inode);
-+	BUG_ON(!UNIONFS_I(inode));
-+	BUG_ON(bstart < 0);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (lower_inode) {
-+			unionfs_set_lower_inode_idx(inode, bindex, NULL);
-+			/* see Documentation/filesystems/unionfs/issues.txt */
-+			lockdep_off();
-+			iput(lower_inode);
-+			lockdep_on();
-+		}
-+	}
-+
-+	if (free_lower) {
-+		kfree(UNIONFS_I(inode)->lower_inodes);
-+		UNIONFS_I(inode)->lower_inodes = NULL;
-+	}
-+}
-+
-+/* iput all lower inodes, and reset start/end branch indices to -1 */
-+static inline void iput_lowers_all(struct inode *inode, bool free_lower)
-+{
-+	int bstart, bend;
-+
-+	BUG_ON(!inode);
-+	BUG_ON(!UNIONFS_I(inode));
-+	bstart = ibstart(inode);
-+	bend = ibend(inode);
-+	BUG_ON(bstart < 0);
-+
-+	iput_lowers(inode, bstart, bend, free_lower);
-+	ibstart(inode) = ibend(inode) = -1;
-+}
-+
-+/*
-+ * dput/mntput all lower dentries and vfsmounts of an unionfs dentry, from
-+ * bstart to bend.  If @free_lower is true, then also kfree the memory used
-+ * to hold the lower object pointers.
-+ *
-+ * XXX: implement using path_put VFS macros
-+ */
-+static inline void path_put_lowers(struct dentry *dentry,
-+				   int bstart, int bend, bool free_lower)
-+{
-+	struct dentry *lower_dentry;
-+	struct vfsmount *lower_mnt;
-+	int bindex;
-+
-+	BUG_ON(!dentry);
-+	BUG_ON(!UNIONFS_D(dentry));
-+	BUG_ON(bstart < 0);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (lower_dentry) {
-+			unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+			dput(lower_dentry);
-+		}
-+		lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+		if (lower_mnt) {
-+			unionfs_set_lower_mnt_idx(dentry, bindex, NULL);
-+			mntput(lower_mnt);
-+		}
-+	}
-+
-+	if (free_lower) {
-+		kfree(UNIONFS_D(dentry)->lower_paths);
-+		UNIONFS_D(dentry)->lower_paths = NULL;
-+	}
-+}
-+
-+/*
-+ * dput/mntput all lower dentries and vfsmounts, and reset start/end branch
-+ * indices to -1.
-+ */
-+static inline void path_put_lowers_all(struct dentry *dentry, bool free_lower)
-+{
-+	int bstart, bend;
-+
-+	BUG_ON(!dentry);
-+	BUG_ON(!UNIONFS_D(dentry));
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+	BUG_ON(bstart < 0);
-+
-+	path_put_lowers(dentry, bstart, bend, free_lower);
-+	dbstart(dentry) = dbend(dentry) = -1;
-+}
-+
-+#endif	/* not _FANOUT_H */
-diff --git a/fs/unionfs/file.c b/fs/unionfs/file.c
-new file mode 100644
-index 0000000..965d071
---- /dev/null
-+++ b/fs/unionfs/file.c
-@@ -0,0 +1,341 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+static ssize_t unionfs_read(struct file *file, char __user *buf,
-+			    size_t count, loff_t *ppos)
-+{
-+	int err;
-+	struct file *lower_file;
-+	struct dentry *dentry = file->f_path.dentry;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	err = unionfs_file_revalidate(file, false);
-+	if (unlikely(err))
-+		goto out;
-+
-+	lower_file = unionfs_lower_file(file);
-+	err = vfs_read(lower_file, buf, count, ppos);
-+	/* update our inode atime upon a successful lower read */
-+	if (err >= 0) {
-+		fsstack_copy_attr_atime(dentry->d_inode,
-+					lower_file->f_path.dentry->d_inode);
-+		unionfs_check_file(file);
-+	}
-+
-+out:
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+static ssize_t unionfs_write(struct file *file, const char __user *buf,
-+			     size_t count, loff_t *ppos)
-+{
-+	int err = 0;
-+	struct file *lower_file;
-+	struct dentry *dentry = file->f_path.dentry;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	if (dentry != dentry->d_parent)
-+		unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
-+	err = unionfs_file_revalidate_locked(file, true);
-+	if (unlikely(err))
-+		goto out;
-+
-+	lower_file = unionfs_lower_file(file);
-+	err = vfs_write(lower_file, buf, count, ppos);
-+	/* update our inode times+sizes upon a successful lower write */
-+	if (err >= 0) {
-+		fsstack_copy_inode_size(dentry->d_inode,
-+					lower_file->f_path.dentry->d_inode);
-+		fsstack_copy_attr_times(dentry->d_inode,
-+					lower_file->f_path.dentry->d_inode);
-+		UNIONFS_F(file)->wrote_to_file = true; /* for delayed copyup */
-+		unionfs_check_file(file);
-+	}
-+
-+out:
-+	if (dentry != dentry->d_parent)
-+		unionfs_unlock_dentry(dentry->d_parent);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+static int unionfs_file_readdir(struct file *file, void *dirent,
-+				filldir_t filldir)
-+{
-+	return -ENOTDIR;
-+}
-+
-+static int unionfs_mmap(struct file *file, struct vm_area_struct *vma)
-+{
-+	int err = 0;
-+	bool willwrite;
-+	struct file *lower_file;
-+	struct dentry *dentry = file->f_path.dentry;
-+	struct vm_operations_struct *saved_vm_ops = NULL;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	/* This might be deferred to mmap's writepage */
-+	willwrite = ((vma->vm_flags | VM_SHARED | VM_WRITE) == vma->vm_flags);
-+	err = unionfs_file_revalidate(file, willwrite);
-+	if (unlikely(err))
-+		goto out;
-+	unionfs_check_file(file);
-+
-+	/*
-+	 * File systems which do not implement ->writepage may use
-+	 * generic_file_readonly_mmap as their ->mmap op.  If you call
-+	 * generic_file_readonly_mmap with VM_WRITE, you'd get an -EINVAL.
-+	 * But we cannot call the lower ->mmap op, so we can't tell that
-+	 * writeable mappings won't work.  Therefore, our only choice is to
-+	 * check if the lower file system supports the ->writepage, and if
-+	 * not, return EINVAL (the same error that
-+	 * generic_file_readonly_mmap returns in that case).
-+	 */
-+	lower_file = unionfs_lower_file(file);
-+	if (willwrite && !lower_file->f_mapping->a_ops->writepage) {
-+		err = -EINVAL;
-+		printk(KERN_ERR "unionfs: branch %d file system does not "
-+		       "support writeable mmap\n", fbstart(file));
-+		goto out;
-+	}
-+
-+	/*
-+	 * find and save lower vm_ops.
-+	 *
-+	 * XXX: the VFS should have a cleaner way of finding the lower vm_ops
-+	 */
-+	if (!UNIONFS_F(file)->lower_vm_ops) {
-+		err = lower_file->f_op->mmap(lower_file, vma);
-+		if (err) {
-+			printk(KERN_ERR "unionfs: lower mmap failed %d\n", err);
-+			goto out;
-+		}
-+		saved_vm_ops = vma->vm_ops;
-+		err = do_munmap(current->mm, vma->vm_start,
-+				vma->vm_end - vma->vm_start);
-+		if (err) {
-+			printk(KERN_ERR "unionfs: do_munmap failed %d\n", err);
-+			goto out;
-+		}
-+	}
-+
-+	file->f_mapping->a_ops = &unionfs_dummy_aops;
-+	err = generic_file_mmap(file, vma);
-+	file->f_mapping->a_ops = &unionfs_aops;
-+	if (err) {
-+		printk(KERN_ERR "unionfs: generic_file_mmap failed %d\n", err);
-+		goto out;
-+	}
-+	vma->vm_ops = &unionfs_vm_ops;
-+	if (!UNIONFS_F(file)->lower_vm_ops)
-+		UNIONFS_F(file)->lower_vm_ops = saved_vm_ops;
-+
-+out:
-+	if (!err) {
-+		/* copyup could cause parent dir times to change */
-+		unionfs_copy_attr_times(dentry->d_parent->d_inode);
-+		unionfs_check_file(file);
-+	}
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+int unionfs_fsync(struct file *file, struct dentry *dentry, int datasync)
-+{
-+	int bindex, bstart, bend;
-+	struct file *lower_file;
-+	struct dentry *lower_dentry;
-+	struct inode *lower_inode, *inode;
-+	int err = -EINVAL;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	err = unionfs_file_revalidate(file, true);
-+	if (unlikely(err))
-+		goto out;
-+	unionfs_check_file(file);
-+
-+	bstart = fbstart(file);
-+	bend = fbend(file);
-+	if (bstart < 0 || bend < 0)
-+		goto out;
-+
-+	inode = dentry->d_inode;
-+	if (unlikely(!inode)) {
-+		printk(KERN_ERR
-+		       "unionfs: null lower inode in unionfs_fsync\n");
-+		goto out;
-+	}
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (!lower_inode || !lower_inode->i_fop->fsync)
-+			continue;
-+		lower_file = unionfs_lower_file_idx(file, bindex);
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		mutex_lock(&lower_inode->i_mutex);
-+		err = lower_inode->i_fop->fsync(lower_file,
-+						lower_dentry,
-+						datasync);
-+		if (!err && bindex == bstart)
-+			fsstack_copy_attr_times(inode, lower_inode);
-+		mutex_unlock(&lower_inode->i_mutex);
-+		if (err)
-+			goto out;
-+	}
-+
-+out:
-+	if (!err)
-+		unionfs_check_file(file);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+int unionfs_fasync(int fd, struct file *file, int flag)
-+{
-+	int bindex, bstart, bend;
-+	struct file *lower_file;
-+	struct dentry *dentry = file->f_path.dentry;
-+	struct inode *lower_inode, *inode;
-+	int err = 0;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	err = unionfs_file_revalidate(file, true);
-+	if (unlikely(err))
-+		goto out;
-+	unionfs_check_file(file);
-+
-+	bstart = fbstart(file);
-+	bend = fbend(file);
-+	if (bstart < 0 || bend < 0)
-+		goto out;
-+
-+	inode = dentry->d_inode;
-+	if (unlikely(!inode)) {
-+		printk(KERN_ERR
-+		       "unionfs: null lower inode in unionfs_fasync\n");
-+		goto out;
-+	}
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (!lower_inode || !lower_inode->i_fop->fasync)
-+			continue;
-+		lower_file = unionfs_lower_file_idx(file, bindex);
-+		mutex_lock(&lower_inode->i_mutex);
-+		err = lower_inode->i_fop->fasync(fd, lower_file, flag);
-+		if (!err && bindex == bstart)
-+			fsstack_copy_attr_times(inode, lower_inode);
-+		mutex_unlock(&lower_inode->i_mutex);
-+		if (err)
-+			goto out;
-+	}
-+
-+out:
-+	if (!err)
-+		unionfs_check_file(file);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+static ssize_t unionfs_splice_read(struct file *file, loff_t *ppos,
-+				   struct pipe_inode_info *pipe, size_t len,
-+				   unsigned int flags)
-+{
-+	ssize_t err;
-+	struct file *lower_file;
-+	struct dentry *dentry = file->f_path.dentry;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	err = unionfs_file_revalidate(file, false);
-+	if (unlikely(err))
-+		goto out;
-+
-+	lower_file = unionfs_lower_file(file);
-+	err = vfs_splice_to(lower_file, ppos, pipe, len, flags);
-+	/* update our inode atime upon a successful lower splice-read */
-+	if (err >= 0) {
-+		fsstack_copy_attr_atime(dentry->d_inode,
-+					lower_file->f_path.dentry->d_inode);
-+		unionfs_check_file(file);
-+	}
-+
-+out:
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+static ssize_t unionfs_splice_write(struct pipe_inode_info *pipe,
-+				    struct file *file, loff_t *ppos,
-+				    size_t len, unsigned int flags)
-+{
-+	ssize_t err = 0;
-+	struct file *lower_file;
-+	struct dentry *dentry = file->f_path.dentry;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	err = unionfs_file_revalidate(file, true);
-+	if (unlikely(err))
-+		goto out;
-+
-+	lower_file = unionfs_lower_file(file);
-+	err = vfs_splice_from(pipe, lower_file, ppos, len, flags);
-+	/* update our inode times+sizes upon a successful lower write */
-+	if (err >= 0) {
-+		fsstack_copy_inode_size(dentry->d_inode,
-+					lower_file->f_path.dentry->d_inode);
-+		fsstack_copy_attr_times(dentry->d_inode,
-+					lower_file->f_path.dentry->d_inode);
-+		unionfs_check_file(file);
-+	}
-+
-+out:
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+struct file_operations unionfs_main_fops = {
-+	.llseek		= generic_file_llseek,
-+	.read		= unionfs_read,
-+	.write		= unionfs_write,
-+	.readdir	= unionfs_file_readdir,
-+	.unlocked_ioctl	= unionfs_ioctl,
-+	.mmap		= unionfs_mmap,
-+	.open		= unionfs_open,
-+	.flush		= unionfs_flush,
-+	.release	= unionfs_file_release,
-+	.fsync		= unionfs_fsync,
-+	.fasync		= unionfs_fasync,
-+	.splice_read	= unionfs_splice_read,
-+	.splice_write	= unionfs_splice_write,
-+};
-diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c
-new file mode 100644
-index 0000000..0bd9fab
---- /dev/null
-+++ b/fs/unionfs/inode.c
-@@ -0,0 +1,984 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Find a writeable branch to create new object in.  Checks all writeble
-+ * branches of the parent inode, from istart to iend order; if none are
-+ * suitable, also tries branch 0 (which may require a copyup).
-+ *
-+ * Return a lower_dentry we can use to create object in, or ERR_PTR.
-+ */
-+static struct dentry *find_writeable_branch(struct inode *parent,
-+					    struct dentry *dentry)
-+{
-+	int err = -EINVAL;
-+	int bindex, istart, iend;
-+	struct dentry *lower_dentry = NULL;
-+
-+	istart = ibstart(parent);
-+	iend = ibend(parent);
-+	if (istart < 0)
-+		goto out;
-+
-+begin:
-+	for (bindex = istart; bindex <= iend; bindex++) {
-+		/* skip non-writeable branches */
-+		err = is_robranch_super(dentry->d_sb, bindex);
-+		if (err) {
-+			err = -EROFS;
-+			continue;
-+		}
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry)
-+			continue;
-+		/*
-+		 * check for whiteouts in writeable branch, and remove them
-+		 * if necessary.
-+		 */
-+		err = check_unlink_whiteout(dentry, lower_dentry, bindex);
-+		if (err > 0)	/* ignore if whiteout found and removed */
-+			err = 0;
-+		if (err)
-+			continue;
-+		/* if get here, we can write to the branch */
-+		break;
-+	}
-+	/*
-+	 * If istart wasn't already branch 0, and we got any error, then try
-+	 * branch 0 (which may require copyup)
-+	 */
-+	if (err && istart > 0) {
-+		istart = iend = 0;
-+		goto begin;
-+	}
-+
-+	/*
-+	 * If we tried even branch 0, and still got an error, abort.  But if
-+	 * the error was an EROFS, then we should try to copyup.
-+	 */
-+	if (err && err != -EROFS)
-+		goto out;
-+
-+	/*
-+	 * If we get here, then check if copyup needed.  If lower_dentry is
-+	 * NULL, create the entire dentry directory structure in branch 0.
-+	 */
-+	if (!lower_dentry) {
-+		bindex = 0;
-+		lower_dentry = create_parents(parent, dentry,
-+					      dentry->d_name.name, bindex);
-+		if (IS_ERR(lower_dentry)) {
-+			err = PTR_ERR(lower_dentry);
-+			goto out;
-+		}
-+	}
-+	err = 0;		/* all's well */
-+out:
-+	if (err)
-+		return ERR_PTR(err);
-+	return lower_dentry;
-+}
-+
-+static int unionfs_create(struct inode *parent, struct dentry *dentry,
-+			  int mode, struct nameidata *nd)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry = NULL;
-+	struct dentry *lower_parent_dentry = NULL;
-+	int valid = 0;
-+	struct nameidata lower_nd;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
-+
-+	valid = __unionfs_d_revalidate_chain(dentry->d_parent, nd, false);
-+	if (unlikely(!valid)) {
-+		err = -ESTALE;	/* same as what real_lookup does */
-+		goto out;
-+	}
-+
-+	valid = __unionfs_d_revalidate_one_locked(dentry, nd, false);
-+	/*
-+	 * It's only a bug if this dentry was not negative and couldn't be
-+	 * revalidated (shouldn't happen).
-+	 */
-+	BUG_ON(!valid && dentry->d_inode);
-+
-+	lower_dentry = find_writeable_branch(parent, dentry);
-+	if (IS_ERR(lower_dentry)) {
-+		err = PTR_ERR(lower_dentry);
-+		goto out;
-+	}
-+
-+	lower_parent_dentry = lock_parent(lower_dentry);
-+	if (IS_ERR(lower_parent_dentry)) {
-+		err = PTR_ERR(lower_parent_dentry);
-+		goto out;
-+	}
-+
-+	err = init_lower_nd(&lower_nd, LOOKUP_CREATE);
-+	if (unlikely(err < 0))
-+		goto out;
-+	err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode,
-+			 &lower_nd);
-+	release_lower_nd(&lower_nd, err);
-+
-+	if (!err) {
-+		err = PTR_ERR(unionfs_interpose(dentry, parent->i_sb, 0));
-+		if (!err) {
-+			unionfs_copy_attr_times(parent);
-+			fsstack_copy_inode_size(parent,
-+						lower_parent_dentry->d_inode);
-+			/* update no. of links on parent directory */
-+			parent->i_nlink = unionfs_get_nlinks(parent);
-+		}
-+	}
-+
-+	unlock_dir(lower_parent_dentry);
-+
-+out:
-+	if (!err) {
-+		unionfs_postcopyup_setmnt(dentry);
-+		unionfs_check_inode(parent);
-+		unionfs_check_dentry(dentry);
-+		unionfs_check_nd(nd);
-+	}
-+	unionfs_unlock_dentry(dentry->d_parent);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+/*
-+ * unionfs_lookup is the only special function which takes a dentry, yet we
-+ * do NOT want to call __unionfs_d_revalidate_chain because by definition,
-+ * we don't have a valid dentry here yet.
-+ */
-+static struct dentry *unionfs_lookup(struct inode *parent,
-+				     struct dentry *dentry,
-+				     struct nameidata *nd)
-+{
-+	struct path path_save = {NULL, NULL};
-+	struct dentry *ret;
-+	int err = 0;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	if (dentry != dentry->d_parent)
-+		unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_ROOT);
-+
-+	/* save the dentry & vfsmnt from namei */
-+	if (nd) {
-+		path_save.dentry = nd->path.dentry;
-+		path_save.mnt = nd->path.mnt;
-+	}
-+
-+	/*
-+	 * unionfs_lookup_backend returns a locked dentry upon success,
-+	 * so we'll have to unlock it below.
-+	 */
-+
-+	/* allocate dentry private data.  We free it in ->d_release */
-+	err = new_dentry_private_data(dentry, UNIONFS_DMUTEX_CHILD);
-+	if (unlikely(err)) {
-+		ret = ERR_PTR(err);
-+		goto out;
-+	}
-+	ret = unionfs_lookup_full(dentry, nd, INTERPOSE_LOOKUP);
-+
-+	/* restore the dentry & vfsmnt in namei */
-+	if (nd) {
-+		nd->path.dentry = path_save.dentry;
-+		nd->path.mnt = path_save.mnt;
-+	}
-+	if (!IS_ERR(ret)) {
-+		if (ret)
-+			dentry = ret;
-+		/* lookup_full can return multiple positive dentries */
-+		if (dentry->d_inode && !S_ISDIR(dentry->d_inode->i_mode)) {
-+			BUG_ON(dbstart(dentry) < 0);
-+			unionfs_postcopyup_release(dentry);
-+		}
-+		unionfs_copy_attr_times(dentry->d_inode);
-+		/* parent times may have changed */
-+		unionfs_copy_attr_times(dentry->d_parent->d_inode);
-+	}
-+
-+	unionfs_check_inode(parent);
-+	if (!IS_ERR(ret)) {
-+		unionfs_check_dentry(dentry);
-+		unionfs_check_nd(nd);
-+	}
-+	unionfs_unlock_dentry(dentry);
-+
-+out:
-+	if (dentry != dentry->d_parent) {
-+		unionfs_check_dentry(dentry->d_parent);
-+		unionfs_unlock_dentry(dentry->d_parent);
-+	}
-+	unionfs_read_unlock(dentry->d_sb);
-+
-+	return ret;
-+}
-+
-+static int unionfs_link(struct dentry *old_dentry, struct inode *dir,
-+			struct dentry *new_dentry)
-+{
-+	int err = 0;
-+	struct dentry *lower_old_dentry = NULL;
-+	struct dentry *lower_new_dentry = NULL;
-+	struct dentry *lower_dir_dentry = NULL;
-+	char *name = NULL;
-+
-+	unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_double_lock_dentry(new_dentry, old_dentry);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(old_dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+	if (unlikely(new_dentry->d_inode &&
-+		     !__unionfs_d_revalidate_chain(new_dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	lower_new_dentry = unionfs_lower_dentry(new_dentry);
-+
-+	/* check for a whiteout in new dentry branch, and delete it */
-+	err = check_unlink_whiteout(new_dentry, lower_new_dentry,
-+				    dbstart(new_dentry));
-+	if (err > 0) {	       /* whiteout found and removed successfully */
-+		lower_dir_dentry = dget_parent(lower_new_dentry);
-+		fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-+		dput(lower_dir_dentry);
-+		dir->i_nlink = unionfs_get_nlinks(dir);
-+		err = 0;
-+	}
-+	if (err)
-+		goto out;
-+
-+	/* check if parent hierachy is needed, then link in same branch */
-+	if (dbstart(old_dentry) != dbstart(new_dentry)) {
-+		lower_new_dentry = create_parents(dir, new_dentry,
-+						  new_dentry->d_name.name,
-+						  dbstart(old_dentry));
-+		err = PTR_ERR(lower_new_dentry);
-+		if (IS_COPYUP_ERR(err))
-+			goto docopyup;
-+		if (!lower_new_dentry || IS_ERR(lower_new_dentry))
-+			goto out;
-+	}
-+	lower_new_dentry = unionfs_lower_dentry(new_dentry);
-+	lower_old_dentry = unionfs_lower_dentry(old_dentry);
-+
-+	BUG_ON(dbstart(old_dentry) != dbstart(new_dentry));
-+	lower_dir_dentry = lock_parent(lower_new_dentry);
-+	err = is_robranch(old_dentry);
-+	if (!err) {
-+		/* see Documentation/filesystems/unionfs/issues.txt */
-+		lockdep_off();
-+		err = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
-+			       lower_new_dentry);
-+		lockdep_on();
-+	}
-+	unlock_dir(lower_dir_dentry);
-+
-+docopyup:
-+	if (IS_COPYUP_ERR(err)) {
-+		int old_bstart = dbstart(old_dentry);
-+		int bindex;
-+
-+		for (bindex = old_bstart - 1; bindex >= 0; bindex--) {
-+			err = copyup_dentry(old_dentry->d_parent->d_inode,
-+					    old_dentry, old_bstart,
-+					    bindex, old_dentry->d_name.name,
-+					    old_dentry->d_name.len, NULL,
-+					    i_size_read(old_dentry->d_inode));
-+			if (err)
-+				continue;
-+			lower_new_dentry =
-+				create_parents(dir, new_dentry,
-+					       new_dentry->d_name.name,
-+					       bindex);
-+			lower_old_dentry = unionfs_lower_dentry(old_dentry);
-+			lower_dir_dentry = lock_parent(lower_new_dentry);
-+			/* see Documentation/filesystems/unionfs/issues.txt */
-+			lockdep_off();
-+			/* do vfs_link */
-+			err = vfs_link(lower_old_dentry,
-+				       lower_dir_dentry->d_inode,
-+				       lower_new_dentry);
-+			lockdep_on();
-+			unlock_dir(lower_dir_dentry);
-+			goto check_link;
-+		}
-+		goto out;
-+	}
-+
-+check_link:
-+	if (err || !lower_new_dentry->d_inode)
-+		goto out;
-+
-+	/* Its a hard link, so use the same inode */
-+	new_dentry->d_inode = igrab(old_dentry->d_inode);
-+	d_add(new_dentry, new_dentry->d_inode);
-+	unionfs_copy_attr_all(dir, lower_new_dentry->d_parent->d_inode);
-+	fsstack_copy_inode_size(dir, lower_new_dentry->d_parent->d_inode);
-+
-+	/* propagate number of hard-links */
-+	old_dentry->d_inode->i_nlink = unionfs_get_nlinks(old_dentry->d_inode);
-+	/* new dentry's ctime may have changed due to hard-link counts */
-+	unionfs_copy_attr_times(new_dentry->d_inode);
-+
-+out:
-+	if (!new_dentry->d_inode)
-+		d_drop(new_dentry);
-+
-+	kfree(name);
-+	if (!err)
-+		unionfs_postcopyup_setmnt(new_dentry);
-+
-+	unionfs_check_inode(dir);
-+	unionfs_check_dentry(new_dentry);
-+	unionfs_check_dentry(old_dentry);
-+
-+	unionfs_unlock_dentry(new_dentry);
-+	unionfs_unlock_dentry(old_dentry);
-+	unionfs_read_unlock(old_dentry->d_sb);
-+
-+	return err;
-+}
-+
-+static int unionfs_symlink(struct inode *parent, struct dentry *dentry,
-+			   const char *symname)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry = NULL;
-+	struct dentry *wh_dentry = NULL;
-+	struct dentry *lower_parent_dentry = NULL;
-+	char *name = NULL;
-+	int valid = 0;
-+	umode_t mode;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
-+
-+	valid = __unionfs_d_revalidate_chain(dentry->d_parent, NULL, false);
-+	if (unlikely(!valid)) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+	if (unlikely(dentry->d_inode &&
-+		     !__unionfs_d_revalidate_one_locked(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	/*
-+	 * It's only a bug if this dentry was not negative and couldn't be
-+	 * revalidated (shouldn't happen).
-+	 */
-+	BUG_ON(!valid && dentry->d_inode);
-+
-+	lower_dentry = find_writeable_branch(parent, dentry);
-+	if (IS_ERR(lower_dentry)) {
-+		err = PTR_ERR(lower_dentry);
-+		goto out;
-+	}
-+
-+	lower_parent_dentry = lock_parent(lower_dentry);
-+	if (IS_ERR(lower_parent_dentry)) {
-+		err = PTR_ERR(lower_parent_dentry);
-+		goto out;
-+	}
-+
-+	mode = S_IALLUGO;
-+	err = vfs_symlink(lower_parent_dentry->d_inode, lower_dentry, symname);
-+	if (!err) {
-+		err = PTR_ERR(unionfs_interpose(dentry, parent->i_sb, 0));
-+		if (!err) {
-+			unionfs_copy_attr_times(parent);
-+			fsstack_copy_inode_size(parent,
-+						lower_parent_dentry->d_inode);
-+			/* update no. of links on parent directory */
-+			parent->i_nlink = unionfs_get_nlinks(parent);
-+		}
-+	}
-+
-+	unlock_dir(lower_parent_dentry);
-+
-+out:
-+	dput(wh_dentry);
-+	kfree(name);
-+
-+	if (!err) {
-+		unionfs_postcopyup_setmnt(dentry);
-+		unionfs_check_inode(parent);
-+		unionfs_check_dentry(dentry);
-+	}
-+	unionfs_unlock_dentry(dentry->d_parent);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+static int unionfs_mkdir(struct inode *parent, struct dentry *dentry, int mode)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry = NULL;
-+	struct dentry *lower_parent_dentry = NULL;
-+	int bindex = 0, bstart;
-+	char *name = NULL;
-+	int valid;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
-+
-+	valid = __unionfs_d_revalidate_chain(dentry->d_parent, NULL, false);
-+	if (unlikely(!valid)) {
-+		err = -ESTALE;	/* same as what real_lookup does */
-+		goto out;
-+	}
-+	if (unlikely(dentry->d_inode &&
-+		     !__unionfs_d_revalidate_one_locked(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	bstart = dbstart(dentry);
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+
-+	/* check for a whiteout in new dentry branch, and delete it */
-+	err = check_unlink_whiteout(dentry, lower_dentry, bstart);
-+	if (err > 0)	       /* whiteout found and removed successfully */
-+		err = 0;
-+	if (err) {
-+		/* exit if the error returned was NOT -EROFS */
-+		if (!IS_COPYUP_ERR(err))
-+			goto out;
-+		bstart--;
-+	}
-+
-+	/* check if copyup's needed, and mkdir */
-+	for (bindex = bstart; bindex >= 0; bindex--) {
-+		int i;
-+		int bend = dbend(dentry);
-+
-+		if (is_robranch_super(dentry->d_sb, bindex))
-+			continue;
-+
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry) {
-+			lower_dentry = create_parents(parent, dentry,
-+						      dentry->d_name.name,
-+						      bindex);
-+			if (!lower_dentry || IS_ERR(lower_dentry)) {
-+				printk(KERN_ERR "unionfs: lower dentry "
-+				       " NULL for bindex = %d\n", bindex);
-+				continue;
-+			}
-+		}
-+
-+		lower_parent_dentry = lock_parent(lower_dentry);
-+
-+		if (IS_ERR(lower_parent_dentry)) {
-+			err = PTR_ERR(lower_parent_dentry);
-+			goto out;
-+		}
-+
-+		err = vfs_mkdir(lower_parent_dentry->d_inode, lower_dentry,
-+				mode);
-+
-+		unlock_dir(lower_parent_dentry);
-+
-+		/* did the mkdir succeed? */
-+		if (err)
-+			break;
-+
-+		for (i = bindex + 1; i < bend; i++) {
-+			if (unionfs_lower_dentry_idx(dentry, i)) {
-+				dput(unionfs_lower_dentry_idx(dentry, i));
-+				unionfs_set_lower_dentry_idx(dentry, i, NULL);
-+			}
-+		}
-+		dbend(dentry) = bindex;
-+
-+		/*
-+		 * Only INTERPOSE_LOOKUP can return a value other than 0 on
-+		 * err.
-+		 */
-+		err = PTR_ERR(unionfs_interpose(dentry, parent->i_sb, 0));
-+		if (!err) {
-+			unionfs_copy_attr_times(parent);
-+			fsstack_copy_inode_size(parent,
-+						lower_parent_dentry->d_inode);
-+
-+			/* update number of links on parent directory */
-+			parent->i_nlink = unionfs_get_nlinks(parent);
-+		}
-+
-+		err = make_dir_opaque(dentry, dbstart(dentry));
-+		if (err) {
-+			printk(KERN_ERR "unionfs: mkdir: error creating "
-+			       ".wh.__dir_opaque: %d\n", err);
-+			goto out;
-+		}
-+
-+		/* we are done! */
-+		break;
-+	}
-+
-+out:
-+	if (!dentry->d_inode)
-+		d_drop(dentry);
-+
-+	kfree(name);
-+
-+	if (!err) {
-+		unionfs_copy_attr_times(dentry->d_inode);
-+		unionfs_postcopyup_setmnt(dentry);
-+	}
-+	unionfs_check_inode(parent);
-+	unionfs_check_dentry(dentry);
-+	unionfs_unlock_dentry(dentry->d_parent);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+
-+	return err;
-+}
-+
-+static int unionfs_mknod(struct inode *parent, struct dentry *dentry, int mode,
-+			 dev_t dev)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry = NULL;
-+	struct dentry *wh_dentry = NULL;
-+	struct dentry *lower_parent_dentry = NULL;
-+	char *name = NULL;
-+	int valid = 0;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
-+
-+	valid = __unionfs_d_revalidate_chain(dentry->d_parent, NULL, false);
-+	if (unlikely(!valid)) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+	if (unlikely(dentry->d_inode &&
-+		     !__unionfs_d_revalidate_one_locked(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	/*
-+	 * It's only a bug if this dentry was not negative and couldn't be
-+	 * revalidated (shouldn't happen).
-+	 */
-+	BUG_ON(!valid && dentry->d_inode);
-+
-+	lower_dentry = find_writeable_branch(parent, dentry);
-+	if (IS_ERR(lower_dentry)) {
-+		err = PTR_ERR(lower_dentry);
-+		goto out;
-+	}
-+
-+	lower_parent_dentry = lock_parent(lower_dentry);
-+	if (IS_ERR(lower_parent_dentry)) {
-+		err = PTR_ERR(lower_parent_dentry);
-+		goto out;
-+	}
-+
-+	err = vfs_mknod(lower_parent_dentry->d_inode, lower_dentry, mode, dev);
-+	if (!err) {
-+		err = PTR_ERR(unionfs_interpose(dentry, parent->i_sb, 0));
-+		if (!err) {
-+			unionfs_copy_attr_times(parent);
-+			fsstack_copy_inode_size(parent,
-+						lower_parent_dentry->d_inode);
-+			/* update no. of links on parent directory */
-+			parent->i_nlink = unionfs_get_nlinks(parent);
-+		}
-+	}
-+
-+	unlock_dir(lower_parent_dentry);
-+
-+out:
-+	dput(wh_dentry);
-+	kfree(name);
-+
-+	if (!err) {
-+		unionfs_postcopyup_setmnt(dentry);
-+		unionfs_check_inode(parent);
-+		unionfs_check_dentry(dentry);
-+	}
-+	unionfs_unlock_dentry(dentry->d_parent);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+static int unionfs_readlink(struct dentry *dentry, char __user *buf,
-+			    int bufsiz)
-+{
-+	int err;
-+	struct dentry *lower_dentry;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+
-+	if (!lower_dentry->d_inode->i_op ||
-+	    !lower_dentry->d_inode->i_op->readlink) {
-+		err = -EINVAL;
-+		goto out;
-+	}
-+
-+	err = lower_dentry->d_inode->i_op->readlink(lower_dentry,
-+						    buf, bufsiz);
-+	if (err > 0)
-+		fsstack_copy_attr_atime(dentry->d_inode,
-+					lower_dentry->d_inode);
-+
-+out:
-+	unionfs_check_dentry(dentry);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+
-+	return err;
-+}
-+
-+/*
-+ * unionfs_follow_link takes a dentry, but it is simple.  It only needs to
-+ * allocate some memory and then call our ->readlink method.  Our
-+ * unionfs_readlink *does* lock our dentry and revalidate the dentry.
-+ * Therefore, we do not have to lock our dentry here, to prevent a deadlock;
-+ * nor do we need to revalidate it either.  It is safe to not lock our
-+ * dentry here, nor revalidate it, because unionfs_follow_link does not do
-+ * anything (prior to calling ->readlink) which could become inconsistent
-+ * due to branch management.  We also don't need to lock our super because
-+ * this function isn't affected by branch-management.
-+ */
-+static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd)
-+{
-+	char *buf;
-+	int len = PAGE_SIZE, err;
-+	mm_segment_t old_fs;
-+
-+	/* This is freed by the put_link method assuming a successful call. */
-+	buf = kmalloc(len, GFP_KERNEL);
-+	if (unlikely(!buf)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+
-+	/* read the symlink, and then we will follow it */
-+	old_fs = get_fs();
-+	set_fs(KERNEL_DS);
-+	err = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
-+	set_fs(old_fs);
-+	if (err < 0) {
-+		kfree(buf);
-+		buf = NULL;
-+		goto out;
-+	}
-+	buf[err] = 0;
-+	nd_set_link(nd, buf);
-+	err = 0;
-+
-+out:
-+	if (!err) {
-+		unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+		unionfs_check_dentry(dentry);
-+		unionfs_unlock_dentry(dentry);
-+	}
-+	unionfs_check_nd(nd);
-+	return ERR_PTR(err);
-+}
-+
-+/* FIXME: We may not have to lock here */
-+static void unionfs_put_link(struct dentry *dentry, struct nameidata *nd,
-+			     void *cookie)
-+{
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, nd, false)))
-+		printk(KERN_ERR
-+		       "unionfs: put_link failed to revalidate dentry\n");
-+
-+	unionfs_check_dentry(dentry);
-+	unionfs_check_nd(nd);
-+	kfree(nd_get_link(nd));
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+}
-+
-+/*
-+ * Don't grab the superblock read-lock in unionfs_permission, which prevents
-+ * a deadlock with the branch-management "add branch" code (which grabbed
-+ * the write lock).  It is safe to not grab the read lock here, because even
-+ * with branch management taking place, there is no chance that
-+ * unionfs_permission, or anything it calls, will use stale branch
-+ * information.
-+ */
-+static int unionfs_permission(struct inode *inode, int mask)
-+{
-+	struct inode *lower_inode = NULL;
-+	int err = 0;
-+	int bindex, bstart, bend;
-+	const int is_file = !S_ISDIR(inode->i_mode);
-+	const int write_mask = (mask & MAY_WRITE) && !(mask & MAY_READ);
-+
-+	if (!UNIONFS_I(inode)->lower_inodes) {
-+		if (is_file)	/* dirs can be unlinked but chdir'ed to */
-+			err = -ESTALE;	/* force revalidate */
-+		goto out;
-+	}
-+	bstart = ibstart(inode);
-+	bend = ibend(inode);
-+	if (unlikely(bstart < 0 || bend < 0)) {
-+		/*
-+		 * With branch-management, we can get a stale inode here.
-+		 * If so, we return ESTALE back to link_path_walk, which
-+		 * would discard the dcache entry and re-lookup the
-+		 * dentry+inode.  This should be equivalent to issuing
-+		 * __unionfs_d_revalidate_chain on nd.dentry here.
-+		 */
-+		if (is_file)	/* dirs can be unlinked but chdir'ed to */
-+			err = -ESTALE;	/* force revalidate */
-+		goto out;
-+	}
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (!lower_inode)
-+			continue;
-+
-+		/*
-+		 * check the condition for D-F-D underlying files/directories,
-+		 * we don't have to check for files, if we are checking for
-+		 * directories.
-+		 */
-+		if (!is_file && !S_ISDIR(lower_inode->i_mode))
-+			continue;
-+
-+		/*
-+		 * We check basic permissions, but we ignore any conditions
-+		 * such as readonly file systems or branches marked as
-+		 * readonly, because those conditions should lead to a
-+		 * copyup taking place later on.
-+		 */
-+		err = inode_permission(lower_inode, mask);
-+		if (err && bindex > 0) {
-+			umode_t mode = lower_inode->i_mode;
-+			if (is_robranch_super(inode->i_sb, bindex) &&
-+			    (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
-+				err = 0;
-+			if (IS_COPYUP_ERR(err))
-+				err = 0;
-+		}
-+
-+		/*
-+		 * The permissions are an intersection of the overall directory
-+		 * permissions, so we fail if one fails.
-+		 */
-+		if (err)
-+			goto out;
-+
-+		/* only the leftmost file matters. */
-+		if (is_file || write_mask) {
-+			if (is_file && write_mask) {
-+				err = get_write_access(lower_inode);
-+				if (!err)
-+					put_write_access(lower_inode);
-+			}
-+			break;
-+		}
-+	}
-+	/* sync times which may have changed (asynchronously) below */
-+	unionfs_copy_attr_times(inode);
-+
-+out:
-+	unionfs_check_inode(inode);
-+	return err;
-+}
-+
-+static int unionfs_setattr(struct dentry *dentry, struct iattr *ia)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry;
-+	struct inode *inode;
-+	struct inode *lower_inode;
-+	int bstart, bend, bindex;
-+	loff_t size;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+	inode = dentry->d_inode;
-+
-+	/*
-+	 * mode change is for clearing setuid/setgid. Allow lower filesystem
-+	 * to reinterpret it in its own way.
-+	 */
-+	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
-+		ia->ia_valid &= ~ATTR_MODE;
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+	BUG_ON(!lower_dentry);	/* should never happen after above revalidate */
-+
-+	/* copyup if the file is on a read only branch */
-+	if (is_robranch_super(dentry->d_sb, bstart)
-+	    || IS_RDONLY(lower_dentry->d_inode)) {
-+		/* check if we have a branch to copy up to */
-+		if (bstart <= 0) {
-+			err = -EACCES;
-+			goto out;
-+		}
-+
-+		if (ia->ia_valid & ATTR_SIZE)
-+			size = ia->ia_size;
-+		else
-+			size = i_size_read(inode);
-+		/* copyup to next available branch */
-+		for (bindex = bstart - 1; bindex >= 0; bindex--) {
-+			err = copyup_dentry(dentry->d_parent->d_inode,
-+					    dentry, bstart, bindex,
-+					    dentry->d_name.name,
-+					    dentry->d_name.len,
-+					    NULL, size);
-+			if (!err)
-+				break;
-+		}
-+		if (err)
-+			goto out;
-+		/* get updated lower_dentry after copyup */
-+		lower_dentry = unionfs_lower_dentry(dentry);
-+	}
-+
-+	lower_inode = unionfs_lower_inode(inode);
-+
-+	/*
-+	 * If shrinking, first truncate upper level to cancel writing dirty
-+	 * pages beyond the new eof; and also if its' maxbytes is more
-+	 * limiting (fail with -EFBIG before making any change to the lower
-+	 * level).  There is no need to vmtruncate the upper level
-+	 * afterwards in the other cases: we fsstack_copy_inode_size from
-+	 * the lower level.
-+	 */
-+	if (ia->ia_valid & ATTR_SIZE) {
-+		size = i_size_read(inode);
-+		if (ia->ia_size < size || (ia->ia_size > size &&
-+		    inode->i_sb->s_maxbytes < lower_inode->i_sb->s_maxbytes)) {
-+			err = vmtruncate(inode, ia->ia_size);
-+			if (err)
-+				goto out;
-+		}
-+	}
-+
-+	/* notify the (possibly copied-up) lower inode */
-+	mutex_lock(&lower_dentry->d_inode->i_mutex);
-+	err = notify_change(lower_dentry, ia);
-+	mutex_unlock(&lower_dentry->d_inode->i_mutex);
-+	if (err)
-+		goto out;
-+
-+	/* get attributes from the first lower inode */
-+	unionfs_copy_attr_all(inode, lower_inode);
-+	/*
-+	 * unionfs_copy_attr_all will copy the lower times to our inode if
-+	 * the lower ones are newer (useful for cache coherency).  However,
-+	 * ->setattr is the only place in which we may have to copy the
-+	 * lower inode times absolutely, to support utimes(2).
-+	 */
-+	if (ia->ia_valid & ATTR_MTIME_SET)
-+		inode->i_mtime = lower_inode->i_mtime;
-+	if (ia->ia_valid & ATTR_CTIME)
-+		inode->i_ctime = lower_inode->i_ctime;
-+	if (ia->ia_valid & ATTR_ATIME_SET)
-+		inode->i_atime = lower_inode->i_atime;
-+	fsstack_copy_inode_size(inode, lower_inode);
-+
-+out:
-+	if (!err)
-+		unionfs_check_dentry(dentry);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+
-+	return err;
-+}
-+
-+struct inode_operations unionfs_symlink_iops = {
-+	.readlink	= unionfs_readlink,
-+	.permission	= unionfs_permission,
-+	.follow_link	= unionfs_follow_link,
-+	.setattr	= unionfs_setattr,
-+	.put_link	= unionfs_put_link,
-+};
-+
-+struct inode_operations unionfs_dir_iops = {
-+	.create		= unionfs_create,
-+	.lookup		= unionfs_lookup,
-+	.link		= unionfs_link,
-+	.unlink		= unionfs_unlink,
-+	.symlink	= unionfs_symlink,
-+	.mkdir		= unionfs_mkdir,
-+	.rmdir		= unionfs_rmdir,
-+	.mknod		= unionfs_mknod,
-+	.rename		= unionfs_rename,
-+	.permission	= unionfs_permission,
-+	.setattr	= unionfs_setattr,
-+#ifdef CONFIG_UNION_FS_XATTR
-+	.setxattr	= unionfs_setxattr,
-+	.getxattr	= unionfs_getxattr,
-+	.removexattr	= unionfs_removexattr,
-+	.listxattr	= unionfs_listxattr,
-+#endif /* CONFIG_UNION_FS_XATTR */
-+};
-+
-+struct inode_operations unionfs_main_iops = {
-+	.permission	= unionfs_permission,
-+	.setattr	= unionfs_setattr,
-+#ifdef CONFIG_UNION_FS_XATTR
-+	.setxattr	= unionfs_setxattr,
-+	.getxattr	= unionfs_getxattr,
-+	.removexattr	= unionfs_removexattr,
-+	.listxattr	= unionfs_listxattr,
-+#endif /* CONFIG_UNION_FS_XATTR */
-+};
-diff --git a/fs/unionfs/lookup.c b/fs/unionfs/lookup.c
-new file mode 100644
-index 0000000..0a9602a
---- /dev/null
-+++ b/fs/unionfs/lookup.c
-@@ -0,0 +1,570 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Lookup one path component @name relative to a <base,mnt> path pair.
-+ * Behaves nearly the same as lookup_one_len (i.e., return negative dentry
-+ * on ENOENT), but uses the @mnt passed, so it can cross bind mounts and
-+ * other lower mounts properly.  If @new_mnt is non-null, will fill in the
-+ * new mnt there.  Caller is responsible to dput/mntput/path_put returned
-+ * @dentry and @new_mnt.
-+ */
-+struct dentry *__lookup_one(struct dentry *base, struct vfsmount *mnt,
-+			    const char *name, struct vfsmount **new_mnt)
-+{
-+	struct dentry *dentry = NULL;
-+	struct nameidata lower_nd;
-+	int err;
-+
-+	/* we use flags=0 to get basic lookup */
-+	err = vfs_path_lookup(base, mnt, name, 0, &lower_nd);
-+
-+	switch (err) {
-+	case 0: /* no error */
-+		dentry = lower_nd.path.dentry;
-+		if (new_mnt)
-+			*new_mnt = lower_nd.path.mnt; /* rc already inc'ed */
-+		break;
-+	case -ENOENT:
-+		 /*
-+		  * We don't consider ENOENT an error, and we want to return
-+		  * a negative dentry (ala lookup_one_len).  As we know
-+		  * there was no inode for this name before (-ENOENT), then
-+		  * it's safe to call lookup_one_len (which doesn't take a
-+		  * vfsmount).
-+		  */
-+		dentry = lookup_one_len(name, base, strlen(name));
-+		if (new_mnt)
-+			*new_mnt = mntget(lower_nd.path.mnt);
-+		break;
-+	default: /* all other real errors */
-+		dentry = ERR_PTR(err);
-+		break;
-+	}
-+
-+	return dentry;
-+}
-+
-+/*
-+ * This is a utility function that fills in a unionfs dentry.
-+ * Caller must lock this dentry with unionfs_lock_dentry.
-+ *
-+ * Returns: 0 (ok), or -ERRNO if an error occurred.
-+ * XXX: get rid of _partial_lookup and make callers call _lookup_full directly
-+ */
-+int unionfs_partial_lookup(struct dentry *dentry)
-+{
-+	struct dentry *tmp;
-+	struct nameidata nd = { .flags = 0 };
-+	int err = -ENOSYS;
-+
-+	tmp = unionfs_lookup_full(dentry, &nd, INTERPOSE_PARTIAL);
-+
-+	if (!tmp) {
-+		err = 0;
-+		goto out;
-+	}
-+	if (IS_ERR(tmp)) {
-+		err = PTR_ERR(tmp);
-+		goto out;
-+	}
-+	/* XXX: need to change the interface */
-+	BUG_ON(tmp != dentry);
-+out:
-+	return err;
-+}
-+
-+/* The dentry cache is just so we have properly sized dentries. */
-+static struct kmem_cache *unionfs_dentry_cachep;
-+int unionfs_init_dentry_cache(void)
-+{
-+	unionfs_dentry_cachep =
-+		kmem_cache_create("unionfs_dentry",
-+				  sizeof(struct unionfs_dentry_info),
-+				  0, SLAB_RECLAIM_ACCOUNT, NULL);
-+
-+	return (unionfs_dentry_cachep ? 0 : -ENOMEM);
-+}
-+
-+void unionfs_destroy_dentry_cache(void)
-+{
-+	if (unionfs_dentry_cachep)
-+		kmem_cache_destroy(unionfs_dentry_cachep);
-+}
-+
-+void free_dentry_private_data(struct dentry *dentry)
-+{
-+	if (!dentry || !dentry->d_fsdata)
-+		return;
-+	kfree(UNIONFS_D(dentry)->lower_paths);
-+	UNIONFS_D(dentry)->lower_paths = NULL;
-+	kmem_cache_free(unionfs_dentry_cachep, dentry->d_fsdata);
-+	dentry->d_fsdata = NULL;
-+}
-+
-+static inline int __realloc_dentry_private_data(struct dentry *dentry)
-+{
-+	struct unionfs_dentry_info *info = UNIONFS_D(dentry);
-+	void *p;
-+	int size;
-+
-+	BUG_ON(!info);
-+
-+	size = sizeof(struct path) * sbmax(dentry->d_sb);
-+	p = krealloc(info->lower_paths, size, GFP_ATOMIC);
-+	if (unlikely(!p))
-+		return -ENOMEM;
-+
-+	info->lower_paths = p;
-+
-+	info->bstart = -1;
-+	info->bend = -1;
-+	info->bopaque = -1;
-+	info->bcount = sbmax(dentry->d_sb);
-+	atomic_set(&info->generation,
-+			atomic_read(&UNIONFS_SB(dentry->d_sb)->generation));
-+
-+	memset(info->lower_paths, 0, size);
-+
-+	return 0;
-+}
-+
-+/* UNIONFS_D(dentry)->lock must be locked */
-+int realloc_dentry_private_data(struct dentry *dentry)
-+{
-+	if (!__realloc_dentry_private_data(dentry))
-+		return 0;
-+
-+	kfree(UNIONFS_D(dentry)->lower_paths);
-+	free_dentry_private_data(dentry);
-+	return -ENOMEM;
-+}
-+
-+/* allocate new dentry private data */
-+int new_dentry_private_data(struct dentry *dentry, int subclass)
-+{
-+	struct unionfs_dentry_info *info = UNIONFS_D(dentry);
-+
-+	BUG_ON(info);
-+
-+	info = kmem_cache_alloc(unionfs_dentry_cachep, GFP_ATOMIC);
-+	if (unlikely(!info))
-+		return -ENOMEM;
-+
-+	mutex_init(&info->lock);
-+	mutex_lock_nested(&info->lock, subclass);
-+
-+	info->lower_paths = NULL;
-+
-+	dentry->d_fsdata = info;
-+
-+	if (!__realloc_dentry_private_data(dentry))
-+		return 0;
-+
-+	mutex_unlock(&info->lock);
-+	free_dentry_private_data(dentry);
-+	return -ENOMEM;
-+}
-+
-+/*
-+ * scan through the lower dentry objects, and set bstart to reflect the
-+ * starting branch
-+ */
-+void update_bstart(struct dentry *dentry)
-+{
-+	int bindex;
-+	int bstart = dbstart(dentry);
-+	int bend = dbend(dentry);
-+	struct dentry *lower_dentry;
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry)
-+			continue;
-+		if (lower_dentry->d_inode) {
-+			dbstart(dentry) = bindex;
-+			break;
-+		}
-+		dput(lower_dentry);
-+		unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+	}
-+}
-+
-+
-+/*
-+ * Initialize a nameidata structure (the intent part) we can pass to a lower
-+ * file system.  Returns 0 on success or -error (only -ENOMEM possible).
-+ * Inside that nd structure, this function may also return an allocated
-+ * struct file (for open intents).  The caller, when done with this nd, must
-+ * kfree the intent file (using release_lower_nd).
-+ *
-+ * XXX: this code, and the callers of this code, should be redone using
-+ * vfs_path_lookup() when (1) the nameidata structure is refactored into a
-+ * separate intent-structure, and (2) open_namei() is broken into a VFS-only
-+ * function and a method that other file systems can call.
-+ */
-+int init_lower_nd(struct nameidata *nd, unsigned int flags)
-+{
-+	int err = 0;
-+#ifdef ALLOC_LOWER_ND_FILE
-+	/*
-+	 * XXX: one day we may need to have the lower return an open file
-+	 * for us.  It is not needed in 2.6.23-rc1 for nfs2/nfs3, but may
-+	 * very well be needed for nfs4.
-+	 */
-+	struct file *file;
-+#endif /* ALLOC_LOWER_ND_FILE */
-+
-+	memset(nd, 0, sizeof(struct nameidata));
-+	if (!flags)
-+		return err;
-+
-+	switch (flags) {
-+	case LOOKUP_CREATE:
-+		nd->intent.open.flags |= O_CREAT;
-+		/* fall through: shared code for create/open cases */
-+	case LOOKUP_OPEN:
-+		nd->flags = flags;
-+		nd->intent.open.flags |= (FMODE_READ | FMODE_WRITE);
-+#ifdef ALLOC_LOWER_ND_FILE
-+		file = kzalloc(sizeof(struct file), GFP_KERNEL);
-+		if (unlikely(!file)) {
-+			err = -ENOMEM;
-+			break; /* exit switch statement and thus return */
-+		}
-+		nd->intent.open.file = file;
-+#endif /* ALLOC_LOWER_ND_FILE */
-+		break;
-+	default:
-+		/*
-+		 * We should never get here, for now.
-+		 * We can add new cases here later on.
-+		 */
-+		pr_debug("unionfs: unknown nameidata flag 0x%x\n", flags);
-+		BUG();
-+		break;
-+	}
-+
-+	return err;
-+}
-+
-+void release_lower_nd(struct nameidata *nd, int err)
-+{
-+	if (!nd->intent.open.file)
-+		return;
-+	else if (!err)
-+		release_open_intent(nd);
-+#ifdef ALLOC_LOWER_ND_FILE
-+	kfree(nd->intent.open.file);
-+#endif /* ALLOC_LOWER_ND_FILE */
-+}
-+
-+/*
-+ * Main (and complex) driver function for Unionfs's lookup
-+ *
-+ * Returns: NULL (ok), ERR_PTR if an error occurred, or a non-null non-error
-+ * PTR if d_splice returned a different dentry.
-+ *
-+ * If lookupmode is INTERPOSE_PARTIAL/REVAL/REVAL_NEG, the passed dentry's
-+ * inode info must be locked.  If lookupmode is INTERPOSE_LOOKUP (i.e., a
-+ * newly looked-up dentry), then unionfs_lookup_backend will return a locked
-+ * dentry's info, which the caller must unlock.
-+ */
-+struct dentry *unionfs_lookup_full(struct dentry *dentry,
-+				   struct nameidata *nd_unused, int lookupmode)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry = NULL;
-+	struct vfsmount *lower_mnt;
-+	struct vfsmount *lower_dir_mnt;
-+	struct dentry *wh_lower_dentry = NULL;
-+	struct dentry *lower_dir_dentry = NULL;
-+	struct dentry *parent_dentry = NULL;
-+	struct dentry *d_interposed = NULL;
-+	int bindex, bstart, bend, bopaque;
-+	int opaque, num_positive = 0;
-+	const char *name;
-+	int namelen;
-+	int pos_start, pos_end;
-+
-+	/*
-+	 * We should already have a lock on this dentry in the case of a
-+	 * partial lookup, or a revalidation.  Otherwise it is returned from
-+	 * new_dentry_private_data already locked.
-+	 */
-+	verify_locked(dentry);
-+
-+	/* must initialize dentry operations */
-+	dentry->d_op = &unionfs_dops;
-+
-+	/* We never partial lookup the root directory. */
-+	if (IS_ROOT(dentry))
-+		goto out;
-+	parent_dentry = dget_parent(dentry);
-+
-+	name = dentry->d_name.name;
-+	namelen = dentry->d_name.len;
-+
-+	/* No dentries should get created for possible whiteout names. */
-+	if (!is_validname(name)) {
-+		err = -EPERM;
-+		goto out_free;
-+	}
-+
-+	/* Now start the actual lookup procedure. */
-+	bstart = dbstart(parent_dentry);
-+	bend = dbend(parent_dentry);
-+	bopaque = dbopaque(parent_dentry);
-+	BUG_ON(bstart < 0);
-+
-+	/* adjust bend to bopaque if needed */
-+	if ((bopaque >= 0) && (bopaque < bend))
-+		bend = bopaque;
-+
-+	/* lookup all possible dentries */
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+
-+		/* skip if we already have a positive lower dentry */
-+		if (lower_dentry) {
-+			if (dbstart(dentry) < 0)
-+				dbstart(dentry) = bindex;
-+			if (bindex > dbend(dentry))
-+				dbend(dentry) = bindex;
-+			if (lower_dentry->d_inode)
-+				num_positive++;
-+			continue;
-+		}
-+
-+		lower_dir_dentry =
-+			unionfs_lower_dentry_idx(parent_dentry, bindex);
-+		/* if the lower dentry's parent does not exist, skip this */
-+		if (!lower_dir_dentry || !lower_dir_dentry->d_inode)
-+			continue;
-+
-+		/* also skip it if the parent isn't a directory. */
-+		if (!S_ISDIR(lower_dir_dentry->d_inode->i_mode))
-+			continue; /* XXX: should be BUG_ON */
-+
-+		/* check for whiteouts: stop lookup if found */
-+		wh_lower_dentry = lookup_whiteout(name, lower_dir_dentry);
-+		if (IS_ERR(wh_lower_dentry)) {
-+			err = PTR_ERR(wh_lower_dentry);
-+			goto out_free;
-+		}
-+		if (wh_lower_dentry->d_inode) {
-+			dbend(dentry) = dbopaque(dentry) = bindex;
-+			if (dbstart(dentry) < 0)
-+				dbstart(dentry) = bindex;
-+			dput(wh_lower_dentry);
-+			break;
-+		}
-+		dput(wh_lower_dentry);
-+
-+		/* Now do regular lookup; lookup @name */
-+		lower_dir_mnt = unionfs_lower_mnt_idx(parent_dentry, bindex);
-+		lower_mnt = NULL; /* XXX: needed? */
-+
-+		lower_dentry = __lookup_one(lower_dir_dentry, lower_dir_mnt,
-+					    name, &lower_mnt);
-+
-+		if (IS_ERR(lower_dentry)) {
-+			err = PTR_ERR(lower_dentry);
-+			goto out_free;
-+		}
-+		unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
-+		BUG_ON(!lower_mnt);
-+		unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);
-+
-+		/* adjust dbstart/end */
-+		if (dbstart(dentry) < 0)
-+			dbstart(dentry) = bindex;
-+		if (bindex > dbend(dentry))
-+			dbend(dentry) = bindex;
-+		/*
-+		 * We always store the lower dentries above, and update
-+		 * dbstart/dbend, even if the whole unionfs dentry is
-+		 * negative (i.e., no lower inodes).
-+		 */
-+		if (!lower_dentry->d_inode)
-+			continue;
-+		num_positive++;
-+
-+		/*
-+		 * check if we just found an opaque directory, if so, stop
-+		 * lookups here.
-+		 */
-+		if (!S_ISDIR(lower_dentry->d_inode->i_mode))
-+			continue;
-+		opaque = is_opaque_dir(dentry, bindex);
-+		if (opaque < 0) {
-+			err = opaque;
-+			goto out_free;
-+		} else if (opaque) {
-+			dbend(dentry) = dbopaque(dentry) = bindex;
-+			break;
-+		}
-+		dbend(dentry) = bindex;
-+
-+		/* update parent directory's atime with the bindex */
-+		fsstack_copy_attr_atime(parent_dentry->d_inode,
-+					lower_dir_dentry->d_inode);
-+	}
-+
-+	/* sanity checks, then decide if to process a negative dentry */
-+	BUG_ON(dbstart(dentry) < 0 && dbend(dentry) >= 0);
-+	BUG_ON(dbstart(dentry) >= 0 && dbend(dentry) < 0);
-+
-+	if (num_positive > 0)
-+		goto out_positive;
-+
-+	/*** handle NEGATIVE dentries ***/
-+
-+	/*
-+	 * If negative, keep only first lower negative dentry, to save on
-+	 * memory.
-+	 */
-+	if (dbstart(dentry) < dbend(dentry)) {
-+		path_put_lowers(dentry, dbstart(dentry) + 1,
-+				dbend(dentry), false);
-+		dbend(dentry) = dbstart(dentry);
-+	}
-+	if (lookupmode == INTERPOSE_PARTIAL)
-+		goto out;
-+	if (lookupmode == INTERPOSE_LOOKUP) {
-+		/*
-+		 * If all we found was a whiteout in the first available
-+		 * branch, then create a negative dentry for a possibly new
-+		 * file to be created.
-+		 */
-+		if (dbopaque(dentry) < 0)
-+			goto out;
-+		/* XXX: need to get mnt here */
-+		bindex = dbstart(dentry);
-+		if (unionfs_lower_dentry_idx(dentry, bindex))
-+			goto out;
-+		lower_dir_dentry =
-+			unionfs_lower_dentry_idx(parent_dentry, bindex);
-+		if (!lower_dir_dentry || !lower_dir_dentry->d_inode)
-+			goto out;
-+		if (!S_ISDIR(lower_dir_dentry->d_inode->i_mode))
-+			goto out; /* XXX: should be BUG_ON */
-+		/* XXX: do we need to cross bind mounts here? */
-+		lower_dentry = lookup_one_len(name, lower_dir_dentry, namelen);
-+		if (IS_ERR(lower_dentry)) {
-+			err = PTR_ERR(lower_dentry);
-+			goto out;
-+		}
-+		/* XXX: need to mntget/mntput as needed too! */
-+		unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
-+		/* XXX: wrong mnt for crossing bind mounts! */
-+		lower_mnt = unionfs_mntget(dentry->d_sb->s_root, bindex);
-+		unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);
-+
-+		goto out;
-+	}
-+
-+	/* if we're revalidating a positive dentry, don't make it negative */
-+	if (lookupmode != INTERPOSE_REVAL)
-+		d_add(dentry, NULL);
-+
-+	goto out;
-+
-+out_positive:
-+	/*** handle POSITIVE dentries ***/
-+
-+	/*
-+	 * This unionfs dentry is positive (at least one lower inode
-+	 * exists), so scan entire dentry from beginning to end, and remove
-+	 * any negative lower dentries, if any.  Then, update dbstart/dbend
-+	 * to reflect the start/end of positive dentries.
-+	 */
-+	pos_start = pos_end = -1;
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry,
-+							bindex);
-+		if (lower_dentry && lower_dentry->d_inode) {
-+			if (pos_start < 0)
-+				pos_start = bindex;
-+			if (bindex > pos_end)
-+				pos_end = bindex;
-+			continue;
-+		}
-+		path_put_lowers(dentry, bindex, bindex, false);
-+	}
-+	if (pos_start >= 0)
-+		dbstart(dentry) = pos_start;
-+	if (pos_end >= 0)
-+		dbend(dentry) = pos_end;
-+
-+	/* Partial lookups need to re-interpose, or throw away older negs. */
-+	if (lookupmode == INTERPOSE_PARTIAL) {
-+		if (dentry->d_inode) {
-+			unionfs_reinterpose(dentry);
-+			goto out;
-+		}
-+
-+		/*
-+		 * This dentry was positive, so it is as if we had a
-+		 * negative revalidation.
-+		 */
-+		lookupmode = INTERPOSE_REVAL_NEG;
-+		update_bstart(dentry);
-+	}
-+
-+	/*
-+	 * Interpose can return a dentry if d_splice returned a different
-+	 * dentry.
-+	 */
-+	d_interposed = unionfs_interpose(dentry, dentry->d_sb, lookupmode);
-+	if (IS_ERR(d_interposed))
-+		err = PTR_ERR(d_interposed);
-+	else if (d_interposed)
-+		dentry = d_interposed;
-+
-+	if (!err)
-+		goto out;
-+	d_drop(dentry);
-+
-+out_free:
-+	/* should dput/mntput all the underlying dentries on error condition */
-+	if (dbstart(dentry) >= 0)
-+		path_put_lowers_all(dentry, false);
-+	/* free lower_paths unconditionally */
-+	kfree(UNIONFS_D(dentry)->lower_paths);
-+	UNIONFS_D(dentry)->lower_paths = NULL;
-+
-+out:
-+	if (dentry && UNIONFS_D(dentry)) {
-+		BUG_ON(dbstart(dentry) < 0 && dbend(dentry) >= 0);
-+		BUG_ON(dbstart(dentry) >= 0 && dbend(dentry) < 0);
-+	}
-+	if (d_interposed && UNIONFS_D(d_interposed)) {
-+		BUG_ON(dbstart(d_interposed) < 0 && dbend(d_interposed) >= 0);
-+		BUG_ON(dbstart(d_interposed) >= 0 && dbend(d_interposed) < 0);
-+	}
-+
-+	dput(parent_dentry);
-+	if (!err && d_interposed)
-+		return d_interposed;
-+	return ERR_PTR(err);
-+}
-diff --git a/fs/unionfs/main.c b/fs/unionfs/main.c
-new file mode 100644
-index 0000000..fea670b
---- /dev/null
-+++ b/fs/unionfs/main.c
-@@ -0,0 +1,777 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+#include <linux/module.h>
-+#include <linux/moduleparam.h>
-+
-+static void unionfs_fill_inode(struct dentry *dentry,
-+			       struct inode *inode)
-+{
-+	struct inode *lower_inode;
-+	struct dentry *lower_dentry;
-+	int bindex, bstart, bend;
-+
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry) {
-+			unionfs_set_lower_inode_idx(inode, bindex, NULL);
-+			continue;
-+		}
-+
-+		/* Initialize the lower inode to the new lower inode. */
-+		if (!lower_dentry->d_inode)
-+			continue;
-+
-+		unionfs_set_lower_inode_idx(inode, bindex,
-+					    igrab(lower_dentry->d_inode));
-+	}
-+
-+	ibstart(inode) = dbstart(dentry);
-+	ibend(inode) = dbend(dentry);
-+
-+	/* Use attributes from the first branch. */
-+	lower_inode = unionfs_lower_inode(inode);
-+
-+	/* Use different set of inode ops for symlinks & directories */
-+	if (S_ISLNK(lower_inode->i_mode))
-+		inode->i_op = &unionfs_symlink_iops;
-+	else if (S_ISDIR(lower_inode->i_mode))
-+		inode->i_op = &unionfs_dir_iops;
-+
-+	/* Use different set of file ops for directories */
-+	if (S_ISDIR(lower_inode->i_mode))
-+		inode->i_fop = &unionfs_dir_fops;
-+
-+	/* properly initialize special inodes */
-+	if (S_ISBLK(lower_inode->i_mode) || S_ISCHR(lower_inode->i_mode) ||
-+	    S_ISFIFO(lower_inode->i_mode) || S_ISSOCK(lower_inode->i_mode))
-+		init_special_inode(inode, lower_inode->i_mode,
-+				   lower_inode->i_rdev);
-+
-+	/* all well, copy inode attributes */
-+	unionfs_copy_attr_all(inode, lower_inode);
-+	fsstack_copy_inode_size(inode, lower_inode);
-+}
-+
-+/*
-+ * Connect a unionfs inode dentry/inode with several lower ones.  This is
-+ * the classic stackable file system "vnode interposition" action.
-+ *
-+ * @sb: unionfs's super_block
-+ */
-+struct dentry *unionfs_interpose(struct dentry *dentry, struct super_block *sb,
-+				 int flag)
-+{
-+	int err = 0;
-+	struct inode *inode;
-+	int need_fill_inode = 1;
-+	struct dentry *spliced = NULL;
-+
-+	verify_locked(dentry);
-+
-+	/*
-+	 * We allocate our new inode below by calling unionfs_iget,
-+	 * which will initialize some of the new inode's fields
-+	 */
-+
-+	/*
-+	 * On revalidate we've already got our own inode and just need
-+	 * to fix it up.
-+	 */
-+	if (flag == INTERPOSE_REVAL) {
-+		inode = dentry->d_inode;
-+		UNIONFS_I(inode)->bstart = -1;
-+		UNIONFS_I(inode)->bend = -1;
-+		atomic_set(&UNIONFS_I(inode)->generation,
-+			   atomic_read(&UNIONFS_SB(sb)->generation));
-+
-+		UNIONFS_I(inode)->lower_inodes =
-+			kcalloc(sbmax(sb), sizeof(struct inode *), GFP_KERNEL);
-+		if (unlikely(!UNIONFS_I(inode)->lower_inodes)) {
-+			err = -ENOMEM;
-+			goto out;
-+		}
-+	} else {
-+		/* get unique inode number for unionfs */
-+		inode = unionfs_iget(sb, iunique(sb, UNIONFS_ROOT_INO));
-+		if (IS_ERR(inode)) {
-+			err = PTR_ERR(inode);
-+			goto out;
-+		}
-+		if (atomic_read(&inode->i_count) > 1)
-+			goto skip;
-+	}
-+
-+	need_fill_inode = 0;
-+	unionfs_fill_inode(dentry, inode);
-+
-+skip:
-+	/* only (our) lookup wants to do a d_add */
-+	switch (flag) {
-+	case INTERPOSE_DEFAULT:
-+		/* for operations which create new inodes */
-+		d_add(dentry, inode);
-+		break;
-+	case INTERPOSE_REVAL_NEG:
-+		d_instantiate(dentry, inode);
-+		break;
-+	case INTERPOSE_LOOKUP:
-+		spliced = d_splice_alias(inode, dentry);
-+		if (spliced && spliced != dentry) {
-+			/*
-+			 * d_splice can return a dentry if it was
-+			 * disconnected and had to be moved.  We must ensure
-+			 * that the private data of the new dentry is
-+			 * correct and that the inode info was filled
-+			 * properly.  Finally we must return this new
-+			 * dentry.
-+			 */
-+			spliced->d_op = &unionfs_dops;
-+			spliced->d_fsdata = dentry->d_fsdata;
-+			dentry->d_fsdata = NULL;
-+			dentry = spliced;
-+			if (need_fill_inode) {
-+				need_fill_inode = 0;
-+				unionfs_fill_inode(dentry, inode);
-+			}
-+			goto out_spliced;
-+		} else if (!spliced) {
-+			if (need_fill_inode) {
-+				need_fill_inode = 0;
-+				unionfs_fill_inode(dentry, inode);
-+				goto out_spliced;
-+			}
-+		}
-+		break;
-+	case INTERPOSE_REVAL:
-+		/* Do nothing. */
-+		break;
-+	default:
-+		printk(KERN_CRIT "unionfs: invalid interpose flag passed!\n");
-+		BUG();
-+	}
-+	goto out;
-+
-+out_spliced:
-+	if (!err)
-+		return spliced;
-+out:
-+	return ERR_PTR(err);
-+}
-+
-+/* like interpose above, but for an already existing dentry */
-+void unionfs_reinterpose(struct dentry *dentry)
-+{
-+	struct dentry *lower_dentry;
-+	struct inode *inode;
-+	int bindex, bstart, bend;
-+
-+	verify_locked(dentry);
-+
-+	/* This is pre-allocated inode */
-+	inode = dentry->d_inode;
-+
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry)
-+			continue;
-+
-+		if (!lower_dentry->d_inode)
-+			continue;
-+		if (unionfs_lower_inode_idx(inode, bindex))
-+			continue;
-+		unionfs_set_lower_inode_idx(inode, bindex,
-+					    igrab(lower_dentry->d_inode));
-+	}
-+	ibstart(inode) = dbstart(dentry);
-+	ibend(inode) = dbend(dentry);
-+}
-+
-+/*
-+ * make sure the branch we just looked up (nd) makes sense:
-+ *
-+ * 1) we're not trying to stack unionfs on top of unionfs
-+ * 2) it exists
-+ * 3) is a directory
-+ */
-+int check_branch(struct nameidata *nd)
-+{
-+	/* XXX: remove in ODF code -- stacking unions allowed there */
-+	if (!strcmp(nd->path.dentry->d_sb->s_type->name, UNIONFS_NAME))
-+		return -EINVAL;
-+	if (!nd->path.dentry->d_inode)
-+		return -ENOENT;
-+	if (!S_ISDIR(nd->path.dentry->d_inode->i_mode))
-+		return -ENOTDIR;
-+	return 0;
-+}
-+
-+/* checks if two lower_dentries have overlapping branches */
-+static int is_branch_overlap(struct dentry *dent1, struct dentry *dent2)
-+{
-+	struct dentry *dent = NULL;
-+
-+	dent = dent1;
-+	while ((dent != dent2) && (dent->d_parent != dent))
-+		dent = dent->d_parent;
-+
-+	if (dent == dent2)
-+		return 1;
-+
-+	dent = dent2;
-+	while ((dent != dent1) && (dent->d_parent != dent))
-+		dent = dent->d_parent;
-+
-+	return (dent == dent1);
-+}
-+
-+/*
-+ * Parse "ro" or "rw" options, but default to "rw" if no mode options was
-+ * specified.  Fill the mode bits in @perms.  If encounter an unknown
-+ * string, return -EINVAL.  Otherwise return 0.
-+ */
-+int parse_branch_mode(const char *name, int *perms)
-+{
-+	if (!name || !strcmp(name, "rw")) {
-+		*perms = MAY_READ | MAY_WRITE;
-+		return 0;
-+	}
-+	if (!strcmp(name, "ro")) {
-+		*perms = MAY_READ;
-+		return 0;
-+	}
-+	return -EINVAL;
-+}
-+
-+/*
-+ * parse the dirs= mount argument
-+ *
-+ * We don't need to lock the superblock private data's rwsem, as we get
-+ * called only by unionfs_read_super - it is still a long time before anyone
-+ * can even get a reference to us.
-+ */
-+static int parse_dirs_option(struct super_block *sb, struct unionfs_dentry_info
-+			     *lower_root_info, char *options)
-+{
-+	struct nameidata nd;
-+	char *name;
-+	int err = 0;
-+	int branches = 1;
-+	int bindex = 0;
-+	int i = 0;
-+	int j = 0;
-+	struct dentry *dent1;
-+	struct dentry *dent2;
-+
-+	if (options[0] == '\0') {
-+		printk(KERN_ERR "unionfs: no branches specified\n");
-+		err = -EINVAL;
-+		goto out;
-+	}
-+
-+	/*
-+	 * Each colon means we have a separator, this is really just a rough
-+	 * guess, since strsep will handle empty fields for us.
-+	 */
-+	for (i = 0; options[i]; i++)
-+		if (options[i] == ':')
-+			branches++;
-+
-+	/* allocate space for underlying pointers to lower dentry */
-+	UNIONFS_SB(sb)->data =
-+		kcalloc(branches, sizeof(struct unionfs_data), GFP_KERNEL);
-+	if (unlikely(!UNIONFS_SB(sb)->data)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+
-+	lower_root_info->lower_paths =
-+		kcalloc(branches, sizeof(struct path), GFP_KERNEL);
-+	if (unlikely(!lower_root_info->lower_paths)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+
-+	/* now parsing a string such as "b1:b2=rw:b3=ro:b4" */
-+	branches = 0;
-+	while ((name = strsep(&options, ":")) != NULL) {
-+		int perms;
-+		char *mode = strchr(name, '=');
-+
-+		if (!name)
-+			continue;
-+		if (!*name) {	/* bad use of ':' (extra colons) */
-+			err = -EINVAL;
-+			goto out;
-+		}
-+
-+		branches++;
-+
-+		/* strip off '=' if any */
-+		if (mode)
-+			*mode++ = '\0';
-+
-+		err = parse_branch_mode(mode, &perms);
-+		if (err) {
-+			printk(KERN_ERR "unionfs: invalid mode \"%s\" for "
-+			       "branch %d\n", mode, bindex);
-+			goto out;
-+		}
-+		/* ensure that leftmost branch is writeable */
-+		if (!bindex && !(perms & MAY_WRITE)) {
-+			printk(KERN_ERR "unionfs: leftmost branch cannot be "
-+			       "read-only (use \"-o ro\" to create a "
-+			       "read-only union)\n");
-+			err = -EINVAL;
-+			goto out;
-+		}
-+
-+		err = path_lookup(name, LOOKUP_FOLLOW, &nd);
-+		if (err) {
-+			printk(KERN_ERR "unionfs: error accessing "
-+			       "lower directory '%s' (error %d)\n",
-+			       name, err);
-+			goto out;
-+		}
-+
-+		err = check_branch(&nd);
-+		if (err) {
-+			printk(KERN_ERR "unionfs: lower directory "
-+			       "'%s' is not a valid branch\n", name);
-+			path_put(&nd.path);
-+			goto out;
-+		}
-+
-+		lower_root_info->lower_paths[bindex].dentry = nd.path.dentry;
-+		lower_root_info->lower_paths[bindex].mnt = nd.path.mnt;
-+
-+		set_branchperms(sb, bindex, perms);
-+		set_branch_count(sb, bindex, 0);
-+		new_branch_id(sb, bindex);
-+
-+		if (lower_root_info->bstart < 0)
-+			lower_root_info->bstart = bindex;
-+		lower_root_info->bend = bindex;
-+		bindex++;
-+	}
-+
-+	if (branches == 0) {
-+		printk(KERN_ERR "unionfs: no branches specified\n");
-+		err = -EINVAL;
-+		goto out;
-+	}
-+
-+	BUG_ON(branches != (lower_root_info->bend + 1));
-+
-+	/*
-+	 * Ensure that no overlaps exist in the branches.
-+	 *
-+	 * This test is required because the Linux kernel has no support
-+	 * currently for ensuring coherency between stackable layers and
-+	 * branches.  If we were to allow overlapping branches, it would be
-+	 * possible, for example, to delete a file via one branch, which
-+	 * would not be reflected in another branch.  Such incoherency could
-+	 * lead to inconsistencies and even kernel oopses.  Rather than
-+	 * implement hacks to work around some of these cache-coherency
-+	 * problems, we prevent branch overlapping, for now.  A complete
-+	 * solution will involve proper kernel/VFS support for cache
-+	 * coherency, at which time we could safely remove this
-+	 * branch-overlapping test.
-+	 */
-+	for (i = 0; i < branches; i++) {
-+		dent1 = lower_root_info->lower_paths[i].dentry;
-+		for (j = i + 1; j < branches; j++) {
-+			dent2 = lower_root_info->lower_paths[j].dentry;
-+			if (is_branch_overlap(dent1, dent2)) {
-+				printk(KERN_ERR "unionfs: branches %d and "
-+				       "%d overlap\n", i, j);
-+				err = -EINVAL;
-+				goto out;
-+			}
-+		}
-+	}
-+
-+out:
-+	if (err) {
-+		for (i = 0; i < branches; i++)
-+			if (lower_root_info->lower_paths[i].dentry) {
-+				dput(lower_root_info->lower_paths[i].dentry);
-+				/* initialize: can't use unionfs_mntput here */
-+				mntput(lower_root_info->lower_paths[i].mnt);
-+			}
-+
-+		kfree(lower_root_info->lower_paths);
-+		kfree(UNIONFS_SB(sb)->data);
-+
-+		/*
-+		 * MUST clear the pointers to prevent potential double free if
-+		 * the caller dies later on
-+		 */
-+		lower_root_info->lower_paths = NULL;
-+		UNIONFS_SB(sb)->data = NULL;
-+	}
-+	return err;
-+}
-+
-+/*
-+ * Parse mount options.  See the manual page for usage instructions.
-+ *
-+ * Returns the dentry object of the lower-level (lower) directory;
-+ * We want to mount our stackable file system on top of that lower directory.
-+ */
-+static struct unionfs_dentry_info *unionfs_parse_options(
-+					 struct super_block *sb,
-+					 char *options)
-+{
-+	struct unionfs_dentry_info *lower_root_info;
-+	char *optname;
-+	int err = 0;
-+	int bindex;
-+	int dirsfound = 0;
-+
-+	/* allocate private data area */
-+	err = -ENOMEM;
-+	lower_root_info =
-+		kzalloc(sizeof(struct unionfs_dentry_info), GFP_KERNEL);
-+	if (unlikely(!lower_root_info))
-+		goto out_error;
-+	lower_root_info->bstart = -1;
-+	lower_root_info->bend = -1;
-+	lower_root_info->bopaque = -1;
-+
-+	while ((optname = strsep(&options, ",")) != NULL) {
-+		char *optarg;
-+
-+		if (!optname || !*optname)
-+			continue;
-+
-+		optarg = strchr(optname, '=');
-+		if (optarg)
-+			*optarg++ = '\0';
-+
-+		/*
-+		 * All of our options take an argument now. Insert ones that
-+		 * don't, above this check.
-+		 */
-+		if (!optarg) {
-+			printk(KERN_ERR "unionfs: %s requires an argument\n",
-+			       optname);
-+			err = -EINVAL;
-+			goto out_error;
-+		}
-+
-+		if (!strcmp("dirs", optname)) {
-+			if (++dirsfound > 1) {
-+				printk(KERN_ERR
-+				       "unionfs: multiple dirs specified\n");
-+				err = -EINVAL;
-+				goto out_error;
-+			}
-+			err = parse_dirs_option(sb, lower_root_info, optarg);
-+			if (err)
-+				goto out_error;
-+			continue;
-+		}
-+
-+		err = -EINVAL;
-+		printk(KERN_ERR
-+		       "unionfs: unrecognized option '%s'\n", optname);
-+		goto out_error;
-+	}
-+	if (dirsfound != 1) {
-+		printk(KERN_ERR "unionfs: dirs option required\n");
-+		err = -EINVAL;
-+		goto out_error;
-+	}
-+	goto out;
-+
-+out_error:
-+	if (lower_root_info && lower_root_info->lower_paths) {
-+		for (bindex = lower_root_info->bstart;
-+		     bindex >= 0 && bindex <= lower_root_info->bend;
-+		     bindex++) {
-+			struct dentry *d;
-+			struct vfsmount *m;
-+
-+			d = lower_root_info->lower_paths[bindex].dentry;
-+			m = lower_root_info->lower_paths[bindex].mnt;
-+
-+			dput(d);
-+			/* initializing: can't use unionfs_mntput here */
-+			mntput(m);
-+		}
-+	}
-+
-+	kfree(lower_root_info->lower_paths);
-+	kfree(lower_root_info);
-+
-+	kfree(UNIONFS_SB(sb)->data);
-+	UNIONFS_SB(sb)->data = NULL;
-+
-+	lower_root_info = ERR_PTR(err);
-+out:
-+	return lower_root_info;
-+}
-+
-+/*
-+ * our custom d_alloc_root work-alike
-+ *
-+ * we can't use d_alloc_root if we want to use our own interpose function
-+ * unchanged, so we simply call our own "fake" d_alloc_root
-+ */
-+static struct dentry *unionfs_d_alloc_root(struct super_block *sb)
-+{
-+	struct dentry *ret = NULL;
-+
-+	if (sb) {
-+		static const struct qstr name = {
-+			.name = "/",
-+			.len = 1
-+		};
-+
-+		ret = d_alloc(NULL, &name);
-+		if (likely(ret)) {
-+			ret->d_op = &unionfs_dops;
-+			ret->d_sb = sb;
-+			ret->d_parent = ret;
-+		}
-+	}
-+	return ret;
-+}
-+
-+/*
-+ * There is no need to lock the unionfs_super_info's rwsem as there is no
-+ * way anyone can have a reference to the superblock at this point in time.
-+ */
-+static int unionfs_read_super(struct super_block *sb, void *raw_data,
-+			      int silent)
-+{
-+	int err = 0;
-+	struct unionfs_dentry_info *lower_root_info = NULL;
-+	int bindex, bstart, bend;
-+
-+	if (!raw_data) {
-+		printk(KERN_ERR
-+		       "unionfs: read_super: missing data argument\n");
-+		err = -EINVAL;
-+		goto out;
-+	}
-+
-+	/* Allocate superblock private data */
-+	sb->s_fs_info = kzalloc(sizeof(struct unionfs_sb_info), GFP_KERNEL);
-+	if (unlikely(!UNIONFS_SB(sb))) {
-+		printk(KERN_CRIT "unionfs: read_super: out of memory\n");
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+
-+	UNIONFS_SB(sb)->bend = -1;
-+	atomic_set(&UNIONFS_SB(sb)->generation, 1);
-+	init_rwsem(&UNIONFS_SB(sb)->rwsem);
-+	UNIONFS_SB(sb)->high_branch_id = -1; /* -1 == invalid branch ID */
-+
-+	lower_root_info = unionfs_parse_options(sb, raw_data);
-+	if (IS_ERR(lower_root_info)) {
-+		printk(KERN_ERR
-+		       "unionfs: read_super: error while parsing options "
-+		       "(err = %ld)\n", PTR_ERR(lower_root_info));
-+		err = PTR_ERR(lower_root_info);
-+		lower_root_info = NULL;
-+		goto out_free;
-+	}
-+	if (lower_root_info->bstart == -1) {
-+		err = -ENOENT;
-+		goto out_free;
-+	}
-+
-+	/* set the lower superblock field of upper superblock */
-+	bstart = lower_root_info->bstart;
-+	BUG_ON(bstart != 0);
-+	sbend(sb) = bend = lower_root_info->bend;
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		struct dentry *d = lower_root_info->lower_paths[bindex].dentry;
-+		atomic_inc(&d->d_sb->s_active);
-+		unionfs_set_lower_super_idx(sb, bindex, d->d_sb);
-+	}
-+
-+	/* max Bytes is the maximum bytes from highest priority branch */
-+	sb->s_maxbytes = unionfs_lower_super_idx(sb, 0)->s_maxbytes;
-+
-+	/*
-+	 * Our c/m/atime granularity is 1 ns because we may stack on file
-+	 * systems whose granularity is as good.  This is important for our
-+	 * time-based cache coherency.
-+	 */
-+	sb->s_time_gran = 1;
-+
-+	sb->s_op = &unionfs_sops;
-+
-+	/* See comment next to the definition of unionfs_d_alloc_root */
-+	sb->s_root = unionfs_d_alloc_root(sb);
-+	if (unlikely(!sb->s_root)) {
-+		err = -ENOMEM;
-+		goto out_dput;
-+	}
-+
-+	/* link the upper and lower dentries */
-+	sb->s_root->d_fsdata = NULL;
-+	err = new_dentry_private_data(sb->s_root, UNIONFS_DMUTEX_ROOT);
-+	if (unlikely(err))
-+		goto out_freedpd;
-+
-+	/* Set the lower dentries for s_root */
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		struct dentry *d;
-+		struct vfsmount *m;
-+
-+		d = lower_root_info->lower_paths[bindex].dentry;
-+		m = lower_root_info->lower_paths[bindex].mnt;
-+
-+		unionfs_set_lower_dentry_idx(sb->s_root, bindex, d);
-+		unionfs_set_lower_mnt_idx(sb->s_root, bindex, m);
-+	}
-+	dbstart(sb->s_root) = bstart;
-+	dbend(sb->s_root) = bend;
-+
-+	/* Set the generation number to one, since this is for the mount. */
-+	atomic_set(&UNIONFS_D(sb->s_root)->generation, 1);
-+
-+	/*
-+	 * Call interpose to create the upper level inode.  Only
-+	 * INTERPOSE_LOOKUP can return a value other than 0 on err.
-+	 */
-+	err = PTR_ERR(unionfs_interpose(sb->s_root, sb, 0));
-+	unionfs_unlock_dentry(sb->s_root);
-+	if (!err)
-+		goto out;
-+	/* else fall through */
-+
-+out_freedpd:
-+	if (UNIONFS_D(sb->s_root)) {
-+		kfree(UNIONFS_D(sb->s_root)->lower_paths);
-+		free_dentry_private_data(sb->s_root);
-+	}
-+	dput(sb->s_root);
-+
-+out_dput:
-+	if (lower_root_info && !IS_ERR(lower_root_info)) {
-+		for (bindex = lower_root_info->bstart;
-+		     bindex <= lower_root_info->bend; bindex++) {
-+			struct dentry *d;
-+			struct vfsmount *m;
-+
-+			d = lower_root_info->lower_paths[bindex].dentry;
-+			m = lower_root_info->lower_paths[bindex].mnt;
-+
-+			dput(d);
-+			/* initializing: can't use unionfs_mntput here */
-+			mntput(m);
-+			/* drop refs we took earlier */
-+			atomic_dec(&d->d_sb->s_active);
-+		}
-+		kfree(lower_root_info->lower_paths);
-+		kfree(lower_root_info);
-+		lower_root_info = NULL;
-+	}
-+
-+out_free:
-+	kfree(UNIONFS_SB(sb)->data);
-+	kfree(UNIONFS_SB(sb));
-+	sb->s_fs_info = NULL;
-+
-+out:
-+	if (lower_root_info && !IS_ERR(lower_root_info)) {
-+		kfree(lower_root_info->lower_paths);
-+		kfree(lower_root_info);
-+	}
-+	return err;
-+}
-+
-+static int unionfs_get_sb(struct file_system_type *fs_type,
-+			  int flags, const char *dev_name,
-+			  void *raw_data, struct vfsmount *mnt)
-+{
-+	int err;
-+	err = get_sb_nodev(fs_type, flags, raw_data, unionfs_read_super, mnt);
-+	if (!err)
-+		UNIONFS_SB(mnt->mnt_sb)->dev_name =
-+			kstrdup(dev_name, GFP_KERNEL);
-+	return err;
-+}
-+
-+static struct file_system_type unionfs_fs_type = {
-+	.owner		= THIS_MODULE,
-+	.name		= UNIONFS_NAME,
-+	.get_sb		= unionfs_get_sb,
-+	.kill_sb	= generic_shutdown_super,
-+	.fs_flags	= FS_REVAL_DOT,
-+};
-+
-+static int __init init_unionfs_fs(void)
-+{
-+	int err;
-+
-+	pr_info("Registering unionfs " UNIONFS_VERSION "\n");
-+
-+	err = unionfs_init_filldir_cache();
-+	if (unlikely(err))
-+		goto out;
-+	err = unionfs_init_inode_cache();
-+	if (unlikely(err))
-+		goto out;
-+	err = unionfs_init_dentry_cache();
-+	if (unlikely(err))
-+		goto out;
-+	err = init_sioq();
-+	if (unlikely(err))
-+		goto out;
-+	err = register_filesystem(&unionfs_fs_type);
-+out:
-+	if (unlikely(err)) {
-+		stop_sioq();
-+		unionfs_destroy_filldir_cache();
-+		unionfs_destroy_inode_cache();
-+		unionfs_destroy_dentry_cache();
-+	}
-+	return err;
-+}
-+
-+static void __exit exit_unionfs_fs(void)
-+{
-+	stop_sioq();
-+	unionfs_destroy_filldir_cache();
-+	unionfs_destroy_inode_cache();
-+	unionfs_destroy_dentry_cache();
-+	unregister_filesystem(&unionfs_fs_type);
-+	pr_info("Completed unionfs module unload\n");
-+}
-+
-+MODULE_AUTHOR("Erez Zadok, Filesystems and Storage Lab, Stony Brook University"
-+	      " (http://www.fsl.cs.sunysb.edu)");
-+MODULE_DESCRIPTION("Unionfs " UNIONFS_VERSION
-+		   " (http://unionfs.filesystems.org)");
-+MODULE_LICENSE("GPL");
-+
-+module_init(init_unionfs_fs);
-+module_exit(exit_unionfs_fs);
-diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
-new file mode 100644
-index 0000000..b7d4713
---- /dev/null
-+++ b/fs/unionfs/mmap.c
-@@ -0,0 +1,89 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2006      Shaya Potter
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+
-+/*
-+ * XXX: we need a dummy readpage handler because generic_file_mmap (which we
-+ * use in unionfs_mmap) checks for the existence of
-+ * mapping->a_ops->readpage, else it returns -ENOEXEC.  The VFS will need to
-+ * be fixed to allow a file system to define vm_ops->fault without any
-+ * address_space_ops whatsoever.
-+ *
-+ * Otherwise, we don't want to use our readpage method at all.
-+ */
-+static int unionfs_readpage(struct file *file, struct page *page)
-+{
-+	BUG();
-+	return -EINVAL;
-+}
-+
-+static int unionfs_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-+{
-+	int err;
-+	struct file *file, *lower_file;
-+	struct vm_operations_struct *lower_vm_ops;
-+	struct vm_area_struct lower_vma;
-+
-+	BUG_ON(!vma);
-+	memcpy(&lower_vma, vma, sizeof(struct vm_area_struct));
-+	file = lower_vma.vm_file;
-+	lower_vm_ops = UNIONFS_F(file)->lower_vm_ops;
-+	BUG_ON(!lower_vm_ops);
-+
-+	lower_file = unionfs_lower_file(file);
-+	BUG_ON(!lower_file);
-+	/*
-+	 * XXX: vm_ops->fault may be called in parallel.  Because we have to
-+	 * resort to temporarily changing the vma->vm_file to point to the
-+	 * lower file, a concurrent invocation of unionfs_fault could see a
-+	 * different value.  In this workaround, we keep a different copy of
-+	 * the vma structure in our stack, so we never expose a different
-+	 * value of the vma->vm_file called to us, even temporarily.  A
-+	 * better fix would be to change the calling semantics of ->fault to
-+	 * take an explicit file pointer.
-+	 */
-+	lower_vma.vm_file = lower_file;
-+	err = lower_vm_ops->fault(&lower_vma, vmf);
-+	return err;
-+}
-+
-+/*
-+ * XXX: the default address_space_ops for unionfs is empty.  We cannot set
-+ * our inode->i_mapping->a_ops to NULL because too many code paths expect
-+ * the a_ops vector to be non-NULL.
-+ */
-+struct address_space_operations unionfs_aops = {
-+	/* empty on purpose */
-+};
-+
-+/*
-+ * XXX: we need a second, dummy address_space_ops vector, to be used
-+ * temporarily during unionfs_mmap, because the latter calls
-+ * generic_file_mmap, which checks if ->readpage exists, else returns
-+ * -ENOEXEC.
-+ */
-+struct address_space_operations unionfs_dummy_aops = {
-+	.readpage	= unionfs_readpage,
-+};
-+
-+struct vm_operations_struct unionfs_vm_ops = {
-+	.fault		= unionfs_fault,
-+};
-diff --git a/fs/unionfs/rdstate.c b/fs/unionfs/rdstate.c
-new file mode 100644
-index 0000000..06d5374
---- /dev/null
-+++ b/fs/unionfs/rdstate.c
-@@ -0,0 +1,285 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/* This file contains the routines for maintaining readdir state. */
-+
-+/*
-+ * There are two structures here, rdstate which is a hash table
-+ * of the second structure which is a filldir_node.
-+ */
-+
-+/*
-+ * This is a struct kmem_cache for filldir nodes, because we allocate a lot
-+ * of them and they shouldn't waste memory.  If the node has a small name
-+ * (as defined by the dentry structure), then we use an inline name to
-+ * preserve kmalloc space.
-+ */
-+static struct kmem_cache *unionfs_filldir_cachep;
-+
-+int unionfs_init_filldir_cache(void)
-+{
-+	unionfs_filldir_cachep =
-+		kmem_cache_create("unionfs_filldir",
-+				  sizeof(struct filldir_node), 0,
-+				  SLAB_RECLAIM_ACCOUNT, NULL);
-+
-+	return (unionfs_filldir_cachep ? 0 : -ENOMEM);
-+}
-+
-+void unionfs_destroy_filldir_cache(void)
-+{
-+	if (unionfs_filldir_cachep)
-+		kmem_cache_destroy(unionfs_filldir_cachep);
-+}
-+
-+/*
-+ * This is a tuning parameter that tells us roughly how big to make the
-+ * hash table in directory entries per page.  This isn't perfect, but
-+ * at least we get a hash table size that shouldn't be too overloaded.
-+ * The following averages are based on my home directory.
-+ * 14.44693	Overall
-+ * 12.29	Single Page Directories
-+ * 117.93	Multi-page directories
-+ */
-+#define DENTPAGE 4096
-+#define DENTPERONEPAGE 12
-+#define DENTPERPAGE 118
-+#define MINHASHSIZE 1
-+static int guesstimate_hash_size(struct inode *inode)
-+{
-+	struct inode *lower_inode;
-+	int bindex;
-+	int hashsize = MINHASHSIZE;
-+
-+	if (UNIONFS_I(inode)->hashsize > 0)
-+		return UNIONFS_I(inode)->hashsize;
-+
-+	for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
-+		lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+		if (!lower_inode)
-+			continue;
-+
-+		if (i_size_read(lower_inode) == DENTPAGE)
-+			hashsize += DENTPERONEPAGE;
-+		else
-+			hashsize += (i_size_read(lower_inode) / DENTPAGE) *
-+				DENTPERPAGE;
-+	}
-+
-+	return hashsize;
-+}
-+
-+int init_rdstate(struct file *file)
-+{
-+	BUG_ON(sizeof(loff_t) !=
-+	       (sizeof(unsigned int) + sizeof(unsigned int)));
-+	BUG_ON(UNIONFS_F(file)->rdstate != NULL);
-+
-+	UNIONFS_F(file)->rdstate = alloc_rdstate(file->f_path.dentry->d_inode,
-+						 fbstart(file));
-+
-+	return (UNIONFS_F(file)->rdstate ? 0 : -ENOMEM);
-+}
-+
-+struct unionfs_dir_state *find_rdstate(struct inode *inode, loff_t fpos)
-+{
-+	struct unionfs_dir_state *rdstate = NULL;
-+	struct list_head *pos;
-+
-+	spin_lock(&UNIONFS_I(inode)->rdlock);
-+	list_for_each(pos, &UNIONFS_I(inode)->readdircache) {
-+		struct unionfs_dir_state *r =
-+			list_entry(pos, struct unionfs_dir_state, cache);
-+		if (fpos == rdstate2offset(r)) {
-+			UNIONFS_I(inode)->rdcount--;
-+			list_del(&r->cache);
-+			rdstate = r;
-+			break;
-+		}
-+	}
-+	spin_unlock(&UNIONFS_I(inode)->rdlock);
-+	return rdstate;
-+}
-+
-+struct unionfs_dir_state *alloc_rdstate(struct inode *inode, int bindex)
-+{
-+	int i = 0;
-+	int hashsize;
-+	unsigned long mallocsize = sizeof(struct unionfs_dir_state);
-+	struct unionfs_dir_state *rdstate;
-+
-+	hashsize = guesstimate_hash_size(inode);
-+	mallocsize += hashsize * sizeof(struct list_head);
-+	mallocsize = __roundup_pow_of_two(mallocsize);
-+
-+	/* This should give us about 500 entries anyway. */
-+	if (mallocsize > PAGE_SIZE)
-+		mallocsize = PAGE_SIZE;
-+
-+	hashsize = (mallocsize - sizeof(struct unionfs_dir_state)) /
-+		sizeof(struct list_head);
-+
-+	rdstate = kmalloc(mallocsize, GFP_KERNEL);
-+	if (unlikely(!rdstate))
-+		return NULL;
-+
-+	spin_lock(&UNIONFS_I(inode)->rdlock);
-+	if (UNIONFS_I(inode)->cookie >= (MAXRDCOOKIE - 1))
-+		UNIONFS_I(inode)->cookie = 1;
-+	else
-+		UNIONFS_I(inode)->cookie++;
-+
-+	rdstate->cookie = UNIONFS_I(inode)->cookie;
-+	spin_unlock(&UNIONFS_I(inode)->rdlock);
-+	rdstate->offset = 1;
-+	rdstate->access = jiffies;
-+	rdstate->bindex = bindex;
-+	rdstate->dirpos = 0;
-+	rdstate->hashentries = 0;
-+	rdstate->size = hashsize;
-+	for (i = 0; i < rdstate->size; i++)
-+		INIT_LIST_HEAD(&rdstate->list[i]);
-+
-+	return rdstate;
-+}
-+
-+static void free_filldir_node(struct filldir_node *node)
-+{
-+	if (node->namelen >= DNAME_INLINE_LEN_MIN)
-+		kfree(node->name);
-+	kmem_cache_free(unionfs_filldir_cachep, node);
-+}
-+
-+void free_rdstate(struct unionfs_dir_state *state)
-+{
-+	struct filldir_node *tmp;
-+	int i;
-+
-+	for (i = 0; i < state->size; i++) {
-+		struct list_head *head = &(state->list[i]);
-+		struct list_head *pos, *n;
-+
-+		/* traverse the list and deallocate space */
-+		list_for_each_safe(pos, n, head) {
-+			tmp = list_entry(pos, struct filldir_node, file_list);
-+			list_del(&tmp->file_list);
-+			free_filldir_node(tmp);
-+		}
-+	}
-+
-+	kfree(state);
-+}
-+
-+struct filldir_node *find_filldir_node(struct unionfs_dir_state *rdstate,
-+				       const char *name, int namelen,
-+				       int is_whiteout)
-+{
-+	int index;
-+	unsigned int hash;
-+	struct list_head *head;
-+	struct list_head *pos;
-+	struct filldir_node *cursor = NULL;
-+	int found = 0;
-+
-+	BUG_ON(namelen <= 0);
-+
-+	hash = full_name_hash(name, namelen);
-+	index = hash % rdstate->size;
-+
-+	head = &(rdstate->list[index]);
-+	list_for_each(pos, head) {
-+		cursor = list_entry(pos, struct filldir_node, file_list);
-+
-+		if (cursor->namelen == namelen && cursor->hash == hash &&
-+		    !strncmp(cursor->name, name, namelen)) {
-+			/*
-+			 * a duplicate exists, and hence no need to create
-+			 * entry to the list
-+			 */
-+			found = 1;
-+
-+			/*
-+			 * if a duplicate is found in this branch, and is
-+			 * not due to the caller looking for an entry to
-+			 * whiteout, then the file system may be corrupted.
-+			 */
-+			if (unlikely(!is_whiteout &&
-+				     cursor->bindex == rdstate->bindex))
-+				printk(KERN_ERR "unionfs: filldir: possible "
-+				       "I/O error: a file is duplicated "
-+				       "in the same branch %d: %s\n",
-+				       rdstate->bindex, cursor->name);
-+			break;
-+		}
-+	}
-+
-+	if (!found)
-+		cursor = NULL;
-+
-+	return cursor;
-+}
-+
-+int add_filldir_node(struct unionfs_dir_state *rdstate, const char *name,
-+		     int namelen, int bindex, int whiteout)
-+{
-+	struct filldir_node *new;
-+	unsigned int hash;
-+	int index;
-+	int err = 0;
-+	struct list_head *head;
-+
-+	BUG_ON(namelen <= 0);
-+
-+	hash = full_name_hash(name, namelen);
-+	index = hash % rdstate->size;
-+	head = &(rdstate->list[index]);
-+
-+	new = kmem_cache_alloc(unionfs_filldir_cachep, GFP_KERNEL);
-+	if (unlikely(!new)) {
-+		err = -ENOMEM;
-+		goto out;
-+	}
-+
-+	INIT_LIST_HEAD(&new->file_list);
-+	new->namelen = namelen;
-+	new->hash = hash;
-+	new->bindex = bindex;
-+	new->whiteout = whiteout;
-+
-+	if (namelen < DNAME_INLINE_LEN_MIN) {
-+		new->name = new->iname;
-+	} else {
-+		new->name = kmalloc(namelen + 1, GFP_KERNEL);
-+		if (unlikely(!new->name)) {
-+			kmem_cache_free(unionfs_filldir_cachep, new);
-+			new = NULL;
-+			goto out;
-+		}
-+	}
-+
-+	memcpy(new->name, name, namelen);
-+	new->name[namelen] = '\0';
-+
-+	rdstate->hashentries++;
-+
-+	list_add(&(new->file_list), head);
-+out:
-+	return err;
-+}
-diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c
-new file mode 100644
-index 0000000..da7d589
---- /dev/null
-+++ b/fs/unionfs/rename.c
-@@ -0,0 +1,478 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * This is a helper function for rename, used when rename ends up with hosed
-+ * over dentries and we need to revert.
-+ */
-+static int unionfs_refresh_lower_dentry(struct dentry *dentry, int bindex)
-+{
-+	struct dentry *lower_dentry;
-+	struct dentry *lower_parent;
-+	int err = 0;
-+
-+	verify_locked(dentry);
-+
-+	unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_CHILD);
-+	lower_parent = unionfs_lower_dentry_idx(dentry->d_parent, bindex);
-+	unionfs_unlock_dentry(dentry->d_parent);
-+
-+	BUG_ON(!S_ISDIR(lower_parent->d_inode->i_mode));
-+
-+	lower_dentry = lookup_one_len(dentry->d_name.name, lower_parent,
-+				      dentry->d_name.len);
-+	if (IS_ERR(lower_dentry)) {
-+		err = PTR_ERR(lower_dentry);
-+		goto out;
-+	}
-+
-+	dput(unionfs_lower_dentry_idx(dentry, bindex));
-+	iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
-+	unionfs_set_lower_inode_idx(dentry->d_inode, bindex, NULL);
-+
-+	if (!lower_dentry->d_inode) {
-+		dput(lower_dentry);
-+		unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+	} else {
-+		unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
-+		unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
-+					    igrab(lower_dentry->d_inode));
-+	}
-+
-+out:
-+	return err;
-+}
-+
-+static int __unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-+			    struct inode *new_dir, struct dentry *new_dentry,
-+			    int bindex)
-+{
-+	int err = 0;
-+	struct dentry *lower_old_dentry;
-+	struct dentry *lower_new_dentry;
-+	struct dentry *lower_old_dir_dentry;
-+	struct dentry *lower_new_dir_dentry;
-+	struct dentry *trap;
-+
-+	lower_new_dentry = unionfs_lower_dentry_idx(new_dentry, bindex);
-+	lower_old_dentry = unionfs_lower_dentry_idx(old_dentry, bindex);
-+
-+	if (!lower_new_dentry) {
-+		lower_new_dentry =
-+			create_parents(new_dentry->d_parent->d_inode,
-+				       new_dentry, new_dentry->d_name.name,
-+				       bindex);
-+		if (IS_ERR(lower_new_dentry)) {
-+			err = PTR_ERR(lower_new_dentry);
-+			if (IS_COPYUP_ERR(err))
-+				goto out;
-+			printk(KERN_ERR "unionfs: error creating directory "
-+			       "tree for rename, bindex=%d err=%d\n",
-+			       bindex, err);
-+			goto out;
-+		}
-+	}
-+
-+	/* check for and remove whiteout, if any */
-+	err = check_unlink_whiteout(new_dentry, lower_new_dentry, bindex);
-+	if (err > 0) /* ignore if whiteout found and successfully removed */
-+		err = 0;
-+	if (err)
-+		goto out;
-+
-+	/* check of old_dentry branch is writable */
-+	err = is_robranch_super(old_dentry->d_sb, bindex);
-+	if (err)
-+		goto out;
-+
-+	dget(lower_old_dentry);
-+	dget(lower_new_dentry);
-+	lower_old_dir_dentry = dget_parent(lower_old_dentry);
-+	lower_new_dir_dentry = dget_parent(lower_new_dentry);
-+
-+	/* see Documentation/filesystems/unionfs/issues.txt */
-+	lockdep_off();
-+	trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
-+	/* source should not be ancenstor of target */
-+	if (trap == lower_old_dentry) {
-+		err = -EINVAL;
-+		goto out_err_unlock;
-+	}
-+	/* target should not be ancenstor of source */
-+	if (trap == lower_new_dentry) {
-+		err = -ENOTEMPTY;
-+		goto out_err_unlock;
-+	}
-+	err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
-+			 lower_new_dir_dentry->d_inode, lower_new_dentry);
-+out_err_unlock:
-+	if (!err) {
-+		/* update parent dir times */
-+		fsstack_copy_attr_times(old_dir, lower_old_dir_dentry->d_inode);
-+		fsstack_copy_attr_times(new_dir, lower_new_dir_dentry->d_inode);
-+	}
-+	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
-+	lockdep_on();
-+
-+	dput(lower_old_dir_dentry);
-+	dput(lower_new_dir_dentry);
-+	dput(lower_old_dentry);
-+	dput(lower_new_dentry);
-+
-+out:
-+	if (!err) {
-+		/* Fixup the new_dentry. */
-+		if (bindex < dbstart(new_dentry))
-+			dbstart(new_dentry) = bindex;
-+		else if (bindex > dbend(new_dentry))
-+			dbend(new_dentry) = bindex;
-+	}
-+
-+	return err;
-+}
-+
-+/*
-+ * Main rename code.  This is sufficiently complex, that it's documented in
-+ * Documentation/filesystems/unionfs/rename.txt.  This routine calls
-+ * __unionfs_rename() above to perform some of the work.
-+ */
-+static int do_unionfs_rename(struct inode *old_dir,
-+			     struct dentry *old_dentry,
-+			     struct inode *new_dir,
-+			     struct dentry *new_dentry)
-+{
-+	int err = 0;
-+	int bindex, bwh_old;
-+	int old_bstart, old_bend;
-+	int new_bstart, new_bend;
-+	int do_copyup = -1;
-+	struct dentry *parent_dentry;
-+	int local_err = 0;
-+	int eio = 0;
-+	int revert = 0;
-+
-+	old_bstart = dbstart(old_dentry);
-+	bwh_old = old_bstart;
-+	old_bend = dbend(old_dentry);
-+	parent_dentry = old_dentry->d_parent;
-+
-+	new_bstart = dbstart(new_dentry);
-+	new_bend = dbend(new_dentry);
-+
-+	/* Rename source to destination. */
-+	err = __unionfs_rename(old_dir, old_dentry, new_dir, new_dentry,
-+			       old_bstart);
-+	if (err) {
-+		if (!IS_COPYUP_ERR(err))
-+			goto out;
-+		do_copyup = old_bstart - 1;
-+	} else {
-+		revert = 1;
-+	}
-+
-+	/*
-+	 * Unlink all instances of destination that exist to the left of
-+	 * bstart of source. On error, revert back, goto out.
-+	 */
-+	for (bindex = old_bstart - 1; bindex >= new_bstart; bindex--) {
-+		struct dentry *unlink_dentry;
-+		struct dentry *unlink_dir_dentry;
-+
-+		BUG_ON(bindex < 0);
-+		unlink_dentry = unionfs_lower_dentry_idx(new_dentry, bindex);
-+		if (!unlink_dentry)
-+			continue;
-+
-+		unlink_dir_dentry = lock_parent(unlink_dentry);
-+		err = is_robranch_super(old_dir->i_sb, bindex);
-+		if (!err)
-+			err = vfs_unlink(unlink_dir_dentry->d_inode,
-+					 unlink_dentry);
-+
-+		fsstack_copy_attr_times(new_dentry->d_parent->d_inode,
-+					unlink_dir_dentry->d_inode);
-+		/* propagate number of hard-links */
-+		new_dentry->d_parent->d_inode->i_nlink =
-+			unionfs_get_nlinks(new_dentry->d_parent->d_inode);
-+
-+		unlock_dir(unlink_dir_dentry);
-+		if (!err) {
-+			if (bindex != new_bstart) {
-+				dput(unlink_dentry);
-+				unionfs_set_lower_dentry_idx(new_dentry,
-+							     bindex, NULL);
-+			}
-+		} else if (IS_COPYUP_ERR(err)) {
-+			do_copyup = bindex - 1;
-+		} else if (revert) {
-+			goto revert;
-+		}
-+	}
-+
-+	if (do_copyup != -1) {
-+		for (bindex = do_copyup; bindex >= 0; bindex--) {
-+			/*
-+			 * copyup the file into some left directory, so that
-+			 * you can rename it
-+			 */
-+			err = copyup_dentry(old_dentry->d_parent->d_inode,
-+					    old_dentry, old_bstart, bindex,
-+					    old_dentry->d_name.name,
-+					    old_dentry->d_name.len, NULL,
-+					    i_size_read(old_dentry->d_inode));
-+			/* if copyup failed, try next branch to the left */
-+			if (err)
-+				continue;
-+			bwh_old = bindex;
-+			err = __unionfs_rename(old_dir, old_dentry,
-+					       new_dir, new_dentry,
-+					       bindex);
-+			break;
-+		}
-+	}
-+
-+	/* make it opaque */
-+	if (S_ISDIR(old_dentry->d_inode->i_mode)) {
-+		err = make_dir_opaque(old_dentry, dbstart(old_dentry));
-+		if (err)
-+			goto revert;
-+	}
-+
-+	/*
-+	 * Create whiteout for source, only if:
-+	 * (1) There is more than one underlying instance of source.
-+	 * (2) We did a copy_up
-+	 */
-+	if ((old_bstart != old_bend) || (do_copyup != -1)) {
-+		if (bwh_old < 0) {
-+			printk(KERN_ERR "unionfs: rename error (bwh_old=%d)\n",
-+			       bwh_old);
-+			err = -EIO;
-+			goto out;
-+		}
-+		err = create_whiteout(old_dentry, bwh_old);
-+		if (err) {
-+			/* can't fix anything now, so we exit with -EIO */
-+			printk(KERN_ERR "unionfs: can't create a whiteout for "
-+			       "%s in rename!\n", old_dentry->d_name.name);
-+			err = -EIO;
-+		}
-+	}
-+
-+out:
-+	return err;
-+
-+revert:
-+	/* Do revert here. */
-+	local_err = unionfs_refresh_lower_dentry(new_dentry, old_bstart);
-+	if (local_err) {
-+		printk(KERN_ERR "unionfs: revert failed in rename: "
-+		       "the new refresh failed\n");
-+		eio = -EIO;
-+	}
-+
-+	local_err = unionfs_refresh_lower_dentry(old_dentry, old_bstart);
-+	if (local_err) {
-+		printk(KERN_ERR "unionfs: revert failed in rename: "
-+		       "the old refresh failed\n");
-+		eio = -EIO;
-+		goto revert_out;
-+	}
-+
-+	if (!unionfs_lower_dentry_idx(new_dentry, bindex) ||
-+	    !unionfs_lower_dentry_idx(new_dentry, bindex)->d_inode) {
-+		printk(KERN_ERR "unionfs: revert failed in rename: "
-+		       "the object disappeared from under us!\n");
-+		eio = -EIO;
-+		goto revert_out;
-+	}
-+
-+	if (unionfs_lower_dentry_idx(old_dentry, bindex) &&
-+	    unionfs_lower_dentry_idx(old_dentry, bindex)->d_inode) {
-+		printk(KERN_ERR "unionfs: revert failed in rename: "
-+		       "the object was created underneath us!\n");
-+		eio = -EIO;
-+		goto revert_out;
-+	}
-+
-+	local_err = __unionfs_rename(new_dir, new_dentry,
-+				     old_dir, old_dentry, old_bstart);
-+
-+	/* If we can't fix it, then we cop-out with -EIO. */
-+	if (local_err) {
-+		printk(KERN_ERR "unionfs: revert failed in rename!\n");
-+		eio = -EIO;
-+	}
-+
-+	local_err = unionfs_refresh_lower_dentry(new_dentry, bindex);
-+	if (local_err)
-+		eio = -EIO;
-+	local_err = unionfs_refresh_lower_dentry(old_dentry, bindex);
-+	if (local_err)
-+		eio = -EIO;
-+
-+revert_out:
-+	if (eio)
-+		err = eio;
-+	return err;
-+}
-+
-+/*
-+ * We can't copyup a directory, because it may involve huge numbers of
-+ * children, etc.  Doing that in the kernel would be bad, so instead we
-+ * return EXDEV to the user-space utility that caused this, and let the
-+ * user-space recurse and ask us to copy up each file separately.
-+ */
-+static int may_rename_dir(struct dentry *dentry)
-+{
-+	int err, bstart;
-+
-+	err = check_empty(dentry, NULL);
-+	if (err == -ENOTEMPTY) {
-+		if (is_robranch(dentry))
-+			return -EXDEV;
-+	} else if (err) {
-+		return err;
-+	}
-+
-+	bstart = dbstart(dentry);
-+	if (dbend(dentry) == bstart || dbopaque(dentry) == bstart)
-+		return 0;
-+
-+	dbstart(dentry) = bstart + 1;
-+	err = check_empty(dentry, NULL);
-+	dbstart(dentry) = bstart;
-+	if (err == -ENOTEMPTY)
-+		err = -EXDEV;
-+	return err;
-+}
-+
-+int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-+		   struct inode *new_dir, struct dentry *new_dentry)
-+{
-+	int err = 0;
-+	struct dentry *wh_dentry;
-+
-+	unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_double_lock_dentry(old_dentry, new_dentry);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(old_dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+	if (unlikely(!d_deleted(new_dentry) && new_dentry->d_inode &&
-+		     !__unionfs_d_revalidate_chain(new_dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	if (!S_ISDIR(old_dentry->d_inode->i_mode))
-+		err = unionfs_partial_lookup(old_dentry);
-+	else
-+		err = may_rename_dir(old_dentry);
-+
-+	if (err)
-+		goto out;
-+
-+	err = unionfs_partial_lookup(new_dentry);
-+	if (err)
-+		goto out;
-+
-+	/*
-+	 * if new_dentry is already lower because of whiteout,
-+	 * simply override it even if the whited-out dir is not empty.
-+	 */
-+	wh_dentry = find_first_whiteout(new_dentry);
-+	if (!IS_ERR(wh_dentry)) {
-+		dput(wh_dentry);
-+	} else if (new_dentry->d_inode) {
-+		if (S_ISDIR(old_dentry->d_inode->i_mode) !=
-+		    S_ISDIR(new_dentry->d_inode->i_mode)) {
-+			err = S_ISDIR(old_dentry->d_inode->i_mode) ?
-+				-ENOTDIR : -EISDIR;
-+			goto out;
-+		}
-+
-+		if (S_ISDIR(new_dentry->d_inode->i_mode)) {
-+			struct unionfs_dir_state *namelist = NULL;
-+			/* check if this unionfs directory is empty or not */
-+			err = check_empty(new_dentry, &namelist);
-+			if (err)
-+				goto out;
-+
-+			if (!is_robranch(new_dentry))
-+				err = delete_whiteouts(new_dentry,
-+						       dbstart(new_dentry),
-+						       namelist);
-+
-+			free_rdstate(namelist);
-+
-+			if (err)
-+				goto out;
-+		}
-+	}
-+
-+	err = do_unionfs_rename(old_dir, old_dentry, new_dir, new_dentry);
-+	if (err)
-+		goto out;
-+
-+	/*
-+	 * force re-lookup since the dir on ro branch is not renamed, and
-+	 * lower dentries still indicate the un-renamed ones.
-+	 */
-+	if (S_ISDIR(old_dentry->d_inode->i_mode))
-+		atomic_dec(&UNIONFS_D(old_dentry)->generation);
-+	else
-+		unionfs_postcopyup_release(old_dentry);
-+	if (new_dentry->d_inode && !S_ISDIR(new_dentry->d_inode->i_mode)) {
-+		unionfs_postcopyup_release(new_dentry);
-+		unionfs_postcopyup_setmnt(new_dentry);
-+		if (!unionfs_lower_inode(new_dentry->d_inode)) {
-+			/*
-+			 * If we get here, it means that no copyup was
-+			 * needed, and that a file by the old name already
-+			 * existing on the destination branch; that file got
-+			 * renamed earlier in this function, so all we need
-+			 * to do here is set the lower inode.
-+			 */
-+			struct inode *inode;
-+			inode = unionfs_lower_inode(old_dentry->d_inode);
-+			igrab(inode);
-+			unionfs_set_lower_inode_idx(new_dentry->d_inode,
-+						    dbstart(new_dentry),
-+						    inode);
-+		}
-+	}
-+	/* if all of this renaming succeeded, update our times */
-+	unionfs_copy_attr_times(old_dentry->d_inode);
-+	unionfs_copy_attr_times(new_dentry->d_inode);
-+	unionfs_check_inode(old_dir);
-+	unionfs_check_inode(new_dir);
-+	unionfs_check_dentry(old_dentry);
-+	unionfs_check_dentry(new_dentry);
-+
-+out:
-+	if (err)		/* clear the new_dentry stuff created */
-+		d_drop(new_dentry);
-+	unionfs_unlock_dentry(new_dentry);
-+	unionfs_unlock_dentry(old_dentry);
-+	unionfs_read_unlock(old_dentry->d_sb);
-+	return err;
-+}
-diff --git a/fs/unionfs/sioq.c b/fs/unionfs/sioq.c
-new file mode 100644
-index 0000000..dd45e39
---- /dev/null
-+++ b/fs/unionfs/sioq.c
-@@ -0,0 +1,101 @@
-+/*
-+ * Copyright (c) 2006-2008 Erez Zadok
-+ * Copyright (c) 2006      Charles P. Wright
-+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2006      Junjiro Okajima
-+ * Copyright (c) 2006      David P. Quigley
-+ * Copyright (c) 2006-2008 Stony Brook University
-+ * Copyright (c) 2006-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Super-user IO work Queue - sometimes we need to perform actions which
-+ * would fail due to the unix permissions on the parent directory (e.g.,
-+ * rmdir a directory which appears empty, but in reality contains
-+ * whiteouts).
-+ */
-+
-+static struct workqueue_struct *superio_workqueue;
-+
-+int __init init_sioq(void)
-+{
-+	int err;
-+
-+	superio_workqueue = create_workqueue("unionfs_siod");
-+	if (!IS_ERR(superio_workqueue))
-+		return 0;
-+
-+	err = PTR_ERR(superio_workqueue);
-+	printk(KERN_ERR "unionfs: create_workqueue failed %d\n", err);
-+	superio_workqueue = NULL;
-+	return err;
-+}
-+
-+void stop_sioq(void)
-+{
-+	if (superio_workqueue)
-+		destroy_workqueue(superio_workqueue);
-+}
-+
-+void run_sioq(work_func_t func, struct sioq_args *args)
-+{
-+	INIT_WORK(&args->work, func);
-+
-+	init_completion(&args->comp);
-+	while (!queue_work(superio_workqueue, &args->work)) {
-+		/* TODO: do accounting if needed */
-+		schedule();
-+	}
-+	wait_for_completion(&args->comp);
-+}
-+
-+void __unionfs_create(struct work_struct *work)
-+{
-+	struct sioq_args *args = container_of(work, struct sioq_args, work);
-+	struct create_args *c = &args->create;
-+
-+	args->err = vfs_create(c->parent, c->dentry, c->mode, c->nd);
-+	complete(&args->comp);
-+}
-+
-+void __unionfs_mkdir(struct work_struct *work)
-+{
-+	struct sioq_args *args = container_of(work, struct sioq_args, work);
-+	struct mkdir_args *m = &args->mkdir;
-+
-+	args->err = vfs_mkdir(m->parent, m->dentry, m->mode);
-+	complete(&args->comp);
-+}
-+
-+void __unionfs_mknod(struct work_struct *work)
-+{
-+	struct sioq_args *args = container_of(work, struct sioq_args, work);
-+	struct mknod_args *m = &args->mknod;
-+
-+	args->err = vfs_mknod(m->parent, m->dentry, m->mode, m->dev);
-+	complete(&args->comp);
-+}
-+
-+void __unionfs_symlink(struct work_struct *work)
-+{
-+	struct sioq_args *args = container_of(work, struct sioq_args, work);
-+	struct symlink_args *s = &args->symlink;
-+
-+	args->err = vfs_symlink(s->parent, s->dentry, s->symbuf);
-+	complete(&args->comp);
-+}
-+
-+void __unionfs_unlink(struct work_struct *work)
-+{
-+	struct sioq_args *args = container_of(work, struct sioq_args, work);
-+	struct unlink_args *u = &args->unlink;
-+
-+	args->err = vfs_unlink(u->parent, u->dentry);
-+	complete(&args->comp);
-+}
-diff --git a/fs/unionfs/sioq.h b/fs/unionfs/sioq.h
-new file mode 100644
-index 0000000..679a0df
---- /dev/null
-+++ b/fs/unionfs/sioq.h
-@@ -0,0 +1,91 @@
-+/*
-+ * Copyright (c) 2006-2008 Erez Zadok
-+ * Copyright (c) 2006      Charles P. Wright
-+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2006      Junjiro Okajima
-+ * Copyright (c) 2006      David P. Quigley
-+ * Copyright (c) 2006-2008 Stony Brook University
-+ * Copyright (c) 2006-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#ifndef _SIOQ_H
-+#define _SIOQ_H
-+
-+struct deletewh_args {
-+	struct unionfs_dir_state *namelist;
-+	struct dentry *dentry;
-+	int bindex;
-+};
-+
-+struct is_opaque_args {
-+	struct dentry *dentry;
-+};
-+
-+struct create_args {
-+	struct inode *parent;
-+	struct dentry *dentry;
-+	umode_t mode;
-+	struct nameidata *nd;
-+};
-+
-+struct mkdir_args {
-+	struct inode *parent;
-+	struct dentry *dentry;
-+	umode_t mode;
-+};
-+
-+struct mknod_args {
-+	struct inode *parent;
-+	struct dentry *dentry;
-+	umode_t mode;
-+	dev_t dev;
-+};
-+
-+struct symlink_args {
-+	struct inode *parent;
-+	struct dentry *dentry;
-+	char *symbuf;
-+};
-+
-+struct unlink_args {
-+	struct inode *parent;
-+	struct dentry *dentry;
-+};
-+
-+
-+struct sioq_args {
-+	struct completion comp;
-+	struct work_struct work;
-+	int err;
-+	void *ret;
-+
-+	union {
-+		struct deletewh_args deletewh;
-+		struct is_opaque_args is_opaque;
-+		struct create_args create;
-+		struct mkdir_args mkdir;
-+		struct mknod_args mknod;
-+		struct symlink_args symlink;
-+		struct unlink_args unlink;
-+	};
-+};
-+
-+/* Extern definitions for SIOQ functions */
-+extern int __init init_sioq(void);
-+extern void stop_sioq(void);
-+extern void run_sioq(work_func_t func, struct sioq_args *args);
-+
-+/* Extern definitions for our privilege escalation helpers */
-+extern void __unionfs_create(struct work_struct *work);
-+extern void __unionfs_mkdir(struct work_struct *work);
-+extern void __unionfs_mknod(struct work_struct *work);
-+extern void __unionfs_symlink(struct work_struct *work);
-+extern void __unionfs_unlink(struct work_struct *work);
-+extern void __delete_whiteouts(struct work_struct *work);
-+extern void __is_opaque_dir(struct work_struct *work);
-+
-+#endif /* not _SIOQ_H */
-diff --git a/fs/unionfs/subr.c b/fs/unionfs/subr.c
-new file mode 100644
-index 0000000..8747d20
---- /dev/null
-+++ b/fs/unionfs/subr.c
-@@ -0,0 +1,95 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * returns the right n_link value based on the inode type
-+ */
-+int unionfs_get_nlinks(const struct inode *inode)
-+{
-+	/* don't bother to do all the work since we're unlinked */
-+	if (inode->i_nlink == 0)
-+		return 0;
-+
-+	if (!S_ISDIR(inode->i_mode))
-+		return unionfs_lower_inode(inode)->i_nlink;
-+
-+	/*
-+	 * For directories, we return 1. The only place that could cares
-+	 * about links is readdir, and there's d_type there so even that
-+	 * doesn't matter.
-+	 */
-+	return 1;
-+}
-+
-+/* copy a/m/ctime from the lower branch with the newest times */
-+void unionfs_copy_attr_times(struct inode *upper)
-+{
-+	int bindex;
-+	struct inode *lower;
-+
-+	if (!upper)
-+		return;
-+	if (ibstart(upper) < 0) {
-+#ifdef CONFIG_UNION_FS_DEBUG
-+		WARN_ON(ibstart(upper) < 0);
-+#endif /* CONFIG_UNION_FS_DEBUG */
-+		return;
-+	}
-+	for (bindex = ibstart(upper); bindex <= ibend(upper); bindex++) {
-+		lower = unionfs_lower_inode_idx(upper, bindex);
-+		if (!lower)
-+			continue; /* not all lower dir objects may exist */
-+		if (unlikely(timespec_compare(&upper->i_mtime,
-+					      &lower->i_mtime) < 0))
-+			upper->i_mtime = lower->i_mtime;
-+		if (unlikely(timespec_compare(&upper->i_ctime,
-+					      &lower->i_ctime) < 0))
-+			upper->i_ctime = lower->i_ctime;
-+		if (unlikely(timespec_compare(&upper->i_atime,
-+					      &lower->i_atime) < 0))
-+			upper->i_atime = lower->i_atime;
-+	}
-+}
-+
-+/*
-+ * A unionfs/fanout version of fsstack_copy_attr_all.  Uses a
-+ * unionfs_get_nlinks to properly calcluate the number of links to a file.
-+ * Also, copies the max() of all a/m/ctimes for all lower inodes (which is
-+ * important if the lower inode is a directory type)
-+ */
-+void unionfs_copy_attr_all(struct inode *dest,
-+			   const struct inode *src)
-+{
-+	dest->i_mode = src->i_mode;
-+	dest->i_uid = src->i_uid;
-+	dest->i_gid = src->i_gid;
-+	dest->i_rdev = src->i_rdev;
-+
-+	unionfs_copy_attr_times(dest);
-+
-+	dest->i_blkbits = src->i_blkbits;
-+	dest->i_flags = src->i_flags;
-+
-+	/*
-+	 * Update the nlinks AFTER updating the above fields, because the
-+	 * get_links callback may depend on them.
-+	 */
-+	dest->i_nlink = unionfs_get_nlinks(dest);
-+}
-diff --git a/fs/unionfs/super.c b/fs/unionfs/super.c
-new file mode 100644
-index 0000000..e774ef3
---- /dev/null
-+++ b/fs/unionfs/super.c
-@@ -0,0 +1,1042 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * The inode cache is used with alloc_inode for both our inode info and the
-+ * vfs inode.
-+ */
-+static struct kmem_cache *unionfs_inode_cachep;
-+
-+struct inode *unionfs_iget(struct super_block *sb, unsigned long ino)
-+{
-+	int size;
-+	struct unionfs_inode_info *info;
-+	struct inode *inode;
-+
-+	inode = iget_locked(sb, ino);
-+	if (!inode)
-+		return ERR_PTR(-ENOMEM);
-+	if (!(inode->i_state & I_NEW))
-+		return inode;
-+
-+	info = UNIONFS_I(inode);
-+	memset(info, 0, offsetof(struct unionfs_inode_info, vfs_inode));
-+	info->bstart = -1;
-+	info->bend = -1;
-+	atomic_set(&info->generation,
-+		   atomic_read(&UNIONFS_SB(inode->i_sb)->generation));
-+	spin_lock_init(&info->rdlock);
-+	info->rdcount = 1;
-+	info->hashsize = -1;
-+	INIT_LIST_HEAD(&info->readdircache);
-+
-+	size = sbmax(inode->i_sb) * sizeof(struct inode *);
-+	info->lower_inodes = kzalloc(size, GFP_KERNEL);
-+	if (unlikely(!info->lower_inodes)) {
-+		printk(KERN_CRIT "unionfs: no kernel memory when allocating "
-+		       "lower-pointer array!\n");
-+		iget_failed(inode);
-+		return ERR_PTR(-ENOMEM);
-+	}
-+
-+	inode->i_version++;
-+	inode->i_op = &unionfs_main_iops;
-+	inode->i_fop = &unionfs_main_fops;
-+
-+	inode->i_mapping->a_ops = &unionfs_aops;
-+
-+	/*
-+	 * reset times so unionfs_copy_attr_all can keep out time invariants
-+	 * right (upper inode time being the max of all lower ones).
-+	 */
-+	inode->i_atime.tv_sec = inode->i_atime.tv_nsec = 0;
-+	inode->i_mtime.tv_sec = inode->i_mtime.tv_nsec = 0;
-+	inode->i_ctime.tv_sec = inode->i_ctime.tv_nsec = 0;
-+	unlock_new_inode(inode);
-+	return inode;
-+}
-+
-+/*
-+ * we now define delete_inode, because there are two VFS paths that may
-+ * destroy an inode: one of them calls clear inode before doing everything
-+ * else that's needed, and the other is fine.  This way we truncate the inode
-+ * size (and its pages) and then clear our own inode, which will do an iput
-+ * on our and the lower inode.
-+ *
-+ * No need to lock sb info's rwsem.
-+ */
-+static void unionfs_delete_inode(struct inode *inode)
-+{
-+#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
-+	spin_lock(&inode->i_lock);
-+#endif
-+	i_size_write(inode, 0);	/* every f/s seems to do that */
-+#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
-+	spin_unlock(&inode->i_lock);
-+#endif
-+
-+	if (inode->i_data.nrpages)
-+		truncate_inode_pages(&inode->i_data, 0);
-+
-+	clear_inode(inode);
-+}
-+
-+/*
-+ * final actions when unmounting a file system
-+ *
-+ * No need to lock rwsem.
-+ */
-+static void unionfs_put_super(struct super_block *sb)
-+{
-+	int bindex, bstart, bend;
-+	struct unionfs_sb_info *spd;
-+	int leaks = 0;
-+
-+	spd = UNIONFS_SB(sb);
-+	if (!spd)
-+		return;
-+
-+	bstart = sbstart(sb);
-+	bend = sbend(sb);
-+
-+	/* Make sure we have no leaks of branchget/branchput. */
-+	for (bindex = bstart; bindex <= bend; bindex++)
-+		if (unlikely(branch_count(sb, bindex) != 0)) {
-+			printk(KERN_CRIT
-+			       "unionfs: branch %d has %d references left!\n",
-+			       bindex, branch_count(sb, bindex));
-+			leaks = 1;
-+		}
-+	BUG_ON(leaks != 0);
-+
-+	/* decrement lower super references */
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		struct super_block *s;
-+		s = unionfs_lower_super_idx(sb, bindex);
-+		unionfs_set_lower_super_idx(sb, bindex, NULL);
-+		atomic_dec(&s->s_active);
-+	}
-+
-+	kfree(spd->dev_name);
-+	kfree(spd->data);
-+	kfree(spd);
-+	sb->s_fs_info = NULL;
-+}
-+
-+/*
-+ * Since people use this to answer the "How big of a file can I write?"
-+ * question, we report the size of the highest priority branch as the size of
-+ * the union.
-+ */
-+static int unionfs_statfs(struct dentry *dentry, struct kstatfs *buf)
-+{
-+	int err	= 0;
-+	struct super_block *sb;
-+	struct dentry *lower_dentry;
-+
-+	sb = dentry->d_sb;
-+
-+	unionfs_read_lock(sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+	unionfs_check_dentry(dentry);
-+
-+	lower_dentry = unionfs_lower_dentry(sb->s_root);
-+	err = vfs_statfs(lower_dentry, buf);
-+
-+	/* set return buf to our f/s to avoid confusing user-level utils */
-+	buf->f_type = UNIONFS_SUPER_MAGIC;
-+	/*
-+	 * Our maximum file name can is shorter by a few bytes because every
-+	 * file name could potentially be whited-out.
-+	 *
-+	 * XXX: this restriction goes away with ODF.
-+	 */
-+	unionfs_set_max_namelen(&buf->f_namelen);
-+
-+	/*
-+	 * reset two fields to avoid confusing user-land.
-+	 * XXX: is this still necessary?
-+	 */
-+	memset(&buf->f_fsid, 0, sizeof(__kernel_fsid_t));
-+	memset(&buf->f_spare, 0, sizeof(buf->f_spare));
-+
-+out:
-+	unionfs_check_dentry(dentry);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(sb);
-+	return err;
-+}
-+
-+/* handle mode changing during remount */
-+static noinline_for_stack int do_remount_mode_option(
-+					char *optarg,
-+					int cur_branches,
-+					struct unionfs_data *new_data,
-+					struct path *new_lower_paths)
-+{
-+	int err = -EINVAL;
-+	int perms, idx;
-+	char *modename = strchr(optarg, '=');
-+	struct nameidata nd;
-+
-+	/* by now, optarg contains the branch name */
-+	if (!*optarg) {
-+		printk(KERN_ERR
-+		       "unionfs: no branch specified for mode change\n");
-+		goto out;
-+	}
-+	if (!modename) {
-+		printk(KERN_ERR "unionfs: branch \"%s\" requires a mode\n",
-+		       optarg);
-+		goto out;
-+	}
-+	*modename++ = '\0';
-+	err = parse_branch_mode(modename, &perms);
-+	if (err) {
-+		printk(KERN_ERR "unionfs: invalid mode \"%s\" for \"%s\"\n",
-+		       modename, optarg);
-+		goto out;
-+	}
-+
-+	/*
-+	 * Find matching branch index.  For now, this assumes that nothing
-+	 * has been mounted on top of this Unionfs stack.  Once we have /odf
-+	 * and cache-coherency resolved, we'll address the branch-path
-+	 * uniqueness.
-+	 */
-+	err = path_lookup(optarg, LOOKUP_FOLLOW, &nd);
-+	if (err) {
-+		printk(KERN_ERR "unionfs: error accessing "
-+		       "lower directory \"%s\" (error %d)\n",
-+		       optarg, err);
-+		goto out;
-+	}
-+	for (idx = 0; idx < cur_branches; idx++)
-+		if (nd.path.mnt == new_lower_paths[idx].mnt &&
-+		    nd.path.dentry == new_lower_paths[idx].dentry)
-+			break;
-+	path_put(&nd.path);	/* no longer needed */
-+	if (idx == cur_branches) {
-+		err = -ENOENT;	/* err may have been reset above */
-+		printk(KERN_ERR "unionfs: branch \"%s\" "
-+		       "not found\n", optarg);
-+		goto out;
-+	}
-+	/* check/change mode for existing branch */
-+	/* we don't warn if perms==branchperms */
-+	new_data[idx].branchperms = perms;
-+	err = 0;
-+out:
-+	return err;
-+}
-+
-+/* handle branch deletion during remount */
-+static noinline_for_stack int do_remount_del_option(
-+					char *optarg, int cur_branches,
-+					struct unionfs_data *new_data,
-+					struct path *new_lower_paths)
-+{
-+	int err = -EINVAL;
-+	int idx;
-+	struct nameidata nd;
-+
-+	/* optarg contains the branch name to delete */
-+
-+	/*
-+	 * Find matching branch index.  For now, this assumes that nothing
-+	 * has been mounted on top of this Unionfs stack.  Once we have /odf
-+	 * and cache-coherency resolved, we'll address the branch-path
-+	 * uniqueness.
-+	 */
-+	err = path_lookup(optarg, LOOKUP_FOLLOW, &nd);
-+	if (err) {
-+		printk(KERN_ERR "unionfs: error accessing "
-+		       "lower directory \"%s\" (error %d)\n",
-+		       optarg, err);
-+		goto out;
-+	}
-+	for (idx = 0; idx < cur_branches; idx++)
-+		if (nd.path.mnt == new_lower_paths[idx].mnt &&
-+		    nd.path.dentry == new_lower_paths[idx].dentry)
-+			break;
-+	path_put(&nd.path);	/* no longer needed */
-+	if (idx == cur_branches) {
-+		printk(KERN_ERR "unionfs: branch \"%s\" "
-+		       "not found\n", optarg);
-+		err = -ENOENT;
-+		goto out;
-+	}
-+	/* check if there are any open files on the branch to be deleted */
-+	if (atomic_read(&new_data[idx].open_files) > 0) {
-+		err = -EBUSY;
-+		goto out;
-+	}
-+
-+	/*
-+	 * Now we have to delete the branch.  First, release any handles it
-+	 * has.  Then, move the remaining array indexes past "idx" in
-+	 * new_data and new_lower_paths one to the left.  Finally, adjust
-+	 * cur_branches.
-+	 */
-+	path_put(&new_lower_paths[idx]);
-+
-+	if (idx < cur_branches - 1) {
-+		/* if idx==cur_branches-1, we delete last branch: easy */
-+		memmove(&new_data[idx], &new_data[idx+1],
-+			(cur_branches - 1 - idx) *
-+			sizeof(struct unionfs_data));
-+		memmove(&new_lower_paths[idx], &new_lower_paths[idx+1],
-+			(cur_branches - 1 - idx) * sizeof(struct path));
-+	}
-+
-+	err = 0;
-+out:
-+	return err;
-+}
-+
-+/* handle branch insertion during remount */
-+static noinline_for_stack int do_remount_add_option(
-+					char *optarg, int cur_branches,
-+					struct unionfs_data *new_data,
-+					struct path *new_lower_paths,
-+					int *high_branch_id)
-+{
-+	int err = -EINVAL;
-+	int perms;
-+	int idx = 0;		/* default: insert at beginning */
-+	char *new_branch , *modename = NULL;
-+	struct nameidata nd;
-+
-+	/*
-+	 * optarg can be of several forms:
-+	 *
-+	 * /bar:/foo		insert /foo before /bar
-+	 * /bar:/foo=ro		insert /foo in ro mode before /bar
-+	 * /foo			insert /foo in the beginning (prepend)
-+	 * :/foo		insert /foo at the end (append)
-+	 */
-+	if (*optarg == ':') {	/* append? */
-+		new_branch = optarg + 1; /* skip ':' */
-+		idx = cur_branches;
-+		goto found_insertion_point;
-+	}
-+	new_branch = strchr(optarg, ':');
-+	if (!new_branch) {	/* prepend? */
-+		new_branch = optarg;
-+		goto found_insertion_point;
-+	}
-+	*new_branch++ = '\0';	/* holds path+mode of new branch */
-+
-+	/*
-+	 * Find matching branch index.  For now, this assumes that nothing
-+	 * has been mounted on top of this Unionfs stack.  Once we have /odf
-+	 * and cache-coherency resolved, we'll address the branch-path
-+	 * uniqueness.
-+	 */
-+	err = path_lookup(optarg, LOOKUP_FOLLOW, &nd);
-+	if (err) {
-+		printk(KERN_ERR "unionfs: error accessing "
-+		       "lower directory \"%s\" (error %d)\n",
-+		       optarg, err);
-+		goto out;
-+	}
-+	for (idx = 0; idx < cur_branches; idx++)
-+		if (nd.path.mnt == new_lower_paths[idx].mnt &&
-+		    nd.path.dentry == new_lower_paths[idx].dentry)
-+			break;
-+	path_put(&nd.path);	/* no longer needed */
-+	if (idx == cur_branches) {
-+		printk(KERN_ERR "unionfs: branch \"%s\" "
-+		       "not found\n", optarg);
-+		err = -ENOENT;
-+		goto out;
-+	}
-+
-+	/*
-+	 * At this point idx will hold the index where the new branch should
-+	 * be inserted before.
-+	 */
-+found_insertion_point:
-+	/* find the mode for the new branch */
-+	if (new_branch)
-+		modename = strchr(new_branch, '=');
-+	if (modename)
-+		*modename++ = '\0';
-+	if (!new_branch || !*new_branch) {
-+		printk(KERN_ERR "unionfs: null new branch\n");
-+		err = -EINVAL;
-+		goto out;
-+	}
-+	err = parse_branch_mode(modename, &perms);
-+	if (err) {
-+		printk(KERN_ERR "unionfs: invalid mode \"%s\" for "
-+		       "branch \"%s\"\n", modename, new_branch);
-+		goto out;
-+	}
-+	err = path_lookup(new_branch, LOOKUP_FOLLOW, &nd);
-+	if (err) {
-+		printk(KERN_ERR "unionfs: error accessing "
-+		       "lower directory \"%s\" (error %d)\n",
-+		       new_branch, err);
-+		goto out;
-+	}
-+	/*
-+	 * It's probably safe to check_mode the new branch to insert.  Note:
-+	 * we don't allow inserting branches which are unionfs's by
-+	 * themselves (check_branch returns EINVAL in that case).  This is
-+	 * because this code base doesn't support stacking unionfs: the ODF
-+	 * code base supports that correctly.
-+	 */
-+	err = check_branch(&nd);
-+	if (err) {
-+		printk(KERN_ERR "unionfs: lower directory "
-+		       "\"%s\" is not a valid branch\n", optarg);
-+		path_put(&nd.path);
-+		goto out;
-+	}
-+
-+	/*
-+	 * Now we have to insert the new branch.  But first, move the bits
-+	 * to make space for the new branch, if needed.  Finally, adjust
-+	 * cur_branches.
-+	 * We don't release nd here; it's kept until umount/remount.
-+	 */
-+	if (idx < cur_branches) {
-+		/* if idx==cur_branches, we append: easy */
-+		memmove(&new_data[idx+1], &new_data[idx],
-+			(cur_branches - idx) * sizeof(struct unionfs_data));
-+		memmove(&new_lower_paths[idx+1], &new_lower_paths[idx],
-+			(cur_branches - idx) * sizeof(struct path));
-+	}
-+	new_lower_paths[idx].dentry = nd.path.dentry;
-+	new_lower_paths[idx].mnt = nd.path.mnt;
-+
-+	new_data[idx].sb = nd.path.dentry->d_sb;
-+	atomic_set(&new_data[idx].open_files, 0);
-+	new_data[idx].branchperms = perms;
-+	new_data[idx].branch_id = ++*high_branch_id; /* assign new branch ID */
-+
-+	err = 0;
-+out:
-+	return err;
-+}
-+
-+
-+/*
-+ * Support branch management options on remount.
-+ *
-+ * See Documentation/filesystems/unionfs/ for details.
-+ *
-+ * @flags: numeric mount options
-+ * @options: mount options string
-+ *
-+ * This function can rearrange a mounted union dynamically, adding and
-+ * removing branches, including changing branch modes.  Clearly this has to
-+ * be done safely and atomically.  Luckily, the VFS already calls this
-+ * function with lock_super(sb) and lock_kernel() held, preventing
-+ * concurrent mixing of new mounts, remounts, and unmounts.  Moreover,
-+ * do_remount_sb(), our caller function, already called shrink_dcache_sb(sb)
-+ * to purge dentries/inodes from our superblock, and also called
-+ * fsync_super(sb) to purge any dirty pages.  So we're good.
-+ *
-+ * XXX: however, our remount code may also need to invalidate mapped pages
-+ * so as to force them to be re-gotten from the (newly reconfigured) lower
-+ * branches.  This has to wait for proper mmap and cache coherency support
-+ * in the VFS.
-+ *
-+ */
-+static int unionfs_remount_fs(struct super_block *sb, int *flags,
-+			      char *options)
-+{
-+	int err = 0;
-+	int i;
-+	char *optionstmp, *tmp_to_free;	/* kstrdup'ed of "options" */
-+	char *optname;
-+	int cur_branches = 0;	/* no. of current branches */
-+	int new_branches = 0;	/* no. of branches actually left in the end */
-+	int add_branches;	/* est. no. of branches to add */
-+	int del_branches;	/* est. no. of branches to del */
-+	int max_branches;	/* max possible no. of branches */
-+	struct unionfs_data *new_data = NULL, *tmp_data = NULL;
-+	struct path *new_lower_paths = NULL, *tmp_lower_paths = NULL;
-+	struct inode **new_lower_inodes = NULL;
-+	int new_high_branch_id;	/* new high branch ID */
-+	int size;		/* memory allocation size, temp var */
-+	int old_ibstart, old_ibend;
-+
-+	unionfs_write_lock(sb);
-+
-+	/*
-+	 * The VFS will take care of "ro" and "rw" flags, and we can safely
-+	 * ignore MS_SILENT, but anything else left over is an error.  So we
-+	 * need to check if any other flags may have been passed (none are
-+	 * allowed/supported as of now).
-+	 */
-+	if ((*flags & ~(MS_RDONLY | MS_SILENT)) != 0) {
-+		printk(KERN_ERR
-+		       "unionfs: remount flags 0x%x unsupported\n", *flags);
-+		err = -EINVAL;
-+		goto out_error;
-+	}
-+
-+	/*
-+	 * If 'options' is NULL, it's probably because the user just changed
-+	 * the union to a "ro" or "rw" and the VFS took care of it.  So
-+	 * nothing to do and we're done.
-+	 */
-+	if (!options || options[0] == '\0')
-+		goto out_error;
-+
-+	/*
-+	 * Find out how many branches we will have in the end, counting
-+	 * "add" and "del" commands.  Copy the "options" string because
-+	 * strsep modifies the string and we need it later.
-+	 */
-+	tmp_to_free = kstrdup(options, GFP_KERNEL);
-+	optionstmp = tmp_to_free;
-+	if (unlikely(!optionstmp)) {
-+		err = -ENOMEM;
-+		goto out_free;
-+	}
-+	cur_branches = sbmax(sb); /* current no. branches */
-+	new_branches = sbmax(sb);
-+	del_branches = 0;
-+	add_branches = 0;
-+	new_high_branch_id = sbhbid(sb); /* save current high_branch_id */
-+	while ((optname = strsep(&optionstmp, ",")) != NULL) {
-+		char *optarg;
-+
-+		if (!optname || !*optname)
-+			continue;
-+
-+		optarg = strchr(optname, '=');
-+		if (optarg)
-+			*optarg++ = '\0';
-+
-+		if (!strcmp("add", optname))
-+			add_branches++;
-+		else if (!strcmp("del", optname))
-+			del_branches++;
-+	}
-+	kfree(tmp_to_free);
-+	/* after all changes, will we have at least one branch left? */
-+	if ((new_branches + add_branches - del_branches) < 1) {
-+		printk(KERN_ERR
-+		       "unionfs: no branches left after remount\n");
-+		err = -EINVAL;
-+		goto out_free;
-+	}
-+
-+	/*
-+	 * Since we haven't actually parsed all the add/del options, nor
-+	 * have we checked them for errors, we don't know for sure how many
-+	 * branches we will have after all changes have taken place.  In
-+	 * fact, the total number of branches left could be less than what
-+	 * we have now.  So we need to allocate space for a temporary
-+	 * placeholder that is at least as large as the maximum number of
-+	 * branches we *could* have, which is the current number plus all
-+	 * the additions.  Once we're done with these temp placeholders, we
-+	 * may have to re-allocate the final size, copy over from the temp,
-+	 * and then free the temps (done near the end of this function).
-+	 */
-+	max_branches = cur_branches + add_branches;
-+	/* allocate space for new pointers to lower dentry */
-+	tmp_data = kcalloc(max_branches,
-+			   sizeof(struct unionfs_data), GFP_KERNEL);
-+	if (unlikely(!tmp_data)) {
-+		err = -ENOMEM;
-+		goto out_free;
-+	}
-+	/* allocate space for new pointers to lower paths */
-+	tmp_lower_paths = kcalloc(max_branches,
-+				  sizeof(struct path), GFP_KERNEL);
-+	if (unlikely(!tmp_lower_paths)) {
-+		err = -ENOMEM;
-+		goto out_free;
-+	}
-+	/* copy current info into new placeholders, incrementing refcnts */
-+	memcpy(tmp_data, UNIONFS_SB(sb)->data,
-+	       cur_branches * sizeof(struct unionfs_data));
-+	memcpy(tmp_lower_paths, UNIONFS_D(sb->s_root)->lower_paths,
-+	       cur_branches * sizeof(struct path));
-+	for (i = 0; i < cur_branches; i++)
-+		path_get(&tmp_lower_paths[i]); /* drop refs at end of fxn */
-+
-+	/*******************************************************************
-+	 * For each branch command, do path_lookup on the requested branch,
-+	 * and apply the change to a temp branch list.  To handle errors, we
-+	 * already dup'ed the old arrays (above), and increased the refcnts
-+	 * on various f/s objects.  So now we can do all the path_lookups
-+	 * and branch-management commands on the new arrays.  If it fail mid
-+	 * way, we free the tmp arrays and *put all objects.  If we succeed,
-+	 * then we free old arrays and *put its objects, and then replace
-+	 * the arrays with the new tmp list (we may have to re-allocate the
-+	 * memory because the temp lists could have been larger than what we
-+	 * actually needed).
-+	 *******************************************************************/
-+
-+	while ((optname = strsep(&options, ",")) != NULL) {
-+		char *optarg;
-+
-+		if (!optname || !*optname)
-+			continue;
-+		/*
-+		 * At this stage optname holds a comma-delimited option, but
-+		 * without the commas.  Next, we need to break the string on
-+		 * the '=' symbol to separate CMD=ARG, where ARG itself can
-+		 * be KEY=VAL.  For example, in mode=/foo=rw, CMD is "mode",
-+		 * KEY is "/foo", and VAL is "rw".
-+		 */
-+		optarg = strchr(optname, '=');
-+		if (optarg)
-+			*optarg++ = '\0';
-+		/* incgen remount option (instead of old ioctl) */
-+		if (!strcmp("incgen", optname)) {
-+			err = 0;
-+			goto out_no_change;
-+		}
-+
-+		/*
-+		 * All of our options take an argument now.  (Insert ones
-+		 * that don't above this check.)  So at this stage optname
-+		 * contains the CMD part and optarg contains the ARG part.
-+		 */
-+		if (!optarg || !*optarg) {
-+			printk(KERN_ERR "unionfs: all remount options require "
-+			       "an argument (%s)\n", optname);
-+			err = -EINVAL;
-+			goto out_release;
-+		}
-+
-+		if (!strcmp("add", optname)) {
-+			err = do_remount_add_option(optarg, new_branches,
-+						    tmp_data,
-+						    tmp_lower_paths,
-+						    &new_high_branch_id);
-+			if (err)
-+				goto out_release;
-+			new_branches++;
-+			if (new_branches > UNIONFS_MAX_BRANCHES) {
-+				printk(KERN_ERR "unionfs: command exceeds "
-+				       "%d branches\n", UNIONFS_MAX_BRANCHES);
-+				err = -E2BIG;
-+				goto out_release;
-+			}
-+			continue;
-+		}
-+		if (!strcmp("del", optname)) {
-+			err = do_remount_del_option(optarg, new_branches,
-+						    tmp_data,
-+						    tmp_lower_paths);
-+			if (err)
-+				goto out_release;
-+			new_branches--;
-+			continue;
-+		}
-+		if (!strcmp("mode", optname)) {
-+			err = do_remount_mode_option(optarg, new_branches,
-+						     tmp_data,
-+						     tmp_lower_paths);
-+			if (err)
-+				goto out_release;
-+			continue;
-+		}
-+
-+		/*
-+		 * When you use "mount -o remount,ro", mount(8) will
-+		 * reportedly pass the original dirs= string from
-+		 * /proc/mounts.  So for now, we have to ignore dirs= and
-+		 * not consider it an error, unless we want to allow users
-+		 * to pass dirs= in remount.  Note that to allow the VFS to
-+		 * actually process the ro/rw remount options, we have to
-+		 * return 0 from this function.
-+		 */
-+		if (!strcmp("dirs", optname)) {
-+			printk(KERN_WARNING
-+			       "unionfs: remount ignoring option \"%s\"\n",
-+			       optname);
-+			continue;
-+		}
-+
-+		err = -EINVAL;
-+		printk(KERN_ERR
-+		       "unionfs: unrecognized option \"%s\"\n", optname);
-+		goto out_release;
-+	}
-+
-+out_no_change:
-+
-+	/******************************************************************
-+	 * WE'RE ALMOST DONE: check if leftmost branch might be read-only,
-+	 * see if we need to allocate a small-sized new vector, copy the
-+	 * vectors to their correct place, release the refcnt of the older
-+	 * ones, and return.  Also handle invalidating any pages that will
-+	 * have to be re-read.
-+	 *******************************************************************/
-+
-+	if (!(tmp_data[0].branchperms & MAY_WRITE)) {
-+		printk(KERN_ERR "unionfs: leftmost branch cannot be read-only "
-+		       "(use \"remount,ro\" to create a read-only union)\n");
-+		err = -EINVAL;
-+		goto out_release;
-+	}
-+
-+	/* (re)allocate space for new pointers to lower dentry */
-+	size = new_branches * sizeof(struct unionfs_data);
-+	new_data = krealloc(tmp_data, size, GFP_KERNEL);
-+	if (unlikely(!new_data)) {
-+		err = -ENOMEM;
-+		goto out_release;
-+	}
-+
-+	/* allocate space for new pointers to lower paths */
-+	size = new_branches * sizeof(struct path);
-+	new_lower_paths = krealloc(tmp_lower_paths, size, GFP_KERNEL);
-+	if (unlikely(!new_lower_paths)) {
-+		err = -ENOMEM;
-+		goto out_release;
-+	}
-+
-+	/* allocate space for new pointers to lower inodes */
-+	new_lower_inodes = kcalloc(new_branches,
-+				   sizeof(struct inode *), GFP_KERNEL);
-+	if (unlikely(!new_lower_inodes)) {
-+		err = -ENOMEM;
-+		goto out_release;
-+	}
-+
-+	/*
-+	 * OK, just before we actually put the new set of branches in place,
-+	 * we need to ensure that our own f/s has no dirty objects left.
-+	 * Luckily, do_remount_sb() already calls shrink_dcache_sb(sb) and
-+	 * fsync_super(sb), taking care of dentries, inodes, and dirty
-+	 * pages.  So all that's left is for us to invalidate any leftover
-+	 * (non-dirty) pages to ensure that they will be re-read from the
-+	 * new lower branches (and to support mmap).
-+	 */
-+
-+	/*
-+	 * Once we finish the remounting successfully, our superblock
-+	 * generation number will have increased.  This will be detected by
-+	 * our dentry-revalidation code upon subsequent f/s operations
-+	 * through unionfs.  The revalidation code will rebuild the union of
-+	 * lower inodes for a given unionfs inode and invalidate any pages
-+	 * of such "stale" inodes (by calling our purge_inode_data
-+	 * function).  This revalidation will happen lazily and
-+	 * incrementally, as users perform operations on cached inodes.  We
-+	 * would like to encourage this revalidation to happen sooner if
-+	 * possible, so we like to try to invalidate as many other pages in
-+	 * our superblock as we can.  We used to call drop_pagecache_sb() or
-+	 * a variant thereof, but either method was racy (drop_caches alone
-+	 * is known to be racy).  So now we let the revalidation happen on a
-+	 * per file basis in ->d_revalidate.
-+	 */
-+
-+	/* grab new lower super references; release old ones */
-+	for (i = 0; i < new_branches; i++)
-+		atomic_inc(&new_data[i].sb->s_active);
-+	for (i = 0; i < sbmax(sb); i++)
-+		atomic_dec(&UNIONFS_SB(sb)->data[i].sb->s_active);
-+
-+	/* copy new vectors into their correct place */
-+	tmp_data = UNIONFS_SB(sb)->data;
-+	UNIONFS_SB(sb)->data = new_data;
-+	new_data = NULL;	/* so don't free good pointers below */
-+	tmp_lower_paths = UNIONFS_D(sb->s_root)->lower_paths;
-+	UNIONFS_D(sb->s_root)->lower_paths = new_lower_paths;
-+	new_lower_paths = NULL;	/* so don't free good pointers below */
-+
-+	/* update our unionfs_sb_info and root dentry index of last branch */
-+	i = sbmax(sb);		/* save no. of branches to release at end */
-+	sbend(sb) = new_branches - 1;
-+	dbend(sb->s_root) = new_branches - 1;
-+	old_ibstart = ibstart(sb->s_root->d_inode);
-+	old_ibend = ibend(sb->s_root->d_inode);
-+	ibend(sb->s_root->d_inode) = new_branches - 1;
-+	UNIONFS_D(sb->s_root)->bcount = new_branches;
-+	new_branches = i; /* no. of branches to release below */
-+
-+	/*
-+	 * Update lower inodes: 3 steps
-+	 * 1. grab ref on all new lower inodes
-+	 */
-+	for (i = dbstart(sb->s_root); i <= dbend(sb->s_root); i++) {
-+		struct dentry *lower_dentry =
-+			unionfs_lower_dentry_idx(sb->s_root, i);
-+		igrab(lower_dentry->d_inode);
-+		new_lower_inodes[i] = lower_dentry->d_inode;
-+	}
-+	/* 2. release reference on all older lower inodes */
-+	iput_lowers(sb->s_root->d_inode, old_ibstart, old_ibend, true);
-+	/* 3. update root dentry's inode to new lower_inodes array */
-+	UNIONFS_I(sb->s_root->d_inode)->lower_inodes = new_lower_inodes;
-+	new_lower_inodes = NULL;
-+
-+	/* maxbytes may have changed */
-+	sb->s_maxbytes = unionfs_lower_super_idx(sb, 0)->s_maxbytes;
-+	/* update high branch ID */
-+	sbhbid(sb) = new_high_branch_id;
-+
-+	/* update our sb->generation for revalidating objects */
-+	i = atomic_inc_return(&UNIONFS_SB(sb)->generation);
-+	atomic_set(&UNIONFS_D(sb->s_root)->generation, i);
-+	atomic_set(&UNIONFS_I(sb->s_root->d_inode)->generation, i);
-+	if (!(*flags & MS_SILENT))
-+		pr_info("unionfs: %s: new generation number %d\n",
-+			UNIONFS_SB(sb)->dev_name, i);
-+	/* finally, update the root dentry's times */
-+	unionfs_copy_attr_times(sb->s_root->d_inode);
-+	err = 0;		/* reset to success */
-+
-+	/*
-+	 * The code above falls through to the next label, and releases the
-+	 * refcnts of the older ones (stored in tmp_*): if we fell through
-+	 * here, it means success.  However, if we jump directly to this
-+	 * label from any error above, then an error occurred after we
-+	 * grabbed various refcnts, and so we have to release the
-+	 * temporarily constructed structures.
-+	 */
-+out_release:
-+	/* no need to cleanup/release anything in tmp_data */
-+	if (tmp_lower_paths)
-+		for (i = 0; i < new_branches; i++)
-+			path_put(&tmp_lower_paths[i]);
-+out_free:
-+	kfree(tmp_lower_paths);
-+	kfree(tmp_data);
-+	kfree(new_lower_paths);
-+	kfree(new_data);
-+	kfree(new_lower_inodes);
-+out_error:
-+	unionfs_check_dentry(sb->s_root);
-+	unionfs_write_unlock(sb);
-+	return err;
-+}
-+
-+/*
-+ * Called by iput() when the inode reference count reached zero
-+ * and the inode is not hashed anywhere.  Used to clear anything
-+ * that needs to be, before the inode is completely destroyed and put
-+ * on the inode free list.
-+ *
-+ * No need to lock sb info's rwsem.
-+ */
-+static void unionfs_clear_inode(struct inode *inode)
-+{
-+	int bindex, bstart, bend;
-+	struct inode *lower_inode;
-+	struct list_head *pos, *n;
-+	struct unionfs_dir_state *rdstate;
-+
-+	list_for_each_safe(pos, n, &UNIONFS_I(inode)->readdircache) {
-+		rdstate = list_entry(pos, struct unionfs_dir_state, cache);
-+		list_del(&rdstate->cache);
-+		free_rdstate(rdstate);
-+	}
-+
-+	/*
-+	 * Decrement a reference to a lower_inode, which was incremented
-+	 * by our read_inode when it was created initially.
-+	 */
-+	bstart = ibstart(inode);
-+	bend = ibend(inode);
-+	if (bstart >= 0) {
-+		for (bindex = bstart; bindex <= bend; bindex++) {
-+			lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+			if (!lower_inode)
-+				continue;
-+			unionfs_set_lower_inode_idx(inode, bindex, NULL);
-+			/* see Documentation/filesystems/unionfs/issues.txt */
-+			lockdep_off();
-+			iput(lower_inode);
-+			lockdep_on();
-+		}
-+	}
-+
-+	kfree(UNIONFS_I(inode)->lower_inodes);
-+	UNIONFS_I(inode)->lower_inodes = NULL;
-+}
-+
-+static struct inode *unionfs_alloc_inode(struct super_block *sb)
-+{
-+	struct unionfs_inode_info *i;
-+
-+	i = kmem_cache_alloc(unionfs_inode_cachep, GFP_KERNEL);
-+	if (unlikely(!i))
-+		return NULL;
-+
-+	/* memset everything up to the inode to 0 */
-+	memset(i, 0, offsetof(struct unionfs_inode_info, vfs_inode));
-+
-+	i->vfs_inode.i_version = 1;
-+	return &i->vfs_inode;
-+}
-+
-+static void unionfs_destroy_inode(struct inode *inode)
-+{
-+	kmem_cache_free(unionfs_inode_cachep, UNIONFS_I(inode));
-+}
-+
-+/* unionfs inode cache constructor */
-+static void init_once(void *obj)
-+{
-+	struct unionfs_inode_info *i = obj;
-+
-+	inode_init_once(&i->vfs_inode);
-+}
-+
-+int unionfs_init_inode_cache(void)
-+{
-+	int err = 0;
-+
-+	unionfs_inode_cachep =
-+		kmem_cache_create("unionfs_inode_cache",
-+				  sizeof(struct unionfs_inode_info), 0,
-+				  SLAB_RECLAIM_ACCOUNT, init_once);
-+	if (unlikely(!unionfs_inode_cachep))
-+		err = -ENOMEM;
-+	return err;
-+}
-+
-+/* unionfs inode cache destructor */
-+void unionfs_destroy_inode_cache(void)
-+{
-+	if (unionfs_inode_cachep)
-+		kmem_cache_destroy(unionfs_inode_cachep);
-+}
-+
-+/*
-+ * Called when we have a dirty inode, right here we only throw out
-+ * parts of our readdir list that are too old.
-+ *
-+ * No need to grab sb info's rwsem.
-+ */
-+static int unionfs_write_inode(struct inode *inode, int sync)
-+{
-+	struct list_head *pos, *n;
-+	struct unionfs_dir_state *rdstate;
-+
-+	spin_lock(&UNIONFS_I(inode)->rdlock);
-+	list_for_each_safe(pos, n, &UNIONFS_I(inode)->readdircache) {
-+		rdstate = list_entry(pos, struct unionfs_dir_state, cache);
-+		/* We keep this list in LRU order. */
-+		if ((rdstate->access + RDCACHE_JIFFIES) > jiffies)
-+			break;
-+		UNIONFS_I(inode)->rdcount--;
-+		list_del(&rdstate->cache);
-+		free_rdstate(rdstate);
-+	}
-+	spin_unlock(&UNIONFS_I(inode)->rdlock);
-+
-+	return 0;
-+}
-+
-+/*
-+ * Used only in nfs, to kill any pending RPC tasks, so that subsequent
-+ * code can actually succeed and won't leave tasks that need handling.
-+ */
-+static void unionfs_umount_begin(struct super_block *sb)
-+{
-+	struct super_block *lower_sb;
-+	int bindex, bstart, bend;
-+
-+	unionfs_read_lock(sb, UNIONFS_SMUTEX_CHILD);
-+
-+	bstart = sbstart(sb);
-+	bend = sbend(sb);
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_sb = unionfs_lower_super_idx(sb, bindex);
-+
-+		if (lower_sb && lower_sb->s_op &&
-+		    lower_sb->s_op->umount_begin)
-+			lower_sb->s_op->umount_begin(lower_sb);
-+	}
-+
-+	unionfs_read_unlock(sb);
-+}
-+
-+static int unionfs_show_options(struct seq_file *m, struct vfsmount *mnt)
-+{
-+	struct super_block *sb = mnt->mnt_sb;
-+	int ret = 0;
-+	char *tmp_page;
-+	char *path;
-+	int bindex, bstart, bend;
-+	int perms;
-+
-+	unionfs_read_lock(sb, UNIONFS_SMUTEX_CHILD);
-+
-+	unionfs_lock_dentry(sb->s_root, UNIONFS_DMUTEX_CHILD);
-+
-+	tmp_page = (char *) __get_free_page(GFP_KERNEL);
-+	if (unlikely(!tmp_page)) {
-+		ret = -ENOMEM;
-+		goto out;
-+	}
-+
-+	bstart = sbstart(sb);
-+	bend = sbend(sb);
-+
-+	seq_printf(m, ",dirs=");
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		struct path p;
-+		p.dentry = unionfs_lower_dentry_idx(sb->s_root, bindex);
-+		p.mnt = unionfs_lower_mnt_idx(sb->s_root, bindex);
-+		path = d_path(&p, tmp_page, PAGE_SIZE);
-+		if (IS_ERR(path)) {
-+			ret = PTR_ERR(path);
-+			goto out;
-+		}
-+
-+		perms = branchperms(sb, bindex);
-+
-+		seq_printf(m, "%s=%s", path,
-+			   perms & MAY_WRITE ? "rw" : "ro");
-+		if (bindex != bend)
-+			seq_printf(m, ":");
-+	}
-+
-+out:
-+	free_page((unsigned long) tmp_page);
-+
-+	unionfs_unlock_dentry(sb->s_root);
-+
-+	unionfs_read_unlock(sb);
-+
-+	return ret;
-+}
-+
-+struct super_operations unionfs_sops = {
-+	.delete_inode	= unionfs_delete_inode,
-+	.put_super	= unionfs_put_super,
-+	.statfs		= unionfs_statfs,
-+	.remount_fs	= unionfs_remount_fs,
-+	.clear_inode	= unionfs_clear_inode,
-+	.umount_begin	= unionfs_umount_begin,
-+	.show_options	= unionfs_show_options,
-+	.write_inode	= unionfs_write_inode,
-+	.alloc_inode	= unionfs_alloc_inode,
-+	.destroy_inode	= unionfs_destroy_inode,
-+};
-diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
-new file mode 100644
-index 0000000..1b9c3f7
---- /dev/null
-+++ b/fs/unionfs/union.h
-@@ -0,0 +1,607 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#ifndef _UNION_H_
-+#define _UNION_H_
-+
-+#include <linux/dcache.h>
-+#include <linux/file.h>
-+#include <linux/list.h>
-+#include <linux/fs.h>
-+#include <linux/mm.h>
-+#include <linux/module.h>
-+#include <linux/mount.h>
-+#include <linux/namei.h>
-+#include <linux/page-flags.h>
-+#include <linux/pagemap.h>
-+#include <linux/poll.h>
-+#include <linux/security.h>
-+#include <linux/seq_file.h>
-+#include <linux/slab.h>
-+#include <linux/spinlock.h>
-+#include <linux/smp_lock.h>
-+#include <linux/statfs.h>
-+#include <linux/string.h>
-+#include <linux/vmalloc.h>
-+#include <linux/writeback.h>
-+#include <linux/buffer_head.h>
-+#include <linux/xattr.h>
-+#include <linux/fs_stack.h>
-+#include <linux/magic.h>
-+#include <linux/log2.h>
-+#include <linux/poison.h>
-+#include <linux/mman.h>
-+#include <linux/backing-dev.h>
-+#include <linux/splice.h>
-+
-+#include <asm/system.h>
-+
-+#include <linux/union_fs.h>
-+
-+/* the file system name */
-+#define UNIONFS_NAME "unionfs"
-+
-+/* unionfs root inode number */
-+#define UNIONFS_ROOT_INO     1
-+
-+/* number of times we try to get a unique temporary file name */
-+#define GET_TMPNAM_MAX_RETRY	5
-+
-+/* maximum number of branches we support, to avoid memory blowup */
-+#define UNIONFS_MAX_BRANCHES	128
-+
-+/* minimum time (seconds) required for time-based cache-coherency */
-+#define UNIONFS_MIN_CC_TIME	3
-+
-+/* Operations vectors defined in specific files. */
-+extern struct file_operations unionfs_main_fops;
-+extern struct file_operations unionfs_dir_fops;
-+extern struct inode_operations unionfs_main_iops;
-+extern struct inode_operations unionfs_dir_iops;
-+extern struct inode_operations unionfs_symlink_iops;
-+extern struct super_operations unionfs_sops;
-+extern struct dentry_operations unionfs_dops;
-+extern struct address_space_operations unionfs_aops, unionfs_dummy_aops;
-+extern struct vm_operations_struct unionfs_vm_ops;
-+
-+/* How long should an entry be allowed to persist */
-+#define RDCACHE_JIFFIES	(5*HZ)
-+
-+/* compatibility with Real-Time patches */
-+#ifdef CONFIG_PREEMPT_RT
-+# define unionfs_rw_semaphore	compat_rw_semaphore
-+#else /* not CONFIG_PREEMPT_RT */
-+# define unionfs_rw_semaphore	rw_semaphore
-+#endif /* not CONFIG_PREEMPT_RT */
-+
-+/* file private data. */
-+struct unionfs_file_info {
-+	int bstart;
-+	int bend;
-+	atomic_t generation;
-+
-+	struct unionfs_dir_state *rdstate;
-+	struct file **lower_files;
-+	int *saved_branch_ids; /* IDs of branches when file was opened */
-+	struct vm_operations_struct *lower_vm_ops;
-+	bool wrote_to_file;	/* for delayed copyup */
-+};
-+
-+/* unionfs inode data in memory */
-+struct unionfs_inode_info {
-+	int bstart;
-+	int bend;
-+	atomic_t generation;
-+	/* Stuff for readdir over NFS. */
-+	spinlock_t rdlock;
-+	struct list_head readdircache;
-+	int rdcount;
-+	int hashsize;
-+	int cookie;
-+
-+	/* The lower inodes */
-+	struct inode **lower_inodes;
-+
-+	struct inode vfs_inode;
-+};
-+
-+/* unionfs dentry data in memory */
-+struct unionfs_dentry_info {
-+	/*
-+	 * The semaphore is used to lock the dentry as soon as we get into a
-+	 * unionfs function from the VFS.  Our lock ordering is that children
-+	 * go before their parents.
-+	 */
-+	struct mutex lock;
-+	int bstart;
-+	int bend;
-+	int bopaque;
-+	int bcount;
-+	atomic_t generation;
-+	struct path *lower_paths;
-+};
-+
-+/* These are the pointers to our various objects. */
-+struct unionfs_data {
-+	struct super_block *sb;	/* lower super_block */
-+	atomic_t open_files;	/* number of open files on branch */
-+	int branchperms;
-+	int branch_id;		/* unique branch ID at re/mount time */
-+};
-+
-+/* unionfs super-block data in memory */
-+struct unionfs_sb_info {
-+	int bend;
-+
-+	atomic_t generation;
-+
-+	/*
-+	 * This rwsem is used to make sure that a branch management
-+	 * operation...
-+	 *   1) will not begin before all currently in-flight operations
-+	 *      complete.
-+	 *   2) any new operations do not execute until the currently
-+	 *      running branch management operation completes.
-+	 *
-+	 * The write_lock_owner records the PID of the task which grabbed
-+	 * the rw_sem for writing.  If the same task also tries to grab the
-+	 * read lock, we allow it.  This prevents a self-deadlock when
-+	 * branch-management is used on a pivot_root'ed union, because we
-+	 * have to ->lookup paths which belong to the same union.
-+	 */
-+	struct unionfs_rw_semaphore rwsem;
-+	pid_t write_lock_owner;	/* PID of rw_sem owner (write lock) */
-+	int high_branch_id;	/* last unique branch ID given */
-+	char *dev_name;		/* to identify different unions in pr_debug */
-+	struct unionfs_data *data;
-+};
-+
-+/*
-+ * structure for making the linked list of entries by readdir on left branch
-+ * to compare with entries on right branch
-+ */
-+struct filldir_node {
-+	struct list_head file_list;	/* list for directory entries */
-+	char *name;		/* name entry */
-+	int hash;		/* name hash */
-+	int namelen;		/* name len since name is not 0 terminated */
-+
-+	/*
-+	 * we can check for duplicate whiteouts and files in the same branch
-+	 * in order to return -EIO.
-+	 */
-+	int bindex;
-+
-+	/* is this a whiteout entry? */
-+	int whiteout;
-+
-+	/* Inline name, so we don't need to separately kmalloc small ones */
-+	char iname[DNAME_INLINE_LEN_MIN];
-+};
-+
-+/* Directory hash table. */
-+struct unionfs_dir_state {
-+	unsigned int cookie;	/* the cookie, based off of rdversion */
-+	unsigned int offset;	/* The entry we have returned. */
-+	int bindex;
-+	loff_t dirpos;		/* offset within the lower level directory */
-+	int size;		/* How big is the hash table? */
-+	int hashentries;	/* How many entries have been inserted? */
-+	unsigned long access;
-+
-+	/* This cache list is used when the inode keeps us around. */
-+	struct list_head cache;
-+	struct list_head list[0];
-+};
-+
-+/* externs needed for fanout.h or sioq.h */
-+extern int unionfs_get_nlinks(const struct inode *inode);
-+extern void unionfs_copy_attr_times(struct inode *upper);
-+extern void unionfs_copy_attr_all(struct inode *dest, const struct inode *src);
-+
-+/* include miscellaneous macros */
-+#include "fanout.h"
-+#include "sioq.h"
-+
-+/* externs for cache creation/deletion routines */
-+extern void unionfs_destroy_filldir_cache(void);
-+extern int unionfs_init_filldir_cache(void);
-+extern int unionfs_init_inode_cache(void);
-+extern void unionfs_destroy_inode_cache(void);
-+extern int unionfs_init_dentry_cache(void);
-+extern void unionfs_destroy_dentry_cache(void);
-+
-+/* Initialize and free readdir-specific  state. */
-+extern int init_rdstate(struct file *file);
-+extern struct unionfs_dir_state *alloc_rdstate(struct inode *inode,
-+					       int bindex);
-+extern struct unionfs_dir_state *find_rdstate(struct inode *inode,
-+					      loff_t fpos);
-+extern void free_rdstate(struct unionfs_dir_state *state);
-+extern int add_filldir_node(struct unionfs_dir_state *rdstate,
-+			    const char *name, int namelen, int bindex,
-+			    int whiteout);
-+extern struct filldir_node *find_filldir_node(struct unionfs_dir_state *rdstate,
-+					      const char *name, int namelen,
-+					      int is_whiteout);
-+
-+extern struct dentry **alloc_new_dentries(int objs);
-+extern struct unionfs_data *alloc_new_data(int objs);
-+
-+/* We can only use 32-bits of offset for rdstate --- blech! */
-+#define DIREOF (0xfffff)
-+#define RDOFFBITS 20		/* This is the number of bits in DIREOF. */
-+#define MAXRDCOOKIE (0xfff)
-+/* Turn an rdstate into an offset. */
-+static inline off_t rdstate2offset(struct unionfs_dir_state *buf)
-+{
-+	off_t tmp;
-+
-+	tmp = ((buf->cookie & MAXRDCOOKIE) << RDOFFBITS)
-+		| (buf->offset & DIREOF);
-+	return tmp;
-+}
-+
-+/* Macros for locking a super_block. */
-+enum unionfs_super_lock_class {
-+	UNIONFS_SMUTEX_NORMAL,
-+	UNIONFS_SMUTEX_PARENT,	/* when locking on behalf of file */
-+	UNIONFS_SMUTEX_CHILD,	/* when locking on behalf of dentry */
-+};
-+static inline void unionfs_read_lock(struct super_block *sb, int subclass)
-+{
-+	if (UNIONFS_SB(sb)->write_lock_owner &&
-+	    UNIONFS_SB(sb)->write_lock_owner == current->pid)
-+		return;
-+	down_read_nested(&UNIONFS_SB(sb)->rwsem, subclass);
-+}
-+static inline void unionfs_read_unlock(struct super_block *sb)
-+{
-+	if (UNIONFS_SB(sb)->write_lock_owner &&
-+	    UNIONFS_SB(sb)->write_lock_owner == current->pid)
-+		return;
-+	up_read(&UNIONFS_SB(sb)->rwsem);
-+}
-+static inline void unionfs_write_lock(struct super_block *sb)
-+{
-+	down_write(&UNIONFS_SB(sb)->rwsem);
-+	UNIONFS_SB(sb)->write_lock_owner = current->pid;
-+}
-+static inline void unionfs_write_unlock(struct super_block *sb)
-+{
-+	up_write(&UNIONFS_SB(sb)->rwsem);
-+	UNIONFS_SB(sb)->write_lock_owner = 0;
-+}
-+
-+static inline void unionfs_double_lock_dentry(struct dentry *d1,
-+					      struct dentry *d2)
-+{
-+	BUG_ON(d1 == d2);
-+	if (d1 < d2) {
-+		unionfs_lock_dentry(d2, UNIONFS_DMUTEX_CHILD);
-+		unionfs_lock_dentry(d1, UNIONFS_DMUTEX_PARENT);
-+	} else {
-+		unionfs_lock_dentry(d1, UNIONFS_DMUTEX_CHILD);
-+		unionfs_lock_dentry(d2, UNIONFS_DMUTEX_PARENT);
-+	}
-+}
-+
-+extern int new_dentry_private_data(struct dentry *dentry, int subclass);
-+extern int realloc_dentry_private_data(struct dentry *dentry);
-+extern void free_dentry_private_data(struct dentry *dentry);
-+extern void update_bstart(struct dentry *dentry);
-+extern int init_lower_nd(struct nameidata *nd, unsigned int flags);
-+extern void release_lower_nd(struct nameidata *nd, int err);
-+
-+/*
-+ * EXTERNALS:
-+ */
-+
-+/* replicates the directory structure up to given dentry in given branch */
-+extern struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
-+				     const char *name, int bindex);
-+
-+/* partial lookup */
-+extern int unionfs_partial_lookup(struct dentry *dentry);
-+extern struct dentry *unionfs_lookup_full(struct dentry *dentry,
-+					  struct nameidata *nd_unused,
-+					  int lookupmode);
-+
-+/* copies a file from dbstart to newbindex branch */
-+extern int copyup_file(struct inode *dir, struct file *file, int bstart,
-+		       int newbindex, loff_t size);
-+extern int copyup_named_file(struct inode *dir, struct file *file,
-+			     char *name, int bstart, int new_bindex,
-+			     loff_t len);
-+/* copies a dentry from dbstart to newbindex branch */
-+extern int copyup_dentry(struct inode *dir, struct dentry *dentry,
-+			 int bstart, int new_bindex, const char *name,
-+			 int namelen, struct file **copyup_file, loff_t len);
-+/* helper functions for post-copyup actions */
-+extern void unionfs_postcopyup_setmnt(struct dentry *dentry);
-+extern void unionfs_postcopyup_release(struct dentry *dentry);
-+
-+/* Is this directory empty: 0 if it is empty, -ENOTEMPTY if not. */
-+extern int check_empty(struct dentry *dentry,
-+		       struct unionfs_dir_state **namelist);
-+/* whiteout and opaque directory helpers */
-+extern char *alloc_whname(const char *name, int len);
-+extern bool is_whiteout_name(char **namep, int *namelenp);
-+extern bool is_validname(const char *name);
-+extern struct dentry *lookup_whiteout(const char *name,
-+				      struct dentry *lower_parent);
-+extern struct dentry *find_first_whiteout(struct dentry *dentry);
-+extern int unlink_whiteout(struct dentry *wh_dentry);
-+extern int check_unlink_whiteout(struct dentry *dentry,
-+				 struct dentry *lower_dentry, int bindex);
-+extern int create_whiteout(struct dentry *dentry, int start);
-+extern int delete_whiteouts(struct dentry *dentry, int bindex,
-+			    struct unionfs_dir_state *namelist);
-+extern int is_opaque_dir(struct dentry *dentry, int bindex);
-+extern int make_dir_opaque(struct dentry *dir, int bindex);
-+extern void unionfs_set_max_namelen(long *namelen);
-+
-+extern void unionfs_reinterpose(struct dentry *this_dentry);
-+extern struct super_block *unionfs_duplicate_super(struct super_block *sb);
-+
-+/* Locking functions. */
-+extern int unionfs_setlk(struct file *file, int cmd, struct file_lock *fl);
-+extern int unionfs_getlk(struct file *file, struct file_lock *fl);
-+
-+/* Common file operations. */
-+extern int unionfs_file_revalidate(struct file *file, bool willwrite);
-+extern int unionfs_file_revalidate_locked(struct file *file, bool willwrite);
-+extern int unionfs_open(struct inode *inode, struct file *file);
-+extern int unionfs_file_release(struct inode *inode, struct file *file);
-+extern int unionfs_flush(struct file *file, fl_owner_t id);
-+extern long unionfs_ioctl(struct file *file, unsigned int cmd,
-+			  unsigned long arg);
-+extern int unionfs_fsync(struct file *file, struct dentry *dentry,
-+			 int datasync);
-+extern int unionfs_fasync(int fd, struct file *file, int flag);
-+
-+/* Inode operations */
-+extern struct inode *unionfs_iget(struct super_block *sb, unsigned long ino);
-+extern int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-+			  struct inode *new_dir, struct dentry *new_dentry);
-+extern int unionfs_unlink(struct inode *dir, struct dentry *dentry);
-+extern int unionfs_rmdir(struct inode *dir, struct dentry *dentry);
-+
-+extern bool __unionfs_d_revalidate_one_locked(struct dentry *dentry,
-+					      struct nameidata *nd,
-+					      bool willwrite);
-+extern bool __unionfs_d_revalidate_chain(struct dentry *dentry,
-+					 struct nameidata *nd, bool willwrite);
-+extern bool is_negative_lower(const struct dentry *dentry);
-+extern bool is_newer_lower(const struct dentry *dentry);
-+extern void purge_sb_data(struct super_block *sb);
-+
-+/* The values for unionfs_interpose's flag. */
-+#define INTERPOSE_DEFAULT	0
-+#define INTERPOSE_LOOKUP	1
-+#define INTERPOSE_REVAL		2
-+#define INTERPOSE_REVAL_NEG	3
-+#define INTERPOSE_PARTIAL	4
-+
-+extern struct dentry *unionfs_interpose(struct dentry *this_dentry,
-+					struct super_block *sb, int flag);
-+
-+#ifdef CONFIG_UNION_FS_XATTR
-+/* Extended attribute functions. */
-+extern void *unionfs_xattr_alloc(size_t size, size_t limit);
-+static inline void unionfs_xattr_kfree(const void *p)
-+{
-+	kfree(p);
-+}
-+extern ssize_t unionfs_getxattr(struct dentry *dentry, const char *name,
-+				void *value, size_t size);
-+extern int unionfs_removexattr(struct dentry *dentry, const char *name);
-+extern ssize_t unionfs_listxattr(struct dentry *dentry, char *list,
-+				 size_t size);
-+extern int unionfs_setxattr(struct dentry *dentry, const char *name,
-+			    const void *value, size_t size, int flags);
-+#endif /* CONFIG_UNION_FS_XATTR */
-+
-+/* The root directory is unhashed, but isn't deleted. */
-+static inline int d_deleted(struct dentry *d)
-+{
-+	return d_unhashed(d) && (d != d->d_sb->s_root);
-+}
-+
-+/* unionfs_permission, check if we should bypass error to facilitate copyup */
-+#define IS_COPYUP_ERR(err) ((err) == -EROFS)
-+
-+/* unionfs_open, check if we need to copyup the file */
-+#define OPEN_WRITE_FLAGS (O_WRONLY | O_RDWR | O_APPEND)
-+#define IS_WRITE_FLAG(flag) ((flag) & OPEN_WRITE_FLAGS)
-+
-+static inline int branchperms(const struct super_block *sb, int index)
-+{
-+	BUG_ON(index < 0);
-+	return UNIONFS_SB(sb)->data[index].branchperms;
-+}
-+
-+static inline int set_branchperms(struct super_block *sb, int index, int perms)
-+{
-+	BUG_ON(index < 0);
-+	UNIONFS_SB(sb)->data[index].branchperms = perms;
-+	return perms;
-+}
-+
-+/* Is this file on a read-only branch? */
-+static inline int is_robranch_super(const struct super_block *sb, int index)
-+{
-+	int ret;
-+
-+	ret = (!(branchperms(sb, index) & MAY_WRITE)) ? -EROFS : 0;
-+	return ret;
-+}
-+
-+/* Is this file on a read-only branch? */
-+static inline int is_robranch_idx(const struct dentry *dentry, int index)
-+{
-+	struct super_block *lower_sb;
-+
-+	BUG_ON(index < 0);
-+
-+	if (!(branchperms(dentry->d_sb, index) & MAY_WRITE))
-+		return -EROFS;
-+
-+	lower_sb = unionfs_lower_super_idx(dentry->d_sb, index);
-+	BUG_ON(lower_sb == NULL);
-+	/*
-+	 * test sb flags directly, not IS_RDONLY(lower_inode) because the
-+	 * lower_dentry could be a negative.
-+	 */
-+	if (lower_sb->s_flags & MS_RDONLY)
-+		return -EROFS;
-+
-+	return 0;
-+}
-+
-+static inline int is_robranch(const struct dentry *dentry)
-+{
-+	int index;
-+
-+	index = UNIONFS_D(dentry)->bstart;
-+	BUG_ON(index < 0);
-+
-+	return is_robranch_idx(dentry, index);
-+}
-+
-+/*
-+ * EXTERNALS:
-+ */
-+extern int check_branch(struct nameidata *nd);
-+extern int parse_branch_mode(const char *name, int *perms);
-+
-+/* locking helpers */
-+static inline struct dentry *lock_parent(struct dentry *dentry)
-+{
-+	struct dentry *dir = dget_parent(dentry);
-+	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
-+	return dir;
-+}
-+static inline struct dentry *lock_parent_wh(struct dentry *dentry)
-+{
-+	struct dentry *dir = dget_parent(dentry);
-+
-+	mutex_lock_nested(&dir->d_inode->i_mutex, UNIONFS_DMUTEX_WHITEOUT);
-+	return dir;
-+}
-+
-+static inline void unlock_dir(struct dentry *dir)
-+{
-+	mutex_unlock(&dir->d_inode->i_mutex);
-+	dput(dir);
-+}
-+
-+static inline struct vfsmount *unionfs_mntget(struct dentry *dentry,
-+					      int bindex)
-+{
-+	struct vfsmount *mnt;
-+
-+	BUG_ON(!dentry || bindex < 0);
-+
-+	mnt = mntget(unionfs_lower_mnt_idx(dentry, bindex));
-+#ifdef CONFIG_UNION_FS_DEBUG
-+	if (!mnt)
-+		pr_debug("unionfs: mntget: mnt=%p bindex=%d\n",
-+			 mnt, bindex);
-+#endif /* CONFIG_UNION_FS_DEBUG */
-+
-+	return mnt;
-+}
-+
-+static inline void unionfs_mntput(struct dentry *dentry, int bindex)
-+{
-+	struct vfsmount *mnt;
-+
-+	if (!dentry && bindex < 0)
-+		return;
-+	BUG_ON(!dentry || bindex < 0);
-+
-+	mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+#ifdef CONFIG_UNION_FS_DEBUG
-+	/*
-+	 * Directories can have NULL lower objects in between start/end, but
-+	 * NOT if at the start/end range.  We cannot verify that this dentry
-+	 * is a type=DIR, because it may already be a negative dentry.  But
-+	 * if dbstart is greater than dbend, we know that this couldn't have
-+	 * been a regular file: it had to have been a directory.
-+	 */
-+	if (!mnt && !(bindex > dbstart(dentry) && bindex < dbend(dentry)))
-+		pr_debug("unionfs: mntput: mnt=%p bindex=%d\n", mnt, bindex);
-+#endif /* CONFIG_UNION_FS_DEBUG */
-+	mntput(mnt);
-+}
-+
-+#ifdef CONFIG_UNION_FS_DEBUG
-+
-+/* useful for tracking code reachability */
-+#define UDBG pr_debug("DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)
-+
-+#define unionfs_check_inode(i)	__unionfs_check_inode((i),	\
-+	__FILE__, __func__, __LINE__)
-+#define unionfs_check_dentry(d)	__unionfs_check_dentry((d),	\
-+	__FILE__, __func__, __LINE__)
-+#define unionfs_check_file(f)	__unionfs_check_file((f),	\
-+	__FILE__, __func__, __LINE__)
-+#define unionfs_check_nd(n)	__unionfs_check_nd((n),		\
-+	__FILE__, __func__, __LINE__)
-+#define show_branch_counts(sb)	__show_branch_counts((sb),	\
-+	__FILE__, __func__, __LINE__)
-+#define show_inode_times(i)	__show_inode_times((i),		\
-+	__FILE__, __func__, __LINE__)
-+#define show_dinode_times(d)	__show_dinode_times((d),	\
-+	__FILE__, __func__, __LINE__)
-+#define show_inode_counts(i)	__show_inode_counts((i),	\
-+	__FILE__, __func__, __LINE__)
-+
-+extern void __unionfs_check_inode(const struct inode *inode, const char *fname,
-+				  const char *fxn, int line);
-+extern void __unionfs_check_dentry(const struct dentry *dentry,
-+				   const char *fname, const char *fxn,
-+				   int line);
-+extern void __unionfs_check_file(const struct file *file,
-+				 const char *fname, const char *fxn, int line);
-+extern void __unionfs_check_nd(const struct nameidata *nd,
-+			       const char *fname, const char *fxn, int line);
-+extern void __show_branch_counts(const struct super_block *sb,
-+				 const char *file, const char *fxn, int line);
-+extern void __show_inode_times(const struct inode *inode,
-+			       const char *file, const char *fxn, int line);
-+extern void __show_dinode_times(const struct dentry *dentry,
-+				const char *file, const char *fxn, int line);
-+extern void __show_inode_counts(const struct inode *inode,
-+				const char *file, const char *fxn, int line);
-+
-+#else /* not CONFIG_UNION_FS_DEBUG */
-+
-+/* we leave useful hooks for these check functions throughout the code */
-+#define unionfs_check_inode(i)		do { } while (0)
-+#define unionfs_check_dentry(d)		do { } while (0)
-+#define unionfs_check_file(f)		do { } while (0)
-+#define unionfs_check_nd(n)		do { } while (0)
-+#define show_branch_counts(sb)		do { } while (0)
-+#define show_inode_times(i)		do { } while (0)
-+#define show_dinode_times(d)		do { } while (0)
-+#define show_inode_counts(i)		do { } while (0)
-+
-+#endif /* not CONFIG_UNION_FS_DEBUG */
-+
-+#endif	/* not _UNION_H_ */
-diff --git a/fs/unionfs/unlink.c b/fs/unionfs/unlink.c
-new file mode 100644
-index 0000000..623f68d
---- /dev/null
-+++ b/fs/unionfs/unlink.c
-@@ -0,0 +1,277 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Helper function for Unionfs's unlink operation.
-+ *
-+ * The main goal of this function is to optimize the unlinking of non-dir
-+ * objects in unionfs by deleting all possible lower inode objects from the
-+ * underlying branches having same dentry name as the non-dir dentry on
-+ * which this unlink operation is called.  This way we delete as many lower
-+ * inodes as possible, and save space.  Whiteouts need to be created in
-+ * branch0 only if unlinking fails on any of the lower branch other than
-+ * branch0, or if a lower branch is marked read-only.
-+ *
-+ * Also, while unlinking a file, if we encounter any dir type entry in any
-+ * intermediate branch, then we remove the directory by calling vfs_rmdir.
-+ * The following special cases are also handled:
-+
-+ * (1) If an error occurs in branch0 during vfs_unlink, then we return
-+ *     appropriate error.
-+ *
-+ * (2) If we get an error during unlink in any of other lower branch other
-+ *     than branch0, then we create a whiteout in branch0.
-+ *
-+ * (3) If a whiteout already exists in any intermediate branch, we delete
-+ *     all possible inodes only up to that branch (this is an "opaqueness"
-+ *     as as per Documentation/filesystems/unionfs/concepts.txt).
-+ *
-+ */
-+static int unionfs_unlink_whiteout(struct inode *dir, struct dentry *dentry)
-+{
-+	struct dentry *lower_dentry;
-+	struct dentry *lower_dir_dentry;
-+	int bindex;
-+	int err = 0;
-+
-+	err = unionfs_partial_lookup(dentry);
-+	if (err)
-+		goto out;
-+
-+	/* trying to unlink all possible valid instances */
-+	for (bindex = dbstart(dentry); bindex <= dbend(dentry); bindex++) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+		if (!lower_dentry || !lower_dentry->d_inode)
-+			continue;
-+
-+		lower_dir_dentry = lock_parent(lower_dentry);
-+
-+		/* avoid destroying the lower inode if the object is in use */
-+		dget(lower_dentry);
-+		err = is_robranch_super(dentry->d_sb, bindex);
-+		if (!err) {
-+			/* see Documentation/filesystems/unionfs/issues.txt */
-+			lockdep_off();
-+			if (!S_ISDIR(lower_dentry->d_inode->i_mode))
-+				err = vfs_unlink(lower_dir_dentry->d_inode,
-+								lower_dentry);
-+			else
-+				err = vfs_rmdir(lower_dir_dentry->d_inode,
-+								lower_dentry);
-+			lockdep_on();
-+		}
-+
-+		/* if lower object deletion succeeds, update inode's times */
-+		if (!err)
-+			unionfs_copy_attr_times(dentry->d_inode);
-+		dput(lower_dentry);
-+		fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-+		unlock_dir(lower_dir_dentry);
-+
-+		if (err)
-+			break;
-+	}
-+
-+	/*
-+	 * Create the whiteout in branch 0 (highest priority) only if (a)
-+	 * there was an error in any intermediate branch other than branch 0
-+	 * due to failure of vfs_unlink/vfs_rmdir or (b) a branch marked or
-+	 * mounted read-only.
-+	 */
-+	if (err) {
-+		if ((bindex == 0) ||
-+		    ((bindex == dbstart(dentry)) &&
-+		     (!IS_COPYUP_ERR(err))))
-+			goto out;
-+		else {
-+			if (!IS_COPYUP_ERR(err))
-+				pr_debug("unionfs: lower object deletion "
-+					     "failed in branch:%d\n", bindex);
-+			err = create_whiteout(dentry, sbstart(dentry->d_sb));
-+		}
-+	}
-+
-+out:
-+	if (!err)
-+		inode_dec_link_count(dentry->d_inode);
-+
-+	/* We don't want to leave negative leftover dentries for revalidate. */
-+	if (!err && (dbopaque(dentry) != -1))
-+		update_bstart(dentry);
-+
-+	return err;
-+}
-+
-+int unionfs_unlink(struct inode *dir, struct dentry *dentry)
-+{
-+	int err = 0;
-+	struct inode *inode = dentry->d_inode;
-+	int valid;
-+
-+	BUG_ON(S_ISDIR(inode->i_mode));
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT);
-+
-+	valid = __unionfs_d_revalidate_chain(dentry->d_parent, NULL, false);
-+	if (unlikely(!valid)) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+	valid = __unionfs_d_revalidate_one_locked(dentry, NULL, false);
-+	if (unlikely(!valid)) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+	unionfs_check_dentry(dentry);
-+
-+	err = unionfs_unlink_whiteout(dir, dentry);
-+	/* call d_drop so the system "forgets" about us */
-+	if (!err) {
-+		unionfs_postcopyup_release(dentry);
-+		if (inode->i_nlink == 0) /* drop lower inodes */
-+			iput_lowers_all(inode, false);
-+		d_drop(dentry);
-+		/*
-+		 * if unlink/whiteout succeeded, parent dir mtime has
-+		 * changed
-+		 */
-+		unionfs_copy_attr_times(dir);
-+	}
-+
-+out:
-+	if (!err) {
-+		unionfs_check_dentry(dentry);
-+		unionfs_check_inode(dir);
-+	}
-+	unionfs_unlock_dentry(dentry->d_parent);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+static int unionfs_rmdir_first(struct inode *dir, struct dentry *dentry,
-+			       struct unionfs_dir_state *namelist)
-+{
-+	int err;
-+	struct dentry *lower_dentry;
-+	struct dentry *lower_dir_dentry = NULL;
-+
-+	/* Here we need to remove whiteout entries. */
-+	err = delete_whiteouts(dentry, dbstart(dentry), namelist);
-+	if (err)
-+		goto out;
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+
-+	lower_dir_dentry = lock_parent(lower_dentry);
-+
-+	/* avoid destroying the lower inode if the file is in use */
-+	dget(lower_dentry);
-+	err = is_robranch(dentry);
-+	if (!err) {
-+		/* see Documentation/filesystems/unionfs/issues.txt */
-+		lockdep_off();
-+		err = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
-+		lockdep_on();
-+	}
-+	dput(lower_dentry);
-+
-+	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-+	/* propagate number of hard-links */
-+	dentry->d_inode->i_nlink = unionfs_get_nlinks(dentry->d_inode);
-+
-+out:
-+	if (lower_dir_dentry)
-+		unlock_dir(lower_dir_dentry);
-+	return err;
-+}
-+
-+int unionfs_rmdir(struct inode *dir, struct dentry *dentry)
-+{
-+	int err = 0;
-+	struct unionfs_dir_state *namelist = NULL;
-+	int dstart, dend;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+	unionfs_check_dentry(dentry);
-+
-+	/* check if this unionfs directory is empty or not */
-+	err = check_empty(dentry, &namelist);
-+	if (err)
-+		goto out;
-+
-+	err = unionfs_rmdir_first(dir, dentry, namelist);
-+	dstart = dbstart(dentry);
-+	dend = dbend(dentry);
-+	/*
-+	 * We create a whiteout for the directory if there was an error to
-+	 * rmdir the first directory entry in the union.  Otherwise, we
-+	 * create a whiteout only if there is no chance that a lower
-+	 * priority branch might also have the same named directory.  IOW,
-+	 * if there is not another same-named directory at a lower priority
-+	 * branch, then we don't need to create a whiteout for it.
-+	 */
-+	if (!err) {
-+		if (dstart < dend)
-+			err = create_whiteout(dentry, dstart);
-+	} else {
-+		int new_err;
-+
-+		if (dstart == 0)
-+			goto out;
-+
-+		/* exit if the error returned was NOT -EROFS */
-+		if (!IS_COPYUP_ERR(err))
-+			goto out;
-+
-+		new_err = create_whiteout(dentry, dstart - 1);
-+		if (new_err != -EEXIST)
-+			err = new_err;
-+	}
-+
-+out:
-+	/*
-+	 * Drop references to lower dentry/inode so storage space for them
-+	 * can be reclaimed.  Then, call d_drop so the system "forgets"
-+	 * about us.
-+	 */
-+	if (!err) {
-+		iput_lowers_all(dentry->d_inode, false);
-+		dput(unionfs_lower_dentry_idx(dentry, dstart));
-+		unionfs_set_lower_dentry_idx(dentry, dstart, NULL);
-+		d_drop(dentry);
-+		/* update our lower vfsmnts, in case a copyup took place */
-+		unionfs_postcopyup_setmnt(dentry);
-+	}
-+
-+	if (namelist)
-+		free_rdstate(namelist);
-+
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-diff --git a/fs/unionfs/whiteout.c b/fs/unionfs/whiteout.c
-new file mode 100644
-index 0000000..db7a21e
---- /dev/null
-+++ b/fs/unionfs/whiteout.c
-@@ -0,0 +1,577 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * whiteout and opaque directory helpers
-+ */
-+
-+/* What do we use for whiteouts. */
-+#define UNIONFS_WHPFX ".wh."
-+#define UNIONFS_WHLEN 4
-+/*
-+ * If a directory contains this file, then it is opaque.  We start with the
-+ * .wh. flag so that it is blocked by lookup.
-+ */
-+#define UNIONFS_DIR_OPAQUE_NAME "__dir_opaque"
-+#define UNIONFS_DIR_OPAQUE UNIONFS_WHPFX UNIONFS_DIR_OPAQUE_NAME
-+
-+/* construct whiteout filename */
-+char *alloc_whname(const char *name, int len)
-+{
-+	char *buf;
-+
-+	buf = kmalloc(len + UNIONFS_WHLEN + 1, GFP_KERNEL);
-+	if (unlikely(!buf))
-+		return ERR_PTR(-ENOMEM);
-+
-+	strcpy(buf, UNIONFS_WHPFX);
-+	strlcat(buf, name, len + UNIONFS_WHLEN + 1);
-+
-+	return buf;
-+}
-+
-+/*
-+ * XXX: this can be inline or CPP macro, but is here to keep all whiteout
-+ * code in one place.
-+ */
-+void unionfs_set_max_namelen(long *namelen)
-+{
-+	*namelen -= UNIONFS_WHLEN;
-+}
-+
-+/* check if @namep is a whiteout, update @namep and @namelenp accordingly */
-+bool is_whiteout_name(char **namep, int *namelenp)
-+{
-+	if (*namelenp > UNIONFS_WHLEN &&
-+	    !strncmp(*namep, UNIONFS_WHPFX, UNIONFS_WHLEN)) {
-+		*namep += UNIONFS_WHLEN;
-+		*namelenp -= UNIONFS_WHLEN;
-+		return true;
-+	}
-+	return false;
-+}
-+
-+/* is the filename valid == !(whiteout for a file or opaque dir marker) */
-+bool is_validname(const char *name)
-+{
-+	if (!strncmp(name, UNIONFS_WHPFX, UNIONFS_WHLEN))
-+		return false;
-+	if (!strncmp(name, UNIONFS_DIR_OPAQUE_NAME,
-+		     sizeof(UNIONFS_DIR_OPAQUE_NAME) - 1))
-+		return false;
-+	return true;
-+}
-+
-+/*
-+ * Look for a whiteout @name in @lower_parent directory.  If error, return
-+ * ERR_PTR.  Caller must dput() the returned dentry if not an error.
-+ *
-+ * XXX: some callers can reuse the whname allocated buffer to avoid repeated
-+ * free then re-malloc calls.  Need to provide a different API for those
-+ * callers.
-+ */
-+struct dentry *lookup_whiteout(const char *name, struct dentry *lower_parent)
-+{
-+	char *whname = NULL;
-+	int err = 0, namelen;
-+	struct dentry *wh_dentry = NULL;
-+
-+	namelen = strlen(name);
-+	whname = alloc_whname(name, namelen);
-+	if (unlikely(IS_ERR(whname))) {
-+		err = PTR_ERR(whname);
-+		goto out;
-+	}
-+
-+	/* check if whiteout exists in this branch: lookup .wh.foo */
-+	wh_dentry = lookup_one_len(whname, lower_parent, strlen(whname));
-+	if (IS_ERR(wh_dentry)) {
-+		err = PTR_ERR(wh_dentry);
-+		goto out;
-+	}
-+
-+	/* check if negative dentry (ENOENT) */
-+	if (!wh_dentry->d_inode)
-+		goto out;
-+
-+	/* whiteout found: check if valid type */
-+	if (!S_ISREG(wh_dentry->d_inode->i_mode)) {
-+		printk(KERN_ERR "unionfs: invalid whiteout %s entry type %d\n",
-+		       whname, wh_dentry->d_inode->i_mode);
-+		dput(wh_dentry);
-+		err = -EIO;
-+		goto out;
-+	}
-+
-+out:
-+	kfree(whname);
-+	if (err)
-+		wh_dentry = ERR_PTR(err);
-+	return wh_dentry;
-+}
-+
-+/* find and return first whiteout in parent directory, else ENOENT */
-+struct dentry *find_first_whiteout(struct dentry *dentry)
-+{
-+	int bindex, bstart, bend;
-+	struct dentry *parent, *lower_parent, *wh_dentry;
-+
-+	parent = dget_parent(dentry);
-+	unionfs_lock_dentry(parent, UNIONFS_DMUTEX_WHITEOUT);
-+	bstart = dbstart(parent);
-+	bend = dbend(parent);
-+	wh_dentry = ERR_PTR(-ENOENT);
-+
-+	for (bindex = bstart; bindex <= bend; bindex++) {
-+		lower_parent = unionfs_lower_dentry_idx(parent, bindex);
-+		if (!lower_parent)
-+			continue;
-+		wh_dentry = lookup_whiteout(dentry->d_name.name, lower_parent);
-+		if (IS_ERR(wh_dentry))
-+			continue;
-+		if (wh_dentry->d_inode)
-+			break;
-+		dput(wh_dentry);
-+		wh_dentry = ERR_PTR(-ENOENT);
-+	}
-+	unionfs_unlock_dentry(parent);
-+	dput(parent);
-+
-+	return wh_dentry;
-+}
-+
-+/*
-+ * Unlink a whiteout dentry.  Returns 0 or -errno.  Caller must hold and
-+ * release dentry reference.
-+ */
-+int unlink_whiteout(struct dentry *wh_dentry)
-+{
-+	int err;
-+	struct dentry *lower_dir_dentry;
-+
-+	/* dget and lock parent dentry */
-+	lower_dir_dentry = lock_parent_wh(wh_dentry);
-+
-+	/* see Documentation/filesystems/unionfs/issues.txt */
-+	lockdep_off();
-+	err = vfs_unlink(lower_dir_dentry->d_inode, wh_dentry);
-+	lockdep_on();
-+	unlock_dir(lower_dir_dentry);
-+
-+	/*
-+	 * Whiteouts are special files and should be deleted no matter what
-+	 * (as if they never existed), in order to allow this create
-+	 * operation to succeed.  This is especially important in sticky
-+	 * directories: a whiteout may have been created by one user, but
-+	 * the newly created file may be created by another user.
-+	 * Therefore, in order to maintain Unix semantics, if the vfs_unlink
-+	 * above failed, then we have to try to directly unlink the
-+	 * whiteout.  Note: in the ODF version of unionfs, whiteout are
-+	 * handled much more cleanly.
-+	 */
-+	if (err == -EPERM) {
-+		struct inode *inode = lower_dir_dentry->d_inode;
-+		err = inode->i_op->unlink(inode, wh_dentry);
-+	}
-+	if (err)
-+		printk(KERN_ERR "unionfs: could not unlink whiteout %s, "
-+		       "err = %d\n", wh_dentry->d_name.name, err);
-+
-+	return err;
-+
-+}
-+
-+/*
-+ * Helper function when creating new objects (create, symlink, mknod, etc.).
-+ * Checks to see if there's a whiteout in @lower_dentry's parent directory,
-+ * whose name is taken from @dentry.  Then tries to remove that whiteout, if
-+ * found.  If <dentry,bindex> is a branch marked readonly, return -EROFS.
-+ * If it finds both a regular file and a whiteout, return -EIO (this should
-+ * never happen).
-+ *
-+ * Return 0 if no whiteout was found.  Return 1 if one was found and
-+ * successfully removed.  Therefore a value >= 0 tells the caller that
-+ * @lower_dentry belongs to a good branch to create the new object in).
-+ * Return -ERRNO if an error occurred during whiteout lookup or in trying to
-+ * unlink the whiteout.
-+ */
-+int check_unlink_whiteout(struct dentry *dentry, struct dentry *lower_dentry,
-+			  int bindex)
-+{
-+	int err;
-+	struct dentry *wh_dentry = NULL;
-+	struct dentry *lower_dir_dentry = NULL;
-+
-+	/* look for whiteout dentry first */
-+	lower_dir_dentry = dget_parent(lower_dentry);
-+	wh_dentry = lookup_whiteout(dentry->d_name.name, lower_dir_dentry);
-+	dput(lower_dir_dentry);
-+	if (IS_ERR(wh_dentry)) {
-+		err = PTR_ERR(wh_dentry);
-+		goto out;
-+	}
-+
-+	if (!wh_dentry->d_inode) { /* no whiteout exists*/
-+		err = 0;
-+		goto out_dput;
-+	}
-+
-+	/* check if regular file and whiteout were both found */
-+	if (unlikely(lower_dentry->d_inode)) {
-+		err = -EIO;
-+		printk(KERN_ERR "unionfs: found both whiteout and regular "
-+		       "file in directory %s (branch %d)\n",
-+		       lower_dentry->d_parent->d_name.name, bindex);
-+		goto out_dput;
-+	}
-+
-+	/* check if branch is writeable */
-+	err = is_robranch_super(dentry->d_sb, bindex);
-+	if (err)
-+		goto out_dput;
-+
-+	/* .wh.foo has been found, so let's unlink it */
-+	err = unlink_whiteout(wh_dentry);
-+	if (!err)
-+		err = 1; /* a whiteout was found and successfully removed */
-+out_dput:
-+	dput(wh_dentry);
-+out:
-+	return err;
-+}
-+
-+/*
-+ * Pass an unionfs dentry and an index.  It will try to create a whiteout
-+ * for the filename in dentry, and will try in branch 'index'.  On error,
-+ * it will proceed to a branch to the left.
-+ */
-+int create_whiteout(struct dentry *dentry, int start)
-+{
-+	int bstart, bend, bindex;
-+	struct dentry *lower_dir_dentry;
-+	struct dentry *lower_dentry;
-+	struct dentry *lower_wh_dentry;
-+	struct nameidata nd;
-+	char *name = NULL;
-+	int err = -EINVAL;
-+
-+	verify_locked(dentry);
-+
-+	bstart = dbstart(dentry);
-+	bend = dbend(dentry);
-+
-+	/* create dentry's whiteout equivalent */
-+	name = alloc_whname(dentry->d_name.name, dentry->d_name.len);
-+	if (unlikely(IS_ERR(name))) {
-+		err = PTR_ERR(name);
-+		goto out;
-+	}
-+
-+	for (bindex = start; bindex >= 0; bindex--) {
-+		lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+
-+		if (!lower_dentry) {
-+			/*
-+			 * if lower dentry is not present, create the
-+			 * entire lower dentry directory structure and go
-+			 * ahead.  Since we want to just create whiteout, we
-+			 * only want the parent dentry, and hence get rid of
-+			 * this dentry.
-+			 */
-+			lower_dentry = create_parents(dentry->d_inode,
-+						      dentry,
-+						      dentry->d_name.name,
-+						      bindex);
-+			if (!lower_dentry || IS_ERR(lower_dentry)) {
-+				int ret = PTR_ERR(lower_dentry);
-+				if (!IS_COPYUP_ERR(ret))
-+					printk(KERN_ERR
-+					       "unionfs: create_parents for "
-+					       "whiteout failed: bindex=%d "
-+					       "err=%d\n", bindex, ret);
-+				continue;
-+			}
-+		}
-+
-+		lower_wh_dentry =
-+			lookup_one_len(name, lower_dentry->d_parent,
-+				       dentry->d_name.len + UNIONFS_WHLEN);
-+		if (IS_ERR(lower_wh_dentry))
-+			continue;
-+
-+		/*
-+		 * The whiteout already exists. This used to be impossible,
-+		 * but now is possible because of opaqueness.
-+		 */
-+		if (lower_wh_dentry->d_inode) {
-+			dput(lower_wh_dentry);
-+			err = 0;
-+			goto out;
-+		}
-+
-+		err = init_lower_nd(&nd, LOOKUP_CREATE);
-+		if (unlikely(err < 0))
-+			goto out;
-+		lower_dir_dentry = lock_parent_wh(lower_wh_dentry);
-+		err = is_robranch_super(dentry->d_sb, bindex);
-+		if (!err)
-+			err = vfs_create(lower_dir_dentry->d_inode,
-+					 lower_wh_dentry,
-+					 ~current->fs->umask & S_IRUGO,
-+					 &nd);
-+		unlock_dir(lower_dir_dentry);
-+		dput(lower_wh_dentry);
-+		release_lower_nd(&nd, err);
-+
-+		if (!err || !IS_COPYUP_ERR(err))
-+			break;
-+	}
-+
-+	/* set dbopaque so that lookup will not proceed after this branch */
-+	if (!err)
-+		dbopaque(dentry) = bindex;
-+
-+out:
-+	kfree(name);
-+	return err;
-+}
-+
-+/*
-+ * Delete all of the whiteouts in a given directory for rmdir.
-+ *
-+ * lower directory inode should be locked
-+ */
-+static int do_delete_whiteouts(struct dentry *dentry, int bindex,
-+			       struct unionfs_dir_state *namelist)
-+{
-+	int err = 0;
-+	struct dentry *lower_dir_dentry = NULL;
-+	struct dentry *lower_dentry;
-+	char *name = NULL, *p;
-+	struct inode *lower_dir;
-+	int i;
-+	struct list_head *pos;
-+	struct filldir_node *cursor;
-+
-+	/* Find out lower parent dentry */
-+	lower_dir_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+	BUG_ON(!S_ISDIR(lower_dir_dentry->d_inode->i_mode));
-+	lower_dir = lower_dir_dentry->d_inode;
-+	BUG_ON(!S_ISDIR(lower_dir->i_mode));
-+
-+	err = -ENOMEM;
-+	name = __getname();
-+	if (unlikely(!name))
-+		goto out;
-+	strcpy(name, UNIONFS_WHPFX);
-+	p = name + UNIONFS_WHLEN;
-+
-+	err = 0;
-+	for (i = 0; !err && i < namelist->size; i++) {
-+		list_for_each(pos, &namelist->list[i]) {
-+			cursor =
-+				list_entry(pos, struct filldir_node,
-+					   file_list);
-+			/* Only operate on whiteouts in this branch. */
-+			if (cursor->bindex != bindex)
-+				continue;
-+			if (!cursor->whiteout)
-+				continue;
-+
-+			strlcpy(p, cursor->name, PATH_MAX - UNIONFS_WHLEN);
-+			lower_dentry =
-+				lookup_one_len(name, lower_dir_dentry,
-+					       cursor->namelen +
-+					       UNIONFS_WHLEN);
-+			if (IS_ERR(lower_dentry)) {
-+				err = PTR_ERR(lower_dentry);
-+				break;
-+			}
-+			if (lower_dentry->d_inode)
-+				err = vfs_unlink(lower_dir, lower_dentry);
-+			dput(lower_dentry);
-+			if (err)
-+				break;
-+		}
-+	}
-+
-+	__putname(name);
-+
-+	/* After all of the removals, we should copy the attributes once. */
-+	fsstack_copy_attr_times(dentry->d_inode, lower_dir_dentry->d_inode);
-+
-+out:
-+	return err;
-+}
-+
-+
-+void __delete_whiteouts(struct work_struct *work)
-+{
-+	struct sioq_args *args = container_of(work, struct sioq_args, work);
-+	struct deletewh_args *d = &args->deletewh;
-+
-+	args->err = do_delete_whiteouts(d->dentry, d->bindex, d->namelist);
-+	complete(&args->comp);
-+}
-+
-+/* delete whiteouts in a dir (for rmdir operation) using sioq if necessary */
-+int delete_whiteouts(struct dentry *dentry, int bindex,
-+		     struct unionfs_dir_state *namelist)
-+{
-+	int err;
-+	struct super_block *sb;
-+	struct dentry *lower_dir_dentry;
-+	struct inode *lower_dir;
-+	struct sioq_args args;
-+
-+	sb = dentry->d_sb;
-+
-+	BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));
-+	BUG_ON(bindex < dbstart(dentry));
-+	BUG_ON(bindex > dbend(dentry));
-+	err = is_robranch_super(sb, bindex);
-+	if (err)
-+		goto out;
-+
-+	lower_dir_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+	BUG_ON(!S_ISDIR(lower_dir_dentry->d_inode->i_mode));
-+	lower_dir = lower_dir_dentry->d_inode;
-+	BUG_ON(!S_ISDIR(lower_dir->i_mode));
-+
-+	if (!inode_permission(lower_dir, MAY_WRITE | MAY_EXEC)) {
-+		err = do_delete_whiteouts(dentry, bindex, namelist);
-+	} else {
-+		args.deletewh.namelist = namelist;
-+		args.deletewh.dentry = dentry;
-+		args.deletewh.bindex = bindex;
-+		run_sioq(__delete_whiteouts, &args);
-+		err = args.err;
-+	}
-+
-+out:
-+	return err;
-+}
-+
-+/****************************************************************************
-+ * Opaque directory helpers                                                 *
-+ ****************************************************************************/
-+
-+/*
-+ * is_opaque_dir: returns 0 if it is NOT an opaque dir, 1 if it is, and
-+ * -errno if an error occurred trying to figure this out.
-+ */
-+int is_opaque_dir(struct dentry *dentry, int bindex)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry;
-+	struct dentry *wh_lower_dentry;
-+	struct inode *lower_inode;
-+	struct sioq_args args;
-+
-+	lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+	lower_inode = lower_dentry->d_inode;
-+
-+	BUG_ON(!S_ISDIR(lower_inode->i_mode));
-+
-+	mutex_lock(&lower_inode->i_mutex);
-+
-+	if (!inode_permission(lower_inode, MAY_EXEC)) {
-+		wh_lower_dentry =
-+			lookup_one_len(UNIONFS_DIR_OPAQUE, lower_dentry,
-+				       sizeof(UNIONFS_DIR_OPAQUE) - 1);
-+	} else {
-+		args.is_opaque.dentry = lower_dentry;
-+		run_sioq(__is_opaque_dir, &args);
-+		wh_lower_dentry = args.ret;
-+	}
-+
-+	mutex_unlock(&lower_inode->i_mutex);
-+
-+	if (IS_ERR(wh_lower_dentry)) {
-+		err = PTR_ERR(wh_lower_dentry);
-+		goto out;
-+	}
-+
-+	/* This is an opaque dir iff wh_lower_dentry is positive */
-+	err = !!wh_lower_dentry->d_inode;
-+
-+	dput(wh_lower_dentry);
-+out:
-+	return err;
-+}
-+
-+void __is_opaque_dir(struct work_struct *work)
-+{
-+	struct sioq_args *args = container_of(work, struct sioq_args, work);
-+
-+	args->ret = lookup_one_len(UNIONFS_DIR_OPAQUE, args->is_opaque.dentry,
-+				   sizeof(UNIONFS_DIR_OPAQUE) - 1);
-+	complete(&args->comp);
-+}
-+
-+int make_dir_opaque(struct dentry *dentry, int bindex)
-+{
-+	int err = 0;
-+	struct dentry *lower_dentry, *diropq;
-+	struct inode *lower_dir;
-+	struct nameidata nd;
-+	kernel_cap_t orig_cap;
-+
-+	/*
-+	 * Opaque directory whiteout markers are special files (like regular
-+	 * whiteouts), and should appear to the users as if they don't
-+	 * exist.  They should be created/deleted regardless of directory
-+	 * search/create permissions, but only for the duration of this
-+	 * creation of the .wh.__dir_opaque: file.  Note, this does not
-+	 * circumvent normal ->permission).
-+	 */
-+	orig_cap = current->cap_effective;
-+	cap_raise(current->cap_effective, CAP_DAC_READ_SEARCH);
-+	cap_raise(current->cap_effective, CAP_DAC_OVERRIDE);
-+
-+	lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+	lower_dir = lower_dentry->d_inode;
-+	BUG_ON(!S_ISDIR(dentry->d_inode->i_mode) ||
-+	       !S_ISDIR(lower_dir->i_mode));
-+
-+	mutex_lock(&lower_dir->i_mutex);
-+	diropq = lookup_one_len(UNIONFS_DIR_OPAQUE, lower_dentry,
-+				sizeof(UNIONFS_DIR_OPAQUE) - 1);
-+	if (IS_ERR(diropq)) {
-+		err = PTR_ERR(diropq);
-+		goto out;
-+	}
-+
-+	err = init_lower_nd(&nd, LOOKUP_CREATE);
-+	if (unlikely(err < 0))
-+		goto out;
-+	if (!diropq->d_inode)
-+		err = vfs_create(lower_dir, diropq, S_IRUGO, &nd);
-+	if (!err)
-+		dbopaque(dentry) = bindex;
-+	release_lower_nd(&nd, err);
-+
-+	dput(diropq);
-+
-+out:
-+	mutex_unlock(&lower_dir->i_mutex);
-+	current->cap_effective = orig_cap;
-+	return err;
-+}
-diff --git a/fs/unionfs/xattr.c b/fs/unionfs/xattr.c
-new file mode 100644
-index 0000000..93a8fce
---- /dev/null
-+++ b/fs/unionfs/xattr.c
-@@ -0,0 +1,153 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005      Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003      Puja Gupta
-+ * Copyright (c) 2003      Harikesavan Krishnan
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/* This is lifted from fs/xattr.c */
-+void *unionfs_xattr_alloc(size_t size, size_t limit)
-+{
-+	void *ptr;
-+
-+	if (size > limit)
-+		return ERR_PTR(-E2BIG);
-+
-+	if (!size)		/* size request, no buffer is needed */
-+		return NULL;
-+
-+	ptr = kmalloc(size, GFP_KERNEL);
-+	if (unlikely(!ptr))
-+		return ERR_PTR(-ENOMEM);
-+	return ptr;
-+}
-+
-+/*
-+ * BKL held by caller.
-+ * dentry->d_inode->i_mutex locked
-+ */
-+ssize_t unionfs_getxattr(struct dentry *dentry, const char *name, void *value,
-+			 size_t size)
-+{
-+	struct dentry *lower_dentry = NULL;
-+	int err = -EOPNOTSUPP;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+
-+	err = vfs_getxattr(lower_dentry, (char *) name, value, size);
-+
-+out:
-+	unionfs_check_dentry(dentry);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+/*
-+ * BKL held by caller.
-+ * dentry->d_inode->i_mutex locked
-+ */
-+int unionfs_setxattr(struct dentry *dentry, const char *name,
-+		     const void *value, size_t size, int flags)
-+{
-+	struct dentry *lower_dentry = NULL;
-+	int err = -EOPNOTSUPP;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+
-+	err = vfs_setxattr(lower_dentry, (char *) name, (void *) value,
-+			   size, flags);
-+
-+out:
-+	unionfs_check_dentry(dentry);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+/*
-+ * BKL held by caller.
-+ * dentry->d_inode->i_mutex locked
-+ */
-+int unionfs_removexattr(struct dentry *dentry, const char *name)
-+{
-+	struct dentry *lower_dentry = NULL;
-+	int err = -EOPNOTSUPP;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+
-+	err = vfs_removexattr(lower_dentry, (char *) name);
-+
-+out:
-+	unionfs_check_dentry(dentry);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-+
-+/*
-+ * BKL held by caller.
-+ * dentry->d_inode->i_mutex locked
-+ */
-+ssize_t unionfs_listxattr(struct dentry *dentry, char *list, size_t size)
-+{
-+	struct dentry *lower_dentry = NULL;
-+	int err = -EOPNOTSUPP;
-+	char *encoded_list = NULL;
-+
-+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+	if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
-+		err = -ESTALE;
-+		goto out;
-+	}
-+
-+	lower_dentry = unionfs_lower_dentry(dentry);
-+
-+	encoded_list = list;
-+	err = vfs_listxattr(lower_dentry, encoded_list, size);
-+
-+out:
-+	unionfs_check_dentry(dentry);
-+	unionfs_unlock_dentry(dentry);
-+	unionfs_read_unlock(dentry->d_sb);
-+	return err;
-+}
-diff --git a/include/linux/fs_stack.h b/include/linux/fs_stack.h
-index bb516ce..6615a52 100644
---- a/include/linux/fs_stack.h
-+++ b/include/linux/fs_stack.h
-@@ -1,17 +1,27 @@
-+/*
-+ * Copyright (c) 2006-2007 Erez Zadok
-+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2006-2007 Stony Brook University
-+ * Copyright (c) 2006-2007 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
- #ifndef _LINUX_FS_STACK_H
- #define _LINUX_FS_STACK_H
- 
--/* This file defines generic functions used primarily by stackable
-+/*
-+ * This file defines generic functions used primarily by stackable
-  * filesystems; none of these functions require i_mutex to be held.
-  */
- 
- #include <linux/fs.h>
- 
- /* externs for fs/stack.c */
--extern void fsstack_copy_attr_all(struct inode *dest, const struct inode *src,
--				int (*get_nlinks)(struct inode *));
--
--extern void fsstack_copy_inode_size(struct inode *dst, const struct inode *src);
-+extern void fsstack_copy_attr_all(struct inode *dest, const struct inode *src);
-+extern void fsstack_copy_inode_size(struct inode *dst, struct inode *src);
- 
- /* inlines */
- static inline void fsstack_copy_attr_atime(struct inode *dest,
-diff --git a/include/linux/magic.h b/include/linux/magic.h
-index 1fa0c2c..67043ed 100644
---- a/include/linux/magic.h
-+++ b/include/linux/magic.h
-@@ -35,6 +35,8 @@
- #define REISER2FS_SUPER_MAGIC_STRING	"ReIsEr2Fs"
- #define REISER2FS_JR_SUPER_MAGIC_STRING	"ReIsEr3Fs"
- 
-+#define UNIONFS_SUPER_MAGIC 0xf15f083d
-+
- #define SMB_SUPER_MAGIC		0x517B
- #define USBDEVICE_SUPER_MAGIC	0x9fa2
- #define CGROUP_SUPER_MAGIC	0x27e0eb
-diff --git a/include/linux/splice.h b/include/linux/splice.h
-index 528dcb9..4b5727c 100644
---- a/include/linux/splice.h
-+++ b/include/linux/splice.h
-@@ -70,5 +70,10 @@ extern ssize_t splice_to_pipe(struct pipe_inode_info *,
- 			      struct splice_pipe_desc *);
- extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
- 				      splice_direct_actor *);
-+extern long vfs_splice_from(struct pipe_inode_info *pipe, struct file *out,
-+			    loff_t *ppos, size_t len, unsigned int flags);
-+extern long vfs_splice_to(struct file *in, loff_t *ppos,
-+			  struct pipe_inode_info *pipe, size_t len,
-+			  unsigned int flags);
- 
- #endif
-diff --git a/include/linux/union_fs.h b/include/linux/union_fs.h
-new file mode 100644
-index 0000000..bc15a16
---- /dev/null
-+++ b/include/linux/union_fs.h
-@@ -0,0 +1,22 @@
-+/*
-+ * Copyright (c) 2003-2008 Erez Zadok
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2003-2008 Stony Brook University
-+ * Copyright (c) 2003-2008 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#ifndef _LINUX_UNION_FS_H
-+#define _LINUX_UNION_FS_H
-+
-+/*
-+ * DEFINITIONS FOR USER AND KERNEL CODE:
-+ */
-+# define UNIONFS_IOCTL_INCGEN		_IOR(0x15, 11, int)
-+# define UNIONFS_IOCTL_QUERYFILE	_IOR(0x15, 15, int)
-+
-+#endif /* _LINUX_UNIONFS_H */
-+