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diff --git a/main/linux-scst/unionfs-2.5.7_for_2.6.36.diff b/main/linux-scst/unionfs-2.5.7_for_2.6.36.diff
new file mode 100644
index 0000000000..fabe758098
--- /dev/null
+++ b/main/linux-scst/unionfs-2.5.7_for_2.6.36.diff
@@ -0,0 +1,11253 @@
+diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
+index 4303614..5ade4a8 100644
+--- a/Documentation/filesystems/00-INDEX
++++ b/Documentation/filesystems/00-INDEX
+@@ -112,6 +112,8 @@ 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 f2a2b8e..11d7f45 100644
+--- a/MAINTAINERS
++++ b/MAINTAINERS
+@@ -5917,6 +5917,14 @@ F: Documentation/cdrom/
+ F: drivers/cdrom/cdrom.c
+ F: include/linux/cdrom.h
+
++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
++
+ UNSORTED BLOCK IMAGES (UBI)
+ M: Artem Bityutskiy <dedekind1@gmail.com>
+ W: http://www.linux-mtd.infradead.org/
+diff --git a/fs/Kconfig b/fs/Kconfig
+index 3d18530..65b6aa1 100644
+--- a/fs/Kconfig
++++ b/fs/Kconfig
+@@ -169,6 +169,7 @@ if MISC_FILESYSTEMS
+ source "fs/adfs/Kconfig"
+ source "fs/affs/Kconfig"
+ source "fs/ecryptfs/Kconfig"
++source "fs/unionfs/Kconfig"
+ source "fs/hfs/Kconfig"
+ source "fs/hfsplus/Kconfig"
+ source "fs/befs/Kconfig"
+diff --git a/fs/Makefile b/fs/Makefile
+index e6ec1d3..787332e 100644
+--- a/fs/Makefile
++++ b/fs/Makefile
+@@ -84,6 +84,7 @@ 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/namei.c b/fs/namei.c
+index 24896e8..db22420 100644
+--- a/fs/namei.c
++++ b/fs/namei.c
+@@ -385,6 +385,7 @@ 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 8f1dfae..7a57fab 100644
+--- a/fs/splice.c
++++ b/fs/splice.c
+@@ -1092,8 +1092,8 @@ 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)
+ {
+ ssize_t (*splice_write)(struct pipe_inode_info *, struct file *,
+ loff_t *, size_t, unsigned int);
+@@ -1116,13 +1116,14 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
+
+ return 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)
+ {
+ ssize_t (*splice_read)(struct file *, loff_t *,
+ struct pipe_inode_info *, size_t, unsigned int);
+@@ -1142,6 +1143,7 @@ static long do_splice_to(struct file *in, loff_t *ppos,
+
+ return splice_read(in, ppos, pipe, len, flags);
+ }
++EXPORT_SYMBOL_GPL(vfs_splice_to);
+
+ /**
+ * splice_direct_to_actor - splices data directly between two non-pipes
+@@ -1211,7 +1213,7 @@ 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;
+
+@@ -1270,8 +1272,8 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
+ {
+ struct file *file = sd->u.file;
+
+- return do_splice_from(pipe, file, &file->f_pos, sd->total_len,
+- sd->flags);
++ return vfs_splice_from(pipe, file, &file->f_pos, sd->total_len,
++ sd->flags);
+ }
+
+ /**
+@@ -1368,7 +1370,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
+ } else
+ off = &out->f_pos;
+
+- ret = do_splice_from(ipipe, out, off, len, flags);
++ ret = vfs_splice_from(ipipe, out, off, len, flags);
+
+ if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
+ ret = -EFAULT;
+@@ -1388,7 +1390,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
+ } else
+ off = &in->f_pos;
+
+- ret = do_splice_to(in, off, opipe, len, flags);
++ ret = vfs_splice_to(in, off, opipe, 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 4a6f7f4..7eeef12 100644
+--- a/fs/stack.c
++++ b/fs/stack.c
+@@ -1,8 +1,20 @@
++/*
++ * Copyright (c) 2006-2009 Erez Zadok
++ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
++ * Copyright (c) 2006-2009 Stony Brook University
++ * Copyright (c) 2006-2009 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
+diff --git a/fs/unionfs/Kconfig b/fs/unionfs/Kconfig
+new file mode 100644
+index 0000000..f3c1ac4
+--- /dev/null
++++ b/fs/unionfs/Kconfig
+@@ -0,0 +1,24 @@
++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.
+diff --git a/fs/unionfs/Makefile b/fs/unionfs/Makefile
+new file mode 100644
+index 0000000..86c32ba
+--- /dev/null
++++ b/fs/unionfs/Makefile
+@@ -0,0 +1,17 @@
++UNIONFS_VERSION="2.5.7 (for 2.6.36)"
++
++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..51ea65e
+--- /dev/null
++++ b/fs/unionfs/commonfops.c
+@@ -0,0 +1,896 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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,
++ struct dentry *parent, 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_lck_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(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, current_cred());
++ if (IS_ERR(lower_file)) {
++ branchput(sb, bindex);
++ 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 dentry *parent = dget_parent(dentry);
++ struct inode *parent_inode = 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, current_cred());
++ 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:
++ dput(parent);
++ return err;
++}
++
++/* perform a delayed copyup of a read-write file on a read-only branch */
++static int do_delayed_copyup(struct file *file, struct dentry *parent)
++{
++ int bindex, bstart, bend, err = 0;
++ struct dentry *dentry = file->f_path.dentry;
++ struct inode *parent_inode = 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, parent,
++ 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 dentry *parent,
++ 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, parent);
++ /* 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);
++ }
++ return err;
++}
++
++/*
++ * Revalidate the struct file
++ * @file: file to revalidate
++ * @parent: parent dentry (locked by caller)
++ * @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, struct dentry *parent,
++ 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);
++ verify_locked(parent);
++
++ /*
++ * First revalidate the dentry inside struct file,
++ * but not unhashed dentries.
++ */
++ if (!d_deleted(dentry) &&
++ !__unionfs_d_revalidate(dentry, parent, willwrite)) {
++ err = -ESTALE;
++ goto out;
++ }
++
++ sbgen = atomic_read(&UNIONFS_SB(sb)->generation);
++ dgen = atomic_read(&UNIONFS_D(dentry)->generation);
++
++ if (unlikely(sbgen > dgen)) { /* XXX: should never happen */
++ pr_debug("unionfs: failed to revalidate dentry (%s)\n",
++ dentry->d_name.name);
++ err = -ESTALE;
++ goto out;
++ }
++
++ err = __unionfs_file_revalidate(file, dentry, parent, 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,
++ current_cred());
++ 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 *parent)
++{
++ 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(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, current_cred());
++ 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;
++ struct dentry *parent;
++ int bindex = 0, bstart = 0, bend = 0;
++ int size;
++ int valid = 0;
++
++ unionfs_read_lock(inode->i_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ /* don't open unhashed/deleted files */
++ if (d_deleted(dentry)) {
++ err = -ENOENT;
++ goto out_nofree;
++ }
++
++ /* XXX: should I change 'false' below to the 'willwrite' flag? */
++ valid = __unionfs_d_revalidate(dentry, parent, 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, parent); /* 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);
++ }
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++ int bindex, bstart, bend;
++ int fgen, err = 0;
++
++ /*
++ * Since mm/memory.c:might_fault() (under PROVE_LOCKING) was
++ * modified in 2.6.29-rc1 to call might_lock_read on mmap_sem, this
++ * has been causing false positives in file system stacking layers.
++ * In particular, our ->mmap is called after sys_mmap2 already holds
++ * mmap_sem, then we lock our own mutexes; but earlier, it's
++ * possible for lockdep to have locked our mutexes first, and then
++ * we call a lower ->readdir which could call might_fault. The
++ * different ordering of the locks is what lockdep complains about
++ * -- unnecessarily. Therefore, we have no choice but to tell
++ * lockdep to temporarily turn off lockdep here. Note: the comments
++ * inside might_sleep also suggest that it would have been
++ * nicer to only annotate paths that needs that might_lock_read.
++ */
++ lockdep_off();
++ unionfs_read_lock(sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ /*
++ * We try to revalidate, but the VFS ignores return return values
++ * from file->release, so we must always try to succeed here,
++ * including to do the kfree and dput below. So if revalidation
++ * failed, all we can do is print some message and keep going.
++ */
++ err = unionfs_file_revalidate(file, parent,
++ UNIONFS_F(file)->wrote_to_file);
++ if (!err)
++ 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);
++
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ unionfs_read_unlock(sb);
++ lockdep_on();
++ 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);
++#ifdef CONFIG_COMPAT
++ } else if (lower_file->f_op->ioctl) {
++ err = lower_file->f_op->compat_ioctl(
++ lower_file->f_path.dentry->d_inode,
++ lower_file, cmd, arg);
++#endif
++ }
++
++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, struct dentry *parent,
++ 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, parent);
++ 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;
++ struct dentry *parent;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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, parent, 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_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++ int bindex, bstart, bend;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent,
++ 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_unlock_parent(dentry, parent);
++ 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..bba3a75
+--- /dev/null
++++ b/fs/unionfs/copyup.c
+@@ -0,0 +1,896 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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)) {
++ const struct cred *old_creds;
++ struct cred *new_creds;
++
++ new_creds = prepare_creds();
++ if (unlikely(!new_creds)) {
++ err = -ENOMEM;
++ goto out;
++ }
++ cap_raise(new_creds->cap_effective, CAP_FOWNER);
++ old_creds = override_creds(new_creds);
++ err = vfs_setxattr(new_lower_dentry, name_list,
++ attr_value, size, 0);
++ revert_creds(old_creds);
++ }
++ 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, current_cred());
++ 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, current_cred());
++ 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, 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) {
++ /*
++ * if directory creation succeeded, but inode copyup failed,
++ * then purge new dentries.
++ */
++ if (dbstart(dentry) < old_bstart &&
++ ibstart(dentry->d_inode) > dbstart(dentry))
++ __clear(dentry, NULL, old_bstart, old_bend,
++ unionfs_lower_dentry(dentry), dbstart(dentry));
++ 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_lck_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_lck_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..100d2c6
+--- /dev/null
++++ b/fs/unionfs/debug.c
+@@ -0,0 +1,532 @@
++/*
++ * Copyright (c) 2003-2010 Erez Zadok
++ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
++ * Copyright (c) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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);
++ }
++ }
++}
++
++/* 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..a0c3bba
+--- /dev/null
++++ b/fs/unionfs/dentry.c
+@@ -0,0 +1,397 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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);
++ }
++}
++
++/*
++ * 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 parent is valid,
++ * otherwise return false (and let's hope the VFS will try to re-lookup this
++ * dentry). Returns true if valid, false otherwise.
++ */
++bool __unionfs_d_revalidate(struct dentry *dentry, struct dentry *parent,
++ bool willwrite)
++{
++ bool valid = true; /* default is valid */
++ struct dentry *lower_dentry;
++ struct dentry *result;
++ int bindex, bstart, bend;
++ int sbgen, dgen, pdgen;
++ int positive = 0;
++ int interpose_flag;
++
++ verify_locked(dentry);
++ verify_locked(parent);
++
++ /* if the dentry is unhashed, do NOT revalidate */
++ if (d_deleted(dentry))
++ goto out;
++
++ dgen = atomic_read(&UNIONFS_D(dentry)->generation);
++
++ if (is_newer_lower(dentry)) {
++ /* root dentry is always valid */
++ 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);
++ }
++
++ sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
++
++ BUG_ON(dbstart(dentry) == -1);
++ if (dentry->d_inode)
++ positive = 1;
++
++ /* if our dentry is valid, then validate all lower ones */
++ if (sbgen == dgen)
++ goto validate_lowers;
++
++ /* 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(parent)->generation);
++
++ /* Free the pointers for our inodes and this dentry. */
++ path_put_lowers_all(dentry, false);
++
++ 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, parent, 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))) {
++ /* call make_bad_inode here ? */
++ d_drop(dentry);
++ valid = false;
++ goto out;
++ }
++
++ /*
++ * if we got here then we have revalidated our dentry and all lower
++ * ones, so we can return safely.
++ */
++ if (!valid) /* lower dentry revalidation failed */
++ goto out;
++
++ /*
++ * If the parent's gen no. matches the superblock's gen no., then
++ * we can update our denty's gen no. If they didn't match, then it
++ * was OK to revalidate this dentry with a stale parent, but we'll
++ * purposely not update our dentry's gen no. (so it can be redone);
++ * and, we'll mark our parent dentry as invalid so it'll force it
++ * (and our dentry) to be revalidated.
++ */
++ if (pdgen == sbgen)
++ atomic_set(&UNIONFS_D(dentry)->generation, sbgen);
++ goto out;
++
++validate_lowers:
++
++ /* 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) 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:
++ 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 */
++}
++
++static int unionfs_d_revalidate(struct dentry *dentry,
++ struct nameidata *nd_unused)
++{
++ bool valid = true;
++ int err = 1; /* 1 means valid for the VFS */
++ struct dentry *parent;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (valid) {
++ unionfs_postcopyup_setmnt(dentry);
++ unionfs_check_dentry(dentry);
++ } else {
++ d_drop(dentry);
++ err = valid;
++ }
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ 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..7da0ff0
+--- /dev/null
++++ b/fs/unionfs/dirfops.c
+@@ -0,0 +1,302 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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 dentry *parent;
++ 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);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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:
++ if (!err)
++ unionfs_check_file(file);
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++ loff_t err;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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:
++ if (!err)
++ unionfs_check_file(file);
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ 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..033343b
+--- /dev/null
++++ b/fs/unionfs/dirhelper.c
+@@ -0,0 +1,158 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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 dentry *parent,
++ 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, parent);
++ 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, current_cred());
++ 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..5b77eac
+--- /dev/null
++++ b/fs/unionfs/fanout.h
+@@ -0,0 +1,407 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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 struct dentry *unionfs_lock_parent(struct dentry *d,
++ unsigned int subclass)
++{
++ struct dentry *p;
++
++ BUG_ON(!d);
++ p = dget_parent(d);
++ if (p != d)
++ mutex_lock_nested(&UNIONFS_D(p)->lock, subclass);
++ return p;
++}
++
++static inline void unionfs_unlock_parent(struct dentry *d, struct dentry *p)
++{
++ BUG_ON(!d);
++ BUG_ON(!p);
++ if (p != d) {
++ BUG_ON(!mutex_is_locked(&UNIONFS_D(p)->lock));
++ mutex_unlock(&UNIONFS_D(p)->lock);
++ }
++ dput(p);
++}
++
++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..1c694c3
+--- /dev/null
++++ b/fs/unionfs/file.c
+@@ -0,0 +1,382 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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;
++ struct dentry *parent;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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:
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ 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 dentry *parent;
++ const struct vm_operations_struct *saved_vm_ops = NULL;
++
++ /*
++ * Since mm/memory.c:might_fault() (under PROVE_LOCKING) was
++ * modified in 2.6.29-rc1 to call might_lock_read on mmap_sem, this
++ * has been causing false positives in file system stacking layers.
++ * In particular, our ->mmap is called after sys_mmap2 already holds
++ * mmap_sem, then we lock our own mutexes; but earlier, it's
++ * possible for lockdep to have locked our mutexes first, and then
++ * we call a lower ->readdir which could call might_fault. The
++ * different ordering of the locks is what lockdep complains about
++ * -- unnecessarily. Therefore, we have no choice but to tell
++ * lockdep to temporarily turn off lockdep here. Note: the comments
++ * inside might_sleep also suggest that it would have been
++ * nicer to only annotate paths that needs that might_lock_read.
++ */
++ lockdep_off();
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_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, parent, 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(parent->d_inode);
++ unionfs_check_file(file);
++ }
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ unionfs_read_unlock(dentry->d_sb);
++ lockdep_on();
++ return err;
++}
++
++int unionfs_fsync(struct file *file, int datasync)
++{
++ int bindex, bstart, bend;
++ struct file *lower_file;
++ struct dentry *dentry = file->f_path.dentry;
++ struct dentry *lower_dentry;
++ struct dentry *parent;
++ struct inode *lower_inode, *inode;
++ int err = -EINVAL;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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, 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_unlock_parent(dentry, parent);
++ 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 dentry *parent;
++ struct inode *lower_inode, *inode;
++ int err = 0;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ err = unionfs_file_revalidate(file, parent, 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_unlock_parent(dentry, parent);
++ 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,
++#ifdef CONFIG_COMPAT
++ .compat_ioctl = unionfs_ioctl,
++#endif
++ .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..4c36f16
+--- /dev/null
++++ b/fs/unionfs/inode.c
+@@ -0,0 +1,1061 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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 *dir, struct dentry *dentry,
++ int mode, struct nameidata *nd_unused)
++{
++ int err = 0;
++ struct dentry *lower_dentry = NULL;
++ struct dentry *lower_parent_dentry = NULL;
++ struct dentry *parent;
++ int valid = 0;
++ struct nameidata lower_nd;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ err = -ESTALE; /* same as what real_lookup does */
++ goto out;
++ }
++
++ lower_dentry = find_writeable_branch(dir, 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_unlock;
++ }
++
++ err = init_lower_nd(&lower_nd, LOOKUP_CREATE);
++ if (unlikely(err < 0))
++ goto out_unlock;
++ 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, dir->i_sb, 0));
++ if (!err) {
++ unionfs_copy_attr_times(dir);
++ fsstack_copy_inode_size(dir,
++ lower_parent_dentry->d_inode);
++ /* update no. of links on parent directory */
++ dir->i_nlink = unionfs_get_nlinks(dir);
++ }
++ }
++
++out_unlock:
++ unlock_dir(lower_parent_dentry);
++out:
++ if (!err) {
++ unionfs_postcopyup_setmnt(dentry);
++ unionfs_check_inode(dir);
++ unionfs_check_dentry(dentry);
++ }
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ 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 *dir,
++ struct dentry *dentry,
++ struct nameidata *nd_unused)
++{
++ struct dentry *ret, *parent;
++ int err = 0;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++
++ /*
++ * As long as we lock/dget the parent, then can skip validating the
++ * parent now; we may have to rebuild this dentry on the next
++ * ->d_revalidate, however.
++ */
++
++ /* 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, parent, INTERPOSE_LOOKUP);
++
++ 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);
++ }
++
++ unionfs_check_inode(dir);
++ if (!IS_ERR(ret))
++ unionfs_check_dentry(dentry);
++ unionfs_check_dentry(parent);
++ unionfs_unlock_dentry(dentry); /* locked in new_dentry_private data */
++
++out:
++ unionfs_unlock_parent(dentry, 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;
++ struct dentry *old_parent, *new_parent;
++ char *name = NULL;
++ bool valid;
++
++ unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ old_parent = dget_parent(old_dentry);
++ new_parent = dget_parent(new_dentry);
++ unionfs_double_lock_parents(old_parent, new_parent);
++ unionfs_double_lock_dentry(old_dentry, new_dentry);
++
++ valid = __unionfs_d_revalidate(old_dentry, old_parent, false);
++ if (unlikely(!valid)) {
++ err = -ESTALE;
++ goto out;
++ }
++ if (new_dentry->d_inode) {
++ valid = __unionfs_d_revalidate(new_dentry, new_parent, false);
++ if (unlikely(!valid)) {
++ 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_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_double_unlock_dentry(old_dentry, new_dentry);
++ unionfs_double_unlock_parents(old_parent, new_parent);
++ dput(new_parent);
++ dput(old_parent);
++ unionfs_read_unlock(old_dentry->d_sb);
++
++ return err;
++}
++
++static int unionfs_symlink(struct inode *dir, 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;
++ struct dentry *parent;
++ char *name = NULL;
++ int valid = 0;
++ umode_t mode;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ 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(dir, 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_unlock;
++ }
++
++ mode = S_IALLUGO;
++ err = vfs_symlink(lower_parent_dentry->d_inode, lower_dentry, symname);
++ if (!err) {
++ err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
++ if (!err) {
++ unionfs_copy_attr_times(dir);
++ fsstack_copy_inode_size(dir,
++ lower_parent_dentry->d_inode);
++ /* update no. of links on parent directory */
++ dir->i_nlink = unionfs_get_nlinks(dir);
++ }
++ }
++
++out_unlock:
++ unlock_dir(lower_parent_dentry);
++out:
++ dput(wh_dentry);
++ kfree(name);
++
++ if (!err) {
++ unionfs_postcopyup_setmnt(dentry);
++ unionfs_check_inode(dir);
++ unionfs_check_dentry(dentry);
++ }
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ unionfs_read_unlock(dentry->d_sb);
++ return err;
++}
++
++static int unionfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
++{
++ int err = 0;
++ struct dentry *lower_dentry = NULL;
++ struct dentry *lower_parent_dentry = NULL;
++ struct dentry *parent;
++ int bindex = 0, bstart;
++ char *name = NULL;
++ int valid;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ err = -ESTALE; /* same as what real_lookup does */
++ 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(dir, 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++) {
++ /* XXX: use path_put_lowers? */
++ 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, dir->i_sb, 0));
++ if (!err) {
++ unionfs_copy_attr_times(dir);
++ fsstack_copy_inode_size(dir,
++ lower_parent_dentry->d_inode);
++
++ /* update number of links on parent directory */
++ dir->i_nlink = unionfs_get_nlinks(dir);
++ }
++
++ 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(dir);
++ unionfs_check_dentry(dentry);
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ unionfs_read_unlock(dentry->d_sb);
++
++ return err;
++}
++
++static int unionfs_mknod(struct inode *dir, 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;
++ struct dentry *parent;
++ char *name = NULL;
++ int valid = 0;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ 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(dir, 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_unlock;
++ }
++
++ err = vfs_mknod(lower_parent_dentry->d_inode, lower_dentry, mode, dev);
++ if (!err) {
++ err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
++ if (!err) {
++ unionfs_copy_attr_times(dir);
++ fsstack_copy_inode_size(dir,
++ lower_parent_dentry->d_inode);
++ /* update no. of links on parent directory */
++ dir->i_nlink = unionfs_get_nlinks(dir);
++ }
++ }
++
++out_unlock:
++ unlock_dir(lower_parent_dentry);
++out:
++ dput(wh_dentry);
++ kfree(name);
++
++ if (!err) {
++ unionfs_postcopyup_setmnt(dentry);
++ unionfs_check_inode(dir);
++ unionfs_check_dentry(dentry);
++ }
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ unionfs_read_unlock(dentry->d_sb);
++ return err;
++}
++
++/* requires sb, dentry, and parent to already be locked */
++static int __unionfs_readlink(struct dentry *dentry, char __user *buf,
++ int bufsiz)
++{
++ int err;
++ struct dentry *lower_dentry;
++
++ 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:
++ return err;
++}
++
++static int unionfs_readlink(struct dentry *dentry, char __user *buf,
++ int bufsiz)
++{
++ int err;
++ struct dentry *parent;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ if (unlikely(!__unionfs_d_revalidate(dentry, parent, false))) {
++ err = -ESTALE;
++ goto out;
++ }
++
++ err = __unionfs_readlink(dentry, buf, bufsiz);
++
++out:
++ unionfs_check_dentry(dentry);
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ unionfs_read_unlock(dentry->d_sb);
++
++ return err;
++}
++
++static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd)
++{
++ char *buf;
++ int len = PAGE_SIZE, err;
++ mm_segment_t old_fs;
++ struct dentry *parent;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ /* 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 = __unionfs_readlink(dentry, 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 >= 0) {
++ unionfs_check_nd(nd);
++ unionfs_check_dentry(dentry);
++ }
++
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ unionfs_read_unlock(dentry->d_sb);
++
++ return ERR_PTR(err);
++}
++
++/* this @nd *IS* still used */
++static void unionfs_put_link(struct dentry *dentry, struct nameidata *nd,
++ void *cookie)
++{
++ struct dentry *parent;
++ char *buf;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ if (unlikely(!__unionfs_d_revalidate(dentry, parent, false)))
++ printk(KERN_ERR
++ "unionfs: put_link failed to revalidate dentry\n");
++
++ unionfs_check_dentry(dentry);
++#if 0
++ /* XXX: can't run this check b/c this fxn can receive a poisoned 'nd' PTR */
++ unionfs_check_nd(nd);
++#endif
++ buf = nd_get_link(nd);
++ if (!IS_ERR(buf))
++ kfree(buf);
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ unionfs_read_unlock(dentry->d_sb);
++}
++
++/*
++ * This is a variant of fs/namei.c:permission() or inode_permission() which
++ * skips over EROFS tests (because we perform copyup on EROFS).
++ */
++static int __inode_permission(struct inode *inode, int mask)
++{
++ int retval;
++
++ /* nobody gets write access to an immutable file */
++ if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode))
++ return -EACCES;
++
++ /* Ordinary permission routines do not understand MAY_APPEND. */
++ if (inode->i_op && inode->i_op->permission) {
++ retval = inode->i_op->permission(inode, mask);
++ if (!retval) {
++ /*
++ * Exec permission on a regular file is denied if none
++ * of the execute bits are set.
++ *
++ * This check should be done by the ->permission()
++ * method.
++ */
++ if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode) &&
++ !(inode->i_mode & S_IXUGO))
++ return -EACCES;
++ }
++ } else {
++ retval = generic_permission(inode, mask, NULL);
++ }
++ if (retval)
++ return retval;
++
++ return security_inode_permission(inode,
++ mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND));
++}
++
++/*
++ * 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);
++ struct inode *inode_grabbed = igrab(inode);
++ struct dentry *dentry = d_find_alias(inode);
++
++ if (dentry)
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ 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. However, if user never had
++ * access to the file, then no copyup could ever take place.
++ */
++ err = __inode_permission(lower_inode, mask);
++ if (err && err != -EACCES && err != EPERM && bindex > 0) {
++ umode_t mode = lower_inode->i_mode;
++ if ((is_robranch_super(inode->i_sb, bindex) ||
++ __is_rdonly(lower_inode)) &&
++ (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
++ err = 0;
++ if (IS_COPYUP_ERR(err))
++ err = 0;
++ }
++
++ /*
++ * NFS HACK: NFSv2/3 return EACCES on readonly-exported,
++ * locally readonly-mounted file systems, instead of EROFS
++ * like other file systems do. So we have no choice here
++ * but to intercept this and ignore it for NFS branches
++ * marked readonly. Specifically, we avoid using NFS's own
++ * "broken" ->permission method, and rely on
++ * generic_permission() to do basic checking for us.
++ */
++ if (err && err == -EACCES &&
++ is_robranch_super(inode->i_sb, bindex) &&
++ lower_inode->i_sb->s_magic == NFS_SUPER_MAGIC)
++ err = generic_permission(lower_inode, mask, NULL);
++
++ /*
++ * 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);
++ if (dentry) {
++ unionfs_unlock_dentry(dentry);
++ dput(dentry);
++ }
++ iput(inode_grabbed);
++ return err;
++}
++
++static int unionfs_setattr(struct dentry *dentry, struct iattr *ia)
++{
++ int err = 0;
++ struct dentry *lower_dentry;
++ struct dentry *parent;
++ struct inode *inode;
++ struct inode *lower_inode;
++ int bstart, bend, bindex;
++ loff_t size;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ if (unlikely(!__unionfs_d_revalidate(dentry, parent, 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);
++ if (!lower_dentry) { /* should never happen after above revalidate */
++ err = -EINVAL;
++ goto out;
++ }
++ lower_inode = unionfs_lower_inode(inode);
++
++ /* check if user has permission to change lower inode */
++ err = inode_change_ok(lower_inode, ia);
++ if (err)
++ goto out;
++
++ /* copyup if the file is on a read only branch */
++ if (is_robranch_super(dentry->d_sb, bstart)
++ || __is_rdonly(lower_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(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/inode 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 */
++ /*
++ * Note: we use lower_dentry->d_inode, because lower_inode may be
++ * unlinked (no inode->i_sb and i_ino==0. This happens if someone
++ * tries to open(), unlink(), then ftruncate() a file.
++ */
++ 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 */
++ if (ibstart(inode) >= 0)
++ 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_unlock_parent(dentry, parent);
++ 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..b63c17e
+--- /dev/null
++++ b/fs/unionfs/lookup.c
+@@ -0,0 +1,569 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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_lck_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 *parent)
++{
++ struct dentry *tmp;
++ int err = -ENOSYS;
++
++ tmp = unionfs_lookup_full(dentry, parent, 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 dentry *parent, 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 *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);
++ verify_locked(parent);
++
++ /* must initialize dentry operations */
++ dentry->d_op = &unionfs_dops;
++
++ /* We never partial lookup the root directory. */
++ if (IS_ROOT(dentry))
++ goto out;
++
++ 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);
++ bend = dbend(parent);
++ bopaque = dbopaque(parent);
++ 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, 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, 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);
++ if (!lower_mnt)
++ lower_mnt = unionfs_mntget(dentry->d_sb->s_root,
++ bindex);
++ 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->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, 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_lck_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);
++ }
++
++ 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..258386e
+--- /dev/null
++++ b/fs/unionfs/main.c
+@@ -0,0 +1,758 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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++)
++ path_put(&lower_root_info->lower_paths[i]);
++
++ 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++)
++ path_put(&lower_root_info->lower_paths[bindex]);
++ }
++
++ 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;
++ d = lower_root_info->lower_paths[bindex].dentry;
++ /* drop refs we took earlier */
++ atomic_dec(&d->d_sb->s_active);
++ path_put(&lower_root_info->lower_paths[bindex]);
++ }
++ 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..1f70535
+--- /dev/null
++++ b/fs/unionfs/mmap.c
+@@ -0,0 +1,89 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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;
++ const 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..f745fbc
+--- /dev/null
++++ b/fs/unionfs/rdstate.c
+@@ -0,0 +1,285 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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..936700e
+--- /dev/null
++++ b/fs/unionfs/rename.c
+@@ -0,0 +1,517 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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,
++ struct dentry *parent, int bindex)
++{
++ struct dentry *lower_dentry;
++ struct dentry *lower_parent;
++ int err = 0;
++
++ verify_locked(dentry);
++
++ lower_parent = unionfs_lower_dentry_idx(parent, bindex);
++
++ 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 dentry *old_parent,
++ struct inode *new_dir, struct dentry *new_dentry,
++ struct dentry *new_parent,
++ 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_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);
++
++ 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);
++
++ 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 dentry *old_parent,
++ struct inode *new_dir,
++ struct dentry *new_dentry,
++ struct dentry *new_parent)
++{
++ int err = 0;
++ int bindex;
++ int old_bstart, old_bend;
++ int new_bstart, new_bend;
++ int do_copyup = -1;
++ int local_err = 0;
++ int eio = 0;
++ int revert = 0;
++
++ old_bstart = dbstart(old_dentry);
++ old_bend = dbend(old_dentry);
++
++ new_bstart = dbstart(new_dentry);
++ new_bend = dbend(new_dentry);
++
++ /* Rename source to destination. */
++ err = __unionfs_rename(old_dir, old_dentry, old_parent,
++ new_dir, new_dentry, new_parent,
++ 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_parent->d_inode,
++ unlink_dir_dentry->d_inode);
++ /* propagate number of hard-links */
++ new_parent->d_inode->i_nlink =
++ unionfs_get_nlinks(new_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_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;
++ /*
++ * create whiteout before calling __unionfs_rename
++ * because the latter will change the old_dentry's
++ * lower name and parent dir, resulting in the
++ * whiteout getting created in the wrong dir.
++ */
++ err = create_whiteout(old_dentry, bindex);
++ if (err) {
++ printk(KERN_ERR "unionfs: can't create a "
++ "whiteout for %s in rename (err=%d)\n",
++ old_dentry->d_name.name, err);
++ continue;
++ }
++ err = __unionfs_rename(old_dir, old_dentry, old_parent,
++ new_dir, new_dentry, new_parent,
++ 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.
++ * (We did a copy_up is taken care of above).
++ */
++ if ((old_bstart != old_bend) && (do_copyup == -1)) {
++ err = create_whiteout(old_dentry, old_bstart);
++ 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, new_parent,
++ 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_parent,
++ 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, new_parent,
++ old_dir, old_dentry, old_parent,
++ 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, new_parent,
++ bindex);
++ if (local_err)
++ eio = -EIO;
++ local_err = unionfs_refresh_lower_dentry(old_dentry, old_parent,
++ 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, struct dentry *parent)
++{
++ int err, bstart;
++
++ err = check_empty(dentry, parent, 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, parent, NULL);
++ dbstart(dentry) = bstart;
++ if (err == -ENOTEMPTY)
++ err = -EXDEV;
++ return err;
++}
++
++/*
++ * The locking rules in unionfs_rename are complex. We could use a simpler
++ * superblock-level name-space lock for renames and copy-ups.
++ */
++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;
++ struct dentry *old_parent, *new_parent;
++ int valid = true;
++
++ unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ old_parent = dget_parent(old_dentry);
++ new_parent = dget_parent(new_dentry);
++ /* un/lock parent dentries only if they differ from old/new_dentry */
++ if (old_parent != old_dentry &&
++ old_parent != new_dentry)
++ unionfs_lock_dentry(old_parent, UNIONFS_DMUTEX_REVAL_PARENT);
++ if (new_parent != old_dentry &&
++ new_parent != new_dentry &&
++ new_parent != old_parent)
++ unionfs_lock_dentry(new_parent, UNIONFS_DMUTEX_REVAL_CHILD);
++ unionfs_double_lock_dentry(old_dentry, new_dentry);
++
++ valid = __unionfs_d_revalidate(old_dentry, old_parent, false);
++ if (!valid) {
++ err = -ESTALE;
++ goto out;
++ }
++ if (!d_deleted(new_dentry) && new_dentry->d_inode) {
++ valid = __unionfs_d_revalidate(new_dentry, new_parent, false);
++ if (!valid) {
++ err = -ESTALE;
++ goto out;
++ }
++ }
++
++ if (!S_ISDIR(old_dentry->d_inode->i_mode))
++ err = unionfs_partial_lookup(old_dentry, old_parent);
++ else
++ err = may_rename_dir(old_dentry, old_parent);
++
++ if (err)
++ goto out;
++
++ err = unionfs_partial_lookup(new_dentry, new_parent);
++ 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, new_parent, &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, old_parent,
++ new_dir, new_dentry, new_parent);
++ 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_double_unlock_dentry(old_dentry, new_dentry);
++ if (new_parent != old_dentry &&
++ new_parent != new_dentry &&
++ new_parent != old_parent)
++ unionfs_unlock_dentry(new_parent);
++ if (old_parent != old_dentry &&
++ old_parent != new_dentry)
++ unionfs_unlock_dentry(old_parent);
++ dput(new_parent);
++ dput(old_parent);
++ 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..760c580
+--- /dev/null
++++ b/fs/unionfs/sioq.c
+@@ -0,0 +1,101 @@
++/*
++ * Copyright (c) 2006-2010 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) 2006-2010 Stony Brook University
++ * Copyright (c) 2006-2010 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..b26d248
+--- /dev/null
++++ b/fs/unionfs/sioq.h
+@@ -0,0 +1,91 @@
++/*
++ * Copyright (c) 2006-2010 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) 2006-2010 Stony Brook University
++ * Copyright (c) 2006-2010 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..570a344
+--- /dev/null
++++ b/fs/unionfs/subr.c
+@@ -0,0 +1,95 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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..45bb9bf
+--- /dev/null
++++ b/fs/unionfs/super.c
+@@ -0,0 +1,1029 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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;
++}
++
++/*
++ * 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;
++ }
++ WARN_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;
++ struct dentry *parent;
++ struct path lower_path;
++ bool valid;
++
++ sb = dentry->d_sb;
++
++ unionfs_read_lock(sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ err = -ESTALE;
++ goto out;
++ }
++ unionfs_check_dentry(dentry);
++
++ lower_dentry = unionfs_lower_dentry(sb->s_root);
++ lower_path.dentry = lower_dentry;
++ lower_path.mnt = unionfs_mntget(sb->s_root, 0);
++ err = vfs_statfs(&lower_path, buf);
++ mntput(lower_path.mnt);
++
++ /* 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_unlock_parent(dentry, parent);
++ 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_evict_inode(struct inode *inode)
++{
++ int bindex, bstart, bend;
++ struct inode *lower_inode;
++ struct list_head *pos, *n;
++ struct unionfs_dir_state *rdstate;
++
++ truncate_inode_pages(&inode->i_data, 0);
++ end_writeback(inode);
++
++ 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,
++ struct writeback_control *wbc)
++{
++ 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 = {
++ .put_super = unionfs_put_super,
++ .statfs = unionfs_statfs,
++ .remount_fs = unionfs_remount_fs,
++ .evict_inode = unionfs_evict_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..d49c834
+--- /dev/null
++++ b/fs/unionfs/union.h
+@@ -0,0 +1,669 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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 */
++ const 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(d1, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(d2, UNIONFS_DMUTEX_CHILD);
++ } else {
++ unionfs_lock_dentry(d2, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(d1, UNIONFS_DMUTEX_CHILD);
++ }
++}
++
++static inline void unionfs_double_unlock_dentry(struct dentry *d1,
++ struct dentry *d2)
++{
++ BUG_ON(d1 == d2);
++ if (d1 < d2) { /* unlock in reverse order than double_lock_dentry */
++ unionfs_unlock_dentry(d1);
++ unionfs_unlock_dentry(d2);
++ } else {
++ unionfs_unlock_dentry(d2);
++ unionfs_unlock_dentry(d1);
++ }
++}
++
++static inline void unionfs_double_lock_parents(struct dentry *p1,
++ struct dentry *p2)
++{
++ if (p1 == p2) {
++ unionfs_lock_dentry(p1, UNIONFS_DMUTEX_REVAL_PARENT);
++ return;
++ }
++ if (p1 < p2) {
++ unionfs_lock_dentry(p1, UNIONFS_DMUTEX_REVAL_PARENT);
++ unionfs_lock_dentry(p2, UNIONFS_DMUTEX_REVAL_CHILD);
++ } else {
++ unionfs_lock_dentry(p2, UNIONFS_DMUTEX_REVAL_PARENT);
++ unionfs_lock_dentry(p1, UNIONFS_DMUTEX_REVAL_CHILD);
++ }
++}
++
++static inline void unionfs_double_unlock_parents(struct dentry *p1,
++ struct dentry *p2)
++{
++ if (p1 == p2) {
++ unionfs_unlock_dentry(p1);
++ return;
++ }
++ if (p1 < p2) { /* unlock in reverse order of double_lock_parents */
++ unionfs_unlock_dentry(p1);
++ unionfs_unlock_dentry(p2);
++ } else {
++ unionfs_unlock_dentry(p2);
++ unionfs_unlock_dentry(p1);
++ }
++}
++
++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,
++ struct dentry *parent);
++extern struct dentry *unionfs_lookup_full(struct dentry *dentry,
++ struct dentry *parent,
++ 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 dentry *parent,
++ 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, struct dentry *parent,
++ 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, 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(struct dentry *dentry,
++ struct dentry *parent, 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;
++}
++
++/* check if readonly lower inode, but possibly unlinked (no inode->i_sb) */
++static inline int __is_rdonly(const struct inode *inode)
++{
++ /* if unlinked, can't be readonly (?) */
++ if (!inode->i_sb)
++ return 0;
++ return IS_RDONLY(inode);
++
++}
++/* 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);
++}
++
++/* lock base inode mutex before calling lookup_one_len */
++static inline struct dentry *lookup_lck_len(const char *name,
++ struct dentry *base, int len)
++{
++ struct dentry *d;
++ mutex_lock(&base->d_inode->i_mutex);
++ d = lookup_one_len(name, base, len);
++ mutex_unlock(&base->d_inode->i_mutex);
++ return d;
++}
++
++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..542c513
+--- /dev/null
++++ b/fs/unionfs/unlink.c
+@@ -0,0 +1,278 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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 *parent)
++{
++ struct dentry *lower_dentry;
++ struct dentry *lower_dir_dentry;
++ int bindex;
++ int err = 0;
++
++ err = unionfs_partial_lookup(dentry, parent);
++ 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;
++ struct dentry *parent;
++ int valid;
++
++ BUG_ON(S_ISDIR(inode->i_mode));
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ err = -ESTALE;
++ goto out;
++ }
++ unionfs_check_dentry(dentry);
++
++ err = unionfs_unlink_whiteout(dir, dentry, parent);
++ /* call d_drop so the system "forgets" about us */
++ if (!err) {
++ unionfs_postcopyup_release(dentry);
++ unionfs_postcopyup_setmnt(parent);
++ 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);
++ unionfs_unlock_parent(dentry, parent);
++ 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)
++ err = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
++ 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;
++ struct dentry *parent;
++ int dstart, dend;
++ bool valid;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ err = -ESTALE;
++ goto out;
++ }
++ unionfs_check_dentry(dentry);
++
++ /* check if this unionfs directory is empty or not */
++ err = check_empty(dentry, parent, &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);
++ unionfs_check_dentry(dentry);
++ unionfs_check_inode(dir);
++ }
++
++ if (namelist)
++ free_rdstate(namelist);
++
++ unionfs_unlock_dentry(dentry);
++ unionfs_unlock_parent(dentry, parent);
++ 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..405073a
+--- /dev/null
++++ b/fs/unionfs/whiteout.c
+@@ -0,0 +1,584 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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_lck_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);
++
++ 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);
++ }
++
++ 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_dir_dentry->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_lck_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_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_lck_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;
++ const struct cred *old_creds;
++ struct cred *new_creds;
++
++ /*
++ * 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).
++ */
++ new_creds = prepare_creds();
++ if (unlikely(!new_creds)) {
++ err = -ENOMEM;
++ goto out_err;
++ }
++ cap_raise(new_creds->cap_effective, CAP_DAC_READ_SEARCH);
++ cap_raise(new_creds->cap_effective, CAP_DAC_OVERRIDE);
++ old_creds = override_creds(new_creds);
++
++ 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);
++ revert_creds(old_creds);
++out_err:
++ return err;
++}
+diff --git a/fs/unionfs/xattr.c b/fs/unionfs/xattr.c
+new file mode 100644
+index 0000000..9002e06
+--- /dev/null
++++ b/fs/unionfs/xattr.c
+@@ -0,0 +1,173 @@
++/*
++ * Copyright (c) 2003-2010 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) 2003-2010 Stony Brook University
++ * Copyright (c) 2003-2010 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;
++ struct dentry *parent;
++ int err = -EOPNOTSUPP;
++ bool valid;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ 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_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++ int err = -EOPNOTSUPP;
++ bool valid;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ 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_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++ int err = -EOPNOTSUPP;
++ bool valid;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ 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_unlock_parent(dentry, parent);
++ 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;
++ struct dentry *parent;
++ int err = -EOPNOTSUPP;
++ char *encoded_list = NULL;
++ bool valid;
++
++ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
++ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
++ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
++
++ valid = __unionfs_d_revalidate(dentry, parent, false);
++ if (unlikely(!valid)) {
++ 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_unlock_parent(dentry, parent);
++ unionfs_read_unlock(dentry->d_sb);
++ return err;
++}
+diff --git a/include/linux/fs_stack.h b/include/linux/fs_stack.h
+index da317c7..64f1ced 100644
+--- a/include/linux/fs_stack.h
++++ b/include/linux/fs_stack.h
+@@ -1,7 +1,19 @@
++/*
++ * Copyright (c) 2006-2009 Erez Zadok
++ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
++ * Copyright (c) 2006-2009 Stony Brook University
++ * Copyright (c) 2006-2009 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.
+ */
+
+diff --git a/include/linux/magic.h b/include/linux/magic.h
+index eb9800f..9770154 100644
+--- a/include/linux/magic.h
++++ b/include/linux/magic.h
+@@ -47,6 +47,8 @@
+ #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/namei.h b/include/linux/namei.h
+index 05b441d..dca6f9a 100644
+--- a/include/linux/namei.h
++++ b/include/linux/namei.h
+@@ -72,6 +72,7 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
+
+ extern struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
+ int (*open)(struct inode *, struct file *));
++extern void release_open_intent(struct nameidata *);
+
+ extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
+
+diff --git a/include/linux/splice.h b/include/linux/splice.h
+index 997c3b4..54f5501 100644
+--- a/include/linux/splice.h
++++ b/include/linux/splice.h
+@@ -81,6 +81,11 @@ 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);
+
+ /*
+ * for dynamic pipe sizing
+diff --git a/include/linux/union_fs.h b/include/linux/union_fs.h
+new file mode 100644
+index 0000000..c84d97e
+--- /dev/null
++++ b/include/linux/union_fs.h
+@@ -0,0 +1,22 @@
++/*
++ * Copyright (c) 2003-2009 Erez Zadok
++ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
++ * Copyright (c) 2003-2009 Stony Brook University
++ * Copyright (c) 2003-2009 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 */
++
+diff --git a/security/security.c b/security/security.c
+index c53949f..eb71394 100644
+--- a/security/security.c
++++ b/security/security.c
+@@ -528,6 +528,7 @@ int security_inode_permission(struct inode *inode, int mask)
+ return 0;
+ return security_ops->inode_permission(inode, mask);
+ }
++EXPORT_SYMBOL(security_inode_permission);
+
+ int security_inode_setattr(struct dentry *dentry, struct iattr *attr)
+ {