genode/ports-okl4/patches/unionfs.patch
2011-12-22 16:19:25 +01:00

11420 lines
332 KiB
Diff

diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
index 59db1bc..40816d4 100644
--- a/Documentation/filesystems/00-INDEX
+++ b/Documentation/filesystems/00-INDEX
@@ -86,6 +86,8 @@ 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 9a91d9e..87e1e63 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3740,6 +3740,14 @@ L: linux-kernel@vger.kernel.org
W: http://www.kernel.dk
S: Maintained
+UNIONFS
+P: Erez Zadok
+M: ezk@cs.sunysb.edu
+L: unionfs@filesystems.org
+W: http://unionfs.filesystems.org
+T: git git.kernel.org/pub/scm/linux/kernel/git/ezk/unionfs.git
+S: Maintained
+
USB ACM DRIVER
P: Oliver Neukum
M: oliver@neukum.name
diff --git a/fs/Kconfig b/fs/Kconfig
index f9eed6d..9afb8df 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -1027,6 +1027,47 @@ config CONFIGFS_FS
endmenu
+menu "Layered filesystems"
+
+config ECRYPT_FS
+ tristate "eCrypt filesystem layer support (EXPERIMENTAL)"
+ depends on EXPERIMENTAL && KEYS && CRYPTO && NET
+ help
+ Encrypted filesystem that operates on the VFS layer. See
+ <file:Documentation/ecryptfs.txt> to learn more about
+ eCryptfs. Userspace components are required and can be
+ obtained from <http://ecryptfs.sf.net>.
+
+ To compile this file system support as a module, choose M here: the
+ module will be called ecryptfs.
+
+config UNION_FS
+ tristate "Union file system (EXPERIMENTAL)"
+ depends on EXPERIMENTAL
+ help
+ Unionfs is a stackable unification file system, which appears to
+ merge the contents of several directories (branches), while keeping
+ their physical content separate.
+
+ See <http://unionfs.filesystems.org> for details
+
+config UNION_FS_XATTR
+ bool "Unionfs extended attributes"
+ depends on UNION_FS
+ help
+ Extended attributes are name:value pairs associated with inodes by
+ the kernel or by users (see the attr(5) manual page).
+
+ If unsure, say N.
+
+config UNION_FS_DEBUG
+ bool "Debug Unionfs"
+ depends on UNION_FS
+ help
+ If you say Y here, you can turn on debugging output from Unionfs.
+
+endmenu
+
menu "Miscellaneous filesystems"
config ADFS_FS
@@ -1079,18 +1120,6 @@ config AFFS_FS
To compile this file system support as a module, choose M here: the
module will be called affs. If unsure, say N.
-config ECRYPT_FS
- tristate "eCrypt filesystem layer support (EXPERIMENTAL)"
- depends on EXPERIMENTAL && KEYS && CRYPTO && NET
- help
- Encrypted filesystem that operates on the VFS layer. See
- <file:Documentation/ecryptfs.txt> to learn more about
- eCryptfs. Userspace components are required and can be
- obtained from <http://ecryptfs.sf.net>.
-
- To compile this file system support as a module, choose M here: the
- module will be called ecryptfs.
-
config HFS_FS
tristate "Apple Macintosh file system support (EXPERIMENTAL)"
depends on BLOCK && EXPERIMENTAL
diff --git a/fs/Makefile b/fs/Makefile
index 720c29d..f1301f3 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/ecryptfs/dentry.c b/fs/ecryptfs/dentry.c
index cb20b96..a8c1686 100644
--- a/fs/ecryptfs/dentry.c
+++ b/fs/ecryptfs/dentry.c
@@ -62,7 +62,7 @@ static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
struct inode *lower_inode =
ecryptfs_inode_to_lower(dentry->d_inode);
- fsstack_copy_attr_all(dentry->d_inode, lower_inode, NULL);
+ fsstack_copy_attr_all(dentry->d_inode, lower_inode);
}
out:
return rc;
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 131954b..fc4c6cb 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -601,9 +601,9 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
lower_new_dir_dentry->d_inode, lower_new_dentry);
if (rc)
goto out_lock;
- fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
+ fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
if (new_dir != old_dir)
- fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
+ fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
out_lock:
unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
dput(lower_new_dentry->d_parent);
@@ -961,7 +961,7 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
}
rc = notify_change(lower_dentry, ia);
out:
- fsstack_copy_attr_all(inode, lower_inode, NULL);
+ fsstack_copy_attr_all(inode, lower_inode);
return rc;
}
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index a984972..cb349a4 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -151,7 +151,7 @@ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
d_add(dentry, inode);
else
d_instantiate(dentry, inode);
- fsstack_copy_attr_all(inode, lower_inode, NULL);
+ fsstack_copy_attr_all(inode, lower_inode);
/* This size will be overwritten for real files w/ headers and
* other metadata */
fsstack_copy_inode_size(inode, lower_inode);
diff --git a/fs/namei.c b/fs/namei.c
index 314afe6..c15ce85 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -374,6 +374,7 @@ 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 1a9c0e6..f931be4 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -943,8 +943,8 @@ EXPORT_SYMBOL(generic_splice_sendpage);
/*
* Attempt to initiate a splice from pipe to file.
*/
-static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
- loff_t *ppos, size_t len, unsigned int flags)
+long vfs_splice_from(struct pipe_inode_info *pipe, struct file *out,
+ loff_t *ppos, size_t len, unsigned int flags)
{
int ret;
@@ -964,13 +964,14 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
return out->f_op->splice_write(pipe, out, ppos, len, flags);
}
+EXPORT_SYMBOL_GPL(vfs_splice_from);
/*
* Attempt to initiate a splice from a file to a pipe.
*/
-static long do_splice_to(struct file *in, loff_t *ppos,
- struct pipe_inode_info *pipe, size_t len,
- unsigned int flags)
+long vfs_splice_to(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
{
int ret;
@@ -990,6 +991,7 @@ static long do_splice_to(struct file *in, loff_t *ppos,
return in->f_op->splice_read(in, ppos, pipe, len, flags);
}
+EXPORT_SYMBOL_GPL(vfs_splice_to);
/**
* splice_direct_to_actor - splices data directly between two non-pipes
@@ -1059,7 +1061,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
size_t read_len;
loff_t pos = sd->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;
@@ -1117,7 +1119,7 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
{
struct file *file = sd->u.file;
- return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags);
+ return vfs_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags);
}
/**
@@ -1191,7 +1193,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
} else
off = &out->f_pos;
- ret = do_splice_from(pipe, out, off, len, flags);
+ ret = vfs_splice_from(pipe, out, off, len, flags);
if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
ret = -EFAULT;
@@ -1212,7 +1214,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
} else
off = &in->f_pos;
- ret = do_splice_to(in, off, pipe, len, flags);
+ ret = vfs_splice_to(in, off, pipe, len, flags);
if (off_in && copy_to_user(off_in, off, sizeof(loff_t)))
ret = -EFAULT;
diff --git a/fs/stack.c b/fs/stack.c
index 67716f6..cc1443d 100644
--- a/fs/stack.c
+++ b/fs/stack.c
@@ -1,24 +1,82 @@
+/*
+ * 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
*/
-void fsstack_copy_inode_size(struct inode *dst, const struct inode *src)
+void fsstack_copy_inode_size(struct inode *dst, struct inode *src)
{
- i_size_write(dst, i_size_read((struct inode *)src));
- dst->i_blocks = src->i_blocks;
+ loff_t i_size;
+ blkcnt_t i_blocks;
+
+ /*
+ * i_size_read() includes its own seqlocking and protection from
+ * preemption (see include/linux/fs.h): we need nothing extra for
+ * that here, and prefer to avoid nesting locks than attempt to
+ * keep i_size and i_blocks in synch together.
+ */
+ i_size = i_size_read(src);
+
+ /*
+ * But if CONFIG_LSF (on 32-bit), we ought to make an effort to keep
+ * the two halves of i_blocks in synch despite SMP or PREEMPT - though
+ * stat's generic_fillattr() doesn't bother, and we won't be applying
+ * quotas (where i_blocks does become important) at the upper level.
+ *
+ * We don't actually know what locking is used at the lower level; but
+ * if it's a filesystem that supports quotas, it will be using i_lock
+ * as in inode_add_bytes(). tmpfs uses other locking, and its 32-bit
+ * is (just) able to exceed 2TB i_size with the aid of holes; but its
+ * i_blocks cannot carry into the upper long without almost 2TB swap -
+ * let's ignore that case.
+ */
+ if (sizeof(i_blocks) > sizeof(long))
+ spin_lock(&src->i_lock);
+ i_blocks = src->i_blocks;
+ if (sizeof(i_blocks) > sizeof(long))
+ spin_unlock(&src->i_lock);
+
+ /*
+ * If CONFIG_SMP on 32-bit, it's vital for fsstack_copy_inode_size()
+ * to hold some lock around i_size_write(), otherwise i_size_read()
+ * may spin forever (see include/linux/fs.h). We don't necessarily
+ * hold i_mutex when this is called, so take i_lock for that case.
+ *
+ * And if CONFIG_LSF (on 32-bit), continue our effort to keep the
+ * two halves of i_blocks in synch despite SMP or PREEMPT: use i_lock
+ * for that case too, and do both at once by combining the tests.
+ *
+ * There is none of this locking overhead in the 64-bit case.
+ */
+ if (sizeof(i_size) > sizeof(long) || sizeof(i_blocks) > sizeof(long))
+ spin_lock(&dst->i_lock);
+ i_size_write(dst, i_size);
+ dst->i_blocks = i_blocks;
+ if (sizeof(i_size) > sizeof(long) || sizeof(i_blocks) > sizeof(long))
+ spin_unlock(&dst->i_lock);
}
EXPORT_SYMBOL_GPL(fsstack_copy_inode_size);
-/* copy all attributes; get_nlinks is optional way to override the i_nlink
+/*
+ * copy all attributes; get_nlinks is optional way to override the i_nlink
* copying
*/
-void fsstack_copy_attr_all(struct inode *dest, const struct inode *src,
- int (*get_nlinks)(struct inode *))
+void fsstack_copy_attr_all(struct inode *dest, const struct inode *src)
{
dest->i_mode = src->i_mode;
dest->i_uid = src->i_uid;
@@ -29,14 +87,6 @@ void fsstack_copy_attr_all(struct inode *dest, const struct inode *src,
dest->i_ctime = src->i_ctime;
dest->i_blkbits = src->i_blkbits;
dest->i_flags = src->i_flags;
-
- /*
- * Update the nlinks AFTER updating the above fields, because the
- * get_links callback may depend on them.
- */
- if (!get_nlinks)
- dest->i_nlink = src->i_nlink;
- else
- dest->i_nlink = (*get_nlinks)(dest);
+ dest->i_nlink = src->i_nlink;
}
EXPORT_SYMBOL_GPL(fsstack_copy_attr_all);
diff --git a/fs/unionfs/Makefile b/fs/unionfs/Makefile
new file mode 100644
index 0000000..bbc102d
--- /dev/null
+++ b/fs/unionfs/Makefile
@@ -0,0 +1,17 @@
+UNIONFS_VERSION="2.5.4 (for 2.6.23.17)"
+
+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..be2fa34
--- /dev/null
+++ b/fs/unionfs/commonfops.c
@@ -0,0 +1,879 @@
+/*
+ * 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_one_len(name, lower_dentry->d_parent,
+ nlen);
+ if (IS_ERR(tmp_dentry)) {
+ err = PTR_ERR(tmp_dentry);
+ goto out;
+ }
+ } while (tmp_dentry->d_inode != NULL); /* need negative dentry */
+ dput(tmp_dentry);
+
+ err = copyup_named_file(parent->d_inode, file, name, bstart, bindex,
+ i_size_read(file->f_path.dentry->d_inode));
+ if (err) {
+ if (unlikely(err == -EEXIST))
+ goto retry;
+ goto out;
+ }
+
+ /* bring it to the same state as an unlinked file */
+ lower_dentry = unionfs_lower_dentry_idx(dentry, dbstart(dentry));
+ if (!unionfs_lower_inode_idx(dentry->d_inode, bindex)) {
+ atomic_inc(&lower_dentry->d_inode->i_count);
+ unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
+ lower_dentry->d_inode);
+ }
+ lower_dir_dentry = lock_parent(lower_dentry);
+ err = vfs_unlink(lower_dir_dentry->d_inode, lower_dentry);
+ unlock_dir(lower_dir_dentry);
+
+out:
+ if (!err)
+ unionfs_check_dentry(dentry);
+ return err;
+}
+
+/*
+ * put all references held by upper struct file and free lower file pointer
+ * array
+ */
+static void cleanup_file(struct file *file)
+{
+ int bindex, bstart, bend;
+ struct file **lower_files;
+ struct file *lower_file;
+ struct super_block *sb = file->f_path.dentry->d_sb;
+
+ lower_files = UNIONFS_F(file)->lower_files;
+ bstart = fbstart(file);
+ bend = fbend(file);
+
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ int i; /* holds (possibly) updated branch index */
+ int old_bid;
+
+ lower_file = unionfs_lower_file_idx(file, bindex);
+ if (!lower_file)
+ continue;
+
+ /*
+ * Find new index of matching branch with an open
+ * file, since branches could have been added or
+ * deleted causing the one with open files to shift.
+ */
+ old_bid = UNIONFS_F(file)->saved_branch_ids[bindex];
+ i = branch_id_to_idx(sb, old_bid);
+ if (unlikely(i < 0)) {
+ printk(KERN_ERR "unionfs: no superblock for "
+ "file %p\n", file);
+ continue;
+ }
+
+ /* decrement count of open files */
+ branchput(sb, i);
+ /*
+ * fput will perform an mntput for us on the correct branch.
+ * Although we're using the file's old branch configuration,
+ * bindex, which is the old index, correctly points to the
+ * right branch in the file's branch list. In other words,
+ * we're going to mntput the correct branch even if branches
+ * have been added/removed.
+ */
+ fput(lower_file);
+ UNIONFS_F(file)->lower_files[bindex] = NULL;
+ UNIONFS_F(file)->saved_branch_ids[bindex] = -1;
+ }
+
+ UNIONFS_F(file)->lower_files = NULL;
+ kfree(lower_files);
+ kfree(UNIONFS_F(file)->saved_branch_ids);
+ /* set to NULL because caller needs to know if to kfree on error */
+ UNIONFS_F(file)->saved_branch_ids = NULL;
+}
+
+/* open all lower files for a given file */
+static int open_all_files(struct file *file)
+{
+ int bindex, bstart, bend, err = 0;
+ struct file *lower_file;
+ struct dentry *lower_dentry;
+ struct dentry *dentry = file->f_path.dentry;
+ struct super_block *sb = dentry->d_sb;
+
+ bstart = dbstart(dentry);
+ bend = dbend(dentry);
+
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
+ if (!lower_dentry)
+ continue;
+
+ dget(lower_dentry);
+ unionfs_mntget(dentry, bindex);
+ branchget(sb, bindex);
+
+ lower_file =
+ dentry_open(lower_dentry,
+ unionfs_lower_mnt_idx(dentry, bindex),
+ file->f_flags);
+ if (IS_ERR(lower_file)) {
+ 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);
+ 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);
+ 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);
+ 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;
+
+ 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);
+ return err;
+}
+
+/* pass the ioctl to the lower fs */
+static long do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct file *lower_file;
+ int err;
+
+ lower_file = unionfs_lower_file(file);
+
+ err = -ENOTTY;
+ if (!lower_file || !lower_file->f_op)
+ goto out;
+ if (lower_file->f_op->unlocked_ioctl) {
+ err = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
+ } else if (lower_file->f_op->ioctl) {
+ lock_kernel();
+ err = lower_file->f_op->ioctl(
+ lower_file->f_path.dentry->d_inode,
+ lower_file, cmd, arg);
+ unlock_kernel();
+ }
+
+out:
+ return err;
+}
+
+/*
+ * return to user-space the branch indices containing the file in question
+ *
+ * We use fd_set and therefore we are limited to the number of the branches
+ * to FD_SETSIZE, which is currently 1024 - plenty for most people
+ */
+static int unionfs_ioctl_queryfile(struct file *file, 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..297e4ad
--- /dev/null
+++ b/fs/unionfs/copyup.c
@@ -0,0 +1,889 @@
+/*
+ * 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)) {
+ cap_raise(current->cap_effective, CAP_FOWNER);
+ err = vfs_setxattr(new_lower_dentry, name_list,
+ attr_value, size, 0);
+ cap_lower(current->cap_effective, CAP_FOWNER);
+ }
+ if (err < 0)
+ goto out;
+ name_list += strlen(name_list) + 1;
+ }
+out:
+ unionfs_xattr_kfree(name_list_buf);
+ unionfs_xattr_kfree(attr_value);
+ /* Ignore if xattr isn't supported */
+ if (err == -ENOTSUPP || err == -EOPNOTSUPP)
+ err = 0;
+ return err;
+}
+#endif /* CONFIG_UNION_FS_XATTR */
+
+/*
+ * Determine the mode based on the copyup flags, and the existing dentry.
+ *
+ * Handle file systems which may not support certain options. For example
+ * jffs2 doesn't allow one to chmod a symlink. So we ignore such harmless
+ * errors, rather than propagating them up, which results in copyup errors
+ * and errors returned back to users.
+ */
+static int copyup_permissions(struct super_block *sb,
+ struct dentry *old_lower_dentry,
+ struct dentry *new_lower_dentry)
+{
+ struct inode *i = old_lower_dentry->d_inode;
+ struct iattr newattrs;
+ int err;
+
+ newattrs.ia_atime = i->i_atime;
+ newattrs.ia_mtime = i->i_mtime;
+ newattrs.ia_ctime = i->i_ctime;
+ newattrs.ia_gid = i->i_gid;
+ newattrs.ia_uid = i->i_uid;
+ newattrs.ia_valid = ATTR_CTIME | ATTR_ATIME | ATTR_MTIME |
+ ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_FORCE |
+ ATTR_GID | ATTR_UID;
+ mutex_lock(&new_lower_dentry->d_inode->i_mutex);
+ err = notify_change(new_lower_dentry, &newattrs);
+ if (err)
+ goto out;
+
+ /* now try to change the mode and ignore EOPNOTSUPP on symlinks */
+ newattrs.ia_mode = i->i_mode;
+ newattrs.ia_valid = ATTR_MODE | ATTR_FORCE;
+ err = notify_change(new_lower_dentry, &newattrs);
+ if (err == -EOPNOTSUPP &&
+ S_ISLNK(new_lower_dentry->d_inode->i_mode)) {
+ printk(KERN_WARNING
+ "unionfs: changing \"%s\" symlink mode unsupported\n",
+ new_lower_dentry->d_name.name);
+ err = 0;
+ }
+
+out:
+ mutex_unlock(&new_lower_dentry->d_inode->i_mutex);
+ return err;
+}
+
+/*
+ * create the new device/file/directory - use copyup_permission to copyup
+ * times, and mode
+ *
+ * if the object being copied up is a regular file, the file is only created,
+ * the contents have to be copied up separately
+ */
+static int __copyup_ndentry(struct dentry *old_lower_dentry,
+ struct dentry *new_lower_dentry,
+ struct dentry *new_lower_parent_dentry,
+ char *symbuf)
+{
+ int err = 0;
+ umode_t old_mode = old_lower_dentry->d_inode->i_mode;
+ struct sioq_args args;
+
+ if (S_ISDIR(old_mode)) {
+ args.mkdir.parent = new_lower_parent_dentry->d_inode;
+ args.mkdir.dentry = new_lower_dentry;
+ args.mkdir.mode = old_mode;
+
+ run_sioq(__unionfs_mkdir, &args);
+ err = args.err;
+ } else if (S_ISLNK(old_mode)) {
+ args.symlink.parent = new_lower_parent_dentry->d_inode;
+ args.symlink.dentry = new_lower_dentry;
+ args.symlink.symbuf = symbuf;
+ args.symlink.mode = old_mode;
+
+ run_sioq(__unionfs_symlink, &args);
+ err = args.err;
+ } else if (S_ISBLK(old_mode) || S_ISCHR(old_mode) ||
+ S_ISFIFO(old_mode) || S_ISSOCK(old_mode)) {
+ args.mknod.parent = new_lower_parent_dentry->d_inode;
+ args.mknod.dentry = new_lower_dentry;
+ args.mknod.mode = old_mode;
+ args.mknod.dev = old_lower_dentry->d_inode->i_rdev;
+
+ run_sioq(__unionfs_mknod, &args);
+ err = args.err;
+ } else if (S_ISREG(old_mode)) {
+ struct nameidata nd;
+ err = init_lower_nd(&nd, LOOKUP_CREATE);
+ if (unlikely(err < 0))
+ goto out;
+ args.create.nd = &nd;
+ args.create.parent = new_lower_parent_dentry->d_inode;
+ args.create.dentry = new_lower_dentry;
+ args.create.mode = old_mode;
+
+ run_sioq(__unionfs_create, &args);
+ err = args.err;
+ release_lower_nd(&nd, err);
+ } else {
+ printk(KERN_CRIT "unionfs: unknown inode type %d\n",
+ old_mode);
+ BUG();
+ }
+
+out:
+ return err;
+}
+
+static int __copyup_reg_data(struct dentry *dentry,
+ struct dentry *new_lower_dentry, int new_bindex,
+ struct dentry *old_lower_dentry, int old_bindex,
+ struct file **copyup_file, loff_t len)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct file *input_file;
+ struct file *output_file;
+ struct vfsmount *output_mnt;
+ mm_segment_t old_fs;
+ char *buf = NULL;
+ ssize_t read_bytes, write_bytes;
+ loff_t size;
+ int err = 0;
+
+ /* open old file */
+ unionfs_mntget(dentry, old_bindex);
+ branchget(sb, old_bindex);
+ /* dentry_open calls dput and mntput if it returns an error */
+ input_file = dentry_open(old_lower_dentry,
+ unionfs_lower_mnt_idx(dentry, old_bindex),
+ O_RDONLY | O_LARGEFILE);
+ if (IS_ERR(input_file)) {
+ dput(old_lower_dentry);
+ err = PTR_ERR(input_file);
+ goto out;
+ }
+ if (unlikely(!input_file->f_op || !input_file->f_op->read)) {
+ err = -EINVAL;
+ goto out_close_in;
+ }
+
+ /* open new file */
+ dget(new_lower_dentry);
+ output_mnt = unionfs_mntget(sb->s_root, new_bindex);
+ branchget(sb, new_bindex);
+ output_file = dentry_open(new_lower_dentry, output_mnt,
+ O_RDWR | O_LARGEFILE);
+ if (IS_ERR(output_file)) {
+ err = PTR_ERR(output_file);
+ goto out_close_in2;
+ }
+ if (unlikely(!output_file->f_op || !output_file->f_op->write)) {
+ err = -EINVAL;
+ goto out_close_out;
+ }
+
+ /* allocating a buffer */
+ buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (unlikely(!buf)) {
+ err = -ENOMEM;
+ goto out_close_out;
+ }
+
+ input_file->f_pos = 0;
+ output_file->f_pos = 0;
+
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+
+ size = len;
+ err = 0;
+ do {
+ if (len >= PAGE_SIZE)
+ size = PAGE_SIZE;
+ else if ((len < PAGE_SIZE) && (len > 0))
+ size = len;
+
+ len -= PAGE_SIZE;
+
+ read_bytes =
+ input_file->f_op->read(input_file,
+ (char __user *)buf, size,
+ &input_file->f_pos);
+ if (read_bytes <= 0) {
+ err = read_bytes;
+ break;
+ }
+
+ /* see Documentation/filesystems/unionfs/issues.txt */
+ lockdep_off();
+ write_bytes =
+ output_file->f_op->write(output_file,
+ (char __user *)buf,
+ read_bytes,
+ &output_file->f_pos);
+ lockdep_on();
+ if ((write_bytes < 0) || (write_bytes < read_bytes)) {
+ err = write_bytes;
+ break;
+ }
+ } while ((read_bytes > 0) && (len > 0));
+
+ set_fs(old_fs);
+
+ kfree(buf);
+
+ if (!err)
+ err = output_file->f_op->fsync(output_file,
+ new_lower_dentry, 0);
+
+ if (err)
+ goto out_close_out;
+
+ if (copyup_file) {
+ *copyup_file = output_file;
+ goto out_close_in;
+ }
+
+out_close_out:
+ fput(output_file);
+
+out_close_in2:
+ branchput(sb, new_bindex);
+
+out_close_in:
+ fput(input_file);
+
+out:
+ branchput(sb, old_bindex);
+
+ return err;
+}
+
+/*
+ * dput the lower references for old and new dentry & clear a lower dentry
+ * pointer
+ */
+static void __clear(struct dentry *dentry, struct dentry *old_lower_dentry,
+ int old_bstart, int old_bend,
+ struct dentry *new_lower_dentry, int new_bindex)
+{
+ /* get rid of the lower dentry and all its traces */
+ unionfs_set_lower_dentry_idx(dentry, new_bindex, NULL);
+ dbstart(dentry) = old_bstart;
+ dbend(dentry) = old_bend;
+
+ dput(new_lower_dentry);
+ dput(old_lower_dentry);
+}
+
+/*
+ * Copy up a dentry to a file of specified name.
+ *
+ * @dir: used to pull the ->i_sb to access other branches
+ * @dentry: the non-negative dentry whose lower_inode we should copy
+ * @bstart: the branch of the lower_inode to copy from
+ * @new_bindex: the branch to create the new file in
+ * @name: the name of the file to create
+ * @namelen: length of @name
+ * @copyup_file: the "struct file" to return (optional)
+ * @len: how many bytes to copy-up?
+ */
+int copyup_dentry(struct inode *dir, struct dentry *dentry, int bstart,
+ int new_bindex, const char *name, int namelen,
+ struct file **copyup_file, loff_t len)
+{
+ struct dentry *new_lower_dentry;
+ struct dentry *old_lower_dentry = NULL;
+ struct super_block *sb;
+ int err = 0;
+ int old_bindex;
+ int old_bstart;
+ int old_bend;
+ struct dentry *new_lower_parent_dentry = NULL;
+ mm_segment_t oldfs;
+ char *symbuf = NULL;
+
+ verify_locked(dentry);
+
+ old_bindex = bstart;
+ old_bstart = dbstart(dentry);
+ old_bend = dbend(dentry);
+
+ BUG_ON(new_bindex < 0);
+ BUG_ON(new_bindex >= old_bindex);
+
+ sb = dir->i_sb;
+
+ err = is_robranch_super(sb, new_bindex);
+ if (err)
+ goto out;
+
+ /* Create the directory structure above this dentry. */
+ new_lower_dentry = create_parents(dir, dentry, name, new_bindex);
+ if (IS_ERR(new_lower_dentry)) {
+ err = PTR_ERR(new_lower_dentry);
+ goto out;
+ }
+
+ old_lower_dentry = unionfs_lower_dentry_idx(dentry, old_bindex);
+ /* we conditionally dput this old_lower_dentry at end of function */
+ dget(old_lower_dentry);
+
+ /* For symlinks, we must read the link before we lock the directory. */
+ if (S_ISLNK(old_lower_dentry->d_inode->i_mode)) {
+
+ symbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+ if (unlikely(!symbuf)) {
+ __clear(dentry, old_lower_dentry,
+ old_bstart, old_bend,
+ new_lower_dentry, new_bindex);
+ err = -ENOMEM;
+ goto out_free;
+ }
+
+ oldfs = get_fs();
+ set_fs(KERNEL_DS);
+ err = old_lower_dentry->d_inode->i_op->readlink(
+ old_lower_dentry,
+ (char __user *)symbuf,
+ PATH_MAX);
+ set_fs(oldfs);
+ if (err < 0) {
+ __clear(dentry, old_lower_dentry,
+ old_bstart, old_bend,
+ new_lower_dentry, new_bindex);
+ goto out_free;
+ }
+ symbuf[err] = '\0';
+ }
+
+ /* Now we lock the parent, and create the object in the new branch. */
+ new_lower_parent_dentry = lock_parent(new_lower_dentry);
+
+ /* create the new inode */
+ err = __copyup_ndentry(old_lower_dentry, new_lower_dentry,
+ new_lower_parent_dentry, symbuf);
+
+ if (err) {
+ __clear(dentry, old_lower_dentry,
+ old_bstart, old_bend,
+ new_lower_dentry, new_bindex);
+ goto out_unlock;
+ }
+
+ /* We actually copyup the file here. */
+ if (S_ISREG(old_lower_dentry->d_inode->i_mode))
+ err = __copyup_reg_data(dentry, new_lower_dentry, new_bindex,
+ old_lower_dentry, old_bindex,
+ copyup_file, len);
+ if (err)
+ goto out_unlink;
+
+ /* Set permissions. */
+ err = copyup_permissions(sb, old_lower_dentry, new_lower_dentry);
+ if (err)
+ goto out_unlink;
+
+#ifdef CONFIG_UNION_FS_XATTR
+ /* Selinux uses extended attributes for permissions. */
+ err = copyup_xattrs(old_lower_dentry, new_lower_dentry);
+ if (err)
+ goto out_unlink;
+#endif /* CONFIG_UNION_FS_XATTR */
+
+ /* do not allow files getting deleted to be re-interposed */
+ if (!d_deleted(dentry))
+ unionfs_reinterpose(dentry);
+
+ goto out_unlock;
+
+out_unlink:
+ /*
+ * copyup failed, because we possibly ran out of space or
+ * quota, or something else happened so let's unlink; we don't
+ * really care about the return value of vfs_unlink
+ */
+ vfs_unlink(new_lower_parent_dentry->d_inode, new_lower_dentry);
+
+ if (copyup_file) {
+ /* need to close the file */
+
+ fput(*copyup_file);
+ branchput(sb, new_bindex);
+ }
+
+ /*
+ * TODO: should we reset the error to something like -EIO?
+ *
+ * If we don't reset, the user may get some nonsensical errors, but
+ * on the other hand, if we reset to EIO, we guarantee that the user
+ * will get a "confusing" error message.
+ */
+
+out_unlock:
+ unlock_dir(new_lower_parent_dentry);
+
+out_free:
+ /*
+ * If old_lower_dentry was not a file, then we need to dput it. If
+ * it was a file, then it was already dput indirectly by other
+ * functions we call above which operate on regular files.
+ */
+ if (old_lower_dentry && old_lower_dentry->d_inode &&
+ !S_ISREG(old_lower_dentry->d_inode->i_mode))
+ dput(old_lower_dentry);
+ kfree(symbuf);
+
+ if (err) {
+ /*
+ * 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_one_len(childname, lower_parent_dentry,
+ childnamelen);
+ if (IS_ERR(lower_dentry))
+ goto out;
+ } else {
+ /*
+ * Is the name a whiteout of the child name ? lookup the
+ * whiteout child in the underlying file system
+ */
+ lower_dentry = lookup_one_len(name, lower_parent_dentry,
+ strlen(name));
+ if (IS_ERR(lower_dentry))
+ goto out;
+
+ /* Replace the current dentry (if any) with the new one */
+ dput(unionfs_lower_dentry_idx(dentry, bindex));
+ unionfs_set_lower_dentry_idx(dentry, bindex,
+ lower_dentry);
+
+ __cleanup_dentry(dentry, bindex, old_bstart, old_bend);
+ goto out;
+ }
+
+ if (lower_dentry->d_inode) {
+ /*
+ * since this already exists we dput to avoid
+ * multiple references on the same dentry
+ */
+ dput(lower_dentry);
+ } else {
+ struct sioq_args args;
+
+ /* it's a negative dentry, create a new dir */
+ lower_parent_dentry = lock_parent(lower_dentry);
+
+ args.mkdir.parent = lower_parent_dentry->d_inode;
+ args.mkdir.dentry = lower_dentry;
+ args.mkdir.mode = child_dentry->d_inode->i_mode;
+
+ run_sioq(__unionfs_mkdir, &args);
+ err = args.err;
+
+ if (!err)
+ err = copyup_permissions(dir->i_sb, child_dentry,
+ lower_dentry);
+ unlock_dir(lower_parent_dentry);
+ if (err) {
+ dput(lower_dentry);
+ lower_dentry = ERR_PTR(err);
+ goto out;
+ }
+
+ }
+
+ __set_inode(child_dentry, lower_dentry, bindex);
+ __set_dentry(child_dentry, lower_dentry, bindex);
+ /*
+ * update times of this dentry, but also the parent, because if
+ * we changed, the parent may have changed too.
+ */
+ fsstack_copy_attr_times(parent_dentry->d_inode,
+ lower_parent_dentry->d_inode);
+ unionfs_copy_attr_times(child_dentry->d_inode);
+
+ parent_dentry = child_dentry;
+ child_dentry = path[--count];
+ goto begin;
+out:
+ /* cleanup any leftover locks from the do/while loop above */
+ if (IS_ERR(lower_dentry))
+ while (count)
+ dput(path[count--]);
+ kfree(path);
+ return lower_dentry;
+}
+
+/*
+ * Post-copyup helper to ensure we have valid mnts: set lower mnt of
+ * dentry+parents to the first parent node that has an mnt.
+ */
+void unionfs_postcopyup_setmnt(struct dentry *dentry)
+{
+ struct dentry *parent, *hasone;
+ int bindex = dbstart(dentry);
+
+ if (unionfs_lower_mnt_idx(dentry, bindex))
+ return;
+ hasone = dentry->d_parent;
+ /* this loop should stop at root dentry */
+ while (!unionfs_lower_mnt_idx(hasone, bindex))
+ hasone = hasone->d_parent;
+ parent = dentry;
+ while (!unionfs_lower_mnt_idx(parent, bindex)) {
+ unionfs_set_lower_mnt_idx(parent, bindex,
+ unionfs_mntget(hasone, bindex));
+ parent = parent->d_parent;
+ }
+}
+
+/*
+ * Post-copyup helper to release all non-directory source objects of a
+ * copied-up file. Regular files should have only one lower object.
+ */
+void unionfs_postcopyup_release(struct dentry *dentry)
+{
+ int bstart, bend;
+
+ BUG_ON(S_ISDIR(dentry->d_inode->i_mode));
+ bstart = dbstart(dentry);
+ bend = dbend(dentry);
+
+ path_put_lowers(dentry, bstart + 1, bend, false);
+ iput_lowers(dentry->d_inode, bstart + 1, bend, false);
+
+ dbend(dentry) = bstart;
+ ibend(dentry->d_inode) = ibstart(dentry->d_inode) = bstart;
+}
diff --git a/fs/unionfs/debug.c b/fs/unionfs/debug.c
new file mode 100644
index 0000000..c8f3e62
--- /dev/null
+++ b/fs/unionfs/debug.c
@@ -0,0 +1,537 @@
+/*
+ * 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)
+ */
+
+#ifndef KERN_CONT
+# define KERN_CONT ""
+#endif /* not KERN_CONT */
+
+/* it's always useful to know what part of the code called us */
+#define PRINT_CALLER(fname, fxn, line) \
+ do { \
+ if (!printed_caller) { \
+ pr_debug("PC:%s:%s:%d\n", (fname), (fxn), (line)); \
+ printed_caller = 1; \
+ } \
+ } while (0)
+
+/*
+ * __unionfs_check_{inode,dentry,file} perform exhaustive sanity checking on
+ * the fan-out of various Unionfs objects. We check that no lower objects
+ * exist outside the start/end branch range; that all objects within are
+ * non-NULL (with some allowed exceptions); that for every lower file
+ * there's a lower dentry+inode; that the start/end ranges match for all
+ * corresponding lower objects; that open files/symlinks have only one lower
+ * objects, but directories can have several; and more.
+ */
+void __unionfs_check_inode(const struct inode *inode,
+ const char *fname, const char *fxn, int line)
+{
+ int bindex;
+ int istart, iend;
+ struct inode *lower_inode;
+ struct super_block *sb;
+ int printed_caller = 0;
+ void *poison_ptr;
+
+ /* for inodes now */
+ BUG_ON(!inode);
+ sb = inode->i_sb;
+ istart = ibstart(inode);
+ iend = ibend(inode);
+ /* don't check inode if no lower branches */
+ if (istart < 0 && iend < 0)
+ return;
+ if (unlikely(istart > iend)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Ci0: inode=%p istart/end=%d:%d\n",
+ inode, istart, iend);
+ }
+ if (unlikely((istart == -1 && iend != -1) ||
+ (istart != -1 && iend == -1))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Ci1: inode=%p istart/end=%d:%d\n",
+ inode, istart, iend);
+ }
+ if (!S_ISDIR(inode->i_mode)) {
+ if (unlikely(iend != istart)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Ci2: inode=%p istart=%d iend=%d\n",
+ inode, istart, iend);
+ }
+ }
+
+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+ if (unlikely(!UNIONFS_I(inode))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Ci3: no inode_info %p\n", inode);
+ return;
+ }
+ if (unlikely(!UNIONFS_I(inode)->lower_inodes)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Ci4: no lower_inodes %p\n", inode);
+ return;
+ }
+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
+ if (lower_inode) {
+ memset(&poison_ptr, POISON_INUSE, sizeof(void *));
+ if (unlikely(bindex < istart || bindex > iend)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Ci5: inode/linode=%p:%p bindex=%d "
+ "istart/end=%d:%d\n", inode,
+ lower_inode, bindex, istart, iend);
+ } else if (unlikely(lower_inode == poison_ptr)) {
+ /* freed inode! */
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Ci6: inode/linode=%p:%p bindex=%d "
+ "istart/end=%d:%d\n", inode,
+ lower_inode, bindex, istart, iend);
+ }
+ continue;
+ }
+ /* if we get here, then lower_inode == NULL */
+ if (bindex < istart || bindex > iend)
+ continue;
+ /*
+ * directories can have NULL lower inodes in b/t start/end,
+ * but NOT if at the start/end range.
+ */
+ if (unlikely(S_ISDIR(inode->i_mode) &&
+ bindex > istart && bindex < iend))
+ continue;
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Ci7: inode/linode=%p:%p "
+ "bindex=%d istart/end=%d:%d\n",
+ inode, lower_inode, bindex, istart, iend);
+ }
+}
+
+void __unionfs_check_dentry(const struct dentry *dentry,
+ const char *fname, const char *fxn, int line)
+{
+ int bindex;
+ int dstart, dend, istart, iend;
+ struct dentry *lower_dentry;
+ struct inode *inode, *lower_inode;
+ struct super_block *sb;
+ struct vfsmount *lower_mnt;
+ int printed_caller = 0;
+ void *poison_ptr;
+
+ BUG_ON(!dentry);
+ sb = dentry->d_sb;
+ inode = dentry->d_inode;
+ dstart = dbstart(dentry);
+ dend = dbend(dentry);
+ /* don't check dentry/mnt if no lower branches */
+ if (dstart < 0 && dend < 0)
+ goto check_inode;
+ BUG_ON(dstart > dend);
+
+ if (unlikely((dstart == -1 && dend != -1) ||
+ (dstart != -1 && dend == -1))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CD0: dentry=%p dstart/end=%d:%d\n",
+ dentry, dstart, dend);
+ }
+ /*
+ * check for NULL dentries inside the start/end range, or
+ * non-NULL dentries outside the start/end range.
+ */
+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
+ if (lower_dentry) {
+ if (unlikely(bindex < dstart || bindex > dend)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CD1: dentry/lower=%p:%p(%p) "
+ "bindex=%d dstart/end=%d:%d\n",
+ dentry, lower_dentry,
+ (lower_dentry ? lower_dentry->d_inode :
+ (void *) -1L),
+ bindex, dstart, dend);
+ }
+ } else { /* lower_dentry == NULL */
+ if (bindex < dstart || bindex > dend)
+ continue;
+ /*
+ * Directories can have NULL lower inodes in b/t
+ * start/end, but NOT if at the start/end range.
+ * Ignore this rule, however, if this is a NULL
+ * dentry or a deleted dentry.
+ */
+ if (unlikely(!d_deleted((struct dentry *) dentry) &&
+ inode &&
+ !(inode && S_ISDIR(inode->i_mode) &&
+ bindex > dstart && bindex < dend))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CD2: dentry/lower=%p:%p(%p) "
+ "bindex=%d dstart/end=%d:%d\n",
+ dentry, lower_dentry,
+ (lower_dentry ?
+ lower_dentry->d_inode :
+ (void *) -1L),
+ bindex, dstart, dend);
+ }
+ }
+ }
+
+ /* check for vfsmounts same as for dentries */
+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+ lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
+ if (lower_mnt) {
+ if (unlikely(bindex < dstart || bindex > dend)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CM0: dentry/lmnt=%p:%p bindex=%d "
+ "dstart/end=%d:%d\n", dentry,
+ lower_mnt, bindex, dstart, dend);
+ }
+ } else { /* lower_mnt == NULL */
+ if (bindex < dstart || bindex > dend)
+ continue;
+ /*
+ * Directories can have NULL lower inodes in b/t
+ * start/end, but NOT if at the start/end range.
+ * Ignore this rule, however, if this is a NULL
+ * dentry.
+ */
+ if (unlikely(inode &&
+ !(inode && S_ISDIR(inode->i_mode) &&
+ bindex > dstart && bindex < dend))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CM1: dentry/lmnt=%p:%p "
+ "bindex=%d dstart/end=%d:%d\n",
+ dentry, lower_mnt, bindex,
+ dstart, dend);
+ }
+ }
+ }
+
+check_inode:
+ /* for inodes now */
+ if (!inode)
+ return;
+ istart = ibstart(inode);
+ iend = ibend(inode);
+ /* don't check inode if no lower branches */
+ if (istart < 0 && iend < 0)
+ return;
+ BUG_ON(istart > iend);
+ if (unlikely((istart == -1 && iend != -1) ||
+ (istart != -1 && iend == -1))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CI0: dentry/inode=%p:%p istart/end=%d:%d\n",
+ dentry, inode, istart, iend);
+ }
+ if (unlikely(istart != dstart)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CI1: dentry/inode=%p:%p istart=%d dstart=%d\n",
+ dentry, inode, istart, dstart);
+ }
+ if (unlikely(iend != dend)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CI2: dentry/inode=%p:%p iend=%d dend=%d\n",
+ dentry, inode, iend, dend);
+ }
+
+ if (!S_ISDIR(inode->i_mode)) {
+ if (unlikely(dend != dstart)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CI3: dentry/inode=%p:%p dstart=%d dend=%d\n",
+ dentry, inode, dstart, dend);
+ }
+ if (unlikely(iend != istart)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CI4: dentry/inode=%p:%p istart=%d iend=%d\n",
+ dentry, inode, istart, iend);
+ }
+ }
+
+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
+ if (lower_inode) {
+ memset(&poison_ptr, POISON_INUSE, sizeof(void *));
+ if (unlikely(bindex < istart || bindex > iend)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CI5: dentry/linode=%p:%p bindex=%d "
+ "istart/end=%d:%d\n", dentry,
+ lower_inode, bindex, istart, iend);
+ } else if (unlikely(lower_inode == poison_ptr)) {
+ /* freed inode! */
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CI6: dentry/linode=%p:%p bindex=%d "
+ "istart/end=%d:%d\n", dentry,
+ lower_inode, bindex, istart, iend);
+ }
+ continue;
+ }
+ /* if we get here, then lower_inode == NULL */
+ if (bindex < istart || bindex > iend)
+ continue;
+ /*
+ * directories can have NULL lower inodes in b/t start/end,
+ * but NOT if at the start/end range.
+ */
+ if (unlikely(S_ISDIR(inode->i_mode) &&
+ bindex > istart && bindex < iend))
+ continue;
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CI7: dentry/linode=%p:%p "
+ "bindex=%d istart/end=%d:%d\n",
+ dentry, lower_inode, bindex, istart, iend);
+ }
+
+ /*
+ * If it's a directory, then intermediate objects b/t start/end can
+ * be NULL. But, check that all three are NULL: lower dentry, mnt,
+ * and inode.
+ */
+ if (dstart >= 0 && dend >= 0 && S_ISDIR(inode->i_mode))
+ for (bindex = dstart+1; bindex < dend; bindex++) {
+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
+ lower_dentry = unionfs_lower_dentry_idx(dentry,
+ bindex);
+ lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
+ if (unlikely(!((lower_inode && lower_dentry &&
+ lower_mnt) ||
+ (!lower_inode &&
+ !lower_dentry && !lower_mnt)))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" Cx: lmnt/ldentry/linode=%p:%p:%p "
+ "bindex=%d dstart/end=%d:%d\n",
+ lower_mnt, lower_dentry, lower_inode,
+ bindex, dstart, dend);
+ }
+ }
+ /* check if lower inode is newer than upper one (it shouldn't) */
+ if (unlikely(is_newer_lower(dentry) && !is_negative_lower(dentry))) {
+ PRINT_CALLER(fname, fxn, line);
+ for (bindex = ibstart(inode); bindex <= ibend(inode);
+ bindex++) {
+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
+ if (unlikely(!lower_inode))
+ continue;
+ pr_debug(" CI8: bindex=%d mtime/lmtime=%lu.%lu/%lu.%lu "
+ "ctime/lctime=%lu.%lu/%lu.%lu\n",
+ bindex,
+ inode->i_mtime.tv_sec,
+ inode->i_mtime.tv_nsec,
+ lower_inode->i_mtime.tv_sec,
+ lower_inode->i_mtime.tv_nsec,
+ inode->i_ctime.tv_sec,
+ inode->i_ctime.tv_nsec,
+ lower_inode->i_ctime.tv_sec,
+ lower_inode->i_ctime.tv_nsec);
+ }
+ }
+}
+
+void __unionfs_check_file(const struct file *file,
+ const char *fname, const char *fxn, int line)
+{
+ int bindex;
+ int dstart, dend, fstart, fend;
+ struct dentry *dentry;
+ struct file *lower_file;
+ struct inode *inode;
+ struct super_block *sb;
+ int printed_caller = 0;
+
+ BUG_ON(!file);
+ dentry = file->f_path.dentry;
+ sb = dentry->d_sb;
+ dstart = dbstart(dentry);
+ dend = dbend(dentry);
+ BUG_ON(dstart > dend);
+ fstart = fbstart(file);
+ fend = fbend(file);
+ BUG_ON(fstart > fend);
+
+ if (unlikely((fstart == -1 && fend != -1) ||
+ (fstart != -1 && fend == -1))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CF0: file/dentry=%p:%p fstart/end=%d:%d\n",
+ file, dentry, fstart, fend);
+ }
+ if (unlikely(fstart != dstart)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CF1: file/dentry=%p:%p fstart=%d dstart=%d\n",
+ file, dentry, fstart, dstart);
+ }
+ if (unlikely(fend != dend)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CF2: file/dentry=%p:%p fend=%d dend=%d\n",
+ file, dentry, fend, dend);
+ }
+ inode = dentry->d_inode;
+ if (!S_ISDIR(inode->i_mode)) {
+ if (unlikely(fend != fstart)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CF3: file/inode=%p:%p fstart=%d fend=%d\n",
+ file, inode, fstart, fend);
+ }
+ if (unlikely(dend != dstart)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CF4: file/dentry=%p:%p dstart=%d dend=%d\n",
+ file, dentry, dstart, dend);
+ }
+ }
+
+ /*
+ * check for NULL dentries inside the start/end range, or
+ * non-NULL dentries outside the start/end range.
+ */
+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
+ lower_file = unionfs_lower_file_idx(file, bindex);
+ if (lower_file) {
+ if (unlikely(bindex < fstart || bindex > fend)) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CF5: file/lower=%p:%p bindex=%d "
+ "fstart/end=%d:%d\n", file,
+ lower_file, bindex, fstart, fend);
+ }
+ } else { /* lower_file == NULL */
+ if (bindex >= fstart && bindex <= fend) {
+ /*
+ * directories can have NULL lower inodes in
+ * b/t start/end, but NOT if at the
+ * start/end range.
+ */
+ if (unlikely(!(S_ISDIR(inode->i_mode) &&
+ bindex > fstart &&
+ bindex < fend))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CF6: file/lower=%p:%p "
+ "bindex=%d fstart/end=%d:%d\n",
+ file, lower_file, bindex,
+ fstart, fend);
+ }
+ }
+ }
+ }
+
+ __unionfs_check_dentry(dentry, fname, fxn, line);
+}
+
+void __unionfs_check_nd(const struct nameidata *nd,
+ const char *fname, const char *fxn, int line)
+{
+ struct file *file;
+ int printed_caller = 0;
+
+ if (unlikely(!nd))
+ return;
+ if (nd->flags & LOOKUP_OPEN) {
+ file = nd->intent.open.file;
+ if (unlikely(file->f_path.dentry &&
+ strcmp(file->f_path.dentry->d_sb->s_type->name,
+ UNIONFS_NAME))) {
+ PRINT_CALLER(fname, fxn, line);
+ pr_debug(" CND1: lower_file of type %s\n",
+ file->f_path.dentry->d_sb->s_type->name);
+ BUG();
+ }
+ }
+}
+
+/* useful to track vfsmount leaks that could cause EBUSY on unmount */
+void __show_branch_counts(const struct super_block *sb,
+ const char *file, const char *fxn, int line)
+{
+ int i;
+ struct vfsmount *mnt;
+
+ pr_debug("BC:");
+ for (i = 0; i < sbmax(sb); i++) {
+ if (likely(sb->s_root))
+ mnt = UNIONFS_D(sb->s_root)->lower_paths[i].mnt;
+ else
+ mnt = NULL;
+ printk(KERN_CONT "%d:",
+ (mnt ? atomic_read(&mnt->mnt_count) : -99));
+ }
+ printk(KERN_CONT "%s:%s:%d\n", file, fxn, line);
+}
+
+void __show_inode_times(const struct inode *inode,
+ const char *file, const char *fxn, int line)
+{
+ struct inode *lower_inode;
+ int bindex;
+
+ for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
+ if (unlikely(!lower_inode))
+ continue;
+ pr_debug("IT(%lu:%d): %s:%s:%d "
+ "um=%lu/%lu lm=%lu/%lu uc=%lu/%lu lc=%lu/%lu\n",
+ inode->i_ino, bindex,
+ file, fxn, line,
+ inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
+ lower_inode->i_mtime.tv_sec,
+ lower_inode->i_mtime.tv_nsec,
+ inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
+ lower_inode->i_ctime.tv_sec,
+ lower_inode->i_ctime.tv_nsec);
+ }
+}
+
+void __show_dinode_times(const struct dentry *dentry,
+ const char *file, const char *fxn, int line)
+{
+ struct inode *inode = dentry->d_inode;
+ struct inode *lower_inode;
+ int bindex;
+
+ for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
+ if (!lower_inode)
+ continue;
+ pr_debug("DT(%s:%lu:%d): %s:%s:%d "
+ "um=%lu/%lu lm=%lu/%lu uc=%lu/%lu lc=%lu/%lu\n",
+ dentry->d_name.name, inode->i_ino, bindex,
+ file, fxn, line,
+ inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
+ lower_inode->i_mtime.tv_sec,
+ lower_inode->i_mtime.tv_nsec,
+ inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
+ lower_inode->i_ctime.tv_sec,
+ lower_inode->i_ctime.tv_nsec);
+ }
+}
+
+void __show_inode_counts(const struct inode *inode,
+ const char *file, const char *fxn, int line)
+{
+ struct inode *lower_inode;
+ int bindex;
+
+ if (unlikely(!inode)) {
+ pr_debug("SiC: Null inode\n");
+ return;
+ }
+ for (bindex = sbstart(inode->i_sb); bindex <= sbend(inode->i_sb);
+ bindex++) {
+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
+ if (unlikely(!lower_inode))
+ continue;
+ pr_debug("SIC(%lu:%d:%d): lc=%d %s:%s:%d\n",
+ inode->i_ino, bindex,
+ atomic_read(&(inode)->i_count),
+ atomic_read(&(lower_inode)->i_count),
+ file, fxn, line);
+ }
+}
diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
new file mode 100644
index 0000000..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..e9343fd
--- /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);
+ 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..4ec537e
--- /dev/null
+++ b/fs/unionfs/file.c
@@ -0,0 +1,364 @@
+/*
+ * 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;
+ struct vm_operations_struct *saved_vm_ops = NULL;
+
+ 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);
+ return err;
+}
+
+int unionfs_fsync(struct file *file, struct dentry *dentry, int datasync)
+{
+ int bindex, bstart, bend;
+ struct file *lower_file;
+ struct dentry *lower_dentry;
+ struct 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,
+ lower_dentry,
+ datasync);
+ if (!err && bindex == bstart)
+ fsstack_copy_attr_times(inode, lower_inode);
+ mutex_unlock(&lower_inode->i_mutex);
+ if (err)
+ goto out;
+ }
+
+out:
+ if (!err)
+ unionfs_check_file(file);
+ unionfs_unlock_dentry(dentry);
+ unionfs_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,
+ .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..0ece7bc
--- /dev/null
+++ b/fs/unionfs/inode.c
@@ -0,0 +1,1050 @@
+/*
+ * 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, mode);
+ 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;
+
+ 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);
+ unionfs_check_nd(nd);
+ kfree(nd_get_link(nd));
+ 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,
+ struct nameidata *nd)
+{
+ 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, nd);
+ 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),
+ nd);
+}
+
+/*
+ * 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 nameidata *nd)
+{
+ 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);
+
+ if (nd)
+ unionfs_lock_dentry(nd->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, nd);
+ 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);
+ unionfs_check_nd(nd);
+ if (nd)
+ unionfs_unlock_dentry(nd->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;
+
+ 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..020ea83
--- /dev/null
+++ b/fs/unionfs/lookup.c
@@ -0,0 +1,572 @@
+/*
+ * 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.dentry;
+ if (new_mnt)
+ *new_mnt = lower_nd.mnt; /* rc already inc'ed */
+ break;
+ case -ENOENT:
+ /*
+ * We don't consider ENOENT an error, and we want to return
+ * a negative dentry (ala lookup_one_len). As we know
+ * there was no inode for this name before (-ENOENT), then
+ * it's safe to call lookup_one_len (which doesn't take a
+ * vfsmount).
+ */
+ dentry = lookup_one_len(name, base, strlen(name));
+ if (new_mnt)
+ *new_mnt = mntget(lower_nd.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;
+ case LOOKUP_ACCESS:
+ nd->flags = flags;
+ 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_one_len(name, lower_dir_dentry, namelen);
+ if (IS_ERR(lower_dentry)) {
+ err = PTR_ERR(lower_dentry);
+ goto out;
+ }
+ /* XXX: need to mntget/mntput as needed too! */
+ unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
+ /* XXX: wrong mnt for crossing bind mounts! */
+ lower_mnt = unionfs_mntget(dentry->d_sb->s_root, bindex);
+ unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);
+
+ goto out;
+ }
+
+ /* if we're revalidating a positive dentry, don't make it negative */
+ if (lookupmode != INTERPOSE_REVAL)
+ d_add(dentry, NULL);
+
+ goto out;
+
+out_positive:
+ /*** handle POSITIVE dentries ***/
+
+ /*
+ * This unionfs dentry is positive (at least one lower inode
+ * exists), so scan entire dentry from beginning to end, and remove
+ * any negative lower dentries, if any. Then, update dbstart/dbend
+ * to reflect the start/end of positive dentries.
+ */
+ pos_start = pos_end = -1;
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_dentry = unionfs_lower_dentry_idx(dentry,
+ bindex);
+ if (lower_dentry && lower_dentry->d_inode) {
+ if (pos_start < 0)
+ pos_start = bindex;
+ if (bindex > pos_end)
+ pos_end = bindex;
+ continue;
+ }
+ path_put_lowers(dentry, bindex, bindex, false);
+ }
+ if (pos_start >= 0)
+ dbstart(dentry) = pos_start;
+ if (pos_end >= 0)
+ dbend(dentry) = pos_end;
+
+ /* Partial lookups need to re-interpose, or throw away older negs. */
+ if (lookupmode == INTERPOSE_PARTIAL) {
+ if (dentry->d_inode) {
+ unionfs_reinterpose(dentry);
+ goto out;
+ }
+
+ /*
+ * This dentry was positive, so it is as if we had a
+ * negative revalidation.
+ */
+ lookupmode = INTERPOSE_REVAL_NEG;
+ update_bstart(dentry);
+ }
+
+ /*
+ * Interpose can return a dentry if d_splice returned a different
+ * dentry.
+ */
+ d_interposed = unionfs_interpose(dentry, dentry->d_sb, lookupmode);
+ if (IS_ERR(d_interposed))
+ err = PTR_ERR(d_interposed);
+ else if (d_interposed)
+ dentry = d_interposed;
+
+ if (!err)
+ goto out;
+ d_drop(dentry);
+
+out_free:
+ /* should dput/mntput all the underlying dentries on error condition */
+ if (dbstart(dentry) >= 0)
+ path_put_lowers_all(dentry, false);
+ /* free lower_paths unconditionally */
+ kfree(UNIONFS_D(dentry)->lower_paths);
+ UNIONFS_D(dentry)->lower_paths = NULL;
+
+out:
+ if (dentry && UNIONFS_D(dentry)) {
+ BUG_ON(dbstart(dentry) < 0 && dbend(dentry) >= 0);
+ BUG_ON(dbstart(dentry) >= 0 && dbend(dentry) < 0);
+ }
+ if (d_interposed && UNIONFS_D(d_interposed)) {
+ BUG_ON(dbstart(d_interposed) < 0 && dbend(d_interposed) >= 0);
+ BUG_ON(dbstart(d_interposed) >= 0 && dbend(d_interposed) < 0);
+ }
+
+ 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..875c56f
--- /dev/null
+++ b/fs/unionfs/main.c
@@ -0,0 +1,778 @@
+/*
+ * 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 iget.
+ * iget will call our read_inode 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 = iget(sb, iunique(sb, UNIONFS_ROOT_INO));
+ if (!inode) {
+ err = -EACCES;
+ 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->dentry->d_sb->s_type->name, UNIONFS_NAME))
+ return -EINVAL;
+ if (!nd->dentry->d_inode)
+ return -ENOENT;
+ if (!S_ISDIR(nd->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_release(&nd);
+ goto out;
+ }
+
+ lower_root_info->lower_paths[bindex].dentry = nd.dentry;
+ lower_root_info->lower_paths[bindex].mnt = nd.mnt;
+
+ set_branchperms(sb, bindex, perms);
+ set_branch_count(sb, bindex, 0);
+ new_branch_id(sb, bindex);
+
+ if (lower_root_info->bstart < 0)
+ lower_root_info->bstart = bindex;
+ lower_root_info->bend = bindex;
+ bindex++;
+ }
+
+ if (branches == 0) {
+ printk(KERN_ERR "unionfs: no branches specified\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ BUG_ON(branches != (lower_root_info->bend + 1));
+
+ /*
+ * Ensure that no overlaps exist in the branches.
+ *
+ * This test is required because the Linux kernel has no support
+ * currently for ensuring coherency between stackable layers and
+ * branches. If we were to allow overlapping branches, it would be
+ * possible, for example, to delete a file via one branch, which
+ * would not be reflected in another branch. Such incoherency could
+ * lead to inconsistencies and even kernel oopses. Rather than
+ * implement hacks to work around some of these cache-coherency
+ * problems, we prevent branch overlapping, for now. A complete
+ * solution will involve proper kernel/VFS support for cache
+ * coherency, at which time we could safely remove this
+ * branch-overlapping test.
+ */
+ for (i = 0; i < branches; i++) {
+ dent1 = lower_root_info->lower_paths[i].dentry;
+ for (j = i + 1; j < branches; j++) {
+ dent2 = lower_root_info->lower_paths[j].dentry;
+ if (is_branch_overlap(dent1, dent2)) {
+ printk(KERN_ERR "unionfs: branches %d and "
+ "%d overlap\n", i, j);
+ err = -EINVAL;
+ goto out;
+ }
+ }
+ }
+
+out:
+ if (err) {
+ for (i = 0; i < branches; i++)
+ if (lower_root_info->lower_paths[i].dentry) {
+ dput(lower_root_info->lower_paths[i].dentry);
+ /* initialize: can't use unionfs_mntput here */
+ mntput(lower_root_info->lower_paths[i].mnt);
+ }
+
+ kfree(lower_root_info->lower_paths);
+ kfree(UNIONFS_SB(sb)->data);
+
+ /*
+ * MUST clear the pointers to prevent potential double free if
+ * the caller dies later on
+ */
+ lower_root_info->lower_paths = NULL;
+ UNIONFS_SB(sb)->data = NULL;
+ }
+ return err;
+}
+
+/*
+ * Parse mount options. See the manual page for usage instructions.
+ *
+ * Returns the dentry object of the lower-level (lower) directory;
+ * We want to mount our stackable file system on top of that lower directory.
+ */
+static struct unionfs_dentry_info *unionfs_parse_options(
+ struct super_block *sb,
+ char *options)
+{
+ struct unionfs_dentry_info *lower_root_info;
+ char *optname;
+ int err = 0;
+ int bindex;
+ int dirsfound = 0;
+
+ /* allocate private data area */
+ err = -ENOMEM;
+ lower_root_info =
+ kzalloc(sizeof(struct unionfs_dentry_info), GFP_KERNEL);
+ if (unlikely(!lower_root_info))
+ goto out_error;
+ lower_root_info->bstart = -1;
+ lower_root_info->bend = -1;
+ lower_root_info->bopaque = -1;
+
+ while ((optname = strsep(&options, ",")) != NULL) {
+ char *optarg;
+
+ if (!optname || !*optname)
+ continue;
+
+ optarg = strchr(optname, '=');
+ if (optarg)
+ *optarg++ = '\0';
+
+ /*
+ * All of our options take an argument now. Insert ones that
+ * don't, above this check.
+ */
+ if (!optarg) {
+ printk(KERN_ERR "unionfs: %s requires an argument\n",
+ optname);
+ err = -EINVAL;
+ goto out_error;
+ }
+
+ if (!strcmp("dirs", optname)) {
+ if (++dirsfound > 1) {
+ printk(KERN_ERR
+ "unionfs: multiple dirs specified\n");
+ err = -EINVAL;
+ goto out_error;
+ }
+ err = parse_dirs_option(sb, lower_root_info, optarg);
+ if (err)
+ goto out_error;
+ continue;
+ }
+
+ err = -EINVAL;
+ printk(KERN_ERR
+ "unionfs: unrecognized option '%s'\n", optname);
+ goto out_error;
+ }
+ if (dirsfound != 1) {
+ printk(KERN_ERR "unionfs: dirs option required\n");
+ err = -EINVAL;
+ goto out_error;
+ }
+ goto out;
+
+out_error:
+ if (lower_root_info && lower_root_info->lower_paths) {
+ for (bindex = lower_root_info->bstart;
+ bindex >= 0 && bindex <= lower_root_info->bend;
+ bindex++) {
+ struct dentry *d;
+ struct vfsmount *m;
+
+ d = lower_root_info->lower_paths[bindex].dentry;
+ m = lower_root_info->lower_paths[bindex].mnt;
+
+ dput(d);
+ /* initializing: can't use unionfs_mntput here */
+ mntput(m);
+ }
+ }
+
+ kfree(lower_root_info->lower_paths);
+ kfree(lower_root_info);
+
+ kfree(UNIONFS_SB(sb)->data);
+ UNIONFS_SB(sb)->data = NULL;
+
+ lower_root_info = ERR_PTR(err);
+out:
+ return lower_root_info;
+}
+
+/*
+ * our custom d_alloc_root work-alike
+ *
+ * we can't use d_alloc_root if we want to use our own interpose function
+ * unchanged, so we simply call our own "fake" d_alloc_root
+ */
+static struct dentry *unionfs_d_alloc_root(struct super_block *sb)
+{
+ struct dentry *ret = NULL;
+
+ if (sb) {
+ static const struct qstr name = {
+ .name = "/",
+ .len = 1
+ };
+
+ ret = d_alloc(NULL, &name);
+ if (likely(ret)) {
+ ret->d_op = &unionfs_dops;
+ ret->d_sb = sb;
+ ret->d_parent = ret;
+ }
+ }
+ return ret;
+}
+
+/*
+ * There is no need to lock the unionfs_super_info's rwsem as there is no
+ * way anyone can have a reference to the superblock at this point in time.
+ */
+static int unionfs_read_super(struct super_block *sb, void *raw_data,
+ int silent)
+{
+ int err = 0;
+ struct unionfs_dentry_info *lower_root_info = NULL;
+ int bindex, bstart, bend;
+
+ if (!raw_data) {
+ printk(KERN_ERR
+ "unionfs: read_super: missing data argument\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ /* Allocate superblock private data */
+ sb->s_fs_info = kzalloc(sizeof(struct unionfs_sb_info), GFP_KERNEL);
+ if (unlikely(!UNIONFS_SB(sb))) {
+ printk(KERN_CRIT "unionfs: read_super: out of memory\n");
+ err = -ENOMEM;
+ goto out;
+ }
+
+ UNIONFS_SB(sb)->bend = -1;
+ atomic_set(&UNIONFS_SB(sb)->generation, 1);
+ init_rwsem(&UNIONFS_SB(sb)->rwsem);
+ UNIONFS_SB(sb)->high_branch_id = -1; /* -1 == invalid branch ID */
+
+ lower_root_info = unionfs_parse_options(sb, raw_data);
+ if (IS_ERR(lower_root_info)) {
+ printk(KERN_ERR
+ "unionfs: read_super: error while parsing options "
+ "(err = %ld)\n", PTR_ERR(lower_root_info));
+ err = PTR_ERR(lower_root_info);
+ lower_root_info = NULL;
+ goto out_free;
+ }
+ if (lower_root_info->bstart == -1) {
+ err = -ENOENT;
+ goto out_free;
+ }
+
+ /* set the lower superblock field of upper superblock */
+ bstart = lower_root_info->bstart;
+ BUG_ON(bstart != 0);
+ sbend(sb) = bend = lower_root_info->bend;
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ struct dentry *d = lower_root_info->lower_paths[bindex].dentry;
+ atomic_inc(&d->d_sb->s_active);
+ unionfs_set_lower_super_idx(sb, bindex, d->d_sb);
+ }
+
+ /* max Bytes is the maximum bytes from highest priority branch */
+ sb->s_maxbytes = unionfs_lower_super_idx(sb, 0)->s_maxbytes;
+
+ /*
+ * Our c/m/atime granularity is 1 ns because we may stack on file
+ * systems whose granularity is as good. This is important for our
+ * time-based cache coherency.
+ */
+ sb->s_time_gran = 1;
+
+ sb->s_op = &unionfs_sops;
+
+ /* See comment next to the definition of unionfs_d_alloc_root */
+ sb->s_root = unionfs_d_alloc_root(sb);
+ if (unlikely(!sb->s_root)) {
+ err = -ENOMEM;
+ goto out_dput;
+ }
+
+ /* link the upper and lower dentries */
+ sb->s_root->d_fsdata = NULL;
+ err = new_dentry_private_data(sb->s_root, UNIONFS_DMUTEX_ROOT);
+ if (unlikely(err))
+ goto out_freedpd;
+
+ /* Set the lower dentries for s_root */
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ struct dentry *d;
+ struct vfsmount *m;
+
+ d = lower_root_info->lower_paths[bindex].dentry;
+ m = lower_root_info->lower_paths[bindex].mnt;
+
+ unionfs_set_lower_dentry_idx(sb->s_root, bindex, d);
+ unionfs_set_lower_mnt_idx(sb->s_root, bindex, m);
+ }
+ dbstart(sb->s_root) = bstart;
+ dbend(sb->s_root) = bend;
+
+ /* Set the generation number to one, since this is for the mount. */
+ atomic_set(&UNIONFS_D(sb->s_root)->generation, 1);
+
+ /*
+ * Call interpose to create the upper level inode. Only
+ * INTERPOSE_LOOKUP can return a value other than 0 on err.
+ */
+ err = PTR_ERR(unionfs_interpose(sb->s_root, sb, 0));
+ unionfs_unlock_dentry(sb->s_root);
+ if (!err)
+ goto out;
+ /* else fall through */
+
+out_freedpd:
+ if (UNIONFS_D(sb->s_root)) {
+ kfree(UNIONFS_D(sb->s_root)->lower_paths);
+ free_dentry_private_data(sb->s_root);
+ }
+ dput(sb->s_root);
+
+out_dput:
+ if (lower_root_info && !IS_ERR(lower_root_info)) {
+ for (bindex = lower_root_info->bstart;
+ bindex <= lower_root_info->bend; bindex++) {
+ struct dentry *d;
+ struct vfsmount *m;
+
+ d = lower_root_info->lower_paths[bindex].dentry;
+ m = lower_root_info->lower_paths[bindex].mnt;
+
+ dput(d);
+ /* initializing: can't use unionfs_mntput here */
+ mntput(m);
+ /* drop refs we took earlier */
+ atomic_dec(&d->d_sb->s_active);
+ }
+ kfree(lower_root_info->lower_paths);
+ kfree(lower_root_info);
+ lower_root_info = NULL;
+ }
+
+out_free:
+ kfree(UNIONFS_SB(sb)->data);
+ kfree(UNIONFS_SB(sb));
+ sb->s_fs_info = NULL;
+
+out:
+ if (lower_root_info && !IS_ERR(lower_root_info)) {
+ kfree(lower_root_info->lower_paths);
+ kfree(lower_root_info);
+ }
+ return err;
+}
+
+static int unionfs_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *raw_data, struct vfsmount *mnt)
+{
+ int err;
+ err = get_sb_nodev(fs_type, flags, raw_data, unionfs_read_super, mnt);
+ if (!err)
+ UNIONFS_SB(mnt->mnt_sb)->dev_name =
+ kstrdup(dev_name, GFP_KERNEL);
+ return err;
+}
+
+static struct file_system_type unionfs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = UNIONFS_NAME,
+ .get_sb = unionfs_get_sb,
+ .kill_sb = generic_shutdown_super,
+ .fs_flags = FS_REVAL_DOT,
+};
+
+static int __init init_unionfs_fs(void)
+{
+ int err;
+
+ pr_info("Registering unionfs " UNIONFS_VERSION "\n");
+
+ err = unionfs_init_filldir_cache();
+ if (unlikely(err))
+ goto out;
+ err = unionfs_init_inode_cache();
+ if (unlikely(err))
+ goto out;
+ err = unionfs_init_dentry_cache();
+ if (unlikely(err))
+ goto out;
+ err = init_sioq();
+ if (unlikely(err))
+ goto out;
+ err = register_filesystem(&unionfs_fs_type);
+out:
+ if (unlikely(err)) {
+ stop_sioq();
+ unionfs_destroy_filldir_cache();
+ unionfs_destroy_inode_cache();
+ unionfs_destroy_dentry_cache();
+ }
+ return err;
+}
+
+static void __exit exit_unionfs_fs(void)
+{
+ stop_sioq();
+ unionfs_destroy_filldir_cache();
+ unionfs_destroy_inode_cache();
+ unionfs_destroy_dentry_cache();
+ unregister_filesystem(&unionfs_fs_type);
+ pr_info("Completed unionfs module unload\n");
+}
+
+MODULE_AUTHOR("Erez Zadok, Filesystems and Storage Lab, Stony Brook University"
+ " (http://www.fsl.cs.sunysb.edu)");
+MODULE_DESCRIPTION("Unionfs " UNIONFS_VERSION
+ " (http://unionfs.filesystems.org)");
+MODULE_LICENSE("GPL");
+
+module_init(init_unionfs_fs);
+module_exit(exit_unionfs_fs);
diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
new file mode 100644
index 0000000..eb6b40a
--- /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;
+ 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..88d07e4
--- /dev/null
+++ b/fs/unionfs/rename.c
@@ -0,0 +1,520 @@
+/*
+ * 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);
+
+ /* see Documentation/filesystems/unionfs/issues.txt */
+ lockdep_off();
+ trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+ /* source should not be ancenstor of target */
+ if (trap == lower_old_dentry) {
+ err = -EINVAL;
+ goto out_err_unlock;
+ }
+ /* target should not be ancenstor of source */
+ if (trap == lower_new_dentry) {
+ err = -ENOTEMPTY;
+ goto out_err_unlock;
+ }
+ err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
+ lower_new_dir_dentry->d_inode, lower_new_dentry);
+out_err_unlock:
+ if (!err) {
+ /* update parent dir times */
+ fsstack_copy_attr_times(old_dir, lower_old_dir_dentry->d_inode);
+ fsstack_copy_attr_times(new_dir, lower_new_dir_dentry->d_inode);
+ }
+ unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+ lockdep_on();
+
+ dput(lower_old_dir_dentry);
+ dput(lower_new_dir_dentry);
+ dput(lower_old_dentry);
+ dput(lower_new_dentry);
+
+out:
+ if (!err) {
+ /* Fixup the new_dentry. */
+ if (bindex < dbstart(new_dentry))
+ dbstart(new_dentry) = bindex;
+ else if (bindex > dbend(new_dentry))
+ dbend(new_dentry) = bindex;
+ }
+
+ return err;
+}
+
+/*
+ * Main rename code. This is sufficiently complex, that it's documented in
+ * Documentation/filesystems/unionfs/rename.txt. This routine calls
+ * __unionfs_rename() above to perform some of the work.
+ */
+static int do_unionfs_rename(struct inode *old_dir,
+ struct dentry *old_dentry,
+ struct 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..64d0cc0
--- /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, s->mode);
+ 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..9cf560d
--- /dev/null
+++ b/fs/unionfs/sioq.h
@@ -0,0 +1,92 @@
+/*
+ * 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;
+ umode_t mode;
+};
+
+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..1312a49
--- /dev/null
+++ b/fs/unionfs/super.c
@@ -0,0 +1,1048 @@
+/*
+ * 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;
+
+static void unionfs_read_inode(struct inode *inode)
+{
+ int size;
+ struct unionfs_inode_info *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");
+ BUG();
+ }
+
+ 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;
+
+}
+
+/*
+ * we now define delete_inode, because there are two VFS paths that may
+ * destroy an inode: one of them calls clear inode before doing everything
+ * else that's needed, and the other is fine. This way we truncate the inode
+ * size (and its pages) and then clear our own inode, which will do an iput
+ * on our and the lower inode.
+ *
+ * No need to lock sb info's rwsem.
+ */
+static void unionfs_delete_inode(struct inode *inode)
+{
+#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
+ spin_lock(&inode->i_lock);
+#endif
+ i_size_write(inode, 0); /* every f/s seems to do that */
+#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
+ spin_unlock(&inode->i_lock);
+#endif
+
+ if (inode->i_data.nrpages)
+ truncate_inode_pages(&inode->i_data, 0);
+
+ clear_inode(inode);
+}
+
+/*
+ * final actions when unmounting a file system
+ *
+ * No need to lock rwsem.
+ */
+static void unionfs_put_super(struct super_block *sb)
+{
+ int bindex, bstart, bend;
+ struct unionfs_sb_info *spd;
+ int leaks = 0;
+
+ spd = UNIONFS_SB(sb);
+ if (!spd)
+ return;
+
+ bstart = sbstart(sb);
+ bend = sbend(sb);
+
+ /* Make sure we have no leaks of branchget/branchput. */
+ for (bindex = bstart; bindex <= bend; bindex++)
+ if (unlikely(branch_count(sb, bindex) != 0)) {
+ printk(KERN_CRIT
+ "unionfs: branch %d has %d references left!\n",
+ bindex, branch_count(sb, bindex));
+ leaks = 1;
+ }
+ 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;
+ 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);
+ err = vfs_statfs(lower_dentry, buf);
+
+ /* set return buf to our f/s to avoid confusing user-level utils */
+ buf->f_type = UNIONFS_SUPER_MAGIC;
+ /*
+ * Our maximum file name can is shorter by a few bytes because every
+ * file name could potentially be whited-out.
+ *
+ * XXX: this restriction goes away with ODF.
+ */
+ unionfs_set_max_namelen(&buf->f_namelen);
+
+ /*
+ * reset two fields to avoid confusing user-land.
+ * XXX: is this still necessary?
+ */
+ memset(&buf->f_fsid, 0, sizeof(__kernel_fsid_t));
+ memset(&buf->f_spare, 0, sizeof(buf->f_spare));
+
+out:
+ unionfs_check_dentry(dentry);
+ unionfs_unlock_dentry(dentry);
+ unionfs_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.mnt == new_lower_paths[idx].mnt &&
+ nd.dentry == new_lower_paths[idx].dentry)
+ break;
+ path_release(&nd); /* 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.mnt == new_lower_paths[idx].mnt &&
+ nd.dentry == new_lower_paths[idx].dentry)
+ break;
+ path_release(&nd); /* 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.
+ */
+ pathput(&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.mnt == new_lower_paths[idx].mnt &&
+ nd.dentry == new_lower_paths[idx].dentry)
+ break;
+ path_release(&nd); /* 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_release(&nd);
+ 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.dentry;
+ new_lower_paths[idx].mnt = nd.mnt;
+
+ new_data[idx].sb = nd.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++)
+ pathget(&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++)
+ pathput(&tmp_lower_paths[i]);
+out_free:
+ kfree(tmp_lower_paths);
+ kfree(tmp_data);
+ kfree(new_lower_paths);
+ kfree(new_data);
+ kfree(new_lower_inodes);
+out_error:
+ unionfs_check_dentry(sb->s_root);
+ unionfs_write_unlock(sb);
+ return err;
+}
+
+/*
+ * Called by iput() when the inode reference count reached zero
+ * and the inode is not hashed anywhere. Used to clear anything
+ * that needs to be, before the inode is completely destroyed and put
+ * on the inode free list.
+ *
+ * No need to lock sb info's rwsem.
+ */
+static void unionfs_clear_inode(struct inode *inode)
+{
+ int bindex, bstart, bend;
+ struct inode *lower_inode;
+ struct list_head *pos, *n;
+ struct unionfs_dir_state *rdstate;
+
+ list_for_each_safe(pos, n, &UNIONFS_I(inode)->readdircache) {
+ rdstate = list_entry(pos, struct unionfs_dir_state, cache);
+ list_del(&rdstate->cache);
+ free_rdstate(rdstate);
+ }
+
+ /*
+ * Decrement a reference to a lower_inode, which was incremented
+ * by our read_inode when it was created initially.
+ */
+ bstart = ibstart(inode);
+ bend = ibend(inode);
+ if (bstart >= 0) {
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
+ if (!lower_inode)
+ continue;
+ unionfs_set_lower_inode_idx(inode, bindex, NULL);
+ /* see Documentation/filesystems/unionfs/issues.txt */
+ lockdep_off();
+ iput(lower_inode);
+ lockdep_on();
+ }
+ }
+
+ kfree(UNIONFS_I(inode)->lower_inodes);
+ UNIONFS_I(inode)->lower_inodes = NULL;
+}
+
+static struct inode *unionfs_alloc_inode(struct super_block *sb)
+{
+ struct unionfs_inode_info *i;
+
+ i = kmem_cache_alloc(unionfs_inode_cachep, GFP_KERNEL);
+ if (unlikely(!i))
+ return NULL;
+
+ /* memset everything up to the inode to 0 */
+ memset(i, 0, offsetof(struct unionfs_inode_info, vfs_inode));
+
+ i->vfs_inode.i_version = 1;
+ return &i->vfs_inode;
+}
+
+static void unionfs_destroy_inode(struct inode *inode)
+{
+ kmem_cache_free(unionfs_inode_cachep, UNIONFS_I(inode));
+}
+
+/* unionfs inode cache constructor */
+static void init_once(void *v, struct kmem_cache *cachep, unsigned long flags)
+{
+ struct unionfs_inode_info *i = v;
+
+ inode_init_once(&i->vfs_inode);
+}
+
+int unionfs_init_inode_cache(void)
+{
+ int err = 0;
+
+ unionfs_inode_cachep =
+ kmem_cache_create("unionfs_inode_cache",
+ sizeof(struct unionfs_inode_info), 0,
+ SLAB_RECLAIM_ACCOUNT, init_once);
+ if (unlikely(!unionfs_inode_cachep))
+ err = -ENOMEM;
+ return err;
+}
+
+/* unionfs inode cache destructor */
+void unionfs_destroy_inode_cache(void)
+{
+ if (unionfs_inode_cachep)
+ kmem_cache_destroy(unionfs_inode_cachep);
+}
+
+/*
+ * Called when we have a dirty inode, right here we only throw out
+ * parts of our readdir list that are too old.
+ *
+ * No need to grab sb info's rwsem.
+ */
+static int unionfs_write_inode(struct inode *inode, int sync)
+{
+ struct list_head *pos, *n;
+ struct unionfs_dir_state *rdstate;
+
+ spin_lock(&UNIONFS_I(inode)->rdlock);
+ list_for_each_safe(pos, n, &UNIONFS_I(inode)->readdircache) {
+ rdstate = list_entry(pos, struct unionfs_dir_state, cache);
+ /* We keep this list in LRU order. */
+ if ((rdstate->access + RDCACHE_JIFFIES) > jiffies)
+ break;
+ UNIONFS_I(inode)->rdcount--;
+ list_del(&rdstate->cache);
+ free_rdstate(rdstate);
+ }
+ spin_unlock(&UNIONFS_I(inode)->rdlock);
+
+ return 0;
+}
+
+/*
+ * Used only in nfs, to kill any pending RPC tasks, so that subsequent
+ * code can actually succeed and won't leave tasks that need handling.
+ */
+static void unionfs_umount_begin(struct vfsmount *mnt, int flags)
+{
+ struct super_block *sb, *lower_sb;
+ struct vfsmount *lower_mnt;
+ int bindex, bstart, bend;
+
+ if (!(flags & MNT_FORCE))
+ /*
+ * we are not being MNT_FORCE'd, therefore we should emulate
+ * old behavior
+ */
+ return;
+
+ sb = mnt->mnt_sb;
+
+ unionfs_read_lock(sb, UNIONFS_SMUTEX_CHILD);
+
+ bstart = sbstart(sb);
+ bend = sbend(sb);
+ for (bindex = bstart; bindex <= bend; bindex++) {
+ lower_mnt = unionfs_lower_mnt_idx(sb->s_root, bindex);
+ lower_sb = unionfs_lower_super_idx(sb, bindex);
+
+ if (lower_mnt && lower_sb && lower_sb->s_op &&
+ lower_sb->s_op->umount_begin)
+ lower_sb->s_op->umount_begin(lower_mnt, flags);
+ }
+
+ 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++) {
+ path = d_path(unionfs_lower_dentry_idx(sb->s_root, bindex),
+ unionfs_lower_mnt_idx(sb->s_root, bindex),
+ 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 = {
+ .read_inode = unionfs_read_inode,
+ .delete_inode = unionfs_delete_inode,
+ .put_super = unionfs_put_super,
+ .statfs = unionfs_statfs,
+ .remount_fs = unionfs_remount_fs,
+ .clear_inode = unionfs_clear_inode,
+ .umount_begin = unionfs_umount_begin,
+ .show_options = unionfs_show_options,
+ .write_inode = unionfs_write_inode,
+ .alloc_inode = unionfs_alloc_inode,
+ .destroy_inode = unionfs_destroy_inode,
+};
diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
new file mode 100644
index 0000000..f6d19ed
--- /dev/null
+++ b/fs/unionfs/union.h
@@ -0,0 +1,662 @@
+/*
+ * 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 */
+
+#ifndef noinline_for_stack
+# define noinline_for_stack noinline
+#endif /* not noinline_for_stack */
+
+/* file private data. */
+struct unionfs_file_info {
+ int bstart;
+ int bend;
+ atomic_t generation;
+
+ struct unionfs_dir_state *rdstate;
+ struct file **lower_files;
+ int *saved_branch_ids; /* IDs of branches when file was opened */
+ struct vm_operations_struct *lower_vm_ops;
+ bool wrote_to_file; /* for delayed copyup */
+};
+
+/* unionfs inode data in memory */
+struct unionfs_inode_info {
+ int bstart;
+ int bend;
+ atomic_t generation;
+ /* Stuff for readdir over NFS. */
+ spinlock_t rdlock;
+ struct list_head readdircache;
+ int rdcount;
+ int hashsize;
+ int cookie;
+
+ /* The lower inodes */
+ struct inode **lower_inodes;
+
+ struct inode vfs_inode;
+};
+
+/* unionfs dentry data in memory */
+struct unionfs_dentry_info {
+ /*
+ * The semaphore is used to lock the dentry as soon as we get into a
+ * unionfs function from the VFS. Our lock ordering is that children
+ * go before their parents.
+ */
+ struct mutex lock;
+ int bstart;
+ int bend;
+ int bopaque;
+ int bcount;
+ atomic_t generation;
+ struct path *lower_paths;
+};
+
+/* These are the pointers to our various objects. */
+struct unionfs_data {
+ struct super_block *sb; /* lower super_block */
+ atomic_t open_files; /* number of open files on branch */
+ int branchperms;
+ int branch_id; /* unique branch ID at re/mount time */
+};
+
+/* unionfs super-block data in memory */
+struct unionfs_sb_info {
+ int bend;
+
+ atomic_t generation;
+
+ /*
+ * This rwsem is used to make sure that a branch management
+ * operation...
+ * 1) will not begin before all currently in-flight operations
+ * complete.
+ * 2) any new operations do not execute until the currently
+ * running branch management operation completes.
+ *
+ * The write_lock_owner records the PID of the task which grabbed
+ * the rw_sem for writing. If the same task also tries to grab the
+ * read lock, we allow it. This prevents a self-deadlock when
+ * branch-management is used on a pivot_root'ed union, because we
+ * have to ->lookup paths which belong to the same union.
+ */
+ struct unionfs_rw_semaphore rwsem;
+ pid_t write_lock_owner; /* PID of rw_sem owner (write lock) */
+ int high_branch_id; /* last unique branch ID given */
+ char *dev_name; /* to identify different unions in pr_debug */
+ struct unionfs_data *data;
+};
+
+/*
+ * structure for making the linked list of entries by readdir on left branch
+ * to compare with entries on right branch
+ */
+struct filldir_node {
+ struct list_head file_list; /* list for directory entries */
+ char *name; /* name entry */
+ int hash; /* name hash */
+ int namelen; /* name len since name is not 0 terminated */
+
+ /*
+ * we can check for duplicate whiteouts and files in the same branch
+ * in order to return -EIO.
+ */
+ int bindex;
+
+ /* is this a whiteout entry? */
+ int whiteout;
+
+ /* Inline name, so we don't need to separately kmalloc small ones */
+ char iname[DNAME_INLINE_LEN_MIN];
+};
+
+/* Directory hash table. */
+struct unionfs_dir_state {
+ unsigned int cookie; /* the cookie, based off of rdversion */
+ unsigned int offset; /* The entry we have returned. */
+ int bindex;
+ loff_t dirpos; /* offset within the lower level directory */
+ int size; /* How big is the hash table? */
+ int hashentries; /* How many entries have been inserted? */
+ unsigned long access;
+
+ /* This cache list is used when the inode keeps us around. */
+ struct list_head cache;
+ struct list_head list[0];
+};
+
+/* externs needed for fanout.h or sioq.h */
+extern int unionfs_get_nlinks(const struct inode *inode);
+extern void unionfs_copy_attr_times(struct inode *upper);
+extern void unionfs_copy_attr_all(struct inode *dest, const struct inode *src);
+
+/* include miscellaneous macros */
+#include "fanout.h"
+#include "sioq.h"
+
+/* externs for cache creation/deletion routines */
+extern void unionfs_destroy_filldir_cache(void);
+extern int unionfs_init_filldir_cache(void);
+extern int unionfs_init_inode_cache(void);
+extern void unionfs_destroy_inode_cache(void);
+extern int unionfs_init_dentry_cache(void);
+extern void unionfs_destroy_dentry_cache(void);
+
+/* Initialize and free readdir-specific state. */
+extern int init_rdstate(struct file *file);
+extern struct unionfs_dir_state *alloc_rdstate(struct inode *inode,
+ int bindex);
+extern struct unionfs_dir_state *find_rdstate(struct inode *inode,
+ loff_t fpos);
+extern void free_rdstate(struct unionfs_dir_state *state);
+extern int add_filldir_node(struct unionfs_dir_state *rdstate,
+ const char *name, int namelen, int bindex,
+ int whiteout);
+extern struct filldir_node *find_filldir_node(struct unionfs_dir_state *rdstate,
+ const char *name, int namelen,
+ int is_whiteout);
+
+extern struct dentry **alloc_new_dentries(int objs);
+extern struct unionfs_data *alloc_new_data(int objs);
+
+/* We can only use 32-bits of offset for rdstate --- blech! */
+#define DIREOF (0xfffff)
+#define RDOFFBITS 20 /* This is the number of bits in DIREOF. */
+#define MAXRDCOOKIE (0xfff)
+/* Turn an rdstate into an offset. */
+static inline off_t rdstate2offset(struct unionfs_dir_state *buf)
+{
+ off_t tmp;
+
+ tmp = ((buf->cookie & MAXRDCOOKIE) << RDOFFBITS)
+ | (buf->offset & DIREOF);
+ return tmp;
+}
+
+/* Macros for locking a super_block. */
+enum unionfs_super_lock_class {
+ UNIONFS_SMUTEX_NORMAL,
+ UNIONFS_SMUTEX_PARENT, /* when locking on behalf of file */
+ UNIONFS_SMUTEX_CHILD, /* when locking on behalf of dentry */
+};
+static inline void unionfs_read_lock(struct super_block *sb, int subclass)
+{
+ if (UNIONFS_SB(sb)->write_lock_owner &&
+ UNIONFS_SB(sb)->write_lock_owner == current->pid)
+ return;
+ down_read_nested(&UNIONFS_SB(sb)->rwsem, subclass);
+}
+static inline void unionfs_read_unlock(struct super_block *sb)
+{
+ if (UNIONFS_SB(sb)->write_lock_owner &&
+ UNIONFS_SB(sb)->write_lock_owner == current->pid)
+ return;
+ up_read(&UNIONFS_SB(sb)->rwsem);
+}
+static inline void unionfs_write_lock(struct super_block *sb)
+{
+ down_write(&UNIONFS_SB(sb)->rwsem);
+ UNIONFS_SB(sb)->write_lock_owner = current->pid;
+}
+static inline void unionfs_write_unlock(struct super_block *sb)
+{
+ up_write(&UNIONFS_SB(sb)->rwsem);
+ UNIONFS_SB(sb)->write_lock_owner = 0;
+}
+
+static inline void unionfs_double_lock_dentry(struct dentry *d1,
+ struct dentry *d2)
+{
+ BUG_ON(d1 == d2);
+ if (d1 < d2) {
+ unionfs_lock_dentry(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, struct dentry *dentry,
+ int datasync);
+extern int unionfs_fasync(int fd, struct file *file, int flag);
+
+/* Inode operations */
+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);
+}
+
+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..2edb6ca
--- /dev/null
+++ b/fs/unionfs/unlink.c
@@ -0,0 +1,282 @@
+/*
+ * 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) {
+ /* see Documentation/filesystems/unionfs/issues.txt */
+ lockdep_off();
+ err = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
+ lockdep_on();
+ }
+ dput(lower_dentry);
+
+ fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
+ /* propagate number of hard-links */
+ dentry->d_inode->i_nlink = unionfs_get_nlinks(dentry->d_inode);
+
+out:
+ if (lower_dir_dentry)
+ unlock_dir(lower_dir_dentry);
+ return err;
+}
+
+int unionfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ int err = 0;
+ struct unionfs_dir_state *namelist = NULL;
+ 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..fa5ab93
--- /dev/null
+++ b/fs/unionfs/whiteout.c
@@ -0,0 +1,577 @@
+/*
+ * 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_one_len(whname, lower_parent, strlen(whname));
+ if (IS_ERR(wh_dentry)) {
+ err = PTR_ERR(wh_dentry);
+ goto out;
+ }
+
+ /* check if negative dentry (ENOENT) */
+ if (!wh_dentry->d_inode)
+ goto out;
+
+ /* whiteout found: check if valid type */
+ if (!S_ISREG(wh_dentry->d_inode->i_mode)) {
+ printk(KERN_ERR "unionfs: invalid whiteout %s entry type %d\n",
+ whname, wh_dentry->d_inode->i_mode);
+ dput(wh_dentry);
+ err = -EIO;
+ goto out;
+ }
+
+out:
+ kfree(whname);
+ if (err)
+ wh_dentry = ERR_PTR(err);
+ return wh_dentry;
+}
+
+/* find and return first whiteout in parent directory, else ENOENT */
+struct dentry *find_first_whiteout(struct dentry *dentry)
+{
+ int bindex, bstart, bend;
+ struct dentry *parent, *lower_parent, *wh_dentry;
+
+ parent = dget_parent(dentry);
+
+ 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_one_len(name, lower_dentry->d_parent,
+ dentry->d_name.len + UNIONFS_WHLEN);
+ if (IS_ERR(lower_wh_dentry))
+ continue;
+
+ /*
+ * The whiteout already exists. This used to be impossible,
+ * but now is possible because of opaqueness.
+ */
+ if (lower_wh_dentry->d_inode) {
+ dput(lower_wh_dentry);
+ err = 0;
+ goto out;
+ }
+
+ err = init_lower_nd(&nd, LOOKUP_CREATE);
+ if (unlikely(err < 0))
+ goto out;
+ lower_dir_dentry = lock_parent_wh(lower_wh_dentry);
+ err = is_robranch_super(dentry->d_sb, bindex);
+ if (!err)
+ err = vfs_create(lower_dir_dentry->d_inode,
+ lower_wh_dentry,
+ ~current->fs->umask & S_IRUGO,
+ &nd);
+ unlock_dir(lower_dir_dentry);
+ dput(lower_wh_dentry);
+ release_lower_nd(&nd, err);
+
+ if (!err || !IS_COPYUP_ERR(err))
+ break;
+ }
+
+ /* set dbopaque so that lookup will not proceed after this branch */
+ if (!err)
+ dbopaque(dentry) = bindex;
+
+out:
+ kfree(name);
+ return err;
+}
+
+/*
+ * Delete all of the whiteouts in a given directory for rmdir.
+ *
+ * lower directory inode should be locked
+ */
+static int do_delete_whiteouts(struct dentry *dentry, int bindex,
+ struct unionfs_dir_state *namelist)
+{
+ int err = 0;
+ struct dentry *lower_dir_dentry = NULL;
+ struct dentry *lower_dentry;
+ char *name = NULL, *p;
+ struct inode *lower_dir;
+ int i;
+ struct list_head *pos;
+ struct filldir_node *cursor;
+
+ /* Find out lower parent dentry */
+ lower_dir_dentry = unionfs_lower_dentry_idx(dentry, bindex);
+ BUG_ON(!S_ISDIR(lower_dir_dentry->d_inode->i_mode));
+ lower_dir = lower_dir_dentry->d_inode;
+ BUG_ON(!S_ISDIR(lower_dir->i_mode));
+
+ err = -ENOMEM;
+ name = __getname();
+ if (unlikely(!name))
+ goto out;
+ strcpy(name, UNIONFS_WHPFX);
+ p = name + UNIONFS_WHLEN;
+
+ err = 0;
+ for (i = 0; !err && i < namelist->size; i++) {
+ list_for_each(pos, &namelist->list[i]) {
+ cursor =
+ list_entry(pos, struct filldir_node,
+ file_list);
+ /* Only operate on whiteouts in this branch. */
+ if (cursor->bindex != bindex)
+ continue;
+ if (!cursor->whiteout)
+ continue;
+
+ strlcpy(p, cursor->name, PATH_MAX - UNIONFS_WHLEN);
+ lower_dentry =
+ lookup_one_len(name, lower_dir_dentry,
+ cursor->namelen +
+ UNIONFS_WHLEN);
+ if (IS_ERR(lower_dentry)) {
+ err = PTR_ERR(lower_dentry);
+ break;
+ }
+ if (lower_dentry->d_inode)
+ err = vfs_unlink(lower_dir, lower_dentry);
+ dput(lower_dentry);
+ if (err)
+ break;
+ }
+ }
+
+ __putname(name);
+
+ /* After all of the removals, we should copy the attributes once. */
+ fsstack_copy_attr_times(dentry->d_inode, lower_dir_dentry->d_inode);
+
+out:
+ return err;
+}
+
+
+void __delete_whiteouts(struct work_struct *work)
+{
+ struct sioq_args *args = container_of(work, struct sioq_args, work);
+ struct deletewh_args *d = &args->deletewh;
+
+ args->err = do_delete_whiteouts(d->dentry, d->bindex, d->namelist);
+ complete(&args->comp);
+}
+
+/* delete whiteouts in a dir (for rmdir operation) using sioq if necessary */
+int delete_whiteouts(struct dentry *dentry, int bindex,
+ struct unionfs_dir_state *namelist)
+{
+ int err;
+ struct super_block *sb;
+ struct dentry *lower_dir_dentry;
+ struct inode *lower_dir;
+ struct sioq_args args;
+
+ sb = dentry->d_sb;
+
+ BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));
+ BUG_ON(bindex < dbstart(dentry));
+ BUG_ON(bindex > dbend(dentry));
+ err = is_robranch_super(sb, bindex);
+ if (err)
+ goto out;
+
+ lower_dir_dentry = unionfs_lower_dentry_idx(dentry, bindex);
+ BUG_ON(!S_ISDIR(lower_dir_dentry->d_inode->i_mode));
+ lower_dir = lower_dir_dentry->d_inode;
+ BUG_ON(!S_ISDIR(lower_dir->i_mode));
+
+ if (!permission(lower_dir, MAY_WRITE | MAY_EXEC, NULL)) {
+ 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 (!permission(lower_inode, MAY_EXEC, NULL)) {
+ wh_lower_dentry =
+ lookup_one_len(UNIONFS_DIR_OPAQUE, lower_dentry,
+ sizeof(UNIONFS_DIR_OPAQUE) - 1);
+ } else {
+ args.is_opaque.dentry = lower_dentry;
+ run_sioq(__is_opaque_dir, &args);
+ wh_lower_dentry = args.ret;
+ }
+
+ mutex_unlock(&lower_inode->i_mutex);
+
+ if (IS_ERR(wh_lower_dentry)) {
+ err = PTR_ERR(wh_lower_dentry);
+ goto out;
+ }
+
+ /* This is an opaque dir iff wh_lower_dentry is positive */
+ err = !!wh_lower_dentry->d_inode;
+
+ dput(wh_lower_dentry);
+out:
+ return err;
+}
+
+void __is_opaque_dir(struct work_struct *work)
+{
+ struct sioq_args *args = container_of(work, struct sioq_args, work);
+
+ args->ret = lookup_one_len(UNIONFS_DIR_OPAQUE, args->is_opaque.dentry,
+ sizeof(UNIONFS_DIR_OPAQUE) - 1);
+ complete(&args->comp);
+}
+
+int make_dir_opaque(struct dentry *dentry, int bindex)
+{
+ int err = 0;
+ struct dentry *lower_dentry, *diropq;
+ struct inode *lower_dir;
+ struct nameidata nd;
+ kernel_cap_t orig_cap;
+
+ /*
+ * Opaque directory whiteout markers are special files (like regular
+ * whiteouts), and should appear to the users as if they don't
+ * exist. They should be created/deleted regardless of directory
+ * search/create permissions, but only for the duration of this
+ * creation of the .wh.__dir_opaque: file. Note, this does not
+ * circumvent normal ->permission).
+ */
+ orig_cap = current->cap_effective;
+ cap_raise(current->cap_effective, CAP_DAC_READ_SEARCH);
+ cap_raise(current->cap_effective, CAP_DAC_OVERRIDE);
+
+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
+ lower_dir = lower_dentry->d_inode;
+ BUG_ON(!S_ISDIR(dentry->d_inode->i_mode) ||
+ !S_ISDIR(lower_dir->i_mode));
+
+ mutex_lock(&lower_dir->i_mutex);
+ diropq = lookup_one_len(UNIONFS_DIR_OPAQUE, lower_dentry,
+ sizeof(UNIONFS_DIR_OPAQUE) - 1);
+ if (IS_ERR(diropq)) {
+ err = PTR_ERR(diropq);
+ goto out;
+ }
+
+ err = init_lower_nd(&nd, LOOKUP_CREATE);
+ if (unlikely(err < 0))
+ goto out;
+ if (!diropq->d_inode)
+ err = vfs_create(lower_dir, diropq, S_IRUGO, &nd);
+ if (!err)
+ dbopaque(dentry) = bindex;
+ release_lower_nd(&nd, err);
+
+ dput(diropq);
+
+out:
+ mutex_unlock(&lower_dir->i_mutex);
+ current->cap_effective = orig_cap;
+ return err;
+}
diff --git a/fs/unionfs/xattr.c b/fs/unionfs/xattr.c
new file mode 100644
index 0000000..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 bb516ce..64f1ced 100644
--- a/include/linux/fs_stack.h
+++ b/include/linux/fs_stack.h
@@ -1,17 +1,27 @@
+/*
+ * 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.
*/
#include <linux/fs.h>
/* externs for fs/stack.c */
-extern void fsstack_copy_attr_all(struct inode *dest, const struct inode *src,
- int (*get_nlinks)(struct inode *));
-
-extern void fsstack_copy_inode_size(struct inode *dst, const struct inode *src);
+extern void fsstack_copy_attr_all(struct inode *dest, const struct inode *src);
+extern void fsstack_copy_inode_size(struct inode *dst, struct inode *src);
/* inlines */
static inline void fsstack_copy_attr_atime(struct inode *dest,
diff --git a/include/linux/magic.h b/include/linux/magic.h
index 36cc20d..8dac50b 100644
--- a/include/linux/magic.h
+++ b/include/linux/magic.h
@@ -35,6 +35,8 @@
#define REISER2FS_SUPER_MAGIC_STRING "ReIsEr2Fs"
#define REISER2FS_JR_SUPER_MAGIC_STRING "ReIsEr3Fs"
+#define UNIONFS_SUPER_MAGIC 0xf15f083d
+
#define SMB_SUPER_MAGIC 0x517B
#define USBDEVICE_SUPER_MAGIC 0x9fa2
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 6c38efb..e9477b5 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -3,6 +3,7 @@
#include <linux/dcache.h>
#include <linux/linkage.h>
+#include <linux/mount.h>
struct vfsmount;
@@ -100,4 +101,16 @@ static inline char *nd_get_link(struct nameidata *nd)
return nd->saved_names[nd->depth];
}
+static inline void pathget(struct path *path)
+{
+ mntget(path->mnt);
+ dget(path->dentry);
+}
+
+static inline void pathput(struct path *path)
+{
+ dput(path->dentry);
+ mntput(path->mnt);
+}
+
#endif /* _LINUX_NAMEI_H */
diff --git a/include/linux/splice.h b/include/linux/splice.h
index 33e447f..616d473 100644
--- a/include/linux/splice.h
+++ b/include/linux/splice.h
@@ -69,5 +69,10 @@ extern ssize_t splice_to_pipe(struct pipe_inode_info *,
struct splice_pipe_desc *);
extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
splice_direct_actor *);
+extern long vfs_splice_from(struct pipe_inode_info *pipe, struct file *out,
+ loff_t *ppos, size_t len, unsigned int flags);
+extern long vfs_splice_to(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags);
#endif
diff --git a/include/linux/union_fs.h b/include/linux/union_fs.h
new file mode 100644
index 0000000..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 */
+