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path: root/fs/overlayfs/super.c
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2018-08-03ovl: Sync upper dirty data when syncing overlayfsChengguang Xu
commit e8d4bfe3a71537284a90561f77c85dea6c154369 upstream. When executing filesystem sync or umount on overlayfs, dirty data does not get synced as expected on upper filesystem. This patch fixes sync filesystem method to keep data consistency for overlayfs. Signed-off-by: Chengguang Xu <cgxu@mykernel.net> Fixes: e593b2bf513d ("ovl: properly implement sync_filesystem()") Cc: <stable@vger.kernel.org> #4.11 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-22ovl: hash directory inodes for fsnotifyAmir Goldstein
commit 31747eda41ef3c30c09c5c096b380bf54013746a upstream. fsnotify pins a watched directory inode in cache, but if directory dentry is released, new lookup will allocate a new dentry and a new inode. Directory events will be notified on the new inode, while fsnotify listener is watching the old pinned inode. Hash all directory inodes to reuse the pinned inode on lookup. Pure upper dirs are hashes by real upper inode, merge and lower dirs are hashed by real lower inode. The reference to lower inode was being held by the lower dentry object in the overlay dentry (oe->lowerstack[0]). Releasing the overlay dentry may drop lower inode refcount to zero. Add a refcount on behalf of the overlay inode to prevent that. As a by-product, hashing directory inodes also detects multiple redirected dirs to the same lower dir and uncovered redirected dir target on and returns -ESTALE on lookup. The reported issue dates back to initial version of overlayfs, but this patch depends on ovl_inode code that was introduced in kernel v4.13. Cc: <stable@vger.kernel.org> #v4.13 Reported-by: Niklas Cassel <niklas.cassel@axis.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Tested-by: Niklas Cassel <niklas.cassel@axis.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-19ovl: add NULL check in ovl_alloc_inodeHirofumi Nakagawa
This was detected by fault injection test Signed-off-by: Hirofumi Nakagawa <nklabs@gmail.com> Fixes: 13cf199d0088 ("ovl: allocate an ovl_inode struct") Cc: <stable@vger.kernel.org> # v4.13
2017-10-05ovl: fix regression caused by exclusive upper/work dir protectionAmir Goldstein
Enforcing exclusive ownership on upper/work dirs caused a docker regression: https://github.com/moby/moby/issues/34672. Euan spotted the regression and pointed to the offending commit. Vivek has brought the regression to my attention and provided this reproducer: Terminal 1: mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none merged/ Terminal 2: unshare -m Terminal 1: umount merged mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none merged/ mount: /root/overlay-testing/merged: none already mounted or mount point busy To fix the regression, I replaced the error with an alarming warning. With index feature enabled, mount does fail, but logs a suggestion to override exclusive dir protection by disabling index. Note that index=off mount does take the inuse locks, so a concurrent index=off will issue the warning and a concurrent index=on mount will fail. Documentation was updated to reflect this change. Fixes: 2cac0c00a6cd ("ovl: get exclusive ownership on upper/work dirs") Cc: <stable@vger.kernel.org> # v4.13 Reported-by: Euan Kemp <euank@euank.com> Reported-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-09-14Merge branch 'work.mount' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull mount flag updates from Al Viro: "Another chunk of fmount preparations from dhowells; only trivial conflicts for that part. It separates MS_... bits (very grotty mount(2) ABI) from the struct super_block ->s_flags (kernel-internal, only a small subset of MS_... stuff). This does *not* convert the filesystems to new constants; only the infrastructure is done here. The next step in that series is where the conflicts would be; that's the conversion of filesystems. It's purely mechanical and it's better done after the merge, so if you could run something like list=$(for i in MS_RDONLY MS_NOSUID MS_NODEV MS_NOEXEC MS_SYNCHRONOUS MS_MANDLOCK MS_DIRSYNC MS_NOATIME MS_NODIRATIME MS_SILENT MS_POSIXACL MS_KERNMOUNT MS_I_VERSION MS_LAZYTIME; do git grep -l $i fs drivers/staging/lustre drivers/mtd ipc mm include/linux; done|sort|uniq|grep -v '^fs/namespace.c$') sed -i -e 's/\<MS_RDONLY\>/SB_RDONLY/g' \ -e 's/\<MS_NOSUID\>/SB_NOSUID/g' \ -e 's/\<MS_NODEV\>/SB_NODEV/g' \ -e 's/\<MS_NOEXEC\>/SB_NOEXEC/g' \ -e 's/\<MS_SYNCHRONOUS\>/SB_SYNCHRONOUS/g' \ -e 's/\<MS_MANDLOCK\>/SB_MANDLOCK/g' \ -e 's/\<MS_DIRSYNC\>/SB_DIRSYNC/g' \ -e 's/\<MS_NOATIME\>/SB_NOATIME/g' \ -e 's/\<MS_NODIRATIME\>/SB_NODIRATIME/g' \ -e 's/\<MS_SILENT\>/SB_SILENT/g' \ -e 's/\<MS_POSIXACL\>/SB_POSIXACL/g' \ -e 's/\<MS_KERNMOUNT\>/SB_KERNMOUNT/g' \ -e 's/\<MS_I_VERSION\>/SB_I_VERSION/g' \ -e 's/\<MS_LAZYTIME\>/SB_LAZYTIME/g' \ $list and commit it with something along the lines of 'convert filesystems away from use of MS_... constants' as commit message, it would save a quite a bit of headache next cycle" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: VFS: Differentiate mount flags (MS_*) from internal superblock flags VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb) vfs: Add sb_rdonly(sb) to query the MS_RDONLY flag on s_flags
2017-09-05ovl: fix relatime for directoriesMiklos Szeredi
Need to treat non-regular overlayfs files the same as regular files when checking for an atime update. Add a d_real() flag to make it return the upper dentry for all file types. Reported-by: "zhangyi (F)" <yi.zhang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-09-04vfs: add flags to d_real()Miklos Szeredi
Add a separate flags argument (in addition to the open flags) to control the behavior of d_real(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-09-04ovl: cleanup d_real for negativeMiklos Szeredi
d_real() is never called with a negative dentry. So remove the d_is_negative() check (which would never trigger anyway, since d_is_reg() returns false for a negative dentry). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-27ovl: constant d_ino for non-merge dirsMiklos Szeredi
Impure directories are ones which contain objects with origins (i.e. those that have been copied up). These are relevant to readdir operation only because of the d_ino field, no other transformation is necessary. Also a directory can become impure between two getdents(2) calls. This patch creates a cache for impure directories. Unlike the cache for merged directories, this one only contains entries with origin and is not refcounted but has a its lifetime tied to that of the dentry. Similarly to the merged cache, the impure cache is invalidated based on a version number. This version number is incremented when an entry with origin is added or removed from the directory. If the cache is empty, then the impure xattr is removed from the directory. This patch also fixes up handling of d_ino for the ".." entry if the parent directory is merged. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-20ovl: fix xattr get and set with selinuxMiklos Szeredi
inode_doinit_with_dentry() in SELinux wants to read the upper inode's xattr to get security label, and ovl_xattr_get() calls ovl_dentry_real(), which depends on dentry->d_inode, but d_inode is null and not initialized yet at this point resulting in an Oops. Fix by getting the upperdentry info from the inode directly in this case. Reported-by: Eryu Guan <eguan@redhat.com> Fixes: 09d8b586731b ("ovl: move __upperdentry to ovl_inode") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-17VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)David Howells
Firstly by applying the following with coccinelle's spatch: @@ expression SB; @@ -SB->s_flags & MS_RDONLY +sb_rdonly(SB) to effect the conversion to sb_rdonly(sb), then by applying: @@ expression A, SB; @@ ( -(!sb_rdonly(SB)) && A +!sb_rdonly(SB) && A | -A != (sb_rdonly(SB)) +A != sb_rdonly(SB) | -A == (sb_rdonly(SB)) +A == sb_rdonly(SB) | -!(sb_rdonly(SB)) +!sb_rdonly(SB) | -A && (sb_rdonly(SB)) +A && sb_rdonly(SB) | -A || (sb_rdonly(SB)) +A || sb_rdonly(SB) | -(sb_rdonly(SB)) != A +sb_rdonly(SB) != A | -(sb_rdonly(SB)) == A +sb_rdonly(SB) == A | -(sb_rdonly(SB)) && A +sb_rdonly(SB) && A | -(sb_rdonly(SB)) || A +sb_rdonly(SB) || A ) @@ expression A, B, SB; @@ ( -(sb_rdonly(SB)) ? 1 : 0 +sb_rdonly(SB) | -(sb_rdonly(SB)) ? A : B +sb_rdonly(SB) ? A : B ) to remove left over excess bracketage and finally by applying: @@ expression A, SB; @@ ( -(A & MS_RDONLY) != sb_rdonly(SB) +(bool)(A & MS_RDONLY) != sb_rdonly(SB) | -(A & MS_RDONLY) == sb_rdonly(SB) +(bool)(A & MS_RDONLY) == sb_rdonly(SB) ) to make comparisons against the result of sb_rdonly() (which is a bool) work correctly. Signed-off-by: David Howells <dhowells@redhat.com>
2017-07-13ovl: remove unneeded check for IS_ERR()Amir Goldstein
ovl_workdir_create() returns a valid index dentry or NULL. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-13ovl: fix random return value on mountAmir Goldstein
On failure to prepare_creds(), mount fails with a random return value, as err was last set to an integer cast of a valid lower mnt pointer or set to 0 if inodes index feature is enabled. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: 3fe6e52f0626 ("ovl: override creds with the ones from ...") Cc: <stable@vger.kernel.org> # v4.7 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: cleanup orphan index entriesAmir Goldstein
index entry should live only as long as there are upper or lower hardlinks. Cleanup orphan index entries on mount and when dropping the last overlay inode nlink. When about to cleanup or link up to orphan index and the index inode nlink > 1, admit that something went wrong and adjust overlay nlink to index inode nlink - 1 to prevent it from dropping below zero. This could happen when adding lower hardlinks underneath a mounted overlay and then trying to unlink them. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: add flag for upper in ovl_entryMiklos Szeredi
For rename, we need to ensure that an upper alias exists for hard links before attempting the operation. Introduce a flag in ovl_entry to track the state of the upper alias. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: cleanup bad and stale index entries on mountAmir Goldstein
Bad index entries are entries whose name does not match the origin file handle stored in trusted.overlay.origin xattr. Bad index entries could be a result of a system power off in the middle of copy up. Stale index entries are entries whose origin file handle is stale. Stale index entries could be a result of copying layers or removing lower entries while the overlay is not mounted. The case of copying layers should be detected earlier by the verification of upper root dir origin and index dir origin. Both bad and stale index entries are detected and removed on mount. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: verify index dir matches upper dirAmir Goldstein
An index dir contains persistent hardlinks to files in upper dir. Therefore, we must never mount an existing index dir with a differnt upper dir. Store the upper root dir file handle in index dir inode when index dir is created and verify the file handle before using an existing index dir on mount. Add an 'is_upper' flag to the overlay file handle encoding and set it when encoding the upper root file handle. This is not critical for index dir verification, but it is good practice towards a standard overlayfs file handle format for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: verify upper root dir matches lower root dirAmir Goldstein
When inodes index feature is enabled, verify that the file handle stored in upper root dir matches the lower root dir or fail to mount. If upper root dir has no stored file handle, encode and store the lower root dir file handle in overlay.origin xattr. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: introduce the inodes index dir featureAmir Goldstein
Create the index dir on mount. The index dir will contain hardlinks to upper inodes, named after the hex representation of their origin lower inodes. The index dir is going to be used to prevent breaking lower hardlinks on copy up and to implement overlayfs NFS export. Because the feature is not fully backward compat, enabling the feature is opt-in by config/module/mount option. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: generalize ovl_create_workdir()Amir Goldstein
Pass in the subdir name to create and specify if subdir is persistent or if it should be cleaned up on every mount. Move fallback to readonly mount on failure to create dir and print of error message into the helper. This function is going to be used for creating the persistent 'index' dir under workbasedir. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: get exclusive ownership on upper/work dirsAmir Goldstein
Bad things can happen if several concurrent overlay mounts try to use the same upperdir/workdir path. Try to get the 'inuse' advisory lock on upperdir and workdir. Fail mount if another overlay mount instance or another user holds the 'inuse' lock on these directories. Note that this provides no protection for concurrent overlay mount that use overlapping (i.e. descendant) upper/work dirs. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: move cache and version to ovl_inodeMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: use ovl_inode mutex to synchronize concurrent copy upAmir Goldstein
Use the new ovl_inode mutex to synchonize concurrent copy up instead of the super block copy up workqueue. Moving the synchronization object from the overlay dentry to the overlay inode is needed for synchonizing concurrent copy up of lower hardlinks to the same upper inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: move impure to ovl_inodeMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: move redirect to ovl_inodeMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: move __upperdentry to ovl_inodeMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: use i_private only as a keyMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: simplify getting inodeMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-07-04ovl: allocate an ovl_inode structAmir Goldstein
We need some more space to store overlay inode data in memory, so allocate overlay inodes from a slab of struct ovl_inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-05-29ovl: mark upper merge dir with type origin entries "impure"Amir Goldstein
An upper dir is marked "impure" to let ovl_iterate() know that this directory may contain non pure upper entries whose d_ino may need to be read from the origin inode. We already mark a non-merge dir "impure" when moving a non-pure child entry inside it, to let ovl_iterate() know not to iterate the non-merge dir directly. Mark also a merge dir "impure" when moving a non-pure child entry inside it and when copying up a child entry inside it. This can be used to optimize ovl_iterate() to perform a "pure merge" of upper and lower directories, merging the content of the directories, without having to read d_ino from origin inodes. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-05-18ovl: check on mount time if upper fs supports setting xattrAmir Goldstein
xattr are needed by overlayfs for setting opaque dir, redirect dir and copy up origin. Check at mount time by trying to set the overlay.opaque xattr on the workdir and if that fails issue a warning message. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-05-05ovl: check if all layers are on the same fsAmir Goldstein
Some features can only work when all layers are on the same fs. Test this condition during mount time, so features can check them later. Add helper ovl_same_sb() to return the common super block in case all layers are on the same fs. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-04-20ovl: check IS_APPEND() on real upper inodeAmir Goldstein
For overlay file open, check IS_APPEND() on the real upper inode inside d_real(), because the overlay inode does not have the S_APPEND flag and IS_APPEND() can only be checked at open time. Note that because overlayfs does not copy up the chattr inode flags (i.e. S_APPEND, S_IMMUTABLE), the IS_APPEND() check is only relevant for upper inodes that were set with chattr +a and not to lower inodes that had chattr +a before copy up. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-04-20ovl: Use designated initializersKees Cook
Prepare to mark sensitive kernel structures for randomization by making sure they're using designated initializers. These were identified during allyesconfig builds of x86, arm, and arm64, with most initializer fixes extracted from grsecurity. For these cases, use { }, which will be zero-filled, instead of undesignated NULLs. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-03-03Merge branch 'overlayfs-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "Because copy up can take a long time, serialized copy ups could be a big performance bottleneck. This update allows concurrent copy up of regular files eliminating this potential problem. There are also minor fixes" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: drop CAP_SYS_RESOURCE from saved mounter's credentials ovl: properly implement sync_filesystem() ovl: concurrent copy up of regular files ovl: introduce copy up waitqueue ovl: copy up regular file using O_TMPFILE ovl: rearrange code in ovl_copy_up_locked() ovl: check if upperdir fs supports O_TMPFILE
2017-03-02sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>Ingo Molnar
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h doing that for them. Note that even if the count where we need to add extra headers seems high, it's still a net win, because <linux/sched.h> is included in over 2,200 files ... Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-07ovl: drop CAP_SYS_RESOURCE from saved mounter's credentialsKonstantin Khlebnikov
If overlay was mounted by root then quota set for upper layer does not work because overlay now always use mounter's credentials for operations. Also overlay might deplete reserved space and inodes in ext4. This patch drops capability SYS_RESOURCE from saved credentials. This affects creation new files, whiteouts, and copy-up operations. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Fixes: 1175b6b8d963 ("ovl: do operations on underlying file system in mounter's context") Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-07ovl: properly implement sync_filesystem()Amir Goldstein
overlayfs syncs all inode pages on sync_filesystem(), but it also needs to call s_op->sync_fs() of upper fs for metadata sync. This fixes correctness of syncfs(2) as demonstrated by following xfs specific test: xfs_sync_stats() { echo $1 echo -n "xfs_log_force = " grep log /proc/fs/xfs/stat | awk '{ print $5 }' } xfs_sync_stats "before touch" touch x xfs_sync_stats "after touch" xfs_io -c syncfs . xfs_sync_stats "after syncfs" xfs_io -c fsync x xfs_sync_stats "after fsync" xfs_io -c fsync x xfs_sync_stats "after fsync #2" When this test is run in overlay mount over xfs, log force count does not increase with syncfs command. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-07ovl: introduce copy up waitqueueAmir Goldstein
The overlay sb 'copyup_wq' and overlay inode 'copying' condition variable are about to replace the upper sb rename_lock, as finer grained synchronization objects for concurrent copy up. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-07ovl: check if upperdir fs supports O_TMPFILEAmir Goldstein
This is needed for choosing between concurrent copyup using O_TMPFILE and legacy copyup using workdir+rename. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: fix return value of ovl_fill_superGeliang Tang
If kcalloc() failed, the return value of ovl_fill_super() is -EINVAL, not -ENOMEM. So this patch sets this value to -ENOMEM before calling kcalloc(), and sets it back to -EINVAL after calling kcalloc(). Signed-off-by: Geliang Tang <geliangtang@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: clean up kstat usageAl Viro
FWIW, there's a bit of abuse of struct kstat in overlayfs object creation paths - for one thing, it ends up with a very small subset of struct kstat (mode + rdev), for another it also needs link in case of symlinks and ends up passing it separately. IMO it would be better to introduce a separate object for that. In principle, we might even lift that thing into general API and switch ->mkdir()/->mknod()/->symlink() to identical calling conventions. Hell knows, perhaps ->create() as well... Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: show redirect_dir mount optionAmir Goldstein
Show the value of redirect_dir in /proc/mounts. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: allow redirect_dir to default to "on"Miklos Szeredi
This patch introduces a kernel config option and a module param. Both can be used independently to turn the default value of redirect_dir on or off. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: redirect on rename-dirMiklos Szeredi
Current code returns EXDEV when a directory would need to be copied up to move. We could copy up the directory tree in this case, but there's another, simpler solution: point to old lower directory from moved upper directory. This is achieved with a "trusted.overlay.redirect" xattr storing the path relative to the root of the overlay. After such attribute has been set, the directory can be moved without further actions required. This is a backward incompatible feature, old kernels won't be able to correctly mount an overlay containing redirected directories. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: lookup redirectsMiklos Szeredi
If a directory has the "trusted.overlay.redirect" xattr, it means that the value of the xattr should be used to find the underlying directory on the next lower layer. The redirect may be relative or absolute. Absolute redirects begin with a slash. A relative redirect means: instead of the current dentry's name use the value of the redirect to find the directory in the next lower layer. Relative redirects must not contain a slash. An absolute redirect means: look up the directory relative to the root of the overlay using the value of the redirect in the next lower layer. Redirects work on lower layers as well. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: fix nested overlayfs mountAmir Goldstein
When the upper overlayfs checks "trusted.overlay.*" xattr on the underlying overlayfs mount, it gets -EPERM, which confuses the upper overlayfs. Fix this by returning -EOPNOTSUPP instead of -EPERM from ovl_own_xattr_get() and ovl_own_xattr_set(). This behavior is consistent with the behavior of ovl_listxattr(), which filters out the private overlayfs xattrs. Note: nested overlays are deprecated. But this change makes sense regardless: these xattrs are private to the overlay and should always be hidden. Hence getting and setting them should indicate this. [SzMi: Use EOPNOTSUPP instead of ENODATA and use it for both getting and setting "trusted.overlay." xattrs. This is a perfectly valid error code for "we don't support this prefix", which is the case here.] Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: check namelenMiklos Szeredi
We already calculate f_namelen in statfs as the maximum of the name lengths provided by the filesystems taking part in the overlay. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: split super.cMiklos Szeredi
fs/overlayfs/super.c is the biggest of the overlayfs source files and it contains various utility functions as well as the rather complicated lookup code. Split these parts out to separate files. Before: 1446 fs/overlayfs/super.c After: 919 fs/overlayfs/super.c 267 fs/overlayfs/namei.c 235 fs/overlayfs/util.c 51 fs/overlayfs/ovl_entry.h Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: use d_is_dir()Miklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-22 01:30:14 +0000