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path: root/fs/overlayfs/super.c
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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>
2017-07-13ovl: 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>
2016-12-16ovl: simplify lookupMiklos Szeredi
If encountering a non-directory, then stop looking at lower layers. In this case the oe->opaque flag is not set anymore, which doesn't matter since existence of lower file is now checked at remove/rename time. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: get rid of PURE typeMiklos Szeredi
The remainging uses of __OVL_PATH_PURE can be replaced by ovl_dentry_is_opaque(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: check lower existence when removingMiklos Szeredi
Currently ovl_lookup() checks existence of lower file even if there's a non-directory on upper (which is always opaque). This is done so that remove can decide whether a whiteout is needed or not. It would be better to defer this check to unlink, since most of the time the gathered information about opaqueness will be unused. This adds a helper ovl_lower_positive() that checks if there's anything on the lower layer(s). The following patches also introduce changes to how the "opaque" attribute is updated on directories: this attribute is added when the directory is creted or moved over a whiteout or object covering something on the lower layer. However following changes will allow the attribute to remain on the directory after being moved, even if the new location doesn't cover anything. Because of this, we need to check lower layers even for opaque directories, so that whiteout is only created when necessary. This function will later be also used to decide about marking a directory opaque, so deal with negative dentries as well. When dealing with negative, it's enough to check for being a whiteout If the dentry is positive but not upper then it also obviously needs whiteout/opaque. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: add ovl_dentry_is_whiteout()Miklos Szeredi
And use it instead of ovl_dentry_is_opaque() where appropriate. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: treat special files like a regular fsMiklos Szeredi
No sense in opening special files on the underlying layers, they work just as well if opened on the overlay. Side effect is that it's no longer possible to connect one side of a pipe opened on overlayfs with the other side opened on the underlying layer. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-11-29ovl: fix d_real() for stacked fsMiklos Szeredi
Handling of recursion in d_real() is completely broken. Recursion is only done in the 'inode != NULL' case. But when opening the file we have 'inode == NULL' hence d_real() will return an overlay dentry. This won't work since overlayfs doesn't define its own file operations, so all file ops will fail. Fix by doing the recursion first and the check against the inode second. Bash script to reproduce the issue written by Quentin: - 8< - - - - - 8< - - - - - 8< - - - - - 8< - - - - tmpdir=$(mktemp -d) pushd ${tmpdir} mkdir -p {upper,lower,work} echo -n 'rocks' > lower/ksplice mount -t overlay level_zero upper -o lowerdir=lower,upperdir=upper,workdir=work cat upper/ksplice tmpdir2=$(mktemp -d) pushd ${tmpdir2} mkdir -p {upper,work} mount -t overlay level_one upper -o lowerdir=${tmpdir}/upper,upperdir=upper,workdir=work ls -l upper/ksplice cat upper/ksplice - 8< - - - - - 8< - - - - - 8< - - - - - 8< - - - - Reported-by: Quentin Casasnovas <quentin.casasnovas@oracle.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 2d902671ce1c ("vfs: merge .d_select_inode() into .d_real()") Cc: <stable@vger.kernel.org> # v4.8+
2016-10-31ovl: update S_ISGID when setting posix ACLsMiklos Szeredi
This change fixes xfstest generic/375, which failed to clear the setgid bit in the following test case on overlayfs: touch $testfile chown 100:100 $testfile chmod 2755 $testfile _runas -u 100 -g 101 -- setfacl -m u::rwx,g::rwx,o::rwx $testfile Reported-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Tested-by: Amir Goldstein <amir73il@gmail.com> Fixes: d837a49bd57f ("ovl: fix POSIX ACL setting") Cc: <stable@vger.kernel.org> # v4.8
2016-10-14Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more misc uaccess and vfs updates from Al Viro: "The rest of the stuff from -next (more uaccess work) + assorted fixes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: score: traps: Add missing include file to fix build error fs/super.c: don't fool lockdep in freeze_super() and thaw_super() paths fs/super.c: fix race between freeze_super() and thaw_super() overlayfs: Fix setting IOP_XATTR flag iov_iter: kernel-doc import_iovec() and rw_copy_check_uvector() blackfin: no access_ok() for __copy_{to,from}_user() arm64: don't zero in __copy_from_user{,_inatomic} arm: don't zero in __copy_from_user_inatomic()/__copy_from_user() arc: don't leak bits of kernel stack into coredump alpha: get rid of tail-zeroing in __copy_user()
2016-10-14Merge branch 'overlayfs-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This update contains fixes to the "use mounter's permission to access underlying layers" area, and miscellaneous other fixes and cleanups. No new features this time" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: use vfs_get_link() vfs: add vfs_get_link() helper ovl: use generic_readlink ovl: explain error values when removing acl from workdir ovl: Fix info leak in ovl_lookup_temp() ovl: during copy up, switch to mounter's creds early ovl: lookup: do getxattr with mounter's permission ovl: copy_up_xattr(): use strnlen
2016-10-14overlayfs: Fix setting IOP_XATTR flagVivek Goyal
ovl_fill_super calls ovl_new_inode to create a root inode for the new superblock before initializing sb->s_xattr. This wrongly causes IOP_XATTR to be cleared in i_opflags of the new inode, causing SELinux to log the following message: SELinux: (dev overlay, type overlay) has no xattr support Fix this by initializing sb->s_xattr and similar fields before calling ovl_new_inode. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>