summaryrefslogtreecommitdiffstats
path: root/fs/overlayfs
Commit message (Collapse)AuthorAgeFilesLines
* ovl: filter trusted xattr for non-adminMiklos Szeredi2017-05-291-1/+11
| | | | | | | | | | Filesystems filter out extended attributes in the "trusted." domain for unprivlieged callers. Overlay calls underlying filesystem's method with elevated privs, so need to do the filtering in overlayfs too. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: mark upper merge dir with type origin entries "impure"Amir Goldstein2017-05-296-58/+60
| | | | | | | | | | | | | | | | | | | | 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>
* ovl: mark upper dir with type origin entries "impure"Amir Goldstein2017-05-195-2/+79
| | | | | | | | | | | | | When moving a merge dir or non-dir with copy up origin into a non-merge upper dir (a.k.a pure upper dir), we are marking the target parent dir "impure". ovl_iterate() iterates pure upper dirs directly, because there is no need to filter out whiteouts and merge dir content with lower dir. But for the case of an "impure" upper dir, ovl_iterate() will not be able to iterate the real upper dir directly, because it will need to lookup the origin inode and use it to fill d_ino. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: remove unused arg from ovl_lookup_temp()Miklos Szeredi2017-05-193-6/+6
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: handle rename when upper doesn't support xattrAmir Goldstein2017-05-193-19/+20
| | | | | | | | | | | | | | On failure to set opaque/redirect xattr on rename, skip setting xattr and return -EXDEV. On failure to set opaque xattr when creating a new directory, -EIO is returned instead of -EOPNOTSUPP. Any failure to set those xattr will be recorded in super block and then setting any xattr on upper won't be attempted again. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: don't fail copy-up if upper doesn't support xattrMiklos Szeredi2017-05-181-1/+5
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: check on mount time if upper fs supports setting xattrAmir Goldstein2017-05-184-0/+38
| | | | | | | | | | | 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>
* ovl: fix creds leak in copy up error pathAmir Goldstein2017-05-181-5/+6
| | | | | | | Fixes: 42f269b92540 ("ovl: rearrange code in ovl_copy_up_locked()") Cc: <stable@vger.kernel.org> # v4.11 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: select EXPORTFSArnd Bergmann2017-05-151-0/+1
| | | | | | | | | | | | | | We get a link error when EXPORTFS is not enabled: ERROR: "exportfs_encode_fh" [fs/overlayfs/overlay.ko] undefined! ERROR: "exportfs_decode_fh" [fs/overlayfs/overlay.ko] undefined! This adds a Kconfig 'select' statement for overlayfs, the same way that it is done for the other users of exportfs. Fixes: 3a1e819b4e80 ("ovl: store file handle of lower inode on copy up") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* Merge branch 'overlayfs-linus' of ↵Linus Torvalds2017-05-108-50/+415
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs update from Miklos Szeredi: "The biggest part of this is making st_dev/st_ino on the overlay behave like a normal filesystem (i.e. st_ino doesn't change on copy up, st_dev is the same for all files and directories). Currently this only works if all layers are on the same filesystem, but future work will move the general case towards more sane behavior. There are also miscellaneous fixes, including fixes to handling append-only files. There's a small change in the VFS, but that only has an effect on overlayfs, since otherwise file->f_path.dentry->inode and file_inode(file) are always the same" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: update documentation w.r.t. constant inode numbers ovl: persistent inode numbers for upper hardlinks ovl: merge getattr for dir and nondir ovl: constant st_ino/st_dev across copy up ovl: persistent inode number for directories ovl: set the ORIGIN type flag ovl: lookup non-dir copy-up-origin by file handle ovl: use an auxiliary var for overlay root entry ovl: store file handle of lower inode on copy up ovl: check if all layers are on the same fs ovl: do not set overlay.opaque on non-dir create ovl: check IS_APPEND() on real upper inode vfs: ftruncate check IS_APPEND() on real upper inode ovl: Use designated initializers ovl: lockdep annotate of nested stacked overlayfs inode lock
| * ovl: persistent inode numbers for upper hardlinksAmir Goldstein2017-05-051-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An upper type non directory dentry that is a copy up target should have a reference to its lower copy up origin. There are three ways for an upper type dentry to be instantiated: 1. A lower type dentry that is being copied up 2. An entry that is found in upper dir by ovl_lookup() 3. A negative dentry is hardlinked to an upper type dentry In the first case, the lower reference is set before copy up. In the second case, the lower reference is found by ovl_lookup(). In the last case of hardlinked upper dentry, it is not easy to update the lower reference of the negative dentry. Instead, drop the newly hardlinked negative dentry from dcache and let the next access call ovl_lookup() to find its lower reference. This makes sure that the inode number reported by stat(2) after the hardlink is created is the same inode number that will be reported by stat(2) after mount cycle, which is the inode number of the lower copy up origin of the hardlink source. NOTE that this does not fix breaking of lower hardlinks on copy up, but only fixes the case of lower nlink == 1, whose upper copy up inode is hardlinked in upper dir. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: merge getattr for dir and nondirMiklos Szeredi2017-05-053-64/+30
| | | | | | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: constant st_ino/st_dev across copy upAmir Goldstein2017-05-051-1/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When all layers are on the same underlying filesystem, let stat(2) return st_dev/st_ino values of the copy up origin inode if it is known. This results in constant st_ino/st_dev representation of files in an overlay mount before and after copy up. When the underlying filesystem support NFS exportfs, the result is also persistent st_ino/st_dev representation before and after mount cycle. Lower hardlinks are broken on copy up to different upper files, so we cannot use the lower origin st_ino for those different files, even for the same fs case. When all overlay layers are on the same fs, use overlay st_dev for non-dirs to get the correct result from du -x. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: persistent inode number for directoriesAmir Goldstein2017-05-051-4/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | stat(2) on overlay directories reports the overlay temp inode number, which is constant across copy up, but is not persistent. When all layers are on the same fs, report the copy up origin inode number for directories. This inode number is persistent, unique across the overlay mount and constant across copy up. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: set the ORIGIN type flagAmir Goldstein2017-05-052-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | For directory entries, non zero oe->numlower implies OVL_TYPE_MERGE. Define a new type flag OVL_TYPE_ORIGIN to indicate that an entry holds a reference to its lower copy up origin. For directory entries ORIGIN := MERGE && UPPER. For non-dir entries ORIGIN means that a lower type dentry has been recently copied up or that we were able to find the copy up origin from overlay.origin xattr. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: lookup non-dir copy-up-origin by file handleAmir Goldstein2017-05-051-0/+132
| | | | | | | | | | | | | | | | | | | | | | | | If overlay.origin xattr is found on a non-dir upper inode try to get lower dentry by calling exportfs_decode_fh(). On failure to lookup by file handle to lower layer, do not lookup the copy up origin by name, because the lower found by name could be another file in case the upper file was renamed. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: use an auxiliary var for overlay root entryAmir Goldstein2017-05-051-5/+4
| | | | | | | | | | Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: store file handle of lower inode on copy upAmir Goldstein2017-05-052-0/+118
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sometimes it is interesting to know if an upper file is pure upper or a copy up target, and if it is a copy up target, it may be interesting to find the copy up origin. This will be used to preserve lower inode numbers across copy up. Store the lower inode file handle in upper inode extended attribute overlay.origin on copy up to use it later for these cases. Store the lower filesystem uuid along side the file handle, so we can validate that we are looking for the origin file in the original fs. If lower fs does not support NFS export ops store a zero sized xattr so we can always use the overlay.origin xattr to distinguish between a copy up and a pure upper inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: check if all layers are on the same fsAmir Goldstein2017-05-054-0/+18
| | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: do not set overlay.opaque on non-dir createAmir Goldstein2017-04-261-1/+1
| | | | | | | | | | | | | | | | | | | | The optimization for opaque dir create was wrongly being applied also to non-dir create. Fixes: 97c684cc9110 ("ovl: create directories inside merged parent opaque") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> # v4.10
| * ovl: check IS_APPEND() on real upper inodeAmir Goldstein2017-04-201-3/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: Use designated initializersKees Cook2017-04-202-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: lockdep annotate of nested stacked overlayfs inode lockAmir Goldstein2017-03-081-0/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An overlayfs instance can be the lower layer of another overlayfs instance. This setup triggers a lockdep splat of possible recursive locking of sb->s_type->i_mutex_key in iterate_dir(). Trimmed snip: [ INFO: possible recursive locking detected ] bash/2468 is trying to acquire lock: &sb->s_type->i_mutex_key#14, at: iterate_dir+0x7d/0x15c but task is already holding lock: &sb->s_type->i_mutex_key#14, at: iterate_dir+0x7d/0x15c One problem observed with this splat is that ovl_new_inode() does not call lockdep_annotate_inode_mutex_key() to annotate the dir inode lock as &sb->s_type->i_mutex_dir_key like other fs do. The other problem is that the 2 nested levels of overlayfs inode lock are annotated using the same key, which is the cause of the false positive lockdep warning. Fix this by annotating overlayfs inode lock in ovl_fill_inode() according to stack level of the super block instance and use different key for dir vs. non-dir like other fs do. Here is an edited snip from /proc/lockdep_chains after iterate_dir() of nested overlayfs: [...] &ovl_i_mutex_dir_key[depth] (stack_depth=2) [...] &ovl_i_mutex_dir_key[depth]#2 (stack_depth=1) [...] &type->i_mutex_dir_key (stack_depth=0) Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | overlayfs: remove now unnecessary header file includeLinus Torvalds2017-03-081-1/+0
|/ | | | | | | | | | | | This removes the extra include header file that was added in commit e58bc927835a "Pull overlayfs updates from Miklos Szeredi" now that it is no longer needed. There are probably other such includes that got added during the scheduler header splitup series, but this is the one that annoyed me personally and I know about. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'overlayfs-linus' of ↵Linus Torvalds2017-03-035-27/+148
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| * ovl: drop CAP_SYS_RESOURCE from saved mounter's credentialsKonstantin Khlebnikov2017-02-071-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: properly implement sync_filesystem()Amir Goldstein2017-02-071-0/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: concurrent copy up of regular filesAmir Goldstein2017-02-071-4/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that copy up of regular file is done using O_TMPFILE, we don't need to hold rename_lock throughout copy up. Use the copy up waitqueue to synchronize concurrent copy up of the same file. Different regular files can be copied up concurrently. The upper dir inode_lock is taken instead of rename_lock, because it is needed for lookup and later for linking the temp file, but it is released while copying up data. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: introduce copy up waitqueueAmir Goldstein2017-02-074-0/+35
| | | | | | | | | | | | | | | | | | | | 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>
| * ovl: copy up regular file using O_TMPFILEAmir Goldstein2017-02-071-7/+20
| | | | | | | | | | | | | | | | | | | | In preparation for concurrent copy up, implement copy up of regular file as O_TMPFILE that is linked to upperdir instead of a file in workdir that is moved to upperdir. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: rearrange code in ovl_copy_up_locked()Amir Goldstein2017-02-071-24/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | As preparation to implementing copy up with O_TMPFILE, name the variable for dentry before final rename 'temp' and assign it to 'newdentry' only after rename. Also lookup upper dentry before looking up temp dentry and move ovl_set_timestamps() into ovl_copy_up_locked(), because that is going to be more convenient for upcoming change. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: check if upperdir fs supports O_TMPFILEAmir Goldstein2017-02-073-0/+20
| | | | | | | | | | | | | | | | 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>
* | Merge branch 'rebased-statx' of ↵Linus Torvalds2017-03-033-9/+14
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs 'statx()' update from Al Viro. This adds the new extended stat() interface that internally subsumes our previous stat interfaces, and allows user mode to specify in more detail what kind of information it wants. It also allows for some explicit synchronization information to be passed to the filesystem, which can be relevant for network filesystems: is the cached value ok, or do you need open/close consistency, or what? From David Howells. Andreas Dilger points out that the first version of the extended statx interface was posted June 29, 2010: https://www.spinics.net/lists/linux-fsdevel/msg33831.html * 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: statx: Add a system call to make enhanced file info available
| * | statx: Add a system call to make enhanced file info availableDavid Howells2017-03-023-9/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar2017-03-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. 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>
* | | sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>Ingo Molnar2017-03-025-0/+5
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* / ovl: fix possible use after free on redirect dir lookupAmir Goldstein2017-01-181-9/+18
|/ | | | | | | | | | | | | | | | | | | ovl_lookup_layer() iterates on path elements of d->name.name but also frees and allocates a new pointer for d->name.name. For the case of lookup in upper layer, the initial d->name.name pointer is stable (dentry->d_name), but for lower layers, the initial d->name.name can be d->redirect, which can be freed during iteration. [SzM] Keep the count of remaining characters in the redirect path and calculate the current position from that. This works becuase only the prefix is modified, the ending always stays the same. Fixes: 02b69b284cd7 ("ovl: lookup redirects") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* Merge uncontroversial parts of branch 'readlink' of ↵Linus Torvalds2016-12-171-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull partial readlink cleanups from Miklos Szeredi. This is the uncontroversial part of the readlink cleanup patch-set that simplifies the default readlink handling. Miklos and Al are still discussing the rest of the series. * git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: vfs: make generic_readlink() static vfs: remove ".readlink = generic_readlink" assignments vfs: default to generic_readlink() vfs: replace calling i_op->readlink with vfs_readlink() proc/self: use generic_readlink ecryptfs: use vfs_get_link() bad_inode: add missing i_op initializers
| * vfs: remove ".readlink = generic_readlink" assignmentsMiklos Szeredi2016-12-091-1/+0
| | | | | | | | | | | | | | | | | | | | | | If .readlink == NULL implies generic_readlink(). Generated by: to_del="\.readlink.*=.*generic_readlink" for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | Merge branch 'overlayfs-linus' of ↵Linus Torvalds2016-12-1610-784/+1084
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This update contains: - try to clone on copy-up - allow renaming a directory - split source into managable chunks - misc cleanups and fixes It does not contain the read-only fd data inconsistency fix, which Al didn't like. I'll leave that to the next year..." * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (36 commits) ovl: fix reStructuredText syntax errors in documentation ovl: fix return value of ovl_fill_super ovl: clean up kstat usage ovl: fold ovl_copy_up_truncate() into ovl_copy_up() ovl: create directories inside merged parent opaque ovl: opaque cleanup ovl: show redirect_dir mount option ovl: allow setting max size of redirect ovl: allow redirect_dir to default to "on" ovl: check for emptiness of redirect dir ovl: redirect on rename-dir ovl: lookup redirects ovl: consolidate lookup for underlying layers ovl: fix nested overlayfs mount ovl: check namelen ovl: split super.c ovl: use d_is_dir() ovl: simplify lookup ovl: check lower existence of rename target ovl: rename: simplify handling of lower/merged directory ...
| * | ovl: fix return value of ovl_fill_superGeliang Tang2016-12-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | ovl: clean up kstat usageAl Viro2016-12-164-39/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | ovl: fold ovl_copy_up_truncate() into ovl_copy_up()Amir Goldstein2016-12-163-37/+13
| | | | | | | | | | | | | | | | | | | | | This removes code duplication. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | ovl: create directories inside merged parent opaqueAmir Goldstein2016-12-161-2/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The benefit of making directories opaque on creation is that lookups can stop short when they reach the original created directory, instead of continue lookup the entire depth of parent directory stack. The best case is overlay with N layers, performing lookup for first level directory, which exists only in upper. In that case, there will be only one lookup instead of N. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | ovl: opaque cleanupMiklos Szeredi2016-12-164-31/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | oe->opaque is set for a) whiteouts b) directories having the "trusted.overlay.opaque" xattr Case b can be simplified, since setting the xattr always implies setting oe->opaque. Also once set, the opaque flag is never cleared. Don't need to set opaque flag for non-directories. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | ovl: show redirect_dir mount optionAmir Goldstein2016-12-161-0/+3
| | | | | | | | | | | | | | | | | | | | | 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>
| * | ovl: allow setting max size of redirectMiklos Szeredi2016-12-161-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a module option to allow tuning the max size of absolute redirects. Default is 256. Size of relative redirects is naturally limited by the the underlying filesystem's max filename length (usually 255). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | ovl: allow redirect_dir to default to "on"Miklos Szeredi2016-12-162-0/+19
| | | | | | | | | | | | | | | | | | | | | 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>
| * | ovl: check for emptiness of redirect dirAmir Goldstein2016-12-161-9/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before introducing redirect_dir feature, the condition !ovl_lower_positive(dentry) for a directory, implied that it is a pure upper directory, which may be removed if empty. Now that directory can be redirect, it is possible that upper does not cover any lower (i.e. !ovl_lower_positive(dentry)), but the directory is a merge (with redirected path) and maybe non empty. Check for this case in ovl_remove_upper(). This change fixes the following test case from rename-pop-dir.py of unionmount-testsuite: """Remove dir and rename old name""" d = ctx.non_empty_dir() d2 = ctx.no_dir() ctx.rmdir(d, err=ENOTEMPTY) ctx.rename(d, d2) ctx.rmdir(d, err=ENOENT) ctx.rmdir(d2, err=ENOTEMPTY) ./run --ov rename-pop-dir /mnt/a/no_dir103: Expected error (Directory not empty) was not produced Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | ovl: redirect on rename-dirMiklos Szeredi2016-12-166-28/+176
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 16:16:13 +0000