kernel/fs/overlayfs/readdir.c, branch linux-5.1.y

ovl: fix wrong use of impure dir cache in ovl_iterate()

2018-07-17T14:04:34Z

Only upper dir can be impure, but if we are in the middle of iterating a lower real dir, dir could be copied up and marked impure. We only want the impure cache if we started iterating a real upper dir to begin with. Aditya Kali reported that the following reproducer hits the WARN_ON(!cache->refcount) in ovl_get_cache(): docker run --rm drupal:8.5.4-fpm-alpine \ sh -c 'cd /var/www/html/vendor/symfony && \ chown -R www-data:www-data . && ls -l .' Reported-by: Aditya Kali Tested-by: Aditya Kali Fixes: 4edb83bb1041 ('ovl: constant d_ino for non-merge dirs') Cc: # v4.14 Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: consistent d_ino for non-samefs with xino

2018-04-12T10:04:50Z

When overlay layers are not all on the same fs, but all inode numbers of underlying fs do not use the high 'xino' bits, overlay st_ino values are constant and persistent. In that case, relax non-samefs constraint for consistent d_ino and always iterate non-merge dir using ovl_fill_real() actor so we can remap lower inode numbers to unique lower fs range. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: whiteout orphan index entries on mount

2018-01-24T10:25:56Z

Orphan index entries are non-dir index entries whose union nlink count dropped to zero. With index=on, orphan index entries are removed on mount. With NFS export feature enabled, orphan index entries are replaced with white out index entries to block future open by handle from opening the lower file. When dir index has a stale 'upper' xattr, we assume that the upper dir was removed and we treat the dir index as orphan entry that needs to be whited out or removed. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: simplify arguments to ovl_check_origin_fh()

2018-01-24T09:19:46Z

Pass the fs instance with lower_layers array instead of the dentry lowerstack array to ovl_check_origin_fh(), because the dentry members of lowerstack play no role in this helper. This change simplifies the argument list of ovl_check_origin(), ovl_cleanup_index() and ovl_verify_index(). Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: take mnt_want_write() for removing impure xattr

2018-01-19T16:43:24Z

The optimization in ovl_cache_get_impure() that tries to remove an unneeded "impure" xattr needs to take mnt_want_write() on upper fs. Fixes: 4edb83bb1041 ("ovl: constant d_ino for non-merge dirs") Cc: #v4.14 Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: take lower dir inode mutex outside upper sb_writers lock

2018-01-19T16:43:23Z

The functions ovl_lower_positive() and ovl_check_empty_dir() both take inode mutex on the real lower dir under ovl_want_write() which takes the upper_mnt sb_writers lock. While this is not a clear locking order or layering violation, it creates an undesired lock dependency between two unrelated layers for no good reason. This lock dependency materializes to a false(?) positive lockdep warning when calling rmdir() on a nested overlayfs, where both nested and underlying overlayfs both use the same fs type as upper layer. rmdir() on the nested overlayfs creates the lock chain: sb_writers of upper_mnt (e.g. tmpfs) in ovl_do_remove() ovl_i_mutex_dir_key[] of lower overlay dir in ovl_lower_positive() rmdir() on the underlying overlayfs creates the lock chain in reverse order: ovl_i_mutex_dir_key[] of lower overlay dir in vfs_rmdir() sb_writers of nested upper_mnt (e.g. tmpfs) in ovl_do_remove() To rid of the unneeded locking dependency, move both ovl_lower_positive() and ovl_check_empty_dir() to before ovl_want_write() in rmdir() and rename() implementation. This change spreads the pieces of ovl_check_empty_and_clear() directly inside the rmdir()/rename() implementations so the helper is no longer needed and removed. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: fix failure to fsync lower dir

2018-01-19T12:54:33Z

As a writable mount, it is not expected for overlayfs to return EINVAL/EROFS for fsync, even if dir/file is not changed. This commit fixes the case of fsync of directory, which is easier to address, because overlayfs already implements fsync file operation for directories. The problem reported by Raphael is that new PostgreSQL 10.0 with a database in overlayfs where lower layer in squashfs fails to start. The failure is due to fsync error, when PostgreSQL does fsync on all existing db directories on startup and a specific directory exists lower layer with no changes. Reported-by: Raphael Hertzog Cc: # v3.18 Signed-off-by: Amir Goldstein Tested-by: Raphaël Hertzog Signed-off-by: Miklos Szeredi

ovl: fix overlay: warning prefix

2017-12-14T10:14:52Z

Conform two stray warning messages to the standard overlayfs: prefix. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: update ctx->pos on impure dir iteration

2017-12-11T10:28:11Z

This fixes a regression with readdir of impure dir in overlayfs that is shared to VM via 9p fs. Reported-by: Miguel Bernal Marin Fixes: 4edb83bb1041 ("ovl: constant d_ino for non-merge dirs") Cc: #4.14 Signed-off-by: Amir Goldstein Tested-by: Miguel Bernal Marin Signed-off-by: Miklos Szeredi

Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

2017-11-17T21:36:59Z

Pull overlayfs updates from Miklos Szeredi: - Report constant st_ino values across copy-up even if underlying layers are on different filesystems, but using different st_dev values for each layer. Ideally we'd report the same st_dev across the overlay, and it's possible to do for filesystems that use only 32bits for st_ino by unifying the inum space. It would be nice if it wasn't a choice of 32 or 64, rather filesystems could report their current maximum (that could change on resize, so it wouldn't be set in stone). - miscellaneus fixes and a cleanup of ovl_fill_super(), that was long overdue. - created a path_put_init() helper that clears out the pointers after putting the ref. I think this could be useful elsewhere, so added it to * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (30 commits) ovl: remove unneeded arg from ovl_verify_origin() ovl: Put upperdentry if ovl_check_origin() fails ovl: rename ufs to ofs ovl: clean up getting lower layers ovl: clean up workdir creation ovl: clean up getting upper layer ovl: move ovl_get_workdir() and ovl_get_lower_layers() ovl: reduce the number of arguments for ovl_workdir_create() ovl: change order of setup in ovl_fill_super() ovl: factor out ovl_free_fs() helper ovl: grab reference to workbasedir early ovl: split out ovl_get_indexdir() from ovl_fill_super() ovl: split out ovl_get_lower_layers() from ovl_fill_super() ovl: split out ovl_get_workdir() from ovl_fill_super() ovl: split out ovl_get_upper() from ovl_fill_super() ovl: split out ovl_get_lowerstack() from ovl_fill_super() ovl: split out ovl_get_workpath() from ovl_fill_super() ovl: split out ovl_get_upperpath() from ovl_fill_super() ovl: use path_put_init() in error paths for ovl_fill_super() vfs: add path_put_init() ...