kernel/linux.git/fs/overlayfs/readdir.c, branch v4.9.331

ovl: fix failure to fsync lower dir

2018-02-17T12:21:20+00:00

commit d796e77f1dd541fe34481af2eee6454688d13982 upstream. 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 Signed-off-by: Amir Goldstein Tested-by: Raphaël Hertzog Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: proper cleanup of workdir

2016-09-01T09:11:59+00:00

When mounting overlayfs it needs a clean "work" directory under the supplied workdir. Previously the mount code removed this directory if it already existed and created a new one. If the removal failed (e.g. directory was not empty) then it fell back to a read-only mount not using the workdir. While this has never been reported, it is possible to get a non-empty "work" dir from a previous mount of overlayfs in case of crash in the middle of an operation using the work directory. In this case the left over state should be discarded and the overlay filesystem will be consistent, guaranteed by the atomicity of operations on moving to/from the workdir to the upper layer. This patch implements cleaning out any files left in workdir. It is implemented using real recursion for simplicity, but the depth is limited to 2, because the worst case is that of a directory containing whiteouts under "work". Signed-off-by: Miklos Szeredi Cc:

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

2016-05-28T00:14:05+00:00

Pull vfs fixes from Al Viro: "Followups to the parallel lookup work: - update docs - restore killability of the places that used to take ->i_mutex killably now that we have down_write_killable() merged - Additionally, it turns out that I missed a prerequisite for security_d_instantiate() stuff - ->getxattr() wasn't the only thing that could be called before dentry is attached to inode; with smack we needed the same treatment applied to ->setxattr() as well" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: switch ->setxattr() to passing dentry and inode separately switch xattr_handler->set() to passing dentry and inode separately restore killability of old mutex_lock_killable(&inode->i_mutex) users add down_write_killable_nested() update D/f/directory-locking

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

2016-05-27T23:44:39+00:00

Pull overlayfs update from Miklos Szeredi: "The meat of this is a change to use the mounter's credentials for operations that require elevated privileges (such as whiteout creation). This fixes behavior under user namespaces as well as being a nice cleanup" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: Do d_type check only if work dir creation was successful ovl: update documentation ovl: override creds with the ones from the superblock mounter

ovl: override creds with the ones from the superblock mounter

2016-05-27T06:55:26+00:00

In user namespace the whiteout creation fails with -EPERM because the current process isn't capable(CAP_SYS_ADMIN) when setting xattr. A simple reproducer: $ mkdir upper lower work merged lower/dir $ sudo mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merged $ unshare -m -p -f -U -r bash Now as root in the user namespace: \# touch merged/dir/{1,2,3} # this will force a copy up of lower/dir \# rm -fR merged/* This ends up failing with -EPERM after the files in dir has been correctly deleted: unlinkat(4, "2", 0) = 0 unlinkat(4, "1", 0) = 0 unlinkat(4, "3", 0) = 0 close(4) = 0 unlinkat(AT_FDCWD, "merged/dir", AT_REMOVEDIR) = -1 EPERM (Operation not permitted) Interestingly, if you don't place files in merged/dir you can remove it, meaning if upper/dir does not exist, creating the char device file works properly in that same location. This patch uses ovl_sb_creator_cred() to get the cred struct from the superblock mounter and override the old cred with these new ones so that the whiteout creation is possible because overlay is wrong in assuming that the creds it will get with prepare_creds will be in the initial user namespace. The old cap_raise game is removed in favor of just overriding the old cred struct. This patch also drops from ovl_copy_up_one() the following two lines: override_cred->fsuid = stat->uid; override_cred->fsgid = stat->gid; This is because the correct uid and gid are taken directly with the stat struct and correctly set with ovl_set_attr(). Signed-off-by: Antonio Murdaca Signed-off-by: Miklos Szeredi

restore killability of old mutex_lock_killable(&inode->i_mutex) users

2016-05-26T04:13:25+00:00

The ones that are taking it exclusive, that is... Signed-off-by: Al Viro

parallel lookups: actual switch to rwsem

2016-05-02T23:49:28+00:00

ta-da! The main issue is the lack of down_write_killable(), so the places like readdir.c switched to plain inode_lock(); once killable variants of rwsem primitives appear, that'll be dealt with. lockdep side also might need more work Signed-off-by: Al Viro

ovl: rename is_merge to is_lowest

2016-03-21T16:31:46+00:00

The 'is_merge' is an historical naming from when only a single lower layer could exist. With the introduction of multiple lower layers the meaning of this flag was changed to mean only the "lowest layer" (while all lower layers were being merged). So now 'is_merge' is inaccurate and hence renaming to 'is_lowest' Signed-off-by: Miklos Szeredi

ovl: Ensure upper filesystem supports d_type

2016-03-21T16:31:45+00:00

In some instances xfs has been created with ftype=0 and there if a file on lower fs is removed, overlay leaves a whiteout in upper fs but that whiteout does not get filtered out and is visible to overlayfs users. And reason it does not get filtered out because upper filesystem does not report file type of whiteout as DT_CHR during iterate_dir(). So it seems to be a requirement that upper filesystem support d_type for overlayfs to work properly. Do this check during mount and fail if d_type is not supported. Suggested-by: Dave Chinner Signed-off-by: Vivek Goyal Signed-off-by: Miklos Szeredi

wrappers for ->i_mutex access

2016-01-22T23:04:28+00:00

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro