kernel/linux.git/fs/omfs/dir.c, branch v6.19.12

Change inode_operations.mkdir to return struct dentry *

2025-02-27T19:00:17+00:00

Some filesystems, such as NFS, cifs, ceph, and fuse, do not have complete control of sequencing on the actual filesystem (e.g. on a different server) and may find that the inode created for a mkdir request already exists in the icache and dcache by the time the mkdir request returns. For example, if the filesystem is mounted twice the directory could be visible on the other mount before it is on the original mount, and a pair of name_to_handle_at(), open_by_handle_at() calls could instantiate the directory inode with an IS_ROOT() dentry before the first mkdir returns. This means that the dentry passed to ->mkdir() may not be the one that is associated with the inode after the ->mkdir() completes. Some callers need to interact with the inode after the ->mkdir completes and they currently need to perform a lookup in the (rare) case that the dentry is no longer hashed. This lookup-after-mkdir requires that the directory remains locked to avoid races. Planned future patches to lock the dentry rather than the directory will mean that this lookup cannot be performed atomically with the mkdir. To remove this barrier, this patch changes ->mkdir to return the resulting dentry if it is different from the one passed in. Possible returns are: NULL - the directory was created and no other dentry was used ERR_PTR() - an error occurred non-NULL - this other dentry was spliced in This patch only changes file-systems to return "ERR_PTR(err)" instead of "err" or equivalent transformations. Subsequent patches will make further changes to some file-systems to return a correct dentry. Not all filesystems reliably result in a positive hashed dentry: - NFS, cifs, hostfs will sometimes need to perform a lookup of the name to get inode information. Races could result in this returning something different. Note that this lookup is non-atomic which is what we are trying to avoid. Placing the lookup in filesystem code means it only happens when the filesystem has no other option. - kernfs and tracefs leave the dentry negative and the ->revalidate operation ensures that lookup will be called to correctly populate the dentry. This could be fixed but I don't think it is important to any of the users of vfs_mkdir() which look at the dentry. The recommendation to use d_drop();d_splice_alias() is ugly but fits with current practice. A planned future patch will change this. Reviewed-by: Jeff Layton Reviewed-by: Jan Kara Signed-off-by: NeilBrown Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de Signed-off-by: Christian Brauner

omfs: convert to ctime accessor functions

2023-07-24T08:30:02+00:00

In later patches, we're going to change how the inode's ctime field is used. Switch to using accessor functions instead of raw accesses of inode->i_ctime. Acked-by: Bob Copeland Signed-off-by: Jeff Layton Reviewed-by: Jan Kara Message-Id: <20230705190309.579783-61-jlayton@kernel.org> Signed-off-by: Christian Brauner

fs: port ->rename() to pass mnt_idmap

2023-01-19T08:24:26+00:00

Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft)

fs: port ->mkdir() to pass mnt_idmap

2023-01-19T08:24:26+00:00

fs: port ->create() to pass mnt_idmap

2023-01-19T08:24:25+00:00

fs: make helpers idmap mount aware

2021-01-24T13:27:20+00:00

Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 209

2019-05-30T18:29:53+00:00

Based on 1 normalized pattern(s): released under gpl v2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 15 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Steve Winslow Reviewed-by: Allison Randal Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528171438.895196075@linutronix.de Signed-off-by: Greg Kroah-Hartman

omfs_lookup(): report IO errors, use d_splice_alias()

2018-05-22T18:27:58+00:00

Signed-off-by: Al Viro

Merge remote-tracking branch 'ovl/rename2' into for-linus

2016-10-11T03:02:51+00:00

fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps

2016-09-28T01:06:22+00:00

CURRENT_TIME_SEC is not y2038 safe. current_time() will be transitioned to use 64 bit time along with vfs in a separate patch. There is no plan to transistion CURRENT_TIME_SEC to use y2038 safe time interfaces. current_time() will also be extended to use superblock range checking parameters when range checking is introduced. This works because alloc_super() fills in the the s_time_gran in super block to NSEC_PER_SEC. Signed-off-by: Deepa Dinamani Acked-by: Jan Kara Signed-off-by: Al Viro