linux/fs/cachefiles
Al Viro a8b0026847 rename(): avoid a deadlock in the case of parents having no common ancestor
... and fix the directory locking documentation and proof of correctness.
Holding ->s_vfs_rename_mutex *almost* prevents ->d_parent changes; the
case where we really don't want it is splicing the root of disconnected
tree to somewhere.

In other words, ->s_vfs_rename_mutex is sufficient to stabilize "X is an
ancestor of Y" only if X and Y are already in the same tree.  Otherwise
it can go from false to true, and one can construct a deadlock on that.

Make lock_two_directories() report an error in such case and update the
callers of lock_rename()/lock_rename_child() to handle such errors.

And yes, such conditions are not impossible to create ;-/

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2023-11-25 02:54:14 -05:00
..
cache.c cachefiles: Check that the backing filesystem supports tmpfiles 2022-01-21 21:36:28 +00:00
daemon.c cachefiles: enable on-demand read mode 2022-05-18 00:11:18 +08:00
error_inject.c fs/cachefiles: simplify one-level sysctl registration for cachefiles_sysctls 2023-04-13 11:49:35 -07:00
interface.c fs: port vfs_*() helpers to struct mnt_idmap 2023-01-18 17:51:45 +01:00
internal.h cachefiles: make on-demand request distribution fairer 2022-08-31 16:41:10 +01:00
io.c cachefiles: use kiocb_{start,end}_write() helpers 2023-08-21 17:27:27 +02:00
Kconfig cachefiles: notify the user daemon when looking up cookie 2022-05-18 00:11:17 +08:00
key.c cachefiles: Implement key to filename encoding 2022-01-07 13:42:16 +00:00
main.c cachefiles: Implement object lifecycle funcs 2022-01-07 13:42:08 +00:00
Makefile cachefiles: notify the user daemon when looking up cookie 2022-05-18 00:11:17 +08:00
namei.c rename(): avoid a deadlock in the case of parents having no common ancestor 2023-11-25 02:54:14 -05:00
ondemand.c cachefiles: make on-demand request distribution fairer 2022-08-31 16:41:10 +01:00
security.c cachefiles: Add security derivation 2022-01-07 13:41:14 +00:00
volume.c fscache, cachefiles: Store the volume coherency data 2022-01-07 13:43:03 +00:00
xattr.c fs: port ->permission() to pass mnt_idmap 2023-01-19 09:24:28 +01:00