diff options
| author | NeilBrown <neil@brown.name> | 2026-02-25 09:16:58 +1100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-03-09 09:43:03 +0100 |
| commit | 56c8fd738ed86667daa13c8a28fd1074f8a22cb7 (patch) | |
| tree | 54ec4289d3d4368997ad44cba225ff2f8fa9c135 | |
| parent | 8348278650bca7a51c274bdf898aa9a73ce4b67f (diff) | |
ovl: use is_subdir() for testing if one thing is a subdir of another
Rather than using lock_rename(), use the more obvious is_subdir() for
ensuring that neither upper nor workdir contain the other.
Also be explicit in the comment that the two directories cannot be the
same.
As this is a point-it-time sanity check and does not provide any
on-going guarantees, the removal of locking does not introduce any
interesting races.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20260224222542.3458677-14-neilb@ownmail.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | fs/overlayfs/super.c | 15 |
1 files changed, 5 insertions, 10 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 109643930b9f..58adefb1c5b8 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -451,18 +451,13 @@ static int ovl_lower_dir(const char *name, const struct path *path, return 0; } -/* Workdir should not be subdir of upperdir and vice versa */ +/* + * Workdir should not be subdir of upperdir and vice versa, and + * they should not be the same. + */ static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) { - bool ok = false; - - if (workdir != upperdir) { - struct dentry *trap = lock_rename(workdir, upperdir); - if (!IS_ERR(trap)) - unlock_rename(workdir, upperdir); - ok = (trap == NULL); - } - return ok; + return !is_subdir(workdir, upperdir) && !is_subdir(upperdir, workdir); } static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, |