diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2025-02-23 20:04:30 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2025-06-11 13:34:51 -0400 |
| commit | a97dc087da06b69ae976765d59810ca705e8dae1 (patch) | |
| tree | 75f57b4f443ffcb910d89f979c2c4bf2c4d2208a | |
| parent | d9b13cdad80dc11d74408cf201939a946e9303a6 (diff) | |
simple_lookup(): just set DCACHE_DONTCACHE
No need to mess with ->d_op at all. Note that ->d_delete that always
returns 1 is equivalent to having DCACHE_DONTCACHE in ->d_flags.
Later the same thing will be placed into ->s_d_flags of the filesystems
where we want that behaviour for all dentries; then the check in
simple_lookup() will at least get unlikely() slapped on it.
NOTE: there are only two filesystems where
* simple_lookup() might be called
* default ->d_op is non-NULL
* its ->d_delete() doesn't always return 1
If not for those, we could have simple_lookup() just set DCACHE_DONTCACHE
without even looking at ->d_op. Filesystems in question are btrfs
and tracefs; both have ->d_delete() returning 1 on anything fed to
simple_lookup(), so both would be fine with simple_lookup() setting
DCACHE_DONTCACHE regardless of ->d_op.
IOW, we might want to drop the check for ->d_op in simple_lookup();
it's definitely a separate story, though.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/libfs.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/libfs.c b/fs/libfs.c index ab82de070310..19cc12651708 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -75,9 +75,11 @@ struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned { if (dentry->d_name.len > NAME_MAX) return ERR_PTR(-ENAMETOOLONG); - if (!dentry->d_op) - d_set_d_op(dentry, &simple_dentry_operations); - + if (!dentry->d_op && !(dentry->d_flags & DCACHE_DONTCACHE)) { + spin_lock(&dentry->d_lock); + dentry->d_flags |= DCACHE_DONTCACHE; + spin_unlock(&dentry->d_lock); + } if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir)) return NULL; |