diff options
Diffstat (limited to 'fs/kernfs/dir.c')
| -rw-r--r-- | fs/kernfs/dir.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 6acd9c3d4cff..77d7a3a28057 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -31,10 +31,15 @@ static DEFINE_SPINLOCK(kernfs_idr_lock); /* root->ino_idr */ #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) +static bool __kernfs_active(struct kernfs_node *kn) +{ + return atomic_read(&kn->active) >= 0; +} + static bool kernfs_active(struct kernfs_node *kn) { lockdep_assert_held(&kernfs_root(kn)->kernfs_rwsem); - return atomic_read(&kn->active) >= 0; + return __kernfs_active(kn); } static bool kernfs_lockdep(struct kernfs_node *kn) @@ -705,7 +710,12 @@ struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root, goto err_unlock; } - if (unlikely(!kernfs_active(kn) || !atomic_inc_not_zero(&kn->count))) + /* + * We should fail if @kn has never been activated and guarantee success + * if the caller knows that @kn is active. Both can be achieved by + * __kernfs_active() which tests @kn->active without kernfs_rwsem. + */ + if (unlikely(!__kernfs_active(kn) || !atomic_inc_not_zero(&kn->count))) goto err_unlock; spin_unlock(&kernfs_idr_lock); |