diff options
Diffstat (limited to 'fs/kernfs/dir.c')
| -rw-r--r-- | fs/kernfs/dir.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 770d687ee9f3..37dd6408f5f6 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -149,12 +149,25 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) if (unlikely(!kn)) return NULL; - if (!atomic_inc_unless_negative(&kn->active)) - return NULL; - if (kernfs_lockdep(kn)) rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); - return kn; + + /* + * Try to obtain an active ref. If @kn is deactivated, we block + * till either it's reactivated or killed. + */ + do { + if (atomic_inc_unless_negative(&kn->active)) + return kn; + + wait_event(kernfs_root(kn)->deactivate_waitq, + atomic_read(&kn->active) >= 0 || + RB_EMPTY_NODE(&kn->rb)); + } while (!RB_EMPTY_NODE(&kn->rb)); + + if (kernfs_lockdep(kn)) + rwsem_release(&kn->dep_map, 1, _RET_IP_); + return NULL; } /** @@ -786,6 +799,7 @@ static void __kernfs_deactivate(struct kernfs_node *kn) static void __kernfs_remove(struct kernfs_node *kn) { + struct kernfs_root *root = kernfs_root(kn); struct kernfs_node *pos; lockdep_assert_held(&kernfs_mutex); @@ -837,6 +851,9 @@ static void __kernfs_remove(struct kernfs_node *kn) kernfs_put(pos); } while (pos != kn); + + /* some nodes killed, kick get_active waiters */ + wake_up_all(&root->deactivate_waitq); } /** |