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-rw-r--r--fs/kernfs/dir.c25
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);
}
/**