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-rw-r--r--fs/kernfs/dir.c45
-rw-r--r--fs/kernfs/mount.c11
2 files changed, 10 insertions, 46 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 7d4af6cea2a6..798f0f03b62b 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -508,10 +508,6 @@ void kernfs_put(struct kernfs_node *kn)
struct kernfs_node *parent;
struct kernfs_root *root;
- /*
- * kernfs_node is freed with ->count 0, kernfs_find_and_get_node_by_ino
- * depends on this to filter reused stale node
- */
if (!kn || !atomic_dec_and_test(&kn->count))
return;
root = kernfs_root(kn);
@@ -646,11 +642,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
kn->id.ino = ret;
kn->id.generation = gen;
- /*
- * set ino first. This RELEASE is paired with atomic_inc_not_zero in
- * kernfs_find_and_get_node_by_ino
- */
- atomic_set_release(&kn->count, 1);
+ atomic_set(&kn->count, 1);
atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
RB_CLEAR_NODE(&kn->rb);
@@ -716,38 +708,19 @@ struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root,
{
struct kernfs_node *kn;
- rcu_read_lock();
+ spin_lock(&kernfs_idr_lock);
+
kn = idr_find(&root->ino_idr, ino);
if (!kn)
- goto out;
+ goto err_unlock;
- /*
- * Since kernfs_node is freed in RCU, it's possible an old node for ino
- * is freed, but reused before RCU grace period. But a freed node (see
- * kernfs_put) or an incompletedly initialized node (see
- * __kernfs_new_node) should have 'count' 0. We can use this fact to
- * filter out such node.
- */
- if (!atomic_inc_not_zero(&kn->count)) {
- kn = NULL;
- goto out;
- }
-
- /*
- * The node could be a new node or a reused node. If it's a new node,
- * we are ok. If it's reused because of RCU (because of
- * SLAB_TYPESAFE_BY_RCU), the __kernfs_new_node always sets its 'ino'
- * before 'count'. So if 'count' is uptodate, 'ino' should be uptodate,
- * hence we can use 'ino' to filter stale node.
- */
- if (kn->id.ino != ino)
- goto out;
- rcu_read_unlock();
+ if (unlikely(!atomic_inc_not_zero(&kn->count)))
+ goto err_unlock;
+ spin_unlock(&kernfs_idr_lock);
return kn;
-out:
- rcu_read_unlock();
- kernfs_put(kn);
+err_unlock:
+ spin_unlock(&kernfs_idr_lock);
return NULL;
}
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index 6c12fac2c287..067b7c380056 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -363,18 +363,9 @@ void kernfs_kill_sb(struct super_block *sb)
void __init kernfs_init(void)
{
-
- /*
- * the slab is freed in RCU context, so kernfs_find_and_get_node_by_ino
- * can access the slab lock free. This could introduce stale nodes,
- * please see how kernfs_find_and_get_node_by_ino filters out stale
- * nodes.
- */
kernfs_node_cache = kmem_cache_create("kernfs_node_cache",
sizeof(struct kernfs_node),
- 0,
- SLAB_PANIC | SLAB_TYPESAFE_BY_RCU,
- NULL);
+ 0, SLAB_PANIC, NULL);
/* Creates slab cache for kernfs inode attributes */
kernfs_iattrs_cache = kmem_cache_create("kernfs_iattrs_cache",