diff options
| -rw-r--r-- | fs/kernfs/dir.c | 45 | ||||
| -rw-r--r-- | fs/kernfs/mount.c | 11 |
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", |