NFSv4: Ensure that we don't drop a state owner more than once
Retest the RB_EMPTY_NODE() condition under the spin lock
to ensure that we don't call rb_erase() more than once on the
same state owner.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 3b07f09..b300fb8 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -435,13 +435,17 @@
static void
nfs4_drop_state_owner(struct nfs4_state_owner *sp)
{
- if (!RB_EMPTY_NODE(&sp->so_server_node)) {
+ struct rb_node *rb_node = &sp->so_server_node;
+
+ if (!RB_EMPTY_NODE(rb_node)) {
struct nfs_server *server = sp->so_server;
struct nfs_client *clp = server->nfs_client;
spin_lock(&clp->cl_lock);
- rb_erase(&sp->so_server_node, &server->state_owners);
- RB_CLEAR_NODE(&sp->so_server_node);
+ if (!RB_EMPTY_NODE(rb_node)) {
+ rb_erase(rb_node, &server->state_owners);
+ RB_CLEAR_NODE(rb_node);
+ }
spin_unlock(&clp->cl_lock);
}
}