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>
This commit is contained in:
Trond Myklebust 2012-04-21 12:31:05 -04:00
parent 95b72eb0bd
commit c77365c963

View file

@ -435,13 +435,17 @@ nfs4_alloc_state_owner(struct nfs_server *server,
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);
}
}