1 files changed, 11 insertions, 0 deletions

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 82db7b323b83..fe9bdb4a220c 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -795,6 +795,17 @@ static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
 
         dprintk("lockd: GRANT_MSG RPC callback\n");
 
+        /* if the block is not on a list at this point then it has
+         * been invalidated. Don't try to requeue it.
+         *
+         * FIXME: it's possible that the block is removed from the list
+         * after this check but before the nlmsvc_insert_block. In that
+         * case it will be added back. Perhaps we need better locking
+         * for nlm_blocked?
+         */
+        if (list_empty(&block->b_list))
+                return;
+
         /* Technically, we should down the file semaphore here. Since we
          * move the block towards the head of the queue only, no harm
          * can be done, though. */