NFSv4.1: Don't check delegations that are already marked as revoked

If the delegation has been marked as revoked, we don't have to test
it, because we should already have called FREE_STATEID on it.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Olek Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/nfs4proc.c

@@ -2423,6 +2423,11 @@ static void nfs41_check_delegation_stateid(struct nfs4_state *state)
 		rcu_read_unlock();
 		return;
 	}
+	if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
+		rcu_read_unlock();
+		nfs_finish_clear_delegation_stateid(state);
+		return;
+	}
 
 	nfs4_stateid_copy(&stateid, &delegation->stateid);
 	cred = get_rpccred(delegation->cred);