NFS: Ensure we time out if a delegreturn does not complete

We can't allow delegreturn to hold up nfs4_evict_inode() forever,
since that can cause the memory shrinkers to block. This patch
therefore ensures that we eventually time out, and complete the
reclaim of the inode.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs4proc.c

@@ -6259,6 +6259,7 @@ static void nfs4_delegreturn_done(struct rpc_task *task, void *calldata)
 		/* Fallthrough */
 	case -NFS4ERR_BAD_STATEID:
 	case -NFS4ERR_STALE_STATEID:
+	case -ETIMEDOUT:
 		task->tk_status = 0;
 		break;
 	case -NFS4ERR_OLD_STATEID:
@@ -6349,7 +6350,7 @@ static int _nfs4_proc_delegreturn(struct inode *inode, const struct cred *cred,
 		.rpc_client = server->client,
 		.rpc_message = &msg,
 		.callback_ops = &nfs4_delegreturn_ops,
-		.flags = RPC_TASK_ASYNC,
+		.flags = RPC_TASK_ASYNC | RPC_TASK_TIMEOUT,
 	};
 	int status = 0;