SUNRPC: Ensure we close the socket on EPIPE errors too...

As long as one task is holding the socket lock, then calls to
xprt_force_disconnect(xprt) will not succeed in shutting down the socket.
In particular, this would mean that a server initiated shutdown will not
succeed until the lock is relinquished.
In order to avoid the deadlock, we should ensure that xs_tcp_send_request()
closes the socket on EPIPE errors too.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/xprtsock.c

@@ -726,10 +726,10 @@ static int xs_tcp_send_request(struct rpc_task *task)
 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
 			-status);
 	case -ECONNRESET:
+	case -EPIPE:
 		xs_tcp_shutdown(xprt);
 	case -ECONNREFUSED:
 	case -ENOTCONN:
-	case -EPIPE:
 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
 	}
 out: