Commit 7c1d71cf authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: Don't disconnect more than once if retransmitting NFSv4 requests 



NFSv4 requires us to ensure that we break the TCP connection before we're
allowed to retransmit a request. However in the case where we're
retransmitting several requests that have been sent on the same
connection, we need to ensure that we don't interfere with the attempt to
reconnect and/or break the connection again once it has been established.

We therefore introduce a 'connection' cookie that is bumped every time a
connection is broken. This allows requests to track if they need to force a
disconnection.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 636ac433

include/linux/sunrpc/xprt.h

+8 −0
Original line number Diff line number Diff line
@@ -86,6 +86,10 @@ struct rpc_rqst { 
	unsigned long		rq_majortimeo;	/* major timeout alarm */

	unsigned long		rq_timeout;	/* Current timeout value */

	unsigned int		rq_retries;	/* # of retries */

	unsigned int		rq_connect_cookie;

						/* A cookie used to track the

						   state of the transport

						   connection */

	

	/*

	 * Partial send handling
@@ -152,6 +156,9 @@ struct rpc_xprt { 
	unsigned long		connect_timeout,

				bind_timeout,

				reestablish_timeout;

	unsigned int		connect_cookie;	/* A cookie that gets bumped

						   every time the transport

						   is reconnected */



	/*

	 * Disconnection of idle transports
@@ -241,6 +248,7 @@ void xprt_complete_rqst(struct rpc_task *task, int copied); 
void			xprt_release_rqst_cong(struct rpc_task *task);

void			xprt_disconnect_done(struct rpc_xprt *xprt);

void			xprt_force_disconnect(struct rpc_xprt *xprt);

void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);



/*

 * Reserved bit positions in xprt->state

net/sunrpc/clnt.c

+4 −2
Original line number Diff line number Diff line
@@ -1120,7 +1120,8 @@ call_status(struct rpc_task *task) 
	case -ETIMEDOUT:

		task->tk_action = call_timeout;

		if (task->tk_client->cl_discrtry)

			xprt_force_disconnect(task->tk_xprt);

			xprt_conditional_disconnect(task->tk_xprt,

					req->rq_connect_cookie);

		break;

	case -ECONNREFUSED:

	case -ENOTCONN:
@@ -1245,7 +1246,8 @@ out_retry: 
	if (task->tk_rqstp == req) {

		req->rq_received = req->rq_rcv_buf.len = 0;

		if (task->tk_client->cl_discrtry)

			xprt_force_disconnect(task->tk_xprt);

			xprt_conditional_disconnect(task->tk_xprt,

					req->rq_connect_cookie);

	}

}

net/sunrpc/xprt.c

+29 −0
Original line number Diff line number Diff line
@@ -606,6 +606,34 @@ void xprt_force_disconnect(struct rpc_xprt *xprt) 
	spin_unlock_bh(&xprt->transport_lock);

}



/**

 * xprt_conditional_disconnect - force a transport to disconnect

 * @xprt: transport to disconnect

 * @cookie: 'connection cookie'

 *

 * This attempts to break the connection if and only if 'cookie' matches

 * the current transport 'connection cookie'. It ensures that we don't

 * try to break the connection more than once when we need to retransmit

 * a batch of RPC requests.

 *

 */

void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie)

{

	/* Don't race with the test_bit() in xprt_clear_locked() */

	spin_lock_bh(&xprt->transport_lock);

	if (cookie != xprt->connect_cookie)

		goto out;

	if (test_bit(XPRT_CLOSING, &xprt->state) || !xprt_connected(xprt))

		goto out;

	set_bit(XPRT_CLOSE_WAIT, &xprt->state);

	/* Try to schedule an autoclose RPC call */

	if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)

		queue_work(rpciod_workqueue, &xprt->task_cleanup);

	xprt_wake_pending_tasks(xprt, -ENOTCONN);

out:

	spin_unlock_bh(&xprt->transport_lock);

}



static void

xprt_init_autodisconnect(unsigned long data)

{
@@ -849,6 +877,7 @@ void xprt_transmit(struct rpc_task *task) 
	} else if (!req->rq_bytes_sent)

		return;



	req->rq_connect_cookie = xprt->connect_cookie;

	status = xprt->ops->send_request(task);

	if (status == 0) {

		dprintk("RPC: %5u xmit complete\n", task->tk_pid);

net/sunrpc/xprtsock.c

+2 −0
Original line number Diff line number Diff line
@@ -1142,6 +1142,7 @@ static void xs_tcp_state_change(struct sock *sk) 
		break;

	case TCP_FIN_WAIT1:

		/* The client initiated a shutdown of the socket */

		xprt->connect_cookie++;

		xprt->reestablish_timeout = 0;

		set_bit(XPRT_CLOSING, &xprt->state);

		smp_mb__before_clear_bit();
@@ -1154,6 +1155,7 @@ static void xs_tcp_state_change(struct sock *sk) 
		set_bit(XPRT_CLOSING, &xprt->state);

		xprt_force_disconnect(xprt);

	case TCP_SYN_SENT:

		xprt->connect_cookie++;

	case TCP_CLOSING:

		/*

		 * If the server closed down the connection, make sure that

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