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: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 3ae5604..8773b43 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1120,7 +1120,8 @@
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 @@
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);
}
}
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index a0646a3..75d748e 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -606,6 +606,34 @@
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 @@
} 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);
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 4a567a9..63d79e3 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1142,6 +1142,7 @@
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 @@
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