make RPC timeout behavior over TCP sockets behave more like reference
client implementations. reference behavior is to transmit the same
request three times at 60 second intervals; if there is no response, close
and reestablish the socket connection. we modify the Linux RPC client as
follows:
+ after a minor retransmit timeout, use the same timeout value when
retrying on a TCP socket rather than doubling the value
+ after a major retransmit timeout, close the socket and attempt
to reestablish a fresh TCP connection
note that today mount uses a 6 second timeout with 5 retries for NFS over
TCP by default; proper default behavior is 2 retries each with 60 second
timeouts. a separate patch for mount is pending.
against 2.5.47.
diff -ruN 10-connect3/include/linux/sunrpc/xprt.h 11-timeout/include/linux/sunrpc/xprt.h
--- 10-connect3/include/linux/sunrpc/xprt.h Tue Nov 12 16:18:57 2002
+++ 11-timeout/include/linux/sunrpc/xprt.h Tue Nov 12 17:06:16 2002
@@ -182,9 +182,10 @@
void xprt_reserve(struct rpc_task *);
void xprt_transmit(struct rpc_task *);
void xprt_receive(struct rpc_task *);
-int xprt_adjust_timeout(struct rpc_timeout *);
+void xprt_adjust_timeout(struct rpc_timeout *);
void xprt_release(struct rpc_task *);
void xprt_connect(struct rpc_task *);
+void xprt_disconnect(struct rpc_xprt *);
int xprt_clear_backlog(struct rpc_xprt *);
void xprt_sock_setbufsize(struct rpc_xprt *);
diff -ruN 10-connect3/net/sunrpc/clnt.c 11-timeout/net/sunrpc/clnt.c
--- 10-connect3/net/sunrpc/clnt.c Tue Nov 12 16:19:25 2002
+++ 11-timeout/net/sunrpc/clnt.c Tue Nov 12 17:13:24 2002
@@ -667,6 +667,9 @@
if (clnt->cl_autobind)
clnt->cl_port = 0;
task->tk_action = call_bind;
+ /* A disconnect can happen after only part of an RPC was
+ * sent on a TCP socket. send all of this request again */
+ req->rq_bytes_sent = 0;
break;
case -EAGAIN:
task->tk_action = call_transmit;
@@ -688,20 +691,34 @@
* 6a. Handle RPC timeout
* We do not release the request slot, so we keep using the
* same XID for all retransmits.
+ * For stream transports, shut down the transport socket when
+ * a request sees a major time out. When any request on this
+ * connection is retried, the FSM notices the socket has been
+ * shut down, and attempts to reconnect.
*/
static void
call_timeout(struct rpc_task *task)
{
struct rpc_clnt *clnt = task->tk_client;
- struct rpc_timeout *to = &task->tk_rqstp->rq_timeout;
+ struct rpc_xprt *xprt = clnt->cl_xprt;
+ struct rpc_rqst *req = task->tk_rqstp;
+ struct rpc_timeout *to = &req->rq_timeout;
- if (xprt_adjust_timeout(to)) {
- dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
+ if (!xprt->stream)
+ xprt_adjust_timeout(to);
+
+ if (to->to_retries--) {
+ dprintk("RPC: %4d call_timeout (minor, retries=%d)\n",
+ task->tk_pid, to->to_retries);
goto retry;
}
- to->to_retries = clnt->cl_timeout.to_retries;
+ to->to_retries = xprt->timeout.to_retries;
dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
+
+ if (xprt->stream)
+ xprt_disconnect(xprt);
+
if (clnt->cl_softrtry) {
if (clnt->cl_chatty && !task->tk_exit)
printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
@@ -710,15 +727,18 @@
return;
}
- if (clnt->cl_chatty && !(task->tk_flags & RPC_CALL_MAJORSEEN) && rpc_ntimeo(&clnt->cl_rtt) > 7) {
- task->tk_flags |= RPC_CALL_MAJORSEEN;
- printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
- clnt->cl_protname, clnt->cl_server);
+ if (clnt->cl_chatty && !(task->tk_flags & RPC_CALL_MAJORSEEN)) {
+ if (xprt->stream || (rpc_ntimeo(&clnt->cl_rtt) > 7)) {
+ task->tk_flags |= RPC_CALL_MAJORSEEN;
+ printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
+ clnt->cl_protname, clnt->cl_server);
+ }
}
if (clnt->cl_autobind)
clnt->cl_port = 0;
retry:
+ req->rq_bytes_sent = 0; /* send all of this request again */
clnt->cl_stats->rpcretrans++;
task->tk_action = call_bind;
task->tk_status = 0;
diff -ruN 10-connect3/net/sunrpc/xprt.c 11-timeout/net/sunrpc/xprt.c
--- 10-connect3/net/sunrpc/xprt.c Tue Nov 12 16:31:08 2002
+++ 11-timeout/net/sunrpc/xprt.c Tue Nov 12 17:06:16 2002
@@ -85,7 +85,6 @@
static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
static void do_xprt_transmit(struct rpc_task *);
static inline void do_xprt_reserve(struct rpc_task *);
-static void xprt_disconnect(struct rpc_xprt *);
static void xprt_conn_status(struct rpc_task *task);
static struct rpc_xprt * xprt_setup(int proto, struct sockaddr_in *ap,
struct rpc_timeout *to);
@@ -336,7 +335,7 @@
/*
* Adjust timeout values etc for next retransmit
*/
-int
+void
xprt_adjust_timeout(struct rpc_timeout *to)
{
if (to->to_retries > 0) {
@@ -362,7 +361,7 @@
}
pprintk("RPC: %lu %s\n", jiffies,
to->to_retries? "retrans" : "timeout");
- return to->to_retries-- > 0;
+ return;
}
/*
@@ -394,7 +393,7 @@
/*
* Mark a transport as disconnected
*/
-static void
+void
xprt_disconnect(struct rpc_xprt *xprt)
{
dprintk("RPC: disconnected transport %p\n", xprt);
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