From: Chuck Lever <chuck.lever@oracle.com>
Date: Fri, 16 Mar 2018 14:33:55 +0000 (-0400)
Subject: sunrpc: Add static trace point to report result of RPC ping
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a25a4cb3af177a4cf5621ffbf4fa89ae60c6d4d7;p=linux.git

sunrpc: Add static trace point to report result of RPC ping

This information can help track down local misconfiguration issues
as well as network partitions and unresponsive servers.

There are several ways to send a ping, and with transport multi-
plexing, the exact rpc_xprt that is used is sometimes not known by
the upper layer. The rpc_xprt pointer passed to the trace point
call also has to be RCU-safe.

I found a spot inside the client FSM where an rpc_xprt pointer is
always available and safe to use.

Suggested-by: Bill Baker <Bill.Baker@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index fda9e726f1cc1..76887d60f0c0f 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -453,6 +453,27 @@ DEFINE_EVENT(rpc_xprt_event, xprt_complete_rqst,
 	TP_PROTO(struct rpc_xprt *xprt, __be32 xid, int status),
 	TP_ARGS(xprt, xid, status));
 
+TRACE_EVENT(xprt_ping,
+	TP_PROTO(const struct rpc_xprt *xprt, int status),
+
+	TP_ARGS(xprt, status),
+
+	TP_STRUCT__entry(
+		__field(int, status)
+		__string(addr, xprt->address_strings[RPC_DISPLAY_ADDR])
+		__string(port, xprt->address_strings[RPC_DISPLAY_PORT])
+	),
+
+	TP_fast_assign(
+		__entry->status = status;
+		__assign_str(addr, xprt->address_strings[RPC_DISPLAY_ADDR]);
+		__assign_str(port, xprt->address_strings[RPC_DISPLAY_PORT]);
+	),
+
+	TP_printk("peer=[%s]:%s status=%d",
+			__get_str(addr), __get_str(port), __entry->status)
+);
+
 TRACE_EVENT(xs_tcp_data_ready,
 	TP_PROTO(struct rpc_xprt *xprt, int err, unsigned int total),
 
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 079f06fe2c5d7..166f8c1680d1e 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -2014,6 +2014,9 @@ call_transmit_status(struct rpc_task *task)
 	case -EPERM:
 		if (RPC_IS_SOFTCONN(task)) {
 			xprt_end_transmit(task);
+			if (!task->tk_msg.rpc_proc->p_proc)
+				trace_xprt_ping(task->tk_xprt,
+						task->tk_status);
 			rpc_exit(task, task->tk_status);
 			break;
 		}
@@ -2112,6 +2115,9 @@ call_status(struct rpc_task *task)
 	struct rpc_rqst	*req = task->tk_rqstp;
 	int		status;
 
+	if (!task->tk_msg.rpc_proc->p_proc)
+		trace_xprt_ping(task->tk_xprt, task->tk_status);
+
 	if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
 		task->tk_status = req->rq_reply_bytes_recvd;