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 fda9e726f1cc1f4180edb168c061ec8efa3f6f70..76887d60f0c0f7adff0a75054514c240a5403b62 100644 (file)
--- 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 079f06fe2c5d7c25bf5e366e0ee15ea3bc73a73a..166f8c1680d1e4f82a575354768397b51e2e9d87 100644 (file)
--- 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;