[PATCH] RPC: proper soft timeout behavior for rpcbind

 Implement a best practice:  for soft mounts, an rpcbind timeout should
 cause an RPC request to fail.

 This also provides an FSM hook for retrying an rpcbind with a different
 rpcbind protocol version.  We'll use this later to try multiple rpcbind
 protocol versions when binding.  To enable this, expose the RPC error
 code returned during a portmap request to the FSM so it can make some
 decision about how to report, retry, or fail the request.

 Test-plan:
 Hundreds of passes with connectathon NFSv3 locking suite, on the client
 and server.

 Version: Thu, 11 Aug 2005 16:01:53 -0400

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index f17e615..2d3cf0a 100644 (file)
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -53,6 +53,7 @@ static void   call_allocate(struct rpc_task *task);
 static void    call_encode(struct rpc_task *task);
 static void    call_decode(struct rpc_task *task);
 static void    call_bind(struct rpc_task *task);
+static void    call_bind_status(struct rpc_task *task);
 static void    call_transmit(struct rpc_task *task);
 static void    call_status(struct rpc_task *task);
 static void    call_refresh(struct rpc_task *task);
@@ -734,43 +735,94 @@ static void
 call_bind(struct rpc_task *task)
 {
        struct rpc_clnt *clnt = task->tk_client;
-       struct rpc_xprt *xprt = clnt->cl_xprt;
-
-       dprintk("RPC: %4d call_bind xprt %p %s connected\n", task->tk_pid,
-                       xprt, (xprt_connected(xprt) ? "is" : "is not"));
 
-       task->tk_action = (xprt_connected(xprt)) ? call_transmit : call_connect;
+       dprintk("RPC: %4d call_bind (status %d)\n",
+                               task->tk_pid, task->tk_status);
 
+       task->tk_action = call_connect;
        if (!clnt->cl_port) {
-               task->tk_action = call_connect;
+               task->tk_action = call_bind_status;
                task->tk_timeout = RPC_CONNECT_TIMEOUT;
                rpc_getport(task, clnt);
        }
 }
 
 /*
- * 4a. Connect to the RPC server (TCP case)
+ * 4a. Sort out bind result
+ */
+static void
+call_bind_status(struct rpc_task *task)
+{
+       int status = -EACCES;
+
+       if (task->tk_status >= 0) {
+               dprintk("RPC: %4d call_bind_status (status %d)\n",
+                                       task->tk_pid, task->tk_status);
+               task->tk_status = 0;
+               task->tk_action = call_connect;
+               return;
+       }
+
+       switch (task->tk_status) {
+       case -EACCES:
+               dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
+                               task->tk_pid);
+               break;
+       case -ETIMEDOUT:
+               dprintk("RPC: %4d rpcbind request timed out\n",
+                               task->tk_pid);
+               if (RPC_IS_SOFT(task)) {
+                       status = -EIO;
+                       break;
+               }
+               goto retry_bind;
+       case -EPFNOSUPPORT:
+               dprintk("RPC: %4d remote rpcbind service unavailable\n",
+                               task->tk_pid);
+               break;
+       case -EPROTONOSUPPORT:
+               dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
+                               task->tk_pid);
+               break;
+       default:
+               dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
+                               task->tk_pid, -task->tk_status);
+               status = -EIO;
+               break;
+       }
+
+       rpc_exit(task, status);
+       return;
+
+retry_bind:
+       task->tk_status = 0;
+       task->tk_action = call_bind;
+       return;
+}
+
+/*
+ * 4b. Connect to the RPC server
  */
 static void
 call_connect(struct rpc_task *task)
 {
-       struct rpc_clnt *clnt = task->tk_client;
+       struct rpc_xprt *xprt = task->tk_xprt;
 
-       dprintk("RPC: %4d call_connect status %d\n",
-                               task->tk_pid, task->tk_status);
+       dprintk("RPC: %4d call_connect xprt %p %s connected\n",
+                       task->tk_pid, xprt,
+                       (xprt_connected(xprt) ? "is" : "is not"));
 
-       if (xprt_connected(clnt->cl_xprt)) {
-               task->tk_action = call_transmit;
-               return;
+       task->tk_action = call_transmit;
+       if (!xprt_connected(xprt)) {
+               task->tk_action = call_connect_status;
+               if (task->tk_status < 0)
+                       return;
+               xprt_connect(task);
        }
-       task->tk_action = call_connect_status;
-       if (task->tk_status < 0)
-               return;
-       xprt_connect(task);
 }
 
 /*
- * 4b. Sort out connect result
+ * 4c. Sort out connect result
  */
 static void
 call_connect_status(struct rpc_task *task)
@@ -778,6 +830,9 @@ call_connect_status(struct rpc_task *task)
        struct rpc_clnt *clnt = task->tk_client;
        int status = task->tk_status;
 
+       dprintk("RPC: %5u call_connect_status (status %d)\n", 
+                               task->tk_pid, task->tk_status);
+
        task->tk_status = 0;
        if (status >= 0) {
                clnt->cl_stats->netreconn++;
@@ -785,17 +840,19 @@ call_connect_status(struct rpc_task *task)
                return;
        }
 
-       /* Something failed: we may have to rebind */
+       /* Something failed: remote service port may have changed */
        if (clnt->cl_autobind)
                clnt->cl_port = 0;
+
        switch (status) {
        case -ENOTCONN:
        case -ETIMEDOUT:
        case -EAGAIN:
-               task->tk_action = (clnt->cl_port == 0) ? call_bind : call_connect;
+               task->tk_action = call_bind;
                break;
        default:
                rpc_exit(task, -EIO);
+               break;
        }
 }