SUNRPC: Split another new rpcbind retry error code from EACCES

Add more new error code processing to the kernel's rpcbind client
and to call_bind_status() to distinguish two cases:

Case 1: the remote has replied that the program/version tuple is not
registered (returns EACCES)

Case 2: retry with a lesser rpcbind version (rpcb now returns EPFNOSUPPORT)

This change allows more specific error processing for each of these two
cases.  We now fail case 2 instead of retrying... it's a server
configuration error not to support even rpcbind version 2.  And don't
expose this new error code to user land -- convert it to EIO before
failing the RPC.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/clnt.c

@@ -940,7 +940,7 @@ call_bind(struct rpc_task *task)
 static void
 call_bind_status(struct rpc_task *task)
 {
-	int status = -EACCES;
+	int status = -EIO;
 
 	if (task->tk_status >= 0) {
 		dprint_status(task);
@@ -966,6 +966,7 @@ call_bind_status(struct rpc_task *task)
 				task->tk_pid);
 		goto retry_timeout;
 	case -EPFNOSUPPORT:
+		/* server doesn't support any rpcbind version we know of */
 		dprintk("RPC: %5u remote rpcbind service unavailable\n",
 				task->tk_pid);
 		break;
@@ -978,7 +979,6 @@ call_bind_status(struct rpc_task *task)
 	default:
 		dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 				task->tk_pid, -task->tk_status);
-		status = -EIO;
 	}
 
 	rpc_exit(task, status);

net/sunrpc/rpcb_clnt.c

@@ -377,7 +377,7 @@ void rpcb_getport_async(struct rpc_task *task)
 	}
 	if (info[xprt->bind_index].rpc_proc == NULL) {
 		xprt->bind_index = 0;
-		status = -EACCES;	/* tell caller to try again later */
+		status = -EPFNOSUPPORT;
 		dprintk("RPC: %5u %s: no more getport versions available\n",
 			task->tk_pid, __FUNCTION__);
 		goto bailout_nofree;