SUNRPC: Fix an infinite loop in call_refresh/call_refreshresult

If the rpcauth_refreshcred() call returns an error other than
EACCES, ENOMEM or ETIMEDOUT, we currently end up looping forever
between call_refresh and call_refreshresult.

The correct thing to do here is to exit on all errors except
EAGAIN and ETIMEDOUT, for which case we retry 3 times, then
return EACCES.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/clnt.c

@@ -989,20 +989,26 @@ call_refreshresult(struct rpc_task *task)
 	dprint_status(task);
 
 	task->tk_status = 0;
-	task->tk_action = call_allocate;
-	if (status >= 0 && rpcauth_uptodatecred(task))
-		return;
+	task->tk_action = call_refresh;
 	switch (status) {
-	case -EACCES:
-		rpc_exit(task, -EACCES);
-		return;
-	case -ENOMEM:
-		rpc_exit(task, -ENOMEM);
+	case 0:
+		if (rpcauth_uptodatecred(task))
+			task->tk_action = call_allocate;
 		return;
 	case -ETIMEDOUT:
 		rpc_delay(task, 3*HZ);
+	case -EAGAIN:
+		status = -EACCES;
+		if (!task->tk_cred_retry)
+			break;
+		task->tk_cred_retry--;
+		dprintk("RPC: %5u %s: retry refresh creds\n",
+				task->tk_pid, __func__);
+		return;
 	}
-	task->tk_action = call_refresh;
+	dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
+				task->tk_pid, __func__, status);
+	rpc_exit(task, status);
 }
 
 /*