From 7a7f4cecbb6937d496ca6abf14450bf9e475a77e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=A0=E8=BF=9C=E6=B5=A9?= <bluefoxah@gmail.com>
Date: Mon, 11 Apr 2016 18:17:22 +0800
Subject: [PATCH] [MOD] fix a bug.if node is nil will get an panic.

---
 go/topology/node.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/go/topology/node.go b/go/topology/node.go
index 3b6d55ce9..f48f18236 100644
--- a/go/topology/node.go
+++ b/go/topology/node.go
@@ -211,8 +211,8 @@ func (n *NodeImpl) LinkChildNode(node Node) {
 
 func (n *NodeImpl) UnlinkChildNode(nodeId NodeId) {
 	node := n.children[nodeId]
-	node.SetParent(nil)
 	if node != nil {
+		node.SetParent(nil)
 		delete(n.children, node.Id())
 		n.UpAdjustVolumeCountDelta(-node.GetVolumeCount())
 		n.UpAdjustActiveVolumeCountDelta(-node.GetActiveVolumeCount())