diff --git a/weed/storage/store.go b/weed/storage/store.go
index 3562cde18..9ae9e9644 100644
--- a/weed/storage/store.go
+++ b/weed/storage/store.go
@@ -67,7 +67,7 @@ func (mn *MasterNodes) findMaster() (string, error) {
 				}
 				mn.nodes = append(masters, m)
 				mn.master = mn.nodes[rand.Intn(len(mn.nodes))]
-				glog.V(2).Infof("current master nodes is (nodes:%v, master:%s)", mn, mn.nodes, mn.master)
+				glog.V(2).Infof("current master nodes is (nodes:%v, master:%s)", mn.nodes, mn.master)
 				break
 			} else {
 				glog.V(4).Infof("Failed listing masters on %s: %v", m, e)
diff --git a/weed/storage/volume.go b/weed/storage/volume.go
index 8ec698fd4..9b358317a 100644
--- a/weed/storage/volume.go
+++ b/weed/storage/volume.go
@@ -38,7 +38,13 @@ func NewVolume(dirname string, collection string, id VolumeId, needleMapKind Nee
 func (v *Volume) String() string {
 	v.mutex.RLock()
 	defer v.mutex.RUnlock()
-	return fmt.Sprintf("Id:%v, dir:%s, Collection:%s, dataFile:%v, nm:%v, readOnly:%v", v.Id, v.dir, v.Collection, v.dataFile, v.nm, v.readOnly)
+	return fmt.Sprintf("Id:%v, dir:%s, Collection:%s, dataFile:%v, nm:%v, readOnly:%v",
+		v.Id,
+		v.dir,
+		v.Collection,
+		v.dataFile,
+		v.nm,
+		v.readOnly)
 }
 
 func loadVolumeWithoutIndex(dirname string, collection string, id VolumeId, needleMapKind NeedleMapType) (v *Volume, e error) {
diff --git a/weed/topology/data_node.go b/weed/topology/data_node.go
index 4798a3c38..0a0fec80e 100644
--- a/weed/topology/data_node.go
+++ b/weed/topology/data_node.go
@@ -34,7 +34,7 @@ func (dn *DataNode) String() string {
 	dn.mutex.RLock()
 	defer dn.mutex.RUnlock()
 	return fmt.Sprintf("Node:%s, volumes:%v, Ip:%s, Port:%d, PublicUrl:%s, Dead:%v",
-		dn.NodeImpl.String(),
+		dn.NodeImpl.toString(),
 		dn.volumes,
 		dn.Ip,
 		dn.Port,
diff --git a/weed/topology/node.go b/weed/topology/node.go
index f8de1a28a..40479f11f 100644
--- a/weed/topology/node.go
+++ b/weed/topology/node.go
@@ -132,11 +132,18 @@ func (n *NodeImpl) IsDataCenter() bool {
 	return n.nodeType == "DataCenter"
 }
 func (n *NodeImpl) String() string {
-	if n.Parent() != nil {
-		return n.Parent().String() + ":" + string(n.id)
+	n.mutex.RLock()
+	defer n.mutex.RUnlock()
+	return n.toString()
+}
+
+func (n *NodeImpl) toString() string {
+	if n.parent != nil {
+		return n.parent.String() + ":" + string(n.id)
 	}
 	return string(n.id)
 }
+
 func (n *NodeImpl) Id() NodeId {
 	return n.id
 }