diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java
index e9fb7f342f..70186e2552 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java
@@ -207,8 +207,10 @@ private DatanodeStorageInfo[] chooseTarget(int numOfReplicas,
 
     final List<DatanodeStorageInfo> results = new ArrayList<DatanodeStorageInfo>(chosenStorage);
     for (DatanodeStorageInfo storage : chosenStorage) {
-      // add localMachine and related nodes to excludedNodes
-      addToExcludedNodes(storage.getDatanodeDescriptor(), excludedNodes);
+      if(storage!=null){
+        // add localMachine and related nodes to excludedNodes
+        addToExcludedNodes(storage.getDatanodeDescriptor(), excludedNodes);
+      }
     }
 
     boolean avoidStaleNodes = (stats != null
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
index bfa0ee2cb0..0057d770f3 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
@@ -3165,7 +3165,11 @@ public Object performTask() throws IOException {
 
             //find datanode storages
             final DatanodeManager dm = blockManager.getDatanodeManager();
-            chosen = Arrays.asList(dm.getDatanodeStorageInfos(existings, storageIDs));
+            if(existings.length!=0){
+              chosen = Arrays.asList(dm.getDatanodeStorageInfos(existings, storageIDs));
+            } else {
+              chosen = Collections.<DatanodeStorageInfo>emptyList();
+            }
 
             // choose new datanodes.
             final DatanodeStorageInfo[] targets = blockManager.chooseTarget4AdditionalDatanode(