From bccdfeee0aaef9cb98d09ee39909b63fdcbeeafc Mon Sep 17 00:00:00 2001
From: Wei-Chiu Chuang <weichiu@apache.org>
Date: Mon, 4 Jun 2018 07:02:05 -0700
Subject: [PATCH] HDFS-13155. BlockPlacementPolicyDefault.chooseTargetInOrder
 Not Checking Return Value for NULL. Contributed by Zsolt Venczel.

---
 .../blockmanagement/BlockPlacementPolicyDefault.java   | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

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 518e62c6b2e..c94232fbcb1 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
@@ -485,9 +485,13 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
                                  throws NotEnoughReplicasException {
     final int numOfResults = results.size();
     if (numOfResults == 0) {
-      writer = chooseLocalStorage(writer, excludedNodes, blocksize,
-          maxNodesPerRack, results, avoidStaleNodes, storageTypes, true)
-          .getDatanodeDescriptor();
+      DatanodeStorageInfo storageInfo = chooseLocalStorage(writer,
+          excludedNodes, blocksize, maxNodesPerRack, results, avoidStaleNodes,
+          storageTypes, true);
+
+      writer = (storageInfo != null) ? storageInfo.getDatanodeDescriptor()
+                                     : null;
+
       if (--numOfReplicas == 0) {
         return writer;
       }