HDFS-5747. Merging r1557289 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1557291 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -260,7 +260,9 @@ Release 2.4.0 - UNRELEASED
     HDFS-5756. hadoopRzOptionsSetByteBufferPool does not accept NULL argument,
     contrary to docs. (cmccabe via wang)
 
-BREAKDOWN OF HDFS-2832 SUBTASKS AND RELATED JIRAS
+    HDFS-5747. Fix NPEs in BlockManager. (Arpit Agarwal)
+
+  BREAKDOWN OF HDFS-2832 SUBTASKS AND RELATED JIRAS
 
     HDFS-4985. Add storage type to the protocol and expose it in block report
     and block locations. (Arpit Agarwal)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockInfoUnderConstruction.java

@@ -324,12 +324,14 @@ public class BlockInfoUnderConstruction extends BlockInfo {
     Iterator<ReplicaUnderConstruction> it = replicas.iterator();
     while (it.hasNext()) {
       ReplicaUnderConstruction r = it.next();
-      if(r.getExpectedStorageLocation() == storage) {
+      DatanodeStorageInfo expectedLocation = r.getExpectedStorageLocation();
+      if(expectedLocation == storage) {
         // Record the gen stamp from the report
         r.setGenerationStamp(block.getGenerationStamp());
         return;
-      } else if (r.getExpectedStorageLocation().getDatanodeDescriptor() ==
-          storage.getDatanodeDescriptor()) {
+      } else if (expectedLocation != null &&
+                 expectedLocation.getDatanodeDescriptor() ==
+                     storage.getDatanodeDescriptor()) {
 
         // The Datanode reported that the block is on a different storage
         // than the one chosen by BlockPlacementPolicy. This can occur as

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java

@@ -549,8 +549,8 @@ public class NameNode implements NameNodeStatusMXBean {
   }
   
   private void stopCommonServices() {
-    if(namesystem != null) namesystem.close();
     if(rpcServer != null) rpcServer.stop();
+    if(namesystem != null) namesystem.close();
     if (pauseMonitor != null) pauseMonitor.stop();
     if (plugins != null) {
       for (ServicePlugin p : plugins) {