HDFS-5666. Fix inconsistent synchronization in BPOfferService (jxiang via cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1551302 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -381,6 +381,8 @@ Release 2.3.0 - UNRELEASED
 
     HDFS-4201. NPE in BPServiceActor#sendHeartBeat. (jxiang via cmccabe)
 
+    HDFS-5666. Fix inconsistent synchronization in BPOfferService (jxiang via cmccabe)
+
 Release 2.2.0 - 2013-10-13
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BPOfferService.java

@@ -146,7 +146,7 @@ class BPOfferService {
     return false;
   }
   
-  String getBlockPoolId() {
+  synchronized String getBlockPoolId() {
     if (bpNSInfo != null) {
       return bpNSInfo.getBlockPoolID();
     } else {
@@ -161,7 +161,7 @@ class BPOfferService {
   }
   
   @Override
-  public String toString() {
+  public synchronized String toString() {
     if (bpNSInfo == null) {
       // If we haven't yet connected to our NN, we don't yet know our
       // own block pool ID.