HDFS-5806. Balancer should set soTimeout to avoid indefinite hangs. Contributed by Nathan Roberts.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1560549 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -295,6 +295,9 @@ Release 2.4.0 - UNRELEASED
     HDFS-5748. Too much information shown in the dfs health page.
     (Haohui Mai via brandonli)
 
+    HDFS-5806. Balancer should set SoTimeout to avoid indefinite hangs.
+    (Nathan Roberts via Andrew Wang)
+
   BREAKDOWN OF HDFS-2832 SUBTASKS AND RELATED JIRAS
 
     HDFS-4985. Add storage type to the protocol and expose it in block report

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java

@@ -337,6 +337,7 @@ public class Balancer {
         sock.connect(
             NetUtils.createSocketAddr(target.datanode.getXferAddr()),
             HdfsServerConstants.READ_TIMEOUT);
+        sock.setSoTimeout(HdfsServerConstants.READ_TIMEOUT);
         sock.setKeepAlive(true);
         
         OutputStream unbufOut = sock.getOutputStream();