svn merge -c 1243654 from trunk for HDFS-776.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1243657 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -26,6 +26,9 @@ Release 0.23.2 - UNRELEASED
 
     HDFS-2869. Fix an error in the webhdfs docs for the mkdir op (harsh)
 
+    HDFS-776.  Fix exception handling in Balancer.  (Uma Maheswara Rao G
+    via szetszwo)
+
 Release 0.23.1 - 2012-02-08 
 
   INCOMPATIBLE CHANGES

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

@@ -122,6 +122,10 @@ class NameNodeConnector {
     if (!isBlockTokenEnabled) {
       return BlockTokenSecretManager.DUMMY_TOKEN;
     } else {
+      if (!shouldRun) {
+        throw new IOException(
+            "Can not get access token. BlockKeyUpdater is not running");
+      }
       return blockTokenSecretManager.generateToken(null, eb,
           EnumSet.of(BlockTokenSecretManager.AccessMode.REPLACE,
           BlockTokenSecretManager.AccessMode.COPY));
@@ -217,16 +221,20 @@ class NameNodeConnector {
    */
   class BlockKeyUpdater implements Runnable {
     public void run() {
-      while (shouldRun) {
-        try {
-          blockTokenSecretManager.setKeys(namenode.getBlockKeys());
-        } catch (Exception e) {
-          LOG.error("Failed to set keys", e);
-        }
-        try {
+      try {
+        while (shouldRun) {
+          try {
+            blockTokenSecretManager.setKeys(namenode.getBlockKeys());
+          } catch (IOException e) {
+            LOG.error("Failed to set keys", e);
+          }
           Thread.sleep(keyUpdaterInterval);
-        } catch (InterruptedException ie) {
         }
+      } catch (InterruptedException e) {
+        LOG.info("InterruptedException in block key updater thread", e);
+      } catch (Throwable e) {
+        LOG.error("Exception in block key updater thread", e);
+        shouldRun = false;
       }
     }
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancerWithMultipleNameNodes.java

@@ -57,14 +57,12 @@ public class TestBalancerWithMultipleNameNodes {
     ((Log4JLogger)NameNode.stateChangeLog).getLogger().setLevel(Level.OFF);
     ((Log4JLogger)LeaseManager.LOG).getLogger().setLevel(Level.OFF);
     ((Log4JLogger)LogFactory.getLog(FSNamesystem.class)).getLogger().setLevel(Level.OFF);
-//    ((Log4JLogger)DataNode.LOG).getLogger().setLevel(Level.OFF);
   }
 
   
   private static final long CAPACITY = 500L;
   private static final String RACK0 = "/rack0";
   private static final String RACK1 = "/rack1";
-  private static final String RACK2 = "/rack2";
 
   private static final String FILE_NAME = "/tmp.txt";
   private static final Path FILE_PATH = new Path(FILE_NAME);