HDFS-9371. Code cleanup for DatanodeManager. Contributed by Jing Zhao.

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

@@ -899,6 +899,8 @@ Release 2.9.0 - UNRELEASED
     HDFS-9281. Change TestDeleteBlockPool to not explicitly use File to check
     block pool existence. (lei)
 
+    HDFS-9371. Code cleanup for DatanodeManager. (jing9)
+
   OPTIMIZATIONS
 
   BUG FIXES

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

@@ -132,6 +132,9 @@ public class BlockManager implements BlockStatsMXBean {
   private final HeartbeatManager heartbeatManager;
   private final BlockTokenSecretManager blockTokenSecretManager;
 
+  // Block pool ID used by this namenode
+  private String blockPoolId;
+
   private final PendingDataNodeMessages pendingDNMessages =
     new PendingDataNodeMessages();
 
@@ -462,11 +465,16 @@ public class BlockManager implements BlockStatsMXBean {
   }
 
   public void setBlockPoolId(String blockPoolId) {
+    this.blockPoolId = blockPoolId;
     if (isBlockTokenEnabled()) {
       blockTokenSecretManager.setBlockPoolId(blockPoolId);
     }
   }
 
+  public String getBlockPoolId() {
+    return blockPoolId;
+  }
+
   public BlockStoragePolicySuite getStoragePolicySuite() {
     return storagePolicySuite;
   }
@@ -1228,18 +1236,6 @@ public class BlockManager implements BlockStatsMXBean {
         ((BlockInfoStriped) storedBlock).getBlockOnStorage(storage) : storedBlock;
   }
 
-  /**
-   * Remove all block invalidation tasks under this datanode UUID;
-   * used when a datanode registers with a new UUID and the old one
-   * is wiped.
-   */
-  void removeFromInvalidates(final DatanodeInfo datanode) {
-    if (!isPopulatingReplQueues()) {
-      return;
-    }
-    invalidateBlocks.remove(datanode);
-  }
-
   /**
    * Mark the block belonging to datanode as corrupt
    * @param blk Block to be marked as corrupt

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

@@ -290,11 +290,11 @@ public class DatanodeDescriptor extends DatanodeInfo {
     this.isAlive = isAlive;
   }
 
-  public boolean needKeyUpdate() {
+  public synchronized boolean needKeyUpdate() {
     return needKeyUpdate;
   }
 
-  public void setNeedKeyUpdate(boolean needKeyUpdate) {
+  public synchronized void setNeedKeyUpdate(boolean needKeyUpdate) {
     this.needKeyUpdate = needKeyUpdate;
   }
 
@@ -868,14 +868,14 @@ public class DatanodeDescriptor extends DatanodeInfo {
   /**
    * @return balancer bandwidth in bytes per second for this datanode
    */
-  public long getBalancerBandwidth() {
+  public synchronized long getBalancerBandwidth() {
     return this.bandwidth;
   }
 
   /**
    * @param bandwidth balancer bandwidth in bytes per second for this datanode
    */
-  public void setBalancerBandwidth(long bandwidth) {
+  public synchronized void setBalancerBandwidth(long bandwidth) {
     this.bandwidth = bandwidth;
   }
 

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

@@ -17,6 +17,7 @@
  */
 package org.apache.hadoop.hdfs.server.blockmanagement;
 
+import static org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol.DNA_ERASURE_CODING_RECOVERY;
 import static org.apache.hadoop.util.Time.monotonicNow;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -162,7 +163,7 @@ public class DatanodeManager {
    * during rolling upgrades.
    * Software version -> Number of datanodes with this version
    */
-  private HashMap<String, Integer> datanodesSoftwareVersions =
+  private final HashMap<String, Integer> datanodesSoftwareVersions =
     new HashMap<>(4, 0.75f);
   
   /**
@@ -352,15 +353,9 @@ public class DatanodeManager {
   }
 
   private boolean isInactive(DatanodeInfo datanode) {
-    if (datanode.isDecommissioned()) {
+    return datanode.isDecommissioned() ||
-      return true;
+        (avoidStaleDataNodesForRead && datanode.isStale(staleInterval));
-    }
 
-    if (avoidStaleDataNodesForRead) {
-      return datanode.isStale(staleInterval);
-    }
-      
-    return false;
   }
   
   /** Sort the located blocks by the distance to the target host. */
@@ -479,9 +474,10 @@ public class DatanodeManager {
     if (datanodeUuid == null) {
       return null;
     }
-
+    synchronized (this) {
       return datanodeMap.get(datanodeUuid);
     }
+  }
 
   /**
    * Get data node by datanode ID.
@@ -490,8 +486,8 @@ public class DatanodeManager {
    * @return DatanodeDescriptor or null if the node is not found.
    * @throws UnregisteredNodeException
    */
-  public DatanodeDescriptor getDatanode(DatanodeID nodeID
+  public DatanodeDescriptor getDatanode(DatanodeID nodeID)
-      ) throws UnregisteredNodeException {
+      throws UnregisteredNodeException {
     final DatanodeDescriptor node = getDatanode(nodeID.getDatanodeUuid());
     if (node == null) 
       return null;
@@ -535,15 +531,15 @@ public class DatanodeManager {
 
   /** Prints information about all datanodes. */
   void datanodeDump(final PrintWriter out) {
-    synchronized (datanodeMap) {
+    final Map<String,DatanodeDescriptor> sortedDatanodeMap;
-      Map<String,DatanodeDescriptor> sortedDatanodeMap =
+    synchronized (this) {
-          new TreeMap<>(datanodeMap);
+      sortedDatanodeMap = new TreeMap<>(datanodeMap);
-      out.println("Metasave: Number of datanodes: " + datanodeMap.size());
+    }
+    out.println("Metasave: Number of datanodes: " + sortedDatanodeMap.size());
     for (DatanodeDescriptor node : sortedDatanodeMap.values()) {
       out.println(node.dumpDatanode());
     }
   }
-  }
 
   /**
    * Remove a datanode descriptor.
@@ -567,8 +563,8 @@ public class DatanodeManager {
    * Remove a datanode
    * @throws UnregisteredNodeException 
    */
-  public void removeDatanode(final DatanodeID node
+  public void removeDatanode(final DatanodeID node)
-      ) throws UnregisteredNodeException {
+      throws UnregisteredNodeException {
     namesystem.writeLock();
     try {
       final DatanodeDescriptor descriptor = getDatanode(node);
@@ -585,7 +581,6 @@ public class DatanodeManager {
 
   /** Remove a dead datanode. */
   void removeDeadDatanode(final DatanodeID nodeID) {
-      synchronized(datanodeMap) {
     DatanodeDescriptor d;
     try {
       d = getDatanode(nodeID);
@@ -598,7 +593,6 @@ public class DatanodeManager {
       removeDatanode(d);
     }
   }
-  }
 
   /** Is the datanode dead? */
   boolean isDatanodeDead(DatanodeDescriptor node) {
@@ -611,14 +605,13 @@ public class DatanodeManager {
     // To keep host2DatanodeMap consistent with datanodeMap,
     // remove  from host2DatanodeMap the datanodeDescriptor removed
     // from datanodeMap before adding node to host2DatanodeMap.
-    synchronized(datanodeMap) {
+    synchronized(this) {
       host2DatanodeMap.remove(datanodeMap.put(node.getDatanodeUuid(), node));
     }
 
     networktopology.add(node); // may throw InvalidTopologyException
     host2DatanodeMap.add(node);
     checkIfClusterIsNowMultiRack(node);
-    blockManager.getBlockReportLeaseManager().register(node);
 
     if (LOG.isDebugEnabled()) {
       LOG.debug(getClass().getSimpleName() + ".addDatanode: "
@@ -629,11 +622,9 @@ public class DatanodeManager {
   /** Physically remove node from datanodeMap. */
   private void wipeDatanode(final DatanodeID node) {
     final String key = node.getDatanodeUuid();
-    synchronized (datanodeMap) {
+    synchronized (this) {
       host2DatanodeMap.remove(datanodeMap.remove(key));
     }
-    // Also remove all block invalidation tasks under this node
-    blockManager.removeFromInvalidates(new DatanodeInfo(node));
     if (LOG.isDebugEnabled()) {
       LOG.debug(getClass().getSimpleName() + ".wipeDatanode("
           + node + "): storage " + key 
@@ -645,7 +636,7 @@ public class DatanodeManager {
     if (version == null) {
       return;
     }
-    synchronized(datanodeMap) {
+    synchronized(this) {
       Integer count = this.datanodesSoftwareVersions.get(version);
       count = count == null ? 1 : count + 1;
       this.datanodesSoftwareVersions.put(version, count);
@@ -656,7 +647,7 @@ public class DatanodeManager {
     if (version == null) {
       return;
     }
-    synchronized(datanodeMap) {
+    synchronized(this) {
       Integer count = this.datanodesSoftwareVersions.get(version);
       if(count != null) {
         if(count > 1) {
@@ -674,24 +665,22 @@ public class DatanodeManager {
   }
 
   private void countSoftwareVersions() {
-    synchronized(datanodeMap) {
+    synchronized(this) {
-      HashMap<String, Integer> versionCount = new HashMap<>();
+      datanodesSoftwareVersions.clear();
       for(DatanodeDescriptor dn: datanodeMap.values()) {
         // Check isAlive too because right after removeDatanode(),
         // isDatanodeDead() is still true 
-        if(shouldCountVersion(dn))
+        if (shouldCountVersion(dn)) {
-        {
+          Integer num = datanodesSoftwareVersions.get(dn.getSoftwareVersion());
-          Integer num = versionCount.get(dn.getSoftwareVersion());
           num = num == null ? 1 : num+1;
-          versionCount.put(dn.getSoftwareVersion(), num);
+          datanodesSoftwareVersions.put(dn.getSoftwareVersion(), num);
         }
       }
-      this.datanodesSoftwareVersions = versionCount;
     }
   }
 
   public HashMap<String, Integer> getDatanodesSoftwareVersions() {
-    synchronized(datanodeMap) {
+    synchronized(this) {
       return new HashMap<> (this.datanodesSoftwareVersions);
     }
   }
@@ -747,13 +736,11 @@ public class DatanodeManager {
   /**
    * Resolve network locations for specified hosts
    *
-   * @param names
    * @return Network locations if available, Else returns null
    */
   public List<String> resolveNetworkLocation(List<String> names) {
     // resolve its network location
-    List<String> rName = dnsToSwitchMapping.resolve(names);
+    return dnsToSwitchMapping.resolve(names);
-    return rName;
   }
 
   /**
@@ -807,10 +794,9 @@ public class DatanodeManager {
    * This is used to not to display a decommissioned datanode to the operators.
    * @param nodeList , array list of live or dead nodes.
    */
-  private void removeDecomNodeFromList(
+  private static void removeDecomNodeFromList(
       final List<DatanodeDescriptor> nodeList) {
-    Iterator<DatanodeDescriptor> it=null;
+    for (Iterator<DatanodeDescriptor> it = nodeList.iterator(); it.hasNext();) {
-    for (it = nodeList.iterator(); it.hasNext();) {
       DatanodeDescriptor node = it.next();
       if (node.isDecommissioned()) {
         it.remove();
@@ -968,6 +954,7 @@ public class DatanodeManager {
   
         // register new datanode
         addDatanode(nodeDescr);
+        blockManager.getBlockReportLeaseManager().register(nodeDescr);
         // also treat the registration message as a heartbeat
         // no need to update its timestamp
         // because its is done when the descriptor is created
@@ -1030,7 +1017,11 @@ public class DatanodeManager {
    * 4. Removed from exclude --> stop decommission.
    */
   private void refreshDatanodes() {
-    for(DatanodeDescriptor node : datanodeMap.values()) {
+    final Map<String, DatanodeDescriptor> copy;
+    synchronized (this) {
+      copy = new HashMap<>(datanodeMap);
+    }
+    for (DatanodeDescriptor node : copy.values()) {
       // Check if not include.
       if (!hostFileManager.isIncluded(node)) {
         node.setDisallowed(true); // case 2.
@@ -1047,7 +1038,7 @@ public class DatanodeManager {
   /** @return the number of live datanodes. */
   public int getNumLiveDataNodes() {
     int numLive = 0;
-    synchronized (datanodeMap) {
+    synchronized (this) {
       for(DatanodeDescriptor dn : datanodeMap.values()) {
         if (!isDatanodeDead(dn) ) {
           numLive++;
@@ -1252,7 +1243,7 @@ public class DatanodeManager {
     final HostFileManager.HostSet includedNodes = hostFileManager.getIncludes();
     final HostFileManager.HostSet excludedNodes = hostFileManager.getExcludes();
 
-    synchronized(datanodeMap) {
+    synchronized(this) {
       nodes = new ArrayList<>(datanodeMap.size());
       for (DatanodeDescriptor dn : datanodeMap.values()) {
         final boolean isDead = isDatanodeDead(dn);
@@ -1327,52 +1318,18 @@ public class DatanodeManager {
     node.setLastUpdateMonotonic(0);
   }
 
-  /** Handle heartbeat from datanodes. */
+  private BlockRecoveryCommand getBlockRecoveryCommand(String blockPoolId,
-  public DatanodeCommand[] handleHeartbeat(DatanodeRegistration nodeReg,
+      DatanodeDescriptor nodeinfo) {
-      StorageReport[] reports, final String blockPoolId,
-      long cacheCapacity, long cacheUsed, int xceiverCount, 
-      int maxTransfers, int failedVolumes,
-      VolumeFailureSummary volumeFailureSummary) throws IOException {
-    synchronized (heartbeatManager) {
-      synchronized (datanodeMap) {
-        DatanodeDescriptor nodeinfo;
-        try {
-          nodeinfo = getDatanode(nodeReg);
-        } catch(UnregisteredNodeException e) {
-          return new DatanodeCommand[]{RegisterCommand.REGISTER};
-        }
-        
-        // Check if this datanode should actually be shutdown instead. 
-        if (nodeinfo != null && nodeinfo.isDisallowed()) {
-          setDatanodeDead(nodeinfo);
-          throw new DisallowedDatanodeException(nodeinfo);
-        }
-
-        if (nodeinfo == null || !nodeinfo.isAlive()) {
-          return new DatanodeCommand[]{RegisterCommand.REGISTER};
-        }
-
-        heartbeatManager.updateHeartbeat(nodeinfo, reports,
-                                         cacheCapacity, cacheUsed,
-                                         xceiverCount, failedVolumes,
-                                         volumeFailureSummary);
-
-        // If we are in safemode, do not send back any recovery / replication
-        // requests. Don't even drain the existing queue of work.
-        if(namesystem.isInSafeMode()) {
-          return new DatanodeCommand[0];
-        }
-
-        //check lease recovery
     BlockInfo[] blocks = nodeinfo.getLeaseRecoveryCommand(Integer.MAX_VALUE);
-        if (blocks != null) {
+    if (blocks == null) {
-          BlockRecoveryCommand brCommand = new BlockRecoveryCommand(
+      return null;
-              blocks.length);
+    }
+    BlockRecoveryCommand brCommand = new BlockRecoveryCommand(blocks.length);
     for (BlockInfo b : blocks) {
       BlockUnderConstructionFeature uc = b.getUnderConstructionFeature();
       assert uc != null;
       final DatanodeStorageInfo[] storages = uc.getExpectedStorageLocations();
-            // Skip stale nodes during recovery - not heart beated for some time (30s by default).
+      // Skip stale nodes during recovery
       final List<DatanodeStorageInfo> recoveryLocations =
           new ArrayList<>(storages.length);
       for (DatanodeStorageInfo storage : storages) {
@@ -1388,72 +1345,50 @@ public class DatanodeManager {
       ExtendedBlock primaryBlock = (copyOnTruncateRecovery) ?
           new ExtendedBlock(blockPoolId, uc.getTruncateBlock()) :
           new ExtendedBlock(blockPoolId, b);
-            // If we only get 1 replica after eliminating stale nodes, then choose all
+      // If we only get 1 replica after eliminating stale nodes, choose all
       // replicas for recovery and let the primary data node handle failures.
       DatanodeInfo[] recoveryInfos;
       if (recoveryLocations.size() > 1) {
         if (recoveryLocations.size() != storages.length) {
-                LOG.info("Skipped stale nodes for recovery : " +
+          LOG.info("Skipped stale nodes for recovery : "
-                    (storages.length - recoveryLocations.size()));
+              + (storages.length - recoveryLocations.size()));
         }
-              recoveryInfos =
+        recoveryInfos = DatanodeStorageInfo.toDatanodeInfos(recoveryLocations);
-                  DatanodeStorageInfo.toDatanodeInfos(recoveryLocations);
       } else {
-              // If too many replicas are stale, then choose all replicas to participate
+        // If too many replicas are stale, then choose all replicas to
-              // in block recovery.
+        // participate in block recovery.
         recoveryInfos = DatanodeStorageInfo.toDatanodeInfos(storages);
       }
       RecoveringBlock rBlock;
-            if(truncateRecovery) {
+      if (truncateRecovery) {
-              Block recoveryBlock = (copyOnTruncateRecovery) ? b :
+        Block recoveryBlock = (copyOnTruncateRecovery) ? b : uc.getTruncateBlock();
-                  uc.getTruncateBlock();
+        rBlock = new RecoveringBlock(primaryBlock, recoveryInfos, recoveryBlock);
-              rBlock = new RecoveringBlock(primaryBlock, recoveryInfos,
-                  recoveryBlock);
       } else {
         rBlock = new RecoveringBlock(primaryBlock, recoveryInfos,
             uc.getBlockRecoveryId());
       }
       brCommand.add(rBlock);
     }
-          return new DatanodeCommand[] { brCommand };
+    return brCommand;
   }
 
-        final List<DatanodeCommand> cmds = new ArrayList<>();
+  private void addCacheCommands(String blockPoolId, DatanodeDescriptor nodeinfo,
-        //check pending replication
+      List<DatanodeCommand> cmds) {
-        List<BlockTargetPair> pendingList = nodeinfo.getReplicationCommand(
-              maxTransfers);
-        if (pendingList != null) {
-          cmds.add(new BlockCommand(DatanodeProtocol.DNA_TRANSFER, blockPoolId,
-              pendingList));
-        }
-        // checking pending erasure coding tasks
-        List<BlockECRecoveryInfo> pendingECList =
-            nodeinfo.getErasureCodeCommand(maxTransfers);
-        if (pendingECList != null) {
-          cmds.add(new BlockECRecoveryCommand(DatanodeProtocol.DNA_ERASURE_CODING_RECOVERY,
-              pendingECList));
-        }
-        //check block invalidation
-        Block[] blks = nodeinfo.getInvalidateBlocks(blockInvalidateLimit);
-        if (blks != null) {
-          cmds.add(new BlockCommand(DatanodeProtocol.DNA_INVALIDATE,
-              blockPoolId, blks));
-        }
     boolean sendingCachingCommands = false;
-        long nowMs = monotonicNow();
+    final long nowMs = monotonicNow();
     if (shouldSendCachingCommands &&
         ((nowMs - nodeinfo.getLastCachingDirectiveSentTimeMs()) >=
             timeBetweenResendingCachingDirectivesMs)) {
-          DatanodeCommand pendingCacheCommand =
+      DatanodeCommand pendingCacheCommand = getCacheCommand(
-              getCacheCommand(nodeinfo.getPendingCached(), nodeinfo,
+          nodeinfo.getPendingCached(), DatanodeProtocol.DNA_CACHE,
-                DatanodeProtocol.DNA_CACHE, blockPoolId);
+          blockPoolId);
       if (pendingCacheCommand != null) {
         cmds.add(pendingCacheCommand);
         sendingCachingCommands = true;
       }
-          DatanodeCommand pendingUncacheCommand =
+      DatanodeCommand pendingUncacheCommand = getCacheCommand(
-              getCacheCommand(nodeinfo.getPendingUncached(), nodeinfo,
+          nodeinfo.getPendingUncached(), DatanodeProtocol.DNA_UNCACHE,
-                DatanodeProtocol.DNA_UNCACHE, blockPoolId);
+          blockPoolId);
       if (pendingUncacheCommand != null) {
         cmds.add(pendingUncacheCommand);
         sendingCachingCommands = true;
@@ -1462,7 +1397,70 @@ public class DatanodeManager {
         nodeinfo.setLastCachingDirectiveSentTimeMs(nowMs);
       }
     }
+  }
 
+  /** Handle heartbeat from datanodes. */
+  public DatanodeCommand[] handleHeartbeat(DatanodeRegistration nodeReg,
+      StorageReport[] reports, final String blockPoolId,
+      long cacheCapacity, long cacheUsed, int xceiverCount, 
+      int maxTransfers, int failedVolumes,
+      VolumeFailureSummary volumeFailureSummary) throws IOException {
+    final DatanodeDescriptor nodeinfo;
+    try {
+      nodeinfo = getDatanode(nodeReg);
+    } catch (UnregisteredNodeException e) {
+      return new DatanodeCommand[]{RegisterCommand.REGISTER};
+    }
+
+    // Check if this datanode should actually be shutdown instead.
+    if (nodeinfo != null && nodeinfo.isDisallowed()) {
+      setDatanodeDead(nodeinfo);
+      throw new DisallowedDatanodeException(nodeinfo);
+    }
+
+    if (nodeinfo == null || !nodeinfo.isAlive()) {
+      return new DatanodeCommand[]{RegisterCommand.REGISTER};
+    }
+    heartbeatManager.updateHeartbeat(nodeinfo, reports, cacheCapacity,
+        cacheUsed, xceiverCount, failedVolumes, volumeFailureSummary);
+
+    // If we are in safemode, do not send back any recovery / replication
+    // requests. Don't even drain the existing queue of work.
+    if (namesystem.isInSafeMode()) {
+      return new DatanodeCommand[0];
+    }
+
+    // block recovery command
+    final BlockRecoveryCommand brCommand = getBlockRecoveryCommand(blockPoolId,
+        nodeinfo);
+    if (brCommand != null) {
+      return new DatanodeCommand[]{brCommand};
+    }
+
+    final List<DatanodeCommand> cmds = new ArrayList<>();
+    // check pending replication
+    List<BlockTargetPair> pendingList = nodeinfo.getReplicationCommand(
+        maxTransfers);
+    if (pendingList != null) {
+      cmds.add(new BlockCommand(DatanodeProtocol.DNA_TRANSFER, blockPoolId,
+          pendingList));
+    }
+    // check pending erasure coding tasks
+    List<BlockECRecoveryInfo> pendingECList = nodeinfo.getErasureCodeCommand(
+        maxTransfers);
+    if (pendingECList != null) {
+      cmds.add(new BlockECRecoveryCommand(DNA_ERASURE_CODING_RECOVERY,
+          pendingECList));
+    }
+    // check block invalidation
+    Block[] blks = nodeinfo.getInvalidateBlocks(blockInvalidateLimit);
+    if (blks != null) {
+      cmds.add(new BlockCommand(DatanodeProtocol.DNA_INVALIDATE, blockPoolId,
+          blks));
+    }
+    // cache commands
+    addCacheCommands(blockPoolId, nodeinfo, cmds);
+    // key update command
     blockManager.addKeyUpdateCommand(cmds, nodeinfo);
 
     // check for balancer bandwidth update
@@ -1475,8 +1473,6 @@ public class DatanodeManager {
     if (!cmds.isEmpty()) {
       return cmds.toArray(new DatanodeCommand[cmds.size()]);
     }
-      }
-    }
 
     return new DatanodeCommand[0];
   }
@@ -1486,14 +1482,13 @@ public class DatanodeManager {
    *
    * @param list       The {@link CachedBlocksList}.  This function 
    *                   clears the list.
-   * @param datanode   The datanode.
    * @param action     The action to perform in the command.
    * @param poolId     The block pool id.
    * @return           A DatanodeCommand to be sent back to the DN, or null if
    *                   there is nothing to be done.
    */
-  private DatanodeCommand getCacheCommand(CachedBlocksList list,
+  private DatanodeCommand getCacheCommand(CachedBlocksList list, int action,
-      DatanodeDescriptor datanode, int action, String poolId) {
+      String poolId) {
     int length = list.size();
     if (length == 0) {
       return null;
@@ -1501,9 +1496,7 @@ public class DatanodeManager {
     // Read the existing cache commands.
     long[] blockIds = new long[length];
     int i = 0;
-    for (Iterator<CachedBlock> iter = list.iterator();
+    for (CachedBlock cachedBlock : list) {
-            iter.hasNext(); ) {
-      CachedBlock cachedBlock = iter.next();
       blockIds[i++] = cachedBlock.getBlockId();
     }
     return new BlockIdCommand(action, poolId, blockIds);
@@ -1524,7 +1517,7 @@ public class DatanodeManager {
    * @throws IOException
    */
   public void setBalancerBandwidth(long bandwidth) throws IOException {
-    synchronized(datanodeMap) {
+    synchronized(this) {
       for (DatanodeDescriptor nodeInfo : datanodeMap.values()) {
         nodeInfo.setBalancerBandwidth(bandwidth);
       }
@@ -1533,7 +1526,7 @@ public class DatanodeManager {
   
   public void markAllDatanodesStale() {
     LOG.info("Marking all datandoes as stale");
-    synchronized (datanodeMap) {
+    synchronized (this) {
       for (DatanodeDescriptor dn : datanodeMap.values()) {
         for(DatanodeStorageInfo storage : dn.getStorageInfos()) {
           storage.markStaleAfterFailover();
@@ -1548,7 +1541,7 @@ public class DatanodeManager {
    * recoveries, and replication requests.
    */
   public void clearPendingQueues() {
-    synchronized (datanodeMap) {
+    synchronized (this) {
       for (DatanodeDescriptor dn : datanodeMap.values()) {
         dn.clearBlockQueues();
       }
@@ -1560,7 +1553,7 @@ public class DatanodeManager {
    * know about.
    */
   public void resetLastCachingDirectiveSentTime() {
-    synchronized (datanodeMap) {
+    synchronized (this) {
       for (DatanodeDescriptor dn : datanodeMap.values()) {
         dn.setLastCachingDirectiveSentTimeMs(0L);
       }
@@ -1573,11 +1566,13 @@ public class DatanodeManager {
   }
 
   public void clearPendingCachingCommands() {
+    synchronized (this) {
       for (DatanodeDescriptor dn : datanodeMap.values()) {
         dn.getPendingCached().clear();
         dn.getPendingUncached().clear();
       }
     }
+  }
 
   public void setShouldSendCachingCommands(boolean shouldSendCachingCommands) {
     this.shouldSendCachingCommands = shouldSendCachingCommands;

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

@@ -27,6 +27,8 @@ import org.apache.hadoop.fs.StorageType;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.protocol.DatanodeID;
 import org.apache.hadoop.hdfs.server.namenode.Namesystem;
+import org.apache.hadoop.hdfs.server.protocol.DatanodeCommand;
+import org.apache.hadoop.hdfs.server.protocol.RegisterCommand;
 import org.apache.hadoop.hdfs.server.protocol.StorageReport;
 import org.apache.hadoop.hdfs.server.protocol.VolumeFailureSummary;
 import org.apache.hadoop.util.Daemon;

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

@@ -418,9 +418,6 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
    */
   private volatile boolean needRollbackFsImage;
 
-  // Block pool ID used by this namenode
-  private String blockPoolId;
-
   final LeaseManager leaseManager = new LeaseManager(this); 
 
   Daemon nnrmthread = null; // NamenodeResourceMonitor thread
@@ -2348,12 +2345,11 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
   }
 
   ExtendedBlock getExtendedBlock(Block blk) {
-    return new ExtendedBlock(blockPoolId, blk);
+    return new ExtendedBlock(getBlockPoolId(), blk);
   }
   
   void setBlockPoolId(String bpid) {
-    blockPoolId = bpid;
+    blockManager.setBlockPoolId(bpid);
-    blockManager.setBlockPoolId(blockPoolId);
   }
 
   /**
@@ -3507,7 +3503,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
       final int maxTransfer = blockManager.getMaxReplicationStreams()
           - xmitsInProgress;
       DatanodeCommand[] cmds = blockManager.getDatanodeManager().handleHeartbeat(
-          nodeReg, reports, blockPoolId, cacheCapacity, cacheUsed,
+          nodeReg, reports, getBlockPoolId(), cacheCapacity, cacheUsed,
           xceiverCount, maxTransfer, failedVolumes, volumeFailureSummary);
       long blockReportLeaseId = 0;
       if (requestFullBlockReportLease) {
@@ -5371,7 +5367,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
   
   @Override  // NameNodeMXBean
   public String getBlockPoolId() {
-    return blockPoolId;
+    return getBlockManager().getBlockPoolId();
   }
   
   @Override  // NameNodeMXBean
@@ -5960,7 +5956,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
   }
 
   void setRollingUpgradeInfo(boolean createdRollbackImages, long startTime) {
-    rollingUpgradeInfo = new RollingUpgradeInfo(blockPoolId,
+    rollingUpgradeInfo = new RollingUpgradeInfo(getBlockPoolId(),
         createdRollbackImages, startTime, 0L);
   }