(recommit) HDFS-3089. Move FSDatasetInterface and the related classes to a package.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1305603 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -263,6 +263,9 @@ Release 0.23.3 - UNRELEASED
     HDFS-3071. haadmin failover command does not provide enough detail when
     target NN is not ready to be active. (todd)
 
+    HDFS-3089. Move FSDatasetInterface and the related classes to a package.
+    (szetszwo)
+
   OPTIMIZATIONS
 
     HDFS-3024. Improve performance of stringification in addStoredBlock (todd)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -237,9 +237,6 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final int     DFS_DATANODE_SCAN_PERIOD_HOURS_DEFAULT = 0;
   public static final String  DFS_DATANODE_TRANSFERTO_ALLOWED_KEY = "dfs.datanode.transferTo.allowed";
   public static final boolean DFS_DATANODE_TRANSFERTO_ALLOWED_DEFAULT = true;
-  public static final String  DFS_DATANODE_BLOCKVOLUMECHOICEPOLICY = "dfs.datanode.block.volume.choice.policy";
-  public static final String  DFS_DATANODE_BLOCKVOLUMECHOICEPOLICY_DEFAULT =
-    "org.apache.hadoop.hdfs.server.datanode.RoundRobinVolumesPolicy";
   public static final String  DFS_HEARTBEAT_INTERVAL_KEY = "dfs.heartbeat.interval";
   public static final long    DFS_HEARTBEAT_INTERVAL_DEFAULT = 3;
   public static final String  DFS_NAMENODE_DECOMMISSION_INTERVAL_KEY = "dfs.namenode.decommission.interval";
@@ -305,6 +302,7 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   //Keys with no defaults
   public static final String  DFS_DATANODE_PLUGINS_KEY = "dfs.datanode.plugins";
   public static final String  DFS_DATANODE_FSDATASET_FACTORY_KEY = "dfs.datanode.fsdataset.factory";
+  public static final String  DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY = "dfs.datanode.fsdataset.volume.choosing.policy";
   public static final String  DFS_DATANODE_SOCKET_WRITE_TIMEOUT_KEY = "dfs.datanode.socket.write.timeout";
   public static final String  DFS_DATANODE_STARTUP_KEY = "dfs.datanode.startup";
   public static final String  DFS_NAMENODE_PLUGINS_KEY = "dfs.namenode.plugins";

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

@@ -44,7 +44,9 @@ import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.server.common.GenerationStamp;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.RollingLogs;
 import org.apache.hadoop.hdfs.util.DataTransferThrottler;
 import org.apache.hadoop.io.IOUtils;
 
@@ -72,7 +74,7 @@ class BlockPoolSliceScanner {
   private final AtomicLong lastScanTime = new AtomicLong();
 
   private final DataNode datanode;
-  private final FSDatasetInterface<? extends FsVolumeSpi> dataset;
+  private final FsDatasetSpi<? extends FsVolumeSpi> dataset;
   
   private final SortedSet<BlockScanInfo> blockInfoSet
       = new TreeSet<BlockScanInfo>();
@@ -134,8 +136,7 @@ class BlockPoolSliceScanner {
   }
   
   BlockPoolSliceScanner(String bpid, DataNode datanode,
-      FSDatasetInterface<? extends FsVolumeSpi> dataset,
+      FsDatasetSpi<? extends FsVolumeSpi> dataset, Configuration conf) {
-      Configuration conf) {
     this.datanode = datanode;
     this.dataset = dataset;
     this.blockPoolId  = bpid;

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

@@ -31,6 +31,7 @@ import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 
 /**
@@ -43,7 +44,7 @@ import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 public class DataBlockScanner implements Runnable {
   public static final Log LOG = LogFactory.getLog(DataBlockScanner.class);
   private final DataNode datanode;
-  private final FSDatasetInterface<? extends FsVolumeSpi> dataset;
+  private final FsDatasetSpi<? extends FsVolumeSpi> dataset;
   private final Configuration conf;
   
   /**
@@ -55,7 +56,7 @@ public class DataBlockScanner implements Runnable {
   Thread blockScannerThread = null;
   
   DataBlockScanner(DataNode datanode,
-      FSDatasetInterface<? extends FsVolumeSpi> dataset,
+      FsDatasetSpi<? extends FsVolumeSpi> dataset,
       Configuration conf) {
     this.datanode = datanode;
     this.dataset = dataset;

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

@@ -122,6 +122,7 @@ import org.apache.hadoop.hdfs.server.common.JspHelper;
 import org.apache.hadoop.hdfs.server.common.StorageInfo;
 import org.apache.hadoop.hdfs.server.common.Util;
 import org.apache.hadoop.hdfs.server.datanode.SecureDataNodeStarter.SecureResources;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 import org.apache.hadoop.hdfs.server.datanode.metrics.DataNodeMetrics;
 import org.apache.hadoop.hdfs.server.datanode.web.resources.DatanodeWebHdfsMethods;
@@ -231,7 +232,7 @@ public class DataNode extends Configured
   
   volatile boolean shouldRun = true;
   private BlockPoolManager blockPoolManager;
-  volatile FSDatasetInterface<? extends FsVolumeSpi> data = null;
+  volatile FsDatasetSpi<? extends FsVolumeSpi> data = null;
   private String clusterId = null;
 
   public final static String EMPTY_DEL_HINT = "";
@@ -809,8 +810,8 @@ public class DataNode extends Configured
    * handshake with the the first namenode is completed.
    */
   private void initStorage(final NamespaceInfo nsInfo) throws IOException {
-    final FSDatasetInterface.Factory<? extends FSDatasetInterface<?>> factory
+    final FsDatasetSpi.Factory<? extends FsDatasetSpi<?>> factory
-        = FSDatasetInterface.Factory.getFactory(conf);
+        = FsDatasetSpi.Factory.getFactory(conf);
     
     if (!factory.isSimulated()) {
       final StartupOption startOpt = getStartupOption(conf);
@@ -828,7 +829,7 @@ public class DataNode extends Configured
 
     synchronized(this)  {
       if (data == null) {
-        data = factory.createFSDatasetInterface(this, storage, conf);
+        data = factory.newInstance(this, storage, conf);
       }
     }
   }
@@ -1695,7 +1696,7 @@ public class DataNode extends Configured
    * 
    * @return the fsdataset that stores the blocks
    */
-  FSDatasetInterface<?> getFSDataset() {
+  FsDatasetSpi<?> getFSDataset() {
     return data;
   }
 

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

@@ -43,6 +43,7 @@ import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.server.common.GenerationStamp;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 import org.apache.hadoop.util.Daemon;
 
@@ -55,7 +56,7 @@ public class DirectoryScanner implements Runnable {
   private static final Log LOG = LogFactory.getLog(DirectoryScanner.class);
 
   private final DataNode datanode;
-  private final FSDatasetInterface<?> dataset;
+  private final FsDatasetSpi<?> dataset;
   private final ExecutorService reportCompileThreadPool;
   private final ScheduledExecutorService masterThread;
   private final long scanPeriodMsecs;
@@ -219,7 +220,7 @@ public class DirectoryScanner implements Runnable {
     }
   }
 
-  DirectoryScanner(DataNode dn, FSDatasetInterface<?> dataset, Configuration conf) {
+  DirectoryScanner(DataNode dn, FsDatasetSpi<?> dataset, Configuration conf) {
     this.datanode = dn;
     this.dataset = dataset;
     int interval = conf.getInt(DFSConfigKeys.DFS_DATANODE_DIRECTORYSCAN_INTERVAL_KEY,
@@ -411,7 +412,7 @@ public class DirectoryScanner implements Runnable {
   }
 
   /** Is the given volume still valid in the dataset? */
-  private static boolean isValid(final FSDatasetInterface<?> dataset,
+  private static boolean isValid(final FsDatasetSpi<?> dataset,
       final FsVolumeSpi volume) {
     for (FsVolumeSpi vol : dataset.getVolumes()) {
       if (vol == volume) {

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

@@ -61,10 +61,14 @@ import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.RecoveryInProgressException;
 import org.apache.hadoop.hdfs.server.common.GenerationStamp;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.ReplicaState;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.LengthInputStream;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.ReplicaInputStreams;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.ReplicaOutputStreams;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.RollingLogs;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.RoundRobinVolumeChoosingPolicy;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.VolumeChoosingPolicy;
 import org.apache.hadoop.hdfs.server.datanode.metrics.FSDatasetMBean;
 import org.apache.hadoop.hdfs.server.protocol.BlockRecoveryCommand.RecoveringBlock;
 import org.apache.hadoop.hdfs.server.protocol.ReplicaRecoveryInfo;
@@ -82,13 +86,13 @@ import org.apache.hadoop.util.ReflectionUtils;
  *
  ***************************************************/
 @InterfaceAudience.Private
-class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
+public class FSDataset implements FsDatasetSpi<FSDataset.FSVolume> {
   /**
    * A factory for creating FSDataset objects.
    */
-  static class Factory extends FSDatasetInterface.Factory<FSDataset> {
+  public static class Factory extends FsDatasetSpi.Factory<FSDataset> {
     @Override
-    public FSDataset createFSDatasetInterface(DataNode datanode,
+    public FSDataset newInstance(DataNode datanode,
         DataStorage storage, Configuration conf) throws IOException {
       return new FSDataset(datanode, storage, conf);
     }
@@ -823,11 +827,11 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
      */
     private volatile List<FSVolume> volumes = null;
 
-    BlockVolumeChoosingPolicy<FSVolume> blockChooser;
+    final VolumeChoosingPolicy<FSVolume> blockChooser;
     int numFailedVolumes;
 
     FSVolumeSet(List<FSVolume> volumes, int failedVols,
-        BlockVolumeChoosingPolicy<FSVolume> blockChooser) {
+        VolumeChoosingPolicy<FSVolume> blockChooser) {
       this.volumes = Collections.unmodifiableList(volumes);
       this.blockChooser = blockChooser;
       this.numFailedVolumes = failedVols;
@@ -1018,7 +1022,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     }
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public List<FSVolume> getVolumes() {
     return volumes.volumes;
   }
@@ -1029,7 +1033,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return r != null? (FSVolume)r.getVolume(): null;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized Block getStoredBlock(String bpid, long blkid)
       throws IOException {
     File blockfile = getFile(bpid, blkid);
@@ -1066,7 +1070,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return null;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public LengthInputStream getMetaDataInputStream(ExtendedBlock b)
       throws IOException {
     final File meta = getMetaFile(b);
@@ -1125,11 +1129,11 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     volumeMap = new ReplicasMap(this);
 
     @SuppressWarnings("unchecked")
-    final BlockVolumeChoosingPolicy<FSVolume> blockChooserImpl =
+    final VolumeChoosingPolicy<FSVolume> blockChooserImpl =
         ReflectionUtils.newInstance(conf.getClass(
-            DFSConfigKeys.DFS_DATANODE_BLOCKVOLUMECHOICEPOLICY,
+            DFSConfigKeys.DFS_DATANODE_FSDATASET_VOLUME_CHOOSING_POLICY_KEY,
-            RoundRobinVolumesPolicy.class,
+            RoundRobinVolumeChoosingPolicy.class,
-            BlockVolumeChoosingPolicy.class), conf);
+            VolumeChoosingPolicy.class), conf);
     volumes = new FSVolumeSet(volArray, volsFailed, blockChooserImpl);
     volumes.getVolumeMap(volumeMap);
 
@@ -1164,7 +1168,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   /**
    * Return true - if there are still valid volumes on the DataNode. 
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public boolean hasEnoughResource() {
     return getVolumes().size() >= validVolsRequired; 
   }
@@ -1199,7 +1203,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   /**
    * Find the block's on-disk length
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public long getLength(ExtendedBlock b) throws IOException {
     return getBlockFile(b).length();
   }
@@ -1243,7 +1247,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return f;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public InputStream getBlockInputStream(ExtendedBlock b,
       long seekOffset) throws IOException {
     File blockFile = getBlockFileNoExistsCheck(b);
@@ -1301,7 +1305,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   /**
    * Returns handles to the block file and its metadata file
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInputStreams getTmpInputStreams(ExtendedBlock b, 
                           long blkOffset, long ckoff) throws IOException {
     ReplicaInfo info = getReplicaInfo(b);
@@ -1406,7 +1410,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   }
 
 
-  @Override  // FSDatasetInterface
+  @Override  // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface append(ExtendedBlock b,
       long newGS, long expectedBlockLen) throws IOException {
     // If the block was successfully finalized because all packets
@@ -1547,7 +1551,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return replicaInfo;
   }
   
-  @Override  // FSDatasetInterface
+  @Override  // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface recoverAppend(ExtendedBlock b,
       long newGS, long expectedBlockLen) throws IOException {
     DataNode.LOG.info("Recover failed append to " + b);
@@ -1564,7 +1568,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     }
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void recoverClose(ExtendedBlock b, long newGS,
       long expectedBlockLen) throws IOException {
     DataNode.LOG.info("Recover failed close " + b);
@@ -1606,7 +1610,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     }
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface createRbw(ExtendedBlock b)
       throws IOException {
     ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), 
@@ -1626,7 +1630,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return newReplicaInfo;
   }
   
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface recoverRbw(ExtendedBlock b,
       long newGS, long minBytesRcvd, long maxBytesRcvd)
       throws IOException {
@@ -1671,7 +1675,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return rbw;
   }
   
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface convertTemporaryToRbw(
       final ExtendedBlock b) throws IOException {
     final long blockId = b.getBlockId();
@@ -1732,7 +1736,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return rbw;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface createTemporary(ExtendedBlock b)
       throws IOException {
     ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), b.getBlockId());
@@ -1756,7 +1760,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
    * Sets the offset in the meta file so that the
    * last checksum will be overwritten.
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void adjustCrcChannelPosition(ExtendedBlock b, ReplicaOutputStreams streams, 
       int checksumSize) throws IOException {
     FileOutputStream file = (FileOutputStream) streams.getChecksumOut();
@@ -1781,7 +1785,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   /**
    * Complete the block write!
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized void finalizeBlock(ExtendedBlock b) throws IOException {
     ReplicaInfo replicaInfo = getReplicaInfo(b);
     if (replicaInfo.getState() == ReplicaState.FINALIZED) {
@@ -1818,7 +1822,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   /**
    * Remove the temporary block file (if any)
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized void unfinalizeBlock(ExtendedBlock b) throws IOException {
     ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), 
         b.getLocalBlock());
@@ -1863,7 +1867,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   /**
    * Generates a block report from the in-memory block map.
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public BlockListAsLongs getBlockReport(String bpid) {
     int size =  volumeMap.size(bpid);
     ArrayList<ReplicaInfo> finalized = new ArrayList<ReplicaInfo>(size);
@@ -1914,7 +1918,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
    * Check whether the given block is a valid one.
    * valid means finalized
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public boolean isValidBlock(ExtendedBlock b) {
     return isValid(b, ReplicaState.FINALIZED);
   }
@@ -1922,7 +1926,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   /**
    * Check whether the given block is a valid RBW.
    */
-  @Override // {@link FSDatasetInterface}
+  @Override // {@link FsDatasetSpi}
   public boolean isValidRbw(final ExtendedBlock b) {
     return isValid(b, ReplicaState.RBW);
   }
@@ -1987,7 +1991,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
    * could lazily garbage-collect the block, but why bother?
    * just get rid of it.
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void invalidate(String bpid, Block invalidBlks[]) throws IOException {
     boolean error = false;
     for (int i = 0; i < invalidBlks.length; i++) {
@@ -2053,7 +2057,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     datanode.notifyNamenodeDeletedBlock(block);
   }
 
-  @Override // {@link FSDatasetInterface}
+  @Override // {@link FsDatasetSpi}
   public synchronized boolean contains(final ExtendedBlock block) {
     final long blockId = block.getLocalBlock().getBlockId();
     return getFile(block.getBlockPoolId(), blockId) != null;
@@ -2078,7 +2082,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
    * to these volumes
    * @throws DiskErrorException
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void checkDataDir() throws DiskErrorException {
     long totalBlocks=0, removedBlocks=0;
     List<FSVolume> failedVols =  volumes.checkDirs();
@@ -2122,7 +2126,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   }
     
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public String toString() {
     return "FSDataset{dirpath='"+volumes+"'}";
   }
@@ -2153,7 +2157,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     DataNode.LOG.info("Registered FSDatasetState MBean");
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void shutdown() {
     if (mbeanName != null)
       MBeans.unregister(mbeanName);
@@ -2334,7 +2338,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
   /**
    * @deprecated use {@link #fetchReplicaInfo(String, long)} instead.
    */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   @Deprecated
   public ReplicaInfo getReplica(String bpid, long blockId) {
     return volumeMap.get(bpid, blockId);
@@ -2346,7 +2350,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return r == null? "null": r.toString();
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaRecoveryInfo initReplicaRecovery(
       RecoveringBlock rBlock) throws IOException {
     return initReplicaRecovery(rBlock.getBlock().getBlockPoolId(),
@@ -2419,7 +2423,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return rur.createInfo();
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized String updateReplicaUnderRecovery(
                                     final ExtendedBlock oldBlock,
                                     final long recoveryId,
@@ -2501,7 +2505,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return finalizeReplica(bpid, rur);
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized long getReplicaVisibleLength(final ExtendedBlock block)
   throws IOException {
     final Replica replica = getReplicaInfo(block.getBlockPoolId(), 
@@ -2584,7 +2588,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     return info;
   }
 
-  @Override //FSDatasetInterface
+  @Override //FsDatasetSpi
   public synchronized void deleteBlockPool(String bpid, boolean force)
       throws IOException {
     if (!force) {
@@ -2602,7 +2606,7 @@ class FSDataset implements FSDatasetInterface<FSDataset.FSVolume> {
     }
   }
   
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public BlockLocalPathInfo getBlockLocalPathInfo(ExtendedBlock block)
       throws IOException {
     File datafile = getBlockFile(block);

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

@@ -25,7 +25,7 @@ import org.apache.hadoop.util.DataChecksum;
 /** 
  * This defines the interface of a replica in Pipeline that's being written to
  */
-interface ReplicaInPipelineInterface extends Replica {
+public interface ReplicaInPipelineInterface extends Replica {
   /**
    * Set the number of bytes received
    * @param bytesReceived number of bytes received

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

@@ -15,7 +15,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.hadoop.hdfs.server.datanode;
+package org.apache.hadoop.hdfs.server.datanode.fsdataset;
 
 
 import java.io.File;
@@ -31,10 +31,11 @@ import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.BlockListAsLongs;
 import org.apache.hadoop.hdfs.protocol.BlockLocalPathInfo;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
+import org.apache.hadoop.hdfs.server.datanode.DataNode;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.LengthInputStream;
+import org.apache.hadoop.hdfs.server.datanode.DataStorage;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.ReplicaInputStreams;
+import org.apache.hadoop.hdfs.server.datanode.FSDataset;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.ReplicaOutputStreams;
+import org.apache.hadoop.hdfs.server.datanode.Replica;
+import org.apache.hadoop.hdfs.server.datanode.ReplicaInPipelineInterface;
 import org.apache.hadoop.hdfs.server.datanode.metrics.FSDatasetMBean;
 import org.apache.hadoop.hdfs.server.protocol.BlockRecoveryCommand.RecoveringBlock;
 import org.apache.hadoop.hdfs.server.protocol.ReplicaRecoveryInfo;
@@ -42,19 +43,16 @@ import org.apache.hadoop.util.DiskChecker.DiskErrorException;
 import org.apache.hadoop.util.ReflectionUtils;
 
 /**
- * This is an interface for the underlying storage that stores blocks for
+ * This is a service provider interface for the underlying storage that
- * a data node. 
+ * stores replicas for a data node.
- * Examples are the FSDataset (which stores blocks on dirs)  and 
+ * The default implementation stores replicas on local drives. 
- * SimulatedFSDataset (which simulates data).
- *
  */
 @InterfaceAudience.Private
-public interface FSDatasetInterface<V extends FsVolumeSpi>
+public interface FsDatasetSpi<V extends FsVolumeSpi> extends FSDatasetMBean {
-    extends FSDatasetMBean {
   /**
-   * A factory for creating FSDatasetInterface objects.
+   * A factory for creating {@link FsDatasetSpi} objects.
    */
-  public abstract class Factory<D extends FSDatasetInterface<?>> {
+  public static abstract class Factory<D extends FsDatasetSpi<?>> {
     /** @return the configured factory. */
     public static Factory<?> getFactory(Configuration conf) {
       @SuppressWarnings("rawtypes")
@@ -65,10 +63,9 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
       return ReflectionUtils.newInstance(clazz, conf);
     }
 
-    /** Create a FSDatasetInterface object. */
+    /** Create a new object. */
-    public abstract D createFSDatasetInterface(
+    public abstract D newInstance(DataNode datanode, DataStorage storage,
-        DataNode datanode, DataStorage storage, Configuration conf
+        Configuration conf) throws IOException;
-        ) throws IOException;
 
     /** Does the factory create simulated objects? */
     public boolean isSimulated() {
@@ -82,7 +79,8 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
    * @param prefix the prefix of the log names.
    * @return rolling logs
    */
-  public RollingLogs createRollingLogs(String bpid, String prefix) throws IOException;
+  public RollingLogs createRollingLogs(String bpid, String prefix
+      ) throws IOException;
 
   /** @return a list of volumes. */
   public List<V> getVolumes();
@@ -167,15 +165,15 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
   public ReplicaInputStreams getTmpInputStreams(ExtendedBlock b, long blkoff,
       long ckoff) throws IOException;
 
-     /**
+  /**
    * Creates a temporary replica and returns the meta information of the replica
    * 
    * @param b block
    * @return the meta info of the replica which is being written to
    * @throws IOException if an error occurs
    */
-  public ReplicaInPipelineInterface createTemporary(ExtendedBlock b)
+  public ReplicaInPipelineInterface createTemporary(ExtendedBlock b
-  throws IOException;
+      ) throws IOException;
 
   /**
    * Creates a RBW replica and returns the meta info of the replica
@@ -184,7 +182,8 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
    * @return the meta info of the replica which is being written to
    * @throws IOException if an error occurs
    */
-  public ReplicaInPipelineInterface createRbw(ExtendedBlock b) throws IOException;
+  public ReplicaInPipelineInterface createRbw(ExtendedBlock b
+      ) throws IOException;
 
   /**
    * Recovers a RBW replica and returns the meta info of the replica
@@ -197,8 +196,7 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
    * @throws IOException if an error occurs
    */
   public ReplicaInPipelineInterface recoverRbw(ExtendedBlock b, 
-      long newGS, long minBytesRcvd, long maxBytesRcvd)
+      long newGS, long minBytesRcvd, long maxBytesRcvd) throws IOException;
-  throws IOException;
 
   /**
    * Covert a temporary replica to a RBW.
@@ -217,8 +215,8 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
    * @return the meata info of the replica which is being written to
    * @throws IOException
    */
-  public ReplicaInPipelineInterface append(ExtendedBlock b, 
+  public ReplicaInPipelineInterface append(ExtendedBlock b, long newGS,
-      long newGS, long expectedBlockLen) throws IOException;
+      long expectedBlockLen) throws IOException;
 
   /**
    * Recover a failed append to a finalized replica
@@ -230,8 +228,8 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
    * @return the meta info of the replica which is being written to
    * @throws IOException
    */
-  public ReplicaInPipelineInterface recoverAppend(ExtendedBlock b,
+  public ReplicaInPipelineInterface recoverAppend(ExtendedBlock b, long newGS,
-      long newGS, long expectedBlockLen) throws IOException;
+      long expectedBlockLen) throws IOException;
   
   /**
    * Recover a failed pipeline close
@@ -242,8 +240,8 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
    * @param expectedBlockLen the number of bytes the replica is expected to have
    * @throws IOException
    */
-  public void recoverClose(ExtendedBlock b,
+  public void recoverClose(ExtendedBlock b, long newGS, long expectedBlockLen
-      long newGS, long expectedBlockLen) throws IOException;
+      ) throws IOException;
   
   /**
    * Finalizes the block previously opened for writing using writeToBlock.
@@ -300,7 +298,7 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
      * @throws DiskErrorException
      */
   public void checkDataDir() throws DiskErrorException;
-      
+
   /**
    * Shutdown the FSDataset
    */
@@ -310,12 +308,12 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
    * Sets the file pointer of the checksum stream so that the last checksum
    * will be overwritten
    * @param b block
-   * @param stream The stream for the data file and checksum file
+   * @param outs The streams for the data file and checksum file
    * @param checksumSize number of bytes each checksum has
    * @throws IOException
    */
-  public void adjustCrcChannelPosition(ExtendedBlock b, ReplicaOutputStreams stream, 
+  public void adjustCrcChannelPosition(ExtendedBlock b,
-      int checksumSize) throws IOException;
+      ReplicaOutputStreams outs, int checksumSize) throws IOException;
 
   /**
    * Checks how many valid storage volumes there are in the DataNode.
@@ -334,8 +332,8 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
    * @return actual state of the replica on this data-node or 
    * null if data-node does not have the replica.
    */
-  public ReplicaRecoveryInfo initReplicaRecovery(RecoveringBlock rBlock)
+  public ReplicaRecoveryInfo initReplicaRecovery(RecoveringBlock rBlock
-      throws IOException;
+      ) throws IOException;
 
   /**
    * Update replica's generation stamp and length and finalize it.
@@ -372,6 +370,7 @@ public interface FSDatasetInterface<V extends FsVolumeSpi>
   
   /**
    * Get {@link BlockLocalPathInfo} for the given block.
-   **/
+   */
-  public BlockLocalPathInfo getBlockLocalPathInfo(ExtendedBlock b) throws IOException;
+  public BlockLocalPathInfo getBlockLocalPathInfo(ExtendedBlock b
+      ) throws IOException;
 }

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

@@ -15,16 +15,15 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.hadoop.hdfs.server.datanode;
+package org.apache.hadoop.hdfs.server.datanode.fsdataset;
 
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.Iterator;
 
 /**
- * Rolling logs consist of a current log and a previous log.
+ * Rolling logs consist of a current log and a set of previous logs.
- * When the roll operation is invoked, current is rolled to previous
+ *
- * and previous is deleted.
  * The implementation should support a single appender and multiple readers.
  */
 public interface RollingLogs {
@@ -57,7 +56,7 @@ public interface RollingLogs {
   public Appender appender();
 
   /**
-   * Roll current to previous and delete the previous.
+   * Roll current to previous.
    *
    * @return true if the rolling succeeded.
    *   When it returns false, it is not equivalent to an error. 

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

@@ -15,16 +15,18 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.hadoop.hdfs.server.datanode;
+package org.apache.hadoop.hdfs.server.datanode.fsdataset;
 
 import java.io.IOException;
 import java.util.List;
 
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 import org.apache.hadoop.util.DiskChecker.DiskOutOfSpaceException;
 
-public class RoundRobinVolumesPolicy<V extends FsVolumeSpi>
+/**
-    implements BlockVolumeChoosingPolicy<V> {
+ * Choose volumes in round-robin order.
+ */
+public class RoundRobinVolumeChoosingPolicy<V extends FsVolumeSpi>
+    implements VolumeChoosingPolicy<V> {
 
   private int curVolume = 0;
 
@@ -55,13 +57,10 @@ public class RoundRobinVolumesPolicy<V extends FsVolumeSpi>
       }
       
       if (curVolume == startVolume) {
-        throw new DiskOutOfSpaceException(
+        throw new DiskOutOfSpaceException("Out of space: "
-            "Insufficient space for an additional block. Volume with the most available space has "
+            + "The volume with the most available space (=" + maxAvailable
-                + maxAvailable
+            + " B) is less than the block size (=" + blockSize + " B).");
-                + " bytes free, configured block size is "
-                + blockSize);
       }
     }
   }
-
 }

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

@@ -15,37 +15,29 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.hadoop.hdfs.server.datanode;
+package org.apache.hadoop.hdfs.server.datanode.fsdataset;
 
 import java.io.IOException;
 import java.util.List;
 
 import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 
-/**************************************************
+/**
- * BlockVolumeChoosingPolicy allows a DataNode to
+ * This interface specifies the policy for choosing volumes to store replicas.
- * specify what policy is to be used while choosing
+ */
- * a volume for a block request.
- *
- * Note: This is an evolving i/f and is only for
- * advanced use.
- *
- ***************************************************/
 @InterfaceAudience.Private
-public interface BlockVolumeChoosingPolicy<V extends FsVolumeSpi> {
+public interface VolumeChoosingPolicy<V extends FsVolumeSpi> {
 
   /**
-   * Returns a specific FSVolume after applying a suitable choice algorithm
+   * Choose a volume to place a replica,
-   * to place a given block, given a list of FSVolumes and the block
+   * given a list of volumes and the replica size sought for storage.
-   * size sought for storage.
    * 
-   * (Policies that maintain state must be thread-safe.)
+   * The implementations of this interface must be thread-safe.
    * 
-   * @param volumes - the array of FSVolumes that are available.
+   * @param volumes - a list of available volumes.
-   * @param blockSize - the size of the block for which a volume is sought.
+   * @param replicaSize - the size of the replica for which a volume is sought.
-   * @return the chosen volume to store the block.
+   * @return the chosen volume.
    * @throws IOException when disks are unavailable or are full.
    */
-  public V chooseVolume(List<V> volumes, long blockSize) throws IOException;
+  public V chooseVolume(List<V> volumes, long replicaSize) throws IOException;
-}
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -428,15 +428,6 @@
   </description>
 </property>
 
-<property>
-  <name>dfs.datanode.block.volume.choice.policy</name>
-  <value>org.apache.hadoop.hdfs.server.datanode.RoundRobinVolumesPolicy</value>
-  <description>The policy class to use to determine into which of the
-  datanode's available volumes a block must be written to. Default is a simple
-  round-robin policy that chooses volumes in a cyclic order.
-  </description>
-</property>
-
 <property>
   <name>dfs.heartbeat.interval</name>
   <value>3</value>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DataNodeCluster.java

@@ -25,8 +25,8 @@ import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.StartupOption;
-import org.apache.hadoop.hdfs.server.datanode.FSDatasetInterface;
 import org.apache.hadoop.hdfs.server.datanode.SimulatedFSDataset;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.namenode.CreateEditsLog;
 import org.apache.hadoop.net.DNS;
 
@@ -125,7 +125,7 @@ public class DataNodeCluster {
       } else if (args[i].equals("-simulated")) {
         SimulatedFSDataset.setFactory(conf);
       } else if (args[i].equals("-inject")) {
-        if (!FSDatasetInterface.Factory.getFactory(conf).isSimulated()) {
+        if (!FsDatasetSpi.Factory.getFactory(conf).isSimulated()) {
           System.out.print("-inject is valid only for simulated");
           printUsageExit(); 
         }
@@ -157,8 +157,7 @@ public class DataNodeCluster {
       System.out.println("No name node address and port in config");
       System.exit(-1);
     }
-    boolean simulated = 
+    boolean simulated = FsDatasetSpi.Factory.getFactory(conf).isSimulated();
-        FSDatasetInterface.Factory.getFactory(conf).isSimulated();
     System.out.println("Starting " + numDataNodes + 
           (simulated ? " Simulated " : " ") +
           " Data Nodes that will connect to Name Node at " + nameNodeAdr);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSCluster.java

@@ -17,6 +17,29 @@
  */
 package org.apache.hadoop.hdfs;
 
+import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DEFAULT_NAME_KEY;
+import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.NET_TOPOLOGY_NODE_SWITCH_MAPPING_IMPL_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INITIAL_DELAY_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_ADDRESS_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_HOST_NAME_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_HTTP_ADDRESS_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_IPC_ADDRESS_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_FEDERATION_NAMESERVICES;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_FEDERATION_NAMESERVICE_ID;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_HA_LOGROLL_PERIOD_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_HA_NAMENODES_KEY_PREFIX;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_HA_NAMENODE_ID_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_HA_STANDBY_CHECKPOINTS_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_HOSTS;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_CHECKPOINT_DIR_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_DECOMMISSION_INTERVAL_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_HTTP_ADDRESS_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_NAME_DIR_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_RPC_ADDRESS_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SAFEMODE_EXTENSION_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SHARED_EDITS_DIR_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_REPLICATION_KEY;
 import static org.apache.hadoop.hdfs.server.common.Util.fileAsURI;
 
 import java.io.File;
@@ -43,9 +66,6 @@ import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.FileUtil;
 import org.apache.hadoop.fs.Path;
-
-import static org.apache.hadoop.hdfs.DFSConfigKeys.*;
-
 import org.apache.hadoop.ha.HAServiceProtocol;
 import org.apache.hadoop.ha.HAServiceProtocolHelper;
 import org.apache.hadoop.ha.ServiceFailedException;
@@ -57,21 +77,20 @@ import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
-import org.apache.hadoop.hdfs.server.common.Storage;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.StartupOption;
+import org.apache.hadoop.hdfs.server.common.Storage;
 import org.apache.hadoop.hdfs.server.datanode.DataNode;
 import org.apache.hadoop.hdfs.server.datanode.DataNodeAdapter;
 import org.apache.hadoop.hdfs.server.datanode.DataNodeTestUtils;
 import org.apache.hadoop.hdfs.server.datanode.DataStorage;
-import org.apache.hadoop.hdfs.server.datanode.FSDatasetInterface;
 import org.apache.hadoop.hdfs.server.datanode.SimulatedFSDataset;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeRegistration;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
 import org.apache.hadoop.hdfs.tools.DFSAdmin;
-import org.apache.hadoop.ipc.RPC;
 import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
 import org.apache.hadoop.net.DNSToSwitchMapping;
 import org.apache.hadoop.net.NetUtils;
@@ -1802,7 +1821,7 @@ public class MiniDFSCluster {
       throw new IndexOutOfBoundsException();
     }
     final DataNode dn = dataNodes.get(dataNodeIndex).datanode;
-    final FSDatasetInterface<?> dataSet = DataNodeTestUtils.getFSDataset(dn);
+    final FsDatasetSpi<?> dataSet = DataNodeTestUtils.getFSDataset(dn);
     if (!(dataSet instanceof SimulatedFSDataset)) {
       throw new IOException("injectBlocks is valid only for SimilatedFSDataset");
     }
@@ -1821,7 +1840,7 @@ public class MiniDFSCluster {
       throw new IndexOutOfBoundsException();
     }
     final DataNode dn = dataNodes.get(dataNodeIndex).datanode;
-    final FSDatasetInterface<?> dataSet = DataNodeTestUtils.getFSDataset(dn);
+    final FsDatasetSpi<?> dataSet = DataNodeTestUtils.getFSDataset(dn);
     if (!(dataSet instanceof SimulatedFSDataset)) {
       throw new IOException("injectBlocks is valid only for SimilatedFSDataset");
     }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestFileCreation.java

@@ -60,8 +60,8 @@ import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.server.datanode.DataNode;
 import org.apache.hadoop.hdfs.server.datanode.DataNodeTestUtils;
-import org.apache.hadoop.hdfs.server.datanode.FSDatasetInterface;
 import org.apache.hadoop.hdfs.server.datanode.SimulatedFSDataset;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
 import org.apache.hadoop.hdfs.server.namenode.LeaseManager;
 import org.apache.hadoop.io.IOUtils;
@@ -211,7 +211,7 @@ public class TestFileCreation extends junit.framework.TestCase {
       // can't check capacities for real storage since the OS file system may be changing under us.
       if (simulatedStorage) {
         DataNode dn = cluster.getDataNodes().get(0);
-        FSDatasetInterface<?> dataset = DataNodeTestUtils.getFSDataset(dn);
+        FsDatasetSpi<?> dataset = DataNodeTestUtils.getFSDataset(dn);
         assertEquals(fileSize, dataset.getDfsUsed());
         assertEquals(SimulatedFSDataset.DEFAULT_CAPACITY-fileSize,
             dataset.getRemaining());

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java

@@ -24,6 +24,7 @@ import java.io.IOException;
 
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeRegistration;
 
 /**
@@ -48,7 +49,7 @@ public class DataNodeTestUtils {
    * 
    * @return the fsdataset that stores the blocks
    */
-  public static FSDatasetInterface<?> getFSDataset(DataNode dn) {
+  public static FsDatasetSpi<?> getFSDataset(DataNode dn) {
     return dn.getFSDataset();
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java

@@ -39,10 +39,12 @@ import org.apache.hadoop.hdfs.protocol.BlockLocalPathInfo;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.ReplicaState;
 import org.apache.hadoop.hdfs.server.datanode.FSDataset.FSVolumeSet;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.LengthInputStream;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.ReplicaInputStreams;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.ReplicaOutputStreams;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.RollingLogs;
 import org.apache.hadoop.hdfs.server.datanode.metrics.FSDatasetMBean;
 import org.apache.hadoop.hdfs.server.protocol.BlockRecoveryCommand.RecoveringBlock;
 import org.apache.hadoop.hdfs.server.protocol.ReplicaRecoveryInfo;
@@ -65,10 +67,10 @@ import org.apache.hadoop.util.DiskChecker.DiskErrorException;
  * 
  * Note the synchronization is coarse grained - it is at each method. 
  */
-public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
+public class SimulatedFSDataset implements FsDatasetSpi<FsVolumeSpi> {
-  static class Factory extends FSDatasetInterface.Factory<SimulatedFSDataset> {
+  static class Factory extends FsDatasetSpi.Factory<SimulatedFSDataset> {
     @Override
-    public SimulatedFSDataset createFSDatasetInterface(DataNode datanode,
+    public SimulatedFSDataset newInstance(DataNode datanode,
         DataStorage storage, Configuration conf) throws IOException {
       return new SimulatedFSDataset(datanode, storage, conf);
     }
@@ -427,7 +429,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return map;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized void finalizeBlock(ExtendedBlock b) throws IOException {
     final Map<Block, BInfo> map = getMap(b.getBlockPoolId());
     BInfo binfo = map.get(b.getLocalBlock());
@@ -437,7 +439,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     binfo.finalizeBlock(b.getBlockPoolId(), b.getNumBytes());
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized void unfinalizeBlock(ExtendedBlock b) {
     if (isValidRbw(b)) {
       blockMap.remove(b.getLocalBlock());
@@ -483,7 +485,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return storage.getNumFailedVolumes();
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized long getLength(ExtendedBlock b) throws IOException {
     final Map<Block, BInfo> map = getMap(b.getBlockPoolId());
     BInfo binfo = map.get(b.getLocalBlock());
@@ -513,7 +515,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return r == null? "null": r.toString();
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public Block getStoredBlock(String bpid, long blkid) throws IOException {
     final Map<Block, BInfo> map = blockMap.get(bpid);
     if (map != null) {
@@ -526,7 +528,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return null;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized void invalidate(String bpid, Block[] invalidBlks)
       throws IOException {
     boolean error = false;
@@ -557,12 +559,12 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return map == null? null: map.get(b.getLocalBlock());
   }
 
-  @Override // {@link FSDatasetInterface}
+  @Override // {@link FsDatasetSpi}
   public boolean contains(ExtendedBlock block) {
     return getBInfo(block) != null;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized boolean isValidBlock(ExtendedBlock b) {
     final BInfo binfo = getBInfo(b);
     return binfo != null && binfo.isFinalized();
@@ -580,7 +582,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return getStorageInfo();
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface append(ExtendedBlock b,
       long newGS, long expectedBlockLen) throws IOException {
     final Map<Block, BInfo> map = getMap(b.getBlockPoolId());
@@ -593,7 +595,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return binfo;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface recoverAppend(ExtendedBlock b,
       long newGS, long expectedBlockLen) throws IOException {
     final Map<Block, BInfo> map = getMap(b.getBlockPoolId());
@@ -611,7 +613,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return binfo;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void recoverClose(ExtendedBlock b, long newGS, long expectedBlockLen)
       throws IOException {
     final Map<Block, BInfo> map = getMap(b.getBlockPoolId());
@@ -628,7 +630,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     map.put(binfo.theBlock, binfo);
   }
   
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface recoverRbw(ExtendedBlock b,
       long newGS, long minBytesRcvd, long maxBytesRcvd) throws IOException {
     final Map<Block, BInfo> map = getMap(b.getBlockPoolId());
@@ -647,13 +649,13 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return binfo;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface createRbw(ExtendedBlock b) 
   throws IOException {
     return createTemporary(b);
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized ReplicaInPipelineInterface createTemporary(ExtendedBlock b)
       throws IOException {
     if (isValidBlock(b)) {
@@ -681,7 +683,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     return binfo.getIStream();
   }
   
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized InputStream getBlockInputStream(ExtendedBlock b,
       long seekOffset) throws IOException {
     InputStream result = getBlockInputStream(b);
@@ -690,13 +692,13 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
   }
 
   /** Not supported */
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public ReplicaInputStreams getTmpInputStreams(ExtendedBlock b, long blkoff,
       long ckoff) throws IOException {
     throw new IOException("Not supported");
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized LengthInputStream getMetaDataInputStream(ExtendedBlock b
       ) throws IOException {
     final Map<Block, BInfo> map = getMap(b.getBlockPoolId());
@@ -717,7 +719,7 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
     // nothing to check for simulated data set
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public synchronized void adjustCrcChannelPosition(ExtendedBlock b,
                                               ReplicaOutputStreams stream, 
                                               int checksumSize)
@@ -902,32 +904,32 @@ public class SimulatedFSDataset implements FSDatasetInterface<FsVolumeSpi> {
         binfo.isFinalized()?ReplicaState.FINALIZED : ReplicaState.RBW);
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public String updateReplicaUnderRecovery(ExtendedBlock oldBlock,
                                         long recoveryId,
                                         long newlength) {
     return storageId;
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public long getReplicaVisibleLength(ExtendedBlock block) {
     return block.getNumBytes();
   }
 
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void addBlockPool(String bpid, Configuration conf) {
     Map<Block, BInfo> map = new HashMap<Block, BInfo>();
     blockMap.put(bpid, map);
     storage.addBlockPool(bpid);
   }
   
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void shutdownBlockPool(String bpid) {
     blockMap.remove(bpid);
     storage.removeBlockPool(bpid);
   }
   
-  @Override // FSDatasetInterface
+  @Override // FsDatasetSpi
   public void deleteBlockPool(String bpid, boolean force) {
      return;
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestBPOfferService.java

@@ -33,6 +33,7 @@ import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolClientSideTranslatorPB;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.metrics.DataNodeMetrics;
 import org.apache.hadoop.hdfs.server.protocol.BlockCommand;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeCommand;
@@ -77,7 +78,7 @@ public class TestBPOfferService {
   private NNHAStatusHeartbeat[] mockHaStatuses = new NNHAStatusHeartbeat[2];
   private int heartbeatCounts[] = new int[2];
   private DataNode mockDn;
-  private FSDatasetInterface<?> mockFSDataset;
+  private FsDatasetSpi<?> mockFSDataset;
   
   @Before
   public void setupMocks() throws Exception {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestSimulatedFSDataset.java

@@ -29,6 +29,7 @@ import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.BlockListAsLongs;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.ReplicaOutputStreams;
 import org.apache.hadoop.util.DataChecksum;
 
@@ -88,12 +89,12 @@ public class TestSimulatedFSDataset extends TestCase {
   
   public void testFSDatasetFactory() {
     final Configuration conf = new Configuration();
-    FSDatasetInterface.Factory<?> f = FSDatasetInterface.Factory.getFactory(conf);
+    FsDatasetSpi.Factory<?> f = FsDatasetSpi.Factory.getFactory(conf);
     assertEquals(FSDataset.Factory.class, f.getClass());
     assertFalse(f.isSimulated());
 
     SimulatedFSDataset.setFactory(conf);
-    FSDatasetInterface.Factory<?> s = FSDatasetInterface.Factory.getFactory(conf);
+    FsDatasetSpi.Factory<?> s = FsDatasetSpi.Factory.getFactory(conf);
     assertEquals(SimulatedFSDataset.Factory.class, s.getClass());
     assertTrue(s.isSimulated());
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/TestRoundRobinVolumeChoosingPolicy.java

@@ -15,20 +15,19 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.hadoop.hdfs.server.datanode;
+package org.apache.hadoop.hdfs.server.datanode.fsdataset;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 import org.apache.hadoop.util.DiskChecker.DiskOutOfSpaceException;
 import org.apache.hadoop.util.ReflectionUtils;
 import org.junit.Assert;
 import org.junit.Test;
 import org.mockito.Mockito;
 
-public class TestRoundRobinVolumesPolicy {
+public class TestRoundRobinVolumeChoosingPolicy {
 
   // Test the Round-Robin block-volume choosing algorithm.
   @Test
@@ -44,9 +43,8 @@ public class TestRoundRobinVolumesPolicy {
     Mockito.when(volumes.get(1).getAvailable()).thenReturn(200L);
 
     @SuppressWarnings("unchecked")
-    final RoundRobinVolumesPolicy<FsVolumeSpi> policy = 
+    final RoundRobinVolumeChoosingPolicy<FsVolumeSpi> policy = 
-        (RoundRobinVolumesPolicy<FsVolumeSpi>)ReflectionUtils.newInstance(
+        ReflectionUtils.newInstance(RoundRobinVolumeChoosingPolicy.class, null);
-            RoundRobinVolumesPolicy.class, null);
     
     // Test two rounds of round-robin choosing
     Assert.assertEquals(volumes.get(0), policy.chooseVolume(volumes, 0));
@@ -67,10 +65,10 @@ public class TestRoundRobinVolumesPolicy {
     }
   }
   
-  // ChooseVolume should throw DiskOutOfSpaceException with volume and block sizes in exception message.
+  // ChooseVolume should throw DiskOutOfSpaceException
+  // with volume and block sizes in exception message.
   @Test
-  public void testRRPolicyExceptionMessage()
+  public void testRRPolicyExceptionMessage() throws Exception {
-      throws Exception {
     final List<FsVolumeSpi> volumes = new ArrayList<FsVolumeSpi>();
 
     // First volume, with 500 bytes of space.
@@ -81,18 +79,17 @@ public class TestRoundRobinVolumesPolicy {
     volumes.add(Mockito.mock(FsVolumeSpi.class));
     Mockito.when(volumes.get(1).getAvailable()).thenReturn(600L);
 
-    final RoundRobinVolumesPolicy<FsVolumeSpi> policy
+    final RoundRobinVolumeChoosingPolicy<FsVolumeSpi> policy
-        = new RoundRobinVolumesPolicy<FsVolumeSpi>();
+        = new RoundRobinVolumeChoosingPolicy<FsVolumeSpi>();
     int blockSize = 700;
     try {
       policy.chooseVolume(volumes, blockSize);
       Assert.fail("expected to throw DiskOutOfSpaceException");
-    } catch (DiskOutOfSpaceException e) {
+    } catch(DiskOutOfSpaceException e) {
-      Assert
+      Assert.assertEquals("Not returnig the expected message",
-          .assertEquals(
+          "Out of space: The volume with the most available space (=" + 600
-              "Not returnig the expected message",
+              + " B) is less than the block size (=" + blockSize + " B).",
-              "Insufficient space for an additional block. Volume with the most available space has 600 bytes free, configured block size is " + blockSize, e
+          e.getMessage());
-                  .getMessage());
     }
   }