import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Helper method to combine a list of {@link LocatedBlock} with associated
 * {@link VolumeId} information to form a list of {@link BlockStorageLocation}
 * .
 */
static BlockStorageLocation[] convertToVolumeBlockLocations(
    List<LocatedBlock> blocks, 
    Map<LocatedBlock, List<VolumeId>> blockVolumeIds) throws IOException {
  // Construct the final return value of VolumeBlockLocation[]
  BlockLocation[] locations = DFSUtil.locatedBlocks2Locations(blocks);
  List<BlockStorageLocation> volumeBlockLocs = 
      new ArrayList<BlockStorageLocation>(locations.length);
  for (int i = 0; i < locations.length; i++) {
    LocatedBlock locBlock = blocks.get(i);
    List<VolumeId> volumeIds = blockVolumeIds.get(locBlock);
    BlockStorageLocation bsLoc = new BlockStorageLocation(locations[i], 
        volumeIds.toArray(new VolumeId[0]));
    volumeBlockLocs.add(bsLoc);
  }
  return volumeBlockLocs.toArray(new BlockStorageLocation[] {});
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Helper method to combine a list of {@link LocatedBlock} with associated
 * {@link VolumeId} information to form a list of {@link
 * BlockStorageLocation}
 * .
 */
static BlockStorageLocation[] convertToVolumeBlockLocations(
    List<LocatedBlock> blocks,
    Map<LocatedBlock, List<VolumeId>> blockVolumeIds) throws IOException {
  // Construct the final return value of VolumeBlockLocation[]
  BlockLocation[] locations = DFSUtil.locatedBlocks2Locations(blocks);
  List<BlockStorageLocation> volumeBlockLocs =
      new ArrayList<>(locations.length);
  for (int i = 0; i < locations.length; i++) {
    LocatedBlock locBlock = blocks.get(i);
    List<VolumeId> volumeIds = blockVolumeIds.get(locBlock);
    BlockStorageLocation bsLoc = new BlockStorageLocation(locations[i],
        volumeIds.toArray(new VolumeId[0]));
    volumeBlockLocs.add(bsLoc);
  }
  return volumeBlockLocs.toArray(new BlockStorageLocation[]{});
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
private void printBlockMetadata(BlockLocation blockLocation, String[] dataDirs) throws IOException {

		System.out.println("	Offset: " + blockLocation.getOffset());
		System.out.println("	Length: " + blockLocation.getLength());

		String[] cachedHosts = blockLocation.getCachedHosts();
		if (cachedHosts.length == 0) {
			System.out.println("	No cached hosts");
		}

		System.out.println("	Replicas:");
		VolumeId[] volumeIds = blockLocation instanceof BlockStorageLocation ?
				(((BlockStorageLocation) blockLocation).getVolumeIds()) : null;
		String[] hosts = blockLocation.getHosts();
		String[] names = blockLocation.getNames();
		String[] topologyPaths = blockLocation.getTopologyPaths();
		for (int i = 0; i < topologyPaths.length; i++) {
			int diskId = volumeIds != null ? DistributedFileSystemMetadata.getDiskId(volumeIds[i]) : -1;
			
			System.out.println("		Replica (" + i + "):");
			System.out.println("			Host: " + hosts[i]);
			
			if(diskId == -1)
				System.out.println("			DiskId: unknown");
			else if(dataDirs != null && diskId < dataDirs.length)
				System.out.println("			Location: " + dataDirs[diskId] + " (DiskId: " + diskId + ")");
			else
				System.out.println("			DiskId: " + diskId);
			
			System.out.println("			Name: " + names[i]);
			System.out.println("			TopologyPaths: " + topologyPaths[i]);
		}

		if (cachedHosts.length > 0) {
			System.out.println("	Cached hosts:");
			for (String cachedHost : cachedHosts) {
				System.out.println("		Host: " + cachedHost);
			}
		}
	}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
@Test
public void computeHostsDiskIdsCount() throws IOException{
	List<BlockLocation> blockStorageLocations = new LinkedList<>();
	blockStorageLocations.add(new BlockStorageLocation(
			new BlockLocation(null, new String[]{"host1", "host2"}, 0, 0), 
			new VolumeId[]{new TVolumeId("3"), new TVolumeId("4")}));
	blockStorageLocations.add(new BlockStorageLocation(
			new BlockLocation(null, new String[]{"host2", "host3"}, 0, 0), 
			new VolumeId[]{new TVolumeId("4"), new TVolumeId("5")}));
	blockStorageLocations.add(new BlockStorageLocation(
			new BlockLocation(null, new String[]{"host10", "host2"}, 0, 0), 
			new VolumeId[]{new TVolumeId("3"), new TVolumeId("4")}));
	blockStorageLocations.add(new BlockStorageLocation(
			new BlockLocation(null, new String[]{"host10", "host3"}, 0, 0), 
			new VolumeId[]{new TVolumeId("8"), new TVolumeId("5")}));
	blockStorageLocations.add(new BlockLocation(null, new String[]{"host10", "host3", "host3"}, 0, 0));
			
	HashMap<String, HashMap<Integer, Integer>> hosts_diskids = 
			DistributedFileSystemMetadata.computeHostsDiskIdsCount(blockStorageLocations);
	
	Assert.assertEquals(1, hosts_diskids.get("host1").get(3).intValue());
	Assert.assertEquals(3, hosts_diskids.get("host2").get(4).intValue());
	Assert.assertEquals(2, hosts_diskids.get("host3").get(5).intValue());
	Assert.assertEquals(2, hosts_diskids.get("host3").get(-1).intValue());
	Assert.assertEquals(1, hosts_diskids.get("host10").get(3).intValue());
	Assert.assertEquals(1, hosts_diskids.get("host10").get(8).intValue());
	Assert.assertEquals(1, hosts_diskids.get("host10").get(-1).intValue());
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Tests error paths for
 * {@link DistributedFileSystem#getFileBlockStorageLocations(java.util.List)}
 */
@Test
public void testGetFileBlockStorageLocationsError() throws Exception {
  final Configuration conf = getTestConfiguration();
  conf.setBoolean(DFSConfigKeys.DFS_HDFS_BLOCKS_METADATA_ENABLED,
      true);
  final MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
      .numDataNodes(2).build();
  try {
    cluster.getDataNodes();
    DistributedFileSystem fs = cluster.getFileSystem();
    // Create a file
    Path tmpFile = new Path("/tmpfile1.dat");
    DFSTestUtil.createFile(fs, tmpFile, 1024, (short) 2, 0xDEADDEADl);
    // Get locations of blocks of the file
    BlockLocation[] blockLocs = fs.getFileBlockLocations(tmpFile, 0, 1024);
    // Stop a datanode to simulate a failure
    cluster.stopDataNode(0);
    // Fetch VolumeBlockLocations
    BlockStorageLocation[] locs = fs.getFileBlockStorageLocations(Arrays
        .asList(blockLocs));

    assertEquals("Expected one HdfsBlockLocation for one 1-block file", 1,
        locs.length);

    for (BlockStorageLocation l : locs) {
      assertEquals("Expected two replicas for each block", 2,
          l.getVolumeIds().length);
      assertTrue("Expected one valid and one invalid replica",
          (l.getVolumeIds()[0].isValid()) ^ (l.getVolumeIds()[1].isValid()));
    }
  } finally {
    cluster.shutdown();
  }
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Tests error paths for
 * {@link DistributedFileSystem#getFileBlockStorageLocations(java.util.List)}
 */
@Test
public void testGetFileBlockStorageLocationsError() throws Exception {
  final Configuration conf = getTestConfiguration();
  conf.setBoolean(DFSConfigKeys.DFS_HDFS_BLOCKS_METADATA_ENABLED, true);
  final MiniDFSCluster cluster =
      new MiniDFSCluster.Builder(conf).numDataNodes(2).build();
  cluster.getDataNodes();
  DistributedFileSystem fs = cluster.getFileSystem();
  // Create a file
  Path tmpFile = new Path("/tmpfile1.dat");
  DFSTestUtil.createFile(fs, tmpFile, 1024, (short) 2, 0xDEADDEADl);
  // Get locations of blocks of the file
  BlockLocation[] blockLocs = fs.getFileBlockLocations(tmpFile, 0, 1024);
  // Stop a datanode to simulate a failure
  cluster.stopDataNode(0);
  // Fetch VolumeBlockLocations
  BlockStorageLocation[] locs =
      fs.getFileBlockStorageLocations(Arrays.asList(blockLocs));

  assertEquals("Expected one HdfsBlockLocation for one 1-block file", 1,
      locs.length);

  for (BlockStorageLocation l : locs) {
    assertEquals("Expected two replicas for each block", 2,
        l.getVolumeIds().length);
    assertTrue("Expected one valid and one invalid replica",
        (l.getVolumeIds()[0].isValid()) ^ (l.getVolumeIds()[1].isValid()));
  }
  cluster.shutdown();
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Get block location information about a list of {@link HdfsBlockLocation}.
 * Used by {@link DistributedFileSystem#getFileBlockStorageLocations(List)} to
 * get {@link BlockStorageLocation}s for blocks returned by
 * {@link DistributedFileSystem#getFileBlockLocations(org.apache.hadoop.fs.FileStatus, long, long)}
 * .
 * 
 * This is done by making a round of RPCs to the associated datanodes, asking
 * the volume of each block replica. The returned array of
 * {@link BlockStorageLocation} expose this information as a
 * {@link VolumeId}.
 * 
 * @param blockLocations
 *          target blocks on which to query volume location information
 * @return volumeBlockLocations original block array augmented with additional
 *         volume location information for each replica.
 */
public BlockStorageLocation[] getBlockStorageLocations(
    List<BlockLocation> blockLocations) throws IOException,
    UnsupportedOperationException, InvalidBlockTokenException {
  if (!getConf().getHdfsBlocksMetadataEnabled) {
    throw new UnsupportedOperationException("Datanode-side support for " +
        "getVolumeBlockLocations() must also be enabled in the client " +
        "configuration.");
  }
  // Downcast blockLocations and fetch out required LocatedBlock(s)
  List<LocatedBlock> blocks = new ArrayList<LocatedBlock>();
  for (BlockLocation loc : blockLocations) {
    if (!(loc instanceof HdfsBlockLocation)) {
      throw new ClassCastException("DFSClient#getVolumeBlockLocations " +
          "expected to be passed HdfsBlockLocations");
    }
    HdfsBlockLocation hdfsLoc = (HdfsBlockLocation) loc;
    blocks.add(hdfsLoc.getLocatedBlock());
  }
  
  // Re-group the LocatedBlocks to be grouped by datanodes, with the values
  // a list of the LocatedBlocks on the datanode.
  Map<DatanodeInfo, List<LocatedBlock>> datanodeBlocks = 
      new LinkedHashMap<DatanodeInfo, List<LocatedBlock>>();
  for (LocatedBlock b : blocks) {
    for (DatanodeInfo info : b.getLocations()) {
      if (!datanodeBlocks.containsKey(info)) {
        datanodeBlocks.put(info, new ArrayList<LocatedBlock>());
      }
      List<LocatedBlock> l = datanodeBlocks.get(info);
      l.add(b);
    }
  }
      
  // Make RPCs to the datanodes to get volume locations for its replicas
  TraceScope scope =
    Trace.startSpan("getBlockStorageLocations", traceSampler);
  Map<DatanodeInfo, HdfsBlocksMetadata> metadatas;
  try {
    metadatas = BlockStorageLocationUtil.
        queryDatanodesForHdfsBlocksMetadata(conf, datanodeBlocks,
            getConf().getFileBlockStorageLocationsNumThreads,
            getConf().getFileBlockStorageLocationsTimeoutMs,
            getConf().connectToDnViaHostname);
    if (LOG.isTraceEnabled()) {
      LOG.trace("metadata returned: "
          + Joiner.on("\n").withKeyValueSeparator("=").join(metadatas));
    }
  } finally {
    scope.close();
  }
  
  // Regroup the returned VolumeId metadata to again be grouped by
  // LocatedBlock rather than by datanode
  Map<LocatedBlock, List<VolumeId>> blockVolumeIds = BlockStorageLocationUtil
      .associateVolumeIdsWithBlocks(blocks, metadatas);
  
  // Combine original BlockLocations with new VolumeId information
  BlockStorageLocation[] volumeBlockLocations = BlockStorageLocationUtil
      .convertToVolumeBlockLocations(blocks, blockVolumeIds);

  return volumeBlockLocations;
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
public LinkedList<BlockLocation> getBlockLocations(Path path) throws IOException {
	LOG.info("Collecting block locations...");
	
	LinkedList<BlockLocation> blockLocations = new LinkedList<BlockLocation>();
	RemoteIterator<LocatedFileStatus> statuses = listFiles(path, true);
	int hasNextCode = hasNextCode(statuses);
	while(hasNextCode > 0){
		if(hasNextCode > 1){
			hasNextCode = hasNextCode(statuses);
			continue;
		}
		
		LocatedFileStatus fileStatus = statuses.next();
		
		if(fileStatus.isFile()){
			BlockLocation[] blockLocations_tmp = getFileBlockLocations(fileStatus, 0, fileStatus.getLen());
			
			blockLocations.addAll(Arrays.asList(blockLocations_tmp));
		}
		
		int size = blockLocations.size();
		if(size > 0 && size % 5000 == 0)
			LOG.info("Collected " + size + " locations. Still in progress...");
		
		if(size >= MAX_NUMBER_OF_LOCATIONS){
			LOG.info("Reached max number of locations to collect. The amount will be representative enough.");
			break;
		}
		
		hasNextCode = hasNextCode(statuses);
	}
	LOG.info("Collected " + blockLocations.size() + " locations.");
	
	if(isHdfsBlocksMetadataEnabled()){
		BlockStorageLocation[] blockStorageLocations = getFileBlockStorageLocations(blockLocations);
		
		blockLocations.clear();
		blockLocations.addAll(Arrays.asList(blockStorageLocations));
	}else{
		LOG.error("VolumnId/DiskId can not be collected since "
				+ "dfs.datanode.hdfs-blocks-metadata.enabled is not enabled.");
	}
	
	return blockLocations;
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Get block location information about a list of {@link HdfsBlockLocation}.
 * Used by {@link DistributedFileSystem#getFileBlockStorageLocations(List)} to
 * get {@link BlockStorageLocation}s for blocks returned by
 * {@link DistributedFileSystem#getFileBlockLocations(org.apache.hadoop.fs.FileStatus, long, long)}
 * .
 * 
 * This is done by making a round of RPCs to the associated datanodes, asking
 * the volume of each block replica. The returned array of
 * {@link BlockStorageLocation} expose this information as a
 * {@link VolumeId}.
 * 
 * @param blockLocations
 *          target blocks on which to query volume location information
 * @return volumeBlockLocations original block array augmented with additional
 *         volume location information for each replica.
 */
public BlockStorageLocation[] getBlockStorageLocations(
    List<BlockLocation> blockLocations) throws IOException,
    UnsupportedOperationException, InvalidBlockTokenException {
  if (!getConf().getHdfsBlocksMetadataEnabled) {
    throw new UnsupportedOperationException("Datanode-side support for " +
        "getVolumeBlockLocations() must also be enabled in the client " +
        "configuration.");
  }
  // Downcast blockLocations and fetch out required LocatedBlock(s)
  List<LocatedBlock> blocks = new ArrayList<LocatedBlock>();
  for (BlockLocation loc : blockLocations) {
    if (!(loc instanceof HdfsBlockLocation)) {
      throw new ClassCastException("DFSClient#getVolumeBlockLocations " +
          "expected to be passed HdfsBlockLocations");
    }
    HdfsBlockLocation hdfsLoc = (HdfsBlockLocation) loc;
    blocks.add(hdfsLoc.getLocatedBlock());
  }
  
  // Re-group the LocatedBlocks to be grouped by datanodes, with the values
  // a list of the LocatedBlocks on the datanode.
  Map<DatanodeInfo, List<LocatedBlock>> datanodeBlocks = 
      new LinkedHashMap<DatanodeInfo, List<LocatedBlock>>();
  for (LocatedBlock b : blocks) {
    for (DatanodeInfo info : b.getLocations()) {
      if (!datanodeBlocks.containsKey(info)) {
        datanodeBlocks.put(info, new ArrayList<LocatedBlock>());
      }
      List<LocatedBlock> l = datanodeBlocks.get(info);
      l.add(b);
    }
  }
      
  // Make RPCs to the datanodes to get volume locations for its replicas
  Map<DatanodeInfo, HdfsBlocksMetadata> metadatas = BlockStorageLocationUtil
      .queryDatanodesForHdfsBlocksMetadata(conf, datanodeBlocks,
          getConf().getFileBlockStorageLocationsNumThreads,
          getConf().getFileBlockStorageLocationsTimeoutMs,
          getConf().connectToDnViaHostname);
  
  if (LOG.isTraceEnabled()) {
    LOG.trace("metadata returned: "
        + Joiner.on("\n").withKeyValueSeparator("=").join(metadatas));
  }
  
  // Regroup the returned VolumeId metadata to again be grouped by
  // LocatedBlock rather than by datanode
  Map<LocatedBlock, List<VolumeId>> blockVolumeIds = BlockStorageLocationUtil
      .associateVolumeIdsWithBlocks(blocks, metadatas);
  
  // Combine original BlockLocations with new VolumeId information
  BlockStorageLocation[] volumeBlockLocations = BlockStorageLocationUtil
      .convertToVolumeBlockLocations(blocks, blockVolumeIds);

  return volumeBlockLocations;
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Get block location information about a list of {@link HdfsBlockLocation}.
 * Used by {@link DistributedFileSystem#getFileBlockStorageLocations(List)} to
 * get {@link BlockStorageLocation}s for blocks returned by
 * {@link DistributedFileSystem#getFileBlockLocations(org.apache.hadoop.fs.FileStatus, long, long)}
 * .
 * 
 * This is done by making a round of RPCs to the associated datanodes, asking
 * the volume of each block replica. The returned array of
 * {@link BlockStorageLocation} expose this information as a
 * {@link VolumeId}.
 * 
 * @param blockLocations
 *          target blocks on which to query volume location information
 * @return volumeBlockLocations original block array augmented with additional
 *         volume location information for each replica.
 */
public BlockStorageLocation[] getBlockStorageLocations(
    List<BlockLocation> blockLocations) throws IOException,
    UnsupportedOperationException, InvalidBlockTokenException {
  if (!getConf().getHdfsBlocksMetadataEnabled) {
    throw new UnsupportedOperationException("Datanode-side support for " +
        "getVolumeBlockLocations() must also be enabled in the client " +
        "configuration.");
  }
  // Downcast blockLocations and fetch out required LocatedBlock(s)
  List<LocatedBlock> blocks = new ArrayList<LocatedBlock>();
  for (BlockLocation loc : blockLocations) {
    if (!(loc instanceof HdfsBlockLocation)) {
      throw new ClassCastException("DFSClient#getVolumeBlockLocations " +
          "expected to be passed HdfsBlockLocations");
    }
    HdfsBlockLocation hdfsLoc = (HdfsBlockLocation) loc;
    blocks.add(hdfsLoc.getLocatedBlock());
  }
  
  // Re-group the LocatedBlocks to be grouped by datanodes, with the values
  // a list of the LocatedBlocks on the datanode.
  Map<DatanodeInfo, List<LocatedBlock>> datanodeBlocks = 
      new LinkedHashMap<DatanodeInfo, List<LocatedBlock>>();
  for (LocatedBlock b : blocks) {
    for (DatanodeInfo info : b.getLocations()) {
      if (!datanodeBlocks.containsKey(info)) {
        datanodeBlocks.put(info, new ArrayList<LocatedBlock>());
      }
      List<LocatedBlock> l = datanodeBlocks.get(info);
      l.add(b);
    }
  }
      
  // Make RPCs to the datanodes to get volume locations for its replicas
  List<HdfsBlocksMetadata> metadatas = BlockStorageLocationUtil
      .queryDatanodesForHdfsBlocksMetadata(conf, datanodeBlocks,
          getConf().getFileBlockStorageLocationsNumThreads,
          getConf().getFileBlockStorageLocationsTimeout,
          getConf().connectToDnViaHostname);
  
  // Regroup the returned VolumeId metadata to again be grouped by
  // LocatedBlock rather than by datanode
  Map<LocatedBlock, List<VolumeId>> blockVolumeIds = BlockStorageLocationUtil
      .associateVolumeIdsWithBlocks(blocks, datanodeBlocks, metadatas);
  
  // Combine original BlockLocations with new VolumeId information
  BlockStorageLocation[] volumeBlockLocations = BlockStorageLocationUtil
      .convertToVolumeBlockLocations(blocks, blockVolumeIds);

  return volumeBlockLocations;
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Get block location information about a list of {@link HdfsBlockLocation}.
 * Used by {@link DistributedFileSystem#getFileBlockStorageLocations(List)}
 * to
 * get {@link BlockStorageLocation}s for blocks returned by
 * {@link DistributedFileSystem#getFileBlockLocations(org.apache.hadoop.fs.FileStatus,
 * long, long)}
 * .
 * <p/>
 * This is done by making a round of RPCs to the associated datanodes, asking
 * the volume of each block replica. The returned array of
 * {@link BlockStorageLocation} expose this information as a
 * {@link VolumeId}.
 *
 * @param blockLocations
 *     target blocks on which to query volume location information
 * @return volumeBlockLocations original block array augmented with additional
 * volume location information for each replica.
 */
public BlockStorageLocation[] getBlockStorageLocations(
    List<BlockLocation> blockLocations)
    throws IOException, UnsupportedOperationException,
    InvalidBlockTokenException {
  if (!getConf().getHdfsBlocksMetadataEnabled) {
    throw new UnsupportedOperationException("Datanode-side support for " +
        "getVolumeBlockLocations() must also be enabled in the client " +
        "configuration.");
  }
  // Downcast blockLocations and fetch out required LocatedBlock(s)
  List<LocatedBlock> blocks = new ArrayList<>();
  for (BlockLocation loc : blockLocations) {
    if (!(loc instanceof HdfsBlockLocation)) {
      throw new ClassCastException("DFSClient#getVolumeBlockLocations " +
          "expected to be passed HdfsBlockLocations");
    }
    HdfsBlockLocation hdfsLoc = (HdfsBlockLocation) loc;
    blocks.add(hdfsLoc.getLocatedBlock());
  }
  
  // Re-group the LocatedBlocks to be grouped by datanodes, with the values
  // a list of the LocatedBlocks on the datanode.
  Map<DatanodeInfo, List<LocatedBlock>> datanodeBlocks =
      new LinkedHashMap<>();
  for (LocatedBlock b : blocks) {
    for (DatanodeInfo info : b.getLocations()) {
      if (!datanodeBlocks.containsKey(info)) {
        datanodeBlocks.put(info, new ArrayList<LocatedBlock>());
      }
      List<LocatedBlock> l = datanodeBlocks.get(info);
      l.add(b);
    }
  }

  // Make RPCs to the datanodes to get volume locations for its replicas
  List<HdfsBlocksMetadata> metadatas = BlockStorageLocationUtil
      .queryDatanodesForHdfsBlocksMetadata(conf, datanodeBlocks,
          getConf().getFileBlockStorageLocationsNumThreads,
          getConf().getFileBlockStorageLocationsTimeout,
          getConf().connectToDnViaHostname);
  
  // Regroup the returned VolumeId metadata to again be grouped by
  // LocatedBlock rather than by datanode
  Map<LocatedBlock, List<VolumeId>> blockVolumeIds = BlockStorageLocationUtil
      .associateVolumeIdsWithBlocks(blocks, datanodeBlocks, metadatas);
  
  // Combine original BlockLocations with new VolumeId information
  BlockStorageLocation[] volumeBlockLocations = BlockStorageLocationUtil
      .convertToVolumeBlockLocations(blocks, blockVolumeIds);

  return volumeBlockLocations;
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Used to query storage location information for a list of blocks. This list
 * of blocks is normally constructed via a series of calls to
 * {@link DistributedFileSystem#getFileBlockLocations(Path, long, long)} to
 * get the blocks for ranges of a file.
 * 
 * The returned array of {@link BlockStorageLocation} augments
 * {@link BlockLocation} with a {@link VolumeId} per block replica. The
 * VolumeId specifies the volume on the datanode on which the replica resides.
 * The VolumeId associated with a replica may be null because volume
 * information can be unavailable if the corresponding datanode is down or
 * if the requested block is not found.
 * 
 * This API is unstable, and datanode-side support is disabled by default. It
 * can be enabled by setting "dfs.datanode.hdfs-blocks-metadata.enabled" to
 * true.
 * 
 * @param blocks
 *          List of target BlockLocations to query volume location information
 * @return volumeBlockLocations Augmented array of
 *         {@link BlockStorageLocation}s containing additional volume location
 *         information for each replica of each block.
 */
@InterfaceStability.Unstable
public BlockStorageLocation[] getFileBlockStorageLocations(
    List<BlockLocation> blocks) throws IOException, 
    UnsupportedOperationException, InvalidBlockTokenException {
  return dfs.getBlockStorageLocations(blocks);
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Used to query storage location information for a list of blocks. This list
 * of blocks is normally constructed via a series of calls to
 * {@link DistributedFileSystem#getFileBlockLocations(Path, long, long)} to
 * get the blocks for ranges of a file.
 * 
 * The returned array of {@link BlockStorageLocation} augments
 * {@link BlockLocation} with a {@link VolumeId} per block replica. The
 * VolumeId specifies the volume on the datanode on which the replica resides.
 * The VolumeId has to be checked via {@link VolumeId#isValid()} before being
 * used because volume information can be unavailable if the corresponding
 * datanode is down or if the requested block is not found.
 * 
 * This API is unstable, and datanode-side support is disabled by default. It
 * can be enabled by setting "dfs.datanode.hdfs-blocks-metadata.enabled" to
 * true.
 * 
 * @param blocks
 *          List of target BlockLocations to query volume location information
 * @return volumeBlockLocations Augmented array of
 *         {@link BlockStorageLocation}s containing additional volume location
 *         information for each replica of each block.
 */
@InterfaceStability.Unstable
public BlockStorageLocation[] getFileBlockStorageLocations(
    List<BlockLocation> blocks) throws IOException, 
    UnsupportedOperationException, InvalidBlockTokenException {
  return dfs.getBlockStorageLocations(blocks);
}
 

import org.apache.hadoop.fs.BlockStorageLocation; //导入依赖的package包/类
/**
 * Used to query storage location information for a list of blocks. This list
 * of blocks is normally constructed via a series of calls to
 * {@link DistributedFileSystem#getFileBlockLocations(Path, long, long)} to
 * get the blocks for ranges of a file.
 * <p/>
 * The returned array of {@link BlockStorageLocation} augments
 * {@link BlockLocation} with a {@link VolumeId} per block replica. The
 * VolumeId specifies the volume on the datanode on which the replica
 * resides.
 * The VolumeId has to be checked via {@link VolumeId#isValid()} before being
 * used because volume information can be unavailable if the corresponding
 * datanode is down or if the requested block is not found.
 * <p/>
 * This API is unstable, and datanode-side support is disabled by default. It
 * can be enabled by setting "dfs.datanode.hdfs-blocks-metadata.enabled" to
 * true.
 *
 * @param blocks
 *     List of target BlockLocations to query volume location information
 * @return volumeBlockLocations Augmented array of
 * {@link BlockStorageLocation}s containing additional volume location
 * information for each replica of each block.
 */
@InterfaceStability.Unstable
public BlockStorageLocation[] getFileBlockStorageLocations(
    List<BlockLocation> blocks)
    throws IOException, UnsupportedOperationException,
    InvalidBlockTokenException {
  return dfs.getBlockStorageLocations(blocks);
}