import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
boolean isBPDirEmpty(String bpid) throws IOException {
  File volumeCurrentDir = this.getCurrentDir();
  File bpDir = new File(volumeCurrentDir, bpid);
  File bpCurrentDir = new File(bpDir, DataStorage.STORAGE_DIR_CURRENT);
  File finalizedDir = new File(bpCurrentDir,
      DataStorage.STORAGE_DIR_FINALIZED);
  File rbwDir = new File(bpCurrentDir, DataStorage.STORAGE_DIR_RBW);
  if (finalizedDir.exists() && !DatanodeUtil.dirNoFilesRecursive(
      finalizedDir)) {
    return false;
  }
  if (rbwDir.exists() && FileUtil.list(rbwDir).length != 0) {
    return false;
  }
  return true;
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
private static void createUnlinkTmpFile(ReplicaInfo replicaInfo, 
    boolean changeBlockFile, 
    boolean isRename) throws IOException {
  File src;
  if (changeBlockFile) {
    src = replicaInfo.getBlockFile();
  } else {
    src = replicaInfo.getMetaFile();
  }
  File dst = DatanodeUtil.getUnlinkTmpFile(src);
  if (isRename) {
    src.renameTo(dst);
  } else {
    FileInputStream in = new FileInputStream(src);
    try {
      FileOutputStream out = new FileOutputStream(dst);
      try {
        IOUtils.copyBytes(in, out, 1);
      } finally {
        out.close();
      }
    } finally {
      in.close();
    }
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
protected final boolean verifyBlockDeletedFromDir(File dir,
    LocatedBlocks locatedBlocks) {

  for (LocatedBlock lb : locatedBlocks.getLocatedBlocks()) {
    File targetDir =
      DatanodeUtil.idToBlockDir(dir, lb.getBlock().getBlockId());

    File blockFile = new File(targetDir, lb.getBlock().getBlockName());
    if (blockFile.exists()) {
      LOG.warn("blockFile: " + blockFile.getAbsolutePath() +
        " exists after deletion.");
      return false;
    }
    File metaFile = new File(targetDir,
      DatanodeUtil.getMetaName(lb.getBlock().getBlockName(),
        lb.getBlock().getGenerationStamp()));
    if (metaFile.exists()) {
      LOG.warn("metaFile: " + metaFile.getAbsolutePath() +
        " exists after deletion.");
      return false;
    }
  }
  return true;
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
/**
 * Copy the block and meta files for the given block to the given destination.
 * @return the new meta and block files.
 * @throws IOException
 */
static File[] copyBlockFiles(long blockId, long genStamp,
                             File srcMeta, File srcFile, File destRoot)
    throws IOException {
  final File destDir = DatanodeUtil.idToBlockDir(destRoot, blockId);
  final File dstFile = new File(destDir, srcFile.getName());
  final File dstMeta = FsDatasetUtil.getMetaFile(dstFile, genStamp);
  computeChecksum(srcMeta, dstMeta, srcFile);

  try {
    Storage.nativeCopyFileUnbuffered(srcFile, dstFile, true);
  } catch (IOException e) {
    throw new IOException("Failed to copy " + srcFile + " to " + dstFile, e);
  }
  if (LOG.isDebugEnabled()) {
    LOG.debug("Copied " + srcMeta + " to " + dstMeta +
        " and calculated checksum");
    LOG.debug("Copied " + srcFile + " to " + dstFile);
  }
  return new File[] {dstMeta, dstFile};
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
private static void createUnlinkTmpFile(ReplicaInfo replicaInfo,
    boolean changeBlockFile, boolean isRename) throws IOException {
  File src;
  if (changeBlockFile) {
    src = replicaInfo.getBlockFile();
  } else {
    src = replicaInfo.getMetaFile();
  }
  File dst = DatanodeUtil.getUnlinkTmpFile(src);
  if (isRename) {
    src.renameTo(dst);
  } else {
    FileInputStream in = new FileInputStream(src);
    try {
      FileOutputStream out = new FileOutputStream(dst);
      try {
        IOUtils.copyBytes(in, out, 1);
      } finally {
        out.close();
      }
    } finally {
      in.close();
    }
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
static File getOrigFile(File unlinkTmpFile) {
  final String name = unlinkTmpFile.getName();
  if (!name.endsWith(DatanodeUtil.UNLINK_BLOCK_SUFFIX)) {
    throw new IllegalArgumentException("unlinkTmpFile=" + unlinkTmpFile
        + " does not end with " + DatanodeUtil.UNLINK_BLOCK_SUFFIX);
  }
  final int n = name.length() - DatanodeUtil.UNLINK_BLOCK_SUFFIX.length(); 
  return new File(unlinkTmpFile.getParentFile(), name.substring(0, n));
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
/**
 * Copy the block and meta files for the given block to the given destination.
 * @return the new meta and block files.
 * @throws IOException
 */
static File[] copyBlockFiles(long blockId, long genStamp, File srcMeta,
    File srcFile, File destRoot, boolean calculateChecksum)
    throws IOException {
  final File destDir = DatanodeUtil.idToBlockDir(destRoot, blockId);
  final File dstFile = new File(destDir, srcFile.getName());
  final File dstMeta = FsDatasetUtil.getMetaFile(dstFile, genStamp);
  return copyBlockFiles(srcMeta, srcFile, dstMeta, dstFile, calculateChecksum);
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
private File[] copyReplicaWithNewBlockIdAndGS(
    ReplicaUnderRecovery replicaInfo, String bpid, long newBlkId, long newGS)
    throws IOException {
  String blockFileName = Block.BLOCK_FILE_PREFIX + newBlkId;
  FsVolumeReference v = volumes.getNextVolume(
      replicaInfo.getVolume().getStorageType(), replicaInfo.getNumBytes());
  final File tmpDir = ((FsVolumeImpl) v.getVolume())
      .getBlockPoolSlice(bpid).getTmpDir();
  final File destDir = DatanodeUtil.idToBlockDir(tmpDir, newBlkId);
  final File dstBlockFile = new File(destDir, blockFileName);
  final File dstMetaFile = FsDatasetUtil.getMetaFile(dstBlockFile, newGS);
  return copyBlockFiles(replicaInfo.getMetaFile(), replicaInfo.getBlockFile(),
      dstMetaFile, dstBlockFile, true);
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
File addBlock(Block b, File f) throws IOException {
  File blockDir = DatanodeUtil.idToBlockDir(finalizedDir, b.getBlockId());
  if (!blockDir.exists()) {
    if (!blockDir.mkdirs()) {
      throw new IOException("Failed to mkdirs " + blockDir);
    }
  }
  File blockFile = FsDatasetImpl.moveBlockFiles(b, f, blockDir);
  File metaFile = FsDatasetUtil.getMetaFile(blockFile, b.getGenerationStamp());
  dfsUsage.incDfsUsed(b.getNumBytes()+metaFile.length());
  return blockFile;
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
/**
 * Move a persisted replica from lazypersist directory to a subdirectory
 * under finalized.
 */
File activateSavedReplica(Block b, File metaFile, File blockFile)
    throws IOException {
  final File blockDir = DatanodeUtil.idToBlockDir(finalizedDir, b.getBlockId());
  final File targetBlockFile = new File(blockDir, blockFile.getName());
  final File targetMetaFile = new File(blockDir, metaFile.getName());
  FileUtils.moveFile(blockFile, targetBlockFile);
  FsDatasetImpl.LOG.info("Moved " + blockFile + " to " + targetBlockFile);
  FileUtils.moveFile(metaFile, targetMetaFile);
  FsDatasetImpl.LOG.info("Moved " + metaFile + " to " + targetMetaFile);
  return targetBlockFile;
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
public boolean changeGenStampOfBlock(int dnIndex, ExtendedBlock blk,
    long newGenStamp) throws IOException {
  File blockFile = getBlockFile(dnIndex, blk);
  File metaFile = FsDatasetUtil.findMetaFile(blockFile);
  return metaFile.renameTo(new File(DatanodeUtil.getMetaName(
      blockFile.getAbsolutePath(), newGenStamp)));
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
/**
 * Make sure at least one non-transient volume has a saved copy of the replica.
 * An infinite loop is used to ensure the async lazy persist tasks are completely
 * done before verification. Caller of ensureLazyPersistBlocksAreSaved expects
 * either a successful pass or timeout failure.
 */
protected final void ensureLazyPersistBlocksAreSaved(
    LocatedBlocks locatedBlocks) throws IOException, InterruptedException {
  final String bpid = cluster.getNamesystem().getBlockPoolId();
  List<? extends FsVolumeSpi> volumes =
    cluster.getDataNodes().get(0).getFSDataset().getVolumes();
  final Set<Long> persistedBlockIds = new HashSet<Long>();

  while (persistedBlockIds.size() < locatedBlocks.getLocatedBlocks().size()) {
    // Take 1 second sleep before each verification iteration
    Thread.sleep(1000);

    for (LocatedBlock lb : locatedBlocks.getLocatedBlocks()) {
      for (FsVolumeSpi v : volumes) {
        if (v.isTransientStorage()) {
          continue;
        }

        FsVolumeImpl volume = (FsVolumeImpl) v;
        File lazyPersistDir = volume.getBlockPoolSlice(bpid).getLazypersistDir();

        long blockId = lb.getBlock().getBlockId();
        File targetDir =
          DatanodeUtil.idToBlockDir(lazyPersistDir, blockId);
        File blockFile = new File(targetDir, lb.getBlock().getBlockName());
        if (blockFile.exists()) {
          // Found a persisted copy for this block and added to the Set
          persistedBlockIds.add(blockId);
        }
      }
    }
  }

  // We should have found a persisted copy for each located block.
  assertThat(persistedBlockIds.size(), is(locatedBlocks.getLocatedBlocks().size()));
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
/**
 * Copy the block and meta files for the given block to the given destination.
 * @return the new meta and block files.
 * @throws IOException
 */
static File[] copyBlockFiles(long blockId, long genStamp, File srcMeta,
    File srcFile, File destRoot, boolean calculateChecksum,
    int smallBufferSize, final Configuration conf) throws IOException {
  final File destDir = DatanodeUtil.idToBlockDir(destRoot, blockId);
  final File dstFile = new File(destDir, srcFile.getName());
  final File dstMeta = FsDatasetUtil.getMetaFile(dstFile, genStamp);
  return copyBlockFiles(srcMeta, srcFile, dstMeta, dstFile, calculateChecksum,
      smallBufferSize, conf);
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
private File[] copyReplicaWithNewBlockIdAndGS(
    ReplicaUnderRecovery replicaInfo, String bpid, long newBlkId, long newGS)
    throws IOException {
  String blockFileName = Block.BLOCK_FILE_PREFIX + newBlkId;
  FsVolumeImpl v = (FsVolumeImpl) replicaInfo.getVolume();
  final File tmpDir = v.getBlockPoolSlice(bpid).getTmpDir();
  final File destDir = DatanodeUtil.idToBlockDir(tmpDir, newBlkId);
  final File dstBlockFile = new File(destDir, blockFileName);
  final File dstMetaFile = FsDatasetUtil.getMetaFile(dstBlockFile, newGS);
  return copyBlockFiles(replicaInfo.getMetaFile(),
      replicaInfo.getBlockFile(),
      dstMetaFile, dstBlockFile, true, smallBufferSize, conf);
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
File addFinalizedBlock(Block b, File f) throws IOException {
  File blockDir = DatanodeUtil.idToBlockDir(finalizedDir, b.getBlockId());
  if (!blockDir.exists()) {
    if (!blockDir.mkdirs()) {
      throw new IOException("Failed to mkdirs " + blockDir);
    }
  }
  File blockFile = FsDatasetImpl.moveBlockFiles(b, f, blockDir);
  File metaFile = FsDatasetUtil.getMetaFile(blockFile, b.getGenerationStamp());
  dfsUsage.incDfsUsed(b.getNumBytes()+metaFile.length());
  return blockFile;
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
/**
 * Make sure at least one non-transient volume has a saved copy of the replica.
 * An infinite loop is used to ensure the async lazy persist tasks are completely
 * done before verification. Caller of ensureLazyPersistBlocksAreSaved expects
 * either a successful pass or timeout failure.
 */
protected final void ensureLazyPersistBlocksAreSaved(
    LocatedBlocks locatedBlocks) throws IOException, InterruptedException {
  final String bpid = cluster.getNamesystem().getBlockPoolId();

  final Set<Long> persistedBlockIds = new HashSet<Long>();

  try (FsDatasetSpi.FsVolumeReferences volumes =
      cluster.getDataNodes().get(0).getFSDataset().getFsVolumeReferences()) {
    while (persistedBlockIds.size() < locatedBlocks.getLocatedBlocks()
        .size()) {
      // Take 1 second sleep before each verification iteration
      Thread.sleep(1000);

      for (LocatedBlock lb : locatedBlocks.getLocatedBlocks()) {
        for (FsVolumeSpi v : volumes) {
          if (v.isTransientStorage()) {
            continue;
          }

          FsVolumeImpl volume = (FsVolumeImpl) v;
          File lazyPersistDir =
              volume.getBlockPoolSlice(bpid).getLazypersistDir();

          long blockId = lb.getBlock().getBlockId();
          File targetDir =
              DatanodeUtil.idToBlockDir(lazyPersistDir, blockId);
          File blockFile = new File(targetDir, lb.getBlock().getBlockName());
          if (blockFile.exists()) {
            // Found a persisted copy for this block and added to the Set
            persistedBlockIds.add(blockId);
          }
        }
      }
    }
  }

  // We should have found a persisted copy for each located block.
  assertThat(persistedBlockIds.size(), is(locatedBlocks.getLocatedBlocks().size()));
}
 

import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil; //导入依赖的package包/类
@Override
public void changeStoredGenerationStamp(
    ExtendedBlock block, long newGenStamp) throws IOException {
  File blockFile =
      dataset.getBlockFile(block.getBlockPoolId(), block.getBlockId());
  File metaFile = FsDatasetUtil.findMetaFile(blockFile);
  File newMetaFile = new File(
      DatanodeUtil.getMetaName(blockFile.getAbsolutePath(), newGenStamp));
  Files.move(metaFile.toPath(), newMetaFile.toPath(),
      StandardCopyOption.ATOMIC_MOVE);
}