import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * This should be primarily used for testing.
 * @return clone of replica store in datanode memory
 */
ReplicaInfo fetchReplicaInfo(String bpid, long blockId) {
  ReplicaInfo r = volumeMap.get(bpid, blockId);
  if(r == null)
    return null;
  switch(r.getState()) {
  case FINALIZED:
    return new FinalizedReplica((FinalizedReplica)r);
  case RBW:
    return new ReplicaBeingWritten((ReplicaBeingWritten)r);
  case RWR:
    return new ReplicaWaitingToBeRecovered((ReplicaWaitingToBeRecovered)r);
  case RUR:
    return new ReplicaUnderRecovery((ReplicaUnderRecovery)r);
  case TEMPORARY:
    return new ReplicaInPipeline((ReplicaInPipeline)r);
  }
  return null;
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Bump a replica's generation stamp to a new one.
 * Its on-disk meta file name is renamed to be the new one too.
 * 
 * @param replicaInfo a replica
 * @param newGS new generation stamp
 * @throws IOException if rename fails
 */
private void bumpReplicaGS(ReplicaInfo replicaInfo, 
    long newGS) throws IOException { 
  long oldGS = replicaInfo.getGenerationStamp();
  File oldmeta = replicaInfo.getMetaFile();
  replicaInfo.setGenerationStamp(newGS);
  File newmeta = replicaInfo.getMetaFile();

  // rename meta file to new GS
  if (LOG.isDebugEnabled()) {
    LOG.debug("Renaming " + oldmeta + " to " + newmeta);
  }
  try {
    NativeIO.renameTo(oldmeta, newmeta);
  } catch (IOException e) {
    replicaInfo.setGenerationStamp(oldGS); // restore old GS
    throw new IOException("Block " + replicaInfo + " reopen failed. " +
                          " Unable to move meta file  " + oldmeta +
                          " to " + newmeta, e);
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Remove the temporary block file (if any)
 */
@Override // FsDatasetSpi
public synchronized void unfinalizeBlock(ExtendedBlock b) throws IOException {
  ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), 
      b.getLocalBlock());
  if (replicaInfo != null && replicaInfo.getState() == ReplicaState.TEMPORARY) {
    // remove from volumeMap
    volumeMap.remove(b.getBlockPoolId(), b.getLocalBlock());
    
    // delete the on-disk temp file
    if (delBlockFromDisk(replicaInfo.getBlockFile(), 
        replicaInfo.getMetaFile(), b.getLocalBlock())) {
      LOG.warn("Block " + b + " unfinalized and removed. " );
    }
    if (replicaInfo.getVolume().isTransientStorage()) {
      ramDiskReplicaTracker.discardReplica(b.getBlockPoolId(), b.getBlockId(), true);
    }
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Check if a block is valid.
 *
 * @param b           The block to check.
 * @param minLength   The minimum length that the block must have.  May be 0.
 * @param state       If this is null, it is ignored.  If it is non-null, we
 *                        will check that the replica has this state.
 *
 * @throws ReplicaNotFoundException          If the replica is not found 
 *
 * @throws UnexpectedReplicaStateException   If the replica is not in the 
 *                                             expected state.
 * @throws FileNotFoundException             If the block file is not found or there
 *                                              was an error locating it.
 * @throws EOFException                      If the replica length is too short.
 * 
 * @throws IOException                       May be thrown from the methods called. 
 */
public void checkBlock(ExtendedBlock b, long minLength, ReplicaState state)
    throws ReplicaNotFoundException, UnexpectedReplicaStateException,
    FileNotFoundException, EOFException, IOException {
  final ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), 
      b.getLocalBlock());
  if (replicaInfo == null) {
    throw new ReplicaNotFoundException(b);
  }
  if (replicaInfo.getState() != state) {
    throw new UnexpectedReplicaStateException(b,state);
  }
  if (!replicaInfo.getBlockFile().exists()) {
    throw new FileNotFoundException(replicaInfo.getBlockFile().getPath());
  }
  long onDiskLength = getLength(b);
  if (onDiskLength < minLength) {
    throw new EOFException(b + "'s on-disk length " + onDiskLength
        + " is shorter than minLength " + minLength);
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/** Check the files of a replica. */
static void checkReplicaFiles(final ReplicaInfo r) throws IOException {
  //check replica's file
  final File f = r.getBlockFile();
  if (!f.exists()) {
    throw new FileNotFoundException("File " + f + " not found, r=" + r);
  }
  if (r.getBytesOnDisk() != f.length()) {
    throw new IOException("File length mismatched.  The length of "
        + f + " is " + f.length() + " but r=" + r);
  }

  //check replica's meta file
  final File metafile = FsDatasetUtil.getMetaFile(f, r.getGenerationStamp());
  if (!metafile.exists()) {
    throw new IOException("Metafile " + metafile + " does not exist, r=" + r);
  }
  if (metafile.length() == 0) {
    throw new IOException("Metafile " + metafile + " is empty, r=" + r);
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Invalidate a block but does not delete the actual on-disk block file.
 *
 * It should only be used when deactivating disks.
 *
 * @param bpid the block pool ID.
 * @param block The block to be invalidated.
 */
public void invalidate(String bpid, ReplicaInfo block) {
  // If a DFSClient has the replica in its cache of short-circuit file
  // descriptors (and the client is using ShortCircuitShm), invalidate it.
  // The short-circuit registry is null in the unit tests, because the
  // datanode is mock object.
  if (datanode.getShortCircuitRegistry() != null) {
    datanode.getShortCircuitRegistry().processBlockInvalidation(
        new ExtendedBlockId(block.getBlockId(), bpid));

    // If the block is cached, start uncaching it.
    cacheManager.uncacheBlock(bpid, block.getBlockId());
  }

  datanode.notifyNamenodeDeletedBlock(new ExtendedBlock(bpid, block),
      block.getStorageUuid());
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Remove the replica's meta information from the map that matches
 * the input block's id and generation stamp
 * @param bpid block pool id
 * @param block block with its id as the key
 * @return the removed replica's meta information
 * @throws IllegalArgumentException if the input block is null
 */
ReplicaInfo remove(String bpid, Block block) {
  checkBlockPool(bpid);
  checkBlock(block);
  synchronized(mutex) {
    Map<Long, ReplicaInfo> m = map.get(bpid);
    if (m != null) {
      Long key = Long.valueOf(block.getBlockId());
      ReplicaInfo replicaInfo = m.get(key);
      if (replicaInfo != null &&
          block.getGenerationStamp() == replicaInfo.getGenerationStamp()) {
        return m.remove(key);
      } 
    }
  }
  
  return null;
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //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.ReplicaInfo; //导入依赖的package包/类
/**
 * Remove the temporary block file (if any)
 */
@Override // FsDatasetSpi
public synchronized void unfinalizeBlock(ExtendedBlock b) throws IOException {
  ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), 
      b.getLocalBlock());
  if (replicaInfo != null && replicaInfo.getState() == ReplicaState.TEMPORARY) {
    // remove from volumeMap
    volumeMap.remove(b.getBlockPoolId(), b.getLocalBlock());

    // delete the on-disk temp file
    if (delBlockFromDisk(replicaInfo.getBlockFile(), 
        replicaInfo.getMetaFile(), b.getLocalBlock())) {
      LOG.warn("Block " + b + " unfinalized and removed. " );
    }
    if (replicaInfo.getVolume().isTransientStorage()) {
      ramDiskReplicaTracker.discardReplica(b.getBlockPoolId(), b.getBlockId(), true);
    }
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Remove the replica's meta information from the map that matches
 * the input block's id and generation stamp
 * @param bpid block pool id
 * @param block block with its id as the key
 * @return the removed replica's meta information
 * @throws IllegalArgumentException if the input block is null
 */
ReplicaInfo remove(String bpid, Block block) {
  checkBlockPool(bpid);
  checkBlock(block);
  synchronized(mutex) {
    LightWeightResizableGSet<Block, ReplicaInfo> m = map.get(bpid);
    if (m != null) {
      ReplicaInfo replicaInfo = m.get(block);
      if (replicaInfo != null &&
          block.getGenerationStamp() == replicaInfo.getGenerationStamp()) {
        return m.remove(block);
      }
    }
  }
  
  return null;
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Remove the temporary block file (if any)
 */
@Override // FsDatasetSpi
public synchronized void unfinalizeBlock(ExtendedBlock b) throws IOException {
  ReplicaInfo replicaInfo =
      volumeMap.get(b.getBlockPoolId(), b.getLocalBlock());
  if (replicaInfo != null &&
      replicaInfo.getState() == ReplicaState.TEMPORARY) {
    // remove from volumeMap
    volumeMap.remove(b.getBlockPoolId(), b.getLocalBlock());
    
    // delete the on-disk temp file
    if (delBlockFromDisk(replicaInfo.getBlockFile(),
        replicaInfo.getMetaFile(), b.getLocalBlock())) {
      LOG.warn("Block " + b + " unfinalized and removed. ");
    }
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
@Override // FsDatasetSpi
public synchronized ReplicaInPipeline createRbw(ExtendedBlock b)
    throws IOException {
  ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), b.getBlockId());
  if (replicaInfo != null) {
    throw new ReplicaAlreadyExistsException("Block " + b +
        " already exists in state " + replicaInfo.getState() +
        " and thus cannot be created.");
  }
  // create a new block
  FsVolumeImpl v = volumes.getNextVolume(b.getNumBytes());
  // create a rbw file to hold block in the designated volume
  File f = v.createRbwFile(b.getBlockPoolId(), b.getLocalBlock());
  ReplicaBeingWritten newReplicaInfo =
      new ReplicaBeingWritten(b.getBlockId(), b.getGenerationStamp(), v,
          f.getParentFile());
  volumeMap.add(b.getBlockPoolId(), newReplicaInfo);
  return newReplicaInfo;
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Returns handles to the block file and its metadata file
 */
@Override // FsDatasetSpi
public synchronized ReplicaInputStreams getTmpInputStreams(ExtendedBlock b, 
                        long blkOffset, long ckoff) throws IOException {
  ReplicaInfo info = getReplicaInfo(b);
  FsVolumeReference ref = info.getVolume().obtainReference();
  try {
    File blockFile = info.getBlockFile();
    RandomAccessFile blockInFile = new RandomAccessFile(blockFile, "r");
    if (blkOffset > 0) {
      blockInFile.seek(blkOffset);
    }
    File metaFile = info.getMetaFile();
    RandomAccessFile metaInFile = new RandomAccessFile(metaFile, "r");
    if (ckoff > 0) {
      metaInFile.seek(ckoff);
    }
    return new ReplicaInputStreams(
        blockInFile.getFD(), metaInFile.getFD(), ref);
  } catch (IOException e) {
    IOUtils.cleanup(null, ref);
    throw e;
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
@Override // FsDatasetSpi
public synchronized ReplicaInPipeline createTemporary(StorageType storageType,
    ExtendedBlock b) throws IOException {
  ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), b.getBlockId());
  if (replicaInfo != null) {
    if (replicaInfo.getGenerationStamp() < b.getGenerationStamp()
        && replicaInfo instanceof ReplicaInPipeline) {
      // Stop the previous writer
      ((ReplicaInPipeline)replicaInfo)
                    .stopWriter(datanode.getDnConf().getXceiverStopTimeout());
      invalidate(b.getBlockPoolId(), new Block[]{replicaInfo});
    } else {
      throw new ReplicaAlreadyExistsException("Block " + b +
          " already exists in state " + replicaInfo.getState() +
          " and thus cannot be created.");
    }
  }
  
  FsVolumeImpl v = volumes.getNextVolume(storageType, b.getNumBytes());
  // create a temporary file to hold block in the designated volume
  File f = v.createTmpFile(b.getBlockPoolId(), b.getLocalBlock());
  ReplicaInPipeline newReplicaInfo = new ReplicaInPipeline(b.getBlockId(), 
      b.getGenerationStamp(), v, f.getParentFile(), 0);
  volumeMap.add(b.getBlockPoolId(), newReplicaInfo);
  return newReplicaInfo;
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Returns a clone of a replica stored in data-node memory.
 * Should be primarily used for testing.
 * @param blockId
 * @return
 */
ReplicaInfo fetchReplicaInfo(String bpid, long blockId) {
  ReplicaInfo r = volumeMap.get(bpid, blockId);
  if(r == null)
    return null;
  switch(r.getState()) {
  case FINALIZED:
    return new FinalizedReplica((FinalizedReplica)r);
  case RBW:
    return new ReplicaBeingWritten((ReplicaBeingWritten)r);
  case RWR:
    return new ReplicaWaitingToBeRecovered((ReplicaWaitingToBeRecovered)r);
  case RUR:
    return new ReplicaUnderRecovery((ReplicaUnderRecovery)r);
  case TEMPORARY:
    return new ReplicaInPipeline((ReplicaInPipeline)r);
  }
  return null;
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Returns handles to the block file and its metadata file
 */
@Override // FsDatasetSpi
public synchronized ReplicaInputStreams getTmpInputStreams(ExtendedBlock b, 
                        long blkOffset, long ckoff) throws IOException {
  ReplicaInfo info = getReplicaInfo(b);
  File blockFile = info.getBlockFile();
  RandomAccessFile blockInFile = new RandomAccessFile(blockFile, "r");
  if (blkOffset > 0) {
    blockInFile.seek(blkOffset);
  }
  File metaFile = info.getMetaFile();
  RandomAccessFile metaInFile = new RandomAccessFile(metaFile, "r");
  if (ckoff > 0) {
    metaInFile.seek(ckoff);
  }
  return new ReplicaInputStreams(blockInFile.getFD(), metaInFile.getFD());
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
@Override // FsDatasetSpi
public synchronized ReplicaInPipeline createRbw(ExtendedBlock b)
    throws IOException {
  ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), 
      b.getBlockId());
  if (replicaInfo != null) {
    throw new ReplicaAlreadyExistsException("Block " + b +
    " already exists in state " + replicaInfo.getState() +
    " and thus cannot be created.");
  }
  // create a new block
  FsVolumeImpl v = volumes.getNextVolume(b.getNumBytes());
  // create a rbw file to hold block in the designated volume
  File f = v.createRbwFile(b.getBlockPoolId(), b.getLocalBlock());
  ReplicaBeingWritten newReplicaInfo = new ReplicaBeingWritten(b.getBlockId(), 
      b.getGenerationStamp(), v, f.getParentFile());
  volumeMap.add(b.getBlockPoolId(), newReplicaInfo);
  return newReplicaInfo;
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
@Override // FsDatasetSpi
public synchronized ReplicaInPipeline createTemporary(ExtendedBlock b)
    throws IOException {
  ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), b.getBlockId());
  if (replicaInfo != null) {
    throw new ReplicaAlreadyExistsException("Block " + b +
        " already exists in state " + replicaInfo.getState() +
        " and thus cannot be created.");
  }
  
  FsVolumeImpl v = volumes.getNextVolume(b.getNumBytes());
  // create a temporary file to hold block in the designated volume
  File f = v.createTmpFile(b.getBlockPoolId(), b.getLocalBlock());
  ReplicaInPipeline newReplicaInfo = new ReplicaInPipeline(b.getBlockId(), 
      b.getGenerationStamp(), v, f.getParentFile());
  volumeMap.add(b.getBlockPoolId(), newReplicaInfo);
  
  return newReplicaInfo;
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //导入依赖的package包/类
/**
 * Remove the temporary block file (if any)
 */
@Override // FsDatasetSpi
public synchronized void unfinalizeBlock(ExtendedBlock b) throws IOException {
  ReplicaInfo replicaInfo = volumeMap.get(b.getBlockPoolId(), 
      b.getLocalBlock());
  if (replicaInfo != null && replicaInfo.getState() == ReplicaState.TEMPORARY) {
    // remove from volumeMap
    volumeMap.remove(b.getBlockPoolId(), b.getLocalBlock());
    
    // delete the on-disk temp file
    if (delBlockFromDisk(replicaInfo.getBlockFile(), 
        replicaInfo.getMetaFile(), b.getLocalBlock())) {
      LOG.warn("Block " + b + " unfinalized and removed. " );
    }
  }
}
 

import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo; //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();
    }
  }
}