コード例 #1
0
  public synchronized InputStream getBlockInputStream(Block b, long seekOffset) throws IOException {

    File blockFile = getBlockFile(b);
    RandomAccessFile blockInFile = new RandomAccessFile(blockFile, "r");
    if (seekOffset > 0) {
      blockInFile.seek(seekOffset);
    }
    return new FileInputStream(blockInFile.getFD());
  }
コード例 #2
0
  private static void truncateBlock(File blockFile, File metaFile, long oldlen, long newlen)
      throws IOException {
    if (newlen == oldlen) {
      return;
    }
    if (newlen > oldlen) {
      throw new IOException(
          "Cannout truncate block to from oldlen (=" + oldlen + ") to newlen (=" + newlen + ")");
    }

    DataChecksum dcs = BlockMetadataHeader.readHeader(metaFile).getChecksum();
    int checksumsize = dcs.getChecksumSize();
    int bpc = dcs.getBytesPerChecksum();
    long n = (newlen - 1) / bpc + 1;
    long newmetalen = BlockMetadataHeader.getHeaderSize() + n * checksumsize;
    long lastchunkoffset = (n - 1) * bpc;
    int lastchunksize = (int) (newlen - lastchunkoffset);
    byte[] b = new byte[Math.max(lastchunksize, checksumsize)];

    RandomAccessFile blockRAF = new RandomAccessFile(blockFile, "rw");
    try {
      // truncate blockFile
      blockRAF.setLength(newlen);

      // read last chunk
      blockRAF.seek(lastchunkoffset);
      blockRAF.readFully(b, 0, lastchunksize);
    } finally {
      blockRAF.close();
    }

    // compute checksum
    dcs.update(b, 0, lastchunksize);
    dcs.writeValue(b, 0, false);

    // update metaFile
    RandomAccessFile metaRAF = new RandomAccessFile(metaFile, "rw");
    try {
      metaRAF.setLength(newmetalen);
      metaRAF.seek(newmetalen - checksumsize);
      metaRAF.write(b, 0, checksumsize);
    } finally {
      metaRAF.close();
    }
  }
コード例 #3
0
  /** Returns handles to the block file and its metadata file */
  public synchronized BlockInputStreams getTmpInputStreams(Block b, long blkOffset, long ckoff)
      throws IOException {

    DatanodeBlockInfo info = volumeMap.get(b);
    if (info == null) {
      throw new IOException("Block " + b + " does not exist in volumeMap.");
    }
    FSVolume v = info.getVolume();
    File blockFile = v.getTmpFile(b);
    RandomAccessFile blockInFile = new RandomAccessFile(blockFile, "r");
    if (blkOffset > 0) {
      blockInFile.seek(blkOffset);
    }
    File metaFile = getMetaFile(blockFile, b);
    RandomAccessFile metaInFile = new RandomAccessFile(metaFile, "r");
    if (ckoff > 0) {
      metaInFile.seek(ckoff);
    }
    return new BlockInputStreams(
        new FileInputStream(blockInFile.getFD()), new FileInputStream(metaInFile.getFD()));
  }