private void copyBlock(DFSClient dfs, LocatedBlock lblock,
OutputStream fos) throws Exception {
int failures = 0;
InetSocketAddress targetAddr = null;
TreeSet<DatanodeInfo> deadNodes = new TreeSet<DatanodeInfo>();
BlockReader blockReader = null;
ExtendedBlock block = lblock.getBlock();
while (blockReader == null) {
DatanodeInfo chosenNode;
try {
chosenNode = bestNode(dfs, lblock.getLocations(), deadNodes);
targetAddr = NetUtils.createSocketAddr(chosenNode.getXferAddr());
} catch (IOException ie) {
if (failures >= DFSConfigKeys.DFS_CLIENT_MAX_BLOCK_ACQUIRE_FAILURES_DEFAULT) {
throw new IOException("Could not obtain block " + lblock, ie);
}
LOG.info("Could not obtain block from any node: " + ie);
try {
Thread.sleep(10000);
} catch (InterruptedException iex) {
}
deadNodes.clear();
failures++;
continue;
}
try {
String file = BlockReaderFactory.getFileName(targetAddr,
block.getBlockPoolId(), block.getBlockId());
blockReader = new BlockReaderFactory(dfs.getConf()).
setFileName(file).
setBlock(block).
setBlockToken(lblock.getBlockToken()).
setStartOffset(0).
setLength(-1).
setVerifyChecksum(true).
setClientName("fsck").
setDatanodeInfo(chosenNode).
setInetSocketAddress(targetAddr).
setCachingStrategy(CachingStrategy.newDropBehind()).
setClientCacheContext(dfs.getClientContext()).
setConfiguration(namenode.conf).
setRemotePeerFactory(new RemotePeerFactory() {
@Override
public Peer newConnectedPeer(InetSocketAddress addr)
throws IOException {
Peer peer = null;
Socket s = NetUtils.getDefaultSocketFactory(conf).createSocket();
try {
s.connect(addr, HdfsServerConstants.READ_TIMEOUT);
s.setSoTimeout(HdfsServerConstants.READ_TIMEOUT);
peer = TcpPeerServer.peerFromSocketAndKey(s, namenode.getRpcServer().
getDataEncryptionKey());
} finally {
if (peer == null) {
IOUtils.closeQuietly(s);
}
}
return peer;
}
}).
build();
} catch (IOException ex) {
// Put chosen node into dead list, continue
LOG.info("Failed to connect to " + targetAddr + ":" + ex);
deadNodes.add(chosenNode);
}
}
byte[] buf = new byte[1024];
int cnt = 0;
boolean success = true;
long bytesRead = 0;
try {
while ((cnt = blockReader.read(buf, 0, buf.length)) > 0) {
fos.write(buf, 0, cnt);
bytesRead += cnt;
}
if ( bytesRead != block.getNumBytes() ) {
throw new IOException("Recorded block size is " + block.getNumBytes() +
", but datanode returned " +bytesRead+" bytes");
}
} catch (Exception e) {
LOG.error("Error reading block", e);
success = false;
} finally {
blockReader.close();
}
if (!success) {
throw new Exception("Could not copy block data for " + lblock.getBlock());
}
}