* as an UNKNOWN value.
*/
long expected = PipelineAck.UNKOWN_SEQNO;
long seqno = PipelineAck.UNKOWN_SEQNO;;
PipelineAck ack = new PipelineAck();
boolean localMirrorError = mirrorError;
try {
Packet pkt = null;
synchronized (this) {
// wait for a packet to arrive
while (running && datanode.shouldRun && ackQueue.size() == 0) {
if (LOG.isDebugEnabled()) {
LOG.debug("PacketResponder " + numTargets +
" seqno = " + seqno +
" for block " + block +
" waiting for local datanode to finish write.");
}
wait();
}
if (!running || !datanode.shouldRun) {
break;
}
pkt = ackQueue.removeFirst();
expected = pkt.seqno;
notifyAll();
}
// receive an ack if DN is not the last one in the pipeline
if (numTargets > 0 && !localMirrorError) {
// read an ack from downstream datanode
ack.readFields(mirrorIn);
if (LOG.isDebugEnabled()) {
LOG.debug("PacketResponder " + numTargets +
" for block " + block + " got " + ack);
}
seqno = ack.getSeqno();
// verify seqno
if (seqno != expected) {
throw new IOException("PacketResponder " + numTargets +
" for block " + block +
" expected seqno:" + expected +
" received:" + seqno);
}
}
lastPacketInBlock = pkt.lastPacketInBlock;
} catch (InterruptedException ine) {
isInterrupted = true;
} catch (IOException ioe) {
if (Thread.interrupted()) {
isInterrupted = true;
} else {
// continue to run even if can not read from mirror
// notify client of the error
// and wait for the client to shut down the pipeline
mirrorError = true;
LOG.info("PacketResponder " + block + " " + numTargets +
" Exception " + StringUtils.stringifyException(ioe));
}
}
if (Thread.interrupted() || isInterrupted) {
/* The receiver thread cancelled this thread.
* We could also check any other status updates from the
* receiver thread (e.g. if it is ok to write to replyOut).
* It is prudent to not send any more status back to the client
* because this datanode has a problem. The upstream datanode
* will detect that this datanode is bad, and rightly so.
*/
LOG.info("PacketResponder " + block + " " + numTargets +
" : Thread is interrupted.");
break;
}
// If this is the last packet in block, then close block
// file and finalize the block before responding success
if (lastPacketInBlock && !receiver.finalized) {
receiver.close();
final long endTime = ClientTraceLog.isInfoEnabled() ? System.nanoTime() : 0;
block.setNumBytes(receiver.offsetInBlock);
datanode.data.finalizeBlock(block);
datanode.myMetrics.incrBlocksWritten();
datanode.notifyNamenodeReceivedBlock(block,
DataNode.EMPTY_DEL_HINT);
if (ClientTraceLog.isInfoEnabled() &&
receiver.clientName.length() > 0) {
long offset = 0;
ClientTraceLog.info(String.format(DN_CLIENTTRACE_FORMAT,
receiver.inAddr, receiver.myAddr, block.getNumBytes(),
"HDFS_WRITE", receiver.clientName, offset,
datanode.dnRegistration.getStorageID(), block, endTime-startTime));
} else {
LOG.info("Received block " + block +
" of size " + block.getNumBytes() +
" from " + receiver.inAddr);
}
}
// construct my ack message
short[] replies = null;
if (mirrorError) { // no ack is read
replies = new short[2];
replies[0] = DataTransferProtocol.OP_STATUS_SUCCESS;
replies[1] = DataTransferProtocol.OP_STATUS_ERROR;
} else {
short ackLen = numTargets == 0 ? 0 : ack.getNumOfReplies();
replies = new short[1+ackLen];
replies[0] = DataTransferProtocol.OP_STATUS_SUCCESS;
for (int i=0; i<ackLen; i++) {
replies[i+1] = ack.getReply(i);
}
}
PipelineAck replyAck = new PipelineAck(expected, replies);
// send my ack back to upstream datanode
replyAck.write(replyOut);
replyOut.flush();
if (LOG.isDebugEnabled()) {
LOG.debug("PacketResponder " + numTargets +
" for block " + block +
" responded an ack: " + replyAck);