/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hdfs.server.datanode;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketException;
import org.apache.commons.logging.Log;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.DataTransferProtocol;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.FSConstants;
import org.apache.hadoop.hdfs.server.common.HdfsConstants;
import org.apache.hadoop.hdfs.server.datanode.FSDatasetInterface.MetaDataInputStream;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.MD5Hash;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.util.DataChecksum;
import org.apache.hadoop.util.StringUtils;
import static org.apache.hadoop.hdfs.server.datanode.DataNode.DN_CLIENTTRACE_FORMAT;
/**
* Thread for processing incoming/outgoing data stream.
*/
class DataXceiver implements Runnable, FSConstants {
public static final Log LOG = DataNode.LOG;
static final Log ClientTraceLog = DataNode.ClientTraceLog;
Socket s;
final String remoteAddress; // address of remote side
final String localAddress; // local address of this daemon
DataNode datanode;
DataXceiverServer dataXceiverServer;
public DataXceiver(Socket s, DataNode datanode,
DataXceiverServer dataXceiverServer) {
this.s = s;
this.datanode = datanode;
this.dataXceiverServer = dataXceiverServer;
dataXceiverServer.childSockets.put(s, s);
remoteAddress = s.getRemoteSocketAddress().toString();
localAddress = s.getLocalSocketAddress().toString();
LOG.debug("Number of active connections is: " + datanode.getXceiverCount());
}
/**
* Read/write data from/to the DataXceiveServer.
*/
public void run() {
DataInputStream in=null;
try {
in = new DataInputStream(
new BufferedInputStream(NetUtils.getInputStream(s),
SMALL_BUFFER_SIZE));
short version = in.readShort();
if ( version != DataTransferProtocol.DATA_TRANSFER_VERSION ) {
throw new IOException( "Version Mismatch" );
}
boolean local = s.getInetAddress().equals(s.getLocalAddress());
byte op = in.readByte();
// Make sure the xciver count is not exceeded
int curXceiverCount = datanode.getXceiverCount();
if (curXceiverCount > dataXceiverServer.maxXceiverCount) {
throw new IOException("xceiverCount " + curXceiverCount
+ " exceeds the limit of concurrent xcievers "
+ dataXceiverServer.maxXceiverCount);
}
long startTime = DataNode.now();
switch ( op ) {
case DataTransferProtocol.OP_READ_BLOCK:
readBlock( in );
datanode.myMetrics.readBlockOp.inc(DataNode.now() - startTime);
if (local)
datanode.myMetrics.readsFromLocalClient.inc();
else
datanode.myMetrics.readsFromRemoteClient.inc();
break;
case DataTransferProtocol.OP_WRITE_BLOCK:
writeBlock( in );
datanode.myMetrics.writeBlockOp.inc(DataNode.now() - startTime);
if (local)
datanode.myMetrics.writesFromLocalClient.inc();
else
datanode.myMetrics.writesFromRemoteClient.inc();
break;
case DataTransferProtocol.OP_READ_METADATA:
readMetadata( in );
datanode.myMetrics.readMetadataOp.inc(DataNode.now() - startTime);
break;
case DataTransferProtocol.OP_REPLACE_BLOCK: // for balancing purpose; send to a destination
replaceBlock(in);
datanode.myMetrics.replaceBlockOp.inc(DataNode.now() - startTime);
break;
case DataTransferProtocol.OP_COPY_BLOCK:
// for balancing purpose; send to a proxy source
copyBlock(in);
datanode.myMetrics.copyBlockOp.inc(DataNode.now() - startTime);
break;
case DataTransferProtocol.OP_BLOCK_CHECKSUM: //get the checksum of a block
getBlockChecksum(in);
datanode.myMetrics.blockChecksumOp.inc(DataNode.now() - startTime);
break;
default:
throw new IOException("Unknown opcode " + op + " in data stream");
}
} catch (Throwable t) {
LOG.error(datanode.dnRegistration + ":DataXceiver",t);
} finally {
LOG.debug(datanode.dnRegistration + ":Number of active connections is: "
+ datanode.getXceiverCount());
IOUtils.closeStream(in);
IOUtils.closeSocket(s);
dataXceiverServer.childSockets.remove(s);
}
}
/**
* Read a block from the disk.
* @param in The stream to read from
* @throws IOException
*/
private void readBlock(DataInputStream in) throws IOException {
//
// Read in the header
//
long blockId = in.readLong();
Block block = new Block( blockId, 0 , in.readLong());
long startOffset = in.readLong();
long length = in.readLong();
String clientName = Text.readString(in);
// send the block
OutputStream baseStream = NetUtils.getOutputStream(s,
datanode.socketWriteTimeout);
DataOutputStream out = new DataOutputStream(
new BufferedOutputStream(baseStream, SMALL_BUFFER_SIZE));
BlockSender blockSender = null;
final String clientTraceFmt =
clientName.length() > 0 && ClientTraceLog.isInfoEnabled()
? String.format(DN_CLIENTTRACE_FORMAT, localAddress, remoteAddress,
"%d", "HDFS_READ", clientName,
datanode.dnRegistration.getStorageID(), block)
: datanode.dnRegistration + " Served block " + block + " to " +
s.getInetAddress();
try {
try {
blockSender = new BlockSender(block, startOffset, length,
true, true, false, datanode, clientTraceFmt);
} catch(IOException e) {
out.writeShort(DataTransferProtocol.OP_STATUS_ERROR);
throw e;
}
out.writeShort(DataTransferProtocol.OP_STATUS_SUCCESS); // send op status
long read = blockSender.sendBlock(out, baseStream, null); // send data
if (blockSender.isBlockReadFully()) {
// See if client verification succeeded.
// This is an optional response from client.
try {
if (in.readShort() == DataTransferProtocol.OP_STATUS_CHECKSUM_OK &&
datanode.blockScanner != null) {
datanode.blockScanner.verifiedByClient(block);
}
} catch (IOException ignored) {}
}
datanode.myMetrics.bytesRead.inc((int) read);
datanode.myMetrics.blocksRead.inc();
} catch ( SocketException ignored ) {
// Its ok for remote side to close the connection anytime.
datanode.myMetrics.blocksRead.inc();
} catch ( IOException ioe ) {
/* What exactly should we do here?
* Earlier version shutdown() datanode if there is disk error.
*/
LOG.warn(datanode.dnRegistration + ":Got exception while serving " +
block + " to " +
s.getInetAddress() + ":\n" +
StringUtils.stringifyException(ioe) );
throw ioe;
} finally {
IOUtils.closeStream(out);
IOUtils.closeStream(blockSender);
}
}
/**
* Write a block to disk.
*
* @param in The stream to read from
* @throws IOException
*/
private void writeBlock(DataInputStream in) throws IOException {
DatanodeInfo srcDataNode = null;
LOG.debug("writeBlock receive buf size " + s.getReceiveBufferSize() +
" tcp no delay " + s.getTcpNoDelay());
//
// Read in the header
//
Block block = new Block(in.readLong(),
dataXceiverServer.estimateBlockSize, in.readLong());
LOG.info("Receiving block " + block +
" src: " + remoteAddress +
" dest: " + localAddress);
int pipelineSize = in.readInt(); // num of datanodes in entire pipeline
boolean isRecovery = in.readBoolean(); // is this part of recovery?
String client = Text.readString(in); // working on behalf of this client
boolean hasSrcDataNode = in.readBoolean(); // is src node info present
if (hasSrcDataNode) {
srcDataNode = new DatanodeInfo();
srcDataNode.readFields(in);
}
int numTargets = in.readInt();
if (numTargets < 0) {
throw new IOException("Mislabelled incoming datastream.");
}
DatanodeInfo targets[] = new DatanodeInfo[numTargets];
for (int i = 0; i < targets.length; i++) {
DatanodeInfo tmp = new DatanodeInfo();
tmp.readFields(in);
targets[i] = tmp;
}
DataOutputStream mirrorOut = null; // stream to next target
DataInputStream mirrorIn = null; // reply from next target
DataOutputStream replyOut = null; // stream to prev target
Socket mirrorSock = null; // socket to next target
BlockReceiver blockReceiver = null; // responsible for data handling
String mirrorNode = null; // the name:port of next target
String firstBadLink = ""; // first datanode that failed in connection setup
try {
// open a block receiver and check if the block does not exist
blockReceiver = new BlockReceiver(block, in,
s.getRemoteSocketAddress().toString(),
s.getLocalSocketAddress().toString(),
isRecovery, client, srcDataNode, datanode);
// get a connection back to the previous target
replyOut = new DataOutputStream(
NetUtils.getOutputStream(s, datanode.socketWriteTimeout));
//
// Open network conn to backup machine, if
// appropriate
//
if (targets.length > 0) {
InetSocketAddress mirrorTarget = null;
// Connect to backup machine
mirrorNode = targets[0].getName();
mirrorTarget = NetUtils.createSocketAddr(mirrorNode);
mirrorSock = datanode.newSocket();
try {
int timeoutValue = numTargets * datanode.socketTimeout;
int writeTimeout = datanode.socketWriteTimeout +
(HdfsConstants.WRITE_TIMEOUT_EXTENSION * numTargets);
NetUtils.connect(mirrorSock, mirrorTarget, timeoutValue);
mirrorSock.setSoTimeout(timeoutValue);
mirrorSock.setSendBufferSize(DEFAULT_DATA_SOCKET_SIZE);
mirrorOut = new DataOutputStream(
new BufferedOutputStream(
NetUtils.getOutputStream(mirrorSock, writeTimeout),
SMALL_BUFFER_SIZE));
mirrorIn = new DataInputStream(NetUtils.getInputStream(mirrorSock));
// Write header: Copied from DFSClient.java!
mirrorOut.writeShort( DataTransferProtocol.DATA_TRANSFER_VERSION );
mirrorOut.write( DataTransferProtocol.OP_WRITE_BLOCK );
mirrorOut.writeLong( block.getBlockId() );
mirrorOut.writeLong( block.getGenerationStamp() );
mirrorOut.writeInt( pipelineSize );
mirrorOut.writeBoolean( isRecovery );
Text.writeString( mirrorOut, client );
mirrorOut.writeBoolean(hasSrcDataNode);
if (hasSrcDataNode) { // pass src node information
srcDataNode.write(mirrorOut);
}
mirrorOut.writeInt( targets.length - 1 );
for ( int i = 1; i < targets.length; i++ ) {
targets[i].write( mirrorOut );
}
blockReceiver.writeChecksumHeader(mirrorOut);
mirrorOut.flush();
// read connect ack (only for clients, not for replication req)
if (client.length() != 0) {
firstBadLink = Text.readString(mirrorIn);
if (LOG.isDebugEnabled() || firstBadLink.length() > 0) {
LOG.info("Datanode " + targets.length +
" got response for connect ack " +
" from downstream datanode with firstbadlink as " +
firstBadLink);
}
}
} catch (IOException e) {
if (client.length() != 0) {
Text.writeString(replyOut, mirrorNode);
replyOut.flush();
}
IOUtils.closeStream(mirrorOut);
mirrorOut = null;
IOUtils.closeStream(mirrorIn);
mirrorIn = null;
IOUtils.closeSocket(mirrorSock);
mirrorSock = null;
if (client.length() > 0) {
throw e;
} else {
LOG.info(datanode.dnRegistration + ":Exception transfering block " +
block + " to mirror " + mirrorNode +
". continuing without the mirror.\n" +
StringUtils.stringifyException(e));
}
}
}
// send connect ack back to source (only for clients)
if (client.length() != 0) {
if (LOG.isDebugEnabled() || firstBadLink.length() > 0) {
LOG.info("Datanode " + targets.length +
" forwarding connect ack to upstream firstbadlink is " +
firstBadLink);
}
Text.writeString(replyOut, firstBadLink);
replyOut.flush();
}
// receive the block and mirror to the next target
String mirrorAddr = (mirrorSock == null) ? null : mirrorNode;
blockReceiver.receiveBlock(mirrorOut, mirrorIn, replyOut,
mirrorAddr, null, targets.length);
// if this write is for a replication request (and not
// from a client), then confirm block. For client-writes,
// the block is finalized in the PacketResponder.
if (client.length() == 0) {
datanode.notifyNamenodeReceivedBlock(block, DataNode.EMPTY_DEL_HINT);
LOG.info("Received block " + block +
" src: " + remoteAddress +
" dest: " + localAddress +
" of size " + block.getNumBytes());
}
if (datanode.blockScanner != null) {
datanode.blockScanner.addBlock(block);
}
} catch (IOException ioe) {
LOG.info("writeBlock " + block + " received exception " + ioe);
throw ioe;
} finally {
// close all opened streams
IOUtils.closeStream(mirrorOut);
IOUtils.closeStream(mirrorIn);
IOUtils.closeStream(replyOut);
IOUtils.closeSocket(mirrorSock);
IOUtils.closeStream(blockReceiver);
}
}
/**
* Reads the metadata and sends the data in one 'DATA_CHUNK'.
* @param in
*/
void readMetadata(DataInputStream in) throws IOException {
Block block = new Block( in.readLong(), 0 , in.readLong());
MetaDataInputStream checksumIn = null;
DataOutputStream out = null;
try {
checksumIn = datanode.data.getMetaDataInputStream(block);
long fileSize = checksumIn.getLength();
if (fileSize >= 1L<<31 || fileSize <= 0) {
throw new IOException("Unexpected size for checksumFile of block" +
block);
}
byte [] buf = new byte[(int)fileSize];
IOUtils.readFully(checksumIn, buf, 0, buf.length);
out = new DataOutputStream(
NetUtils.getOutputStream(s, datanode.socketWriteTimeout));
out.writeByte(DataTransferProtocol.OP_STATUS_SUCCESS);
out.writeInt(buf.length);
out.write(buf);
//last DATA_CHUNK
out.writeInt(0);
} finally {
IOUtils.closeStream(out);
IOUtils.closeStream(checksumIn);
}
}
/**
* Get block checksum (MD5 of CRC32).
* @param in
*/
void getBlockChecksum(DataInputStream in) throws IOException {
final Block block = new Block(in.readLong(), 0 , in.readLong());
DataOutputStream out = null;
final MetaDataInputStream metadataIn = datanode.data.getMetaDataInputStream(block);
final DataInputStream checksumIn = new DataInputStream(new BufferedInputStream(
metadataIn, BUFFER_SIZE));
try {
//read metadata file
final BlockMetadataHeader header = BlockMetadataHeader.readHeader(checksumIn);
final DataChecksum checksum = header.getChecksum();
final int bytesPerCRC = checksum.getBytesPerChecksum();
final long crcPerBlock = (metadataIn.getLength()
- BlockMetadataHeader.getHeaderSize())/checksum.getChecksumSize();
//compute block checksum
final MD5Hash md5 = MD5Hash.digest(checksumIn);
if (LOG.isDebugEnabled()) {
LOG.debug("block=" + block + ", bytesPerCRC=" + bytesPerCRC
+ ", crcPerBlock=" + crcPerBlock + ", md5=" + md5);
}
//write reply
out = new DataOutputStream(
NetUtils.getOutputStream(s, datanode.socketWriteTimeout));
out.writeShort(DataTransferProtocol.OP_STATUS_SUCCESS);
out.writeInt(bytesPerCRC);
out.writeLong(crcPerBlock);
md5.write(out);
out.flush();
} finally {
IOUtils.closeStream(out);
IOUtils.closeStream(checksumIn);
IOUtils.closeStream(metadataIn);
}
}
/**
* Read a block from the disk and then sends it to a destination.
*
* @param in The stream to read from
* @throws IOException
*/
private void copyBlock(DataInputStream in) throws IOException {
// Read in the header
long blockId = in.readLong(); // read block id
Block block = new Block(blockId, 0, in.readLong());
if (!dataXceiverServer.balanceThrottler.acquire()) { // not able to start
LOG.info("Not able to copy block " + blockId + " to "
+ s.getRemoteSocketAddress() + " because threads quota is exceeded.");
return;
}
BlockSender blockSender = null;
DataOutputStream reply = null;
boolean isOpSuccess = true;
try {
// check if the block exists or not
blockSender = new BlockSender(block, 0, -1, false, false, false,
datanode);
// set up response stream
OutputStream baseStream = NetUtils.getOutputStream(
s, datanode.socketWriteTimeout);
reply = new DataOutputStream(new BufferedOutputStream(
baseStream, SMALL_BUFFER_SIZE));
// send block content to the target
long read = blockSender.sendBlock(reply, baseStream,
dataXceiverServer.balanceThrottler);
datanode.myMetrics.bytesRead.inc((int) read);
datanode.myMetrics.blocksRead.inc();
LOG.info("Copied block " + block + " to " + s.getRemoteSocketAddress());
} catch (IOException ioe) {
isOpSuccess = false;
throw ioe;
} finally {
dataXceiverServer.balanceThrottler.release();
if (isOpSuccess) {
try {
// send one last byte to indicate that the resource is cleaned.
reply.writeChar('d');
} catch (IOException ignored) {
}
}
IOUtils.closeStream(reply);
IOUtils.closeStream(blockSender);
}
}
/**
* Receive a block and write it to disk, it then notifies the namenode to
* remove the copy from the source.
*
* @param in The stream to read from
* @throws IOException
*/
private void replaceBlock(DataInputStream in) throws IOException {
/* read header */
long blockId = in.readLong();
Block block = new Block(blockId, dataXceiverServer.estimateBlockSize,
in.readLong()); // block id & generation stamp
String sourceID = Text.readString(in); // read del hint
DatanodeInfo proxySource = new DatanodeInfo(); // read proxy source
proxySource.readFields(in);
if (!dataXceiverServer.balanceThrottler.acquire()) { // not able to start
LOG.warn("Not able to receive block " + blockId + " from "
+ s.getRemoteSocketAddress() + " because threads quota is exceeded.");
sendResponse(s, (short)DataTransferProtocol.OP_STATUS_ERROR,
datanode.socketWriteTimeout);
return;
}
Socket proxySock = null;
DataOutputStream proxyOut = null;
short opStatus = DataTransferProtocol.OP_STATUS_SUCCESS;
BlockReceiver blockReceiver = null;
DataInputStream proxyReply = null;
try {
// get the output stream to the proxy
InetSocketAddress proxyAddr = NetUtils.createSocketAddr(
proxySource.getName());
proxySock = datanode.newSocket();
NetUtils.connect(proxySock, proxyAddr, datanode.socketTimeout);
proxySock.setSoTimeout(datanode.socketTimeout);
OutputStream baseStream = NetUtils.getOutputStream(proxySock,
datanode.socketWriteTimeout);
proxyOut = new DataOutputStream(
new BufferedOutputStream(baseStream, SMALL_BUFFER_SIZE));
/* send request to the proxy */
proxyOut.writeShort(DataTransferProtocol.DATA_TRANSFER_VERSION); // transfer version
proxyOut.writeByte(DataTransferProtocol.OP_COPY_BLOCK); // op code
proxyOut.writeLong(block.getBlockId()); // block id
proxyOut.writeLong(block.getGenerationStamp()); // block id
proxyOut.flush();
// receive the response from the proxy
proxyReply = new DataInputStream(new BufferedInputStream(
NetUtils.getInputStream(proxySock), BUFFER_SIZE));
// open a block receiver and check if the block does not exist
blockReceiver = new BlockReceiver(
block, proxyReply, proxySock.getRemoteSocketAddress().toString(),
proxySock.getLocalSocketAddress().toString(),
false, "", null, datanode);
// receive a block
blockReceiver.receiveBlock(null, null, null, null,
dataXceiverServer.balanceThrottler, -1);
// notify name node
datanode.notifyNamenodeReceivedBlock(block, sourceID);
LOG.info("Moved block " + block +
" from " + s.getRemoteSocketAddress());
} catch (IOException ioe) {
opStatus = DataTransferProtocol.OP_STATUS_ERROR;
throw ioe;
} finally {
// receive the last byte that indicates the proxy released its thread resource
if (opStatus == DataTransferProtocol.OP_STATUS_SUCCESS) {
try {
proxyReply.readChar();
} catch (IOException ignored) {
}
}
// now release the thread resource
dataXceiverServer.balanceThrottler.release();
// send response back
try {
sendResponse(s, opStatus, datanode.socketWriteTimeout);
} catch (IOException ioe) {
LOG.warn("Error writing reply back to " + s.getRemoteSocketAddress());
}
IOUtils.closeStream(proxyOut);
IOUtils.closeStream(blockReceiver);
IOUtils.closeStream(proxyReply);
}
}
/**
* Utility function for sending a response.
* @param s socket to write to
* @param opStatus status message to write
* @param timeout send timeout
**/
private void sendResponse(Socket s, short opStatus, long timeout)
throws IOException {
DataOutputStream reply =
new DataOutputStream(NetUtils.getOutputStream(s, timeout));
try {
reply.writeShort(opStatus);
reply.flush();
} finally {
IOUtils.closeStream(reply);
}
}
}