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/**
* 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;
import java.io.IOException;
import java.util.EnumSet;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.hdfs.DFSStripedOutputStream.Coordinator;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
import org.apache.hadoop.hdfs.protocol.LocatedBlock;
import org.apache.hadoop.hdfs.server.datanode.CachingStrategy;
import org.apache.hadoop.hdfs.util.ByteArrayManager;
import org.apache.hadoop.util.DataChecksum;
import org.apache.hadoop.util.Progressable;
import com.google.common.annotations.VisibleForTesting;
/**
* This class extends {@link DataStreamer} to support writing striped blocks
* to datanodes.
* A {@link DFSStripedOutputStream} has multiple {@link StripedDataStreamer}s.
* Whenever the streamers need to talk the namenode, only the fastest streamer
* sends an rpc call to the namenode and then populates the result for the
* other streamers.
*/
@InterfaceAudience.Private
public class StripedDataStreamer extends DataStreamer {
private final Coordinator coordinator;
private final int index;
StripedDataStreamer(HdfsFileStatus stat,
DFSClient dfsClient, String src,
Progressable progress, DataChecksum checksum,
AtomicReference cachingStrategy,
ByteArrayManager byteArrayManage, String[] favoredNodes,
short index, Coordinator coordinator,
final EnumSet flags) {
super(stat, null, dfsClient, src, progress, checksum, cachingStrategy,
byteArrayManage, favoredNodes, flags);
this.index = index;
this.coordinator = coordinator;
}
int getIndex() {
return index;
}
boolean isHealthy() {
return !streamerClosed() && !getErrorState().hasInternalError();
}
@Override
protected void endBlock() {
coordinator.offerEndBlock(index, block.getCurrentBlock());
super.endBlock();
}
/**
* The upper level DFSStripedOutputStream will allocate the new block group.
* All the striped data streamer only needs to fetch from the queue, which
* should be already be ready.
*/
private LocatedBlock getFollowingBlock() throws IOException {
if (!this.isHealthy()) {
// No internal block for this streamer, maybe no enough healthy DN.
// Throw the exception which has been set by the StripedOutputStream.
this.getLastException().check(false);
}
return coordinator.getFollowingBlocks().poll(index);
}
@Override
protected LocatedBlock nextBlockOutputStream() throws IOException {
boolean success;
LocatedBlock lb = getFollowingBlock();
block.setCurrentBlock(lb.getBlock());
block.setNumBytes(0);
bytesSent = 0;
accessToken = lb.getBlockToken();
DatanodeInfo[] nodes = lb.getLocations();
StorageType[] storageTypes = lb.getStorageTypes();
String[] storageIDs = lb.getStorageIDs();
// Connect to the DataNode. If fail the internal error state will be set.
success = createBlockOutputStream(nodes, storageTypes, storageIDs, 0L,
false);
if (!success) {
block.setCurrentBlock(null);
final DatanodeInfo badNode = nodes[getErrorState().getBadNodeIndex()];
LOG.warn("Excluding datanode " + badNode);
excludedNodes.put(badNode, badNode);
throw new IOException("Unable to create new block." + this);
}
return lb;
}
@VisibleForTesting
LocatedBlock peekFollowingBlock() {
return coordinator.getFollowingBlocks().peek(index);
}
@Override
protected void setupPipelineInternal(DatanodeInfo[] nodes,
StorageType[] nodeStorageTypes, String[] nodeStorageIDs)
throws IOException {
boolean success = false;
while (!success && !streamerClosed() && dfsClient.clientRunning) {
if (!handleRestartingDatanode()) {
return;
}
if (!handleBadDatanode()) {
// for striped streamer if it is datanode error then close the stream
// and return. no need to replace datanode
return;
}
// get a new generation stamp and an access token
final LocatedBlock lb = coordinator.getNewBlocks().take(index);
long newGS = lb.getBlock().getGenerationStamp();
setAccessToken(lb.getBlockToken());
// set up the pipeline again with the remaining nodes. when a striped
// data streamer comes here, it must be in external error state.
assert getErrorState().hasExternalError();
success = createBlockOutputStream(nodes, nodeStorageTypes,
nodeStorageIDs, newGS, true);
failPacket4Testing();
getErrorState().checkRestartingNodeDeadline(nodes);
// notify coordinator the result of createBlockOutputStream
synchronized (coordinator) {
if (!streamerClosed()) {
coordinator.updateStreamer(this, success);
coordinator.notify();
} else {
success = false;
}
}
if (success) {
// wait for results of other streamers
success = coordinator.takeStreamerUpdateResult(index);
if (success) {
// if all succeeded, update its block using the new GS
updateBlockGS(newGS);
} else {
// otherwise close the block stream and restart the recovery process
closeStream();
}
} else {
// if fail, close the stream. The internal error state and last
// exception have already been set in createBlockOutputStream
// TODO: wait for restarting DataNodes during RollingUpgrade
closeStream();
setStreamerAsClosed();
}
} // while
}
void setExternalError() {
getErrorState().setExternalError();
synchronized (dataQueue) {
dataQueue.notifyAll();
}
}
@Override
public String toString() {
return "#" + index + ": " + (!isHealthy() ? "failed, ": "") + super.toString();
}
}
