/**
* 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.IOException;
import java.util.TreeMap;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
import com.google.common.annotations.VisibleForTesting;
/**
* DataBlockScanner manages block scanning for all the block pools. For each
* block pool a {@link BlockPoolSliceScanner} is created which runs in a separate
* thread to scan the blocks for that block pool. When a {@link BPOfferService}
* becomes alive or dies, blockPoolScannerMap in this class is updated.
*/
@InterfaceAudience.Private
public class DataBlockScanner implements Runnable {
public static final Log LOG = LogFactory.getLog(DataBlockScanner.class);
private final DataNode datanode;
private final FsDatasetSpi<? extends FsVolumeSpi> dataset;
private final Configuration conf;
static final int SLEEP_PERIOD_MS = 5 * 1000;
/**
* Map to find the BlockPoolScanner for a given block pool id. This is updated
* when a BPOfferService becomes alive or dies.
*/
private final TreeMap<String, BlockPoolSliceScanner> blockPoolScannerMap =
new TreeMap<String, BlockPoolSliceScanner>();
Thread blockScannerThread = null;
DataBlockScanner(DataNode datanode,
FsDatasetSpi<? extends FsVolumeSpi> dataset,
Configuration conf) {
this.datanode = datanode;
this.dataset = dataset;
this.conf = conf;
}
@Override
public void run() {
String currentBpId = "";
boolean firstRun = true;
while (datanode.shouldRun && !Thread.interrupted()) {
//Sleep everytime except in the first iteration.
if (!firstRun) {
try {
Thread.sleep(SLEEP_PERIOD_MS);
} catch (InterruptedException ex) {
// Interrupt itself again to set the interrupt status
blockScannerThread.interrupt();
continue;
}
} else {
firstRun = false;
}
BlockPoolSliceScanner bpScanner = getNextBPScanner(currentBpId);
if (bpScanner == null) {
// Possible if thread is interrupted
continue;
}
currentBpId = bpScanner.getBlockPoolId();
// If BPOfferService for this pool is not alive, don't process it
if (!datanode.isBPServiceAlive(currentBpId)) {
LOG.warn("Block Pool " + currentBpId + " is not alive");
// Remove in case BP service died abruptly without proper shutdown
removeBlockPool(currentBpId);
continue;
}
bpScanner.scanBlockPoolSlice();
}
// Call shutdown for each allocated BlockPoolSliceScanner.
for (BlockPoolSliceScanner bpss: blockPoolScannerMap.values()) {
bpss.shutdown();
}
}
// Wait for at least one block pool to be up
private void waitForInit() {
while ((getBlockPoolSetSize() < datanode.getAllBpOs().length)
|| (getBlockPoolSetSize() < 1)) {
try {
Thread.sleep(SLEEP_PERIOD_MS);
} catch (InterruptedException e) {
blockScannerThread.interrupt();
return;
}
}
}
/**
* Find next block pool id to scan. There should be only one current
* verification log file. Find which block pool contains the current
* verification log file and that is used as the starting block pool id. If no
* current files are found start with first block-pool in the blockPoolSet.
* However, if more than one current files are found, the one with latest
* modification time is used to find the next block pool id.
*/
private BlockPoolSliceScanner getNextBPScanner(String currentBpId) {
String nextBpId = null;
while ((nextBpId == null) && datanode.shouldRun
&& !blockScannerThread.isInterrupted()) {
waitForInit();
synchronized (this) {
if (getBlockPoolSetSize() > 0) {
// Find nextBpId by the minimum of the last scan time
long lastScanTime = 0;
for (String bpid : blockPoolScannerMap.keySet()) {
final long t = getBPScanner(bpid).getLastScanTime();
if (t != 0L) {
if (bpid == null || t < lastScanTime) {
lastScanTime = t;
nextBpId = bpid;
}
}
}
// nextBpId can still be null if no current log is found,
// find nextBpId sequentially.
if (nextBpId == null) {
nextBpId = blockPoolScannerMap.higherKey(currentBpId);
if (nextBpId == null) {
nextBpId = blockPoolScannerMap.firstKey();
}
}
if (nextBpId != null) {
return getBPScanner(nextBpId);
}
}
}
LOG.warn("No block pool is up, going to wait");
try {
Thread.sleep(5000);
} catch (InterruptedException ex) {
LOG.warn("Received exception: " + ex);
blockScannerThread.interrupt();
return null;
}
}
return null;
}
private synchronized int getBlockPoolSetSize() {
return blockPoolScannerMap.size();
}
@VisibleForTesting
synchronized BlockPoolSliceScanner getBPScanner(String bpid) {
return blockPoolScannerMap.get(bpid);
}
private synchronized String[] getBpIdList() {
return blockPoolScannerMap.keySet().toArray(
new String[blockPoolScannerMap.keySet().size()]);
}
public void addBlock(ExtendedBlock block) {
BlockPoolSliceScanner bpScanner = getBPScanner(block.getBlockPoolId());
if (bpScanner != null) {
bpScanner.addBlock(block);
} else {
LOG.warn("No block pool scanner found for block pool id: "
+ block.getBlockPoolId());
}
}
boolean isInitialized(String bpid) {
return getBPScanner(bpid) != null;
}
public synchronized void printBlockReport(StringBuilder buffer,
boolean summary) {
String[] bpIdList = getBpIdList();
if (bpIdList == null || bpIdList.length == 0) {
buffer.append("Periodic block scanner is not yet initialized. "
+ "Please check back again after some time.");
return;
}
for (String bpid : bpIdList) {
BlockPoolSliceScanner bpScanner = getBPScanner(bpid);
buffer.append("\n\nBlock report for block pool: "+bpid + "\n");
bpScanner.printBlockReport(buffer, summary);
buffer.append("\n");
}
}
public void deleteBlock(String poolId, Block toDelete) {
BlockPoolSliceScanner bpScanner = getBPScanner(poolId);
if (bpScanner != null) {
bpScanner.deleteBlock(toDelete);
} else {
LOG.warn("No block pool scanner found for block pool id: "
+ poolId);
}
}
public void deleteBlocks(String poolId, Block[] toDelete) {
BlockPoolSliceScanner bpScanner = getBPScanner(poolId);
if (bpScanner != null) {
bpScanner.deleteBlocks(toDelete);
} else {
LOG.warn("No block pool scanner found for block pool id: "
+ poolId);
}
}
public void shutdown() {
synchronized (this) {
if (blockScannerThread != null) {
blockScannerThread.interrupt();
}
}
// We cannot join within the synchronized block, because it would create a
// deadlock situation. blockScannerThread calls other synchronized methods.
if (blockScannerThread != null) {
try {
blockScannerThread.join();
} catch (InterruptedException e) {
// shutting down anyway
}
}
}
public synchronized void addBlockPool(String blockPoolId) {
if (blockPoolScannerMap.get(blockPoolId) != null) {
return;
}
BlockPoolSliceScanner bpScanner = new BlockPoolSliceScanner(blockPoolId,
datanode, dataset, conf);
blockPoolScannerMap.put(blockPoolId, bpScanner);
LOG.info("Added bpid=" + blockPoolId + " to blockPoolScannerMap, new size="
+ blockPoolScannerMap.size());
}
public synchronized void removeBlockPool(String blockPoolId) {
BlockPoolSliceScanner bpss = blockPoolScannerMap.remove(blockPoolId);
if (bpss != null) {
bpss.shutdown();
}
LOG.info("Removed bpid="+blockPoolId+" from blockPoolScannerMap");
}
@VisibleForTesting
long getBlocksScannedInLastRun(String bpid) throws IOException {
BlockPoolSliceScanner bpScanner = getBPScanner(bpid);
if (bpScanner == null) {
throw new IOException("Block Pool: "+bpid+" is not running");
} else {
return bpScanner.getBlocksScannedInLastRun();
}
}
@VisibleForTesting
long getTotalScans(String bpid) throws IOException {
BlockPoolSliceScanner bpScanner = getBPScanner(bpid);
if (bpScanner == null) {
throw new IOException("Block Pool: "+bpid+" is not running");
} else {
return bpScanner.getTotalScans();
}
}
public void start() {
blockScannerThread = new Thread(this);
blockScannerThread.setDaemon(true);
blockScannerThread.start();
}
@InterfaceAudience.Private
public static class Servlet extends HttpServlet {
private static final long serialVersionUID = 1L;
@Override
public void doGet(HttpServletRequest request,
HttpServletResponse response) throws IOException {
response.setContentType("text/plain");
DataNode datanode = (DataNode) getServletContext().getAttribute("datanode");
DataBlockScanner blockScanner = datanode.blockScanner;
boolean summary = (request.getParameter("listblocks") == null);
StringBuilder buffer = new StringBuilder(8*1024);
if (blockScanner == null) {
LOG.warn("Periodic block scanner is not running");
buffer.append("Periodic block scanner is not running. " +
"Please check the datanode log if this is unexpected.");
} else {
blockScanner.printBlockReport(buffer, summary);
}
response.getWriter().write(buffer.toString()); // extra copy!
}
}
}