/**
* 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.fsdataset.impl;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.util.Scanner;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.DU;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.server.datanode.BlockMetadataHeader;
import org.apache.hadoop.hdfs.server.datanode.DataStorage;
import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil;
import org.apache.hadoop.hdfs.server.datanode.FinalizedReplica;
import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo;
import org.apache.hadoop.hdfs.server.datanode.ReplicaBeingWritten;
import org.apache.hadoop.hdfs.server.datanode.ReplicaWaitingToBeRecovered;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.util.DataChecksum;
import org.apache.hadoop.util.DiskChecker;
import org.apache.hadoop.util.DiskChecker.DiskErrorException;
import org.apache.hadoop.util.ShutdownHookManager;
import org.apache.hadoop.util.Time;
/**
* A block pool slice represents a portion of a block pool stored on a volume.
* Taken together, all BlockPoolSlices sharing a block pool ID across a
* cluster represent a single block pool.
*
* This class is synchronized by {@link FsVolumeImpl}.
*/
class BlockPoolSlice {
private final String bpid;
private final FsVolumeImpl volume; // volume to which this BlockPool belongs to
private final File currentDir; // StorageDirectory/current/bpid/current
private final LDir finalizedDir; // directory store Finalized replica
private final File rbwDir; // directory store RBW replica
private final File tmpDir; // directory store Temporary replica
private static final String DU_CACHE_FILE = "dfsUsed";
private volatile boolean dfsUsedSaved = false;
private static final int SHUTDOWN_HOOK_PRIORITY = 30;
// TODO:FEDERATION scalability issue - a thread per DU is needed
private final DU dfsUsage;
/**
* Create a blook pool slice
* @param bpid Block pool Id
* @param volume {@link FsVolumeImpl} to which this BlockPool belongs to
* @param bpDir directory corresponding to the BlockPool
* @param conf
* @throws IOException
*/
BlockPoolSlice(String bpid, FsVolumeImpl volume, File bpDir,
Configuration conf) throws IOException {
this.bpid = bpid;
this.volume = volume;
this.currentDir = new File(bpDir, DataStorage.STORAGE_DIR_CURRENT);
final File finalizedDir = new File(
currentDir, DataStorage.STORAGE_DIR_FINALIZED);
// Files that were being written when the datanode was last shutdown
// are now moved back to the data directory. It is possible that
// in the future, we might want to do some sort of datanode-local
// recovery for these blocks. For example, crc validation.
//
this.tmpDir = new File(bpDir, DataStorage.STORAGE_DIR_TMP);
if (tmpDir.exists()) {
FileUtil.fullyDelete(tmpDir);
}
this.rbwDir = new File(currentDir, DataStorage.STORAGE_DIR_RBW);
final boolean supportAppends = conf.getBoolean(
DFSConfigKeys.DFS_SUPPORT_APPEND_KEY,
DFSConfigKeys.DFS_SUPPORT_APPEND_DEFAULT);
if (rbwDir.exists() && !supportAppends) {
FileUtil.fullyDelete(rbwDir);
}
final int maxBlocksPerDir = conf.getInt(
DFSConfigKeys.DFS_DATANODE_NUMBLOCKS_KEY,
DFSConfigKeys.DFS_DATANODE_NUMBLOCKS_DEFAULT);
this.finalizedDir = new LDir(finalizedDir, maxBlocksPerDir);
if (!rbwDir.mkdirs()) { // create rbw directory if not exist
if (!rbwDir.isDirectory()) {
throw new IOException("Mkdirs failed to create " + rbwDir.toString());
}
}
if (!tmpDir.mkdirs()) {
if (!tmpDir.isDirectory()) {
throw new IOException("Mkdirs failed to create " + tmpDir.toString());
}
}
// Use cached value initially if available. Or the following call will
// block until the initial du command completes.
this.dfsUsage = new DU(bpDir, conf, loadDfsUsed());
this.dfsUsage.start();
// Make the dfs usage to be saved during shutdown.
ShutdownHookManager.get().addShutdownHook(
new Runnable() {
@Override
public void run() {
if (!dfsUsedSaved) {
saveDfsUsed();
}
}
}, SHUTDOWN_HOOK_PRIORITY);
}
File getDirectory() {
return currentDir.getParentFile();
}
File getFinalizedDir() {
return finalizedDir.dir;
}
File getRbwDir() {
return rbwDir;
}
/** Run DU on local drives. It must be synchronized from caller. */
void decDfsUsed(long value) {
dfsUsage.decDfsUsed(value);
}
long getDfsUsed() throws IOException {
return dfsUsage.getUsed();
}
/**
* Read in the cached DU value and return it if it is less than 600 seconds
* old (DU update interval). Slight imprecision of dfsUsed is not critical
* and skipping DU can significantly shorten the startup time.
* If the cached value is not available or too old, -1 is returned.
*/
long loadDfsUsed() {
long cachedDfsUsed;
long mtime;
Scanner sc;
try {
sc = new Scanner(new File(currentDir, DU_CACHE_FILE));
} catch (FileNotFoundException fnfe) {
return -1;
}
try {
// Get the recorded dfsUsed from the file.
if (sc.hasNextLong()) {
cachedDfsUsed = sc.nextLong();
} else {
return -1;
}
// Get the recorded mtime from the file.
if (sc.hasNextLong()) {
mtime = sc.nextLong();
} else {
return -1;
}
// Return the cached value if mtime is okay.
if (mtime > 0 && (Time.now() - mtime < 600000L)) {
FsDatasetImpl.LOG.info("Cached dfsUsed found for " + currentDir + ": " +
cachedDfsUsed);
return cachedDfsUsed;
}
return -1;
} finally {
sc.close();
}
}
/**
* Write the current dfsUsed to the cache file.
*/
void saveDfsUsed() {
File outFile = new File(currentDir, DU_CACHE_FILE);
if (outFile.exists() && !outFile.delete()) {
FsDatasetImpl.LOG.warn("Failed to delete old dfsUsed file in " +
outFile.getParent());
}
FileWriter out = null;
try {
long used = getDfsUsed();
if (used > 0) {
out = new FileWriter(outFile);
// mtime is written last, so that truncated writes won't be valid.
out.write(Long.toString(used) + " " + Long.toString(Time.now()));
out.flush();
out.close();
out = null;
}
} catch (IOException ioe) {
// If write failed, the volume might be bad. Since the cache file is
// not critical, log the error and continue.
FsDatasetImpl.LOG.warn("Failed to write dfsUsed to " + outFile, ioe);
} finally {
IOUtils.cleanup(null, out);
}
}
/**
* Temporary files. They get moved to the finalized block directory when
* the block is finalized.
*/
File createTmpFile(Block b) throws IOException {
File f = new File(tmpDir, b.getBlockName());
return DatanodeUtil.createTmpFile(b, f);
}
/**
* RBW files. They get moved to the finalized block directory when
* the block is finalized.
*/
File createRbwFile(Block b) throws IOException {
File f = new File(rbwDir, b.getBlockName());
return DatanodeUtil.createTmpFile(b, f);
}
File addBlock(Block b, File f) throws IOException {
File blockFile = finalizedDir.addBlock(b, f);
File metaFile = FsDatasetUtil.getMetaFile(blockFile, b.getGenerationStamp());
dfsUsage.incDfsUsed(b.getNumBytes()+metaFile.length());
return blockFile;
}
void checkDirs() throws DiskErrorException {
finalizedDir.checkDirTree();
DiskChecker.checkDir(tmpDir);
DiskChecker.checkDir(rbwDir);
}
void getVolumeMap(ReplicaMap volumeMap) throws IOException {
// add finalized replicas
finalizedDir.getVolumeMap(bpid, volumeMap, volume);
// add rbw replicas
addToReplicasMap(volumeMap, rbwDir, false);
}
/**
* Add replicas under the given directory to the volume map
* @param volumeMap the replicas map
* @param dir an input directory
* @param isFinalized true if the directory has finalized replicas;
* false if the directory has rbw replicas
*/
void addToReplicasMap(ReplicaMap volumeMap, File dir, boolean isFinalized
) throws IOException {
File blockFiles[] = FileUtil.listFiles(dir);
for (File blockFile : blockFiles) {
if (!Block.isBlockFilename(blockFile))
continue;
long genStamp = FsDatasetUtil.getGenerationStampFromFile(
blockFiles, blockFile);
long blockId = Block.filename2id(blockFile.getName());
ReplicaInfo newReplica = null;
if (isFinalized) {
newReplica = new FinalizedReplica(blockId,
blockFile.length(), genStamp, volume, blockFile.getParentFile());
} else {
boolean loadRwr = true;
File restartMeta = new File(blockFile.getParent() +
File.pathSeparator + "." + blockFile.getName() + ".restart");
Scanner sc = null;
try {
sc = new Scanner(restartMeta);
// The restart meta file exists
if (sc.hasNextLong() && (sc.nextLong() > Time.now())) {
// It didn't expire. Load the replica as a RBW.
newReplica = new ReplicaBeingWritten(blockId,
validateIntegrityAndSetLength(blockFile, genStamp),
genStamp, volume, blockFile.getParentFile(), null);
loadRwr = false;
}
sc.close();
if (restartMeta.delete()) {
FsDatasetImpl.LOG.warn("Failed to delete restart meta file: " +
restartMeta.getPath());
}
} catch (FileNotFoundException fnfe) {
// nothing to do here
} finally {
if (sc != null) {
sc.close();
}
}
// Restart meta doesn't exist or expired.
if (loadRwr) {
newReplica = new ReplicaWaitingToBeRecovered(blockId,
validateIntegrityAndSetLength(blockFile, genStamp),
genStamp, volume, blockFile.getParentFile());
}
}
ReplicaInfo oldReplica = volumeMap.add(bpid, newReplica);
if (oldReplica != null) {
FsDatasetImpl.LOG.warn("Two block files with the same block id exist " +
"on disk: " + oldReplica.getBlockFile() + " and " + blockFile );
}
}
}
/**
* Find out the number of bytes in the block that match its crc.
*
* This algorithm assumes that data corruption caused by unexpected
* datanode shutdown occurs only in the last crc chunk. So it checks
* only the last chunk.
*
* @param blockFile the block file
* @param genStamp generation stamp of the block
* @return the number of valid bytes
*/
private long validateIntegrityAndSetLength(File blockFile, long genStamp) {
DataInputStream checksumIn = null;
InputStream blockIn = null;
try {
final File metaFile = FsDatasetUtil.getMetaFile(blockFile, genStamp);
long blockFileLen = blockFile.length();
long metaFileLen = metaFile.length();
int crcHeaderLen = DataChecksum.getChecksumHeaderSize();
if (!blockFile.exists() || blockFileLen == 0 ||
!metaFile.exists() || metaFileLen < crcHeaderLen) {
return 0;
}
checksumIn = new DataInputStream(
new BufferedInputStream(new FileInputStream(metaFile),
HdfsConstants.IO_FILE_BUFFER_SIZE));
// read and handle the common header here. For now just a version
BlockMetadataHeader header = BlockMetadataHeader.readHeader(checksumIn);
short version = header.getVersion();
if (version != BlockMetadataHeader.VERSION) {
FsDatasetImpl.LOG.warn("Wrong version (" + version + ") for metadata file "
+ metaFile + " ignoring ...");
}
DataChecksum checksum = header.getChecksum();
int bytesPerChecksum = checksum.getBytesPerChecksum();
int checksumSize = checksum.getChecksumSize();
long numChunks = Math.min(
(blockFileLen + bytesPerChecksum - 1)/bytesPerChecksum,
(metaFileLen - crcHeaderLen)/checksumSize);
if (numChunks == 0) {
return 0;
}
IOUtils.skipFully(checksumIn, (numChunks-1)*checksumSize);
blockIn = new FileInputStream(blockFile);
long lastChunkStartPos = (numChunks-1)*bytesPerChecksum;
IOUtils.skipFully(blockIn, lastChunkStartPos);
int lastChunkSize = (int)Math.min(
bytesPerChecksum, blockFileLen-lastChunkStartPos);
byte[] buf = new byte[lastChunkSize+checksumSize];
checksumIn.readFully(buf, lastChunkSize, checksumSize);
IOUtils.readFully(blockIn, buf, 0, lastChunkSize);
checksum.update(buf, 0, lastChunkSize);
long validFileLength;
if (checksum.compare(buf, lastChunkSize)) { // last chunk matches crc
validFileLength = lastChunkStartPos + lastChunkSize;
} else { // last chunck is corrupt
validFileLength = lastChunkStartPos;
}
// truncate if extra bytes are present without CRC
if (blockFile.length() > validFileLength) {
RandomAccessFile blockRAF = new RandomAccessFile(blockFile, "rw");
try {
// truncate blockFile
blockRAF.setLength(validFileLength);
} finally {
blockRAF.close();
}
}
return validFileLength;
} catch (IOException e) {
FsDatasetImpl.LOG.warn(e);
return 0;
} finally {
IOUtils.closeStream(checksumIn);
IOUtils.closeStream(blockIn);
}
}
void clearPath(File f) {
finalizedDir.clearPath(f);
}
@Override
public String toString() {
return currentDir.getAbsolutePath();
}
void shutdown() {
saveDfsUsed();
dfsUsedSaved = true;
dfsUsage.shutdown();
}
}