/**
* 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.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Random;
import javax.management.NotCompliantMBeanException;
import javax.management.ObjectName;
import javax.management.StandardMBean;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.FSConstants;
import org.apache.hadoop.hdfs.server.datanode.metrics.FSDatasetMBean;
import org.apache.hadoop.metrics.util.MBeanUtil;
import org.apache.hadoop.util.DataChecksum;
import org.apache.hadoop.util.DiskChecker.DiskErrorException;
/**
* This class implements a simulated FSDataset.
*
* Blocks that are created are recorded but their data (plus their CRCs) are
* discarded.
* Fixed data is returned when blocks are read; a null CRC meta file is
* created for such data.
*
* This FSDataset does not remember any block information across its
* restarts; it does however offer an operation to inject blocks
* (See the TestInectionForSImulatedStorage()
* for a usage example of injection.
*
* Note the synchronization is coarse grained - it is at each method.
*/
public class SimulatedFSDataset implements FSConstants, FSDatasetInterface, Configurable{
public static final String CONFIG_PROPERTY_SIMULATED =
"dfs.datanode.simulateddatastorage";
public static final String CONFIG_PROPERTY_CAPACITY =
"dfs.datanode.simulateddatastorage.capacity";
public static final long DEFAULT_CAPACITY = 2L<<40; // 1 terabyte
public static final byte DEFAULT_DATABYTE = 9; // 1 terabyte
byte simulatedDataByte = DEFAULT_DATABYTE;
Configuration conf = null;
static byte[] nullCrcFileData;
{
DataChecksum checksum = DataChecksum.newDataChecksum( DataChecksum.
CHECKSUM_NULL, 16*1024 );
byte[] nullCrcHeader = checksum.getHeader();
nullCrcFileData = new byte[2 + nullCrcHeader.length];
nullCrcFileData[0] = (byte) ((FSDataset.METADATA_VERSION >>> 8) & 0xff);
nullCrcFileData[1] = (byte) (FSDataset.METADATA_VERSION & 0xff);
for (int i = 0; i < nullCrcHeader.length; i++) {
nullCrcFileData[i+2] = nullCrcHeader[i];
}
}
private class BInfo { // information about a single block
Block theBlock;
private boolean finalized = false; // if not finalized => ongoing creation
SimulatedOutputStream oStream = null;
BInfo(Block b, boolean forWriting) throws IOException {
theBlock = new Block(b);
if (theBlock.getNumBytes() < 0) {
theBlock.setNumBytes(0);
}
if (!storage.alloc(theBlock.getNumBytes())) { // expected length - actual length may
// be more - we find out at finalize
DataNode.LOG.warn("Lack of free storage on a block alloc");
throw new IOException("Creating block, no free space available");
}
if (forWriting) {
finalized = false;
oStream = new SimulatedOutputStream();
} else {
finalized = true;
oStream = null;
}
}
synchronized long getGenerationStamp() {
return theBlock.getGenerationStamp();
}
synchronized void updateBlock(Block b) {
theBlock.setGenerationStamp(b.getGenerationStamp());
setlength(b.getNumBytes());
}
synchronized long getlength() {
if (!finalized) {
return oStream.getLength();
} else {
return theBlock.getNumBytes();
}
}
synchronized void setlength(long length) {
if (!finalized) {
oStream.setLength(length);
} else {
theBlock.setNumBytes(length);
}
}
synchronized SimulatedInputStream getIStream() throws IOException {
if (!finalized) {
// throw new IOException("Trying to read an unfinalized block");
return new SimulatedInputStream(oStream.getLength(), DEFAULT_DATABYTE);
} else {
return new SimulatedInputStream(theBlock.getNumBytes(), DEFAULT_DATABYTE);
}
}
synchronized void finalizeBlock(long finalSize) throws IOException {
if (finalized) {
throw new IOException(
"Finalizing a block that has already been finalized" +
theBlock.getBlockId());
}
if (oStream == null) {
DataNode.LOG.error("Null oStream on unfinalized block - bug");
throw new IOException("Unexpected error on finalize");
}
if (oStream.getLength() != finalSize) {
DataNode.LOG.warn("Size passed to finalize (" + finalSize +
")does not match what was written:" + oStream.getLength());
throw new IOException(
"Size passed to finalize does not match the amount of data written");
}
// We had allocated the expected length when block was created;
// adjust if necessary
long extraLen = finalSize - theBlock.getNumBytes();
if (extraLen > 0) {
if (!storage.alloc(extraLen)) {
DataNode.LOG.warn("Lack of free storage on a block alloc");
throw new IOException("Creating block, no free space available");
}
} else {
storage.free(-extraLen);
}
theBlock.setNumBytes(finalSize);
finalized = true;
oStream = null;
return;
}
SimulatedInputStream getMetaIStream() {
return new SimulatedInputStream(nullCrcFileData);
}
synchronized boolean isFinalized() {
return finalized;
}
}
static private class SimulatedStorage {
private long capacity; // in bytes
private long used; // in bytes
synchronized long getFree() {
return capacity - used;
}
synchronized long getCapacity() {
return capacity;
}
synchronized long getUsed() {
return used;
}
synchronized boolean alloc(long amount) {
if (getFree() >= amount) {
used += amount;
return true;
} else {
return false;
}
}
synchronized void free(long amount) {
used -= amount;
}
SimulatedStorage(long cap) {
capacity = cap;
used = 0;
}
}
private HashMap<Block, BInfo> blockMap = null;
private SimulatedStorage storage = null;
private String storageId;
public SimulatedFSDataset(Configuration conf) throws IOException {
setConf(conf);
}
private SimulatedFSDataset() { // real construction when setConf called.. Uggg
}
public Configuration getConf() {
return conf;
}
public void setConf(Configuration iconf) {
conf = iconf;
storageId = conf.get("StorageId", "unknownStorageId" +
new Random().nextInt());
registerMBean(storageId);
storage = new SimulatedStorage(
conf.getLong(CONFIG_PROPERTY_CAPACITY, DEFAULT_CAPACITY));
//DataNode.LOG.info("Starting Simulated storage; Capacity = " + getCapacity() +
// "Used = " + getDfsUsed() + "Free =" + getRemaining());
blockMap = new HashMap<Block,BInfo>();
}
public synchronized void injectBlocks(Block[] injectBlocks)
throws IOException {
if (injectBlocks != null) {
for (Block b: injectBlocks) { // if any blocks in list is bad, reject list
if (b == null) {
throw new NullPointerException("Null blocks in block list");
}
if (isValidBlock(b)) {
throw new IOException("Block already exists in block list");
}
}
HashMap<Block, BInfo> oldBlockMap = blockMap;
blockMap =
new HashMap<Block,BInfo>(injectBlocks.length + oldBlockMap.size());
blockMap.putAll(oldBlockMap);
for (Block b: injectBlocks) {
BInfo binfo = new BInfo(b, false);
blockMap.put(b, binfo);
}
}
}
public synchronized void finalizeBlock(Block b) throws IOException {
BInfo binfo = blockMap.get(b);
if (binfo == null) {
throw new IOException("Finalizing a non existing block " + b);
}
binfo.finalizeBlock(b.getNumBytes());
}
public synchronized void unfinalizeBlock(Block b) throws IOException {
if (isBeingWritten(b)) {
blockMap.remove(b);
}
}
public synchronized Block[] getBlockReport() {
Block[] blockTable = new Block[blockMap.size()];
int count = 0;
for (BInfo b : blockMap.values()) {
if (b.isFinalized()) {
blockTable[count++] = b.theBlock;
}
}
if (count != blockTable.length) {
blockTable = Arrays.copyOf(blockTable, count);
}
return blockTable;
}
public long getCapacity() throws IOException {
return storage.getCapacity();
}
public long getDfsUsed() throws IOException {
return storage.getUsed();
}
public long getRemaining() throws IOException {
return storage.getFree();
}
public synchronized long getLength(Block b) throws IOException {
BInfo binfo = blockMap.get(b);
if (binfo == null) {
throw new IOException("Finalizing a non existing block " + b);
}
return binfo.getlength();
}
/** {@inheritDoc} */
public Block getStoredBlock(long blkid) throws IOException {
Block b = new Block(blkid);
BInfo binfo = blockMap.get(b);
if (binfo == null) {
return null;
}
b.setGenerationStamp(binfo.getGenerationStamp());
b.setNumBytes(binfo.getlength());
return b;
}
/** {@inheritDoc} */
public void updateBlock(Block oldblock, Block newblock) throws IOException {
BInfo binfo = blockMap.get(newblock);
if (binfo == null) {
throw new IOException("BInfo not found, b=" + newblock);
}
binfo.updateBlock(newblock);
}
public synchronized void invalidate(Block[] invalidBlks) throws IOException {
boolean error = false;
if (invalidBlks == null) {
return;
}
for (Block b: invalidBlks) {
if (b == null) {
continue;
}
BInfo binfo = blockMap.get(b);
if (binfo == null) {
error = true;
DataNode.LOG.warn("Invalidate: Missing block");
continue;
}
storage.free(binfo.getlength());
blockMap.remove(b);
}
if (error) {
throw new IOException("Invalidate: Missing blocks.");
}
}
public synchronized boolean isValidBlock(Block b) {
// return (blockMap.containsKey(b));
BInfo binfo = blockMap.get(b);
if (binfo == null) {
return false;
}
return binfo.isFinalized();
}
/* check if a block is created but not finalized */
private synchronized boolean isBeingWritten(Block b) {
BInfo binfo = blockMap.get(b);
if (binfo == null) {
return false;
}
return !binfo.isFinalized();
}
public String toString() {
return getStorageInfo();
}
public synchronized BlockWriteStreams writeToBlock(Block b,
boolean isRecovery)
throws IOException {
if (isValidBlock(b)) {
throw new BlockAlreadyExistsException("Block " + b +
" is valid, and cannot be written to.");
}
if (isBeingWritten(b)) {
throw new BlockAlreadyExistsException("Block " + b +
" is being written, and cannot be written to.");
}
BInfo binfo = new BInfo(b, true);
blockMap.put(b, binfo);
SimulatedOutputStream crcStream = new SimulatedOutputStream();
return new BlockWriteStreams(binfo.oStream, crcStream);
}
public synchronized InputStream getBlockInputStream(Block b)
throws IOException {
BInfo binfo = blockMap.get(b);
if (binfo == null) {
throw new IOException("No such Block " + b );
}
//DataNode.LOG.info("Opening block(" + b.blkid + ") of length " + b.len);
return binfo.getIStream();
}
public synchronized InputStream getBlockInputStream(Block b, long seekOffset)
throws IOException {
InputStream result = getBlockInputStream(b);
result.skip(seekOffset);
return result;
}
/** Not supported */
public BlockInputStreams getTmpInputStreams(Block b, long blkoff, long ckoff
) throws IOException {
throw new IOException("Not supported");
}
/** No-op */
public void validateBlockMetadata(Block b) {
}
/**
* Returns metaData of block b as an input stream
* @param b - the block for which the metadata is desired
* @return metaData of block b as an input stream
* @throws IOException - block does not exist or problems accessing
* the meta file
*/
private synchronized InputStream getMetaDataInStream(Block b)
throws IOException {
BInfo binfo = blockMap.get(b);
if (binfo == null) {
throw new IOException("No such Block " + b );
}
if (!binfo.finalized) {
throw new IOException("Block " + b +
" is being written, its meta cannot be read");
}
return binfo.getMetaIStream();
}
public synchronized long getMetaDataLength(Block b) throws IOException {
BInfo binfo = blockMap.get(b);
if (binfo == null) {
throw new IOException("No such Block " + b );
}
if (!binfo.finalized) {
throw new IOException("Block " + b +
" is being written, its metalength cannot be read");
}
return binfo.getMetaIStream().getLength();
}
public MetaDataInputStream getMetaDataInputStream(Block b)
throws IOException {
return new MetaDataInputStream(getMetaDataInStream(b),
getMetaDataLength(b));
}
public synchronized boolean metaFileExists(Block b) throws IOException {
if (!isValidBlock(b)) {
throw new IOException("Block " + b +
" is valid, and cannot be written to.");
}
return true; // crc exists for all valid blocks
}
public void checkDataDir() throws DiskErrorException {
// nothing to check for simulated data set
}
public synchronized long getChannelPosition(Block b,
BlockWriteStreams stream)
throws IOException {
BInfo binfo = blockMap.get(b);
if (binfo == null) {
throw new IOException("No such Block " + b );
}
return binfo.getlength();
}
public synchronized void setChannelPosition(Block b, BlockWriteStreams stream,
long dataOffset, long ckOffset)
throws IOException {
BInfo binfo = blockMap.get(b);
if (binfo == null) {
throw new IOException("No such Block " + b );
}
binfo.setlength(dataOffset);
}
/**
* Simulated input and output streams
*
*/
static private class SimulatedInputStream extends java.io.InputStream {
byte theRepeatedData = 7;
long length; // bytes
int currentPos = 0;
byte[] data = null;
/**
* An input stream of size l with repeated bytes
* @param l
* @param iRepeatedData
*/
SimulatedInputStream(long l, byte iRepeatedData) {
length = l;
theRepeatedData = iRepeatedData;
}
/**
* An input stream of of the supplied data
*
* @param iData
*/
SimulatedInputStream(byte[] iData) {
data = iData;
length = data.length;
}
/**
*
* @return the lenght of the input stream
*/
long getLength() {
return length;
}
@Override
public int read() throws IOException {
if (currentPos >= length)
return -1;
if (data !=null) {
return data[currentPos++];
} else {
currentPos++;
return theRepeatedData;
}
}
@Override
public int read(byte[] b) throws IOException {
if (b == null) {
throw new NullPointerException();
}
if (b.length == 0) {
return 0;
}
if (currentPos >= length) { // EOF
return -1;
}
int bytesRead = (int) Math.min(b.length, length-currentPos);
if (data != null) {
System.arraycopy(data, currentPos, b, 0, bytesRead);
} else { // all data is zero
for (int i : b) {
b[i] = theRepeatedData;
}
}
currentPos += bytesRead;
return bytesRead;
}
}
/**
* This class implements an output stream that merely throws its data away, but records its
* length.
*
*/
static private class SimulatedOutputStream extends OutputStream {
long length = 0;
/**
* constructor for Simulated Output Steram
*/
SimulatedOutputStream() {
}
/**
*
* @return the length of the data created so far.
*/
long getLength() {
return length;
}
/**
*/
void setLength(long length) {
this.length = length;
}
@Override
public void write(int arg0) throws IOException {
length++;
}
@Override
public void write(byte[] b) throws IOException {
length += b.length;
}
@Override
public void write(byte[] b,
int off,
int len) throws IOException {
length += len;
}
}
private ObjectName mbeanName;
/**
* Register the FSDataset MBean using the name
* "hadoop:service=DataNode,name=FSDatasetState-<storageid>"
* We use storage id for MBean name since a minicluster within a single
* Java VM may have multiple Simulated Datanodes.
*/
void registerMBean(final String storageId) {
// We wrap to bypass standard mbean naming convetion.
// This wraping can be removed in java 6 as it is more flexible in
// package naming for mbeans and their impl.
StandardMBean bean;
try {
bean = new StandardMBean(this,FSDatasetMBean.class);
mbeanName = MBeanUtil.registerMBean("DataNode",
"FSDatasetState-" + storageId, bean);
} catch (NotCompliantMBeanException e) {
e.printStackTrace();
}
DataNode.LOG.info("Registered FSDatasetStatusMBean");
}
public void shutdown() {
if (mbeanName != null)
MBeanUtil.unregisterMBean(mbeanName);
}
public String getStorageInfo() {
return "Simulated FSDataset-" + storageId;
}
}