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HDFS-7678. Erasure coding: DFSInputStream with decode functionality (pread). Contributed by Zhe Zhang.

This commit is contained in:
Zhe Zhang 2015-05-11 21:10:23 -07:00 committed by Zhe Zhang
parent 6bacaa9a52
commit 8d3030f064
6 changed files with 768 additions and 72 deletions
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3
hadoop-hdfs-project/hadoop-hdfs/CHANGES-HDFS-EC-7285.txt
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@ -195,3 +195,6 @@
HDFS-8355. Erasure Coding: Refactor BlockInfo and BlockInfoUnderConstruction.
(Tsz Wo Nicholas Sze via jing9)
HDFS-7678. Erasure coding: DFSInputStream with decode functionality (pread).
(Zhe Zhang)

166
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSStripedInputStream.java
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@ -21,15 +21,27 @@ import com.google.common.base.Preconditions;
import org.apache.hadoop.fs.ChecksumException;
import org.apache.hadoop.fs.ReadOption;
import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.hdfs.protocol.*;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.protocol.LocatedBlock;
import org.apache.hadoop.hdfs.protocol.LocatedStripedBlock;
import org.apache.hadoop.hdfs.protocol.datatransfer.InvalidEncryptionKeyException;
import org.apache.hadoop.hdfs.util.StripedBlockUtil;
import org.apache.hadoop.io.ByteBufferPool;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.ReadPortion;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.planReadPortions;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.divideByteRangeIntoStripes;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.initDecodeInputs;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.decodeAndFillBuffer;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.getNextCompletedStripedRead;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.ReadPortion;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.AlignedStripe;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.StripingChunk;
import static org.apache.hadoop.hdfs.util.StripedBlockUtil.StripingChunkReadResult;
import org.apache.hadoop.io.erasurecode.ECSchema;
import org.apache.hadoop.net.NetUtils;
import org.apache.htrace.Span;
import org.apache.htrace.Trace;
@ -37,10 +49,12 @@ import org.apache.htrace.TraceScope;
import java.io.EOFException;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.util.EnumSet;
import java.util.Set;
import java.util.Collection;
import java.util.Map;
import java.util.HashMap;
import java.util.concurrent.CompletionService;
@ -51,7 +65,6 @@ import java.util.concurrent.CancellationException;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
/******************************************************************************
* DFSStripedInputStream reads from striped block groups, illustrated below:
*
@ -125,6 +138,7 @@ public class DFSStripedInputStream extends DFSInputStream {
private final short parityBlkNum;
/** the buffer for a complete stripe */
private ByteBuffer curStripeBuf;
private final ECSchema schema;
/**
* indicate the start/end offset of the current buffered stripe in the
* block group
@ -137,6 +151,7 @@ public class DFSStripedInputStream extends DFSInputStream {
super(dfsClient, src, verifyChecksum);
assert schema != null;
this.schema = schema;
cellSize = schema.getChunkSize();
dataBlkNum = (short) schema.getNumDataUnits();
parityBlkNum = (short) schema.getNumParityUnits();
@ -472,12 +487,10 @@ public class DFSStripedInputStream extends DFSInputStream {
*/
@Override
protected LocatedBlock getBlockAt(long blkStartOffset) throws IOException {
LocatedBlock lb = super.getBlockAt(blkStartOffset);
assert lb instanceof LocatedStripedBlock : "NameNode should return a " +
"LocatedStripedBlock for a striped file";
LocatedBlock lb = getBlockGroupAt(blkStartOffset);
int idx = (int) (((blkStartOffset - lb.getStartOffset()) / cellSize)
% dataBlkNum);
int idx = (int) ((blkStartOffset - lb.getStartOffset())
% (dataBlkNum + parityBlkNum));
// If indexing information is returned, iterate through the index array
// to find the entry for position idx in the group
LocatedStripedBlock lsb = (LocatedStripedBlock) lb;
@ -509,48 +522,121 @@ public class DFSStripedInputStream extends DFSInputStream {
long end, byte[] buf, int offset,
Map<ExtendedBlock, Set<DatanodeInfo>> corruptedBlockMap)
throws IOException {
Map<Future<Void>, Integer> futures = new HashMap<>();
CompletionService<Void> stripedReadsService =
new ExecutorCompletionService<>(dfsClient.getStripedReadsThreadPool());
int len = (int) (end - start + 1);
// Refresh the striped block group
LocatedStripedBlock blockGroup = getBlockGroupAt(blockStartOffset);
AlignedStripe[] stripes = divideByteRangeIntoStripes(schema, blockGroup,
start, end, buf, offset);
for (AlignedStripe stripe : stripes) {
fetchOneStripe(blockGroup, buf, stripe, corruptedBlockMap);
}
}
// Planning the portion of I/O for each shard
ReadPortion[] readPortions = planReadPortions(dataBlkNum, cellSize, start,
len, offset);
private void fetchOneStripe(LocatedStripedBlock blockGroup,
byte[] buf, AlignedStripe alignedStripe, Map<ExtendedBlock,
Set<DatanodeInfo>> corruptedBlockMap) throws IOException {
Map<Future<Void>, Integer> futures = new HashMap<>();
CompletionService<Void> service =
new ExecutorCompletionService<>(dfsClient.getStripedReadsThreadPool());
if (alignedStripe.getSpanInBlock() == 0) {
DFSClient.LOG.warn("Trying to read an empty stripe from" + blockGroup);
return;
}
// Parse group to get chosen DN location
LocatedBlock[] blks = StripedBlockUtil.
parseStripedBlockGroup(blockGroup, cellSize, dataBlkNum, parityBlkNum);
for (short i = 0; i < dataBlkNum; i++) {
ReadPortion rp = readPortions[i];
if (rp.getReadLength() <= 0) {
continue;
if (alignedStripe.chunks[i] != null
&& alignedStripe.chunks[i].state != StripingChunk.ALLZERO) {
fetchOneStripingChunk(futures, service, blks[i], alignedStripe, i,
corruptedBlockMap);
}
DatanodeInfo loc = blks[i].getLocations()[0];
StorageType type = blks[i].getStorageTypes()[0];
}
// Input buffers for potential decode operation, which remains null until
// first read failure
byte[][] decodeInputs = null;
while (!futures.isEmpty()) {
try {
StripingChunkReadResult r = getNextCompletedStripedRead(
service, futures, 0);
if (DFSClient.LOG.isDebugEnabled()) {
DFSClient.LOG.debug("Read task returned: " + r + ", for stripe " + alignedStripe);
}
StripingChunk returnedChunk = alignedStripe.chunks[r.index];
Preconditions.checkNotNull(returnedChunk);
Preconditions.checkState(returnedChunk.state == StripingChunk.PENDING);
if (r.state == StripingChunkReadResult.SUCCESSFUL) {
returnedChunk.state = StripingChunk.FETCHED;
alignedStripe.fetchedChunksNum++;
if (alignedStripe.fetchedChunksNum == dataBlkNum) {
clearFutures(futures.keySet());
break;
}
} else {
returnedChunk.state = StripingChunk.MISSING;
alignedStripe.missingChunksNum++;
if (alignedStripe.missingChunksNum > parityBlkNum) {
clearFutures(futures.keySet());
throw new IOException("Too many blocks are missing: " + alignedStripe);
}
// When seeing first missing block, initialize decode input buffers
if (decodeInputs == null) {
decodeInputs = initDecodeInputs(alignedStripe, dataBlkNum, parityBlkNum);
}
for (int i = 0; i < alignedStripe.chunks.length; i++) {
StripingChunk chunk = alignedStripe.chunks[i];
Preconditions.checkNotNull(chunk);
if (chunk.state == StripingChunk.REQUESTED && i <= dataBlkNum) {
fetchOneStripingChunk(futures, service, blks[i], alignedStripe, i,
corruptedBlockMap);
}
}
}
} catch (InterruptedException ie) {
String err = "Read request interrupted";
DFSClient.LOG.error(err);
clearFutures(futures.keySet());
// Don't decode if read interrupted
throw new InterruptedIOException(err);
}
}
if (alignedStripe.missingChunksNum > 0) {
decodeAndFillBuffer(decodeInputs, buf, alignedStripe,
dataBlkNum, parityBlkNum);
}
}
/**
* Schedule a single read request to an internal block
* @param block The internal block
* @param index Index of the internal block in the group
* @param corruptedBlockMap Map of corrupted blocks
*/
private void fetchOneStripingChunk(Map<Future<Void>, Integer> futures,
final CompletionService<Void> service, final LocatedBlock block,
final AlignedStripe alignedStripe, final int index,
Map<ExtendedBlock, Set<DatanodeInfo>> corruptedBlockMap) {
DatanodeInfo loc = block.getLocations()[0];
StorageType type = block.getStorageTypes()[0];
DNAddrPair dnAddr = new DNAddrPair(loc, NetUtils.createSocketAddr(
loc.getXferAddr(dfsClient.getConf().isConnectToDnViaHostname())),
type);
StripingChunk chunk = alignedStripe.chunks[index];
chunk.state = StripingChunk.PENDING;
Callable<Void> readCallable = getFromOneDataNode(dnAddr,
blks[i].getStartOffset(), rp.getStartOffsetInBlock(),
rp.getStartOffsetInBlock() + rp.getReadLength() - 1, buf,
rp.getOffsets(), rp.getLengths(), corruptedBlockMap, i);
Future<Void> getFromDNRequest = stripedReadsService.submit(readCallable);
DFSClient.LOG.debug("Submitting striped read request for " + blks[i]);
futures.put(getFromDNRequest, (int) i);
}
while (!futures.isEmpty()) {
try {
waitNextCompletion(stripedReadsService, futures);
} catch (InterruptedException ie) {
// Ignore and retry
}
block.getStartOffset(), alignedStripe.getOffsetInBlock(),
alignedStripe.getOffsetInBlock() + alignedStripe.getSpanInBlock() - 1, chunk.buf,
chunk.getOffsets(), chunk.getLengths(),
corruptedBlockMap, index);
Future<Void> getFromDNRequest = service.submit(readCallable);
if (DFSClient.LOG.isDebugEnabled()) {
DFSClient.LOG.debug("Submitting striped read request for " + index +
". Info of the block: " + block + ", offset in block is " +
alignedStripe.getOffsetInBlock() + ", end is " +
(alignedStripe.getOffsetInBlock() + alignedStripe.getSpanInBlock() - 1));
}
futures.put(getFromDNRequest, index);
}
private Callable<Void> getFromOneDataNode(final DNAddrPair datanode,
@ -609,4 +695,12 @@ public class DFSStripedInputStream extends DFSInputStream {
throw new UnsupportedOperationException(
"Not support enhanced byte buffer access.");
}
/** A variation to {@link DFSInputStream#cancelAll} */
private void clearFutures(Collection<Future<Void>> futures) {
for (Future<Void> future : futures) {
future.cancel(false);
}
futures.clear();
}
}

10
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/erasurecode/ErasureCodingWorker.java
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@ -67,7 +67,7 @@ import org.apache.hadoop.hdfs.server.datanode.CachingStrategy;
import org.apache.hadoop.hdfs.server.datanode.DataNode;
import org.apache.hadoop.hdfs.server.protocol.BlockECRecoveryCommand.BlockECRecoveryInfo;
import org.apache.hadoop.hdfs.util.StripedBlockUtil;
import org.apache.hadoop.hdfs.util.StripedBlockUtil.StripedReadResult;
import org.apache.hadoop.hdfs.util.StripedBlockUtil.StripingChunkReadResult;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.erasurecode.ECSchema;
import org.apache.hadoop.io.erasurecode.rawcoder.RSRawDecoder;
@ -462,10 +462,10 @@ public final class ErasureCodingWorker {
int nsuccess = 0;
while (!futures.isEmpty()) {
try {
StripedReadResult result =
StripingChunkReadResult result =
StripedBlockUtil.getNextCompletedStripedRead(
readService, futures, STRIPED_READ_THRESHOLD_MILLIS);
if (result.state == StripedReadResult.SUCCESSFUL) {
if (result.state == StripingChunkReadResult.SUCCESSFUL) {
success[nsuccess++] = result.index;
if (nsuccess >= dataBlkNum) {
// cancel remaining reads if we read successfully from minimum
@ -474,14 +474,14 @@ public final class ErasureCodingWorker {
futures.clear();
break;
}
} else if (result.state == StripedReadResult.FAILED) {
} else if (result.state == StripingChunkReadResult.FAILED) {
// If read failed for some source, we should not use it anymore
// and schedule read from a new source.
StripedReader failedReader = stripedReaders.get(result.index);
closeBlockReader(failedReader.blockReader);
failedReader.blockReader = null;
scheduleNewRead(used);
} else if (result.state == StripedReadResult.TIMEOUT) {
} else if (result.state == StripingChunkReadResult.TIMEOUT) {
// If timeout, we also schedule a new read.
scheduleNewRead(used);
}

513
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/util/StripedBlockUtil.java
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@ -22,16 +22,18 @@ import com.google.common.annotations.VisibleForTesting;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.hdfs.DFSClient;
import org.apache.hadoop.hdfs.DFSStripedOutputStream;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.protocol.LocatedBlock;
import org.apache.hadoop.hdfs.protocol.LocatedStripedBlock;
import com.google.common.base.Preconditions;
import org.apache.hadoop.io.erasurecode.ECSchema;
import org.apache.hadoop.io.erasurecode.rawcoder.RSRawDecoder;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.*;
import java.util.concurrent.CancellationException;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
@ -85,7 +87,7 @@ public class StripedBlockUtil {
new DatanodeInfo[]{bg.getLocations()[idxInReturnedLocs]},
new String[]{bg.getStorageIDs()[idxInReturnedLocs]},
new StorageType[]{bg.getStorageTypes()[idxInReturnedLocs]},
bg.getStartOffset() + idxInBlockGroup * cellSize, bg.isCorrupt(),
bg.getStartOffset() + idxInBlockGroup, bg.isCorrupt(),
null);
}
@ -238,33 +240,37 @@ public class StripedBlockUtil {
/**
* Get the next completed striped read task
*
* @return {@link StripedReadResult} indicating the status of the read task
* @return {@link StripingChunkReadResult} indicating the status of the read task
* succeeded, and the block index of the task. If the method times
* out without getting any completed read tasks, -1 is returned as
* block index.
* @throws InterruptedException
*/
public static StripedReadResult getNextCompletedStripedRead(
public static StripingChunkReadResult getNextCompletedStripedRead(
CompletionService<Void> readService, Map<Future<Void>, Integer> futures,
final long threshold) throws InterruptedException {
Preconditions.checkArgument(!futures.isEmpty());
Preconditions.checkArgument(threshold > 0);
Future<Void> future = null;
try {
if (threshold > 0) {
future = readService.poll(threshold, TimeUnit.MILLISECONDS);
} else {
future = readService.take();
}
if (future != null) {
future.get();
return new StripedReadResult(futures.remove(future),
StripedReadResult.SUCCESSFUL);
return new StripingChunkReadResult(futures.remove(future),
StripingChunkReadResult.SUCCESSFUL);
} else {
return new StripedReadResult(StripedReadResult.TIMEOUT);
return new StripingChunkReadResult(StripingChunkReadResult.TIMEOUT);
}
} catch (ExecutionException e) {
return new StripedReadResult(futures.remove(future),
StripedReadResult.FAILED);
DFSClient.LOG.error("ExecutionException " + e);
return new StripingChunkReadResult(futures.remove(future),
StripingChunkReadResult.FAILED);
} catch (CancellationException e) {
return new StripedReadResult(futures.remove(future),
StripedReadResult.CANCELLED);
return new StripingChunkReadResult(futures.remove(future),
StripingChunkReadResult.CANCELLED);
}
}
@ -291,26 +297,247 @@ public class StripedBlockUtil {
}
/**
* This class represents the portion of I/O associated with each block in the
* striped block group.
* Initialize the decoding input buffers based on the chunk states in an
* AlignedStripe
*/
public static class ReadPortion {
public static byte[][] initDecodeInputs(AlignedStripe alignedStripe,
int dataBlkNum, int parityBlkNum) {
byte[][] decodeInputs =
new byte[dataBlkNum + parityBlkNum][(int) alignedStripe.getSpanInBlock()];
for (int i = 0; i < alignedStripe.chunks.length; i++) {
StripingChunk chunk = alignedStripe.chunks[i];
if (chunk == null) {
alignedStripe.chunks[i] = new StripingChunk(decodeInputs[i]);
alignedStripe.chunks[i].offsetsInBuf.add(0);
alignedStripe.chunks[i].lengthsInBuf.add((int) alignedStripe.getSpanInBlock());
} else if (chunk.state == StripingChunk.FETCHED) {
int posInBuf = 0;
for (int j = 0; j < chunk.offsetsInBuf.size(); j++) {
System.arraycopy(chunk.buf, chunk.offsetsInBuf.get(j),
decodeInputs[i], posInBuf, chunk.lengthsInBuf.get(j));
posInBuf += chunk.lengthsInBuf.get(j);
}
} else if (chunk.state == StripingChunk.ALLZERO) {
Arrays.fill(decodeInputs[i], (byte)0);
}
}
return decodeInputs;
}
/**
* startOffsetInBlock
* |
* v
* |<-lengths[0]->|<- lengths[1] ->|<-lengths[2]->|
* Decode based on the given input buffers and schema
*/
public static void decodeAndFillBuffer(final byte[][] decodeInputs, byte[] buf,
AlignedStripe alignedStripe, int dataBlkNum, int parityBlkNum) {
int[] decodeIndices = new int[parityBlkNum];
int pos = 0;
for (int i = 0; i < alignedStripe.chunks.length; i++) {
if (alignedStripe.chunks[i].state != StripingChunk.FETCHED &&
alignedStripe.chunks[i].state != StripingChunk.ALLZERO) {
decodeIndices[pos++] = i;
}
}
byte[][] outputs = new byte[parityBlkNum][(int) alignedStripe.getSpanInBlock()];
RSRawDecoder rsRawDecoder = new RSRawDecoder();
rsRawDecoder.initialize(dataBlkNum, parityBlkNum, (int) alignedStripe.getSpanInBlock());
rsRawDecoder.decode(decodeInputs, decodeIndices, outputs);
for (int i = 0; i < dataBlkNum + parityBlkNum; i++) {
StripingChunk chunk = alignedStripe.chunks[i];
if (chunk.state == StripingChunk.MISSING) {
int srcPos = 0;
for (int j = 0; j < chunk.offsetsInBuf.size(); j++) {
//TODO: workaround (filling fixed bytes), to remove after HADOOP-11938
// System.arraycopy(outputs[i], srcPos, buf, chunk.offsetsInBuf.get(j),
// chunk.lengthsInBuf.get(j));
Arrays.fill(buf, chunk.offsetsInBuf.get(j),
chunk.offsetsInBuf.get(j) + chunk.lengthsInBuf.get(j), (byte)7);
srcPos += chunk.lengthsInBuf.get(j);
}
}
}
}
/**
* This method divides a requested byte range into an array of
* {@link AlignedStripe}
*
*
* At most 5 stripes will be generated from each logical range
* TODO: cleanup and get rid of planReadPortions
*/
public static AlignedStripe[] divideByteRangeIntoStripes (
ECSchema ecSchema, LocatedStripedBlock blockGroup, long start, long end,
byte[] buf, int offsetInBuf) {
// TODO: change ECSchema naming to use cell size instead of chunk size
// Step 0: analyze range and calculate basic parameters
int cellSize = ecSchema.getChunkSize();
int dataBlkNum = ecSchema.getNumDataUnits();
int len = (int) (end - start + 1);
int firstCellIdxInBG = (int) (start / cellSize);
int lastCellIdxInBG = (int) (end / cellSize);
int firstCellSize = Math.min(cellSize - (int) (start % cellSize), len);
long firstCellOffsetInBlk = start % cellSize;
int lastCellSize = lastCellIdxInBG == firstCellIdxInBG ?
firstCellSize : (int) (end % cellSize) + 1;
// Step 1: get the unmerged ranges on each internal block
// TODO: StripingCell should carry info on size and start offset (HDFS-8320)
VerticalRange[] ranges = getRangesForInternalBlocks(ecSchema,
firstCellIdxInBG, lastCellIdxInBG, firstCellSize, firstCellOffsetInBlk,
lastCellSize);
// Step 2: merge into at most 5 stripes
AlignedStripe[] stripes = mergeRangesForInternalBlocks(ecSchema, ranges);
// Step 3: calculate each chunk's position in destination buffer
calcualteChunkPositionsInBuf(ecSchema, blockGroup, buf, offsetInBuf,
firstCellIdxInBG, lastCellIdxInBG, firstCellSize, firstCellOffsetInBlk,
lastCellSize, stripes);
// Step 4: prepare ALLZERO blocks
prepareAllZeroChunks(blockGroup, buf, stripes, cellSize, dataBlkNum);
return stripes;
}
private static VerticalRange[] getRangesForInternalBlocks (ECSchema ecSchema,
int firstCellIdxInBG, int lastCellIdxInBG, int firstCellSize,
long firstCellOffsetInBlk, int lastCellSize) {
int cellSize = ecSchema.getChunkSize();
int dataBlkNum = ecSchema.getNumDataUnits();
StripingCell firstCell = new StripingCell(ecSchema, firstCellIdxInBG);
StripingCell lastCell = new StripingCell(ecSchema, lastCellIdxInBG);
VerticalRange ranges[] = new VerticalRange[dataBlkNum];
ranges[firstCell.idxInStripe] =
new VerticalRange(firstCellOffsetInBlk, firstCellSize);
for (int i = firstCellIdxInBG + 1; i < lastCellIdxInBG; i++) {
// iterate through all cells and update the list of StripeRanges
StripingCell cell = new StripingCell(ecSchema, i);
if (ranges[cell.idxInStripe] == null) {
ranges[cell.idxInStripe] = new VerticalRange(
cell.idxInInternalBlk * cellSize, cellSize);
} else {
ranges[cell.idxInStripe].spanInBlock += cellSize;
}
}
if (ranges[lastCell.idxInStripe] == null) {
ranges[lastCell.idxInStripe] = new VerticalRange(
lastCell.idxInInternalBlk * cellSize, lastCellSize);
} else if (lastCell.idxInBlkGroup != firstCell.idxInBlkGroup) {
ranges[lastCell.idxInStripe].spanInBlock += lastCellSize;
}
return ranges;
}
private static AlignedStripe[] mergeRangesForInternalBlocks(ECSchema ecSchema,
VerticalRange[] ranges) {
int dataBlkNum = ecSchema.getNumDataUnits();
int parityBlkNum = ecSchema.getNumParityUnits();
List<AlignedStripe> stripes = new ArrayList<>();
SortedSet<Long> stripePoints = new TreeSet<>();
for (VerticalRange r : ranges) {
if (r != null) {
stripePoints.add(r.offsetInBlock);
stripePoints.add(r.offsetInBlock + r.spanInBlock);
}
}
long prev = -1;
for (long point : stripePoints) {
if (prev >= 0) {
stripes.add(new AlignedStripe(prev, point - prev,
dataBlkNum + parityBlkNum));
}
prev = point;
}
return stripes.toArray(new AlignedStripe[stripes.size()]);
}
private static void calcualteChunkPositionsInBuf(ECSchema ecSchema,
LocatedStripedBlock blockGroup, byte[] buf, int offsetInBuf,
int firstCellIdxInBG, int lastCellIdxInBG, int firstCellSize,
long firstCellOffsetInBlk, int lastCellSize, AlignedStripe[] stripes) {
int cellSize = ecSchema.getChunkSize();
int dataBlkNum = ecSchema.getNumDataUnits();
// Step 3: calculate each chunk's position in destination buffer
/**
* | <--------------- AlignedStripe --------------->|
*
* |<- length_0 ->|<-- length_1 -->|<- length_2 ->|
* +------------------+------------------+----------------+
* | cell_0 | cell_3 | cell_6 | <- blk_0
* | cell_0_0_0 | cell_3_1_0 | cell_6_2_0 | <- blk_0
* +------------------+------------------+----------------+
* _/ \_______________________
* | |
* v offsetsInBuf[0] v offsetsInBuf[1]
* +------------------------------------------------------+
* | cell_0 | cell_1 and cell_2 |cell_3 ...| <- buf
* v offset_0 v offset_1
* +----------------------------------------------------------+
* | cell_0_0_0 | cell_1_0_1 and cell_2_0_2 |cell_3_1_0 ...| <- buf
* | (partial) | (from blk_1 and blk_2) | |
* +------------------------------------------------------+
* +----------------------------------------------------------+
*
* Cell indexing convention defined in {@link StripingCell}
*/
int done = 0;
for (int i = firstCellIdxInBG; i <= lastCellIdxInBG; i++) {
StripingCell cell = new StripingCell(ecSchema, i);
long cellStart = i == firstCellIdxInBG ?
firstCellOffsetInBlk : cell.idxInInternalBlk * cellSize;
int cellLen;
if (i == firstCellIdxInBG) {
cellLen = firstCellSize;
} else if (i == lastCellIdxInBG) {
cellLen = lastCellSize;
} else {
cellLen = cellSize;
}
long cellEnd = cellStart + cellLen - 1;
for (AlignedStripe s : stripes) {
long stripeEnd = s.getOffsetInBlock() + s.getSpanInBlock() - 1;
long overlapStart = Math.max(cellStart, s.getOffsetInBlock());
long overlapEnd = Math.min(cellEnd, stripeEnd);
int overLapLen = (int) (overlapEnd - overlapStart + 1);
if (overLapLen <= 0) {
continue;
}
if (s.chunks[cell.idxInStripe] == null) {
s.chunks[cell.idxInStripe] = new StripingChunk(buf);
}
s.chunks[cell.idxInStripe].offsetsInBuf.
add((int)(offsetInBuf + done + overlapStart - cellStart));
s.chunks[cell.idxInStripe].lengthsInBuf.add(overLapLen);
}
done += cellLen;
}
}
private static void prepareAllZeroChunks(LocatedStripedBlock blockGroup,
byte[] buf, AlignedStripe[] stripes, int cellSize, int dataBlkNum) {
for (AlignedStripe s : stripes) {
for (int i = 0; i < dataBlkNum; i++) {
long internalBlkLen = getInternalBlockLength(blockGroup.getBlockSize(),
cellSize, dataBlkNum, i);
if (internalBlkLen <= s.getOffsetInBlock()) {
Preconditions.checkState(s.chunks[i] == null);
s.chunks[i] = new StripingChunk(buf);
s.chunks[i].state = StripingChunk.ALLZERO;
}
}
}
}
/**
* This class represents the portion of I/O associated with each block in the
* striped block group.
* TODO: consolidate ReadPortion with AlignedStripe
*/
public static class ReadPortion {
private long startOffsetInBlock = 0;
private int readLength = 0;
public final List<Integer> offsetsInBuf = new ArrayList<>();
@ -349,12 +576,235 @@ public class StripedBlockUtil {
}
}
/**
* The unit of encoding used in {@link DFSStripedOutputStream}
* | <------- Striped Block Group -------> |
* blk_0 blk_1 blk_2
* | | |
* v v v
* +----------+ +----------+ +----------+
* |cell_0_0_0| |cell_1_0_1| |cell_2_0_2|
* +----------+ +----------+ +----------+
* |cell_3_1_0| |cell_4_1_1| |cell_5_1_2| <- {@link idxInBlkGroup} = 5
* +----------+ +----------+ +----------+ {@link idxInInternalBlk} = 1
* {@link idxInStripe} = 2
* A StripingCell is a special instance of {@link StripingChunk} whose offset
* and size align with the cell used when writing data.
* TODO: consider parity cells
*/
public static class StripingCell {
public final ECSchema schema;
/** Logical order in a block group, used when doing I/O to a block group */
public final int idxInBlkGroup;
public final int idxInInternalBlk;
public final int idxInStripe;
public StripingCell(ECSchema ecSchema, int idxInBlkGroup) {
this.schema = ecSchema;
this.idxInBlkGroup = idxInBlkGroup;
this.idxInInternalBlk = idxInBlkGroup / ecSchema.getNumDataUnits();
this.idxInStripe = idxInBlkGroup -
this.idxInInternalBlk * ecSchema.getNumDataUnits();
}
public StripingCell(ECSchema ecSchema, int idxInInternalBlk,
int idxInStripe) {
this.schema = ecSchema;
this.idxInInternalBlk = idxInInternalBlk;
this.idxInStripe = idxInStripe;
this.idxInBlkGroup =
idxInInternalBlk * ecSchema.getNumDataUnits() + idxInStripe;
}
}
/**
* Given a requested byte range on a striped block group, an AlignedStripe
* represents a {@link VerticalRange} that is aligned with both the byte range
* and boundaries of all internal blocks. As illustrated in the diagram, any
* given byte range on a block group leads to 1~5 AlignedStripe's.
*
* |<-------- Striped Block Group -------->|
* blk_0 blk_1 blk_2 blk_3 blk_4
* +----+ | +----+ +----+
* |full| | | | | | <- AlignedStripe0:
* +----+ |~~~~| | |~~~~| |~~~~| 1st cell is partial
* |part| | | | | | | | <- AlignedStripe1: byte range
* +----+ +----+ +----+ | |~~~~| |~~~~| doesn't start at 1st block
* |full| |full| |full| | | | | |
* |cell| |cell| |cell| | | | | | <- AlignedStripe2 (full stripe)
* | | | | | | | | | | |
* +----+ +----+ +----+ | |~~~~| |~~~~|
* |full| |part| | | | | | <- AlignedStripe3: byte range
* |~~~~| +----+ | |~~~~| |~~~~| doesn't end at last block
* | | | | | | | <- AlignedStripe4:
* +----+ | +----+ +----+ last cell is partial
* |
* <---- data blocks ----> | <--- parity --->
*
* An AlignedStripe is the basic unit of reading from a striped block group,
* because within the AlignedStripe, all internal blocks can be processed in
* a uniform manner.
*
* The coverage of an AlignedStripe on an internal block is represented as a
* {@link StripingChunk}.
* To simplify the logic of reading a logical byte range from a block group,
* a StripingChunk is either completely in the requested byte range or
* completely outside the requested byte range.
*/
public static class AlignedStripe {
public VerticalRange range;
/** status of each chunk in the stripe */
public final StripingChunk[] chunks;
public int fetchedChunksNum = 0;
public int missingChunksNum = 0;
public AlignedStripe(long offsetInBlock, long length, int width) {
Preconditions.checkArgument(offsetInBlock >= 0 && length >= 0);
this.range = new VerticalRange(offsetInBlock, length);
this.chunks = new StripingChunk[width];
}
public AlignedStripe(VerticalRange range, int width) {
this.range = range;
this.chunks = new StripingChunk[width];
}
public boolean include(long pos) {
return range.include(pos);
}
public long getOffsetInBlock() {
return range.offsetInBlock;
}
public long getSpanInBlock() {
return range.spanInBlock;
}
@Override
public String toString() {
return "Offset=" + range.offsetInBlock + ", length=" + range.spanInBlock +
", fetchedChunksNum=" + fetchedChunksNum +
", missingChunksNum=" + missingChunksNum;
}
}
/**
* A simple utility class representing an arbitrary vertical inclusive range
* starting at {@link offsetInBlock} and lasting for {@link length} bytes in
* an internal block. Note that VerticalRange doesn't necessarily align with
* {@link StripingCell}.
*
* |<- Striped Block Group ->|
* blk_0
* |
* v
* +-----+
* |~~~~~| <-- {@link offsetInBlock}
* | | ^
* | | |
* | | | {@link spanInBlock}
* | | v
* |~~~~~| ---
* | |
* +-----+
*/
public static class VerticalRange {
/** start offset in the block group (inclusive) */
public long offsetInBlock;
/** length of the stripe range */
public long spanInBlock;
public VerticalRange(long offsetInBlock, long length) {
Preconditions.checkArgument(offsetInBlock >= 0 && length >= 0);
this.offsetInBlock = offsetInBlock;
this.spanInBlock = length;
}
/** whether a position is in the range */
public boolean include(long pos) {
return pos >= offsetInBlock && pos < offsetInBlock + spanInBlock;
}
}
/**
* Indicates the coverage of an {@link AlignedStripe} on an internal block,
* and the state of the chunk in the context of the read request.
*
* |<---------------- Striped Block Group --------------->|
* blk_0 blk_1 blk_2 blk_3 blk_4
* +---------+ | +----+ +----+
* null null |REQUESTED| | |null| |null| <- AlignedStripe0
* +---------+ |---------| | |----| |----|
* null |REQUESTED| |REQUESTED| | |null| |null| <- AlignedStripe1
* +---------+ +---------+ +---------+ | +----+ +----+
* |REQUESTED| |REQUESTED| ALLZERO | |null| |null| <- AlignedStripe2
* +---------+ +---------+ | +----+ +----+
* <----------- data blocks ------------> | <--- parity --->
*
* The class also carries {@link buf}, {@link offsetsInBuf}, and
* {@link lengthsInBuf} to define how read task for this chunk should deliver
* the returned data.
*/
public static class StripingChunk {
/** Chunk has been successfully fetched */
public static final int FETCHED = 0x01;
/** Chunk has encountered failed when being fetched */
public static final int MISSING = 0x02;
/** Chunk being fetched (fetching task is in-flight) */
public static final int PENDING = 0x04;
/**
* Chunk is requested either by application or for decoding, need to
* schedule read task
*/
public static final int REQUESTED = 0X08;
/**
* Internal block is short and has no overlap with chunk. Chunk considered
* all-zero bytes in codec calculations.
*/
public static final int ALLZERO = 0X0f;
/**
* If a chunk is completely in requested range, the state transition is:
* REQUESTED (when AlignedStripe created) -> PENDING -> {FETCHED | MISSING}
* If a chunk is completely outside requested range (including parity
* chunks), state transition is:
* null (AlignedStripe created) -> REQUESTED (upon failure) -> PENDING ...
*/
public int state = REQUESTED;
public byte[] buf;
public List<Integer> offsetsInBuf;
public List<Integer> lengthsInBuf;
public StripingChunk(byte[] buf) {
this.buf = buf;
this.offsetsInBuf = new ArrayList<>();
this.lengthsInBuf = new ArrayList<>();
}
public int[] getOffsets() {
int[] offsets = new int[offsetsInBuf.size()];
for (int i = 0; i < offsets.length; i++) {
offsets[i] = offsetsInBuf.get(i);
}
return offsets;
}
public int[] getLengths() {
int[] lens = new int[this.lengthsInBuf.size()];
for (int i = 0; i < lens.length; i++) {
lens[i] = this.lengthsInBuf.get(i);
}
return lens;
}
}
/**
* This class represents result from a striped read request.
* If the task was successful or the internal computation failed,
* an index is also returned.
*/
public static class StripedReadResult {
public static class StripingChunkReadResult {
public static final int SUCCESSFUL = 0x01;
public static final int FAILED = 0x02;
public static final int TIMEOUT = 0x04;
@ -363,18 +813,23 @@ public class StripedBlockUtil {
public final int index;
public final int state;
public StripedReadResult(int state) {
public StripingChunkReadResult(int state) {
Preconditions.checkArgument(state == TIMEOUT,
"Only timeout result should return negative index.");
this.index = -1;
this.state = state;
}
public StripedReadResult(int index, int state) {
public StripingChunkReadResult(int index, int state) {
Preconditions.checkArgument(state != TIMEOUT,
"Timeout result should return negative index.");
this.index = index;
this.state = state;
}
@Override
public String toString() {
return "(index=" + index + ", state =" + state + ")";
}
}
}

97
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSStripedInputStream.java
View File

@ -36,6 +36,7 @@ import org.apache.hadoop.hdfs.server.datanode.SimulatedFSDataset;
import org.apache.hadoop.hdfs.server.namenode.ErasureCodingSchemaManager;
import org.apache.hadoop.hdfs.util.StripedBlockUtil;
import org.apache.hadoop.io.erasurecode.ECSchema;
import org.apache.hadoop.io.erasurecode.rawcoder.RSRawDecoder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
@ -133,8 +134,102 @@ public class TestDFSStripedInputStream {
byte[] readBuffer = new byte[readSize];
int ret = in.read(0, readBuffer, 0, readSize);
byte[] expected = new byte[readSize];
/** A variation of {@link DFSTestUtil#fillExpectedBuf} for striped blocks */
for (int i = 0; i < NUM_STRIPE_PER_BLOCK; i++) {
for (int j = 0; j < DATA_BLK_NUM; j++) {
for (int k = 0; k < CELLSIZE; k++) {
int posInBlk = i * CELLSIZE + k;
int posInFile = i * CELLSIZE * DATA_BLK_NUM + j * CELLSIZE + k;
expected[posInFile] = SimulatedFSDataset.simulatedByte(
new Block(bg.getBlock().getBlockId() + j), posInBlk);
}
}
}
assertEquals(readSize, ret);
// TODO: verify read results with patterned data from HDFS-8117
assertArrayEquals(expected, readBuffer);
}
@Test
public void testPreadWithDNFailure() throws Exception {
final int numBlocks = 4;
final int failedDNIdx = 2;
DFSTestUtil.createStripedFile(cluster, filePath, null, numBlocks,
NUM_STRIPE_PER_BLOCK, false);
LocatedBlocks lbs = fs.getClient().namenode.getBlockLocations(
filePath.toString(), 0, BLOCK_GROUP_SIZE);
assert lbs.get(0) instanceof LocatedStripedBlock;
LocatedStripedBlock bg = (LocatedStripedBlock)(lbs.get(0));
for (int i = 0; i < DATA_BLK_NUM + PARITY_BLK_NUM; i++) {
Block blk = new Block(bg.getBlock().getBlockId() + i,
NUM_STRIPE_PER_BLOCK * CELLSIZE,
bg.getBlock().getGenerationStamp());
blk.setGenerationStamp(bg.getBlock().getGenerationStamp());
cluster.injectBlocks(i, Arrays.asList(blk),
bg.getBlock().getBlockPoolId());
}
DFSStripedInputStream in =
new DFSStripedInputStream(fs.getClient(), filePath.toString(), false,
ErasureCodingSchemaManager.getSystemDefaultSchema());
int readSize = BLOCK_GROUP_SIZE;
byte[] readBuffer = new byte[readSize];
byte[] expected = new byte[readSize];
cluster.stopDataNode(failedDNIdx);
/** A variation of {@link DFSTestUtil#fillExpectedBuf} for striped blocks */
for (int i = 0; i < NUM_STRIPE_PER_BLOCK; i++) {
for (int j = 0; j < DATA_BLK_NUM; j++) {
for (int k = 0; k < CELLSIZE; k++) {
int posInBlk = i * CELLSIZE + k;
int posInFile = i * CELLSIZE * DATA_BLK_NUM + j * CELLSIZE + k;
expected[posInFile] = SimulatedFSDataset.simulatedByte(
new Block(bg.getBlock().getBlockId() + j), posInBlk);
}
}
}
// Update the expected content for decoded data
for (int i = 0; i < NUM_STRIPE_PER_BLOCK; i++) {
byte[][] decodeInputs = new byte[DATA_BLK_NUM + PARITY_BLK_NUM][CELLSIZE];
int[] missingBlkIdx = new int[]{failedDNIdx, DATA_BLK_NUM+1, DATA_BLK_NUM+2};
byte[][] decodeOutputs = new byte[PARITY_BLK_NUM][CELLSIZE];
for (int j = 0; j < DATA_BLK_NUM; j++) {
int posInBuf = i * CELLSIZE * DATA_BLK_NUM + j * CELLSIZE;
if (j != failedDNIdx) {
System.arraycopy(expected, posInBuf, decodeInputs[j], 0, CELLSIZE);
}
}
for (int k = 0; k < CELLSIZE; k++) {
int posInBlk = i * CELLSIZE + k;
decodeInputs[DATA_BLK_NUM][k] = SimulatedFSDataset.simulatedByte(
new Block(bg.getBlock().getBlockId() + DATA_BLK_NUM), posInBlk);
}
// RSRawDecoder rsRawDecoder = new RSRawDecoder();
// rsRawDecoder.initialize(DATA_BLK_NUM, PARITY_BLK_NUM, CELLSIZE);
// rsRawDecoder.decode(decodeInputs, missingBlkIdx, decodeOutputs);
int posInBuf = i * CELLSIZE * DATA_BLK_NUM + failedDNIdx * CELLSIZE;
// System.arraycopy(decodeOutputs[0], 0, expected, posInBuf, CELLSIZE);
//TODO: workaround (filling fixed bytes), to remove after HADOOP-11938
Arrays.fill(expected, posInBuf, posInBuf + CELLSIZE, (byte)7);
}
int delta = 10;
int done = 0;
// read a small delta, shouldn't trigger decode
// |cell_0 |
// |10 |
done += in.read(0, readBuffer, 0, delta);
assertEquals(delta, done);
// both head and trail cells are partial
// |c_0 |c_1 |c_2 |c_3 |c_4 |c_5 |
// |256K - 10|missing|256K|256K|256K - 10|not in range|
done += in.read(delta, readBuffer, delta,
CELLSIZE * (DATA_BLK_NUM - 1) - 2 * delta);
assertEquals(CELLSIZE * (DATA_BLK_NUM - 1) - delta, done);
// read the rest
done += in.read(done, readBuffer, done, readSize - done);
assertEquals(readSize, done);
assertArrayEquals(expected, readBuffer);
}
@Test

49
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestWriteReadStripedFile.java
View File

@ -18,10 +18,13 @@
package org.apache.hadoop.hdfs;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.server.datanode.DataNode;
import org.apache.hadoop.io.erasurecode.rawcoder.RSRawDecoder;
import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.BeforeClass;
@ -321,4 +324,50 @@ public class TestWriteReadStripedFile {
Assert.assertArrayEquals(bytes, result.array());
}
}
@Test
public void testWritePreadWithDNFailure() throws IOException {
final int failedDNIdx = 2;
final int length = cellSize * (dataBlocks + 2);
Path testPath = new Path("/foo");
final byte[] bytes = generateBytes(length);
DFSTestUtil.writeFile(fs, testPath, new String(bytes));
// shut down the DN that holds the last internal data block
BlockLocation[] locs = fs.getFileBlockLocations(testPath, cellSize * 5,
cellSize);
String name = (locs[0].getNames())[failedDNIdx];
for (DataNode dn : cluster.getDataNodes()) {
int port = dn.getXferPort();
if (name.contains(Integer.toString(port))) {
dn.shutdown();
break;
}
}
// pread
int startOffsetInFile = cellSize * 5;
try (FSDataInputStream fsdis = fs.open(testPath)) {
byte[] buf = new byte[length];
int readLen = fsdis.read(startOffsetInFile, buf, 0, buf.length);
Assert.assertEquals("The length of file should be the same to write size",
length - startOffsetInFile, readLen);
RSRawDecoder rsRawDecoder = new RSRawDecoder();
rsRawDecoder.initialize(dataBlocks, parityBlocks, 1);
byte[] expected = new byte[readLen];
for (int i = startOffsetInFile; i < length; i++) {
//TODO: workaround (filling fixed bytes), to remove after HADOOP-11938
if ((i / cellSize) % dataBlocks == failedDNIdx) {
expected[i - startOffsetInFile] = (byte)7;
} else {
expected[i - startOffsetInFile] = getByte(i);
}
}
for (int i = startOffsetInFile; i < length; i++) {
Assert.assertEquals("Byte at " + i + " should be the same",
expected[i - startOffsetInFile], buf[i - startOffsetInFile]);
}
}
}
}