HDFS-3222. DFSInputStream#openInfo should not silently get the length as 0 when locations length is zero for last partial block. Contributed by Uma Maheswara Rao G.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1331061 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Uma Maheswara Rao G 2012-04-26 20:18:01 +00:00
parent 1c0231cc74
commit d28b982428
2 changed files with 133 additions and 4 deletions

View File

@ -118,6 +118,39 @@ void addToDeadNodes(DatanodeInfo dnInfo) {
* Grab the open-file info from namenode
*/
synchronized void openInfo() throws IOException, UnresolvedLinkException {
lastBlockBeingWrittenLength = fetchLocatedBlocksAndGetLastBlockLength();
int retriesForLastBlockLength = 3;
while (retriesForLastBlockLength > 0) {
// Getting last block length as -1 is a special case. When cluster
// restarts, DNs may not report immediately. At this time partial block
// locations will not be available with NN for getting the length. Lets
// retry for 3 times to get the length.
if (lastBlockBeingWrittenLength == -1) {
DFSClient.LOG.warn("Last block locations not available. "
+ "Datanodes might not have reported blocks completely."
+ " Will retry for " + retriesForLastBlockLength + " times");
waitFor(4000);
lastBlockBeingWrittenLength = fetchLocatedBlocksAndGetLastBlockLength();
} else {
break;
}
retriesForLastBlockLength--;
}
if (retriesForLastBlockLength == 0) {
throw new IOException("Could not obtain the last block locations.");
}
}
private void waitFor(int waitTime) throws IOException {
try {
Thread.sleep(waitTime);
} catch (InterruptedException e) {
throw new IOException(
"Interrupted while getting the last block length.");
}
}
private long fetchLocatedBlocksAndGetLastBlockLength() throws IOException {
LocatedBlocks newInfo = DFSClient.callGetBlockLocations(dfsClient.namenode, src, 0, prefetchSize);
if (DFSClient.LOG.isDebugEnabled()) {
DFSClient.LOG.debug("newInfo = " + newInfo);
@ -136,10 +169,13 @@ synchronized void openInfo() throws IOException, UnresolvedLinkException {
}
}
locatedBlocks = newInfo;
lastBlockBeingWrittenLength = 0;
long lastBlockBeingWrittenLength = 0;
if (!locatedBlocks.isLastBlockComplete()) {
final LocatedBlock last = locatedBlocks.getLastLocatedBlock();
if (last != null) {
if (last.getLocations().length == 0) {
return -1;
}
final long len = readBlockLength(last);
last.getBlock().setNumBytes(len);
lastBlockBeingWrittenLength = len;
@ -147,13 +183,12 @@ synchronized void openInfo() throws IOException, UnresolvedLinkException {
}
currentNode = null;
return lastBlockBeingWrittenLength;
}
/** Read the block length from one of the datanodes. */
private long readBlockLength(LocatedBlock locatedblock) throws IOException {
if (locatedblock == null || locatedblock.getLocations().length == 0) {
return 0;
}
assert locatedblock != null : "LocatedBlock cannot be null";
int replicaNotFoundCount = locatedblock.getLocations().length;
for(DatanodeInfo datanode : locatedblock.getLocations()) {

View File

@ -0,0 +1,94 @@
/**
* 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 org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.client.HdfsDataInputStream;
import org.junit.Assert;
import org.junit.Test;
/** Test the fileLength on cluster restarts */
public class TestFileLengthOnClusterRestart {
/**
* Tests the fileLength when we sync the file and restart the cluster and
* Datanodes not report to Namenode yet.
*/
@Test(timeout = 60000)
public void testFileLengthWithHSyncAndClusterRestartWithOutDNsRegister()
throws Exception {
final Configuration conf = new HdfsConfiguration();
// create cluster
conf.setInt(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, 512);
final MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(2).build();
HdfsDataInputStream in = null;
try {
Path path = new Path(MiniDFSCluster.getBaseDirectory(), "test");
DistributedFileSystem dfs = (DistributedFileSystem) cluster
.getFileSystem();
FSDataOutputStream out = dfs.create(path);
int fileLength = 1030;
out.write(new byte[fileLength]);
out.hsync();
cluster.restartNameNode();
cluster.waitActive();
in = (HdfsDataInputStream) dfs.open(path, 1024);
// Verify the length when we just restart NN. DNs will register
// immediately.
Assert.assertEquals(fileLength, in.getVisibleLength());
cluster.shutdownDataNodes();
cluster.restartNameNode(false);
// This is just for ensuring NN started.
verifyNNIsInSafeMode(dfs);
try {
in = (HdfsDataInputStream) dfs.open(path);
Assert.fail("Expected IOException");
} catch (IOException e) {
Assert.assertEquals("Could not obtain the last block locations.", e
.getLocalizedMessage());
}
} finally {
if (null != in) {
in.close();
}
cluster.shutdown();
}
}
private void verifyNNIsInSafeMode(DistributedFileSystem dfs)
throws IOException {
while (true) {
try {
if (dfs.isInSafeMode()) {
return;
} else {
throw new IOException("Expected to be in SafeMode");
}
} catch (IOException e) {
// NN might not started completely Ignore
}
}
}
}