From 84314d99e5aab13d2b011d2dd35de9314248192e Mon Sep 17 00:00:00 2001
From: Eli Collins <eli@apache.org>
Date: Tue, 7 Aug 2012 20:23:11 +0000
Subject: [PATCH] HDFS-3754. BlockSender doesn't shutdown ReadaheadPool
 threads. Contributed by Eli Collins

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1370496 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt               | 2 ++
 .../apache/hadoop/hdfs/server/datanode/BlockSender.java   | 8 ++------
 .../org/apache/hadoop/hdfs/server/datanode/DataNode.java  | 6 ++++++
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index bc27db3aea1..6ab29d18a76 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -410,6 +410,8 @@ Release 2.0.1-alpha - UNRELEASED
 
     HDFS-3579. libhdfs: fix exception handling. (Colin Patrick McCabe via atm)
 
+    HDFS-3754. BlockSender doesn't shutdown ReadaheadPool threads. (eli)
+
   BREAKDOWN OF HDFS-3042 SUBTASKS
 
     HDFS-2185. HDFS portion of ZK-based FailoverController (todd)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockSender.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockSender.java
index 133a550bd9d..d8cba720037 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockSender.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockSender.java
@@ -20,7 +20,6 @@ package org.apache.hadoop.hdfs.server.datanode;
 import java.io.BufferedInputStream;
 import java.io.DataInputStream;
 import java.io.DataOutputStream;
-import java.io.EOFException;
 import java.io.FileDescriptor;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
@@ -38,7 +37,6 @@ import org.apache.hadoop.fs.ChecksumException;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.datatransfer.PacketHeader;
-import org.apache.hadoop.hdfs.server.common.Util;
 import org.apache.hadoop.hdfs.util.DataTransferThrottler;
 import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.io.LongWritable;
@@ -163,8 +161,6 @@ class BlockSender implements java.io.Closeable {
    */
   private static final long LONG_READ_THRESHOLD_BYTES = 256 * 1024;
   
-  private static ReadaheadPool readaheadPool =
-    ReadaheadPool.getInstance();
 
   /**
    * Constructor
@@ -691,8 +687,8 @@ class BlockSender implements java.io.Closeable {
     }
 
     // Perform readahead if necessary
-    if (readaheadLength > 0 && readaheadPool != null) {
-      curReadahead = readaheadPool.readaheadStream(
+    if (readaheadLength > 0 && datanode.readaheadPool != null) {
+      curReadahead = datanode.readaheadPool.readaheadStream(
           clientTraceFmt, blockInFd,
           offset, readaheadLength, Long.MAX_VALUE,
           curReadahead);
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
index 0ebde007542..fd226e854f2 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
@@ -146,6 +146,7 @@ import org.apache.hadoop.hdfs.web.WebHdfsFileSystem;
 import org.apache.hadoop.hdfs.web.resources.Param;
 import org.apache.hadoop.http.HttpServer;
 import org.apache.hadoop.io.IOUtils;
+import org.apache.hadoop.io.ReadaheadPool;
 import org.apache.hadoop.ipc.ProtobufRpcEngine;
 import org.apache.hadoop.ipc.RPC;
 import org.apache.hadoop.ipc.RemoteException;
@@ -278,6 +279,7 @@ public class DataNode extends Configured
   private Configuration conf;
 
   private final String userWithLocalPathAccess;
+  ReadaheadPool readaheadPool;
 
   /**
    * Create the DataNode given a configuration and an array of dataDirs.
@@ -673,6 +675,10 @@ public class DataNode extends Configured
 
     blockPoolManager = new BlockPoolManager(this);
     blockPoolManager.refreshNamenodes(conf);
+
+    // Create the ReadaheadPool from the DataNode context so we can
+    // exit without having to explicitly shutdown its thread pool.
+    readaheadPool = ReadaheadPool.getInstance();
   }
   
   /**