From c12e994eda0f7e0c34fb0c0ff208789586c7142c Mon Sep 17 00:00:00 2001
From: Eli Collins <eli@apache.org>
Date: Tue, 7 Aug 2012 20:17:59 +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/trunk@1370495 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 3730ba002f..6cf550d74e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -564,6 +564,8 @@ Branch-2 ( Unreleased changes )
 
     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 133a550bd9..d8cba72003 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 @@
 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.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 @@ private void manageOsCache() throws IOException {
     }
 
     // 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 6569fd19f6..dc6e3bc08c 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
@@ -144,6 +144,7 @@
 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;
@@ -275,6 +276,7 @@ public static InetSocketAddress createSocketAddr(String target) {
   private Configuration conf;
 
   private final String userWithLocalPathAccess;
+  ReadaheadPool readaheadPool;
 
   /**
    * Create the DataNode given a configuration and an array of dataDirs.
@@ -669,6 +671,10 @@ void startDataNode(Configuration conf,
 
     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();
   }
   
   /**