From 7fe6ab7f910491157cb7462563099e882b256bca Mon Sep 17 00:00:00 2001
From: Colin McCabe <cmccabe@apache.org>
Date: Tue, 15 Jul 2014 18:17:13 +0000
Subject: [PATCH] HDFS-5809. BlockPoolSliceScanner and high speed hdfs
 appending make datanode to drop into infinite loop (cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1610790 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  3 +++
 .../datanode/BlockPoolSliceScanner.java       | 25 ++++++++-----------
 .../server/datanode/DataNodeTestUtils.java    |  3 ++-
 3 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 155cc706a0d..37360ab3fb2 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -306,6 +306,9 @@ Release 2.6.0 - UNRELEASED
     HDFS-6678. MiniDFSCluster may still be partially running after initialization
     fails. (cnauroth)
 
+    HDFS-5809. BlockPoolSliceScanner and high speed hdfs appending make
+    datanode to drop into infinite loop (cmccabe)
+
 Release 2.5.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolSliceScanner.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolSliceScanner.java
index 5310c3df522..1039b4fe922 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolSliceScanner.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolSliceScanner.java
@@ -310,18 +310,11 @@ class BlockPoolSliceScanner {
     }
   }
   
-  private synchronized void updateScanStatus(Block block, 
+  private synchronized void updateScanStatus(BlockScanInfo info,
                                              ScanType type,
                                              boolean scanOk) {
-    BlockScanInfo info = blockMap.get(block);
-    
-    if ( info != null ) {
-      delBlockInfo(info);
-    } else {
-      // It might already be removed. Thats ok, it will be caught next time.
-      info = new BlockScanInfo(block);
-    }
-    
+    delBlockInfo(info);
+
     long now = Time.monotonicNow();
     info.lastScanType = type;
     info.lastScanTime = now;
@@ -334,8 +327,8 @@ class BlockPoolSliceScanner {
     }
     
     if (verificationLog != null) {
-      verificationLog.append(now, block.getGenerationStamp(),
-          block.getBlockId());
+      verificationLog.append(now, info.getGenerationStamp(),
+          info.getBlockId());
     }
   }
   
@@ -434,11 +427,13 @@ class BlockPoolSliceScanner {
           totalTransientErrors++;
         }
         
-        updateScanStatus(block.getLocalBlock(), ScanType.VERIFICATION_SCAN, true);
+        updateScanStatus((BlockScanInfo)block.getLocalBlock(),
+            ScanType.VERIFICATION_SCAN, true);
 
         return;
       } catch (IOException e) {
-        updateScanStatus(block.getLocalBlock(), ScanType.VERIFICATION_SCAN, false);
+        updateScanStatus((BlockScanInfo)block.getLocalBlock(),
+            ScanType.VERIFICATION_SCAN, false);
 
         // If the block does not exists anymore, then its not an error
         if (!dataset.contains(block)) {
@@ -497,7 +492,7 @@ class BlockPoolSliceScanner {
   
   // Picks one block and verifies it
   private void verifyFirstBlock() {
-    Block block = null;
+    BlockScanInfo block = null;
     synchronized (this) {
       if (!blockInfoSet.isEmpty()) {
         block = blockInfoSet.first();
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java
index 2cf8f6d51b2..f50afd46325 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java
@@ -116,7 +116,8 @@ public class DataNodeTestUtils {
   
   public static void runBlockScannerForBlock(DataNode dn, ExtendedBlock b) {
     BlockPoolSliceScanner bpScanner = getBlockPoolScanner(dn, b);
-    bpScanner.verifyBlock(b);
+    bpScanner.verifyBlock(new ExtendedBlock(b.getBlockPoolId(),
+        new BlockPoolSliceScanner.BlockScanInfo(b.getLocalBlock())));
   }
 
   private static BlockPoolSliceScanner getBlockPoolScanner(DataNode dn,