From 58d9479140e9d79af52c46b8fa7486bed6a1523b Mon Sep 17 00:00:00 2001
From: Chris Nauroth <cnauroth@apache.org>
Date: Mon, 7 Apr 2014 21:26:42 +0000
Subject: [PATCH] HDFS-6197. Merging change r1585586 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1585591 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt            |  3 +++
 .../hdfs/server/namenode/FileJournalManager.java       | 10 ++++++----
 .../org/apache/hadoop/hdfs/TestRollingUpgrade.java     |  1 +
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index e64c2293486..a8599bb2cdc 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -81,6 +81,9 @@ Release 2.4.1 - UNRELEASED
     HDFS-6189. Multiple HDFS tests fail on Windows attempting to use a test
     root path containing a colon.  (cnauroth via szetszwo) 
 
+    HDFS-6197. Rolling upgrade rollback on Windows can fail attempting to rename
+    edit log segment files to a destination that already exists. (cnauroth)
+
 Release 2.4.0 - 2014-04-07 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FileJournalManager.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FileJournalManager.java
index 63323ab2a0d..25440374652 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FileJournalManager.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FileJournalManager.java
@@ -512,10 +512,12 @@ public class FileJournalManager implements JournalManager {
     private void renameSelf(String newSuffix) throws IOException {
       File src = file;
       File dst = new File(src.getParent(), src.getName() + newSuffix);
-      boolean success = src.renameTo(dst);
-      if (!success) {
-        throw new IOException(
-          "Couldn't rename log " + src + " to " + dst);
+      // renameTo fails on Windows if the destination file already exists.
+      if (!src.renameTo(dst)) {
+        if (!dst.delete() || !src.renameTo(dst)) {
+          throw new IOException(
+            "Couldn't rename log " + src + " to " + dst);
+        }
       }
       file = dst;
     }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRollingUpgrade.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRollingUpgrade.java
index aed81793acc..326de7f788e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRollingUpgrade.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestRollingUpgrade.java
@@ -195,6 +195,7 @@ public class TestRollingUpgrade {
         Assert.assertEquals(info1, dfs.rollingUpgrade(RollingUpgradeAction.QUERY));
   
         dfs.mkdirs(bar);
+        cluster.shutdown();
       }
 
       // cluster2 takes over QJM