[42/43] hadoop git commit: HDFS-8480. Fix performance and timeout issues in HDFS-7929 by using hard-links to preserve old edit logs, instead of copying them. (Zhe Zhang via Colin P. McCabe)

[sjlee]

HDFS-8480. Fix performance and timeout issues in HDFS-7929 by using hard-links 
to preserve old edit logs, instead of copying them. (Zhe Zhang via Colin P. 
McCabe)

(cherry picked from commit 7b424f938c3c306795d574792b086d84e4f06425)
(cherry picked from commit cbd11681ce8a51d187d91748b67a708681e599de)

Conflicts:
        
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSUpgrade.java


Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/e1b4e69b
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/e1b4e69b
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/e1b4e69b

Branch: refs/heads/sjlee/hdfs-merge
Commit: e1b4e69bf23022af3125e1c6dc4ac05c89e1418f
Parents: db40aec
Author: Colin Patrick Mccabe <cmcc...@cloudera.com>
Authored: Mon Jun 22 14:37:10 2015 -0700
Committer: Sangjin Lee <sj...@apache.org>
Committed: Thu Aug 13 23:59:46 2015 -0700

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 .../hdfs/server/namenode/NNUpgradeUtil.java       | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)
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http://git-wip-us.apache.org/repos/asf/hadoop/blob/e1b4e69b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNUpgradeUtil.java
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diff --git 
a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNUpgradeUtil.java
 
b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNUpgradeUtil.java
index c01b11d..a4d9580 100644
--- 
a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNUpgradeUtil.java
+++ 
b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNUpgradeUtil.java
@@ -20,6 +20,7 @@ package org.apache.hadoop.hdfs.server.namenode;
 import java.io.File;
 import java.io.FilenameFilter;
 import java.io.IOException;
+import java.nio.file.Files;
 import java.util.List;
 
 import org.apache.commons.logging.Log;
@@ -130,23 +131,8 @@ public abstract class NNUpgradeUtil {
 
     for (String s : fileNameList) {
       File prevFile = new File(tmpDir, s);
-      Preconditions.checkState(prevFile.canRead(),
-          "Edits log file " + s + " is not readable.");
       File newFile = new File(curDir, prevFile.getName());
-      Preconditions.checkState(newFile.createNewFile(),
-          "Cannot create new edits log file in " + curDir);
-      EditLogFileInputStream in = new EditLogFileInputStream(prevFile);
-      EditLogFileOutputStream out =
-          new EditLogFileOutputStream(conf, newFile, 512*1024);
-      FSEditLogOp logOp = in.nextValidOp();
-      while (logOp != null) {
-        out.write(logOp);
-        logOp = in.nextOp();
-      }
-      out.setReadyToFlush();
-      out.flushAndSync(true);
-      out.close();
-      in.close();
+      Files.createLink(newFile.toPath(), prevFile.toPath());
     }
   }