From 8dfef7d2dcc3d6b695d1a5794a15458428a12d1a Mon Sep 17 00:00:00 2001
From: Tsz-wo Sze <szetszwo@apache.org>
Date: Tue, 31 Jan 2012 17:36:42 +0000
Subject: [PATCH] HDFS-2827.  When the parent of a directory is the root,
 renaming the directory results in leases updated incorrectly.  Contributed by
 Uma Maheswara Rao G

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1238700 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  4 ++
 .../hdfs/server/namenode/FSNamesystem.java    | 11 +++++-
 .../server/namenode/TestSaveNamespace.java    | 39 +++++++++++++++++--
 3 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 6257c48f43..3277ab2fc4 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -378,6 +378,10 @@ Release 0.23.1 - UNRELEASED
     HDFS-2791. If block report races with closing of file, replica is
     incorrectly marked corrupt. (todd)
 
+    HDFS-2827.  When the parent of a directory is the root, renaming the
+    directory results in leases updated incorrectly.  (Uma Maheswara Rao G
+    via szetszwo)
+
 Release 0.23.0 - 2011-11-01 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
index c718c7dffd..efd6b9fb96 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
@@ -3907,7 +3907,12 @@ void unprotectedChangeLease(String src, String dst, HdfsFileStatus dinfo) {
 
     if (destinationExisted && dinfo.isDir()) {
       Path spath = new Path(src);
-      overwrite = spath.getParent().toString() + Path.SEPARATOR;
+      Path parent = spath.getParent();
+      if (isRoot(parent)) {
+        overwrite = parent.toString();
+      } else {
+        overwrite = parent.toString() + Path.SEPARATOR;
+      }
       replaceBy = dst + Path.SEPARATOR;
     } else {
       overwrite = src;
@@ -3917,6 +3922,10 @@ void unprotectedChangeLease(String src, String dst, HdfsFileStatus dinfo) {
     leaseManager.changeLease(src, dst, overwrite, replaceBy);
   }
            
+  private boolean isRoot(Path path) {
+    return path.getParent() == null;
+  }
+
   /**
    * Serializes leases. 
    */
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestSaveNamespace.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestSaveNamespace.java
index 25a458b0c4..ed2162b7b9 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestSaveNamespace.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestSaveNamespace.java
@@ -18,9 +18,10 @@
 package org.apache.hadoop.hdfs.server.namenode;
 
 import static org.apache.hadoop.hdfs.server.common.Util.fileAsURI;
-
-import static org.junit.Assert.*;
-
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 import static org.mockito.Matchers.anyObject;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doThrow;
@@ -28,6 +29,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -38,16 +40,19 @@
 import org.apache.commons.logging.impl.Log4JLogger;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
+import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.NamenodeRole;
 import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
 import org.apache.hadoop.hdfs.util.MD5FileUtils;
+import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.test.GenericTestUtils.DelayAnswer;
 import org.apache.log4j.Level;
@@ -565,6 +570,34 @@ public Void call() throws Exception {
       }
     }
   }
+
+  /**
+   * Test for save namespace should succeed when parent directory renamed with
+   * open lease and destination directory exist. 
+   * This test is a regression for HDFS-2827
+   */
+  @Test
+  public void testSaveNamespaceWithRenamedLease() throws Exception {
+    MiniDFSCluster cluster = new MiniDFSCluster.Builder(new Configuration())
+        .numDataNodes(1).build();
+    cluster.waitActive();
+    DistributedFileSystem fs = (DistributedFileSystem) cluster.getFileSystem();
+    OutputStream out = null;
+    try {
+      fs.mkdirs(new Path("/test-target"));
+      out = fs.create(new Path("/test-source/foo")); // don't close
+      fs.rename(new Path("/test-source/"), new Path("/test-target/"));
+
+      fs.setSafeMode(SafeModeAction.SAFEMODE_ENTER);
+      cluster.getNameNodeRpc().saveNamespace();
+      fs.setSafeMode(SafeModeAction.SAFEMODE_LEAVE);
+    } finally {
+      IOUtils.cleanup(LOG, out, fs);
+      if (cluster != null) {
+        cluster.shutdown();
+      }
+    }
+  }
   
   private void doAnEdit(FSNamesystem fsn, int id) throws IOException {
     // Make an edit