From 6f1ef980ded061dd75d3368b0fc2fbbed14eea9f Mon Sep 17 00:00:00 2001
From: Konstantin Shvachko <shv@apache.org>
Date: Wed, 27 Jul 2011 23:28:16 +0000
Subject: [PATCH] HDFS-1981. NameNode does not saveNamespace() when editsNew is
 empty. Contributed by Uma Maheswara Rao G.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1151666 13f79535-47bb-0310-9956-ffa450edef68
---
 hdfs/CHANGES.txt                              |  3 +
 .../hadoop/hdfs/server/namenode/FSImage.java  |  4 +-
 .../hdfs/server/namenode/TestFSImage.java     | 91 +++++++++++++++++++
 3 files changed, 97 insertions(+), 1 deletion(-)
 create mode 100644 hdfs/src/test/hdfs/org/apache/hadoop/hdfs/server/namenode/TestFSImage.java

diff --git a/hdfs/CHANGES.txt b/hdfs/CHANGES.txt
index a44224779e3..e7beb78b811 100644
--- a/hdfs/CHANGES.txt
+++ b/hdfs/CHANGES.txt
@@ -1382,6 +1382,9 @@ Release 0.22.0 - Unreleased
     HDFS-2071. Use of isConnected() in DataXceiver is invalid. (Kihwal Lee
     via todd)
 
+    HDFS-1981. NameNode does not saveNamespace() when editsNew is empty.
+    (Uma Maheswara Rao G via shv)
+
 Release 0.21.1 - Unreleased
     HDFS-1466. TestFcHdfsSymlink relies on /tmp/test not existing. (eli)
 
diff --git a/hdfs/src/java/org/apache/hadoop/hdfs/server/namenode/FSImage.java b/hdfs/src/java/org/apache/hadoop/hdfs/server/namenode/FSImage.java
index f81ee730f59..3883f832d33 100644
--- a/hdfs/src/java/org/apache/hadoop/hdfs/server/namenode/FSImage.java
+++ b/hdfs/src/java/org/apache/hadoop/hdfs/server/namenode/FSImage.java
@@ -763,7 +763,9 @@ public class FSImage implements NNStorageListener, Closeable {
       numEdits += loader.loadFSEdits(edits);
       edits.close();
     }
-    
+    if (numEdits == 0 && editsNew.exists()) {
+      numEdits++;
+    }
     // update the counts.
     getFSNamesystem().dir.updateCountForINodeWithQuota();    
     
diff --git a/hdfs/src/test/hdfs/org/apache/hadoop/hdfs/server/namenode/TestFSImage.java b/hdfs/src/test/hdfs/org/apache/hadoop/hdfs/server/namenode/TestFSImage.java
new file mode 100644
index 00000000000..e92134e366c
--- /dev/null
+++ b/hdfs/src/test/hdfs/org/apache/hadoop/hdfs/server/namenode/TestFSImage.java
@@ -0,0 +1,91 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.net.URI;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileUtil;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.io.IOUtils;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class TestFSImage {
+
+  private static final String OUT_DIR = System.getProperty("test.build.data",
+      "build/test/fsimage");
+
+  private MiniDFSCluster miniDFSCluster = null;
+
+  private static Configuration nnConf = new Configuration();
+
+  private File current = new File(OUT_DIR);
+
+  @Before
+  public void setUpCluster() throws Exception {
+    clearDirs();
+  }
+
+  @After
+  public void clusterShutdown() throws Exception {
+    if (null != miniDFSCluster) {
+      miniDFSCluster.shutdown();
+    }
+  }
+
+  @Test
+  public void testLoadFsEditsShouldReturnTrueWhenEditsNewExists()
+      throws Exception {
+    nnConf.set(DFSConfigKeys.DFS_NAMENODE_NAME_DIR_KEY, OUT_DIR + "/BNN1");
+    NameNode.format(nnConf);
+    miniDFSCluster = new MiniDFSCluster.Builder(nnConf).numDataNodes(1).build();
+    FSImage image = miniDFSCluster.getNameNode().getFSImage();
+    URI next = FSNamesystem
+        .getNamespaceDirs(miniDFSCluster.getConfiguration(0)).iterator().next();
+    File editsNew = new File(next.getRawPath() , "/current/edits.new");
+    createEditsNew(editsNew, image);
+    int loadFSEdits = image.loadFSEdits(image.getStorage().getStorageDir(0));
+    assertEquals("The numEdits should not be zero.", 1, loadFSEdits);
+  }
+
+  private void createEditsNew(File editsNew, FSImage image) throws Exception {
+    FileOutputStream fileOutputStream = null;
+    if (!editsNew.exists()) {
+      try {
+        editsNew.createNewFile();
+        image.editLog.createEditLogFile(editsNew);
+      } finally {
+        IOUtils.closeStream(fileOutputStream);
+      }
+    }
+  }
+
+  private void clearDirs() throws IOException {
+    if (current.exists()) {
+      FileUtil.fullyDelete(current);
+    }
+  }
+}