svn merge -c -1489709 for reverting HDFS-4876.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1489875 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -829,9 +829,6 @@ Release 2.1.0-beta - UNRELEASED
     HDFS-4826. TestNestedSnapshots times out due to repeated slow edit log
     flushes when running on virtualized disk.  (Chris Nauroth via szetszwo)
 
-    HDFS-4876. Fix the javadoc of FileWithSnapshot and move FileDiffList to
-    FileWithSnapshot.  (szetszwo)
-
 Release 2.0.5-alpha - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImageFormat.java

@@ -50,7 +50,7 @@ import org.apache.hadoop.hdfs.protocol.LayoutVersion.Feature;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
 import org.apache.hadoop.hdfs.server.common.InconsistentFSStateException;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiffList;
+import org.apache.hadoop.hdfs.server.namenode.snapshot.FileDiffList;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectorySnapshottable;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileUnderConstructionWithSnapshot;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFile.java

@@ -23,15 +23,17 @@ import java.io.PrintWriter;
 import java.util.List;
 
 import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.fs.permission.FsAction;
+import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockCollection;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
+import org.apache.hadoop.hdfs.server.namenode.snapshot.FileDiffList;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiff;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiffList;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.Util;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeMap.java

@@ -45,7 +45,7 @@ public class INodeMap {
   }
   
   /** Synchronized by external lock. */
-  private final GSet<INode, INodeWithAdditionalFields> map;
+  private GSet<INode, INodeWithAdditionalFields> map;
   
   private INodeMap(GSet<INode, INodeWithAdditionalFields> map) {
     Preconditions.checkArgument(map != null);

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/FileDiffList.java

@@ -0,0 +1,57 @@
+/**
+ * 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.snapshot;
+
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.hdfs.server.namenode.INodeFile;
+import org.apache.hadoop.hdfs.server.namenode.INodeFileUnderConstruction;
+import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiff;
+
+/**
+ * A list of FileDiffs for storing snapshot data.
+ */
+@InterfaceAudience.Private
+public class FileDiffList
+    extends AbstractINodeDiffList<INodeFile, FileDiff> {
+
+  
+  @Override
+  FileDiff createDiff(Snapshot snapshot, INodeFile file) {
+    return new FileDiff(snapshot, file);
+  }
+
+  @Override
+  INodeFile createSnapshotCopy(INodeFile currentINode) {
+    if (currentINode instanceof INodeFileUnderConstructionWithSnapshot) {
+      final INodeFileUnderConstruction uc = 
+          (INodeFileUnderConstruction) currentINode;
+      
+      final INodeFileUnderConstruction copy = new INodeFileUnderConstruction(
+          uc, uc.getClientName(), uc.getClientMachine(), uc.getClientNode());
+      
+      copy.setBlocks(null);
+      return copy;
+    } else {
+      final INodeFile copy = new INodeFile(currentINode);
+      copy.setBlocks(null);
+      return copy;
+    }
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/FileWithSnapshot.java

@@ -27,12 +27,13 @@ import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
 import org.apache.hadoop.hdfs.server.namenode.INode.BlocksMapUpdateInfo;
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INodeFile;
-import org.apache.hadoop.hdfs.server.namenode.INodeFileUnderConstruction;
 import org.apache.hadoop.hdfs.server.namenode.Quota;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat.ReferenceMap;
 
 /**
- * An interface for {@link INodeFile} to support snapshot.
+ * {@link INodeFile} with a link to the next element.
+ * The link of all the snapshot files and the original file form a circular
+ * linked list so that all elements are accessible by any of the elements.
  */
 @InterfaceAudience.Private
 public interface FileWithSnapshot {
@@ -43,7 +44,7 @@ public interface FileWithSnapshot {
     /** The file size at snapshot creation time. */
     private final long fileSize;
 
-    private FileDiff(Snapshot snapshot, INodeFile file) {
+    FileDiff(Snapshot snapshot, INodeFile file) {
       super(snapshot, null, null);
       fileSize = file.computeFileSize();
     }
@@ -118,34 +119,6 @@ public interface FileWithSnapshot {
     }
   }
 
-  /** A list of FileDiffs for storing snapshot data. */
-  public static class FileDiffList
-      extends AbstractINodeDiffList<INodeFile, FileDiff> {
-
-    @Override
-    FileDiff createDiff(Snapshot snapshot, INodeFile file) {
-      return new FileDiff(snapshot, file);
-    }
-    
-    @Override
-    INodeFile createSnapshotCopy(INodeFile currentINode) {
-      if (currentINode instanceof INodeFileUnderConstructionWithSnapshot) {
-        final INodeFileUnderConstruction uc = 
-            (INodeFileUnderConstruction) currentINode;
-        
-        final INodeFileUnderConstruction copy = new INodeFileUnderConstruction(
-            uc, uc.getClientName(), uc.getClientMachine(), uc.getClientNode());
-        
-        copy.setBlocks(null);
-        return copy;
-      } else {
-        final INodeFile copy = new INodeFile(currentINode);
-        copy.setBlocks(null);
-        return copy;
-      }
-    }
-  }
-
   /** @return the {@link INodeFile} view of this object. */
   public INodeFile asINodeFile();
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/SnapshotFSImageFormat.java

@@ -34,7 +34,7 @@ import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
 import org.apache.hadoop.hdfs.server.namenode.INodeFile;
 import org.apache.hadoop.hdfs.server.namenode.INodeReference;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiff;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiffList;
+import org.apache.hadoop.hdfs.server.namenode.snapshot.FileDiffList;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot.DirectoryDiff;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot.DirectoryDiffList;
 import org.apache.hadoop.hdfs.tools.snapshot.SnapshotDiff;