diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-2802.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-2802.txt
index 9be2d5268cc..bcf59fdce6f 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-2802.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-2802.txt
@@ -190,3 +190,5 @@ Branch-2802 Snapshot (Unreleased)
   (Jing Zhao via szetszwo)
 
   HDFS-4579. Annotate snapshot tests. (Arpit Agarwal via suresh)
+
+  HDFS-4574. Move Diff to the util package.  (szetszwo)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirectory.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirectory.java
index 7c21117af7c..1b2da6f4ba6 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirectory.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirectory.java
@@ -1558,7 +1558,7 @@ public class FSDirectory implements Closeable {
   private static INode[] getRelativePathINodes(INode inode, INode ancestor) {
     // calculate the depth of this inode from the ancestor
     int depth = 0;
-    for (INode i = inode; i != null && !i.equals(ancestor); i = i.parent) {
+    for (INode i = inode; i != null && !i.equals(ancestor); i = i.getParent()) {
       depth++;
     }
     INode[] inodes = new INode[depth];
@@ -1571,7 +1571,7 @@ public class FSDirectory implements Closeable {
         return null;
       }
       inodes[depth-i-1] = inode;
-      inode = inode.parent;
+      inode = inode.getParent();
     }
     return inodes;
   }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INode.java
index 4d2953a11ed..f951ce85b55 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INode.java
@@ -34,8 +34,10 @@ import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.NSQuotaExceededException;
 import org.apache.hadoop.hdfs.server.namenode.INode.Content.CountsMap.Key;
+import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot;
+import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.diff.Diff;
+import org.apache.hadoop.hdfs.util.Diff;
 import org.apache.hadoop.util.StringUtils;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -109,7 +111,7 @@ public abstract class INode implements Diff.Element<byte[]> {
    * should not modify it.
    */
   private long permission = 0L;
-  INodeDirectory parent = null;
+  private INodeDirectory parent = null;
   private long modificationTime = 0L;
   private long accessTime = 0L;
 
@@ -509,16 +511,6 @@ public abstract class INode implements Diff.Element<byte[]> {
     return name == null? null: DFSUtil.bytes2String(name);
   }
 
-
-  String getLocalParentDir() {
-    INode inode = isRoot() ? this : getParent();
-    String parentDir = "";
-    if (inode != null) {
-      parentDir = inode.getFullPathName();
-    }
-    return (parentDir != null) ? parentDir : "";
-  }
-
   /**
    * @return null if the local name is null;
    *         otherwise, return the local name byte array.
@@ -532,13 +524,6 @@ public abstract class INode implements Diff.Element<byte[]> {
     return getLocalNameBytes();
   }
 
-  /**
-   * Set local file name
-   */
-  public void setLocalName(String name) {
-    setLocalName(DFSUtil.string2Bytes(name));
-  }
-
   /**
    * Set local file name
    */
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeDirectory.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeDirectory.java
index 0f65a5edf9b..3035991c39e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeDirectory.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeDirectory.java
@@ -82,7 +82,7 @@ public class INodeDirectory extends INode {
     this.children = other.children;
     if (adopt && this.children != null) {
       for (INode child : children) {
-        child.parent = this;
+        child.setParent(this);
       }
     }
   }
@@ -529,7 +529,7 @@ public class INodeDirectory extends INode {
     if (children == null) {
       children = new ArrayList<INode>(DEFAULT_FILES_PER_DIRECTORY);
     }
-    node.parent = this;
+    node.setParent(this);
     children.add(-insertionPoint - 1, node);
 
     if (node.getGroupName() == null) {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFile.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFile.java
index d4b639d2c80..8fe9886e6b6 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFile.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFile.java
@@ -157,7 +157,7 @@ public class INodeFile extends INode implements BlockCollection {
   public INodeFile recordModification(final Snapshot latest)
       throws NSQuotaExceededException {
     return isInLatestSnapshot(latest)?
-        parent.replaceChild4INodeFileWithSnapshot(this)
+        getParent().replaceChild4INodeFileWithSnapshot(this)
             .recordModification(latest)
         : this;
   }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFileUnderConstruction.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFileUnderConstruction.java
index 800ed15ed83..ff1075d45d1 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFileUnderConstruction.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeFileUnderConstruction.java
@@ -133,7 +133,7 @@ public class INodeFileUnderConstruction extends INodeFile implements MutableBloc
   public INodeFileUnderConstruction recordModification(final Snapshot latest)
       throws NSQuotaExceededException {
     return isInLatestSnapshot(latest)?
-        parent.replaceChild4INodeFileUcWithSnapshot(this)
+        getParent().replaceChild4INodeFileUcWithSnapshot(this)
             .recordModification(latest)
         : this;
   }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeSymlink.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeSymlink.java
index 2532d1d2e6f..916334e34c1 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeSymlink.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeSymlink.java
@@ -47,7 +47,7 @@ public class INodeSymlink extends INode {
   @Override
   INode recordModification(Snapshot latest) throws NSQuotaExceededException {
     return isInLatestSnapshot(latest)?
-        parent.saveChild2Snapshot(this, latest, new INodeSymlink(this))
+        getParent().saveChild2Snapshot(this, latest, new INodeSymlink(this))
         : this;
   }
 
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NamenodeJspHelper.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NamenodeJspHelper.java
index d13ace018d6..321d9262acd 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NamenodeJspHelper.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NamenodeJspHelper.java
@@ -775,7 +775,16 @@ class NamenodeJspHelper {
       }
     }
   }
-  
+
+  private static String getLocalParentDir(INode inode) {
+    final INode parent = inode.isRoot() ? inode : inode.getParent();
+    String parentDir = "";
+    if (parent != null) {
+      parentDir = parent.getFullPathName();
+    }
+    return (parentDir != null) ? parentDir : "";
+  }
+
   // utility class used in block_info_xml.jsp
   static class XMLBlockInfo {
     final Block block;
@@ -817,7 +826,7 @@ class NamenodeJspHelper {
           doc.endTag();
 
           doc.startTag("local_directory");
-          doc.pcdata(inode.getLocalParentDir());
+          doc.pcdata(getLocalParentDir(inode));
           doc.endTag();
 
           doc.startTag("user_name");
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/INodeDirectorySnapshottable.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/INodeDirectorySnapshottable.java
index a9db43fd194..cc18844a23c 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/INodeDirectorySnapshottable.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/INodeDirectorySnapshottable.java
@@ -227,7 +227,8 @@ public class INodeDirectorySnapshottable extends INodeDirectoryWithSnapshot {
       throw new SnapshotException("The snapshot " + oldName
           + " does not exist for directory " + path);
     } else {
-      int indexOfNew = searchSnapshot(DFSUtil.string2Bytes(newName));
+      final byte[] newNameBytes = DFSUtil.string2Bytes(newName);
+      int indexOfNew = searchSnapshot(newNameBytes);
       if (indexOfNew > 0) {
         throw new SnapshotException("The snapshot " + newName
             + " already exists for directory " + path);
@@ -235,7 +236,7 @@ public class INodeDirectorySnapshottable extends INodeDirectoryWithSnapshot {
       // remove the one with old name from snapshotsByNames
       Snapshot snapshot = snapshotsByNames.remove(indexOfOld);
       final INodeDirectory ssRoot = snapshot.getRoot();
-      ssRoot.setLocalName(newName);
+      ssRoot.setLocalName(newNameBytes);
       indexOfNew = -indexOfNew - 1;
       if (indexOfNew <= indexOfOld) {
         snapshotsByNames.add(indexOfNew, snapshot);
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/INodeDirectoryWithSnapshot.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/INodeDirectoryWithSnapshot.java
index 58d8cc8ca6f..57476acb7e7 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/INodeDirectoryWithSnapshot.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/INodeDirectoryWithSnapshot.java
@@ -30,13 +30,13 @@ import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffType;
 import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
 import org.apache.hadoop.hdfs.server.namenode.INode;
-import org.apache.hadoop.hdfs.server.namenode.Quota;
 import org.apache.hadoop.hdfs.server.namenode.INode.Content.CountsMap.Key;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectoryWithQuota;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.diff.Diff;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.diff.Diff.Container;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.diff.Diff.UndoInfo;
+import org.apache.hadoop.hdfs.server.namenode.Quota;
+import org.apache.hadoop.hdfs.util.Diff;
+import org.apache.hadoop.hdfs.util.Diff.Container;
+import org.apache.hadoop.hdfs.util.Diff.UndoInfo;
 import org.apache.hadoop.hdfs.util.ReadOnlyList;
 
 import com.google.common.base.Preconditions;
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/diff/Diff.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/util/Diff.java
similarity index 99%
rename from hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/diff/Diff.java
rename to hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/util/Diff.java
index af85cc0840b..b912d218596 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/diff/Diff.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/util/Diff.java
@@ -15,7 +15,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.hadoop.hdfs.server.namenode.snapshot.diff;
+package org.apache.hadoop.hdfs.util;
 
 import java.util.ArrayList;
 import java.util.Collections;
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestINodeFile.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestINodeFile.java
index 89792c88ba1..e8b7efc58dc 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestINodeFile.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestINodeFile.java
@@ -139,7 +139,7 @@ public class TestINodeFile {
     replication = 3;
     preferredBlockSize = 128*1024*1024;
     INodeFile inf = createINodeFile(replication, preferredBlockSize);
-    inf.setLocalName("f");
+    inf.setLocalName(DFSUtil.string2Bytes("f"));
 
     INodeDirectory root = new INodeDirectory(INodeId.GRANDFATHER_INODE_ID,
         INodeDirectory.ROOT_NAME, perm, 0L);
@@ -147,19 +147,15 @@ public class TestINodeFile {
         DFSUtil.string2Bytes("d"), perm, 0L);
 
     assertEquals("f", inf.getFullPathName());
-    assertEquals("", inf.getLocalParentDir());
 
     dir.addChild(inf);
     assertEquals("d"+Path.SEPARATOR+"f", inf.getFullPathName());
-    assertEquals("d", inf.getLocalParentDir());
     
     root.addChild(dir);
     assertEquals(Path.SEPARATOR+"d"+Path.SEPARATOR+"f", inf.getFullPathName());
     assertEquals(Path.SEPARATOR+"d", dir.getFullPathName());
 
     assertEquals(Path.SEPARATOR, root.getFullPathName());
-    assertEquals(Path.SEPARATOR, root.getLocalParentDir());
-    
   }
   
   /**
@@ -229,7 +225,7 @@ public class TestINodeFile {
     for (int i = 0; i < nCount; i++) {
       iNodes[i] = new INodeFile(i, null, perm, 0L, 0L, null, replication,
           preferredBlockSize);
-      iNodes[i].setLocalName(fileNamePrefix +  Integer.toString(i));
+      iNodes[i].setLocalName(DFSUtil.string2Bytes(fileNamePrefix + i));
       BlockInfo newblock = new BlockInfo(replication);
       iNodes[i].addBlock(newblock);
     }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/diff/TestDiff.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/util/TestDiff.java
similarity index 97%
rename from hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/diff/TestDiff.java
rename to hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/util/TestDiff.java
index c3d8b89cea8..f8cb13b4569 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/diff/TestDiff.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/util/TestDiff.java
@@ -15,7 +15,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.hadoop.hdfs.server.namenode.snapshot.diff;
+package org.apache.hadoop.hdfs.util;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -26,8 +26,9 @@ import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.diff.Diff.Container;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.diff.Diff.UndoInfo;
+import org.apache.hadoop.hdfs.util.Diff;
+import org.apache.hadoop.hdfs.util.Diff.Container;
+import org.apache.hadoop.hdfs.util.Diff.UndoInfo;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -45,7 +46,7 @@ public class TestDiff {
   }
 
   /** Test directory diff. */
-  @Test
+  @Test(timeout=60000)
   public void testDiff() throws Exception {
     for(int startSize = 0; startSize <= 1000; startSize = nextStep(startSize)) {
       for(int m = 0; m <= 10000; m = nextStep(m)) {