diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 0af5642ee83..62ae8b7bc12 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -124,6 +124,9 @@ Release 2.1.1-beta - UNRELEASED
 
     HDFS-5103. TestDirectoryScanner fails on Windows. (Chuan Liu via cnauroth)
 
+    HDFS-5102. Snapshot names should not be allowed to contain slash characters.
+    (jing9)
+
 Release 2.1.0-beta - 2013-08-22
 
   INCOMPATIBLE CHANGES
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 e4bf91c3c4f..b99a86188f1 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
@@ -2093,6 +2093,10 @@ public class FSDirectory implements Closeable {
   /** Verify if the snapshot name is legal. */
   void verifySnapshotName(String snapshotName, String path)
       throws PathComponentTooLongException {
+    if (snapshotName.contains(Path.SEPARATOR)) {
+      throw new HadoopIllegalArgumentException(
+          "Snapshot name cannot contain \"" + Path.SEPARATOR + "\"");
+    }
     final byte[] bytes = DFSUtil.string2Bytes(snapshotName);
     verifyINodeName(bytes);
     verifyMaxComponentLength(bytes, path, 0);
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshot.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshot.java
index f8a8eb8f61a..a6517258367 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshot.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshot.java
@@ -44,6 +44,7 @@ import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
 import org.apache.hadoop.hdfs.server.namenode.FSDirectory;
 import org.apache.hadoop.hdfs.server.namenode.FSImageTestUtil;
@@ -54,6 +55,7 @@ import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotTestHelper.TestDi
 import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotTestHelper.TestDirectoryTree.Node;
 import org.apache.hadoop.hdfs.tools.offlineImageViewer.OfflineImageViewer;
 import org.apache.hadoop.hdfs.tools.offlineImageViewer.XmlImageVisitor;
+import org.apache.hadoop.ipc.RemoteException;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.util.Time;
 import org.apache.log4j.Level;
@@ -341,6 +343,37 @@ public class TestSnapshot {
     assertEquals(oldStatus.getAccessTime(), snapshotStatus.getAccessTime());
   }
   
+  /**
+   * Test creating a snapshot with illegal name
+   */
+  @Test
+  public void testCreateSnapshotWithIllegalName() throws Exception {
+    final Path dir = new Path("/dir");
+    hdfs.mkdirs(dir);
+    
+    final String name1 = HdfsConstants.DOT_SNAPSHOT_DIR;
+    try {
+      hdfs.createSnapshot(dir, name1);
+      fail("Exception expected when an illegal name is given");
+    } catch (RemoteException e) {
+      String errorMsg = "\"" + HdfsConstants.DOT_SNAPSHOT_DIR
+          + "\" is a reserved name.";
+      GenericTestUtils.assertExceptionContains(errorMsg, e);
+    }
+    
+    String errorMsg = "Snapshot name cannot contain \"" + Path.SEPARATOR + "\"";
+    final String[] badNames = new String[] { "foo" + Path.SEPARATOR,
+        Path.SEPARATOR + "foo", Path.SEPARATOR, "foo" + Path.SEPARATOR + "bar" };
+    for (String badName : badNames) {
+      try {
+        hdfs.createSnapshot(dir, badName);
+        fail("Exception expected when an illegal name is given");
+      } catch (RemoteException e) {
+        GenericTestUtils.assertExceptionContains(errorMsg, e);
+      }
+    }
+  }
+  
   /**
    * Creating snapshots for a directory that is not snapshottable must fail.
    */
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshotRename.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshotRename.java
index ab1752a166d..386563bea1f 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshotRename.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/snapshot/TestSnapshotRename.java
@@ -20,6 +20,7 @@ package org.apache.hadoop.hdfs.server.namenode.snapshot;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 import java.util.List;
 
@@ -29,11 +30,14 @@ import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.SnapshotException;
 import org.apache.hadoop.hdfs.server.namenode.FSDirectory;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot.DirectoryDiff;
 import org.apache.hadoop.hdfs.util.ReadOnlyList;
+import org.apache.hadoop.ipc.RemoteException;
+import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
@@ -190,4 +194,36 @@ public class TestSnapshotRename {
     exception.expectMessage(error);
     hdfs.renameSnapshot(sub1, "s1", "s2");
   }
+  
+  /**
+   * Test renaming a snapshot with illegal name
+   */
+  @Test
+  public void testRenameWithIllegalName() throws Exception {
+    DFSTestUtil.createFile(hdfs, file1, BLOCKSIZE, REPLICATION, seed);
+    // Create snapshots for sub1
+    SnapshotTestHelper.createSnapshot(hdfs, sub1, "s1");
+    
+    final String name1 = HdfsConstants.DOT_SNAPSHOT_DIR;
+    try {
+      hdfs.renameSnapshot(sub1, "s1", name1);
+      fail("Exception expected when an illegal name is given for rename");
+    } catch (RemoteException e) {
+      String errorMsg = "\"" + HdfsConstants.DOT_SNAPSHOT_DIR
+          + "\" is a reserved name.";
+      GenericTestUtils.assertExceptionContains(errorMsg, e);
+    }
+    
+    String errorMsg = "Snapshot name cannot contain \"" + Path.SEPARATOR + "\"";
+    final String[] badNames = new String[] { "foo" + Path.SEPARATOR,
+        Path.SEPARATOR + "foo", Path.SEPARATOR, "foo" + Path.SEPARATOR + "bar" };
+    for (String badName : badNames) {
+      try {
+        hdfs.renameSnapshot(sub1, "s1", badName);
+        fail("Exception expected when an illegal name is given");
+      } catch (RemoteException e) {
+        GenericTestUtils.assertExceptionContains(errorMsg, e);
+      }
+    }
+  }
 }