diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 00781b1a65d..52b5f613623 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -156,6 +156,9 @@ Release 2.0.1-alpha - UNRELEASED
     HDFS-3266. DFSTestUtil#waitCorruptReplicas doesn't sleep between checks.
     (Madhukara Phatak via atm)
 
+    HDFS-3505. DirectoryScanner does not join all threads in shutdown.
+    (Colin Patrick McCabe via eli)
+
 Release 2.0.0-alpha - 05-23-2012
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DirectoryScanner.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DirectoryScanner.java
index eac68d970b9..3a143357ac8 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DirectoryScanner.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DirectoryScanner.java
@@ -302,6 +302,22 @@ public class DirectoryScanner implements Runnable {
     shouldRun = false;
     if (masterThread != null) masterThread.shutdown();
     if (reportCompileThreadPool != null) reportCompileThreadPool.shutdown();
+    if (masterThread != null) {
+      try {
+        masterThread.awaitTermination(1, TimeUnit.MINUTES);
+      } catch (InterruptedException e) {
+        LOG.error("interrupted while waiting for masterThread to " +
+          "terminate", e);
+      }
+    }
+    if (reportCompileThreadPool != null) {
+      try {
+        reportCompileThreadPool.awaitTermination(1, TimeUnit.MINUTES);
+      } catch (InterruptedException e) {
+        LOG.error("interrupted while waiting for reportCompileThreadPool to " +
+          "terminate", e);
+      }
+    }
     if (!retainDiffs) clear();
   }