From ef591b1d6a08f08358b19763a874de6010227307 Mon Sep 17 00:00:00 2001
From: Colin Patrick Mccabe <cmccabe@cloudera.com>
Date: Fri, 3 Apr 2015 16:34:23 -0700
Subject: [PATCH] HDFS-8051. FsVolumeList#addVolume should release volume
 reference if not put it into BlockScanner. (Lei (Eddy) Xu via Colin P.
 McCabe)

---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  3 +++
 .../datanode/fsdataset/impl/FsVolumeList.java |  5 +++++
 .../fsdataset/impl/TestFsVolumeList.java      | 19 +++++++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 2d399a4f5b..6fafec8ee9 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -1376,6 +1376,9 @@ Release 2.7.0 - UNRELEASED
     HDFS-7996. After swapping a volume, BlockReceiver reports
     ReplicaNotFoundException (Lei (Eddy) Xu via Colin P. McCabe)
 
+    HDFS-8051. FsVolumeList#addVolume should release volume reference if not
+    put it into BlockScanner. (Lei (Eddy) Xu via Colin P. McCabe)
+
     BREAKDOWN OF HDFS-7584 SUBTASKS AND RELATED JIRAS
 
       HDFS-7720. Quota by Storage Type API, tools and ClientNameNode
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeList.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeList.java
index 4fddfb9e64..d87595cece 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeList.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeList.java
@@ -41,6 +41,7 @@
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.VolumeChoosingPolicy;
 import org.apache.hadoop.hdfs.server.datanode.BlockScanner;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
+import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.util.DiskChecker.DiskErrorException;
 import org.apache.hadoop.util.Time;
 
@@ -292,6 +293,10 @@ void addVolume(FsVolumeReference ref) {
     }
     if (blockScanner != null) {
       blockScanner.addVolumeScanner(ref);
+    } else {
+      // If the volume is not put into a volume scanner, it does not need to
+      // hold the reference.
+      IOUtils.cleanup(FsDatasetImpl.LOG, ref);
     }
     // If the volume is used to replace a failed volume, it needs to reset the
     // volume failure info for this volume.
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestFsVolumeList.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestFsVolumeList.java
index 46189ba6df..eccff896bf 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestFsVolumeList.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestFsVolumeList.java
@@ -35,6 +35,7 @@
 import java.util.List;
 
 import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.fail;
 import static org.mockito.Mockito.mock;
 
 public class TestFsVolumeList {
@@ -101,4 +102,22 @@ public void testCheckDirsWithClosedVolume() throws IOException {
     // checkDirs() should ignore the 2nd volume since it is closed.
     volumeList.checkDirs();
   }
+
+  @Test
+  public void testReleaseVolumeRefIfNoBlockScanner() throws IOException {
+    FsVolumeList volumeList = new FsVolumeList(
+        Collections.<VolumeFailureInfo>emptyList(), null, blockChooser);
+    File volDir = new File(baseDir, "volume-0");
+    volDir.mkdirs();
+    FsVolumeImpl volume = new FsVolumeImpl(dataset, "storage-id", volDir,
+        conf, StorageType.DEFAULT);
+    FsVolumeReference ref = volume.obtainReference();
+    volumeList.addVolume(ref);
+    try {
+      ref.close();
+      fail("Should throw exception because the reference is closed in "
+          + "VolumeList#addVolume().");
+    } catch (IllegalStateException e) {
+    }
+  }
 }