From b437f5eef40874287d4fbf9d8e43f1a857b5621f Mon Sep 17 00:00:00 2001
From: Andrew Wang <wang@apache.org>
Date: Thu, 11 Dec 2014 18:12:47 -0800
Subject: [PATCH] HDFS-7497. Inconsistent report of decommissioning DataNodes
 between dfsadmin and NameNode webui. Contributed by Yongjun Zhang.

---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt          |  3 +++
 .../hdfs/server/blockmanagement/DatanodeManager.java | 12 ++----------
 .../server/namenode/TestDecommissioningStatus.java   |  7 ++++++-
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 5e75424063..5977ed79d2 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -576,6 +576,9 @@ Release 2.7.0 - UNRELEASED
 
     HDFS-7515. Fix new findbugs warnings in hadoop-hdfs. (wheat9)
 
+    HDFS-7497. Inconsistent report of decommissioning DataNodes between
+    dfsadmin and NameNode webui. (Yongjun Zhang via wang)
+
 Release 2.6.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java
index 356a4a3cf0..0ff469a8c8 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java
@@ -1112,16 +1112,8 @@ public int getNumDeadDataNodes() {
   public List<DatanodeDescriptor> getDecommissioningNodes() {
     // There is no need to take namesystem reader lock as
     // getDatanodeListForReport will synchronize on datanodeMap
-    final List<DatanodeDescriptor> decommissioningNodes
-        = new ArrayList<DatanodeDescriptor>();
-    final List<DatanodeDescriptor> results = getDatanodeListForReport(
-        DatanodeReportType.LIVE);
-    for(DatanodeDescriptor node : results) {
-      if (node.isDecommissionInProgress()) {
-        decommissioningNodes.add(node);
-      }
-    }
-    return decommissioningNodes;
+    // A decommissioning DN may be "alive" or "dead".
+    return getDatanodeListForReport(DatanodeReportType.DECOMMISSIONING);
   }
   
   /* Getter and Setter for stale DataNodes related attributes */
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestDecommissioningStatus.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestDecommissioningStatus.java
index 28f5eb497b..a9aba864e9 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestDecommissioningStatus.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestDecommissioningStatus.java
@@ -239,10 +239,10 @@ private void checkDFSAdminDecommissionStatus(
       System.setOut(oldOut);
     }
   }
+
   /**
    * Tests Decommissioning Status in DFS.
    */
-
   @Test
   public void testDecommissionStatus() throws IOException, InterruptedException {
     InetSocketAddress addr = new InetSocketAddress("localhost", cluster
@@ -351,6 +351,11 @@ public void testDecommissionStatusAfterDNRestart()
     assertTrue("the node should be DECOMMISSION_IN_PROGRESSS",
         dead.get(0).isDecommissionInProgress());
 
+    // Check DatanodeManager#getDecommissionNodes, make sure it returns
+    // the node as decommissioning, even if it's dead
+    List<DatanodeDescriptor> decomlist = dm.getDecommissioningNodes();
+    assertTrue("The node should be be decommissioning", decomlist.size() == 1);
+    
     // Delete the under-replicated file, which should let the 
     // DECOMMISSION_IN_PROGRESS node become DECOMMISSIONED
     cleanupFile(fileSys, f);