From e8cb2ae409bc1d62f23efef485d1c6f1ff21e86c Mon Sep 17 00:00:00 2001
From: Ayush Saxena <ayushsaxena@apache.org>
Date: Wed, 3 Jun 2020 12:47:15 +0530
Subject: [PATCH] HDFS-11041. Unable to unregister FsDatasetState MBean if
 DataNode is shutdown twice. Contributed by Wei-Chiu Chuang.

---
 .../hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java   | 1 +
 .../hadoop/hdfs/server/datanode/SimulatedFSDataset.java      | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java
index d6b50e1364b..18a747635f2 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java
@@ -2385,6 +2385,7 @@ public void shutdown() {
 
     if (mbeanName != null) {
       MBeans.unregister(mbeanName);
+      mbeanName = null;
     }
     
     if (asyncDiskService != null) {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java
index 13ad16979ce..8069b64246b 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java
@@ -1367,7 +1367,10 @@ void registerMBean(final String storageId) {
 
   @Override
   public void shutdown() {
-    if (mbeanName != null) MBeans.unregister(mbeanName);
+    if (mbeanName != null) {
+      MBeans.unregister(mbeanName);
+      mbeanName = null;
+    }
   }
 
   @Override