From d95dd33ea115cb3fba25688279a5c9bbaa769da9 Mon Sep 17 00:00:00 2001
From: paulward24 <52216289+paulward24@users.noreply.github.com>
Date: Mon, 1 Jul 2019 13:54:49 -0700
Subject: [PATCH] HDFS-14610. HashMap is not thread safe. Field storageMap is
 typically synchronized by storageMap. However, in one place, field storageMap
 is not protected with synchronized. (#1015)

(cherry picked from commit d8bac50e12d243ef8fd2c7e0ce5c9997131dee74)
(cherry picked from commit 76a91359475444cb6d415e5056430c0e743b88ee)
---
 .../hdfs/server/blockmanagement/DatanodeDescriptor.java    | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java
index 46a4a7e1080..a4e43f2e1ed 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java
@@ -451,8 +451,11 @@ public class DatanodeDescriptor extends DatanodeInfo {
     this.volumeFailureSummary = volumeFailureSummary;
     for (StorageReport report : reports) {
 
-      DatanodeStorageInfo storage =
-          storageMap.get(report.getStorage().getStorageID());
+      DatanodeStorageInfo storage = null;
+      synchronized (storageMap) {
+        storage =
+            storageMap.get(report.getStorage().getStorageID());
+      }
       if (checkFailedStorages) {
         failedStorageInfos.remove(storage);
       }