From 3c6c1d973cb978166da32451503e9a8d0d1063b5 Mon Sep 17 00:00:00 2001
From: emopers <emopers@gmail.com>
Date: Mon, 28 Dec 2015 08:59:56 -0600
Subject: [PATCH] Added synchronized when iterating over synchronizedList as
 per Java specification

---
 .../org/apache/hadoop/hdfs/server/namenode/NNStorage.java   | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNStorage.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNStorage.java
index ed36b27d2e1e3..bbd5f4428d604 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNStorage.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNStorage.java
@@ -836,8 +836,10 @@ void setDisablePreUpgradableLayoutCheck(boolean val) {
    * @param sds A list of storage directories to mark as errored.
    */
   void reportErrorsOnDirectories(List<StorageDirectory> sds) {
-    for (StorageDirectory sd : sds) {
-      reportErrorsOnDirectory(sd);
+    synchronized(sds) {
+      for (StorageDirectory sd : sds) {
+        reportErrorsOnDirectory(sd);
+      }
     }
   }