HDFS-14618. Incorrect synchronization of ArrayList field (ArrayList is thread-unsafe). Contributed by Paul Ward.

paulward24 · anuengineer · commit d203045c3024 · 2019-06-28T16:06:43.000-07:00
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/PendingReconstructionBlocks.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/PendingReconstructionBlocks.java
@@ -132,7 +132,9 @@ void remove(BlockInfo block) {
   public void clear() {
     synchronized (pendingReconstructions) {
       pendingReconstructions.clear();
-      timedOutItems.clear();
+      synchronized (timedOutItems) {
+        timedOutItems.clear();
+      }
       timedOutCount = 0L;
     }
   }

Original file line number	Diff line number	Diff line change
`@@ -132,7 +132,9 @@ void remove(BlockInfo block) {`
`132`	`132`	`public void clear() {`
`133`	`133`	`synchronized (pendingReconstructions) {`
`134`	`134`	`pendingReconstructions.clear();`
`135`		`- timedOutItems.clear();`
	`135`	`+ synchronized (timedOutItems) {`
	`136`	`+ timedOutItems.clear();`
	`137`	`+ }`
`136`	`138`	`timedOutCount = 0L;`
`137`	`139`	`}`
`138`	`140`	`}`