HDFS-9003. ForkJoin thread pool leaks. Contributed by Kihwal Lee.

(cherry picked from commit de928d566a119f0b7fa5f171719642cd86be0af7)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -935,6 +935,8 @@ Release 2.8.0 - UNRELEASED
     HDFS-8388. Time and Date format need to be in sync in NameNode UI page.
     (Surendra Singh Lilhore via aajisaka)
 
+    HDFS-9003. ForkJoin thread pool leaks. (Kihwal Lee via jing9)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSImage.java

@@ -884,6 +884,7 @@ public class FSImage implements Closeable {
         root, counts);
     p.execute(task);
     task.join();
+    p.shutdown();
     LOG.info("Quota initialization completed in " + (Time.now() - start) +
         " milliseconds\n" + counts);
   }