HDFS-9812. Streamer threads leak if failure happens when closing DFSOutputStream. Contributed by Lin Yiqun.

(cherry picked from commit 352d299cf8ebe330d24117df98d1e6a64ae38c26)
(cherry picked from commit fe0009a2bd17e26f9e9364ec3f772e9a3f138de8)

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSOutputStream.java

@@ -774,14 +774,19 @@ public class DFSOutputStream extends FSOutputSummer
       flushInternal();             // flush all data to Datanodes
       // get last block before destroying the streamer
       ExtendedBlock lastBlock = getStreamer().getBlock();
-      closeThreads(false);
+
       try (TraceScope ignored =
                dfsClient.getTracer().newScope("completeFile")) {
         completeFile(lastBlock);
       }
     } catch (ClosedChannelException ignored) {
     } finally {
-      setClosed();
+      // Failures may happen when flushing data.
+      // Streamers may keep waiting for the new block information.
+      // Thus need to force closing these threads.
+      // Don't need to call setClosed() because closeThreads(true)
+      // calls setClosed() in the finally block.
+      closeThreads(true);
     }
   }