HDFS-11915. Sync rbw dir on the first hsync() to avoid file lost on power failure. Contributed by Vinayakumar B.

(cherry picked from commit d6c31a3e6b60c4b8af9ae4661f16614805654e59)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockReceiver.java

@@ -126,6 +126,7 @@ class BlockReceiver implements Closeable {
 
   private boolean syncOnClose;
   private volatile boolean dirSyncOnFinalize;
+  private boolean dirSyncOnHSyncDone = false;
   private long restartBudget;
   /** the reference of the volume where the block receiver writes to */
   private ReplicaHandler replicaHandler;
@@ -424,6 +425,10 @@ class BlockReceiver implements Closeable {
       }
       flushTotalNanos += flushEndNanos - flushStartNanos;
     }
+    if (isSync && !dirSyncOnHSyncDone && replicaInfo instanceof LocalReplica) {
+      ((LocalReplica) replicaInfo).fsyncDirectory();
+      dirSyncOnHSyncDone = true;
+    }
     if (checksumOut != null || streams.getDataOut() != null) {
       datanode.metrics.addFlushNanos(flushTotalNanos);
       if (isSync) {