From 9fded678ffcda12b980ab8f01914168de38a8c73 Mon Sep 17 00:00:00 2001
From: supratimdeka <46919641+supratimdeka@users.noreply.github.com>
Date: Thu, 6 Jun 2019 18:53:37 +0530
Subject: [PATCH] HDDS-1621. writeData in ChunkUtils should not use
 AsynchronousFileChannel. Contributed by Supratim Deka (#917)

---
 .../keyvalue/helpers/ChunkUtils.java          | 22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/keyvalue/helpers/ChunkUtils.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/keyvalue/helpers/ChunkUtils.java
index 2781bfacca..2993bbb81a 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/keyvalue/helpers/ChunkUtils.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/keyvalue/helpers/ChunkUtils.java
@@ -43,6 +43,7 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.AsynchronousFileChannel;
+import java.nio.channels.FileChannel;
 import java.nio.channels.FileLock;
 import java.nio.file.StandardOpenOption;
 import java.security.NoSuchAlgorithmException;
@@ -84,23 +85,20 @@ public static void writeData(File chunkFile, ChunkInfo chunkInfo,
       throw new StorageContainerException(err, INVALID_WRITE_SIZE);
     }
 
-    AsynchronousFileChannel file = null;
+    FileChannel file = null;
     FileLock lock = null;
 
     try {
       long writeTimeStart = Time.monotonicNow();
-      file = sync ?
-          AsynchronousFileChannel.open(chunkFile.toPath(),
-              StandardOpenOption.CREATE,
-              StandardOpenOption.WRITE,
-              StandardOpenOption.SPARSE,
-              StandardOpenOption.SYNC) :
-          AsynchronousFileChannel.open(chunkFile.toPath(),
+
+      // skip SYNC and DSYNC to reduce contention on file.lock
+      file = FileChannel.open(chunkFile.toPath(),
               StandardOpenOption.CREATE,
               StandardOpenOption.WRITE,
               StandardOpenOption.SPARSE);
-      lock = file.lock().get();
-      int size = file.write(data, chunkInfo.getOffset()).get();
+
+      lock = file.lock();
+      int size = file.write(data, chunkInfo.getOffset());
       // Increment volumeIO stats here.
       volumeIOStats.incWriteTime(Time.monotonicNow() - writeTimeStart);
       volumeIOStats.incWriteOpCount();
@@ -128,6 +126,10 @@ public static void writeData(File chunkFile, ChunkInfo chunkInfo,
       }
       if (file != null) {
         try {
+          if (sync) {
+            // ensure data and metadata is persisted. Outside the lock
+            file.force(true);
+          }
           file.close();
         } catch (IOException e) {
           throw new StorageContainerException("Error closing chunk file",