From 009295a3a69375822adafed1e993e80d45c680ce Mon Sep 17 00:00:00 2001
From: Zach York <zyork@amazon.com>
Date: Wed, 28 Feb 2018 10:40:38 -0800
Subject: [PATCH] [HBASE-20141] Fix TooManyFiles exception when
 RefreshingChannels

HBASE-19435 implements a fix for reopening file channels when they are unnexpected closed
to avoid disabling the BucketCache. However, it was missed that the the channels might not
actually be completely closed (the write or read channel might still be open
(see https://docs.oracle.com/javase/7/docs/api/java/nio/channels/ClosedChannelException.html)
This commit closes any open channels before creating a new channel.
---
 .../hadoop/hbase/io/hfile/bucket/FileIOEngine.java  | 13 +++++++++++--
 .../hbase/io/hfile/bucket/TestFileIOEngine.java     | 11 +++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/FileIOEngine.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/FileIOEngine.java
index cb454d47773..7b773bdf1c1 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/FileIOEngine.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/FileIOEngine.java
@@ -19,7 +19,6 @@
 package org.apache.hadoop.hbase.io.hfile.bucket;
 
 import java.io.File;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.nio.ByteBuffer;
@@ -234,7 +233,17 @@ public class FileIOEngine implements IOEngine {
     return fileNum;
   }
 
-  private void refreshFileConnection(int accessFileNum) throws FileNotFoundException {
+  @VisibleForTesting
+  FileChannel[] getFileChannels() {
+    return fileChannels;
+  }
+
+  @VisibleForTesting
+  void refreshFileConnection(int accessFileNum) throws IOException {
+    FileChannel fileChannel = fileChannels[accessFileNum];
+    if (fileChannel != null) {
+      fileChannel.close();
+    }
     rafs[accessFileNum] = new RandomAccessFile(filePaths[accessFileNum], "rw");
     fileChannels[accessFileNum] = rafs[accessFileNum].getChannel();
   }
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/bucket/TestFileIOEngine.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/bucket/TestFileIOEngine.java
index adf7fd0c46e..8c2bc6e03cc 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/bucket/TestFileIOEngine.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/bucket/TestFileIOEngine.java
@@ -19,10 +19,13 @@
 package org.apache.hadoop.hbase.io.hfile.bucket;
 
 import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 
 import java.io.File;
 import java.io.IOException;
 import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -129,4 +132,12 @@ public class TestFileIOEngine {
     fileIOEngine.read(ByteBuffer.wrap(data2), offset);
     assertArrayEquals(data1, data2);
   }
+
+  @Test
+  public void testRefreshFileConnectionClosesConnections() throws IOException {
+    FileChannel fileChannel = fileIOEngine.getFileChannels()[0];
+    assertNotNull(fileChannel);
+    fileIOEngine.refreshFileConnection(0);
+    assertFalse(fileChannel.isOpen());
+  }
 }