From 6828337d855abe8564ece2266ace7cfc51ee16ec Mon Sep 17 00:00:00 2001
From: Daryn Sharp <daryn@apache.org>
Date: Thu, 5 Dec 2013 15:28:12 +0000
Subject: [PATCH] HDFS-5514. FSNamesystem's fsLock should allow custom
 implementation (daryn)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1548161 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  2 ++
 .../hdfs/server/namenode/FSNamesystem.java    |  8 ++---
 .../server/namenode/TestFSNamesystem.java     | 36 +++++++++++++++++++
 3 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index d7ff8fb7a7..379b01af43 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -457,6 +457,8 @@ Release 2.4.0 - UNRELEASED
     HDFS-5444. Choose default web UI based on browser capabilities. (Haohui Mai
     via jing9)
 
+    HDFS-5514. FSNamesystem's fsLock should allow custom implementation (daryn)
+
   IMPROVEMENTS
 
     HDFS-5267. Remove volatile from LightWeightHashSet. (Junping Du via llu)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
index 0cae09863b..6a74b49fa5 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
@@ -467,7 +467,7 @@ private void logAuditEvent(boolean succeeded,
   private final long accessTimePrecision;
 
   /** Lock to protect FSNamesystem. */
-  private ReentrantReadWriteLock fsLock;
+  private FSNamesystemLock fsLock;
 
   /**
    * Used when this NN is in standby state to read from the shared edit log.
@@ -650,7 +650,7 @@ public static FSNamesystem loadFromDisk(Configuration conf)
       throws IOException {
     boolean fair = conf.getBoolean("dfs.namenode.fslock.fair", true);
     LOG.info("fsLock is fair:" + fair);
-    fsLock = new ReentrantReadWriteLock(fair);
+    fsLock = new FSNamesystemLock(fair);
     try {
       resourceRecheckInterval = conf.getLong(
           DFS_NAMENODE_RESOURCE_CHECK_INTERVAL_KEY,
@@ -6771,12 +6771,12 @@ public void setEditLogTailerForTests(EditLogTailer tailer) {
   
   @VisibleForTesting
   void setFsLockForTests(ReentrantReadWriteLock lock) {
-    this.fsLock = lock;
+    this.fsLock.coarseLock = lock;
   }
   
   @VisibleForTesting
   ReentrantReadWriteLock getFsLockForTests() {
-    return fsLock;
+    return fsLock.coarseLock;
   }
 
   @VisibleForTesting
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFSNamesystem.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFSNamesystem.java
index a2bd172d5e..3af20a7303 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFSNamesystem.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFSNamesystem.java
@@ -158,4 +158,40 @@ public void testFsLockFairness() throws IOException, InterruptedException{
     fsNamesystem = new FSNamesystem(conf, fsImage);
     assertFalse(fsNamesystem.getFsLockForTests().isFair());
   }  
+  
+  @Test
+  public void testFSNamesystemLockCompatibility() {
+    FSNamesystemLock rwLock = new FSNamesystemLock(true);
+
+    assertEquals(0, rwLock.getReadHoldCount());
+    rwLock.readLock().lock();
+    assertEquals(1, rwLock.getReadHoldCount());
+
+    rwLock.readLock().lock();
+    assertEquals(2, rwLock.getReadHoldCount());
+
+    rwLock.readLock().unlock();
+    assertEquals(1, rwLock.getReadHoldCount());
+
+    rwLock.readLock().unlock();
+    assertEquals(0, rwLock.getReadHoldCount());
+
+    assertFalse(rwLock.isWriteLockedByCurrentThread());
+    assertEquals(0, rwLock.getWriteHoldCount());
+    rwLock.writeLock().lock();
+    assertTrue(rwLock.isWriteLockedByCurrentThread());
+    assertEquals(1, rwLock.getWriteHoldCount());
+    
+    rwLock.writeLock().lock();
+    assertTrue(rwLock.isWriteLockedByCurrentThread());
+    assertEquals(2, rwLock.getWriteHoldCount());
+
+    rwLock.writeLock().unlock();
+    assertTrue(rwLock.isWriteLockedByCurrentThread());
+    assertEquals(1, rwLock.getWriteHoldCount());
+
+    rwLock.writeLock().unlock();
+    assertFalse(rwLock.isWriteLockedByCurrentThread());
+    assertEquals(0, rwLock.getWriteHoldCount());
+  }
 }