From e2278f9544380ec7abc92c3592bbe2068e62cb45 Mon Sep 17 00:00:00 2001
From: tedyu <yuzhihong@gmail.com>
Date: Wed, 12 Oct 2016 19:42:18 -0700
Subject: [PATCH] HBASE-16716 OfflineMetaRepair leaves empty directory inside
 /hbase/WALs which remains forever (Pankaj Kumar)

---
 .../apache/hadoop/hbase/util/HBaseFsck.java   | 21 +++++++++++++++
 .../util/hbck/TestOfflineMetaRebuildBase.java | 26 +++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/util/HBaseFsck.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/util/HBaseFsck.java
index 745adbf0bf1..458230f4069 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/util/HBaseFsck.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/util/HBaseFsck.java
@@ -115,6 +115,7 @@ import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
 import org.apache.hadoop.hbase.regionserver.HRegion;
 import org.apache.hadoop.hbase.regionserver.HRegionFileSystem;
 import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
+import org.apache.hadoop.hbase.regionserver.wal.FSHLog;
 import org.apache.hadoop.hbase.security.AccessDeniedException;
 import org.apache.hadoop.hbase.security.UserProvider;
 import org.apache.hadoop.hbase.util.Bytes.ByteArrayComparator;
@@ -1524,11 +1525,31 @@ public class HBaseFsck extends Configured implements Closeable {
     }
     meta.batchMutate(puts.toArray(new Put[puts.size()]));
     HRegion.closeHRegion(meta);
+    // clean up the temporary hbck meta recovery WAL directory
+    removeHBCKMetaRecoveryWALDir(meta);
     LOG.info("Success! hbase:meta table rebuilt.");
     LOG.info("Old hbase:meta is moved into " + backupDir);
     return true;
   }
 
+  /**
+   * Removes the empty Meta recovery WAL directory.
+   * @param meta Meta region
+   */
+  private void removeHBCKMetaRecoveryWALDir(HRegion meta) throws IOException {
+    // TODO Since HBASE-11983 not available in this branch, so we don't know the walFactoryId.
+    // Retrieving WAL directory
+    Path walLogDir = ((FSHLog) meta.getWAL()).getCurrentFileName().getParent();
+    FileSystem fs = FSUtils.getCurrentFileSystem(getConf());
+    FileStatus[] walFiles = FSUtils.listStatus(fs, walLogDir, null);
+    if (walFiles == null || walFiles.length == 0) {
+      LOG.info("HBCK meta recovery WAL directory is empty, removing it now.");
+      if (!FSUtils.deleteDirectory(fs, walLogDir)) {
+        LOG.warn("Couldn't clear the HBCK Meta recovery WAL directory " + walLogDir);
+      }
+    }
+  }
+
   /**
    * Log an appropriate message about whether or not overlapping merges are computed in parallel.
    */
diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/util/hbck/TestOfflineMetaRebuildBase.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/util/hbck/TestOfflineMetaRebuildBase.java
index 43b1444294a..b31e20e2970 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/util/hbck/TestOfflineMetaRebuildBase.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/util/hbck/TestOfflineMetaRebuildBase.java
@@ -20,17 +20,24 @@ package org.apache.hadoop.hbase.util.hbck;
 import static org.apache.hadoop.hbase.util.hbck.HbckTestingUtil.assertErrors;
 import static org.apache.hadoop.hbase.util.hbck.HbckTestingUtil.doFsck;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
+import java.io.IOException;
 import java.util.Arrays;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.fs.FileStatus;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.HTableDescriptor;
 import org.apache.hadoop.hbase.testclassification.MediumTests;
 import org.apache.hadoop.hbase.client.Admin;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.ConnectionFactory;
+import org.apache.hadoop.hbase.util.FSUtils;
 import org.apache.hadoop.hbase.util.HBaseFsck;
 import org.apache.hadoop.hbase.util.HBaseFsck.ErrorReporter.ERROR_CODE;
 import org.junit.Test;
@@ -65,6 +72,7 @@ public class TestOfflineMetaRebuildBase extends OfflineMetaRebuildTestCore {
     // rebuild meta table from scratch
     HBaseFsck fsck = new HBaseFsck(conf);
     assertTrue(fsck.rebuildMeta(false));
+    assertTrue("HBCK meta recovery WAL directory exist.", validateHBCKMetaRecoveryWALDir());
 
     // bring up the minicluster
     TEST_UTIL.startMiniZKCluster();
@@ -87,4 +95,22 @@ public class TestOfflineMetaRebuildBase extends OfflineMetaRebuildTestCore {
     LOG.info("Table " + table + " has " + tableRowCount(conf, table) + " entries.");
     assertEquals(16, tableRowCount(conf, table));
   }
+
+  /**
+   * Validate whether Meta recovery empty WAL directory is removed.
+   * @return True if directory is removed otherwise false.
+   */
+  private boolean validateHBCKMetaRecoveryWALDir() throws IOException {
+    Path rootdir = FSUtils.getRootDir(TEST_UTIL.getConfiguration());
+    Path walLogDir = new Path(rootdir, HConstants.HREGION_LOGDIR_NAME);
+    FileSystem fs = TEST_UTIL.getTestFileSystem();
+    FileStatus[] walFiles = FSUtils.listStatus(fs, walLogDir, null);
+    assertNotNull(walFiles);
+    for (FileStatus fsStat : walFiles) {
+      if (fsStat.isDirectory() && fsStat.getPath().getName().startsWith("hregion-")) {
+        return false;
+      }
+    }
+    return true;
+  }
 }