HBASE-16716 OfflineMetaRepair leaves empty directory inside /hbase/WALs which remains forever (Pankaj Kumar)

hbase-server/src/main/java/org/apache/hadoop/hbase/util/HBaseFsck.java

@@ -1388,10 +1388,11 @@ public class HBaseFsck extends Configured implements Closeable {
   /**
    * This borrows code from MasterFileSystem.bootstrap(). Explicitly creates it's own WAL, so be
    * sure to close it as well as the region when you're finished.
-   *
+   * @param walFactoryID A unique identifier for WAL factory. Filesystem implementations will use
+   *          this ID to make a directory inside WAL directory path.
    * @return an open hbase:meta HRegion
    */
-  private HRegion createNewMeta() throws IOException {
+  private HRegion createNewMeta(String walFactoryID) throws IOException {
     Path rootdir = FSUtils.getRootDir(getConf());
     Configuration c = getConf();
     HRegionInfo metaHRI = new HRegionInfo(HRegionInfo.FIRST_META_REGIONINFO);
@@ -1402,9 +1403,8 @@ public class HBaseFsck extends Configured implements Closeable {
     Configuration confForWAL = new Configuration(c);
     confForWAL.set(HConstants.HBASE_DIR, rootdir.toString());
     WAL wal = (new WALFactory(confForWAL,
-        Collections.<WALActionsListener>singletonList(new MetricsWAL()),
+        Collections.<WALActionsListener> singletonList(new MetricsWAL()), walFactoryID))
-        "hbck-meta-recovery-" + RandomStringUtils.randomNumeric(8))).
+            .getWAL(metaHRI.getEncodedNameAsBytes(), metaHRI.getTable().getNamespace());
-        getWAL(metaHRI.getEncodedNameAsBytes(), metaHRI.getTable().getNamespace());
     HRegion meta = HRegion.createHRegion(metaHRI, rootdir, c, metaDescriptor, wal);
     MasterFileSystem.setInfoFamilyCachingForMeta(metaDescriptor, true);
     return meta;
@@ -1513,7 +1513,8 @@ public class HBaseFsck extends Configured implements Closeable {
     Path backupDir = sidelineOldMeta();
 
     LOG.info("Creating new hbase:meta");
-    HRegion meta = createNewMeta();
+    String walFactoryId = "hbck-meta-recovery-" + RandomStringUtils.randomNumeric(8);
+    HRegion meta = createNewMeta(walFactoryId);
 
     // populate meta
     List<Put> puts = generatePuts(tablesInfo);
@@ -1527,11 +1528,31 @@ public class HBaseFsck extends Configured implements Closeable {
     if (meta.getWAL() != null) {
       meta.getWAL().close();
     }
+    // clean up the temporary hbck meta recovery WAL directory
+    removeHBCKMetaRecoveryWALDir(walFactoryId);
     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 walFactoryID A unique identifier for WAL factory which was used by Filesystem to make a
+   *          Meta recovery WAL directory inside WAL directory path.
+   */
+  private void removeHBCKMetaRecoveryWALDir(String walFactoryId) throws IOException {
+    Path rootdir = FSUtils.getRootDir(getConf());
+    Path walLogDir = new Path(new Path(rootdir, HConstants.HREGION_LOGDIR_NAME), walFactoryId);
+    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.
    */

hbase-server/src/test/java/org/apache/hadoop/hbase/util/hbck/TestOfflineMetaRebuildBase.java

@@ -23,10 +23,15 @@ 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.TableName;
 import org.apache.hadoop.hbase.client.Admin;
@@ -34,6 +39,7 @@ import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.ConnectionFactory;
 import org.apache.hadoop.hbase.testclassification.MediumTests;
 import org.apache.hadoop.hbase.testclassification.MiscTests;
+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;
@@ -68,6 +74,7 @@ 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();
@@ -97,4 +104,22 @@ 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("hbck-meta-recovery-")) {
+        return false;
+      }
+    }
+    return true;
+  }
 }