HDFS-7106. Reconfiguring DataNode volumes does not release the lock files in removed volumes. (cnauroth via cmccabe)

(cherry picked from commit 912ad32b03c1e023ab88918bfa8cb356d1851545)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -447,6 +447,9 @@ Release 2.6.0 - UNRELEASED
 
     HDFS-7046. HA NN can NPE upon transition to active. (kihwal)
 
+    HDFS-7106. Reconfiguring DataNode volumes does not release the lock files
+    in removed volumes. (cnauroth via cmccabe)
+
     BREAKDOWN OF HDFS-6134 AND HADOOP-10150 SUBTASKS AND RELATED JIRAS
   
       HDFS-6387. HDFS CLI admin tool for creating & deleting an

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataStorage.java

@@ -362,6 +362,13 @@ public class DataStorage extends Storage {
       StorageDirectory sd = it.next();
       if (dataDirs.contains(sd.getRoot())) {
         it.remove();
+        try {
+          sd.unlock();
+        } catch (IOException e) {
+          LOG.warn(String.format(
+            "I/O error attempting to unlock storage directory %s.",
+            sd.getRoot()), e);
+        }
       }
     }
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeHotSwapVolumes.java

@@ -31,13 +31,19 @@ import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.MiniDFSNNTopology;
 import org.apache.hadoop.hdfs.protocol.BlockListAsLongs;
+import org.apache.hadoop.hdfs.server.common.Storage;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
+import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.After;
 import org.junit.Test;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.channels.OverlappingFileLockException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -46,13 +52,19 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeoutException;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 public class TestDataNodeHotSwapVolumes {
+  private static final Log LOG = LogFactory.getLog(
+    TestDataNodeHotSwapVolumes.class);
   private static final int BLOCK_SIZE = 512;
   private MiniDFSCluster cluster;
 
@@ -179,8 +191,10 @@ public class TestDataNodeHotSwapVolumes {
     DataNode.ChangedVolumes changedVolumes =dn.parseChangedVolumes();
     List<StorageLocation> newVolumes = changedVolumes.newLocations;
     assertEquals(2, newVolumes.size());
-    assertEquals("/foo/path1", newVolumes.get(0).getFile().getAbsolutePath());
-    assertEquals("/foo/path2", newVolumes.get(1).getFile().getAbsolutePath());
+    assertEquals(new File("/foo/path1").getAbsolutePath(),
+      newVolumes.get(0).getFile().getAbsolutePath());
+    assertEquals(new File("/foo/path2").getAbsolutePath(),
+      newVolumes.get(1).getFile().getAbsolutePath());
 
     List<StorageLocation> removedVolumes = changedVolumes.deactivateLocations;
     assertEquals(oldLocations.size(), removedVolumes.size());
@@ -371,6 +385,8 @@ public class TestDataNodeHotSwapVolumes {
     String newDirs = oldDirs.iterator().next();  // Keep the first volume.
     dn.reconfigurePropertyImpl(
         DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY, newDirs);
+    assertFileLocksReleased(
+      new ArrayList<String>(oldDirs).subList(1, oldDirs.size()));
     dn.scheduleAllBlockReport(0);
 
     try {
@@ -409,6 +425,8 @@ public class TestDataNodeHotSwapVolumes {
     String newDirs = oldDirs.iterator().next();  // Keep the first volume.
     dn.reconfigurePropertyImpl(
         DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY, newDirs);
+    assertFileLocksReleased(
+      new ArrayList<String>(oldDirs).subList(1, oldDirs.size()));
 
     // Force DataNode to report missing blocks.
     dn.scheduleAllBlockReport(0);
@@ -420,4 +438,44 @@ public class TestDataNodeHotSwapVolumes {
     // Wait NameNode to replica missing blocks.
     DFSTestUtil.waitReplication(fs, testFile, replFactor);
   }
-}
+
+  /**
+   * Asserts that the storage lock file in each given directory has been
+   * released.  This method works by trying to acquire the lock file itself.  If
+   * locking fails here, then the main code must have failed to release it.
+   *
+   * @param dirs every storage directory to check
+   * @throws IOException if there is an unexpected I/O error
+   */
+  private static void assertFileLocksReleased(Collection<String> dirs)
+      throws IOException {
+    for (String dir: dirs) {
+      StorageLocation sl = StorageLocation.parse(dir);
+      File lockFile = new File(sl.getFile(), Storage.STORAGE_FILE_LOCK);
+      RandomAccessFile raf = null;
+      FileChannel channel = null;
+      FileLock lock = null;
+      try {
+        raf = new RandomAccessFile(lockFile, "rws");
+        channel = raf.getChannel();
+        lock = channel.tryLock();
+        assertNotNull(String.format(
+          "Lock file at %s appears to be held by a different process.",
+          lockFile.getAbsolutePath()), lock);
+      } catch (OverlappingFileLockException e) {
+        fail(String.format("Must release lock file at %s.",
+          lockFile.getAbsolutePath()));
+      } finally {
+        if (lock != null) {
+          try {
+            lock.release();
+          } catch (IOException e) {
+            LOG.warn(String.format("I/O error releasing file lock %s.",
+              lockFile.getAbsolutePath()), e);
+          }
+        }
+        IOUtils.cleanup(null, channel, raf);
+      }
+    }
+  }
+}