HDFS-12638. Delete copy-on-truncate block along with the original block, when deleting a file being truncated. Contributed by Konstantin Shvachko.

(cherry picked from commit 60fd0d7fd73198fd610e59d1a4cd007c5fcc7205)
(cherry picked from commit 19c18f7cc90c8243af634600c4c69ec1109fcce6)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INode.java

@@ -33,9 +33,11 @@ import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.hdfs.DFSUtilClient;
+import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockStoragePolicySuite;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockUnderConstructionFeature;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.server.namenode.INodeReference.DstReference;
@@ -1051,6 +1053,18 @@ public abstract class INode implements INodeAttributes, Diff.Element<byte[]> {
       assert toDelete != null : "toDelete is null";
       toDelete.delete();
       toDeleteList.add(toDelete);
+      // If the file is being truncated
+      // the copy-on-truncate block should also be collected for deletion
+      BlockUnderConstructionFeature uc = toDelete.getUnderConstructionFeature();
+      if(uc == null) {
+        return;
+      }
+      Block truncateBlock = uc.getTruncateBlock();
+      if(truncateBlock == null || truncateBlock.equals(toDelete)) {
+        return;
+      }
+      assert truncateBlock instanceof BlockInfo : "should be BlockInfo";
+      addDeleteBlock((BlockInfo) truncateBlock);
     }
 
     public void addUpdateReplicationFactor(BlockInfo block, short targetRepl) {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFileTruncate.java

@@ -59,6 +59,7 @@ import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.StartupOption;
 import org.apache.hadoop.hdfs.server.datanode.FsDatasetTestUtils;
 import org.apache.hadoop.hdfs.server.namenode.FSDirectory.DirOp;
+import org.apache.hadoop.hdfs.tools.DFSAdmin;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.util.Time;
@@ -1153,6 +1154,46 @@ public class TestFileTruncate {
     fs.delete(parent, true);
   }
 
+  /**
+   * While rolling upgrade is in-progress the test truncates a file
+   * such that copy-on-truncate is triggered, then deletes the file,
+   * and makes sure that no blocks involved in truncate are hanging around.
+   */
+  @Test
+  public void testTruncateWithRollingUpgrade() throws Exception {
+    final DFSAdmin dfsadmin = new DFSAdmin(cluster.getConfiguration(0));
+    DistributedFileSystem dfs = cluster.getFileSystem();
+    //start rolling upgrade
+    dfs.setSafeMode(SafeModeAction.SAFEMODE_ENTER);
+    int status = dfsadmin.run(new String[]{"-rollingUpgrade", "prepare"});
+    assertEquals("could not prepare for rolling upgrade", 0, status);
+    dfs.setSafeMode(SafeModeAction.SAFEMODE_LEAVE);
+
+    Path dir = new Path("/testTruncateWithRollingUpgrade");
+    fs.mkdirs(dir);
+    final Path p = new Path(dir, "file");
+    final byte[] data = new byte[3];
+    ThreadLocalRandom.current().nextBytes(data);
+    writeContents(data, data.length, p);
+
+    assertEquals("block num should 1", 1,
+        cluster.getNamesystem().getFSDirectory().getBlockManager()
+            .getTotalBlocks());
+
+    final boolean isReady = fs.truncate(p, 2);
+    assertFalse("should be copy-on-truncate", isReady);
+    assertEquals("block num should 2", 2,
+        cluster.getNamesystem().getFSDirectory().getBlockManager()
+            .getTotalBlocks());
+    fs.delete(p, true);
+
+    assertEquals("block num should 0", 0,
+        cluster.getNamesystem().getFSDirectory().getBlockManager()
+            .getTotalBlocks());
+    status = dfsadmin.run(new String[]{"-rollingUpgrade", "finalize"});
+    assertEquals("could not finalize rolling upgrade", 0, status);
+  }
+
   static void writeContents(byte[] contents, int fileLength, Path p)
       throws IOException {
     FSDataOutputStream out = fs.create(p, true, BLOCK_SIZE, REPLICATION,