HDFS-5443. Delete 0-sized block when deleting an under-construction file that is included in snapshot. Contributed by Jing Zhao.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1539754 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -498,6 +498,9 @@ Release 2.3.0 - UNRELEASED
     HDFS-5427. Not able to read deleted files from snapshot directly under 
     snapshottable dir after checkpoint and NN restart. (Vinay via jing9)
 
+    HDFS-5443. Delete 0-sized block when deleting an under-construction file that 
+    is included in snapshot. (jing9)
+
 Release 2.2.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockInfoUnderConstruction.java

@@ -19,7 +19,6 @@ package org.apache.hadoop.hdfs.server.blockmanagement;
 
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 

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

@@ -20,6 +20,7 @@ package org.apache.hadoop.hdfs.server.namenode;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.List;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.fs.permission.PermissionStatus;
@@ -30,6 +31,7 @@ import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
 import org.apache.hadoop.hdfs.server.blockmanagement.MutableBlockCollection;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
+import org.apache.hadoop.hdfs.server.namenode.Quota.Counts;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileUnderConstructionWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 
@@ -130,6 +132,39 @@ public class INodeFileUnderConstruction extends INodeFile implements MutableBloc
     return f;
   }
   
+  @Override
+  public Quota.Counts cleanSubtree(final Snapshot snapshot, Snapshot prior,
+      final BlocksMapUpdateInfo collectedBlocks,
+      final List<INode> removedINodes, final boolean countDiffChange)
+      throws QuotaExceededException {
+    if (snapshot == null && prior != null) {
+      cleanZeroSizeBlock(collectedBlocks);
+      return Counts.newInstance();
+    } else {
+      return super.cleanSubtree(snapshot, prior, collectedBlocks,
+          removedINodes, countDiffChange);
+    }
+  }
+  
+  /**
+   * When deleting a file in the current fs directory, and the file is contained
+   * in a snapshot, we should delete the last block if it's under construction 
+   * and its size is 0.
+   */
+  private void cleanZeroSizeBlock(final BlocksMapUpdateInfo collectedBlocks) {
+    final BlockInfo[] blocks = getBlocks();
+    if (blocks != null && blocks.length > 0
+        && blocks[blocks.length - 1] instanceof BlockInfoUnderConstruction) {
+      BlockInfoUnderConstruction lastUC = 
+          (BlockInfoUnderConstruction) blocks[blocks.length - 1];
+      if (lastUC.getNumBytes() == 0) {
+        // this is a 0-sized block. do not need check its UC state here
+        collectedBlocks.addDeleteBlock(lastUC);
+        removeLastBlock(lastUC);
+      }
+    }
+  }
+  
   @Override
   public INodeFileUnderConstruction recordModification(final Snapshot latest,
       final INodeMap inodeMap) throws QuotaExceededException {
@@ -157,7 +192,7 @@ public class INodeFileUnderConstruction extends INodeFile implements MutableBloc
    * Remove a block from the block list. This block should be
    * the last one on the list.
    */
-  boolean removeLastBlock(Block oldblock) throws IOException {
+  boolean removeLastBlock(Block oldblock) {
     final BlockInfo[] blocks = getBlocks();
     if (blocks == null || blocks.length == 0) {
       return false;

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

@@ -32,6 +32,7 @@ import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
 import org.apache.hadoop.hdfs.server.namenode.FSDirectory;
@@ -274,4 +275,76 @@ public class TestSnapshotBlocksMap {
         "s2/bar");
     DFSTestUtil.readFile(hdfs, new Path(bar2SnapshotPath));
   }
+
+  /**
+   * Make sure we delete 0-sized block when deleting an INodeFileUCWithSnapshot
+   */
+  @Test
+  public void testDeletionWithZeroSizeBlock() throws Exception {
+    final Path foo = new Path("/foo");
+    final Path bar = new Path(foo, "bar");
+    DFSTestUtil.createFile(hdfs, bar, BLOCKSIZE, REPLICATION, 0L);
+
+    SnapshotTestHelper.createSnapshot(hdfs, foo, "s0");
+    hdfs.append(bar);
+
+    INodeFile barNode = fsdir.getINode4Write(bar.toString()).asFile();
+    BlockInfo[] blks = barNode.getBlocks();
+    assertEquals(1, blks.length);
+    assertEquals(BLOCKSIZE, blks[0].getNumBytes());
+    ExtendedBlock previous = new ExtendedBlock(fsn.getBlockPoolId(), blks[0]);
+    cluster.getNameNodeRpc()
+        .addBlock(bar.toString(), hdfs.getClient().getClientName(), previous,
+            null, barNode.getId(), null);
+
+    SnapshotTestHelper.createSnapshot(hdfs, foo, "s1");
+
+    barNode = fsdir.getINode4Write(bar.toString()).asFile();
+    blks = barNode.getBlocks();
+    assertEquals(2, blks.length);
+    assertEquals(BLOCKSIZE, blks[0].getNumBytes());
+    assertEquals(0, blks[1].getNumBytes());
+
+    hdfs.delete(bar, true);
+    final Path sbar = SnapshotTestHelper.getSnapshotPath(foo, "s1",
+        bar.getName());
+    barNode = fsdir.getINode(sbar.toString()).asFile();
+    blks = barNode.getBlocks();
+    assertEquals(1, blks.length);
+    assertEquals(BLOCKSIZE, blks[0].getNumBytes());
+  }
+
+  /** Make sure we delete 0-sized block when deleting an INodeFileUC */
+  @Test
+  public void testDeletionWithZeroSizeBlock2() throws Exception {
+    final Path foo = new Path("/foo");
+    final Path subDir = new Path(foo, "sub");
+    final Path bar = new Path(subDir, "bar");
+    DFSTestUtil.createFile(hdfs, bar, BLOCKSIZE, REPLICATION, 0L);
+
+    hdfs.append(bar);
+
+    INodeFile barNode = fsdir.getINode4Write(bar.toString()).asFile();
+    BlockInfo[] blks = barNode.getBlocks();
+    assertEquals(1, blks.length);
+    ExtendedBlock previous = new ExtendedBlock(fsn.getBlockPoolId(), blks[0]);
+    cluster.getNameNodeRpc()
+        .addBlock(bar.toString(), hdfs.getClient().getClientName(), previous,
+            null, barNode.getId(), null);
+
+    SnapshotTestHelper.createSnapshot(hdfs, foo, "s1");
+
+    barNode = fsdir.getINode4Write(bar.toString()).asFile();
+    blks = barNode.getBlocks();
+    assertEquals(2, blks.length);
+    assertEquals(BLOCKSIZE, blks[0].getNumBytes());
+    assertEquals(0, blks[1].getNumBytes());
+
+    hdfs.delete(subDir, true);
+    final Path sbar = SnapshotTestHelper.getSnapshotPath(foo, "s1", "sub/bar");
+    barNode = fsdir.getINode(sbar.toString()).asFile();
+    blks = barNode.getBlocks();
+    assertEquals(1, blks.length);
+    assertEquals(BLOCKSIZE, blks[0].getNumBytes());
+  }
 }