HDFS-5285. Flatten INodeFile hierarchy: Replace INodeFileUnderConstruction and INodeFileUnderConstructionWithSnapshot with FileUnderContructionFeature. Contributed by jing9

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1544389 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -213,6 +213,10 @@ Trunk (Unreleased)
     HDFS-5473. Consistent naming of user-visible caching classes and methods
     (cmccabe)
 
+    HDFS-5285. Flatten INodeFile hierarchy: Replace INodeFileUnderConstruction
+    and INodeFileUnderConstructionWithSnapshot with FileUnderContructionFeature.
+    (jing9 via szetszwo)
+
   OPTIMIZATIONS
     HDFS-5349. DNA_CACHE and DNA_UNCACHE should be by blockId only. (cmccabe)
 

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

@@ -64,4 +64,21 @@ public interface BlockCollection {
    * Get the name of the collection.
    */
   public String getName();
+
+  /**
+   * Set the block at the given index.
+   */
+  public void setBlock(int index, BlockInfo blk);
+
+  /**
+   * Convert the last block of the collection to an under-construction block
+   * and set the locations.
+   */
+  public BlockInfoUnderConstruction setLastBlock(BlockInfo lastBlock,
+      DatanodeDescriptor[] locations) throws IOException;
+
+  /**
+   * @return whether the block collection is under construction.
+   */
+  public boolean isUnderConstruction();
 }

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

@@ -560,7 +560,7 @@ public class BlockManager {
    * @throws IOException if the block does not have at least a minimal number
    * of replicas reported from data-nodes.
    */
-  public boolean commitOrCompleteLastBlock(MutableBlockCollection bc, 
+  public boolean commitOrCompleteLastBlock(BlockCollection bc,
       Block commitBlock) throws IOException {
     if(commitBlock == null)
       return false; // not committing, this is a block allocation retry
@@ -583,7 +583,7 @@ public class BlockManager {
    * @throws IOException if the block does not have at least a minimal number
    * of replicas reported from data-nodes.
    */
-  private BlockInfo completeBlock(final MutableBlockCollection bc,
+  private BlockInfo completeBlock(final BlockCollection bc,
       final int blkIndex, boolean force) throws IOException {
     if(blkIndex < 0)
       return null;
@@ -616,7 +616,7 @@ public class BlockManager {
     return blocksMap.replaceBlock(completeBlock);
   }
 
-  private BlockInfo completeBlock(final MutableBlockCollection bc,
+  private BlockInfo completeBlock(final BlockCollection bc,
       final BlockInfo block, boolean force) throws IOException {
     BlockInfo[] fileBlocks = bc.getBlocks();
     for(int idx = 0; idx < fileBlocks.length; idx++)
@@ -631,7 +631,7 @@ public class BlockManager {
    * regardless of whether enough replicas are present. This is necessary
    * when tailing edit logs as a Standby.
    */
-  public BlockInfo forceCompleteBlock(final MutableBlockCollection bc,
+  public BlockInfo forceCompleteBlock(final BlockCollection bc,
       final BlockInfoUnderConstruction block) throws IOException {
     block.commitBlock(block);
     return completeBlock(bc, block, true);
@@ -652,7 +652,7 @@ public class BlockManager {
    * @return the last block locations if the block is partial or null otherwise
    */
   public LocatedBlock convertLastBlockToUnderConstruction(
-      MutableBlockCollection bc) throws IOException {
+      BlockCollection bc) throws IOException {
     BlockInfo oldBlock = bc.getLastBlock();
     if(oldBlock == null ||
         bc.getPreferredBlockSize() == oldBlock.getNumBytes())
@@ -1209,7 +1209,7 @@ public class BlockManager {
             // block should belong to a file
             bc = blocksMap.getBlockCollection(block);
             // abandoned block or block reopened for append
-            if(bc == null || bc instanceof MutableBlockCollection) {
+            if(bc == null || bc.isUnderConstruction()) {
               neededReplications.remove(block, priority); // remove from neededReplications
               continue;
             }
@@ -1290,7 +1290,7 @@ public class BlockManager {
           // block should belong to a file
           bc = blocksMap.getBlockCollection(block);
           // abandoned block or block reopened for append
-          if(bc == null || bc instanceof MutableBlockCollection) {
+          if(bc == null || bc.isUnderConstruction()) {
             neededReplications.remove(block, priority); // remove from neededReplications
             rw.targets = null;
             continue;
@@ -2145,7 +2145,7 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
     int numCurrentReplica = countLiveNodes(storedBlock);
     if (storedBlock.getBlockUCState() == BlockUCState.COMMITTED
         && numCurrentReplica >= minReplication) {
-      completeBlock((MutableBlockCollection)storedBlock.getBlockCollection(), storedBlock, false);
+      completeBlock(storedBlock.getBlockCollection(), storedBlock, false);
     } else if (storedBlock.isComplete()) {
       // check whether safe replication is reached for the block
       // only complete blocks are counted towards that.
@@ -2215,7 +2215,7 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
 
     if(storedBlock.getBlockUCState() == BlockUCState.COMMITTED &&
         numLiveReplicas >= minReplication) {
-      storedBlock = completeBlock((MutableBlockCollection)bc, storedBlock, false);
+      storedBlock = completeBlock(bc, storedBlock, false);
     } else if (storedBlock.isComplete()) {
       // check whether safe replication is reached for the block
       // only complete blocks are counted towards that
@@ -2226,7 +2226,7 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
     }
     
     // if file is under construction, then done for now
-    if (bc instanceof MutableBlockCollection) {
+    if (bc.isUnderConstruction()) {
       return storedBlock;
     }
 
@@ -2835,7 +2835,7 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
         + ", corrupt replicas: " + num.corruptReplicas()
         + ", decommissioned replicas: " + num.decommissionedReplicas()
         + ", excess replicas: " + num.excessReplicas()
-        + ", Is Open File: " + (bc instanceof MutableBlockCollection)
+        + ", Is Open File: " + bc.isUnderConstruction()
         + ", Datanodes having this block: " + nodeList + ", Current Datanode: "
         + srcNode + ", Is current datanode decommissioning: "
         + srcNode.isDecommissionInProgress());
@@ -2894,7 +2894,7 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
             if ((curReplicas == 0) && (num.decommissionedReplicas() > 0)) {
               decommissionOnlyReplicas++;
             }
-            if (bc instanceof MutableBlockCollection) {
+            if (bc.isUnderConstruction()) {
               underReplicatedInOpenFiles++;
             }
           }

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

@@ -276,13 +276,9 @@ public class FSDirectory implements Closeable {
    * @throws UnresolvedLinkException
    * @throws SnapshotAccessControlException 
    */
-  INodeFileUnderConstruction addFile(String path, 
-                PermissionStatus permissions,
-                short replication,
-                long preferredBlockSize,
-                String clientName,
-                String clientMachine,
-                DatanodeDescriptor clientNode)
+  INodeFile addFile(String path, PermissionStatus permissions,
+      short replication, long preferredBlockSize, String clientName,
+      String clientMachine, DatanodeDescriptor clientNode)
     throws FileAlreadyExistsException, QuotaExceededException,
       UnresolvedLinkException, SnapshotAccessControlException {
     waitForReady();
@@ -300,11 +296,11 @@ public class FSDirectory implements Closeable {
     if (!mkdirs(parent.toString(), permissions, true, modTime)) {
       return null;
     }
-    INodeFileUnderConstruction newNode = new INodeFileUnderConstruction(
-                                 namesystem.allocateNewInodeId(),
-                                 permissions,replication,
-                                 preferredBlockSize, modTime, clientName, 
-                                 clientMachine, clientNode);
+    INodeFile newNode = new INodeFile(namesystem.allocateNewInodeId(), null,
+        permissions, modTime, modTime, BlockInfo.EMPTY_ARRAY, replication,
+        preferredBlockSize);
+    newNode.toUnderConstruction(clientName, clientMachine, clientNode);
+
     boolean added = false;
     writeLock();
     try {
@@ -336,8 +332,11 @@ public class FSDirectory implements Closeable {
     final INodeFile newNode;
     assert hasWriteLock();
     if (underConstruction) {
-      newNode = new INodeFileUnderConstruction(id, permissions, replication,
-          preferredBlockSize, modificationTime, clientName, clientMachine, null);
+      newNode = new INodeFile(id, null, permissions, modificationTime,
+          modificationTime, BlockInfo.EMPTY_ARRAY, replication,
+          preferredBlockSize);
+      newNode.toUnderConstruction(clientName, clientMachine, null);
+
     } else {
       newNode = new INodeFile(id, null, permissions, modificationTime, atime,
           BlockInfo.EMPTY_ARRAY, replication, preferredBlockSize);
@@ -366,8 +365,8 @@ public class FSDirectory implements Closeable {
 
     writeLock();
     try {
-      final INodeFileUnderConstruction fileINode = 
-          INodeFileUnderConstruction.valueOf(inodesInPath.getLastINode(), path);
+      final INodeFile fileINode = inodesInPath.getLastINode().asFile();
+      Preconditions.checkState(fileINode.isUnderConstruction());
 
       // check quota limits and updated space consumed
       updateCount(inodesInPath, 0, fileINode.getBlockDiskspace(), true);
@@ -397,8 +396,8 @@ public class FSDirectory implements Closeable {
   /**
    * Persist the block list for the inode.
    */
-  void persistBlocks(String path, INodeFileUnderConstruction file,
-      boolean logRetryCache) {
+  void persistBlocks(String path, INodeFile file, boolean logRetryCache) {
+    Preconditions.checkArgument(file.isUnderConstruction());
     waitForReady();
 
     writeLock();
@@ -437,8 +436,9 @@ public class FSDirectory implements Closeable {
    * Remove a block from the file.
    * @return Whether the block exists in the corresponding file
    */
-  boolean removeBlock(String path, INodeFileUnderConstruction fileNode,
-                      Block block) throws IOException {
+  boolean removeBlock(String path, INodeFile fileNode, Block block)
+      throws IOException {
+    Preconditions.checkArgument(fileNode.isUnderConstruction());
     waitForReady();
 
     writeLock();
@@ -450,7 +450,8 @@ public class FSDirectory implements Closeable {
   }
   
   boolean unprotectedRemoveBlock(String path,
-      INodeFileUnderConstruction fileNode, Block block) throws IOException {
+      INodeFile fileNode, Block block) throws IOException {
+    Preconditions.checkArgument(fileNode.isUnderConstruction());
     // modify file-> block and blocksMap
     boolean removed = fileNode.removeLastBlock(block);
     if (!removed) {
@@ -1477,38 +1478,6 @@ public class FSDirectory implements Closeable {
     }
   }
 
-  /**
-   * Replaces the specified INodeFile with the specified one.
-   */
-  void replaceINodeFile(String path, INodeFile oldnode,
-      INodeFile newnode) throws IOException {
-    writeLock();
-    try {
-      unprotectedReplaceINodeFile(path, oldnode, newnode);
-    } finally {
-      writeUnlock();
-    }
-  }
-
-  /** Replace an INodeFile and record modification for the latest snapshot. */
-  void unprotectedReplaceINodeFile(final String path, final INodeFile oldnode,
-      final INodeFile newnode) {
-    Preconditions.checkState(hasWriteLock());
-
-    oldnode.getParent().replaceChild(oldnode, newnode, inodeMap);
-    oldnode.clear();
-
-    /* Currently oldnode and newnode are assumed to contain the same
-     * blocks. Otherwise, blocks need to be removed from the blocksMap.
-     */
-    int index = 0;
-    for (BlockInfo b : newnode.getBlocks()) {
-      BlockInfo info = getBlockManager().addBlockCollection(b, newnode);
-      newnode.setBlock(index, info); // inode refers to the block in BlocksMap
-      index++;
-    }
-  }
-
   /**
    * Get a partial listing of the indicated directory
    *

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

@@ -680,8 +680,8 @@ public class FSEditLog implements LogsPurgeable {
    * Add open lease record to edit log. 
    * Records the block locations of the last block.
    */
-  public void logOpenFile(String path, INodeFileUnderConstruction newNode,
-      boolean toLogRpcIds) {
+  public void logOpenFile(String path, INodeFile newNode, boolean toLogRpcIds) {
+    Preconditions.checkArgument(newNode.isUnderConstruction());
     AddOp op = AddOp.getInstance(cache.get())
       .setInodeId(newNode.getId())
       .setPath(path)
@@ -691,8 +691,8 @@ public class FSEditLog implements LogsPurgeable {
       .setBlockSize(newNode.getPreferredBlockSize())
       .setBlocks(newNode.getBlocks())
       .setPermissionStatus(newNode.getPermissionStatus())
-      .setClientName(newNode.getClientName())
-      .setClientMachine(newNode.getClientMachine());
+      .setClientName(newNode.getFileUnderConstructionFeature().getClientName())
+      .setClientMachine(newNode.getFileUnderConstructionFeature().getClientMachine());
     logRpcIds(op, toLogRpcIds);
     logEdit(op);
   }
@@ -713,8 +713,8 @@ public class FSEditLog implements LogsPurgeable {
     logEdit(op);
   }
   
-  public void logUpdateBlocks(String path, INodeFileUnderConstruction file,
-      boolean toLogRpcIds) {
+  public void logUpdateBlocks(String path, INodeFile file, boolean toLogRpcIds) {
+    Preconditions.checkArgument(file.isUnderConstruction());
     UpdateBlocksOp op = UpdateBlocksOp.getInstance(cache.get())
       .setPath(path)
       .setBlocks(file.getBlocks());

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

@@ -85,6 +85,7 @@ import org.apache.hadoop.hdfs.util.ChunkedArrayList;
 import org.apache.hadoop.hdfs.util.Holder;
 
 import com.google.common.base.Joiner;
+import com.google.common.base.Preconditions;
 
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
@@ -369,15 +370,15 @@ public class FSEditLogLoader {
       }
 
       final INodesInPath iip = fsDir.getLastINodeInPath(addCloseOp.path);
-      final INodeFile oldFile = INodeFile.valueOf(iip.getINode(0), addCloseOp.path);
+      final INodeFile file = INodeFile.valueOf(iip.getINode(0), addCloseOp.path);
 
       // Update the salient file attributes.
-      oldFile.setAccessTime(addCloseOp.atime, null, fsDir.getINodeMap());
-      oldFile.setModificationTime(addCloseOp.mtime, null, fsDir.getINodeMap());
-      updateBlocks(fsDir, addCloseOp, oldFile);
+      file.setAccessTime(addCloseOp.atime, null, fsDir.getINodeMap());
+      file.setModificationTime(addCloseOp.mtime, null, fsDir.getINodeMap());
+      updateBlocks(fsDir, addCloseOp, file);
 
       // Now close the file
-      if (!oldFile.isUnderConstruction() &&
+      if (!file.isUnderConstruction() &&
           logVersion <= LayoutVersion.BUGFIX_HDFS_2991_VERSION) {
         // There was a bug (HDFS-2991) in hadoop < 0.23.1 where OP_CLOSE
         // could show up twice in a row. But after that version, this
@@ -387,11 +388,9 @@ public class FSEditLogLoader {
       }
       // One might expect that you could use removeLease(holder, path) here,
       // but OP_CLOSE doesn't serialize the holder. So, remove by path.
-      if (oldFile.isUnderConstruction()) {
-        INodeFileUnderConstruction ucFile = (INodeFileUnderConstruction) oldFile;
+      if (file.isUnderConstruction()) {
         fsNamesys.leaseManager.removeLeaseWithPrefixPath(addCloseOp.path);
-        INodeFile newFile = ucFile.toINodeFile(ucFile.getModificationTime());
-        fsDir.unprotectedReplaceINodeFile(addCloseOp.path, ucFile, newFile);
+        file.toCompleteFile(file.getModificationTime());
       }
       break;
     }
@@ -564,9 +563,8 @@ public class FSEditLogLoader {
 
       Lease lease = fsNamesys.leaseManager.getLease(
           reassignLeaseOp.leaseHolder);
-      INodeFileUnderConstruction pendingFile =
-          INodeFileUnderConstruction.valueOf( 
-              fsDir.getINode(reassignLeaseOp.path), reassignLeaseOp.path);
+      INodeFile pendingFile = fsDir.getINode(reassignLeaseOp.path).asFile();
+      Preconditions.checkState(pendingFile.isUnderConstruction());
       fsNamesys.reassignLeaseInternal(lease,
           reassignLeaseOp.path, reassignLeaseOp.newHolder, pendingFile);
       break;
@@ -751,9 +749,8 @@ public class FSEditLogLoader {
       if (oldBlock instanceof BlockInfoUnderConstruction &&
           (!isLastBlock || op.shouldCompleteLastBlock())) {
         changeMade = true;
-        fsNamesys.getBlockManager().forceCompleteBlock(
-            (INodeFileUnderConstruction)file,
-            (BlockInfoUnderConstruction)oldBlock);
+        fsNamesys.getBlockManager().forceCompleteBlock(file,
+            (BlockInfoUnderConstruction) oldBlock);
       }
       if (changeMade) {
         // The state or gen-stamp of the block has changed. So, we may be
@@ -774,8 +771,7 @@ public class FSEditLogLoader {
             + path);
       }
       Block oldBlock = oldBlocks[oldBlocks.length - 1];
-      boolean removed = fsDir.unprotectedRemoveBlock(path,
-          (INodeFileUnderConstruction) file, oldBlock);
+      boolean removed = fsDir.unprotectedRemoveBlock(path, file, oldBlock);
       if (!removed && !(op instanceof UpdateBlocksOp)) {
         throw new IOException("Trying to delete non-existant block " + oldBlock);
       }

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

@@ -55,7 +55,6 @@ import org.apache.hadoop.hdfs.server.common.InconsistentFSStateException;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiffList;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectorySnapshottable;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileUnderConstructionWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat;
@@ -659,13 +658,10 @@ public class FSImageFormat {
       // file
       
       // read blocks
-      BlockInfo[] blocks = null;
-      if (numBlocks >= 0) {
-        blocks = new BlockInfo[numBlocks];
-        for (int j = 0; j < numBlocks; j++) {
-          blocks[j] = new BlockInfo(replication);
-          blocks[j].readFields(in);
-        }
+      BlockInfo[] blocks = new BlockInfo[numBlocks];
+      for (int j = 0; j < numBlocks; j++) {
+        blocks[j] = new BlockInfo(replication);
+        blocks[j].readFields(in);
       }
 
       String clientName = "";
@@ -700,10 +696,9 @@ public class FSImageFormat {
       final INodeFile file = new INodeFile(inodeId, localName, permissions,
           modificationTime, atime, blocks, replication, blockSize);
       if (underConstruction) {
-        INodeFileUnderConstruction fileUC = new INodeFileUnderConstruction(
-            file, clientName, clientMachine, null);
-        return fileDiffs == null ? fileUC :
-          new INodeFileUnderConstructionWithSnapshot(fileUC, fileDiffs);
+        file.toUnderConstruction(clientName, clientMachine, null);
+        return fileDiffs == null ? file : new INodeFileWithSnapshot(file,
+            fileDiffs);
       } else {
         return fileDiffs == null ? file : 
           new INodeFileWithSnapshot(file, fileDiffs);
@@ -829,8 +824,8 @@ public class FSImageFormat {
       LOG.info("Number of files under construction = " + size);
 
       for (int i = 0; i < size; i++) {
-        INodeFileUnderConstruction cons = FSImageSerialization
-            .readINodeUnderConstruction(in, namesystem, getLayoutVersion());
+        INodeFile cons = FSImageSerialization.readINodeUnderConstruction(in,
+            namesystem, getLayoutVersion());
         counter.increment();
 
         // verify that file exists in namespace
@@ -848,33 +843,21 @@ public class FSImageFormat {
           final INodesInPath iip = fsDir.getLastINodeInPath(path);
           oldnode = INodeFile.valueOf(iip.getINode(0), path);
         }
-        
-        cons.setLocalName(oldnode.getLocalNameBytes());
-        INodeReference parentRef = oldnode.getParentReference();
-        if (parentRef != null) {
-          cons.setParentReference(parentRef);
-        } else {
-          cons.setParent(oldnode.getParent());
-        }
 
-        if (oldnode instanceof INodeFileWithSnapshot) {
-          cons = new INodeFileUnderConstructionWithSnapshot(cons,
-              ((INodeFileWithSnapshot) oldnode).getDiffs());
+        FileUnderConstructionFeature uc = cons.getFileUnderConstructionFeature();
+        oldnode.toUnderConstruction(uc.getClientName(), uc.getClientMachine(),
+            uc.getClientNode());
+        if (oldnode.numBlocks() > 0) {
+          BlockInfo ucBlock = cons.getLastBlock();
+          // we do not replace the inode, just replace the last block of oldnode
+          BlockInfo info = namesystem.getBlockManager().addBlockCollection(
+              ucBlock, oldnode);
+          oldnode.setBlock(oldnode.numBlocks() - 1, info);
         }
 
         if (!inSnapshot) {
-          fsDir.replaceINodeFile(path, oldnode, cons);
-          namesystem.leaseManager.addLease(cons.getClientName(), path);
-        } else {
-          if (parentRef != null) {
-            // replace oldnode with cons
-            parentRef.setReferredINode(cons);
-          } else {
-            // replace old node in its parent's children list and deleted list
-            oldnode.getParent().replaceChildFileInSnapshot(oldnode, cons);
-            namesystem.dir.addToInodeMap(cons);
-            updateBlocksMap(cons);
-          }
+          namesystem.leaseManager.addLease(cons
+              .getFileUnderConstructionFeature().getClientName(), path);
         }
       }
     }
@@ -955,8 +938,8 @@ public class FSImageFormat {
     private MD5Hash savedDigest;
     private final ReferenceMap referenceMap = new ReferenceMap();
     
-    private final Map<Long, INodeFileUnderConstruction> snapshotUCMap = 
-        new HashMap<Long, INodeFileUnderConstruction>();
+    private final Map<Long, INodeFile> snapshotUCMap =
+        new HashMap<Long, INodeFile>();
 
     /** @throws IllegalStateException if the instance has not yet saved an image */
     private void checkSaved() {
@@ -1096,8 +1079,7 @@ public class FSImageFormat {
           dirNum++;
         } else if (inSnapshot && child.isFile()
             && child.asFile().isUnderConstruction()) {
-          this.snapshotUCMap.put(child.getId(),
-              (INodeFileUnderConstruction) child.asFile());
+          this.snapshotUCMap.put(child.getId(), child.asFile());
         }
         if (i++ % 50 == 0) {
           context.checkCancelled();

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

@@ -108,7 +108,7 @@ public class FSImageSerialization {
   // Helper function that reads in an INodeUnderConstruction
   // from the input stream
   //
-  static INodeFileUnderConstruction readINodeUnderConstruction(
+  static INodeFile readINodeUnderConstruction(
       DataInput in, FSNamesystem fsNamesys, int imgVersion)
       throws IOException {
     byte[] name = readBytes(in);
@@ -141,25 +141,17 @@ public class FSImageSerialization {
     int numLocs = in.readInt();
     assert numLocs == 0 : "Unexpected block locations";
 
-    return new INodeFileUnderConstruction(inodeId,
-                                          name,
-                                          blockReplication, 
-                                          modificationTime,
-                                          preferredBlockSize,
-                                          blocks,
-                                          perm,
-                                          clientName,
-                                          clientMachine,
-                                          null);
+    INodeFile file = new INodeFile(inodeId, name, perm, modificationTime,
+        modificationTime, blocks, blockReplication, preferredBlockSize);
+    file.toUnderConstruction(clientName, clientMachine, null);
+    return file;
   }
 
   // Helper function that writes an INodeUnderConstruction
   // into the input stream
   //
-  static void writeINodeUnderConstruction(DataOutputStream out,
-                                           INodeFileUnderConstruction cons,
-                                           String path) 
-                                           throws IOException {
+  static void writeINodeUnderConstruction(DataOutputStream out, INodeFile cons,
+      String path) throws IOException {
     writeString(path, out);
     out.writeLong(cons.getId());
     out.writeShort(cons.getFileReplication());
@@ -169,8 +161,9 @@ public class FSImageSerialization {
     writeBlocks(cons.getBlocks(), out);
     cons.getPermissionStatus().write(out);
 
-    writeString(cons.getClientName(), out);
-    writeString(cons.getClientMachine(), out);
+    FileUnderConstructionFeature uc = cons.getFileUnderConstructionFeature();
+    writeString(uc.getClientName(), out);
+    writeString(uc.getClientMachine(), out);
 
     out.writeInt(0); //  do not store locations of last block
   }
@@ -194,9 +187,9 @@ public class FSImageSerialization {
     SnapshotFSImageFormat.saveFileDiffList(file, out);
 
     if (writeUnderConstruction) {
-      if (file instanceof INodeFileUnderConstruction) {
+      if (file.isUnderConstruction()) {
         out.writeBoolean(true);
-        final INodeFileUnderConstruction uc = (INodeFileUnderConstruction)file;
+        final FileUnderConstructionFeature uc = file.getFileUnderConstructionFeature();
         writeString(uc.getClientName(), out);
         writeString(uc.getClientMachine(), out);
       } else {

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

@@ -2208,13 +2208,14 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       final DatanodeDescriptor clientNode = 
           blockManager.getDatanodeManager().getDatanodeByHost(clientMachine);
 
-      INodeFileUnderConstruction newNode = dir.addFile(src, permissions,
-          replication, blockSize, holder, clientMachine, clientNode);
+      INodeFile newNode = dir.addFile(src, permissions, replication, blockSize,
+          holder, clientMachine, clientNode);
       if (newNode == null) {
         throw new IOException("DIR* NameSystem.startFile: " +
                               "Unable to add file to namespace.");
       }
-      leaseManager.addLease(newNode.getClientName(), src);
+      leaseManager.addLease(newNode.getFileUnderConstructionFeature()
+          .getClientName(), src);
 
       // record file record in log, record new generation stamp
       getEditLog().logOpenFile(src, newNode, logRetryEntry);
@@ -2306,11 +2307,11 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       boolean writeToEditLog, Snapshot latestSnapshot, boolean logRetryCache)
       throws IOException {
     file = file.recordModification(latestSnapshot, dir.getINodeMap());
-    final INodeFileUnderConstruction cons = file.toUnderConstruction(
-        leaseHolder, clientMachine, clientNode);
+    final INodeFile cons = file.toUnderConstruction(leaseHolder, clientMachine,
+        clientNode);
 
-    dir.replaceINodeFile(src, file, cons);
-    leaseManager.addLease(cons.getClientName(), src);
+    leaseManager.addLease(cons.getFileUnderConstructionFeature()
+        .getClientName(), src);
     
     LocatedBlock ret = blockManager.convertLastBlockToUnderConstruction(cons);
     if (writeToEditLog) {
@@ -2373,7 +2374,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       throws IOException {
     assert hasWriteLock();
     if (fileInode != null && fileInode.isUnderConstruction()) {
-      INodeFileUnderConstruction pendingFile = (INodeFileUnderConstruction) fileInode;
       //
       // If the file is under construction , then it must be in our
       // leases. Find the appropriate lease record.
@@ -2396,7 +2396,9 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       //
       // Find the original holder.
       //
-      lease = leaseManager.getLease(pendingFile.getClientName());
+      FileUnderConstructionFeature uc = fileInode.getFileUnderConstructionFeature();
+      String clientName = uc.getClientName();
+      lease = leaseManager.getLease(clientName);
       if (lease == null) {
         throw new AlreadyBeingCreatedException(
           "failed to create file " + src + " for " + holder +
@@ -2407,26 +2409,26 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
         // close now: no need to wait for soft lease expiration and 
         // close only the file src
         LOG.info("recoverLease: " + lease + ", src=" + src +
-          " from client " + pendingFile.getClientName());
+          " from client " + clientName);
         internalReleaseLease(lease, src, holder);
       } else {
-        assert lease.getHolder().equals(pendingFile.getClientName()) :
+        assert lease.getHolder().equals(clientName) :
           "Current lease holder " + lease.getHolder() +
-          " does not match file creator " + pendingFile.getClientName();
+          " does not match file creator " + clientName;
         //
         // If the original holder has not renewed in the last SOFTLIMIT 
         // period, then start lease recovery.
         //
         if (lease.expiredSoftLimit()) {
           LOG.info("startFile: recover " + lease + ", src=" + src + " client "
-              + pendingFile.getClientName());
+              + clientName);
           boolean isClosed = internalReleaseLease(lease, src, null);
           if(!isClosed)
             throw new RecoveryInProgressException(
                 "Failed to close file " + src +
                 ". Lease recovery is in progress. Try again later.");
         } else {
-          final BlockInfo lastBlock = pendingFile.getLastBlock();
+          final BlockInfo lastBlock = fileInode.getLastBlock();
           if (lastBlock != null
               && lastBlock.getBlockUCState() == BlockUCState.UNDER_RECOVERY) {
             throw new RecoveryInProgressException("Recovery in progress, file ["
@@ -2435,8 +2437,8 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
             throw new AlreadyBeingCreatedException("Failed to create file ["
                 + src + "] for [" + holder + "] on client [" + clientMachine
                 + "], because this file is already being created by ["
-                + pendingFile.getClientName() + "] on ["
-                + pendingFile.getClientMachine() + "]");
+                + clientName + "] on ["
+                + uc.getClientMachine() + "]");
           }
         }
       }
@@ -2566,8 +2568,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       LocatedBlock[] onRetryBlock = new LocatedBlock[1];
       final INode[] inodes = analyzeFileState(
           src, fileId, clientName, previous, onRetryBlock).getINodes();
-      final INodeFileUnderConstruction pendingFile =
-          (INodeFileUnderConstruction) inodes[inodes.length - 1].asFile();
+      final INodeFile pendingFile = inodes[inodes.length - 1].asFile();
 
       if (onRetryBlock[0] != null && onRetryBlock[0].getLocations().length > 0) {
         // This is a retry. Just return the last block if having locations.
@@ -2580,7 +2581,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
             + maxBlocksPerFile);
       }
       blockSize = pendingFile.getPreferredBlockSize();
-      clientNode = pendingFile.getClientNode();
+      clientNode = pendingFile.getFileUnderConstructionFeature().getClientNode();
       replication = pendingFile.getFileReplication();
     } finally {
       readUnlock();
@@ -2604,8 +2605,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       INodesInPath inodesInPath =
           analyzeFileState(src, fileId, clientName, previous, onRetryBlock);
       INode[] inodes = inodesInPath.getINodes();
-      final INodeFileUnderConstruction pendingFile =
-          (INodeFileUnderConstruction) inodes[inodes.length - 1].asFile();
+      final INodeFile pendingFile = inodes[inodes.length - 1].asFile();
 
       if (onRetryBlock[0] != null) {
         if (onRetryBlock[0].getLocations().length > 0) {
@@ -2660,7 +2660,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
 
     Block previousBlock = ExtendedBlock.getLocalBlock(previous);
     final INodesInPath iip = dir.getINodesInPath4Write(src);
-    final INodeFileUnderConstruction pendingFile
+    final INodeFile pendingFile
         = checkLease(src, fileId, clientName, iip.getLastINode());
     BlockInfo lastBlockInFile = pendingFile.getLastBlock();
     if (!Block.matchingIdAndGenStamp(previousBlock, lastBlockInFile)) {
@@ -2766,8 +2766,8 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       src = FSDirectory.resolvePath(src, pathComponents, dir);
 
       //check lease
-      final INodeFileUnderConstruction file = checkLease(src, clientName);
-      clientnode = file.getClientNode();
+      final INodeFile file = checkLease(src, clientName);
+      clientnode = file.getFileUnderConstructionFeature().getClientNode();
       preferredblocksize = file.getPreferredBlockSize();
 
       //find datanode descriptors
@@ -2813,7 +2813,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       //
       // Remove the block from the pending creates list
       //
-      INodeFileUnderConstruction file = checkLease(src, holder);
+      INodeFile file = checkLease(src, holder);
       boolean removed = dir.removeBlock(src, file,
           ExtendedBlock.getLocalBlock(b));
       if (!removed) {
@@ -2835,16 +2835,15 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   }
   
   /** make sure that we still have the lease on this file. */
-  private INodeFileUnderConstruction checkLease(String src, String holder)
+  private INodeFile checkLease(String src, String holder)
       throws LeaseExpiredException, UnresolvedLinkException,
       FileNotFoundException {
     return checkLease(src, INodeId.GRANDFATHER_INODE_ID, holder,
         dir.getINode(src));
   }
   
-  private INodeFileUnderConstruction checkLease(String src, long fileId,
-      String holder, INode inode) throws LeaseExpiredException,
-      FileNotFoundException {
+  private INodeFile checkLease(String src, long fileId, String holder,
+      INode inode) throws LeaseExpiredException, FileNotFoundException {
     assert hasReadLock();
     if (inode == null || !inode.isFile()) {
       Lease lease = leaseManager.getLease(holder);
@@ -2861,13 +2860,13 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
           + (lease != null ? lease.toString()
               : "Holder " + holder + " does not have any open files."));
     }
-    INodeFileUnderConstruction pendingFile = (INodeFileUnderConstruction)file;
-    if (holder != null && !pendingFile.getClientName().equals(holder)) {
+    String clientName = file.getFileUnderConstructionFeature().getClientName();
+    if (holder != null && !clientName.equals(holder)) {
       throw new LeaseExpiredException("Lease mismatch on " + src + " owned by "
-          + pendingFile.getClientName() + " but is accessed by " + holder);
+          + clientName + " but is accessed by " + holder);
     }
-    INodeId.checkId(fileId, pendingFile);
-    return pendingFile;
+    INodeId.checkId(fileId, file);
+    return file;
   }
  
   /**
@@ -2908,7 +2907,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       UnresolvedLinkException, IOException {
     assert hasWriteLock();
     final INodesInPath iip = dir.getLastINodeInPath(src);
-    final INodeFileUnderConstruction pendingFile;
+    final INodeFile pendingFile;
     try {
       pendingFile = checkLease(src, fileId, holder, iip.getINode(0));
     } catch (LeaseExpiredException lee) {
@@ -3599,9 +3598,10 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       checkOperation(OperationCategory.WRITE);
       checkNameNodeSafeMode("Cannot fsync file " + src);
       src = FSDirectory.resolvePath(src, pathComponents, dir);
-      INodeFileUnderConstruction pendingFile  = checkLease(src, clientName);
+      INodeFile pendingFile  = checkLease(src, clientName);
       if (lastBlockLength > 0) {
-        pendingFile.updateLengthOfLastBlock(lastBlockLength);
+        pendingFile.getFileUnderConstructionFeature().updateLengthOfLastBlock(
+            pendingFile, lastBlockLength);
       }
       dir.persistBlocks(src, pendingFile, false);
     } finally {
@@ -3632,8 +3632,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     assert hasWriteLock();
 
     final INodesInPath iip = dir.getLastINodeInPath(src);
-    final INodeFileUnderConstruction pendingFile
-        = INodeFileUnderConstruction.valueOf(iip.getINode(0), src);
+    final INodeFile pendingFile = iip.getINode(0).asFile();
     int nrBlocks = pendingFile.numBlocks();
     BlockInfo[] blocks = pendingFile.getBlocks();
 
@@ -3755,7 +3754,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   }
 
   private Lease reassignLease(Lease lease, String src, String newHolder,
-      INodeFileUnderConstruction pendingFile) {
+      INodeFile pendingFile) {
     assert hasWriteLock();
     if(newHolder == null)
       return lease;
@@ -3765,15 +3764,16 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   }
   
   Lease reassignLeaseInternal(Lease lease, String src, String newHolder,
-      INodeFileUnderConstruction pendingFile) {
+      INodeFile pendingFile) {
     assert hasWriteLock();
-    pendingFile.setClientName(newHolder);
+    pendingFile.getFileUnderConstructionFeature().setClientName(newHolder);
     return leaseManager.reassignLease(lease, src, newHolder);
   }
 
-  private void commitOrCompleteLastBlock(final INodeFileUnderConstruction fileINode,
+  private void commitOrCompleteLastBlock(final INodeFile fileINode,
       final Block commitBlock) throws IOException {
     assert hasWriteLock();
+    Preconditions.checkArgument(fileINode.isUnderConstruction());
     if (!blockManager.commitOrCompleteLastBlock(fileINode, commitBlock)) {
       return;
     }
@@ -3790,19 +3790,21 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     }
   }
 
-  private void finalizeINodeFileUnderConstruction(String src, 
-      INodeFileUnderConstruction pendingFile, Snapshot latestSnapshot) 
-      throws IOException, UnresolvedLinkException {
+  private void finalizeINodeFileUnderConstruction(String src,
+      INodeFile pendingFile, Snapshot latestSnapshot) throws IOException,
+      UnresolvedLinkException {
     assert hasWriteLock();
-    leaseManager.removeLease(pendingFile.getClientName(), src);
+    FileUnderConstructionFeature uc = pendingFile.getFileUnderConstructionFeature();
+    Preconditions.checkArgument(uc != null);
+    leaseManager.removeLease(uc.getClientName(), src);
     
     pendingFile = pendingFile.recordModification(latestSnapshot,
         dir.getINodeMap());
 
     // The file is no longer pending.
-    // Create permanent INode, update blocks
-    final INodeFile newFile = pendingFile.toINodeFile(now());
-    dir.replaceINodeFile(src, pendingFile, newFile);
+    // Create permanent INode, update blocks. No need to replace the inode here
+    // since we just remove the uc feature from pendingFile
+    final INodeFile newFile = pendingFile.toCompleteFile(now());
 
     // close file and persist block allocations for this file
     dir.closeFile(src, newFile);
@@ -3819,12 +3821,12 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   public boolean isInSnapshot(BlockInfoUnderConstruction blockUC) {
     assert hasReadLock();
     final BlockCollection bc = blockUC.getBlockCollection();
-    if (bc == null || !(bc instanceof INodeFileUnderConstruction)) {
+    if (bc == null || !(bc instanceof INodeFile)
+        || !((INodeFile) bc).isUnderConstruction()) {
       return false;
     }
 
-    INodeFileUnderConstruction inodeUC = (INodeFileUnderConstruction) blockUC
-        .getBlockCollection();
+    INodeFile inodeUC = (INodeFile) bc;
     String fullName = inodeUC.getName();
     try {
       if (fullName != null && fullName.startsWith(Path.SEPARATOR)
@@ -3902,11 +3904,9 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
                               + recoveryId + " for block " + lastblock); 
       }
 
-      INodeFileUnderConstruction pendingFile = (INodeFileUnderConstruction)iFile;
-
       if (deleteblock) {
         Block blockToDel = ExtendedBlock.getLocalBlock(lastblock);
-        boolean remove = pendingFile.removeLastBlock(blockToDel);
+        boolean remove = iFile.removeLastBlock(blockToDel);
         if (remove) {
           blockManager.removeBlockFromMap(storedBlock);
         }
@@ -3944,14 +3944,14 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
         // add pipeline locations into the INodeUnderConstruction
         DatanodeDescriptor[] targetArray =
             new DatanodeDescriptor[targetList.size()];
-        pendingFile.setLastBlock(storedBlock, targetList.toArray(targetArray));
+        iFile.setLastBlock(storedBlock, targetList.toArray(targetArray));
       }
 
       if (closeFile) {
-        src = closeFileCommitBlocks(pendingFile, storedBlock);
+        src = closeFileCommitBlocks(iFile, storedBlock);
       } else {
         // If this commit does not want to close the file, persist blocks
-        src = persistBlocks(pendingFile, false);
+        src = persistBlocks(iFile, false);
       }
     } finally {
       writeUnlock();
@@ -3976,10 +3976,8 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
    * @throws IOException
    */
   @VisibleForTesting
-  String closeFileCommitBlocks(INodeFileUnderConstruction pendingFile,
-                                       BlockInfo storedBlock)
+  String closeFileCommitBlocks(INodeFile pendingFile, BlockInfo storedBlock)
       throws IOException {
-
     String src = leaseManager.findPath(pendingFile);
 
     // commit the last block and complete it if it has minimum replicas
@@ -3987,7 +3985,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
 
     //remove lease, close file
     finalizeINodeFileUnderConstruction(src, pendingFile,
-                                       Snapshot.findLatestSnapshot(pendingFile, null));
+        Snapshot.findLatestSnapshot(pendingFile, null));
 
     return src;
   }
@@ -4000,8 +3998,8 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
    * @throws IOException
    */
   @VisibleForTesting
-  String persistBlocks(INodeFileUnderConstruction pendingFile,
-      boolean logRetryCache) throws IOException {
+  String persistBlocks(INodeFile pendingFile, boolean logRetryCache)
+      throws IOException {
     String src = leaseManager.findPath(pendingFile);
     dir.persistBlocks(src, pendingFile, logRetryCache);
     return src;
@@ -5186,13 +5184,12 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     try {
       for (Lease lease : leaseManager.getSortedLeases()) {
         for (String path : lease.getPaths()) {
-          final INodeFileUnderConstruction cons;
+          final INodeFile cons;
           try {
-            cons = INodeFileUnderConstruction.valueOf(dir.getINode(path), path);
+            cons = dir.getINode(path).asFile();
+            Preconditions.checkState(cons.isUnderConstruction());
           } catch (UnresolvedLinkException e) {
             throw new AssertionError("Lease files should reside on this FS");
-          } catch (IOException e) {
-            throw new RuntimeException(e);
           }
           BlockInfo[] blocks = cons.getBlocks();
           if(blocks == null)
@@ -5768,7 +5765,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     return blockId;
   }
 
-  private INodeFileUnderConstruction checkUCBlock(ExtendedBlock block,
+  private INodeFile checkUCBlock(ExtendedBlock block,
       String clientName) throws IOException {
     assert hasWriteLock();
     checkNameNodeSafeMode("Cannot get a new generation stamp and an "
@@ -5784,19 +5781,20 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     
     // check file inode
     final INodeFile file = ((INode)storedBlock.getBlockCollection()).asFile();
-    if (file==null || !file.isUnderConstruction()) {
+    if (file == null || !file.isUnderConstruction()) {
       throw new IOException("The file " + storedBlock + 
           " belonged to does not exist or it is not under construction.");
     }
     
     // check lease
-    INodeFileUnderConstruction pendingFile = (INodeFileUnderConstruction)file;
-    if (clientName == null || !clientName.equals(pendingFile.getClientName())) {
+    if (clientName == null
+        || !clientName.equals(file.getFileUnderConstructionFeature()
+            .getClientName())) {
       throw new LeaseExpiredException("Lease mismatch: " + block + 
           " is accessed by a non lease holder " + clientName); 
     }
 
-    return pendingFile;
+    return file;
   }
   
   /**
@@ -5905,8 +5903,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       throws IOException {
     assert hasWriteLock();
     // check the vadility of the block and lease holder name
-    final INodeFileUnderConstruction pendingFile
-        = checkUCBlock(oldBlock, clientName);
+    final INodeFile pendingFile = checkUCBlock(oldBlock, clientName);
     final BlockInfoUnderConstruction blockinfo
         = (BlockInfoUnderConstruction)pendingFile.getLastBlock();
 
@@ -5950,15 +5947,13 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
    * Serializes leases. 
    */
   void saveFilesUnderConstruction(DataOutputStream out,
-      Map<Long, INodeFileUnderConstruction> snapshotUCMap) throws IOException {
+      Map<Long, INodeFile> snapshotUCMap) throws IOException {
     // This is run by an inferior thread of saveNamespace, which holds a read
     // lock on our behalf. If we took the read lock here, we could block
     // for fairness if a writer is waiting on the lock.
     synchronized (leaseManager) {
-      Map<String, INodeFileUnderConstruction> nodes =
-          leaseManager.getINodesUnderConstruction();
-      for (Map.Entry<String, INodeFileUnderConstruction> entry
-          : nodes.entrySet()) {
+      Map<String, INodeFile> nodes = leaseManager.getINodesUnderConstruction();
+      for (Map.Entry<String, INodeFile> entry : nodes.entrySet()) {
         // TODO: for HDFS-5428, because of rename operations, some
         // under-construction files that are
         // in the current fs directory can also be captured in the
@@ -5967,13 +5962,11 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       }
       
       out.writeInt(nodes.size() + snapshotUCMap.size()); // write the size    
-      for (Map.Entry<String, INodeFileUnderConstruction> entry
-           : nodes.entrySet()) {
+      for (Map.Entry<String, INodeFile> entry : nodes.entrySet()) {
         FSImageSerialization.writeINodeUnderConstruction(
             out, entry.getValue(), entry.getKey());
       }
-      for (Map.Entry<Long, INodeFileUnderConstruction> entry
-          : snapshotUCMap.entrySet()) {
+      for (Map.Entry<Long, INodeFile> entry : snapshotUCMap.entrySet()) {
         // for those snapshot INodeFileUC, we use "/.reserved/.inodes/<inodeid>"
         // as their paths
         StringBuilder b = new StringBuilder();

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

@@ -0,0 +1,99 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode;
+
+import java.io.IOException;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
+import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
+import org.apache.hadoop.hdfs.server.namenode.INode.BlocksMapUpdateInfo;
+
+/**
+ * I-node for file being written.
+ */
+@InterfaceAudience.Private
+public class FileUnderConstructionFeature extends INodeFile.Feature {
+  private String clientName; // lease holder
+  private final String clientMachine;
+  // if client is a cluster node too.
+  private final DatanodeDescriptor clientNode;
+
+  public FileUnderConstructionFeature(final String clientName,
+      final String clientMachine,
+      final DatanodeDescriptor clientNode) {
+    this.clientName = clientName;
+    this.clientMachine = clientMachine;
+    this.clientNode = clientNode;
+  }
+
+  public String getClientName() {
+    return clientName;
+  }
+
+  void setClientName(String clientName) {
+    this.clientName = clientName;
+  }
+
+  public String getClientMachine() {
+    return clientMachine;
+  }
+
+  public DatanodeDescriptor getClientNode() {
+    return clientNode;
+  }
+
+  /**
+   * Update the length for the last block
+   *
+   * @param lastBlockLength
+   *          The length of the last block reported from client
+   * @throws IOException
+   */
+  void updateLengthOfLastBlock(INodeFile f, long lastBlockLength)
+      throws IOException {
+    BlockInfo lastBlock = f.getLastBlock();
+    assert (lastBlock != null) : "The last block for path "
+        + f.getFullPathName() + " is null when updating its length";
+    assert (lastBlock instanceof BlockInfoUnderConstruction)
+        : "The last block for path " + f.getFullPathName()
+            + " is not a BlockInfoUnderConstruction when updating its length";
+    lastBlock.setNumBytes(lastBlockLength);
+  }
+
+  /**
+   * 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.
+   */
+  void cleanZeroSizeBlock(final INodeFile f,
+      final BlocksMapUpdateInfo collectedBlocks) {
+    final BlockInfo[] blocks = f.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);
+        f.removeLastBlock(lastUC);
+      }
+    }
+  }
+}

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

@@ -34,7 +34,6 @@ import org.apache.hadoop.hdfs.protocol.SnapshotAccessControlException;
 import org.apache.hadoop.hdfs.server.namenode.INodeReference.WithCount;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectorySnapshottable;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileUnderConstructionWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 import org.apache.hadoop.hdfs.util.ReadOnlyList;
@@ -205,23 +204,6 @@ public class INodeDirectory extends INodeWithAdditionalFields
     return newDir;
   }
   
-  /**
-   * Used when load fileUC from fsimage. The file to be replaced is actually 
-   * only in snapshot, thus may not be contained in the children list. 
-   * See HDFS-5428 for details.
-   */
-  public void replaceChildFileInSnapshot(INodeFile oldChild,
-      final INodeFile newChild) {
-    if (children != null) {
-      final int i = searchChildren(newChild.getLocalNameBytes());
-      if (i >= 0 && children.get(i).getId() == oldChild.getId()) {
-        // no need to consider reference node here, since we already do the 
-        // replacement in FSImageFormat.Loader#loadFilesUnderConstruction
-        children.set(i, newChild);
-      }
-    }
-  }
-  
   /** Replace the given child with a new child. */
   public void replaceChild(INode oldChild, final INode newChild,
       final INodeMap inodeMap) {
@@ -291,17 +273,6 @@ public class INodeDirectory extends INodeWithAdditionalFields
     return newChild;
   }
 
-  /** Replace a child {@link INodeFile} with an {@link INodeFileUnderConstructionWithSnapshot}. */
-  INodeFileUnderConstructionWithSnapshot replaceChild4INodeFileUcWithSnapshot(
-      final INodeFileUnderConstruction child, final INodeMap inodeMap) {
-    Preconditions.checkArgument(!(child instanceof INodeFileUnderConstructionWithSnapshot),
-        "Child file is already an INodeFileUnderConstructionWithSnapshot, child=" + child);
-    final INodeFileUnderConstructionWithSnapshot newChild
-        = new INodeFileUnderConstructionWithSnapshot(child, null);
-    replaceChildFile(child, newChild, inodeMap);
-    return newChild;
-  }
-
   @Override
   public INodeDirectory recordModification(Snapshot latest,
       final INodeMap inodeMap) throws QuotaExceededException {

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

@@ -20,15 +20,18 @@ package org.apache.hadoop.hdfs.server.namenode;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.PrintWriter;
+import java.util.Arrays;
 import java.util.List;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.fs.permission.PermissionStatus;
+import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockCollection;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
+import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiff;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshot.FileDiffList;
@@ -43,6 +46,22 @@ import com.google.common.base.Preconditions;
 @InterfaceAudience.Private
 public class INodeFile extends INodeWithAdditionalFields
     implements INodeFileAttributes, BlockCollection {
+  /**
+   * A feature contains specific information for a type of INodeFile. E.g.,
+   * we can have separate features for Under-Construction and Snapshot.
+   */
+  public static abstract class Feature {
+    private Feature nextFeature;
+
+    public Feature getNextFeature() {
+      return nextFeature;
+    }
+
+    public void setNextFeature(Feature next) {
+      this.nextFeature = next;
+    }
+  }
+
   /** The same as valueOf(inode, path, false). */
   public static INodeFile valueOf(INode inode, String path
       ) throws FileNotFoundException {
@@ -104,8 +123,11 @@ public class INodeFile extends INodeWithAdditionalFields
 
   private BlockInfo[] blocks;
 
-  INodeFile(long id, byte[] name, PermissionStatus permissions, long mtime, long atime,
-      BlockInfo[] blklist, short replication, long preferredBlockSize) {
+  private Feature headFeature;
+
+  INodeFile(long id, byte[] name, PermissionStatus permissions, long mtime,
+      long atime, BlockInfo[] blklist, short replication,
+      long preferredBlockSize) {
     super(id, name, permissions, mtime, atime);
     header = HeaderFormat.combineReplication(header, replication);
     header = HeaderFormat.combinePreferredBlockSize(header, preferredBlockSize);
@@ -116,6 +138,48 @@ public class INodeFile extends INodeWithAdditionalFields
     super(that);
     this.header = that.header;
     this.blocks = that.blocks;
+    this.headFeature = that.headFeature;
+  }
+
+  /**
+   * If the inode contains a {@link FileUnderConstructionFeature}, return it;
+   * otherwise, return null.
+   */
+  public final FileUnderConstructionFeature getFileUnderConstructionFeature() {
+    for (Feature f = this.headFeature; f != null; f = f.nextFeature) {
+      if (f instanceof FileUnderConstructionFeature) {
+        return (FileUnderConstructionFeature) f;
+      }
+    }
+    return null;
+  }
+
+  /** Is this file under construction? */
+  @Override // BlockCollection
+  public boolean isUnderConstruction() {
+    return getFileUnderConstructionFeature() != null;
+  }
+
+  void addFeature(Feature f) {
+    f.nextFeature = headFeature;
+    headFeature = f;
+  }
+
+  void removeFeature(Feature f) {
+    if (f == headFeature) {
+      headFeature = headFeature.nextFeature;
+      return;
+    } else if (headFeature != null) {
+      Feature prev = headFeature;
+      Feature curr = headFeature.nextFeature;
+      for (; curr != null && curr != f; prev = curr, curr = curr.nextFeature)
+        ;
+      if (curr != null) {
+        prev.nextFeature = curr.nextFeature;
+        return;
+      }
+    }
+    throw new IllegalStateException("Feature " + f + " not found.");
   }
 
   /** @return true unconditionally. */
@@ -130,22 +194,88 @@ public class INodeFile extends INodeWithAdditionalFields
     return this;
   }
 
-  /** Is this file under construction? */
-  public boolean isUnderConstruction() {
-    return false;
-  }
+  /* Start of Under-Construction Feature */
 
   /** Convert this file to an {@link INodeFileUnderConstruction}. */
-  public INodeFileUnderConstruction toUnderConstruction(
-      String clientName,
-      String clientMachine,
+  public INodeFile toUnderConstruction(String clientName, String clientMachine,
       DatanodeDescriptor clientNode) {
     Preconditions.checkState(!isUnderConstruction(),
         "file is already an INodeFileUnderConstruction");
-    return new INodeFileUnderConstruction(this,
-        clientName, clientMachine, clientNode); 
+    FileUnderConstructionFeature uc = new FileUnderConstructionFeature(
+        clientName, clientMachine, clientNode);
+    addFeature(uc);
+    return this;
   }
 
+  /**
+   * Convert the file to a complete file, i.e., to remove the Under-Construction
+   * feature.
+   */
+  public INodeFile toCompleteFile(long mtime) {
+    FileUnderConstructionFeature uc = getFileUnderConstructionFeature();
+    if (uc != null) {
+      assertAllBlocksComplete();
+      removeFeature(uc);
+      this.setModificationTime(mtime);
+    }
+    return this;
+  }
+
+  /** Assert all blocks are complete. */
+  private void assertAllBlocksComplete() {
+    if (blocks == null) {
+      return;
+    }
+    for (int i = 0; i < blocks.length; i++) {
+      Preconditions.checkState(blocks[i].isComplete(), "Failed to finalize"
+          + " %s %s since blocks[%s] is non-complete, where blocks=%s.",
+          getClass().getSimpleName(), this, i, Arrays.asList(blocks));
+    }
+  }
+
+  @Override //BlockCollection
+  public void setBlock(int index, BlockInfo blk) {
+    this.blocks[index] = blk;
+  }
+
+  @Override // BlockCollection
+  public BlockInfoUnderConstruction setLastBlock(BlockInfo lastBlock,
+      DatanodeDescriptor[] locations) throws IOException {
+    Preconditions.checkState(isUnderConstruction());
+
+    if (numBlocks() == 0) {
+      throw new IOException("Failed to set last block: File is empty.");
+    }
+    BlockInfoUnderConstruction ucBlock =
+      lastBlock.convertToBlockUnderConstruction(
+          BlockUCState.UNDER_CONSTRUCTION, locations);
+    ucBlock.setBlockCollection(this);
+    setBlock(numBlocks() - 1, ucBlock);
+    return ucBlock;
+  }
+
+  /**
+   * Remove a block from the block list. This block should be
+   * the last one on the list.
+   */
+  boolean removeLastBlock(Block oldblock) {
+    if (blocks == null || blocks.length == 0) {
+      return false;
+    }
+    int size_1 = blocks.length - 1;
+    if (!blocks[size_1].equals(oldblock)) {
+      return false;
+    }
+
+    //copy to a new list
+    BlockInfo[] newlist = new BlockInfo[size_1];
+    System.arraycopy(blocks, 0, newlist, 0, size_1);
+    setBlocks(newlist);
+    return true;
+  }
+
+  /* End of Under-Construction Feature */
+
   @Override
   public INodeFileAttributes getSnapshotINode(final Snapshot snapshot) {
     return this;
@@ -266,11 +396,6 @@ public class INodeFile extends INodeWithAdditionalFields
     }
   }
 
-  /** Set the block of the file at the given index. */
-  public void setBlock(int idx, BlockInfo blk) {
-    this.blocks[idx] = blk;
-  }
-
   /** Set the blocks. */
   public void setBlocks(BlockInfo[] blocks) {
     this.blocks = blocks;
@@ -286,6 +411,11 @@ public class INodeFile extends INodeWithAdditionalFields
       // this only happens when deleting the current file
       computeQuotaUsage(counts, false);
       destroyAndCollectBlocks(collectedBlocks, removedINodes);
+    } else if (snapshot == null && prior != null) {
+      FileUnderConstructionFeature uc = getFileUnderConstructionFeature();
+      if (uc != null) {
+        uc.cleanZeroSizeBlock(this, collectedBlocks);
+      }
     }
     return counts;
   }

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

@@ -1,247 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-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;
-import org.apache.hadoop.hdfs.protocol.Block;
-import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
-import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
-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;
-
-import com.google.common.base.Preconditions;
-
-/**
- * I-node for file being written.
- */
-@InterfaceAudience.Private
-public class INodeFileUnderConstruction extends INodeFile implements MutableBlockCollection {
-  /** Cast INode to INodeFileUnderConstruction. */
-  public static INodeFileUnderConstruction valueOf(INode inode, String path
-      ) throws FileNotFoundException {
-    final INodeFile file = INodeFile.valueOf(inode, path);
-    if (!file.isUnderConstruction()) {
-      throw new FileNotFoundException("File is not under construction: " + path);
-    }
-    return (INodeFileUnderConstruction)file;
-  }
-
-  private  String clientName;         // lease holder
-  private final String clientMachine;
-  private final DatanodeDescriptor clientNode; // if client is a cluster node too.
-  
-  INodeFileUnderConstruction(long id,
-                             PermissionStatus permissions,
-                             short replication,
-                             long preferredBlockSize,
-                             long modTime,
-                             String clientName,
-                             String clientMachine,
-                             DatanodeDescriptor clientNode) {
-    this(id, null, replication, modTime, preferredBlockSize, BlockInfo.EMPTY_ARRAY,
-        permissions, clientName, clientMachine, clientNode);
-  }
-
-  INodeFileUnderConstruction(long id,
-                             byte[] name,
-                             short blockReplication,
-                             long modificationTime,
-                             long preferredBlockSize,
-                             BlockInfo[] blocks,
-                             PermissionStatus perm,
-                             String clientName,
-                             String clientMachine,
-                             DatanodeDescriptor clientNode) {
-    super(id, name, perm, modificationTime, modificationTime,
-        blocks, blockReplication, preferredBlockSize);
-    this.clientName = clientName;
-    this.clientMachine = clientMachine;
-    this.clientNode = clientNode;
-  }
-  
-  public INodeFileUnderConstruction(final INodeFile that,
-      final String clientName,
-      final String clientMachine,
-      final DatanodeDescriptor clientNode) {
-    super(that);
-    this.clientName = clientName;
-    this.clientMachine = clientMachine;
-    this.clientNode = clientNode;
-  }
-
-  public String getClientName() {
-    return clientName;
-  }
-
-  void setClientName(String clientName) {
-    this.clientName = clientName;
-  }
-
-  public String getClientMachine() {
-    return clientMachine;
-  }
-
-  public DatanodeDescriptor getClientNode() {
-    return clientNode;
-  }
-
-  /** @return true unconditionally. */
-  @Override
-  public final boolean isUnderConstruction() {
-    return true;
-  }
-
-  /**
-   * Converts an INodeFileUnderConstruction to an INodeFile.
-   * The original modification time is used as the access time.
-   * The new modification is the specified mtime.
-   */
-  protected INodeFile toINodeFile(long mtime) {
-    assertAllBlocksComplete();
-
-    final INodeFile f = new INodeFile(getId(), getLocalNameBytes(),
-        getPermissionStatus(), mtime, getModificationTime(),
-        getBlocks(), getFileReplication(), getPreferredBlockSize());
-    f.setParent(getParent());
-    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 {
-    if (isInLatestSnapshot(latest)) {
-      INodeFileUnderConstructionWithSnapshot newFile = getParent()
-          .replaceChild4INodeFileUcWithSnapshot(this, inodeMap)
-          .recordModification(latest, inodeMap);
-      return newFile;
-    } else {
-      return this;
-    }
-  }
-
-  /** Assert all blocks are complete. */
-  protected void assertAllBlocksComplete() {
-    final BlockInfo[] blocks = getBlocks();
-    for (int i = 0; i < blocks.length; i++) {
-      Preconditions.checkState(blocks[i].isComplete(), "Failed to finalize"
-          + " %s %s since blocks[%s] is non-complete, where blocks=%s.",
-          getClass().getSimpleName(), this, i, Arrays.asList(getBlocks()));
-    }
-  }
-
-  /**
-   * Remove a block from the block list. This block should be
-   * the last one on the list.
-   */
-  boolean removeLastBlock(Block oldblock) {
-    final BlockInfo[] blocks = getBlocks();
-    if (blocks == null || blocks.length == 0) {
-      return false;
-    }
-    int size_1 = blocks.length - 1;
-    if (!blocks[size_1].equals(oldblock)) {
-      return false;
-    }
-
-    //copy to a new list
-    BlockInfo[] newlist = new BlockInfo[size_1];
-    System.arraycopy(blocks, 0, newlist, 0, size_1);
-    setBlocks(newlist);
-    return true;
-  }
-
-  /**
-   * Convert the last block of the file to an under-construction block.
-   * Set its locations.
-   */
-  @Override
-  public BlockInfoUnderConstruction setLastBlock(BlockInfo lastBlock,
-      DatanodeDescriptor[] targets) throws IOException {
-    if (numBlocks() == 0) {
-      throw new IOException("Failed to set last block: File is empty.");
-    }
-    BlockInfoUnderConstruction ucBlock =
-      lastBlock.convertToBlockUnderConstruction(
-          BlockUCState.UNDER_CONSTRUCTION, targets);
-    ucBlock.setBlockCollection(this);
-    setBlock(numBlocks()-1, ucBlock);
-    return ucBlock;
-  }
-
-  /**
-   * Update the length for the last block
-   * 
-   * @param lastBlockLength
-   *          The length of the last block reported from client
-   * @throws IOException
-   */
-  void updateLengthOfLastBlock(long lastBlockLength) throws IOException {
-    BlockInfo lastBlock = this.getLastBlock();
-    assert (lastBlock != null) : "The last block for path "
-        + this.getFullPathName() + " is null when updating its length";
-    assert (lastBlock instanceof BlockInfoUnderConstruction) : "The last block for path "
-        + this.getFullPathName()
-        + " is not a BlockInfoUnderConstruction when updating its length";
-    lastBlock.setNumBytes(lastBlockLength);
-  }
-  
-}

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

@@ -182,9 +182,11 @@ public class LeaseManager {
   /**
    * Finds the pathname for the specified pendingFile
    */
-  public synchronized String findPath(INodeFileUnderConstruction pendingFile)
+  public synchronized String findPath(INodeFile pendingFile)
       throws IOException {
-    Lease lease = getLease(pendingFile.getClientName());
+    FileUnderConstructionFeature uc = pendingFile.getFileUnderConstructionFeature();
+    Preconditions.checkArgument(uc != null);
+    Lease lease = getLease(uc.getClientName());
     if (lease != null) {
       String src = lease.findPath(pendingFile);
       if (src != null) {
@@ -253,7 +255,7 @@ public class LeaseManager {
     /**
      * @return the path associated with the pendingFile and null if not found.
      */
-    private String findPath(INodeFileUnderConstruction pendingFile) {
+    private String findPath(INodeFile pendingFile) {
       try {
         for (String src : paths) {
           INode node = fsnamesystem.dir.getINode(src);
@@ -433,14 +435,14 @@ public class LeaseManager {
    * @return list of inodes
    * @throws UnresolvedLinkException
    */
-  Map<String, INodeFileUnderConstruction> getINodesUnderConstruction() {
-    Map<String, INodeFileUnderConstruction> inodes =
-        new TreeMap<String, INodeFileUnderConstruction>();
+  Map<String, INodeFile> getINodesUnderConstruction() {
+    Map<String, INodeFile> inodes = new TreeMap<String, INodeFile>();
     for (String p : sortedLeasesByPath.keySet()) {
       // verify that path exists in namespace
       try {
-        INode node = fsnamesystem.dir.getINode(p);
-        inodes.put(p, INodeFileUnderConstruction.valueOf(node, p));
+        INodeFile node = INodeFile.valueOf(fsnamesystem.dir.getINode(p), p);
+        Preconditions.checkState(node.isUnderConstruction());
+        inodes.put(p, node);
       } catch (IOException ioe) {
         LOG.error(ioe);
       }

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

@@ -38,7 +38,6 @@ import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectoryAttributes;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectoryWithQuota;
-import org.apache.hadoop.hdfs.server.namenode.INodeFile;
 import org.apache.hadoop.hdfs.server.namenode.INodeMap;
 import org.apache.hadoop.hdfs.server.namenode.INodeReference;
 import org.apache.hadoop.hdfs.server.namenode.Quota;
@@ -593,14 +592,6 @@ public class INodeDirectoryWithSnapshot extends INodeDirectoryWithQuota {
     return removed;
   }
   
-  @Override
-  public void replaceChildFileInSnapshot(final INodeFile oldChild,
-      final INodeFile newChild) {
-    super.replaceChildFileInSnapshot(oldChild, newChild);
-    diffs.replaceChild(ListType.DELETED, oldChild, newChild);
-    diffs.replaceChild(ListType.CREATED, oldChild, newChild);
-  }
-  
   @Override
   public void replaceChild(final INode oldChild, final INode newChild,
       final INodeMap inodeMap) {

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

@@ -1,130 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.hadoop.hdfs.server.namenode.snapshot;
-
-import java.util.List;
-
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
-import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
-import org.apache.hadoop.hdfs.server.namenode.INode;
-import org.apache.hadoop.hdfs.server.namenode.INodeFile;
-import org.apache.hadoop.hdfs.server.namenode.INodeFileAttributes;
-import org.apache.hadoop.hdfs.server.namenode.INodeFileUnderConstruction;
-import org.apache.hadoop.hdfs.server.namenode.INodeMap;
-import org.apache.hadoop.hdfs.server.namenode.Quota;
-
-/**
- * Represent an {@link INodeFileUnderConstruction} that is snapshotted.
- */
-@InterfaceAudience.Private
-public class INodeFileUnderConstructionWithSnapshot
-    extends INodeFileUnderConstruction implements FileWithSnapshot {
-  private final FileDiffList diffs;
-  private boolean isCurrentFileDeleted = false;
-
-  INodeFileUnderConstructionWithSnapshot(final INodeFile f,
-      final String clientName,
-      final String clientMachine,
-      final DatanodeDescriptor clientNode,
-      final FileDiffList diffs) {
-    super(f, clientName, clientMachine, clientNode);
-    this.diffs = diffs != null? diffs: new FileDiffList();
-  }
-
-  /**
-   * Construct an {@link INodeFileUnderConstructionWithSnapshot} based on an
-   * {@link INodeFileUnderConstruction}.
-   * 
-   * @param f The given {@link INodeFileUnderConstruction} instance
-   */
-  public INodeFileUnderConstructionWithSnapshot(INodeFileUnderConstruction f,
-      final FileDiffList diffs) {
-    this(f, f.getClientName(), f.getClientMachine(), f.getClientNode(), diffs);
-  }
-  
-  @Override
-  protected INodeFileWithSnapshot toINodeFile(final long mtime) {
-    assertAllBlocksComplete();
-    final long atime = getModificationTime();
-    final INodeFileWithSnapshot f = new INodeFileWithSnapshot(this, getDiffs());
-    f.setModificationTime(mtime);
-    f.setAccessTime(atime);
-    return f;
-  }
-
-  @Override
-  public boolean isCurrentFileDeleted() {
-    return isCurrentFileDeleted;
-  }
-  
-  @Override
-  public void deleteCurrentFile() {
-    isCurrentFileDeleted = true;
-  }
-
-  @Override
-  public INodeFileAttributes getSnapshotINode(Snapshot snapshot) {
-    return diffs.getSnapshotINode(snapshot, this);
-  }
-
-  @Override
-  public INodeFileUnderConstructionWithSnapshot recordModification(
-      final Snapshot latest, final INodeMap inodeMap)
-      throws QuotaExceededException {
-    if (isInLatestSnapshot(latest) && !shouldRecordInSrcSnapshot(latest)) {
-      diffs.saveSelf2Snapshot(latest, this, null);
-    }
-    return this;
-  }
-
-  @Override
-  public INodeFile asINodeFile() {
-    return this;
-  }
-
-  @Override
-  public FileDiffList getDiffs() {
-    return diffs;
-  }
-
-  @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) { // delete the current file
-      if (!isCurrentFileDeleted()) {
-        recordModification(prior, null);
-        deleteCurrentFile();
-      }
-      Util.collectBlocksAndClear(this, collectedBlocks, removedINodes);
-      return Quota.Counts.newInstance();
-    } else { // delete a snapshot
-      prior = getDiffs().updatePrior(snapshot, prior);
-      return diffs.deleteSnapshotDiff(snapshot, prior, this, collectedBlocks,
-          removedINodes, countDiffChange);
-    }
-  }
-
-  @Override
-  public String toDetailString() {
-    return super.toDetailString()
-        + (isCurrentFileDeleted()? " (DELETED), ": ", ") + diffs;
-  }
-}

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

@@ -21,7 +21,6 @@ import java.util.List;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
-import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INodeFile;
 import org.apache.hadoop.hdfs.server.namenode.INodeFileAttributes;
@@ -47,15 +46,6 @@ public class INodeFileWithSnapshot extends INodeFile
     this.diffs = diffs != null? diffs: new FileDiffList();
   }
 
-  @Override
-  public INodeFileUnderConstructionWithSnapshot toUnderConstruction(
-      final String clientName,
-      final String clientMachine,
-      final DatanodeDescriptor clientNode) {
-    return new INodeFileUnderConstructionWithSnapshot(this,
-        clientName, clientMachine, clientNode, getDiffs());
-  }
-
   @Override
   public boolean isCurrentFileDeleted() {
     return isCurrentFileDeleted;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicy.java

@@ -1113,10 +1113,11 @@ public class TestReplicationPolicy {
     assertTheChosenBlocks(chosenBlocks, 1, 0, 0, 0, 0);
 
     final BlockInfo info = new BlockInfo(block1, 1);
-    final MutableBlockCollection mbc = mock(MutableBlockCollection.class);
+    final BlockCollection mbc = mock(BlockCollection.class);
     when(mbc.getLastBlock()).thenReturn(info);
     when(mbc.getPreferredBlockSize()).thenReturn(block1.getNumBytes() + 1);
     when(mbc.getBlockReplication()).thenReturn((short)1);
+    when(mbc.isUnderConstruction()).thenReturn(true);
     ContentSummary cs = mock(ContentSummary.class);
     when(cs.getLength()).thenReturn((long)1);
     when(mbc.computeContentSummary()).thenReturn(cs);

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

@@ -82,9 +82,10 @@ public class CreateEditsLog {
          blocks[iB].setBlockId(currentBlockId++);
       }
 
-      INodeFileUnderConstruction inode = new INodeFileUnderConstruction(
-          inodeId.nextValue(), null, replication, 0, blockSize, blocks, p, "",
-          "", null);
+      final INodeFile inode = new INodeFile(inodeId.nextValue(), null,
+          p, 0L, 0L, blocks, replication, blockSize);
+      inode.toUnderConstruction("", "", null);
+
      // Append path to filename with information about blockIDs 
       String path = "_" + iF + "_B" + blocks[0].getBlockId() + 
                     "_to_B" + blocks[blocksPerFile-1].getBlockId() + "_";
@@ -96,9 +97,10 @@ public class CreateEditsLog {
         dirInode = new INodeDirectory(inodeId.nextValue(), null, p, 0L);
         editLog.logMkDir(currentDir, dirInode);
       }
-      editLog.logOpenFile(filePath,
-          new INodeFileUnderConstruction(inodeId.nextValue(), p, replication,
-              0, blockSize, "", "", null), false);
+      INodeFile fileUc = new INodeFile(inodeId.nextValue(), null,
+          p, 0L, 0L, BlockInfo.EMPTY_ARRAY, replication, blockSize);
+      fileUc.toUnderConstruction("", "", null);
+      editLog.logOpenFile(filePath, fileUc, false);
       editLog.logCloseFile(filePath, inode);
 
       if (currentBlockId - bidAtSync >= 2000) { // sync every 2K blocks

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

@@ -43,8 +43,7 @@ public class TestCommitBlockSynchronization {
   private static final long length = 200;
   private static final long genStamp = 300;
 
-  private FSNamesystem makeNameSystemSpy(Block block,
-                                         INodeFileUnderConstruction file)
+  private FSNamesystem makeNameSystemSpy(Block block, INodeFile file)
       throws IOException {
     Configuration conf = new Configuration();
     FSImage image = new FSImage(conf);
@@ -58,21 +57,26 @@ public class TestCommitBlockSynchronization {
     blockInfo.setGenerationStamp(genStamp);
     blockInfo.initializeBlockRecovery(genStamp);
     doReturn(true).when(file).removeLastBlock(any(Block.class));
+    doReturn(true).when(file).isUnderConstruction();
 
     doReturn(blockInfo).when(namesystemSpy).getStoredBlock(any(Block.class));
     doReturn("").when(namesystemSpy).closeFileCommitBlocks(
-        any(INodeFileUnderConstruction.class),
-        any(BlockInfo.class));
+        any(INodeFile.class), any(BlockInfo.class));
     doReturn("").when(namesystemSpy).persistBlocks(
-        any(INodeFileUnderConstruction.class), anyBoolean());
+        any(INodeFile.class), anyBoolean());
     doReturn(mock(FSEditLog.class)).when(namesystemSpy).getEditLog();
 
     return namesystemSpy;
   }
 
+  private INodeFile mockFileUnderConstruction() {
+    INodeFile file = mock(INodeFile.class);
+    return file;
+  }
+
   @Test
   public void testCommitBlockSynchronization() throws IOException {
-    INodeFileUnderConstruction file = mock(INodeFileUnderConstruction.class);
+    INodeFile file = mockFileUnderConstruction();
     Block block = new Block(blockId, length, genStamp);
     FSNamesystem namesystemSpy = makeNameSystemSpy(block, file);
     DatanodeID[] newTargets = new DatanodeID[0];
@@ -100,7 +104,7 @@ public class TestCommitBlockSynchronization {
 
   @Test
   public void testCommitBlockSynchronization2() throws IOException {
-    INodeFileUnderConstruction file = mock(INodeFileUnderConstruction.class);
+    INodeFile file = mockFileUnderConstruction();
     Block block = new Block(blockId, length, genStamp);
     FSNamesystem namesystemSpy = makeNameSystemSpy(block, file);
     DatanodeID[] newTargets = new DatanodeID[0];
@@ -124,7 +128,7 @@ public class TestCommitBlockSynchronization {
 
   @Test
   public void testCommitBlockSynchronizationWithDelete() throws IOException {
-    INodeFileUnderConstruction file = mock(INodeFileUnderConstruction.class);
+    INodeFile file = mockFileUnderConstruction();
     Block block = new Block(blockId, length, genStamp);
     FSNamesystem namesystemSpy = makeNameSystemSpy(block, file);
     DatanodeID[] newTargets = new DatanodeID[0];
@@ -144,7 +148,7 @@ public class TestCommitBlockSynchronization {
 
   @Test
   public void testCommitBlockSynchronizationWithClose() throws IOException {
-    INodeFileUnderConstruction file = mock(INodeFileUnderConstruction.class);
+    INodeFile file = mockFileUnderConstruction();
     Block block = new Block(blockId, length, genStamp);
     FSNamesystem namesystemSpy = makeNameSystemSpy(block, file);
     DatanodeID[] newTargets = new DatanodeID[0];
@@ -171,7 +175,7 @@ public class TestCommitBlockSynchronization {
   @Test
   public void testCommitBlockSynchronizationWithCloseAndNonExistantTarget()
       throws IOException {
-    INodeFileUnderConstruction file = mock(INodeFileUnderConstruction.class);
+    INodeFile file = mockFileUnderConstruction();
     Block block = new Block(blockId, length, genStamp);
     FSNamesystem namesystemSpy = makeNameSystemSpy(block, file);
     DatanodeID[] newTargets = new DatanodeID[]{

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

@@ -63,6 +63,7 @@ import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
 import org.apache.hadoop.hdfs.server.namenode.NNStorage.NameNodeDirType;
 import org.apache.hadoop.hdfs.server.namenode.metrics.NameNodeMetrics;
@@ -152,9 +153,10 @@ public class TestEditLog {
       FSEditLog editLog = namesystem.getEditLog();
 
       for (int i = 0; i < numTransactions; i++) {
-        INodeFileUnderConstruction inode = new INodeFileUnderConstruction(
-            namesystem.allocateNewInodeId(), p, replication, blockSize, 0, "",
-            "", null);
+        INodeFile inode = new INodeFile(namesystem.allocateNewInodeId(), null,
+            p, 0L, 0L, BlockInfo.EMPTY_ARRAY, replication, blockSize);
+        inode.toUnderConstruction("", "", null);
+
         editLog.logOpenFile("/filename" + (startIndex + i), inode, false);
         editLog.logCloseFile("/filename" + (startIndex + i), inode);
         editLog.logSync();

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

@@ -29,6 +29,8 @@ import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
+import junit.framework.Assert;
+
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
@@ -59,6 +61,7 @@ import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
+import org.apache.hadoop.util.Time;
 import org.junit.Test;
 import org.mockito.Mockito;
 
@@ -282,14 +285,6 @@ public class TestINodeFile {
         assertTrue(fnfe.getMessage().contains("File does not exist"));
       }
 
-      //cast to INodeFileUnderConstruction, should fail
-      try {
-        INodeFileUnderConstruction.valueOf(from, path);
-        fail();
-      } catch(FileNotFoundException fnfe) {
-        assertTrue(fnfe.getMessage().contains("File does not exist"));
-      }
-
       //cast to INodeDirectory, should fail
       try {
         INodeDirectory.valueOf(from, path);
@@ -306,14 +301,6 @@ public class TestINodeFile {
       final INodeFile f = INodeFile.valueOf(from, path);
       assertTrue(f == from);
 
-      //cast to INodeFileUnderConstruction, should fail
-      try {
-        INodeFileUnderConstruction.valueOf(from, path);
-        fail();
-      } catch(IOException ioe) {
-        assertTrue(ioe.getMessage().contains("File is not under construction"));
-      }
-
       //cast to INodeDirectory, should fail
       try {
         INodeDirectory.valueOf(from, path);
@@ -324,19 +311,14 @@ public class TestINodeFile {
     }
 
     {//cast from INodeFileUnderConstruction
-      final INode from = new INodeFileUnderConstruction(
-          INodeId.GRANDFATHER_INODE_ID, perm, replication, 0L, 0L, "client",
-          "machine", null);
+      final INode from = new INodeFile(
+          INodeId.GRANDFATHER_INODE_ID, null, perm, 0L, 0L, null, replication, 1024L);
+      from.asFile().toUnderConstruction("client", "machine", null);
     
       //cast to INodeFile, should success
       final INodeFile f = INodeFile.valueOf(from, path);
       assertTrue(f == from);
 
-      //cast to INodeFileUnderConstruction, should success
-      final INodeFileUnderConstruction u = INodeFileUnderConstruction.valueOf(
-          from, path);
-      assertTrue(u == from);
-
       //cast to INodeDirectory, should fail
       try {
         INodeDirectory.valueOf(from, path);
@@ -358,14 +340,6 @@ public class TestINodeFile {
         assertTrue(fnfe.getMessage().contains("Path is not a file"));
       }
 
-      //cast to INodeFileUnderConstruction, should fail
-      try {
-        INodeFileUnderConstruction.valueOf(from, path);
-        fail();
-      } catch(FileNotFoundException fnfe) {
-        assertTrue(fnfe.getMessage().contains("Path is not a file"));
-      }
-
       //cast to INodeDirectory, should success
       final INodeDirectory d = INodeDirectory.valueOf(from, path);
       assertTrue(d == from);
@@ -1015,4 +989,24 @@ public class TestINodeFile {
       }
     }
   }
+
+  @Test
+  public void testFileUnderConstruction() {
+    replication = 3;
+    final INodeFile file = new INodeFile(INodeId.GRANDFATHER_INODE_ID, null,
+        perm, 0L, 0L, null, replication, 1024L);
+    assertFalse(file.isUnderConstruction());
+
+    final String clientName = "client";
+    final String clientMachine = "machine";
+    file.toUnderConstruction(clientName, clientMachine, null);
+    assertTrue(file.isUnderConstruction());
+    FileUnderConstructionFeature uc = file.getFileUnderConstructionFeature();
+    assertEquals(clientName, uc.getClientName());
+    assertEquals(clientMachine, uc.getClientMachine());
+    Assert.assertNull(uc.getClientNode());
+
+    file.toCompleteFile(Time.now());
+    assertFalse(file.isUnderConstruction());
+  }
 }

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

@@ -66,7 +66,6 @@ import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
 import org.apache.hadoop.hdfs.server.namenode.INodeFile;
-import org.apache.hadoop.hdfs.server.namenode.INodeFileUnderConstruction;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotTestHelper;
 import org.apache.hadoop.io.EnumSetWritable;
 import org.apache.hadoop.io.IOUtils;
@@ -719,8 +718,8 @@ public class TestRetryCacheWithHA {
 
     @Override
     boolean checkNamenodeBeforeReturn() throws Exception {
-      INodeFileUnderConstruction fileNode = (INodeFileUnderConstruction) cluster
-          .getNamesystem(0).getFSDirectory().getINode4Write(file).asFile();
+      INodeFile fileNode = cluster.getNamesystem(0).getFSDirectory()
+          .getINode4Write(file).asFile();
       BlockInfoUnderConstruction blkUC = 
           (BlockInfoUnderConstruction) (fileNode.getBlocks())[1];
       int datanodeNum = blkUC.getExpectedLocations().length;

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

@@ -1227,8 +1227,9 @@ public class TestRenameWithSnapshots {
       out.write(content);
       fooRef = fsdir.getINode4Write(foo2.toString());
       assertTrue(fooRef instanceof INodeReference.DstReference);
-      INode fooNode = fooRef.asFile();
-      assertTrue(fooNode instanceof INodeFileUnderConstructionWithSnapshot);
+      INodeFile fooNode = fooRef.asFile();
+      assertTrue(fooNode instanceof INodeFileWithSnapshot);
+      assertTrue(fooNode.isUnderConstruction());
     } finally {
       if (out != null) {
         out.close();
@@ -1237,8 +1238,9 @@ public class TestRenameWithSnapshots {
     
     fooRef = fsdir.getINode4Write(foo2.toString());
     assertTrue(fooRef instanceof INodeReference.DstReference);
-    INode fooNode = fooRef.asFile();
+    INodeFile fooNode = fooRef.asFile();
     assertTrue(fooNode instanceof INodeFileWithSnapshot);
+    assertFalse(fooNode.isUnderConstruction());
     
     restartClusterAndCheckImage(true);
   }

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

@@ -314,7 +314,9 @@ public class TestSnapshotBlocksMap {
     assertEquals(BLOCKSIZE, blks[0].getNumBytes());
   }
 
-  /** Make sure we delete 0-sized block when deleting an INodeFileUC */
+  /**
+   * Make sure we delete 0-sized block when deleting an under-construction file
+   */
   @Test
   public void testDeletionWithZeroSizeBlock2() throws Exception {
     final Path foo = new Path("/foo");