HDFS-5554. Flatten INodeFile hierarchy: Replace INodeFileWithSnapshot with FileWithSnapshotFeature. Contributed by jing9

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1548796 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -236,6 +236,9 @@ Trunk (Unreleased)
     HDFS-5312. Generate HTTP / HTTPS URL in DFSUtil#getInfoServer() based on the 
     configured http policy. (Haohui Mai via jing9)
 
+    HDFS-5554. Flatten INodeFile hierarchy: Replace INodeFileWithSnapshot with
+    FileWithSnapshotFeature.  (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/namenode/FSImageFormat.java

@@ -55,7 +55,6 @@
 import org.apache.hadoop.hdfs.server.namenode.snapshot.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.INodeFileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat.ReferenceMap;
@@ -697,11 +696,9 @@ INode loadINode(final byte[] localName, boolean isSnapshotINode,
           modificationTime, atime, blocks, replication, blockSize);
       if (underConstruction) {
         file.toUnderConstruction(clientName, clientMachine, null);
-        return fileDiffs == null ? file : new INodeFileWithSnapshot(file,
+          return fileDiffs == null ? file : new INodeFile(file, fileDiffs);
-            fileDiffs);
       } else {
-        return fileDiffs == null ? file : 
+          return fileDiffs == null ? file : new INodeFile(file, fileDiffs);
-          new INodeFileWithSnapshot(file, fileDiffs);
       }
     } else if (numBlocks == -1) {
       //directory

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

@@ -202,7 +202,6 @@
 import org.apache.hadoop.hdfs.server.namenode.metrics.NameNodeMetrics;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectorySnapshottable;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectorySnapshottable.SnapshotDiffInfo;
-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.SnapshotManager;
 import org.apache.hadoop.hdfs.server.namenode.startupprogress.Phase;
@@ -1765,7 +1764,7 @@ private void concatInternal(FSPermissionChecker pc, String target,
       throw new HadoopIllegalArgumentException("concat: target file "
           + target + " is empty");
     }
-    if (trgInode instanceof INodeFileWithSnapshot) {
+    if (trgInode.isWithSnapshot()) {
       throw new HadoopIllegalArgumentException("concat: target file "
           + target + " is in a snapshot");
     }

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.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.INodeFileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 import org.apache.hadoop.hdfs.util.ReadOnlyList;
 
@@ -322,23 +321,6 @@ INodeReference.WithName replaceChild4ReferenceWithName(INode oldChild,
     replaceChild(oldChild, ref, null);
     return ref;
   }
-  
-  private void replaceChildFile(final INodeFile oldChild,
-      final INodeFile newChild, final INodeMap inodeMap) {
-    replaceChild(oldChild, newChild, inodeMap);
-    oldChild.clear();
-    newChild.updateBlockCollection();
-  }
-
-  /** Replace a child {@link INodeFile} with an {@link INodeFileWithSnapshot}. */
-  INodeFileWithSnapshot replaceChild4INodeFileWithSnapshot(
-      final INodeFile child, final INodeMap inodeMap) {
-    Preconditions.checkArgument(!(child instanceof INodeFileWithSnapshot),
-        "Child file is already an INodeFileWithSnapshot, child=" + child);
-    final INodeFileWithSnapshot newChild = new INodeFileWithSnapshot(child);
-    replaceChildFile(child, newChild, inodeMap);
-    return newChild;
-  }
 
   @Override
   public INodeDirectory recordModification(Snapshot latest,

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

@@ -34,7 +34,7 @@
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileDiff;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.FileDiffList;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileWithSnapshot;
+import org.apache.hadoop.hdfs.server.namenode.snapshot.FileWithSnapshotFeature;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -140,24 +140,11 @@ public INodeFile(INodeFile that) {
     this.blocks = that.blocks;
     this.headFeature = that.headFeature;
   }
-
+  
-  /**
+  public INodeFile(INodeFile that, FileDiffList diffs) {
-   * If the inode contains a {@link FileUnderConstructionFeature}, return it;
+    this(that);
-   * otherwise, return null.
+    Preconditions.checkArgument(!that.isWithSnapshot());
-   */
+    this.addSnapshotFeature(diffs);
-  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;
   }
 
   private void addFeature(Feature f) {
@@ -182,6 +169,25 @@ public final INodeFile asFile() {
 
   /* Start of Under-Construction Feature */
 
+  /**
+   * 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;
+  }
+
   /** Convert this file to an {@link INodeFileUnderConstruction}. */
   INodeFile toUnderConstruction(String clientName, String clientMachine,
       DatanodeDescriptor clientNode) {
@@ -266,24 +272,75 @@ boolean removeLastBlock(Block oldblock) {
   }
 
   /* End of Under-Construction Feature */
+  
+  /* Start of Snapshot Feature */
+
+  private FileWithSnapshotFeature addSnapshotFeature(FileDiffList diffs) {
+    FileWithSnapshotFeature sf = new FileWithSnapshotFeature(diffs);
+    this.addFeature(sf);
+    return sf;
+  }
+  
+  /**
+   * If feature list contains a {@link FileWithSnapshotFeature}, return it;
+   * otherwise, return null.
+   */
+  public final FileWithSnapshotFeature getFileWithSnapshotFeature() {
+    for (Feature f = headFeature; f != null; f = f.nextFeature) {
+      if (f instanceof FileWithSnapshotFeature) {
+        return (FileWithSnapshotFeature) f;
+      }
+    }
+    return null;
+  }
+
+  /** Is this file has the snapshot feature? */
+  public final boolean isWithSnapshot() {
+    return getFileWithSnapshotFeature() != null;
+  }
+    
+  @Override
+  public String toDetailString() {
+    FileWithSnapshotFeature sf = this.getFileWithSnapshotFeature();
+    return super.toDetailString() + (sf == null ? "" : sf.getDetailedString()); 
+  }
 
   @Override
   public INodeFileAttributes getSnapshotINode(final Snapshot snapshot) {
-    return this;
+    FileWithSnapshotFeature sf = this.getFileWithSnapshotFeature();
+    if (sf != null) {
+      return sf.getSnapshotINode(this, snapshot);
+    } else {
+      return this;
+    }
   }
 
   @Override
   public INodeFile recordModification(final Snapshot latest,
       final INodeMap inodeMap) throws QuotaExceededException {
     if (isInLatestSnapshot(latest)) {
-      INodeFileWithSnapshot newFile = getParent()
+      // the file is in snapshot, create a snapshot feature if it does not have
-          .replaceChild4INodeFileWithSnapshot(this, inodeMap)
+      FileWithSnapshotFeature sf = this.getFileWithSnapshotFeature();
-          .recordModification(latest, inodeMap);
+      if (sf == null) {
-      return newFile;
+        sf = addSnapshotFeature(null);
-    } else {
+      }
-      return this;
+      // record self in the diff list if necessary
+      if (!shouldRecordInSrcSnapshot(latest)) {
+        sf.getDiffs().saveSelf2Snapshot(latest, this, null);
+      }
     }
+    return this;
   }
+  
+  public FileDiffList getDiffs() {
+    FileWithSnapshotFeature sf = this.getFileWithSnapshotFeature();
+    if (sf != null) {
+      return sf.getDiffs();
+    }
+    return null;
+  }
+  
+  /* End of Snapshot Feature */
 
   /** @return the replication factor of the file. */
   public final short getFileReplication(Snapshot snapshot) {
@@ -295,14 +352,23 @@ public final short getFileReplication(Snapshot snapshot) {
   }
 
   /** The same as getFileReplication(null). */
-  @Override
+  @Override // INodeFileAttributes
   public final short getFileReplication() {
     return getFileReplication(null);
   }
 
-  @Override
+  @Override // BlockCollection
   public short getBlockReplication() {
-    return getFileReplication(null);
+    short max = getFileReplication(null);
+    FileWithSnapshotFeature sf = this.getFileWithSnapshotFeature();
+    if (sf != null) {
+      short maxInSnapshot = sf.getMaxBlockRepInDiffs();
+      if (sf.isCurrentFileDeleted()) {
+        return maxInSnapshot;
+      }
+      max = maxInSnapshot > max ? maxInSnapshot : max;
+    }
+    return max;
   }
 
   /** Set the replication factor of this file. */
@@ -395,12 +461,20 @@ public Quota.Counts cleanSubtree(final Snapshot snapshot, Snapshot prior,
       final BlocksMapUpdateInfo collectedBlocks,
       final List<INode> removedINodes, final boolean countDiffChange)
       throws QuotaExceededException {
+    FileWithSnapshotFeature sf = getFileWithSnapshotFeature();
+    if (sf != null) {
+      return sf.cleanFile(this, snapshot, prior, collectedBlocks,
+          removedINodes, countDiffChange);
+    }
     Quota.Counts counts = Quota.Counts.newInstance();
-    if (snapshot == null && prior == null) {   
+    if (snapshot == null && prior == null) {
-      // this only happens when deleting the current file
+      // this only happens when deleting the current file and the file is not
+      // in any snapshot
       computeQuotaUsage(counts, false);
       destroyAndCollectBlocks(collectedBlocks, removedINodes);
     } else if (snapshot == null && prior != null) {
+      // when deleting the current file and the file is in snapshot, we should
+      // clean the 0-sized block if the file is UC
       FileUnderConstructionFeature uc = getFileUnderConstructionFeature();
       if (uc != null) {
         uc.cleanZeroSizeBlock(this, collectedBlocks);
@@ -422,8 +496,9 @@ public void destroyAndCollectBlocks(BlocksMapUpdateInfo collectedBlocks,
     clear();
     removedINodes.add(this);
     
-    if (this instanceof INodeFileWithSnapshot) {
+    FileWithSnapshotFeature sf = getFileWithSnapshotFeature();
-      ((INodeFileWithSnapshot) this).getDiffs().clear();
+    if (sf != null) {
+      sf.clearDiffs();
     }
   }
   
@@ -438,8 +513,9 @@ public final Quota.Counts computeQuotaUsage(Quota.Counts counts,
       boolean useCache, int lastSnapshotId) {
     long nsDelta = 1;
     final long dsDelta;
-    if (this instanceof INodeFileWithSnapshot) {
+    FileWithSnapshotFeature sf = getFileWithSnapshotFeature();
-      FileDiffList fileDiffList = ((INodeFileWithSnapshot) this).getDiffs();
+    if (sf != null) {
+      FileDiffList fileDiffList = sf.getDiffs();
       Snapshot last = fileDiffList.getLastSnapshot();
       List<FileDiff> diffs = fileDiffList.asList();
 
@@ -471,16 +547,16 @@ public final ContentSummaryComputationContext  computeContentSummary(
   private void computeContentSummary4Snapshot(final Content.Counts counts) {
     // file length and diskspace only counted for the latest state of the file
     // i.e. either the current state or the last snapshot
-    if (this instanceof INodeFileWithSnapshot) {
+    FileWithSnapshotFeature sf = getFileWithSnapshotFeature();
-      final INodeFileWithSnapshot withSnapshot = (INodeFileWithSnapshot) this;
+    if (sf != null) {
-      final FileDiffList diffs = withSnapshot.getDiffs();
+      final FileDiffList diffs = sf.getDiffs();
       final int n = diffs.asList().size();
       counts.add(Content.FILE, n);
-      if (n > 0 && withSnapshot.isCurrentFileDeleted()) {
+      if (n > 0 && sf.isCurrentFileDeleted()) {
         counts.add(Content.LENGTH, diffs.getLast().getFileSize());
       }
 
-      if (withSnapshot.isCurrentFileDeleted()) {
+      if (sf.isCurrentFileDeleted()) {
         final long lastFileSize = diffs.getLast().getFileSize();
         counts.add(Content.DISKSPACE, lastFileSize * getBlockReplication());
       }
@@ -488,8 +564,8 @@ private void computeContentSummary4Snapshot(final Content.Counts counts) {
   }
 
   private void computeContentSummary4Current(final Content.Counts counts) {
-    if (this instanceof INodeFileWithSnapshot
+    FileWithSnapshotFeature sf = this.getFileWithSnapshotFeature();
-        && ((INodeFileWithSnapshot) this).isCurrentFileDeleted()) {
+    if (sf != null && sf.isCurrentFileDeleted()) {
       return;
     }
 
@@ -508,8 +584,9 @@ public final long computeFileSize() {
    * otherwise, get the file size from the given snapshot.
    */
   public final long computeFileSize(Snapshot snapshot) {
-    if (snapshot != null && this instanceof INodeFileWithSnapshot) {
+    FileWithSnapshotFeature sf = this.getFileWithSnapshotFeature();
-      final FileDiff d = ((INodeFileWithSnapshot) this).getDiffs().getDiff(
+    if (snapshot != null && sf != null) {
+      final FileDiff d = sf.getDiffs().getDiff(
           snapshot);
       if (d != null) {
         return d.getFileSize();

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

@@ -27,7 +27,6 @@
 import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectoryWithSnapshot;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeFileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 
 import com.google.common.base.Preconditions;
@@ -102,9 +101,8 @@ static Snapshot getPriorSnapshot(INodeReference ref) {
     }
     if (wn != null) {
       INode referred = wc.getReferredINode();
-      if (referred instanceof INodeFileWithSnapshot) {
+      if (referred.isFile() && referred.asFile().isWithSnapshot()) {
-        return ((INodeFileWithSnapshot) referred).getDiffs().getPrior(
+        return referred.asFile().getDiffs().getPrior(wn.lastSnapshotId);
-            wn.lastSnapshotId);
       } else if (referred instanceof INodeDirectoryWithSnapshot) { 
         return ((INodeDirectoryWithSnapshot) referred).getDiffs().getPrior(
             wn.lastSnapshotId);
@@ -547,9 +545,8 @@ public void destroyAndCollectBlocks(BlocksMapUpdateInfo collectedBlocks,
     private Snapshot getSelfSnapshot() {
       INode referred = getReferredINode().asReference().getReferredINode();
       Snapshot snapshot = null;
-      if (referred instanceof INodeFileWithSnapshot) {
+      if (referred.isFile() && referred.asFile().isWithSnapshot()) {
-        snapshot = ((INodeFileWithSnapshot) referred).getDiffs().getPrior(
+        snapshot = referred.asFile().getDiffs().getPrior(lastSnapshotId);
-            lastSnapshotId);
       } else if (referred instanceof INodeDirectoryWithSnapshot) {
         snapshot = ((INodeDirectoryWithSnapshot) referred).getDiffs().getPrior(
             lastSnapshotId);
@@ -637,12 +634,12 @@ public void destroyAndCollectBlocks(
         Snapshot snapshot = getSelfSnapshot(prior);
         
         INode referred = getReferredINode().asReference().getReferredINode();
-        if (referred instanceof INodeFileWithSnapshot) {
+        if (referred.isFile() && referred.asFile().isWithSnapshot()) {
-          // if referred is a file, it must be a FileWithSnapshot since we did
+          // if referred is a file, it must be a file with Snapshot since we did
           // recordModification before the rename
-          INodeFileWithSnapshot sfile = (INodeFileWithSnapshot) referred;
+          INodeFile file = referred.asFile();
           // make sure we mark the file as deleted
-          sfile.deleteCurrentFile();
+          file.getFileWithSnapshotFeature().deleteCurrentFile();
           try {
             // when calling cleanSubtree of the referred node, since we 
             // compute quota usage updates before calling this destroy 
@@ -671,9 +668,8 @@ private Snapshot getSelfSnapshot(final Snapshot prior) {
       WithCount wc = (WithCount) getReferredINode().asReference();
       INode referred = wc.getReferredINode();
       Snapshot lastSnapshot = null;
-      if (referred instanceof INodeFileWithSnapshot) {
+      if (referred.isFile() && referred.asFile().isWithSnapshot()) {
-        lastSnapshot = ((INodeFileWithSnapshot) referred).getDiffs()
+        lastSnapshot = referred.asFile().getDiffs().getLastSnapshot();
-            .getLastSnapshot(); 
       } else if (referred instanceof INodeDirectoryWithSnapshot) {
         lastSnapshot = ((INodeDirectoryWithSnapshot) referred)
             .getLastSnapshot();

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

@@ -33,7 +33,7 @@
  * The difference of an {@link INodeFile} between two snapshots.
  */
 public class FileDiff extends
-    AbstractINodeDiff<INodeFileWithSnapshot, INodeFileAttributes, FileDiff> {
+    AbstractINodeDiff<INodeFile, INodeFileAttributes, FileDiff> {
 
   /** The file size at snapshot creation time. */
   private final long fileSize;
@@ -56,11 +56,12 @@ public long getFileSize() {
   }
   
   @Override
-  Quota.Counts combinePosteriorAndCollectBlocks(
+  Quota.Counts combinePosteriorAndCollectBlocks(INodeFile currentINode,
-      INodeFileWithSnapshot currentINode, FileDiff posterior,
+      FileDiff posterior, BlocksMapUpdateInfo collectedBlocks,
-      BlocksMapUpdateInfo collectedBlocks, final List<INode> removedINodes) {
+      final List<INode> removedINodes) {
-    return currentINode.updateQuotaAndCollectBlocks(posterior, collectedBlocks,
+    return currentINode.getFileWithSnapshotFeature()
-        removedINodes);
+        .updateQuotaAndCollectBlocks(currentINode, posterior, collectedBlocks,
+            removedINodes);
   }
   
   @Override
@@ -84,9 +85,10 @@ void write(DataOutput out, ReferenceMap referenceMap) throws IOException {
   }
 
   @Override
-  Quota.Counts destroyDiffAndCollectBlocks(INodeFileWithSnapshot currentINode,
+  Quota.Counts destroyDiffAndCollectBlocks(INodeFile currentINode,
       BlocksMapUpdateInfo collectedBlocks, final List<INode> removedINodes) {
-    return currentINode.updateQuotaAndCollectBlocks(this, collectedBlocks,
+    return currentINode.getFileWithSnapshotFeature()
-        removedINodes);
+        .updateQuotaAndCollectBlocks(currentINode, this, collectedBlocks,
+            removedINodes);
   }
 }

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

@@ -17,19 +17,20 @@
  */
 package org.apache.hadoop.hdfs.server.namenode.snapshot;
 
+import org.apache.hadoop.hdfs.server.namenode.INodeFile;
 import org.apache.hadoop.hdfs.server.namenode.INodeFileAttributes;
 
 /** A list of FileDiffs for storing snapshot data. */
 public class FileDiffList extends
-    AbstractINodeDiffList<INodeFileWithSnapshot, INodeFileAttributes, FileDiff> {
+    AbstractINodeDiffList<INodeFile, INodeFileAttributes, FileDiff> {
   
   @Override
-  FileDiff createDiff(Snapshot snapshot, INodeFileWithSnapshot file) {
+  FileDiff createDiff(Snapshot snapshot, INodeFile file) {
     return new FileDiff(snapshot, file);
   }
   
   @Override
-  INodeFileAttributes createSnapshotCopy(INodeFileWithSnapshot currentINode) {
+  INodeFileAttributes createSnapshotCopy(INodeFile currentINode) {
     return new INodeFileAttributes.SnapshotCopy(currentINode);
   }
 }

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

@@ -23,90 +23,51 @@
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.namenode.INode;
+import org.apache.hadoop.hdfs.server.namenode.INode.BlocksMapUpdateInfo;
 import org.apache.hadoop.hdfs.server.namenode.INodeFile;
 import org.apache.hadoop.hdfs.server.namenode.INodeFileAttributes;
-import org.apache.hadoop.hdfs.server.namenode.INodeMap;
 import org.apache.hadoop.hdfs.server.namenode.Quota;
 
 /**
- * Represent an {@link INodeFile} that is snapshotted.
+ * Feature for file with snapshot-related information.
  */
 @InterfaceAudience.Private
-public class INodeFileWithSnapshot extends INodeFile {
+public class FileWithSnapshotFeature extends INodeFile.Feature {
   private final FileDiffList diffs;
   private boolean isCurrentFileDeleted = false;
-
+  
-  public INodeFileWithSnapshot(INodeFile f) {
+  public FileWithSnapshotFeature(FileDiffList diffs) {
-    this(f, f instanceof INodeFileWithSnapshot ? 
-        ((INodeFileWithSnapshot) f).getDiffs() : null);
-  }
-
-  public INodeFileWithSnapshot(INodeFile f, FileDiffList diffs) {
-    super(f);
     this.diffs = diffs != null? diffs: new FileDiffList();
   }
 
-  /** Is the current file deleted? */
   public boolean isCurrentFileDeleted() {
     return isCurrentFileDeleted;
   }
   
-  /** Delete the file from the current tree */
+  /** 
+   * We need to distinguish two scenarios:
+   * 1) the file is still in the current file directory, it has been modified 
+   *    before while it is included in some snapshot
+   * 2) the file is not in the current file directory (deleted), but it is in
+   *    some snapshot, thus we still keep this inode
+   * For both scenarios the file has snapshot feature. We set 
+   * {@link #isCurrentFileDeleted} to true for 2).
+   */
   public void deleteCurrentFile() {
     isCurrentFileDeleted = true;
   }
 
-  @Override
+  public INodeFileAttributes getSnapshotINode(INodeFile f, Snapshot snapshot) {
-  public INodeFileAttributes getSnapshotINode(Snapshot snapshot) {
+    return diffs.getSnapshotINode(snapshot, f);
-    return diffs.getSnapshotINode(snapshot, this);
   }
 
-  @Override
-  public INodeFileWithSnapshot recordModification(final Snapshot latest,
-      final INodeMap inodeMap) throws QuotaExceededException {
-    if (isInLatestSnapshot(latest) && !shouldRecordInSrcSnapshot(latest)) {
-      diffs.saveSelf2Snapshot(latest, this, null);
-    }
-    return this;
-  }
-
-  /** @return the file diff list. */
   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();
-      }
-      this.collectBlocksAndClear(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;
-  }
   
-  /** 
+  /** @return the max replication factor in diffs */
-   * @return block replication, which is the max file replication among
+  public short getMaxBlockRepInDiffs() {
-   *         the file and the diff list.
+    short max = 0;
-   */
-  @Override
-  public short getBlockReplication() {
-    short max = isCurrentFileDeleted() ? 0 : getFileReplication();
     for(FileDiff d : getDiffs()) {
       if (d.snapshotINode != null) {
         final short replication = d.snapshotINode.getFileReplication();
@@ -118,33 +79,79 @@ public short getBlockReplication() {
     return max;
   }
   
+  public String getDetailedString() {
+    return (isCurrentFileDeleted()? "(DELETED), ": ", ") + diffs;
+  }
+  
+  public Quota.Counts cleanFile(final INodeFile file, final Snapshot snapshot,
+      Snapshot prior, final BlocksMapUpdateInfo collectedBlocks,
+      final List<INode> removedINodes, final boolean countDiffChange)
+      throws QuotaExceededException {
+    if (snapshot == null) {
+      // delete the current file while the file has snapshot feature
+      if (!isCurrentFileDeleted()) {
+        file.recordModification(prior, null);
+        deleteCurrentFile();
+      }
+      collectBlocksAndClear(file, collectedBlocks, removedINodes);
+      return Quota.Counts.newInstance();
+    } else { // delete the snapshot
+      prior = getDiffs().updatePrior(snapshot, prior);
+      return diffs.deleteSnapshotDiff(snapshot, prior, file, collectedBlocks,
+          removedINodes, countDiffChange);
+    }
+  }
+  
+  public void clearDiffs() {
+    this.diffs.clear();
+  }
+  
+  public Quota.Counts updateQuotaAndCollectBlocks(INodeFile file,
+      FileDiff removed, BlocksMapUpdateInfo collectedBlocks,
+      final List<INode> removedINodes) {
+    long oldDiskspace = file.diskspaceConsumed();
+    if (removed.snapshotINode != null) {
+      short replication = removed.snapshotINode.getFileReplication();
+      short currentRepl = file.getBlockReplication();
+      if (currentRepl == 0) {
+        oldDiskspace = file.computeFileSize(true, true) * replication;
+      } else if (replication > currentRepl) {  
+        oldDiskspace = oldDiskspace / file.getBlockReplication() * replication;
+      }
+    }
+    
+    collectBlocksAndClear(file, collectedBlocks, removedINodes);
+    
+    long dsDelta = oldDiskspace - file.diskspaceConsumed();
+    return Quota.Counts.newInstance(0, dsDelta);
+  }
+  
   /**
    * If some blocks at the end of the block list no longer belongs to
    * any inode, collect them and update the block list.
    */
-  void collectBlocksAndClear(final BlocksMapUpdateInfo info,
+  private void collectBlocksAndClear(final INodeFile file,
-      final List<INode> removedINodes) {
+      final BlocksMapUpdateInfo info, final List<INode> removedINodes) {
     // check if everything is deleted.
     if (isCurrentFileDeleted() && getDiffs().asList().isEmpty()) {
-      destroyAndCollectBlocks(info, removedINodes);
+      file.destroyAndCollectBlocks(info, removedINodes);
       return;
     }
-
     // find max file size.
     final long max;
     if (isCurrentFileDeleted()) {
       final FileDiff last = getDiffs().getLast();
       max = last == null? 0: last.getFileSize();
     } else { 
-      max = computeFileSize();
+      max = file.computeFileSize();
     }
 
-    collectBlocksBeyondMax(max, info);
+    collectBlocksBeyondMax(file, max, info);
   }
 
-  private void collectBlocksBeyondMax(final long max,
+  private void collectBlocksBeyondMax(final INodeFile file, final long max,
       final BlocksMapUpdateInfo collectedBlocks) {
-    final BlockInfo[] oldBlocks = getBlocks();
+    final BlockInfo[] oldBlocks = file.getBlocks();
     if (oldBlocks != null) {
       //find the minimum n such that the size of the first n blocks > max
       int n = 0;
@@ -164,7 +171,7 @@ private void collectBlocksBeyondMax(final long max,
         }
         
         // set new blocks
-        setBlocks(newBlocks);
+        file.setBlocks(newBlocks);
 
         // collect the blocks beyond max.  
         if (collectedBlocks != null) {
@@ -175,24 +182,4 @@ private void collectBlocksBeyondMax(final long max,
       }
     }
   }
-  
-  Quota.Counts updateQuotaAndCollectBlocks(FileDiff removed,
-      BlocksMapUpdateInfo collectedBlocks, final List<INode> removedINodes) {
-    long oldDiskspace = this.diskspaceConsumed();
-    if (removed.snapshotINode != null) {
-      short replication = removed.snapshotINode.getFileReplication();
-      short currentRepl = getBlockReplication();
-      if (currentRepl == 0) {
-        oldDiskspace = computeFileSize(true, true) * replication;
-      } else if (replication > currentRepl) {  
-        oldDiskspace = oldDiskspace / getBlockReplication()
-            * replication;
-      }
-    }
-    
-    this.collectBlocksAndClear(collectedBlocks, removedINodes);
-    
-    long dsDelta = oldDiskspace - diskspaceConsumed();
-    return Quota.Counts.newInstance(0, dsDelta);
-  }
 }

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

@@ -34,9 +34,9 @@
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
-import org.apache.hadoop.hdfs.protocol.SnapshotException;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffType;
+import org.apache.hadoop.hdfs.protocol.SnapshotException;
 import org.apache.hadoop.hdfs.server.namenode.Content;
 import org.apache.hadoop.hdfs.server.namenode.ContentSummaryComputationContext;
 import org.apache.hadoop.hdfs.server.namenode.INode;
@@ -432,8 +432,8 @@ private void computeDiffRecursively(INode node, List<byte[]> parentPath,
           parentPath.remove(parentPath.size() - 1);
         }
       }
-    } else if (node.isFile() && node.asFile() instanceof INodeFileWithSnapshot) {
+    } else if (node.isFile() && node.asFile().isWithSnapshot()) {
-      INodeFileWithSnapshot file = (INodeFileWithSnapshot) node.asFile();
+      INodeFile file = node.asFile();
       Snapshot earlierSnapshot = diffReport.isFromEarlier() ? diffReport.from
           : diffReport.to;
       Snapshot laterSnapshot = diffReport.isFromEarlier() ? diffReport.to

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

@@ -37,6 +37,7 @@
 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.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;
@@ -803,10 +804,9 @@ private static Quota.Counts cleanDeletedINode(INode inode,
         }
         // For DstReference node, since the node is not in the created list of
         // prior, we should treat it as regular file/dir
-      } else if (topNode.isFile()
+      } else if (topNode.isFile() && topNode.asFile().isWithSnapshot()) {
-          && topNode.asFile() instanceof INodeFileWithSnapshot) {
+        INodeFile file = topNode.asFile();
-        INodeFileWithSnapshot fs = (INodeFileWithSnapshot) topNode.asFile();
+        counts.add(file.getDiffs().deleteSnapshotDiff(post, prior, file,
-        counts.add(fs.getDiffs().deleteSnapshotDiff(post, prior, fs,
             collectedBlocks, removedINodes, countDiffChange));
       } else if (topNode.isDirectory()) {
         INodeDirectory dir = topNode.asDirectory();

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

@@ -97,8 +97,7 @@ public static void saveDirectoryDiffList(final INodeDirectory dir,
   
   public static void saveFileDiffList(final INodeFile file,
       final DataOutput out) throws IOException {
-    saveINodeDiffs(file instanceof INodeFileWithSnapshot?
+    saveINodeDiffs(file.getDiffs(), out, null);
-        ((INodeFileWithSnapshot) file).getDiffs(): null, out, null);
   }
 
   public static FileDiffList loadFileDiffList(DataInput in,

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

@@ -32,7 +32,6 @@
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 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.INodeFileWithSnapshot;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 import org.junit.AfterClass;
 import org.junit.Assert;
@@ -239,7 +238,7 @@ public void testSnapshotPathINodes() throws Exception {
     // The last INode should be the INode for sub1
     final INode last = nodesInPath.getLastINode();
     assertEquals(last.getFullPathName(), sub1.toString());
-    assertFalse(last instanceof INodeFileWithSnapshot);
+    assertFalse(last instanceof INodeFile);
     
     String[] invalidPathComponent = {"invalidDir", "foo", ".snapshot", "bar"};
     Path invalidPath = new Path(invalidPathComponent[0]);
@@ -287,7 +286,7 @@ public void testSnapshotPathINodesAfterDeletion() throws Exception {
       // Check the INode for file1 (snapshot file)
       final INode inode = inodes[inodes.length - 1];
       assertEquals(file1.getName(), inode.getLocalName());
-      assertEquals(INodeFileWithSnapshot.class, inode.getClass());
+      assertTrue(inode.asFile().isWithSnapshot());
     }
 
     // Check the INodes for path /TestSnapshot/sub1/file1
@@ -391,6 +390,8 @@ public void testSnapshotPathINodesAfterModification() throws Exception {
     // The last INode should be associated with file1
     assertEquals(inodes[components.length - 1].getFullPathName(),
         file1.toString());
+    // record the modification time of the inode
+    final long modTime = inodes[inodes.length - 1].getModificationTime();
     
     // Create a snapshot for the dir, and check the inodes for the path
     // pointing to a snapshot file
@@ -414,10 +415,10 @@ public void testSnapshotPathINodesAfterModification() throws Exception {
     // Check the INode for snapshot of file1
     INode snapshotFileNode = ssInodes[ssInodes.length - 1]; 
     assertEquals(snapshotFileNode.getLocalName(), file1.getName());
-    assertTrue(snapshotFileNode instanceof INodeFileWithSnapshot);
+    assertTrue(snapshotFileNode.asFile().isWithSnapshot());
     // The modification time of the snapshot INode should be the same with the
     // original INode before modification
-    assertEquals(inodes[inodes.length - 1].getModificationTime(),
+    assertEquals(modTime,
         snapshotFileNode.getModificationTime(ssNodesInPath.getPathSnapshot()));
 
     // Check the INode for /TestSnapshot/sub1/file1 again
@@ -432,7 +433,6 @@ public void testSnapshotPathINodesAfterModification() throws Exception {
     final int last = components.length - 1;
     assertEquals(newInodes[last].getFullPathName(), file1.toString());
     // The modification time of the INode for file3 should have been changed
-    Assert.assertFalse(inodes[last].getModificationTime()
+    Assert.assertFalse(modTime == newInodes[last].getModificationTime());
-        == newInodes[last].getModificationTime());
   }
 }

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

@@ -176,7 +176,7 @@ public void testSnapshotWhileAppending() throws Exception {
     dirNode = (INodeDirectorySnapshottable) fsdir.getINode(dir.toString());
     last = dirNode.getDiffs().getLast();
     Snapshot s1 = last.snapshot;
-    assertTrue(fileNode instanceof INodeFileWithSnapshot);
+    assertTrue(fileNode.isWithSnapshot());
     assertEquals(BLOCKSIZE * 3, fileNode.computeFileSize(s1));
     
     // 4. modify file --> append without closing stream --> take snapshot -->

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

@@ -403,8 +403,7 @@ public void testRenameFileAcrossSnapshottableDirs() throws Exception {
     final Path foo_s3 = SnapshotTestHelper.getSnapshotPath(sdir1, "s3",
         "foo");
     assertFalse(hdfs.exists(foo_s3));
-    INodeFileWithSnapshot sfoo = (INodeFileWithSnapshot) fsdir.getINode(
+    INodeFile sfoo = fsdir.getINode(newfoo.toString()).asFile();
-        newfoo.toString()).asFile();
     assertEquals("s2", sfoo.getDiffs().getLastSnapshot().getRoot()
         .getLocalName());
   }
@@ -604,8 +603,7 @@ public void testRenameFileAndDeleteSnapshot() throws Exception {
     status = hdfs.getFileStatus(foo_s2);
     assertEquals(REPL, status.getReplication());
     
-    INodeFileWithSnapshot snode = (INodeFileWithSnapshot) fsdir.getINode(
+    INodeFile snode = fsdir.getINode(newfoo.toString()).asFile();
-        newfoo.toString()).asFile();
     assertEquals(1, snode.getDiffs().asList().size());
     assertEquals("s2", snode.getDiffs().getLastSnapshot().getRoot()
         .getLocalName());
@@ -763,8 +761,7 @@ public void testRenameMoreThanOnceAcrossSnapDirs() throws Exception {
         .asDirectory();
     assertEquals(1, foo.getDiffs().asList().size());
     assertEquals("s1", foo.getLastSnapshot().getRoot().getLocalName());
-    INodeFileWithSnapshot bar1 = (INodeFileWithSnapshot) fsdir.getINode4Write(
+    INodeFile bar1 = fsdir.getINode4Write(bar1_dir1.toString()).asFile();
-        bar1_dir1.toString()).asFile();
     assertEquals(1, bar1.getDiffs().asList().size());
     assertEquals("s1", bar1.getDiffs().getLastSnapshot().getRoot()
         .getLocalName());
@@ -774,7 +771,7 @@ public void testRenameMoreThanOnceAcrossSnapDirs() throws Exception {
     INodeReference.WithCount barWithCount = (WithCount) barRef
         .getReferredINode();
     assertEquals(2, barWithCount.getReferenceCount());
-    INodeFileWithSnapshot bar = (INodeFileWithSnapshot) barWithCount.asFile();
+    INodeFile bar = barWithCount.asFile();
     assertEquals(1, bar.getDiffs().asList().size());
     assertEquals("s1", bar.getDiffs().getLastSnapshot().getRoot()
         .getLocalName());
@@ -984,8 +981,7 @@ public void testRenameMoreThanOnceAcrossSnapDirs_2() throws Exception {
     assertEquals("s333", fooDiffs.get(2).snapshot.getRoot().getLocalName());
     assertEquals("s22", fooDiffs.get(1).snapshot.getRoot().getLocalName());
     assertEquals("s1", fooDiffs.get(0).snapshot.getRoot().getLocalName());
-    INodeFileWithSnapshot bar1 = (INodeFileWithSnapshot) fsdir.getINode4Write(
+    INodeFile bar1 = fsdir.getINode4Write(bar1_dir1.toString()).asFile();
-        bar1_dir1.toString()).asFile();
     List<FileDiff> bar1Diffs = bar1.getDiffs().asList();
     assertEquals(3, bar1Diffs.size());
     assertEquals("s333", bar1Diffs.get(2).snapshot.getRoot().getLocalName());
@@ -997,7 +993,7 @@ public void testRenameMoreThanOnceAcrossSnapDirs_2() throws Exception {
     INodeReference.WithCount barWithCount = (WithCount) barRef.getReferredINode();
     // 5 references: s1, s22, s333, s2222, current tree of sdir1
     assertEquals(5, barWithCount.getReferenceCount());
-    INodeFileWithSnapshot bar = (INodeFileWithSnapshot) barWithCount.asFile();
+    INodeFile bar = barWithCount.asFile();
     List<FileDiff> barDiffs = bar.getDiffs().asList();
     assertEquals(4, barDiffs.size());
     assertEquals("s2222", barDiffs.get(3).snapshot.getRoot().getLocalName());
@@ -1047,7 +1043,7 @@ public void testRenameMoreThanOnceAcrossSnapDirs_2() throws Exception {
     barRef = fsdir.getINode(bar_s2222.toString()).asReference();
     barWithCount = (WithCount) barRef.getReferredINode();
     assertEquals(4, barWithCount.getReferenceCount());
-    bar = (INodeFileWithSnapshot) barWithCount.asFile();
+    bar = barWithCount.asFile();
     barDiffs = bar.getDiffs().asList();
     assertEquals(4, barDiffs.size());
     assertEquals("s2222", barDiffs.get(3).snapshot.getRoot().getLocalName());
@@ -1229,7 +1225,7 @@ public void testRenameAndAppend() throws Exception {
       fooRef = fsdir.getINode4Write(foo2.toString());
       assertTrue(fooRef instanceof INodeReference.DstReference);
       INodeFile fooNode = fooRef.asFile();
-      assertTrue(fooNode instanceof INodeFileWithSnapshot);
+      assertTrue(fooNode.isWithSnapshot());
       assertTrue(fooNode.isUnderConstruction());
     } finally {
       if (out != null) {
@@ -1240,7 +1236,7 @@ public void testRenameAndAppend() throws Exception {
     fooRef = fsdir.getINode4Write(foo2.toString());
     assertTrue(fooRef instanceof INodeReference.DstReference);
     INodeFile fooNode = fooRef.asFile();
-    assertTrue(fooNode instanceof INodeFileWithSnapshot);
+    assertTrue(fooNode.isWithSnapshot());
     assertFalse(fooNode.isUnderConstruction());
     
     restartClusterAndCheckImage(true);
@@ -1715,8 +1711,7 @@ public void testRenameUndo_7() throws Exception {
     assertTrue(diff.getChildrenDiff().getList(ListType.CREATED).isEmpty());
     
     // bar was converted to filewithsnapshot while renaming
-    INodeFileWithSnapshot barNode = (INodeFileWithSnapshot) fsdir
+    INodeFile barNode = fsdir.getINode4Write(bar.toString()).asFile();
-        .getINode4Write(bar.toString());
     assertSame(barNode, children.get(0));
     assertSame(fooNode, barNode.getParent());
     List<FileDiff> barDiffList = barNode.getDiffs().asList();

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

@@ -19,6 +19,7 @@
 
 import static org.apache.hadoop.test.GenericTestUtils.assertExceptionContains;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
@@ -167,7 +168,8 @@ public void testDeletionWithSnapshots() throws Exception {
       Assert.assertSame(INodeFile.class, f1.getClass());
       hdfs.setReplication(file1, (short)2);
       f1 = assertBlockCollection(file1.toString(), 2, fsdir, blockmanager);
-      Assert.assertSame(INodeFileWithSnapshot.class, f1.getClass());
+      assertTrue(f1.isWithSnapshot());
+      assertFalse(f1.isUnderConstruction());
     }
     
     // Check the block information for file0

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

@@ -277,10 +277,10 @@ public void testDeleteCurrentFileDirectory() throws Exception {
     TestSnapshotBlocksMap.assertBlockCollection(new Path(snapshotNoChangeDir,
         noChangeFileSCopy.getLocalName()).toString(), 1, fsdir, blockmanager);
     
-    INodeFileWithSnapshot metaChangeFile2SCopy = 
+    INodeFile metaChangeFile2SCopy = children.get(0).asFile();
-        (INodeFileWithSnapshot) children.get(0);
     assertEquals(metaChangeFile2.getName(), metaChangeFile2SCopy.getLocalName());
-    assertEquals(INodeFileWithSnapshot.class, metaChangeFile2SCopy.getClass());
+    assertTrue(metaChangeFile2SCopy.isWithSnapshot());
+    assertFalse(metaChangeFile2SCopy.isUnderConstruction());
     TestSnapshotBlocksMap.assertBlockCollection(new Path(snapshotNoChangeDir,
         metaChangeFile2SCopy.getLocalName()).toString(), 1, fsdir, blockmanager);
     
@@ -338,8 +338,9 @@ public void testDeleteCurrentFileDirectory() throws Exception {
     INode child = children.get(0);
     assertEquals(child.getLocalName(), metaChangeFile1.getName());
     // check snapshot copy of metaChangeFile1
-    assertEquals(INodeFileWithSnapshot.class, child.getClass());
+    INodeFile metaChangeFile1SCopy = child.asFile();
-    INodeFileWithSnapshot metaChangeFile1SCopy = (INodeFileWithSnapshot) child;
+    assertTrue(metaChangeFile1SCopy.isWithSnapshot());
+    assertFalse(metaChangeFile1SCopy.isUnderConstruction());
     assertEquals(REPLICATION_1,
         metaChangeFile1SCopy.getFileReplication(null));
     assertEquals(REPLICATION_1,