HDFS-6072. Clean up dead code of FSImage. Contributed by Haohui Mai.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1576513 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -401,6 +401,8 @@ Release 2.4.0 - UNRELEASED
 
     HDFS-6085. Improve CacheReplicationMonitor log messages a bit (cmccabe)
 
+    HDFS-6072. Clean up dead code of FSImage. (wheat9)
+
   OPTIMIZATIONS
 
     HDFS-5790. LeaseManager.findPath is very slow when many leases need recovery

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/security/token/delegation/DelegationTokenSecretManager.java

@@ -18,16 +18,9 @@
 
 package org.apache.hadoop.hdfs.security.token.delegation;
 
-import java.io.DataInput;
+import com.google.common.base.Preconditions;
-import java.io.DataOutputStream;
+import com.google.common.collect.Lists;
-import java.io.IOException;
+import com.google.protobuf.ByteString;
-import java.io.InterruptedIOException;
-import java.net.InetSocketAddress;
-import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map.Entry;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
@@ -50,9 +43,13 @@ import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.security.token.delegation.AbstractDelegationTokenSecretManager;
 import org.apache.hadoop.security.token.delegation.DelegationKey;
 
-import com.google.common.base.Preconditions;
+import java.io.DataInput;
-import com.google.common.collect.Lists;
+import java.io.IOException;
-import com.google.protobuf.ByteString;
+import java.io.InterruptedIOException;
+import java.net.InetSocketAddress;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map.Entry;
 
 /**
  * A HDFS specific delegation token secret manager.
@@ -214,18 +211,6 @@ public class DelegationTokenSecretManager
     }
   }
 
-  /**
-   * Store the current state of the SecretManager for persistence
-   * 
-   * @param out Output stream for writing into fsimage.
-   * @param sdPath String storage directory path
-   * @throws IOException
-   */
-  public synchronized void saveSecretManagerStateCompat(DataOutputStream out,
-      String sdPath) throws IOException {
-    serializerCompat.save(out, sdPath);
-  }
-
   public synchronized SecretManagerState saveSecretManagerState() {
     SecretManagerSection s = SecretManagerSection.newBuilder()
         .setCurrentId(currentId)
@@ -421,56 +406,6 @@ public class DelegationTokenSecretManager
       loadCurrentTokens(in);
     }
 
-    private void save(DataOutputStream out, String sdPath) throws IOException {
-      out.writeInt(currentId);
-      saveAllKeys(out, sdPath);
-      out.writeInt(delegationTokenSequenceNumber);
-      saveCurrentTokens(out, sdPath);
-    }
-
-    /**
-     * Private helper methods to save delegation keys and tokens in fsimage
-     */
-    private synchronized void saveCurrentTokens(DataOutputStream out,
-        String sdPath) throws IOException {
-      StartupProgress prog = NameNode.getStartupProgress();
-      Step step = new Step(StepType.DELEGATION_TOKENS, sdPath);
-      prog.beginStep(Phase.SAVING_CHECKPOINT, step);
-      prog.setTotal(Phase.SAVING_CHECKPOINT, step, currentTokens.size());
-      Counter counter = prog.getCounter(Phase.SAVING_CHECKPOINT, step);
-      out.writeInt(currentTokens.size());
-      Iterator<DelegationTokenIdentifier> iter = currentTokens.keySet()
-          .iterator();
-      while (iter.hasNext()) {
-        DelegationTokenIdentifier id = iter.next();
-        id.write(out);
-        DelegationTokenInformation info = currentTokens.get(id);
-        out.writeLong(info.getRenewDate());
-        counter.increment();
-      }
-      prog.endStep(Phase.SAVING_CHECKPOINT, step);
-    }
-
-    /*
-     * Save the current state of allKeys
-     */
-    private synchronized void saveAllKeys(DataOutputStream out, String sdPath)
-        throws IOException {
-      StartupProgress prog = NameNode.getStartupProgress();
-      Step step = new Step(StepType.DELEGATION_KEYS, sdPath);
-      prog.beginStep(Phase.SAVING_CHECKPOINT, step);
-      prog.setTotal(Phase.SAVING_CHECKPOINT, step, currentTokens.size());
-      Counter counter = prog.getCounter(Phase.SAVING_CHECKPOINT, step);
-      out.writeInt(allKeys.size());
-      Iterator<Integer> iter = allKeys.keySet().iterator();
-      while (iter.hasNext()) {
-        Integer key = iter.next();
-        allKeys.get(key).write(out);
-        counter.increment();
-      }
-      prog.endStep(Phase.SAVING_CHECKPOINT, step);
-    }
-
     /**
      * Private helper methods to load Delegation tokens from fsimage
      */

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

@@ -27,7 +27,6 @@ import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_PATH_BASED_CACHE
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_PATH_BASED_CACHE_REFRESH_INTERVAL_MS_DEFAULT;
 
 import java.io.DataInput;
-import java.io.DataOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -62,10 +61,10 @@ import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo.Expiration;
 import org.apache.hadoop.hdfs.protocol.CacheDirectiveStats;
 import org.apache.hadoop.hdfs.protocol.CachePoolEntry;
 import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
-import org.apache.hadoop.hdfs.protocol.DatanodeID;
-import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CacheDirectiveInfoProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CachePoolInfoProto;
+import org.apache.hadoop.hdfs.protocol.DatanodeID;
+import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocolPB.PBHelper;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
 import org.apache.hadoop.hdfs.server.blockmanagement.CacheReplicationMonitor;
@@ -952,18 +951,6 @@ public final class CacheManager {
     }
   }
 
-  /**
-   * Saves the current state of the CacheManager to the DataOutput. Used
-   * to persist CacheManager state in the FSImage.
-   * @param out DataOutput to persist state
-   * @param sdPath path of the storage directory
-   * @throws IOException
-   */
-  public void saveStateCompat(DataOutputStream out, String sdPath)
-      throws IOException {
-    serializerCompat.save(out, sdPath);
-  }
-
   public PersistState saveState() throws IOException {
     ArrayList<CachePoolInfoProto> pools = Lists
         .newArrayListWithCapacity(cachePools.size());
@@ -1083,12 +1070,6 @@ public final class CacheManager {
   }
 
   private final class SerializerCompat {
-    private void save(DataOutputStream out, String sdPath) throws IOException {
-      out.writeLong(nextDirectiveId);
-      savePools(out, sdPath);
-      saveDirectives(out, sdPath);
-    }
-
     private void load(DataInput in) throws IOException {
       nextDirectiveId = in.readLong();
       // pools need to be loaded first since directives point to their parent pool
@@ -1096,42 +1077,6 @@ public final class CacheManager {
       loadDirectives(in);
     }
 
-    /**
-     * Save cache pools to fsimage
-     */
-    private void savePools(DataOutputStream out,
-        String sdPath) throws IOException {
-      StartupProgress prog = NameNode.getStartupProgress();
-      Step step = new Step(StepType.CACHE_POOLS, sdPath);
-      prog.beginStep(Phase.SAVING_CHECKPOINT, step);
-      prog.setTotal(Phase.SAVING_CHECKPOINT, step, cachePools.size());
-      Counter counter = prog.getCounter(Phase.SAVING_CHECKPOINT, step);
-      out.writeInt(cachePools.size());
-      for (CachePool pool: cachePools.values()) {
-        FSImageSerialization.writeCachePoolInfo(out, pool.getInfo(true));
-        counter.increment();
-      }
-      prog.endStep(Phase.SAVING_CHECKPOINT, step);
-    }
-
-    /*
-     * Save cache entries to fsimage
-     */
-    private void saveDirectives(DataOutputStream out, String sdPath)
-        throws IOException {
-      StartupProgress prog = NameNode.getStartupProgress();
-      Step step = new Step(StepType.CACHE_ENTRIES, sdPath);
-      prog.beginStep(Phase.SAVING_CHECKPOINT, step);
-      prog.setTotal(Phase.SAVING_CHECKPOINT, step, directivesById.size());
-      Counter counter = prog.getCounter(Phase.SAVING_CHECKPOINT, step);
-      out.writeInt(directivesById.size());
-      for (CacheDirective directive : directivesById.values()) {
-        FSImageSerialization.writeCacheDirectiveInfo(out, directive.toInfo());
-        counter.increment();
-      }
-      prog.endStep(Phase.SAVING_CHECKPOINT, step);
-    }
-
     /**
      * Load cache pools from fsimage
      */

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

@@ -21,20 +21,14 @@ import static org.apache.hadoop.util.Time.now;
 
 import java.io.DataInput;
 import java.io.DataInputStream;
-import java.io.DataOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
-import java.io.FileOutputStream;
 import java.io.IOException;
 import java.security.DigestInputStream;
-import java.security.DigestOutputStream;
 import java.security.MessageDigest;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
 
@@ -56,7 +50,6 @@ import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.StartupOption;
 import org.apache.hadoop.hdfs.server.common.InconsistentFSStateException;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature;
 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.Snapshot;
@@ -67,7 +60,6 @@ import org.apache.hadoop.hdfs.server.namenode.startupprogress.StartupProgress;
 import org.apache.hadoop.hdfs.server.namenode.startupprogress.StartupProgress.Counter;
 import org.apache.hadoop.hdfs.server.namenode.startupprogress.Step;
 import org.apache.hadoop.hdfs.server.namenode.startupprogress.StepType;
-import org.apache.hadoop.hdfs.util.ReadOnlyList;
 import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.io.MD5Hash;
 import org.apache.hadoop.io.Text;
@@ -77,105 +69,8 @@ import com.google.common.base.Preconditions;
 import com.google.common.annotations.VisibleForTesting;
 
 /**
- * Contains inner classes for reading or writing the on-disk format for
+ * This class loads and stores the FSImage of the NameNode. The file
- * FSImages.
+ * src/main/proto/fsimage.proto describes the on-disk layout of the FSImage.
- * 
- * In particular, the format of the FSImage looks like:
- * <pre>
- * FSImage {
- *   layoutVersion: int, namespaceID: int, numberItemsInFSDirectoryTree: long,
- *   namesystemGenerationStampV1: long, namesystemGenerationStampV2: long,
- *   generationStampAtBlockIdSwitch:long, lastAllocatedBlockId:
- *   long transactionID: long, snapshotCounter: int, numberOfSnapshots: int,
- *   numOfSnapshottableDirs: int,
- *   {FSDirectoryTree, FilesUnderConstruction, SecretManagerState} (can be compressed)
- * }
- * 
- * FSDirectoryTree (if {@link Feature#FSIMAGE_NAME_OPTIMIZATION} is supported) {
- *   INodeInfo of root, numberOfChildren of root: int
- *   [list of INodeInfo of root's children],
- *   [list of INodeDirectoryInfo of root's directory children]
- * }
- * 
- * FSDirectoryTree (if {@link Feature#FSIMAGE_NAME_OPTIMIZATION} not supported){
- *   [list of INodeInfo of INodes in topological order]
- * }
- * 
- * INodeInfo {
- *   {
- *     localName: short + byte[]
- *   } when {@link Feature#FSIMAGE_NAME_OPTIMIZATION} is supported
- *   or 
- *   {
- *     fullPath: byte[]
- *   } when {@link Feature#FSIMAGE_NAME_OPTIMIZATION} is not supported
- *   replicationFactor: short, modificationTime: long,
- *   accessTime: long, preferredBlockSize: long,
- *   numberOfBlocks: int (-1 for INodeDirectory, -2 for INodeSymLink),
- *   { 
- *     nsQuota: long, dsQuota: long, 
- *     {
- *       isINodeSnapshottable: byte,
- *       isINodeWithSnapshot: byte (if isINodeSnapshottable is false)
- *     } (when {@link Feature#SNAPSHOT} is supported), 
- *     fsPermission: short, PermissionStatus
- *   } for INodeDirectory
- *   or 
- *   {
- *     symlinkString, fsPermission: short, PermissionStatus
- *   } for INodeSymlink
- *   or
- *   {
- *     [list of BlockInfo]
- *     [list of FileDiff]
- *     {
- *       isINodeFileUnderConstructionSnapshot: byte, 
- *       {clientName: short + byte[], clientMachine: short + byte[]} (when 
- *       isINodeFileUnderConstructionSnapshot is true),
- *     } (when {@link Feature#SNAPSHOT} is supported and writing snapshotINode), 
- *     fsPermission: short, PermissionStatus
- *   } for INodeFile
- * }
- * 
- * INodeDirectoryInfo {
- *   fullPath of the directory: short + byte[],
- *   numberOfChildren: int, [list of INodeInfo of children INode],
- *   {
- *     numberOfSnapshots: int,
- *     [list of Snapshot] (when NumberOfSnapshots is positive),
- *     numberOfDirectoryDiffs: int,
- *     [list of DirectoryDiff] (NumberOfDirectoryDiffs is positive),
- *     number of children that are directories,
- *     [list of INodeDirectoryInfo of the directory children] (includes
- *     snapshot copies of deleted sub-directories)
- *   } (when {@link Feature#SNAPSHOT} is supported), 
- * }
- * 
- * Snapshot {
- *   snapshotID: int, root of Snapshot: INodeDirectoryInfo (its local name is 
- *   the name of the snapshot)
- * }
- * 
- * DirectoryDiff {
- *   full path of the root of the associated Snapshot: short + byte[], 
- *   childrenSize: int, 
- *   isSnapshotRoot: byte, 
- *   snapshotINodeIsNotNull: byte (when isSnapshotRoot is false),
- *   snapshotINode: INodeDirectory (when SnapshotINodeIsNotNull is true), Diff 
- * }
- * 
- * Diff {
- *   createdListSize: int, [Local name of INode in created list],
- *   deletedListSize: int, [INode in deleted list: INodeInfo]
- * }
- *
- * FileDiff {
- *   full path of the root of the associated Snapshot: short + byte[], 
- *   fileSize: long, 
- *   snapshotINodeIsNotNull: byte,
- *   snapshotINode: INodeFile (when SnapshotINodeIsNotNull is true), Diff 
- * }
- * </pre>
  */
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
@@ -683,11 +578,6 @@ public class FSImageFormat {
       }
     }
 
-    /** @return The FSDirectory of the namesystem where the fsimage is loaded */
-    public FSDirectory getFSDirectoryInLoading() {
-      return namesystem.dir;
-    }
-
     public INode loadINodeWithLocalName(boolean isSnapshotINode, DataInput in,
         boolean updateINodeMap) throws IOException {
       return loadINodeWithLocalName(isSnapshotINode, in, updateINodeMap, null);
@@ -920,7 +810,7 @@ public class FSImageFormat {
         if (path != null && FSDirectory.isReservedName(path) && 
             NameNodeLayoutVersion.supports(
                 LayoutVersion.Feature.ADD_INODE_ID, getLayoutVersion())) {
-          // TODO: for HDFS-5428, we use reserved path for those INodeFileUC in 
+          // TODO: for HDFS-5428, we use reserved path for those INodeFileUC in
           // snapshot. If we support INode ID in the layout version, we can use
           // the inode id to find the oldnode.
           oldnode = namesystem.dir.getInode(cons.getId()).asFile();
@@ -1117,7 +1007,7 @@ public class FSImageFormat {
       + " option to automatically rename these paths during upgrade.";
 
   /**
-   * Same as {@link #renameReservedPathsOnUpgrade(String)}, but for a single
+   * Same as {@link #renameReservedPathsOnUpgrade}, but for a single
    * byte array path component.
    */
   private static byte[] renameReservedComponentOnUpgrade(byte[] component,
@@ -1138,7 +1028,7 @@ public class FSImageFormat {
   }
 
   /**
-   * Same as {@link #renameReservedPathsOnUpgrade(String)}, but for a single
+   * Same as {@link #renameReservedPathsOnUpgrade}, but for a single
    * byte array path component.
    */
   private static byte[] renameReservedRootComponentOnUpgrade(byte[] component,
@@ -1160,266 +1050,4 @@ public class FSImageFormat {
     }
     return component;
   }
-
-  /**
-   * A one-shot class responsible for writing an image file.
-   * The write() function should be called once, after which the getter
-   * functions may be used to retrieve information about the file that was written.
-   */
-  static class Saver {
-    private final SaveNamespaceContext context;
-    /** Set to true once an image has been written */
-    private boolean saved = false;
-    
-    /** The MD5 checksum of the file that was written */
-    private MD5Hash savedDigest;
-    private final ReferenceMap referenceMap = new ReferenceMap();
-    
-    private final Map<Long, INodeFile> snapshotUCMap =
-        new HashMap<Long, INodeFile>();
-
-    /** @throws IllegalStateException if the instance has not yet saved an image */
-    private void checkSaved() {
-      if (!saved) {
-        throw new IllegalStateException("FSImageSaver has not saved an image");
-      }
-    }
-    
-    /** @throws IllegalStateException if the instance has already saved an image */
-    private void checkNotSaved() {
-      if (saved) {
-        throw new IllegalStateException("FSImageSaver has already saved an image");
-      }
-    }
-    
-
-    Saver(SaveNamespaceContext context) {
-      this.context = context;
-    }
-
-    /**
-     * Return the MD5 checksum of the image file that was saved.
-     */
-    MD5Hash getSavedDigest() {
-      checkSaved();
-      return savedDigest;
-    }
-
-    void save(File newFile, FSImageCompression compression) throws IOException {
-      checkNotSaved();
-
-      final FSNamesystem sourceNamesystem = context.getSourceNamesystem();
-      final INodeDirectory rootDir = sourceNamesystem.dir.rootDir;
-      final long numINodes = rootDir.getDirectoryWithQuotaFeature()
-          .getSpaceConsumed().get(Quota.NAMESPACE);
-      String sdPath = newFile.getParentFile().getParentFile().getAbsolutePath();
-      Step step = new Step(StepType.INODES, sdPath);
-      StartupProgress prog = NameNode.getStartupProgress();
-      prog.beginStep(Phase.SAVING_CHECKPOINT, step);
-      prog.setTotal(Phase.SAVING_CHECKPOINT, step, numINodes);
-      Counter counter = prog.getCounter(Phase.SAVING_CHECKPOINT, step);
-      long startTime = now();
-      //
-      // Write out data
-      //
-      MessageDigest digester = MD5Hash.getDigester();
-      FileOutputStream fout = new FileOutputStream(newFile);
-      DigestOutputStream fos = new DigestOutputStream(fout, digester);
-      DataOutputStream out = new DataOutputStream(fos);
-      try {
-        out.writeInt(HdfsConstants.NAMENODE_LAYOUT_VERSION);
-        LayoutFlags.write(out);
-        // We use the non-locked version of getNamespaceInfo here since
-        // the coordinating thread of saveNamespace already has read-locked
-        // the namespace for us. If we attempt to take another readlock
-        // from the actual saver thread, there's a potential of a
-        // fairness-related deadlock. See the comments on HDFS-2223.
-        out.writeInt(sourceNamesystem.unprotectedGetNamespaceInfo()
-            .getNamespaceID());
-        out.writeLong(numINodes);
-        out.writeLong(sourceNamesystem.getGenerationStampV1());
-        out.writeLong(sourceNamesystem.getGenerationStampV2());
-        out.writeLong(sourceNamesystem.getGenerationStampAtblockIdSwitch());
-        out.writeLong(sourceNamesystem.getLastAllocatedBlockId());
-        out.writeLong(context.getTxId());
-        out.writeLong(sourceNamesystem.getLastInodeId());
-
-        
-        sourceNamesystem.getSnapshotManager().write(out);
-        
-        // write compression info and set up compressed stream
-        out = compression.writeHeaderAndWrapStream(fos);
-        LOG.info("Saving image file " + newFile +
-                 " using " + compression);
-
-        // save the root
-        saveINode2Image(rootDir, out, false, referenceMap, counter);
-        // save the rest of the nodes
-        saveImage(rootDir, out, true, false, counter);
-        prog.endStep(Phase.SAVING_CHECKPOINT, step);
-        // Now that the step is finished, set counter equal to total to adjust
-        // for possible under-counting due to reference inodes.
-        prog.setCount(Phase.SAVING_CHECKPOINT, step, numINodes);
-        // save files under construction
-        // TODO: for HDFS-5428, since we cannot break the compatibility of 
-        // fsimage, we store part of the under-construction files that are only
-        // in snapshots in this "under-construction-file" section. As a 
-        // temporary solution, we use "/.reserved/.inodes/<inodeid>" as their 
-        // paths, so that when loading fsimage we do not put them into the lease
-        // map. In the future, we can remove this hack when we can bump the 
-        // layout version.
-        sourceNamesystem.saveFilesUnderConstruction(out, snapshotUCMap);
-        
-        context.checkCancelled();
-        sourceNamesystem.saveSecretManagerStateCompat(out, sdPath);
-        context.checkCancelled();
-        sourceNamesystem.getCacheManager().saveStateCompat(out, sdPath);
-        context.checkCancelled();
-        out.flush();
-        context.checkCancelled();
-        fout.getChannel().force(true);
-      } finally {
-        out.close();
-      }
-
-      saved = true;
-      // set md5 of the saved image
-      savedDigest = new MD5Hash(digester.digest());
-
-      LOG.info("Image file " + newFile + " of size " + newFile.length() +
-          " bytes saved in " + (now() - startTime)/1000 + " seconds.");
-    }
-
-    /**
-     * Save children INodes.
-     * @param children The list of children INodes
-     * @param out The DataOutputStream to write
-     * @param inSnapshot Whether the parent directory or its ancestor is in 
-     *                   the deleted list of some snapshot (caused by rename or 
-     *                   deletion)
-     * @param counter Counter to increment for namenode startup progress
-     * @return Number of children that are directory
-     */
-    private int saveChildren(ReadOnlyList<INode> children,
-        DataOutputStream out, boolean inSnapshot, Counter counter)
-        throws IOException {
-      // Write normal children INode. 
-      out.writeInt(children.size());
-      int dirNum = 0;
-      int i = 0;
-      for(INode child : children) {
-        // print all children first
-        // TODO: for HDFS-5428, we cannot change the format/content of fsimage
-        // here, thus even if the parent directory is in snapshot, we still
-        // do not handle INodeUC as those stored in deleted list
-        saveINode2Image(child, out, false, referenceMap, counter);
-        if (child.isDirectory()) {
-          dirNum++;
-        } else if (inSnapshot && child.isFile()
-            && child.asFile().isUnderConstruction()) {
-          this.snapshotUCMap.put(child.getId(), child.asFile());
-        }
-        if (i++ % 50 == 0) {
-          context.checkCancelled();
-        }
-      }
-      return dirNum;
-    }
-    
-    /**
-     * Save file tree image starting from the given root.
-     * This is a recursive procedure, which first saves all children and 
-     * snapshot diffs of a current directory and then moves inside the 
-     * sub-directories.
-     * 
-     * @param current The current node
-     * @param out The DataoutputStream to write the image
-     * @param toSaveSubtree Whether or not to save the subtree to fsimage. For
-     *                      reference node, its subtree may already have been
-     *                      saved before.
-     * @param inSnapshot Whether the current directory is in snapshot
-     * @param counter Counter to increment for namenode startup progress
-     */
-    private void saveImage(INodeDirectory current, DataOutputStream out,
-        boolean toSaveSubtree, boolean inSnapshot, Counter counter)
-        throws IOException {
-      // write the inode id of the directory
-      out.writeLong(current.getId());
-      
-      if (!toSaveSubtree) {
-        return;
-      }
-      
-      final ReadOnlyList<INode> children = current
-          .getChildrenList(Snapshot.CURRENT_STATE_ID);
-      int dirNum = 0;
-      List<INodeDirectory> snapshotDirs = null;
-      DirectoryWithSnapshotFeature sf = current.getDirectoryWithSnapshotFeature();
-      if (sf != null) {
-        snapshotDirs = new ArrayList<INodeDirectory>();
-        sf.getSnapshotDirectory(snapshotDirs);
-        dirNum += snapshotDirs.size();
-      }
-      
-      // 2. Write INodeDirectorySnapshottable#snapshotsByNames to record all
-      // Snapshots
-      if (current instanceof INodeDirectorySnapshottable) {
-        INodeDirectorySnapshottable snapshottableNode = 
-            (INodeDirectorySnapshottable) current;
-        SnapshotFSImageFormat.saveSnapshots(snapshottableNode, out);
-      } else {
-        out.writeInt(-1); // # of snapshots
-      }
-
-      // 3. Write children INode 
-      dirNum += saveChildren(children, out, inSnapshot, counter);
-      
-      // 4. Write DirectoryDiff lists, if there is any.
-      SnapshotFSImageFormat.saveDirectoryDiffList(current, out, referenceMap);
-      
-      // Write sub-tree of sub-directories, including possible snapshots of 
-      // deleted sub-directories
-      out.writeInt(dirNum); // the number of sub-directories
-      for(INode child : children) {
-        if(!child.isDirectory()) {
-          continue;
-        }
-        // make sure we only save the subtree under a reference node once
-        boolean toSave = child.isReference() ? 
-            referenceMap.toProcessSubtree(child.getId()) : true;
-        saveImage(child.asDirectory(), out, toSave, inSnapshot, counter);
-      }
-      if (snapshotDirs != null) {
-        for (INodeDirectory subDir : snapshotDirs) {
-          // make sure we only save the subtree under a reference node once
-          boolean toSave = subDir.getParentReference() != null ? 
-              referenceMap.toProcessSubtree(subDir.getId()) : true;
-          saveImage(subDir, out, toSave, true, counter);
-        }
-      }
-    }
-
-    /**
-     * Saves inode and increments progress counter.
-     * 
-     * @param inode INode to save
-     * @param out DataOutputStream to receive inode
-     * @param writeUnderConstruction boolean true if this is under construction
-     * @param referenceMap ReferenceMap containing reference inodes
-     * @param counter Counter to increment for namenode startup progress
-     * @throws IOException thrown if there is an I/O error
-     */
-    private void saveINode2Image(INode inode, DataOutputStream out,
-        boolean writeUnderConstruction, ReferenceMap referenceMap,
-        Counter counter) throws IOException {
-      FSImageSerialization.saveINode2Image(inode, out, writeUnderConstruction,
-        referenceMap);
-      // Intentionally do not increment counter for reference inodes, because it
-      // is too difficult at this point to assess whether or not this is a
-      // reference that counts toward quota.
-      if (!(inode instanceof INodeReference)) {
-        counter.increment();
-      }
-    }
-  }
 }

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

@@ -17,11 +17,6 @@
  */
 package org.apache.hadoop.hdfs.server.namenode;
 
-import java.io.DataInput;
-import java.io.DataOutput;
-import java.io.DataOutputStream;
-import java.io.IOException;
-
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.fs.Path;
@@ -36,21 +31,20 @@ import org.apache.hadoop.hdfs.protocol.LayoutVersion;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectorySnapshottable;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat.ReferenceMap;
 import org.apache.hadoop.hdfs.util.XMLUtils;
 import org.apache.hadoop.hdfs.util.XMLUtils.InvalidXmlException;
 import org.apache.hadoop.hdfs.util.XMLUtils.Stanza;
 import org.apache.hadoop.io.IntWritable;
 import org.apache.hadoop.io.LongWritable;
 import org.apache.hadoop.io.ShortWritable;
-import org.apache.hadoop.io.Text;
 import org.apache.hadoop.io.WritableUtils;
 import org.xml.sax.ContentHandler;
 import org.xml.sax.SAXException;
 
-import com.google.common.base.Preconditions;
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.DataOutputStream;
+import java.io.IOException;
 
 /**
  * Static utility functions for serializing various pieces of data in the correct
@@ -88,26 +82,6 @@ public class FSImageSerialization {
     final ShortWritable U_SHORT = new ShortWritable();
     final IntWritable U_INT = new IntWritable();
     final LongWritable U_LONG = new LongWritable();
-    final FsPermission FILE_PERM = new FsPermission((short) 0);
-  }
-
-  private static void writePermissionStatus(INodeAttributes inode,
-      DataOutput out) throws IOException {
-    final FsPermission p = TL_DATA.get().FILE_PERM;
-    p.fromShort(inode.getFsPermissionShort());
-    PermissionStatus.write(out, inode.getUserName(), inode.getGroupName(), p);
-  }
-
-  private static void writeBlocks(final Block[] blocks,
-      final DataOutput out) throws IOException {
-    if (blocks == null) {
-      out.writeInt(0);
-    } else {
-      out.writeInt(blocks.length);
-      for (Block blk : blocks) {
-        blk.write(out);
-      }
-    }
   }
 
   // Helper function that reads in an INodeUnderConstruction
@@ -153,183 +127,6 @@ public class FSImageSerialization {
     return file;
   }
 
-  // Helper function that writes an INodeUnderConstruction
-  // into the input stream
-  //
-  static void writeINodeUnderConstruction(DataOutputStream out, INodeFile cons,
-      String path) throws IOException {
-    writeString(path, out);
-    out.writeLong(cons.getId());
-    out.writeShort(cons.getFileReplication());
-    out.writeLong(cons.getModificationTime());
-    out.writeLong(cons.getPreferredBlockSize());
-
-    writeBlocks(cons.getBlocks(), out);
-    cons.getPermissionStatus().write(out);
-
-    FileUnderConstructionFeature uc = cons.getFileUnderConstructionFeature();
-    writeString(uc.getClientName(), out);
-    writeString(uc.getClientMachine(), out);
-
-    out.writeInt(0); //  do not store locations of last block
-  }
-
-  /**
-   * Serialize a {@link INodeFile} node
-   * @param node The node to write
-   * @param out The {@link DataOutputStream} where the fields are written
-   * @param writeBlock Whether to write block information
-   */
-  public static void writeINodeFile(INodeFile file, DataOutput out,
-      boolean writeUnderConstruction) throws IOException {
-    writeLocalName(file, out);
-    out.writeLong(file.getId());
-    out.writeShort(file.getFileReplication());
-    out.writeLong(file.getModificationTime());
-    out.writeLong(file.getAccessTime());
-    out.writeLong(file.getPreferredBlockSize());
-
-    writeBlocks(file.getBlocks(), out);
-    SnapshotFSImageFormat.saveFileDiffList(file, out);
-
-    if (writeUnderConstruction) {
-      if (file.isUnderConstruction()) {
-        out.writeBoolean(true);
-        final FileUnderConstructionFeature uc = file.getFileUnderConstructionFeature();
-        writeString(uc.getClientName(), out);
-        writeString(uc.getClientMachine(), out);
-      } else {
-        out.writeBoolean(false);
-      }
-    }
-
-    writePermissionStatus(file, out);
-  }
-
-  /** Serialize an {@link INodeFileAttributes}. */
-  public static void writeINodeFileAttributes(INodeFileAttributes file,
-      DataOutput out) throws IOException {
-    writeLocalName(file, out);
-    writePermissionStatus(file, out);
-    out.writeLong(file.getModificationTime());
-    out.writeLong(file.getAccessTime());
-
-    out.writeShort(file.getFileReplication());
-    out.writeLong(file.getPreferredBlockSize());
-  }
-
-  private static void writeQuota(Quota.Counts quota, DataOutput out)
-      throws IOException {
-    out.writeLong(quota.get(Quota.NAMESPACE));
-    out.writeLong(quota.get(Quota.DISKSPACE));
-  }
-
-  /**
-   * Serialize a {@link INodeDirectory}
-   * @param node The node to write
-   * @param out The {@link DataOutput} where the fields are written 
-   */
-  public static void writeINodeDirectory(INodeDirectory node, DataOutput out)
-      throws IOException {
-    writeLocalName(node, out);
-    out.writeLong(node.getId());
-    out.writeShort(0);  // replication
-    out.writeLong(node.getModificationTime());
-    out.writeLong(0);   // access time
-    out.writeLong(0);   // preferred block size
-    out.writeInt(-1);   // # of blocks
-
-    writeQuota(node.getQuotaCounts(), out);
-
-    if (node instanceof INodeDirectorySnapshottable) {
-      out.writeBoolean(true);
-    } else {
-      out.writeBoolean(false);
-      out.writeBoolean(node.isWithSnapshot());
-    }
-    
-    writePermissionStatus(node, out);
-  }
-  
-  /**
-   * Serialize a {@link INodeDirectory}
-   * @param a The node to write
-   * @param out The {@link DataOutput} where the fields are written 
-   */
-  public static void writeINodeDirectoryAttributes(
-      INodeDirectoryAttributes a, DataOutput out) throws IOException {
-    writeLocalName(a, out);
-    writePermissionStatus(a, out);
-    out.writeLong(a.getModificationTime());
-    writeQuota(a.getQuotaCounts(), out);
-  }
-
-  /**
-   * Serialize a {@link INodeSymlink} node
-   * @param node The node to write
-   * @param out The {@link DataOutput} where the fields are written
-   */
-  private static void writeINodeSymlink(INodeSymlink node, DataOutput out)
-      throws IOException {
-    writeLocalName(node, out);
-    out.writeLong(node.getId());
-    out.writeShort(0);  // replication
-    out.writeLong(0);   // modification time
-    out.writeLong(0);   // access time
-    out.writeLong(0);   // preferred block size
-    out.writeInt(-2);   // # of blocks
-
-    Text.writeString(out, node.getSymlinkString());
-    writePermissionStatus(node, out);
-  }
-  
-  /** Serialize a {@link INodeReference} node */
-  private static void writeINodeReference(INodeReference ref, DataOutput out,
-      boolean writeUnderConstruction, ReferenceMap referenceMap
-      ) throws IOException {
-    writeLocalName(ref, out);
-    out.writeLong(ref.getId());
-    out.writeShort(0);  // replication
-    out.writeLong(0);   // modification time
-    out.writeLong(0);   // access time
-    out.writeLong(0);   // preferred block size
-    out.writeInt(-3);   // # of blocks
-
-    final boolean isWithName = ref instanceof INodeReference.WithName;
-    out.writeBoolean(isWithName);
-    
-    if (!isWithName) {
-      Preconditions.checkState(ref instanceof INodeReference.DstReference);
-      // dst snapshot id
-      out.writeInt(((INodeReference.DstReference) ref).getDstSnapshotId());
-    } else {
-      out.writeInt(((INodeReference.WithName) ref).getLastSnapshotId());
-    }
-    
-    final INodeReference.WithCount withCount
-        = (INodeReference.WithCount)ref.getReferredINode();
-    referenceMap.writeINodeReferenceWithCount(withCount, out,
-        writeUnderConstruction);
-  }
-
-  /**
-   * Save one inode's attributes to the image.
-   */
-  public static void saveINode2Image(INode node, DataOutput out,
-      boolean writeUnderConstruction, ReferenceMap referenceMap)
-      throws IOException {
-    if (node.isReference()) {
-      writeINodeReference(node.asReference(), out, writeUnderConstruction,
-          referenceMap);
-    } else if (node.isDirectory()) {
-      writeINodeDirectory(node.asDirectory(), out);
-    } else if (node.isSymlink()) {
-      writeINodeSymlink(node.asSymlink(), out);      
-    } else if (node.isFile()) {
-      writeINodeFile(node.asFile(), out, writeUnderConstruction);
-    }
-  }
-
   // This should be reverted to package private once the ImageLoader
   // code is moved into this package. This method should not be called
   // by other code.
@@ -429,12 +226,6 @@ public class FSImageSerialization {
     in.readFully(createdNodeName);
     return createdNodeName;
   }
-
-  private static void writeLocalName(INodeAttributes inode, DataOutput out)
-      throws IOException {
-    final byte[] name = inode.getLocalNameBytes();
-    writeBytes(name, out);
-  }
   
   public static void writeBytes(byte[] data, DataOutput out)
       throws IOException {

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

@@ -6022,42 +6022,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     leaseManager.changeLease(src, dst);
   }
 
-  /**
-   * Serializes leases. 
-   */
-  void saveFilesUnderConstruction(DataOutputStream out,
-      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, 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
-        // snapshotUCMap. We should remove them from the snapshotUCMap.
-        snapshotUCMap.remove(entry.getValue().getId());
-      }
-      
-      out.writeInt(nodes.size() + snapshotUCMap.size()); // write the size    
-      for (Map.Entry<String, INodeFile> entry : nodes.entrySet()) {
-        FSImageSerialization.writeINodeUnderConstruction(
-            out, entry.getValue(), entry.getKey());
-      }
-      for (Map.Entry<Long, INodeFile> entry : snapshotUCMap.entrySet()) {
-        // for those snapshot INodeFileUC, we use "/.reserved/.inodes/<inodeid>"
-        // as their paths
-        StringBuilder b = new StringBuilder();
-        b.append(FSDirectory.DOT_RESERVED_PATH_PREFIX)
-            .append(Path.SEPARATOR).append(FSDirectory.DOT_INODES_STRING)
-            .append(Path.SEPARATOR).append(entry.getValue().getId());
-        FSImageSerialization.writeINodeUnderConstruction(
-            out, entry.getValue(), b.toString());
-      }
-    }
-  }
-
   /**
    * @return all the under-construction files in the lease map
    */
@@ -6333,15 +6297,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     }
     getEditLog().logSync();
   }
-  
-  /**
-   * @param out save state of the secret manager
-   * @param sdPath String storage directory path
-   */
-  void saveSecretManagerStateCompat(DataOutputStream out, String sdPath)
-      throws IOException {
-    dtSecretManager.saveSecretManagerStateCompat(out, sdPath);
-  }
 
   SecretManagerState saveSecretManagerState() {
     return dtSecretManager.saveSecretManagerState();

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

@@ -17,17 +17,13 @@
  */
 package org.apache.hadoop.hdfs.server.namenode.snapshot;
 
-import java.io.DataOutput;
+import com.google.common.base.Preconditions;
-import java.io.IOException;
-import java.util.List;
-
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INode.BlocksMapUpdateInfo;
 import org.apache.hadoop.hdfs.server.namenode.INodeAttributes;
 import org.apache.hadoop.hdfs.server.namenode.Quota;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat.ReferenceMap;
 
-import com.google.common.base.Preconditions;
+import java.util.List;
 
 /**
  * The difference of an inode between in two snapshots.
@@ -133,11 +129,4 @@ abstract class AbstractINodeDiff<N extends INode,
     return getClass().getSimpleName() + ": " + this.getSnapshotId() + " (post="
         + (posteriorDiff == null? null: posteriorDiff.getSnapshotId()) + ")";
   }
-
-  void writeSnapshot(DataOutput out) throws IOException {
-    out.writeInt(snapshotId);
-  }
-  
-  abstract void write(DataOutput out, ReferenceMap referenceMap
-      ) throws IOException;
 }

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

@@ -17,8 +17,6 @@
  */
 package org.apache.hadoop.hdfs.server.namenode.snapshot;
 
-import java.io.DataOutput;
-import java.io.IOException;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -34,7 +32,6 @@ import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
 import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffType;
 import org.apache.hadoop.hdfs.server.namenode.Content;
 import org.apache.hadoop.hdfs.server.namenode.ContentSummaryComputationContext;
-import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INode.BlocksMapUpdateInfo;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
@@ -42,7 +39,6 @@ import org.apache.hadoop.hdfs.server.namenode.INodeDirectoryAttributes;
 import org.apache.hadoop.hdfs.server.namenode.INodeFile;
 import org.apache.hadoop.hdfs.server.namenode.INodeReference;
 import org.apache.hadoop.hdfs.server.namenode.Quota;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat.ReferenceMap;
 import org.apache.hadoop.hdfs.util.Diff;
 import org.apache.hadoop.hdfs.util.Diff.Container;
 import org.apache.hadoop.hdfs.util.Diff.ListType;
@@ -124,35 +120,6 @@ public class DirectoryWithSnapshotFeature implements INode.Feature {
       return counts;
     }
 
-    /** Serialize {@link #created} */
-    private void writeCreated(DataOutput out) throws IOException {
-      final List<INode> created = getList(ListType.CREATED);
-      out.writeInt(created.size());
-      for (INode node : created) {
-        // For INode in created list, we only need to record its local name
-        byte[] name = node.getLocalNameBytes();
-        out.writeShort(name.length);
-        out.write(name);
-      }
-    }
-
-    /** Serialize {@link #deleted} */
-    private void writeDeleted(DataOutput out,
-        ReferenceMap referenceMap) throws IOException {
-      final List<INode> deleted = getList(ListType.DELETED);
-      out.writeInt(deleted.size());
-      for (INode node : deleted) {
-        FSImageSerialization.saveINode2Image(node, out, true, referenceMap);
-      }
-    }
-
-    /** Serialize to out */
-    private void write(DataOutput out, ReferenceMap referenceMap
-        ) throws IOException {
-      writeCreated(out);
-      writeDeleted(out, referenceMap);
-    }
-
     /** Get the list of INodeDirectory contained in the deleted list */
     private void getDirsInDeleted(List<INodeDirectory> dirList) {
       for (INode node : getList(ListType.DELETED)) {
@@ -347,25 +314,6 @@ public class DirectoryWithSnapshotFeature implements INode.Feature {
       return childrenSize;
     }
 
-    @Override
-    void write(DataOutput out, ReferenceMap referenceMap) throws IOException {
-      writeSnapshot(out);
-      out.writeInt(childrenSize);
-
-      // Write snapshotINode
-      out.writeBoolean(isSnapshotRoot);
-      if (!isSnapshotRoot) {
-        if (snapshotINode != null) {
-          out.writeBoolean(true);
-          FSImageSerialization.writeINodeDirectoryAttributes(snapshotINode, out);
-        } else {
-          out.writeBoolean(false);
-        }
-      }
-      // Write diff. Node need to write poseriorDiff, since diffs is a list.
-      diff.write(out, referenceMap);
-    }
-
     @Override
     Quota.Counts destroyDiffAndCollectBlocks(INodeDirectory currentINode,
         BlocksMapUpdateInfo collectedBlocks, final List<INode> removedINodes) {

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

@@ -17,17 +17,13 @@
  */
 package org.apache.hadoop.hdfs.server.namenode.snapshot;
 
-import java.io.DataOutput;
-import java.io.IOException;
-import java.util.List;
-
-import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
 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.Quota;
-import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat.ReferenceMap;
+
+import java.util.List;
 
 /**
  * The difference of an {@link INodeFile} between two snapshots.
@@ -70,20 +66,6 @@ public class FileDiff extends
         + (snapshotINode == null? "?": snapshotINode.getFileReplication());
   }
 
-  @Override
-  void write(DataOutput out, ReferenceMap referenceMap) throws IOException {
-    writeSnapshot(out);
-    out.writeLong(fileSize);
-
-    // write snapshotINode
-    if (snapshotINode != null) {
-      out.writeBoolean(true);
-      FSImageSerialization.writeINodeFileAttributes(snapshotINode, out);
-    } else {
-      out.writeBoolean(false);
-    }
-  }
-
   @Override
   Quota.Counts destroyDiffAndCollectBlocks(INodeFile currentINode,
       BlocksMapUpdateInfo collectedBlocks, final List<INode> removedINodes) {

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

@@ -18,7 +18,6 @@
 package org.apache.hadoop.hdfs.server.namenode.snapshot;
 
 import java.io.DataInput;
-import java.io.DataOutput;
 import java.io.IOException;
 import java.text.SimpleDateFormat;
 import java.util.Arrays;
@@ -31,7 +30,6 @@ import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.server.namenode.AclFeature;
 import org.apache.hadoop.hdfs.server.namenode.FSImageFormat;
-import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
 import org.apache.hadoop.hdfs.util.ReadOnlyList;
@@ -216,11 +214,4 @@ public class Snapshot implements Comparable<byte[]> {
   public String toString() {
     return getClass().getSimpleName() + "." + root.getLocalName() + "(id=" + id + ")";
   }
-  
-  /** Serialize the fields to out */
-  void write(DataOutput out) throws IOException {
-    out.writeInt(id);
-    // write root
-    FSImageSerialization.writeINodeDirectory(root, out);
-  }
 }

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

@@ -29,75 +29,21 @@ import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.server.namenode.FSImageFormat;
 import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
 import org.apache.hadoop.hdfs.server.namenode.INode;
-import org.apache.hadoop.hdfs.server.namenode.INodeAttributes;
 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.INodeFileAttributes;
 import org.apache.hadoop.hdfs.server.namenode.INodeReference;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature.DirectoryDiff;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature.DirectoryDiffList;
 import org.apache.hadoop.hdfs.tools.snapshot.SnapshotDiff;
 import org.apache.hadoop.hdfs.util.Diff.ListType;
-import org.apache.hadoop.hdfs.util.ReadOnlyList;
+import org.apache.hadoop.hdfs.server.namenode.FSImageFormat.Loader;
 
 /**
  * A helper class defining static methods for reading/writing snapshot related
  * information from/to FSImage.
  */
 public class SnapshotFSImageFormat {
-  /**
-   * Save snapshots and snapshot quota for a snapshottable directory.
-   * @param current The directory that the snapshots belongs to.
-   * @param out The {@link DataOutput} to write.
-   * @throws IOException
-   */
-  public static void saveSnapshots(INodeDirectorySnapshottable current,
-      DataOutput out) throws IOException {
-    // list of snapshots in snapshotsByNames
-    ReadOnlyList<Snapshot> snapshots = current.getSnapshotsByNames();
-    out.writeInt(snapshots.size());
-    for (Snapshot s : snapshots) {
-      // write the snapshot id
-      out.writeInt(s.getId());
-    }
-    // snapshot quota
-    out.writeInt(current.getSnapshotQuota());
-  }
-  
-  /**
-   * Save SnapshotDiff list for an INodeDirectoryWithSnapshot.
-   * @param sNode The directory that the SnapshotDiff list belongs to.
-   * @param out The {@link DataOutput} to write.
-   */
-  private static <N extends INode, A extends INodeAttributes, D extends AbstractINodeDiff<N, A, D>>
-      void saveINodeDiffs(final AbstractINodeDiffList<N, A, D> diffs,
-      final DataOutput out, ReferenceMap referenceMap) throws IOException {
-    // Record the diffs in reversed order, so that we can find the correct
-    // reference for INodes in the created list when loading the FSImage
-    if (diffs == null) {
-      out.writeInt(-1); // no diffs
-    } else {
-      final List<D> list = diffs.asList();
-      final int size = list.size();
-      out.writeInt(size);
-      for (int i = size - 1; i >= 0; i--) {
-        list.get(i).write(out, referenceMap);
-      }
-    }
-  }
-  
-  public static void saveDirectoryDiffList(final INodeDirectory dir,
-      final DataOutput out, final ReferenceMap referenceMap
-      ) throws IOException {
-    saveINodeDiffs(dir.getDiffs(), out, referenceMap);
-  }
-  
-  public static void saveFileDiffList(final INodeFile file,
-      final DataOutput out) throws IOException {
-    saveINodeDiffs(file.getDiffs(), out, null);
-  }
-
   public static FileDiffList loadFileDiffList(DataInput in,
       FSImageFormat.Loader loader) throws IOException {
     final int size = in.readInt();
@@ -250,12 +196,12 @@ public class SnapshotFSImageFormat {
       }
     }
   }
-  
+
   /**
    * Load the snapshotINode field of {@link AbstractINodeDiff}.
    * @param snapshot The Snapshot associated with the {@link AbstractINodeDiff}.
    * @param in The {@link DataInput} to read.
-   * @param loader The {@link Loader} instance that this loading procedure is 
+   * @param loader The {@link Loader} instance that this loading procedure is
    *               using.
    * @return The snapshotINode.
    */
@@ -318,23 +264,6 @@ public class SnapshotFSImageFormat {
      * Used to record whether the subtree of the reference node has been saved 
      */
     private final Map<Long, Long> dirMap = new HashMap<Long, Long>();
-
-    public void writeINodeReferenceWithCount(
-        INodeReference.WithCount withCount, DataOutput out,
-        boolean writeUnderConstruction) throws IOException {
-      final INode referred = withCount.getReferredINode();
-      final long id = withCount.getId();
-      final boolean firstReferred = !referenceMap.containsKey(id);
-      out.writeBoolean(firstReferred);
-
-      if (firstReferred) {
-        FSImageSerialization.saveINode2Image(referred, out,
-            writeUnderConstruction, this);
-        referenceMap.put(id, withCount);
-      } else {
-        out.writeLong(id);
-      }
-    }
     
     public boolean toProcessSubtree(long id) {
       if (dirMap.containsKey(id)) {

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

@@ -18,7 +18,6 @@
 package org.apache.hadoop.hdfs.server.namenode.snapshot;
 
 import java.io.DataInput;
-import java.io.DataOutput;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -286,22 +285,6 @@ public class SnapshotManager implements SnapshotStats {
     return snapshottables.values().toArray(
         new INodeDirectorySnapshottable[snapshottables.size()]);
   }
-
-  /**
-   * Write {@link #snapshotCounter}, {@link #numSnapshots},
-   * and all snapshots to the DataOutput.
-   */
-  public void write(DataOutput out) throws IOException {
-    out.writeInt(snapshotCounter);
-    out.writeInt(numSnapshots.get());
-
-    // write all snapshots.
-    for(INodeDirectorySnapshottable snapshottableDir : snapshottables.values()) {
-      for(Snapshot s : snapshottableDir.getSnapshotsByNames()) {
-        s.write(out);
-      }
-    }
-  }
   
   /**
    * Read values of {@link #snapshotCounter}, {@link #numSnapshots}, and