HDFS-4346. Add SequentialNumber as a base class for INodeId and GenerationStamp.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1428167 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -174,6 +174,9 @@ Trunk (Unreleased)
 
     HDFS-4334. Add a unique id to INode.  (Brandon Li via szetszwo)
 
+    HDFS-4346. Add SequentialNumber as a base class for INodeId and
+    GenerationStamp.  (szetszwo)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/GenerationStamp.java

@@ -17,19 +17,18 @@
  */
 package org.apache.hadoop.hdfs.server.common;
 
-import java.util.concurrent.atomic.AtomicLong;
-
 import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.util.SequentialNumber;
 
 /****************************************************************
  * A GenerationStamp is a Hadoop FS primitive, identified by a long.
  ****************************************************************/
 @InterfaceAudience.Private
-public class GenerationStamp implements Comparable<GenerationStamp> {
+public class GenerationStamp extends SequentialNumber {
   /**
-   * The first valid generation stamp.
+   * The last reserved generation stamp.
    */
-  public static final long FIRST_VALID_STAMP = 1000L;
+  public static final long LAST_RESERVED_STAMP = 1000L;
 
   /**
    * Generation stamp of blocks that pre-date the introduction
@@ -37,62 +36,10 @@ public class GenerationStamp implements Comparable<GenerationStamp> {
    */
   public static final long GRANDFATHER_GENERATION_STAMP = 0;
 
-  private AtomicLong genstamp = new AtomicLong();
-
   /**
-   * Create a new instance, initialized to FIRST_VALID_STAMP.
+   * Create a new instance, initialized to {@link #LAST_RESERVED_STAMP}.
    */
   public GenerationStamp() {
-    this(GenerationStamp.FIRST_VALID_STAMP);
-  }
-
-  /**
-   * Create a new instance, initialized to the specified value.
-   */
-  GenerationStamp(long stamp) {
-    genstamp.set(stamp);
-  }
-
-  /**
-   * Returns the current generation stamp
-   */
-  public long getStamp() {
-    return genstamp.get();
-  }
-
-  /**
-   * Sets the current generation stamp
-   */
-  public void setStamp(long stamp) {
-    genstamp.set(stamp);
-  }
-
-  /**
-   * First increments the counter and then returns the stamp 
-   */
-  public long nextStamp() {
-    return genstamp.incrementAndGet();
-  }
-
-  @Override // Comparable
-  public int compareTo(GenerationStamp that) {
-    long stamp1 = this.genstamp.get();
-    long stamp2 = that.genstamp.get();
-    return stamp1 < stamp2 ? -1 :
-           stamp1 > stamp2 ? 1 : 0;
-  }
-
-  @Override // Object
-  public boolean equals(Object o) {
-    if (!(o instanceof GenerationStamp)) {
-      return false;
-    }
-    return compareTo((GenerationStamp)o) == 0;
-  }
-
-  @Override // Object
-  public int hashCode() {
-    long stamp = genstamp.get();
-    return (int) (stamp^(stamp>>>32));
+    super(LAST_RESERVED_STAMP);
   }
 }

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

@@ -378,25 +378,29 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   private INodeId inodeId;
   
   /**
-   * Set the last allocated inode id when fsimage is loaded or editlog is
-   * applied. 
-   * @throws IOException
+   * Set the last allocated inode id when fsimage or editlog is loaded. 
    */
   public void resetLastInodeId(long newValue) throws IOException {
-    inodeId.resetLastInodeId(newValue);
+    try {
+      inodeId.skipTo(newValue);
+    } catch(IllegalStateException ise) {
+      throw new IOException(ise);
+    }
   }
 
   /** Should only be used for tests to reset to any value */
   void resetLastInodeIdWithoutChecking(long newValue) {
-    inodeId.resetLastInodeIdWithoutChecking(newValue);
+    inodeId.setCurrentValue(newValue);
   }
   
+  /** @return the last inode ID. */
   public long getLastInodeId() {
-    return inodeId.getLastInodeId();
+    return inodeId.getCurrentValue();
   }
 
+  /** Allocate a new inode ID. */
   public long allocateNewInodeId() {
-    return inodeId.allocateNewInodeId();
+    return inodeId.nextValue();
   }
   
   /**
@@ -405,9 +409,9 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   void clear() {
     dir.reset();
     dtSecretManager.reset();
-    generationStamp.setStamp(GenerationStamp.FIRST_VALID_STAMP);
+    generationStamp.setCurrentValue(GenerationStamp.LAST_RESERVED_STAMP);
     leaseManager.removeAllLeases();
-    inodeId.resetLastInodeIdWithoutChecking(INodeId.LAST_RESERVED_ID);
+    inodeId.setCurrentValue(INodeId.LAST_RESERVED_ID);
   }
 
   @VisibleForTesting
@@ -2537,8 +2541,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       b.setBlockId(DFSUtil.getRandom().nextLong());
     }
     // Increment the generation stamp for every new block.
-    nextGenerationStamp();
-    b.setGenerationStamp(getGenerationStamp());
+    b.setGenerationStamp(nextGenerationStamp());
     b = dir.addBlock(src, inodesInPath, b, targets);
     NameNode.stateChangeLog.info("BLOCK* allocateBlock: " + src + ". "
         + blockPoolId + " " + b);
@@ -4762,14 +4765,14 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
    * Sets the generation stamp for this filesystem
    */
   void setGenerationStamp(long stamp) {
-    generationStamp.setStamp(stamp);
+    generationStamp.setCurrentValue(stamp);
   }
 
   /**
    * Gets the generation stamp for this filesystem
    */
   long getGenerationStamp() {
-    return generationStamp.getStamp();
+    return generationStamp.getCurrentValue();
   }
 
   /**
@@ -4781,7 +4784,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       throw new SafeModeException(
           "Cannot get next generation stamp", safeMode);
     }
-    long gs = generationStamp.nextStamp();
+    final long gs = generationStamp.nextValue();
     getEditLog().logGenerationStamp(gs);
     // NB: callers sync the log
     return gs;

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

@@ -17,16 +17,14 @@
  */
 package org.apache.hadoop.hdfs.server.namenode;
 
-import java.io.IOException;
-import java.util.concurrent.atomic.AtomicLong;
-
 import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.util.SequentialNumber;
 
 /**
  * An id which uniquely identifies an inode
  */
 @InterfaceAudience.Private
-class INodeId implements Comparable<INodeId> {
+class INodeId extends SequentialNumber {
   /**
    * The last reserved inode id. Reserve id 1 to 1000 for potential future
    * usage. The id won't be recycled and is not expected to wrap around in a
@@ -40,66 +38,7 @@ class INodeId implements Comparable<INodeId> {
    */
   public static final long GRANDFATHER_INODE_ID = 0;
 
-  private AtomicLong lastInodeId = new AtomicLong();
-
-  /**
-   * Create a new instance, initialized to LAST_RESERVED_ID.
-   */
   INodeId() {
-    lastInodeId.set(INodeId.LAST_RESERVED_ID);
-  }
-  
-  /**
-   * Set the last allocated inode id when fsimage is loaded or editlog is
-   * applied.
-   * @throws IOException
-   */
-  void resetLastInodeId(long newValue) throws IOException {
-    if (newValue < getLastInodeId()) {
-      throw new IOException(
-          "Can't reset lastInodeId to be less than its current value "
-              + getLastInodeId() + ", newValue=" + newValue);
-    }
-
-    lastInodeId.set(newValue);
-  }
-
-  void resetLastInodeIdWithoutChecking(long newValue) {
-    lastInodeId.set(newValue);
-  }
-
-  long getLastInodeId() {
-    return lastInodeId.get();
-  }
-
-  /**
-   * First increment the counter and then get the id.
-   */
-  long allocateNewInodeId() {
-    return lastInodeId.incrementAndGet();
-  }
-
-  @Override
-  // Comparable
-  public int compareTo(INodeId that) {
-    long id1 = this.getLastInodeId();
-    long id2 = that.getLastInodeId();
-    return id1 < id2 ? -1 : id1 > id2 ? 1 : 0;
-  }
-
-  @Override
-  // Object
-  public boolean equals(Object o) {
-    if (!(o instanceof INodeId)) {
-      return false;
-    }
-    return compareTo((INodeId) o) == 0;
-  }
-
-  @Override
-  // Object
-  public int hashCode() {
-    long id = getLastInodeId();
-    return (int) (id ^ (id >>> 32));
+    super(LAST_RESERVED_ID);
   }
 }

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

@@ -56,7 +56,7 @@ public class TestBlockInfo {
 
     LOG.info("Building block list...");
     for (int i = 0; i < MAX_BLOCKS; i++) {
-      blockList.add(new Block(i, 0, GenerationStamp.FIRST_VALID_STAMP));
+      blockList.add(new Block(i, 0, GenerationStamp.LAST_RESERVED_STAMP));
       blockInfoList.add(new BlockInfo(blockList.get(i), 3));
       dd.addBlock(blockInfoList.get(i));
 

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

@@ -54,7 +54,7 @@ public class TestComputeInvalidateWork {
         for (int i=0; i<nodes.length; i++) {
           for(int j=0; j<3*blockInvalidateLimit+1; j++) {
             Block block = new Block(i*(blockInvalidateLimit+1)+j, 0, 
-                GenerationStamp.FIRST_VALID_STAMP);
+                GenerationStamp.LAST_RESERVED_STAMP);
             bm.addToInvalidates(block, nodes[i]);
           }
         }

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

@@ -44,7 +44,7 @@ public class TestDatanodeDescriptor {
     DatanodeDescriptor dd = DFSTestUtil.getLocalDatanodeDescriptor();
     ArrayList<Block> blockList = new ArrayList<Block>(MAX_BLOCKS);
     for (int i=0; i<MAX_BLOCKS; i++) {
-      blockList.add(new Block(i, 0, GenerationStamp.FIRST_VALID_STAMP));
+      blockList.add(new Block(i, 0, GenerationStamp.LAST_RESERVED_STAMP));
     }
     dd.addBlocksToBeInvalidated(blockList);
     Block[] bc = dd.getInvalidateBlocks(MAX_LIMIT);

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

@@ -75,7 +75,8 @@ public class TestHeartbeatHandling {
         synchronized(hm) {
           for (int i=0; i<MAX_REPLICATE_BLOCKS; i++) {
             dd.addBlockToBeReplicated(
-                new Block(i, 0, GenerationStamp.FIRST_VALID_STAMP), ONE_TARGET);
+                new Block(i, 0, GenerationStamp.LAST_RESERVED_STAMP),
+                ONE_TARGET);
           }
           DatanodeCommand[] cmds = NameNodeAdapter.sendHeartBeat(nodeReg, dd,
               namesystem).getCommands();
@@ -85,7 +86,7 @@ public class TestHeartbeatHandling {
           
           ArrayList<Block> blockList = new ArrayList<Block>(MAX_INVALIDATE_BLOCKS);
           for (int i=0; i<MAX_INVALIDATE_BLOCKS; i++) {
-            blockList.add(new Block(i, 0, GenerationStamp.FIRST_VALID_STAMP));
+            blockList.add(new Block(i, 0, GenerationStamp.LAST_RESERVED_STAMP));
           }
           dd.addBlocksToBeInvalidated(blockList);
           cmds = NameNodeAdapter.sendHeartBeat(nodeReg, dd, namesystem)

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

@@ -54,7 +54,7 @@ public class CreateEditsLog {
   static final String EDITS_DIR = "/tmp/EditsLogOut";
   static String edits_dir = EDITS_DIR;
   static final public long BLOCK_GENERATION_STAMP =
-    GenerationStamp.FIRST_VALID_STAMP;
+      GenerationStamp.LAST_RESERVED_STAMP;
   
   static void addFiles(FSEditLog editLog, int numFiles, short replication, 
                          int blocksPerFile, long startingBlockId,