svn merge -c -1534417 . for reverting HDFS-4885, which should be committed to trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2832@1534424 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES_HDFS-2832.txt

@@ -36,6 +36,3 @@ IMPROVEMENTS:
 
     HDFS-4988. Datanode must support all the volumes as individual storages.
     (Arpit Agarwal)
-
-    HDFS-4885. Improve the verifyBlockPlacement() API in BlockPlacementPolicy.
-    (Junping Du via szetszwo)

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

@@ -100,17 +100,18 @@ public abstract class BlockPlacementPolicy {
   }
 
   /**
-   * Verify if the block's placement meets requirement of placement policy,
-   * i.e. replicas are placed on no less than minRacks racks in the system.
+   * Verify that the block is replicated on at least minRacks different racks
+   * if there is more than minRacks rack in the system.
    * 
    * @param srcPath the full pathname of the file to be verified
    * @param lBlk block with locations
-   * @param numOfReplicas replica number of file to be verified
-   * @return the result of verification
+   * @param minRacks number of racks the block should be replicated to
+   * @return the difference between the required and the actual number of racks
+   * the block is replicated to.
    */
-  abstract public BlockPlacementStatus verifyBlockPlacement(String srcPath,
-      LocatedBlock lBlk,
-      int numOfReplicas);
+  abstract public int verifyBlockPlacement(String srcPath,
+                                           LocatedBlock lBlk,
+                                           int minRacks);
   /**
    * Decide whether deleting the specified replica of the block still makes 
    * the block conform to the configured block placement policy.

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

@@ -698,22 +698,22 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
   }
 
   @Override
-  public BlockPlacementStatus verifyBlockPlacement(String srcPath,
-      LocatedBlock lBlk, int numberOfReplicas) {
+  public int verifyBlockPlacement(String srcPath,
+                                  LocatedBlock lBlk,
+                                  int minRacks) {
     DatanodeInfo[] locs = lBlk.getLocations();
     if (locs == null)
       locs = DatanodeDescriptor.EMPTY_ARRAY;
     int numRacks = clusterMap.getNumOfRacks();
     if(numRacks <= 1) // only one rack
-      return new BlockPlacementStatusDefault(
-          Math.min(numRacks, numberOfReplicas), numRacks);
-    int minRacks = Math.min(2, numberOfReplicas);
+      return 0;
+    minRacks = Math.min(minRacks, numRacks);
     // 1. Check that all locations are different.
     // 2. Count locations on different racks.
     Set<String> racks = new TreeSet<String>();
     for (DatanodeInfo dn : locs)
       racks.add(dn.getNetworkLocation());
-    return new BlockPlacementStatusDefault(racks.size(), minRacks);
+    return minRacks - racks.size();
   }
 
   @Override

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

@@ -1,42 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.hadoop.hdfs.server.blockmanagement;
-
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.classification.InterfaceStability;
-
-@InterfaceAudience.Private
-@InterfaceStability.Evolving
-public interface BlockPlacementStatus {
-
-  /**
-   * Boolean value to identify if replicas of this block satisfy requirement of 
-   * placement policy
-   * @return if replicas satisfy placement policy's requirement 
-   */
-  public boolean isPlacementPolicySatisfied();
-  
-  /**
-   * Get description info for log or printed in case replicas are failed to meet
-   * requirement of placement policy
-   * @return description in case replicas are failed to meet requirement of
-   * placement policy
-   */
-  public String getErrorDescription();
-
-}

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

@@ -1,44 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.hadoop.hdfs.server.blockmanagement;
-
-public class BlockPlacementStatusDefault implements BlockPlacementStatus {
-
-  private int requiredRacks = 0;
-  private int currentRacks = 0;
-  
-  public BlockPlacementStatusDefault(int currentRacks, int requiredRacks){
-    this.requiredRacks = requiredRacks;
-    this.currentRacks = currentRacks;
-  }
-  
-  @Override
-  public boolean isPlacementPolicySatisfied() {
-    return requiredRacks <= currentRacks;
-  }
-
-  @Override
-  public String getErrorDescription() {
-    if (isPlacementPolicySatisfied()) {
-      return null;
-    }
-    return "Block should be additionally replicated on " + 
-        (requiredRacks - currentRacks) + " more rack(s).";
-  }
-
-}

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

@@ -50,7 +50,6 @@ import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicy;
-import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementStatus;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
 import org.apache.hadoop.hdfs.server.datanode.CachingStrategy;
 import org.apache.hadoop.net.NetUtils;
@@ -375,10 +374,9 @@ public class NamenodeFsck {
                     locs.length + " replica(s).");
       }
       // verify block placement policy
-      BlockPlacementStatus blockPlacementStatus = 
-          BlockPlacementPolicy.getInstance(conf, null, networktopology).
-              verifyBlockPlacement(path, lBlk, targetFileReplication);
-      if (!blockPlacementStatus.isPlacementPolicySatisfied()) {
+      int missingRacks = BlockPlacementPolicy.getInstance(conf, null, networktopology).
+                           verifyBlockPlacement(path, lBlk, Math.min(2,targetFileReplication));
+      if (missingRacks > 0) {
         res.numMisReplicatedBlocks++;
         misReplicatedPerFile++;
         if (!showFiles) {
@@ -387,7 +385,9 @@ public class NamenodeFsck {
           out.print(path + ": ");
         }
         out.println(" Replica placement policy is violated for " + 
-                    block + ". " + blockPlacementStatus.getErrorDescription());
+                    block +
+                    ". Block should be additionally replicated on " + 
+                    missingRacks + " more rack(s).");
       }
       report.append(i + ". " + blkName + " len=" + block.getNumBytes());
       if (locs.length == 0) {

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

@@ -83,6 +83,7 @@ import org.apache.log4j.RollingFileAppender;
 import org.junit.Test;
 
 import com.google.common.collect.Sets;
+import org.mockito.Mockito;
 import static org.mockito.Mockito.*;
 
 /**
@@ -891,80 +892,6 @@ public class TestFsck {
       }
     }
   }
-  
-  /**
-   * Tests that the # of misreplaced replicas is correct
-   * @throws IOException
-   */
-  @Test
-  public void testFsckMisPlacedReplicas() throws IOException {
-    // Desired replication factor
-    final short REPL_FACTOR = 2;
-    // Number of replicas to actually start
-    short NUM_DN = 2;
-    // Number of blocks to write
-    final short NUM_BLOCKS = 3;
-    // Set a small-ish blocksize
-    final long blockSize = 512;
-    
-    String [] racks = {"/rack1", "/rack1"};
-    String [] hosts = {"host1", "host2"};
-    
-    Configuration conf = new Configuration();
-    conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, blockSize);
-    
-    MiniDFSCluster cluster = null;
-    DistributedFileSystem dfs = null;
-    
-    try {
-      // Startup a minicluster
-      cluster = 
-          new MiniDFSCluster.Builder(conf).numDataNodes(NUM_DN).hosts(hosts)
-          .racks(racks).build();
-      assertNotNull("Failed Cluster Creation", cluster);
-      cluster.waitClusterUp();
-      dfs = (DistributedFileSystem) cluster.getFileSystem();
-      assertNotNull("Failed to get FileSystem", dfs);
-      
-      // Create a file that will be intentionally under-replicated
-      final String pathString = new String("/testfile");
-      final Path path = new Path(pathString);
-      long fileLen = blockSize * NUM_BLOCKS;
-      DFSTestUtil.createFile(dfs, path, fileLen, REPL_FACTOR, 1);
-      
-      // Create an under-replicated file
-      NameNode namenode = cluster.getNameNode();
-      NetworkTopology nettop = cluster.getNamesystem().getBlockManager()
-          .getDatanodeManager().getNetworkTopology();
-      // Add a new node on different rack, so previous blocks' replicas 
-      // are considered to be misplaced
-      nettop.add(DFSTestUtil.getDatanodeDescriptor("/rack2", "/host3"));
-      NUM_DN++;
-      
-      Map<String,String[]> pmap = new HashMap<String, String[]>();
-      Writer result = new StringWriter();
-      PrintWriter out = new PrintWriter(result, true);
-      InetAddress remoteAddress = InetAddress.getLocalHost();
-      NamenodeFsck fsck = new NamenodeFsck(conf, namenode, nettop, pmap, out, 
-          NUM_DN, (short)REPL_FACTOR, remoteAddress);
-      
-      // Run the fsck and check the Result
-      final HdfsFileStatus file = 
-          namenode.getRpcServer().getFileInfo(pathString);
-      assertNotNull(file);
-      Result res = new Result(conf);
-      fsck.check(pathString, file, res);
-      // check misReplicatedBlock number.
-      assertEquals(res.numMisReplicatedBlocks, NUM_BLOCKS);
-    } finally {
-      if(dfs != null) {
-        dfs.close();
-      }
-      if(cluster != null) {
-        cluster.shutdown();
-      }
-    }
-  }
 
   /** Test fsck with FileNotFound */
   @Test