private int getTrueReplication(MiniDFSCluster cluster, ExtendedBlock block) throws IOException {
   int count = 0;
   for (DataNode dn : cluster.getDataNodes()) {
     if (DataNodeTestUtils.getFSDataset(dn)
             .getStoredBlock(block.getBlockPoolId(), block.getBlockId())
         != null) {
       count++;
     }
   }
   return count;
 }
  // test writeToRbw
  @Test
  public void testWriteToRbw() throws Exception {
    MiniDFSCluster cluster = new MiniDFSCluster.Builder(new HdfsConfiguration()).build();
    try {
      cluster.waitActive();
      DataNode dn = cluster.getDataNodes().get(0);
      FsDatasetImpl dataSet = (FsDatasetImpl) DataNodeTestUtils.getFSDataset(dn);

      // set up replicasMap
      String bpid = cluster.getNamesystem().getBlockPoolId();
      ExtendedBlock[] blocks = setup(bpid, dataSet);

      // test writeToRbw
      testWriteToRbw(dataSet, blocks);
    } finally {
      cluster.shutdown();
    }
  }
  /**
   * The following test first creates a file with a few blocks. It randomly truncates the replica of
   * the last block stored in each datanode. Finally, it triggers block synchronization to
   * synchronize all stored block.
   */
  public void testBlockSynchronization() throws Exception {
    final int ORG_FILE_SIZE = 3000;
    Configuration conf = new HdfsConfiguration();
    conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, BLOCK_SIZE);
    MiniDFSCluster cluster = null;

    try {
      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(5).build();
      cluster.waitActive();

      // create a file
      DistributedFileSystem dfs = (DistributedFileSystem) cluster.getFileSystem();
      String filestr = "/foo";
      Path filepath = new Path(filestr);
      DFSTestUtil.createFile(dfs, filepath, ORG_FILE_SIZE, REPLICATION_NUM, 0L);
      assertTrue(dfs.exists(filepath));
      DFSTestUtil.waitReplication(dfs, filepath, REPLICATION_NUM);

      // get block info for the last block
      LocatedBlock locatedblock =
          TestInterDatanodeProtocol.getLastLocatedBlock(dfs.dfs.getNamenode(), filestr);
      DatanodeInfo[] datanodeinfos = locatedblock.getLocations();
      assertEquals(REPLICATION_NUM, datanodeinfos.length);

      // connect to data nodes
      DataNode[] datanodes = new DataNode[REPLICATION_NUM];
      for (int i = 0; i < REPLICATION_NUM; i++) {
        datanodes[i] = cluster.getDataNode(datanodeinfos[i].getIpcPort());
        assertTrue(datanodes[i] != null);
      }

      // verify Block Info
      ExtendedBlock lastblock = locatedblock.getBlock();
      DataNode.LOG.info("newblocks=" + lastblock);
      for (int i = 0; i < REPLICATION_NUM; i++) {
        checkMetaInfo(lastblock, datanodes[i]);
      }

      DataNode.LOG.info("dfs.dfs.clientName=" + dfs.dfs.clientName);
      cluster.getNameNodeRpc().append(filestr, dfs.dfs.clientName);

      // expire lease to trigger block recovery.
      waitLeaseRecovery(cluster);

      Block[] updatedmetainfo = new Block[REPLICATION_NUM];
      long oldSize = lastblock.getNumBytes();
      lastblock =
          TestInterDatanodeProtocol.getLastLocatedBlock(dfs.dfs.getNamenode(), filestr).getBlock();
      long currentGS = lastblock.getGenerationStamp();
      for (int i = 0; i < REPLICATION_NUM; i++) {
        updatedmetainfo[i] =
            DataNodeTestUtils.getFSDataset(datanodes[i])
                .getStoredBlock(lastblock.getBlockPoolId(), lastblock.getBlockId());
        assertEquals(lastblock.getBlockId(), updatedmetainfo[i].getBlockId());
        assertEquals(oldSize, updatedmetainfo[i].getNumBytes());
        assertEquals(currentGS, updatedmetainfo[i].getGenerationStamp());
      }

      // verify that lease recovery does not occur when namenode is in safemode
      System.out.println("Testing that lease recovery cannot happen during safemode.");
      filestr = "/foo.safemode";
      filepath = new Path(filestr);
      dfs.create(filepath, (short) 1);
      cluster.getNameNodeRpc().setSafeMode(HdfsConstants.SafeModeAction.SAFEMODE_ENTER);
      assertTrue(dfs.dfs.exists(filestr));
      DFSTestUtil.waitReplication(dfs, filepath, (short) 1);
      waitLeaseRecovery(cluster);
      // verify that we still cannot recover the lease
      LeaseManager lm = NameNodeAdapter.getLeaseManager(cluster.getNamesystem());
      assertTrue("Found " + lm.countLease() + " lease, expected 1", lm.countLease() == 1);
      cluster.getNameNodeRpc().setSafeMode(HdfsConstants.SafeModeAction.SAFEMODE_LEAVE);
    } finally {
      if (cluster != null) {
        cluster.shutdown();
      }
    }
  }
  /** Test for {@link FsDatasetImpl#updateReplicaUnderRecovery(ExtendedBlock, long, long)} */
  @Test
  public void testUpdateReplicaUnderRecovery() throws IOException {
    MiniDFSCluster cluster = null;

    try {
      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(3).build();
      cluster.waitActive();
      String bpid = cluster.getNamesystem().getBlockPoolId();

      // create a file
      DistributedFileSystem dfs = (DistributedFileSystem) cluster.getFileSystem();
      String filestr = "/foo";
      Path filepath = new Path(filestr);
      DFSTestUtil.createFile(dfs, filepath, 1024L, (short) 3, 0L);

      // get block info
      final LocatedBlock locatedblock =
          getLastLocatedBlock(DFSClientAdapter.getDFSClient(dfs).getNamenode(), filestr);
      final DatanodeInfo[] datanodeinfo = locatedblock.getLocations();
      Assert.assertTrue(datanodeinfo.length > 0);

      // get DataNode and FSDataset objects
      final DataNode datanode = cluster.getDataNode(datanodeinfo[0].getIpcPort());
      Assert.assertTrue(datanode != null);

      // initReplicaRecovery
      final ExtendedBlock b = locatedblock.getBlock();
      final long recoveryid = b.getGenerationStamp() + 1;
      final long newlength = b.getNumBytes() - 1;
      final FsDatasetSpi<?> fsdataset = DataNodeTestUtils.getFSDataset(datanode);
      final ReplicaRecoveryInfo rri =
          fsdataset.initReplicaRecovery(new RecoveringBlock(b, null, recoveryid));

      // check replica
      final ReplicaInfo replica =
          FsDatasetTestUtil.fetchReplicaInfo(fsdataset, bpid, b.getBlockId());
      Assert.assertEquals(ReplicaState.RUR, replica.getState());

      // check meta data before update
      FsDatasetImpl.checkReplicaFiles(replica);

      // case "THIS IS NOT SUPPOSED TO HAPPEN"
      // with (block length) != (stored replica's on disk length).
      {
        // create a block with same id and gs but different length.
        final ExtendedBlock tmp =
            new ExtendedBlock(
                b.getBlockPoolId(),
                rri.getBlockId(),
                rri.getNumBytes() - 1,
                rri.getGenerationStamp());
        try {
          // update should fail
          fsdataset.updateReplicaUnderRecovery(tmp, recoveryid, newlength);
          Assert.fail();
        } catch (IOException ioe) {
          System.out.println("GOOD: getting " + ioe);
        }
      }

      // update
      final String storageID =
          fsdataset.updateReplicaUnderRecovery(
              new ExtendedBlock(b.getBlockPoolId(), rri), recoveryid, newlength);
      assertTrue(storageID != null);

    } finally {
      if (cluster != null) cluster.shutdown();
    }
  }
 public static void checkMetaInfo(ExtendedBlock b, DataNode dn) throws IOException {
   Block metainfo =
       DataNodeTestUtils.getFSDataset(dn).getStoredBlock(b.getBlockPoolId(), b.getBlockId());
   Assert.assertEquals(b.getBlockId(), metainfo.getBlockId());
   Assert.assertEquals(b.getNumBytes(), metainfo.getNumBytes());
 }