HDFS-8769. Erasure coding: unit test for SequentialBlockGroupIdGenerator. Contributed by Rakesh R.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/LocatedStripedBlock.java

@@ -63,7 +63,7 @@ public class LocatedStripedBlock extends LocatedBlock {
         + "; corrupt=" + isCorrupt()
         + "; offset=" + getStartOffset()
         + "; locs=" + Arrays.asList(getLocations())
-        + "; indices=" + Arrays.asList(blockIndices)
+        + "; indices=" + Arrays.toString(blockIndices)
         + "}";
   }
 

hadoop-hdfs-project/hadoop-hdfs/CHANGES-HDFS-EC-7285.txt

@@ -376,3 +376,6 @@
 
     HDFS-8798. Erasure Coding: fix DFSStripedInputStream/DFSStripedOutputStream
     re-fetch token when expired. (Walter Su via jing9)
+
+    HDFS-8769. Erasure coding: unit test for SequentialBlockGroupIdGenerator.
+    (Rakesh R via waltersu4549)

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

@@ -248,4 +248,8 @@ public class BlockIdManager {
     return (int) (reportedBlock.getBlockId() &
         HdfsServerConstants.BLOCK_GROUP_INDEX_MASK);
   }
+
+  SequentialBlockGroupIdGenerator getBlockGroupIdGenerator() {
+    return blockGroupIdGenerator;
+  }
 }

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

@@ -0,0 +1,222 @@
+/**
+ * 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 static org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BLOCK_GROUP_INDEX_MASK;
+import static org.apache.hadoop.hdfs.server.common.HdfsServerConstants.MAX_BLOCKS_IN_GROUP;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.not;
+import static org.junit.Assert.assertThat;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.spy;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.DFSTestUtil;
+import org.apache.hadoop.hdfs.HdfsConfiguration;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants;
+import org.apache.hadoop.hdfs.protocol.LocatedBlock;
+import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
+import org.apache.hadoop.test.GenericTestUtils;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.internal.util.reflection.Whitebox;
+import org.mockito.stubbing.Answer;
+
+/**
+ * Tests the sequential blockGroup ID generation mechanism and blockGroup ID
+ * collision handling.
+ */
+public class TestSequentialBlockGroupId {
+  private static final Log LOG = LogFactory
+      .getLog("TestSequentialBlockGroupId");
+
+  private final short REPLICATION = 1;
+  private final long SEED = 0;
+  private final int dataBlocks = HdfsConstants.NUM_DATA_BLOCKS;
+  private final int parityBlocks = HdfsConstants.NUM_PARITY_BLOCKS;
+  private final int cellSize = HdfsConstants.BLOCK_STRIPED_CELL_SIZE;
+
+  private final int stripesPerBlock = 2;
+  private final int blockSize = cellSize * stripesPerBlock;
+  private final int numDNs = dataBlocks + parityBlocks + 2;
+  private final int blockGrpCount = 4;
+  private final int fileLen = blockSize * dataBlocks * blockGrpCount;
+
+  private MiniDFSCluster cluster;
+  private FileSystem fs;
+  private SequentialBlockGroupIdGenerator blockGrpIdGenerator;
+  private Path eczone = new Path("/eczone");
+
+  @Before
+  public void setup() throws Exception {
+    Configuration conf = new HdfsConfiguration();
+    conf.setInt(DFSConfigKeys.DFS_REPLICATION_KEY, 1);
+    conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, blockSize);
+    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(numDNs).build();
+    cluster.waitActive();
+
+    fs = cluster.getFileSystem();
+    blockGrpIdGenerator = cluster.getNamesystem().getBlockIdManager()
+        .getBlockGroupIdGenerator();
+    fs.mkdirs(eczone);
+    cluster.getFileSystem().getClient()
+        .createErasureCodingZone("/eczone", null, cellSize);
+  }
+
+  @After
+  public void teardown() {
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  /**
+   * Test that blockGroup IDs are generating unique value.
+   */
+  @Test(timeout = 60000)
+  public void testBlockGroupIdGeneration() throws IOException {
+    long blockGroupIdInitialValue = blockGrpIdGenerator.getCurrentValue();
+
+    // Create a file that is 4 blocks long.
+    Path path = new Path(eczone, "testBlockGrpIdGeneration.dat");
+    DFSTestUtil.createFile(fs, path, cellSize, fileLen, blockSize, REPLICATION,
+        SEED);
+    List<LocatedBlock> blocks = DFSTestUtil.getAllBlocks(fs, path);
+    assertThat("Wrong BlockGrps", blocks.size(), is(blockGrpCount));
+
+    // initialising the block group generator for verifying the block id
+    blockGrpIdGenerator.setCurrentValue(blockGroupIdInitialValue);
+    // Ensure that the block IDs are generating unique value.
+    for (int i = 0; i < blocks.size(); ++i) {
+      blockGrpIdGenerator
+          .skipTo((blockGrpIdGenerator.getCurrentValue() & ~BLOCK_GROUP_INDEX_MASK)
+              + MAX_BLOCKS_IN_GROUP);
+      long nextBlockExpectedId = blockGrpIdGenerator.getCurrentValue();
+      long nextBlockGrpId = blocks.get(i).getBlock().getBlockId();
+      LOG.info("BlockGrp" + i + " id is " + nextBlockGrpId);
+      assertThat("BlockGrpId mismatches!", nextBlockGrpId,
+          is(nextBlockExpectedId));
+    }
+  }
+
+  /**
+   * Test that collisions in the blockGroup ID space are handled gracefully.
+   */
+  @Test(timeout = 60000)
+  public void testTriggerBlockGroupIdCollision() throws IOException {
+    long blockGroupIdInitialValue = blockGrpIdGenerator.getCurrentValue();
+
+    // Create a file with a few blocks to rev up the global block ID
+    // counter.
+    Path path1 = new Path(eczone, "testBlockGrpIdCollisionDetection_file1.dat");
+    DFSTestUtil.createFile(fs, path1, cellSize, fileLen, blockSize,
+        REPLICATION, SEED);
+    List<LocatedBlock> blocks1 = DFSTestUtil.getAllBlocks(fs, path1);
+    assertThat("Wrong BlockGrps", blocks1.size(), is(blockGrpCount));
+
+    // Rewind the block ID counter in the name system object. This will result
+    // in block ID collisions when we try to allocate new blocks.
+    blockGrpIdGenerator.setCurrentValue(blockGroupIdInitialValue);
+
+    // Trigger collisions by creating a new file.
+    Path path2 = new Path(eczone, "testBlockGrpIdCollisionDetection_file2.dat");
+    DFSTestUtil.createFile(fs, path2, cellSize, fileLen, blockSize,
+        REPLICATION, SEED);
+    List<LocatedBlock> blocks2 = DFSTestUtil.getAllBlocks(fs, path2);
+    assertThat("Wrong BlockGrps", blocks2.size(), is(blockGrpCount));
+
+    // Make sure that file1 and file2 block IDs are different
+    for (LocatedBlock locBlock1 : blocks1) {
+      long blockId1 = locBlock1.getBlock().getBlockId();
+      for (LocatedBlock locBlock2 : blocks2) {
+        long blockId2 = locBlock2.getBlock().getBlockId();
+        assertThat("BlockGrpId mismatches!", blockId1, is(not(blockId2)));
+      }
+    }
+  }
+
+  /**
+   * Test that collisions in the blockGroup ID when the id is occupied by legacy
+   * block.
+   */
+  @Test(timeout = 60000)
+  public void testTriggerBlockGroupIdCollisionWithLegacyBlockId()
+      throws Exception {
+    long blockGroupIdInitialValue = blockGrpIdGenerator.getCurrentValue();
+    blockGrpIdGenerator
+        .skipTo((blockGrpIdGenerator.getCurrentValue() & ~BLOCK_GROUP_INDEX_MASK)
+            + MAX_BLOCKS_IN_GROUP);
+    final long curBlockGroupIdValue = blockGrpIdGenerator.getCurrentValue();
+
+    // Creates contiguous block with negative blockId so that it would trigger
+    // collision during blockGroup Id generation
+    FSNamesystem fsn = cluster.getNamesystem();
+    // Replace SequentialBlockIdGenerator with a spy
+    SequentialBlockIdGenerator blockIdGenerator = spy(fsn.getBlockIdManager()
+        .getBlockIdGenerator());
+    Whitebox.setInternalState(fsn.getBlockIdManager(), "blockIdGenerator",
+        blockIdGenerator);
+    SequentialBlockIdGenerator spySequentialBlockIdGenerator = new SequentialBlockIdGenerator(
+        null) {
+      @Override
+      public long nextValue() {
+        return curBlockGroupIdValue;
+      }
+    };
+    final Answer<Object> delegator = new GenericTestUtils.DelegateAnswer(
+        spySequentialBlockIdGenerator);
+    doAnswer(delegator).when(blockIdGenerator).nextValue();
+
+    Path path1 = new Path("/testCollisionWithLegacyBlock_file1.dat");
+    DFSTestUtil.createFile(fs, path1, 1024, REPLICATION, SEED);
+
+    List<LocatedBlock> contiguousBlocks = DFSTestUtil.getAllBlocks(fs, path1);
+    assertThat(contiguousBlocks.size(), is(1));
+    Assert.assertEquals("Unexpected BlockId!", curBlockGroupIdValue,
+        contiguousBlocks.get(0).getBlock().getBlockId());
+
+    // Reset back to the initial value to trigger collision
+    blockGrpIdGenerator.setCurrentValue(blockGroupIdInitialValue);
+    // Trigger collisions by creating a new file.
+    Path path2 = new Path(eczone, "testCollisionWithLegacyBlock_file2.dat");
+    DFSTestUtil.createFile(fs, path2, cellSize, fileLen, blockSize,
+        REPLICATION, SEED);
+    List<LocatedBlock> blocks2 = DFSTestUtil.getAllBlocks(fs, path2);
+    assertThat("Wrong BlockGrps", blocks2.size(), is(blockGrpCount));
+
+    // Make sure that file1 and file2 block IDs are different
+    for (LocatedBlock locBlock1 : contiguousBlocks) {
+      long blockId1 = locBlock1.getBlock().getBlockId();
+      for (LocatedBlock locBlock2 : blocks2) {
+        long blockId2 = locBlock2.getBlock().getBlockId();
+        assertThat("BlockGrpId mismatches!", blockId1, is(not(blockId2)));
+      }
+    }
+  }
+}