HDFS-8404. Pending block replication can get stuck using older gensta…

…mp. Contributed by Nathan Roberts.

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

@@ -878,6 +878,9 @@ Release 2.7.1 - UNRELEASED
 
  HDFS-8405. Fix a typo in NamenodeFsck. (Takanobu Asanuma via szetszwo)
 
+ HDFS-8404. Pending block replication can get stuck using older genstamp
+ (Nathan Roberts via kihwal)
+
 Release 2.7.0 - 2015-04-20
 
  INCOMPATIBLE CHANGES

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

@@ -1690,13 +1690,18 @@ private void processPendingReplications() {
  namesystem.writeLock();
  try {
  for (int i = 0; i < timedOutItems.length; i++) {
+ /*
+ * Use the blockinfo from the blocksmap to be certain we're working
+ * with the most up-to-date block information (e.g. genstamp).
+ */
+ BlockInfoContiguous bi = blocksMap.getStoredBlock(timedOutItems[i]);
+ if (bi == null) {
+ continue;
+ }
  NumberReplicas num = countNodes(timedOutItems[i]);
- if (isNeededReplication(timedOutItems[i], getReplication(timedOutItems[i]),
- num.liveReplicas())) {
- neededReplications.add(timedOutItems[i],
- num.liveReplicas(),
- num.decommissionedAndDecommissioning(),
- getReplication(timedOutItems[i]));
+ if (isNeededReplication(bi, getReplication(bi), num.liveReplicas())) {
+ neededReplications.add(bi, num.liveReplicas(),
+ num.decommissionedAndDecommissioning(), getReplication(bi));
  }
  }
  } finally {

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

@@ -42,6 +42,7 @@
 import org.apache.hadoop.hdfs.server.protocol.ReceivedDeletedBlockInfo.BlockStatus;
 import org.apache.hadoop.hdfs.server.protocol.StorageReceivedDeletedBlocks;
 import org.junit.Test;
+import org.mockito.Mockito;
 
 /**
  * This class tests the internals of PendingReplicationBlocks.java,
@@ -52,13 +53,11 @@ public class TestPendingReplication {
  private static final int DFS_REPLICATION_INTERVAL = 1;
  // Number of datanodes in the cluster
  private static final int DATANODE_COUNT = 5;
-
  @Test
  public void testPendingReplication() {
  PendingReplicationBlocks pendingReplications;
  pendingReplications = new PendingReplicationBlocks(TIMEOUT * 1000);
  pendingReplications.start();
-
  //
  // Add 10 blocks to pendingReplications.
  //
@@ -140,15 +139,106 @@ public void testPendingReplication() {
  //
  // Verify that everything has timed out.
  //
- assertEquals("Size of pendingReplications ",
- 0, pendingReplications.size());
+ assertEquals("Size of pendingReplications ", 0, pendingReplications.size());
  Block[] timedOut = pendingReplications.getTimedOutBlocks();
  assertTrue(timedOut != null && timedOut.length == 15);
  for (int i = 0; i < timedOut.length; i++) {
  assertTrue(timedOut[i].getBlockId() < 15);
  }
  pendingReplications.stop();
  }
+
+/* Test that processPendingReplications will use the most recent
+ * blockinfo from the blocksmap by placing a larger genstamp into
+ * the blocksmap.
+ */
+ @Test
+ public void testProcessPendingReplications() throws Exception {
+ final Configuration conf = new HdfsConfiguration();
+ conf.setLong(
+ DFSConfigKeys.DFS_NAMENODE_REPLICATION_PENDING_TIMEOUT_SEC_KEY, TIMEOUT);
+ MiniDFSCluster cluster = null;
+ Block block;
+ BlockInfoContiguous blockInfo;
+ try {
+ cluster =
+ new MiniDFSCluster.Builder(conf).numDataNodes(DATANODE_COUNT).build();
+ cluster.waitActive();
+
+ FSNamesystem fsn = cluster.getNamesystem();
+ BlockManager blkManager = fsn.getBlockManager();
+
+ PendingReplicationBlocks pendingReplications =
+ blkManager.pendingReplications;
+ UnderReplicatedBlocks neededReplications = blkManager.neededReplications;
+ BlocksMap blocksMap = blkManager.blocksMap;
+
+ //
+ // Add 1 block to pendingReplications with GenerationStamp = 0.
+ //
+
+ block = new Block(1, 1, 0);
+ blockInfo = new BlockInfoContiguous(block, (short) 3);
+
+ pendingReplications.increment(block,
+ DatanodeStorageInfo.toDatanodeDescriptors(
+ DFSTestUtil.createDatanodeStorageInfos(1)));
+ BlockCollection bc = Mockito.mock(BlockCollection.class);
+ Mockito.doReturn((short) 3).when(bc).getPreferredBlockReplication();
+ // Place into blocksmap with GenerationStamp = 1
+ blockInfo.setGenerationStamp(1);
+ blocksMap.addBlockCollection(blockInfo, bc);
+
+ assertEquals("Size of pendingReplications ", 1,
+ pendingReplications.size());
+
+ // Add a second block to pendingReplications that has no
+ // corresponding entry in blocksmap
+ block = new Block(2, 2, 0);
+ pendingReplications.increment(block,
+ DatanodeStorageInfo.toDatanodeDescriptors(
+ DFSTestUtil.createDatanodeStorageInfos(1)));
+
+ // verify 2 blocks in pendingReplications
+ assertEquals("Size of pendingReplications ", 2,
+ pendingReplications.size());
+
+ //
+ // Wait for everything to timeout.
+ //
+ while (pendingReplications.size() > 0) {
+ try {
+ Thread.sleep(100);
+ } catch (Exception e) {
+ }
+ }
+
+ //
+ // Verify that block moves to neededReplications
+ //
+ while (neededReplications.size() == 0) {
+ try {
+ Thread.sleep(100);
+ } catch (Exception e) {
+ }
+ }
+
+ // Verify that the generation stamp we will try to replicate
+ // is now 1
+ for (Block b: neededReplications) {
+ assertEquals("Generation stamp is 1 ", 1,
+ b.getGenerationStamp());
+ }
+
+ // Verify size of neededReplications is exactly 1.
+ assertEquals("size of neededReplications is 1 ", 1,
+ neededReplications.size());
+ } finally {
+ if (cluster != null) {
+ cluster.shutdown();
+ }
+ }
+ }
 
  /**
  * Test if DatanodeProtocol#blockReceivedAndDeleted can correctly update the