HDFS-16999. Fix wrong use of processFirstBlockReport(). (#5622). Contributed by Shuyan Zhang.

Signed-off-by: Ayush Saxena <ayushsaxena@apache.org>
Signed-off-by: He Xiaoqiao <hexiaoqiao@apache.org>

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

@@ -2913,7 +2913,7 @@ public class BlockManager implements BlockStatsMXBean {
         return !node.hasStaleStorages();
       }
 
-      if (storageInfo.getBlockReportCount() == 0) {
+      if (!storageInfo.hasReceivedBlockReport()) {
         // The first block report can be processed a lot more efficiently than
         // ordinary block reports.  This shortens restart times.
         blockLog.info("BLOCK* processReport 0x{} with lease ID 0x{}: Processing first "

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

@@ -128,6 +128,10 @@ public class DatanodeStorageInfo {
   /** The number of block reports received */
   private int blockReportCount = 0;
 
+  /** Whether the NameNode has received block reports for this storage since it
+   * was started.*/
+  private boolean hasReceivedBlockReport = false;
+
   /**
    * Set to false on any NN failover, and reset to true
    * whenever a block report is received.
@@ -160,6 +164,10 @@ public class DatanodeStorageInfo {
     return blockReportCount;
   }
 
+  boolean hasReceivedBlockReport() {
+    return hasReceivedBlockReport;
+  }
+
   void setBlockReportCount(int blockReportCount) {
     this.blockReportCount = blockReportCount;
   }
@@ -188,6 +196,7 @@ public class DatanodeStorageInfo {
       blockContentsStale = false;
     }
     blockReportCount++;
+    hasReceivedBlockReport = true;
   }
 
   @VisibleForTesting

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeImpl.java

@@ -350,7 +350,7 @@ public class FsVolumeImpl implements FsVolumeSpi {
   }
 
   @VisibleForTesting
-  File getCurrentDir() {
+  public File getCurrentDir() {
     return currentDir;
   }
 

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

@@ -17,6 +17,9 @@
  */
 package org.apache.hadoop.hdfs.server.blockmanagement;
 
+import org.apache.hadoop.fs.BlockLocation;
+import org.apache.hadoop.fs.FileStatus;
+import org.apache.hadoop.fs.FileUtil;
 import org.apache.hadoop.thirdparty.com.google.common.base.Joiner;
 import org.apache.hadoop.thirdparty.com.google.common.collect.ImmutableList;
 import org.apache.hadoop.thirdparty.com.google.common.collect.LinkedListMultimap;
@@ -2066,4 +2069,56 @@ public class TestBlockManager {
     // validateReconstructionWork return false, need to perform resetTargets().
     assertNull(work.getTargets());
   }
+
+  /**
+   * Test whether the first block report after DataNode restart is completely
+   * processed.
+   */
+  @Test
+  public void testBlockReportAfterDataNodeRestart() throws Exception {
+    Configuration conf = new HdfsConfiguration();
+    try (MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
+           .numDataNodes(3).storagesPerDatanode(1).build()) {
+      cluster.waitActive();
+      BlockManager blockManager = cluster.getNamesystem().getBlockManager();
+      DistributedFileSystem fs = cluster.getFileSystem();
+      final Path filePath = new Path("/tmp.txt");
+      final long fileLen = 1L;
+      DFSTestUtil.createFile(fs, filePath, fileLen, (short) 3, 1L);
+      DFSTestUtil.waitForReplication(fs, filePath, (short) 3, 60000);
+      ArrayList<DataNode> datanodes = cluster.getDataNodes();
+      assertEquals(datanodes.size(), 3);
+
+      // Stop RedundancyMonitor.
+      blockManager.setInitializedReplQueues(false);
+
+      // Delete the replica on the first datanode.
+      DataNode dn = datanodes.get(0);
+      int dnIpcPort = dn.getIpcPort();
+      File dnDir = dn.getFSDataset().getVolumeList().get(0).getCurrentDir();
+      String[] children = FileUtil.list(dnDir);
+      for (String s : children) {
+        if (!s.equals("VERSION")) {
+          FileUtil.fullyDeleteContents(new File(dnDir, s));
+        }
+      }
+
+      // The number of replicas is still 3 because the datanode has not sent
+      // a new block report.
+      FileStatus stat = fs.getFileStatus(filePath);
+      BlockLocation[] locs = fs.getFileBlockLocations(stat, 0, stat.getLen());
+      assertEquals(3, locs[0].getHosts().length);
+
+      // Restart the first datanode.
+      cluster.restartDataNode(0, true);
+
+      // Wait for the block report to be processed.
+      cluster.waitDatanodeFullyStarted(cluster.getDataNode(dnIpcPort), 10000);
+      cluster.waitFirstBRCompleted(0, 10000);
+
+      // The replica num should be 2.
+      locs = fs.getFileBlockLocations(stat, 0, stat.getLen());
+      assertEquals(2, locs[0].getHosts().length);
+    }
+  }
 }