HDFS-11659. TestDataNodeHotSwapVolumes.testRemoveVolumeBeingWritten fail due to no DataNode available for pipeline recovery. Contributed by Lei (Eddy) Xu.

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeHotSwapVolumes.java

@@ -894,6 +894,9 @@ public class TestDataNodeHotSwapVolumes {
           1, fsVolumeReferences.size());
     }
 
+    // Add a new DataNode to help with the pipeline recover.
+    cluster.startDataNodes(conf, 1, true, null, null, null);
+
     // Verify the file has sufficient replications.
     DFSTestUtil.waitReplication(fs, testFile, REPLICATION);
     // Read the content back
@@ -925,6 +928,32 @@ public class TestDataNodeHotSwapVolumes {
       assertTrue(String.format("DataNode(%d) should have more than 1 blocks",
           dataNodeIdx), blockCount > 1);
     }
+
+    // Write more files to make sure that the DataNode that has removed volume
+    // is still alive to receive data.
+    for (int i = 0; i < 10; i++) {
+      final Path file = new Path("/after-" + i);
+      try (FSDataOutputStream fout = fs.create(file, REPLICATION)) {
+        rb.nextBytes(writeBuf);
+        fout.write(writeBuf);
+      }
+    }
+
+    try (FsDatasetSpi.FsVolumeReferences fsVolumeReferences = fsDatasetSpi
+        .getFsVolumeReferences()) {
+      assertEquals("Volume remove wasn't successful.",
+          1, fsVolumeReferences.size());
+      FsVolumeSpi volume = fsVolumeReferences.get(0);
+      String bpid = cluster.getNamesystem().getBlockPoolId();
+      FsVolumeSpi.BlockIterator blkIter = volume.newBlockIterator(bpid, "test");
+      int blockCount = 0;
+      while (!blkIter.atEnd()) {
+        blkIter.nextBlock();
+        blockCount++;
+      }
+      assertTrue(String.format("DataNode(%d) should have more than 1 blocks",
+          dataNodeIdx), blockCount > 1);
+    }
   }
 
   @Test(timeout=60000)