HDFS-10457. DataNode should not auto-format block pool directory if VERSION is missing. (Wei-Chiu Chuang via lei)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolSliceStorage.java

@@ -151,7 +151,7 @@ public class BlockPoolSliceStorage extends Storage {
           throws IOException {
     StorageDirectory sd = new StorageDirectory(dataDir, null, true);
     try {
-      StorageState curState = sd.analyzeStorage(startOpt, this);
+      StorageState curState = sd.analyzeStorage(startOpt, this, true);
       // sd is locked but not opened
       switch (curState) {
       case NORMAL:

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

@@ -43,6 +43,7 @@ import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager;
+import org.apache.hadoop.hdfs.server.common.Storage;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
 import org.apache.hadoop.hdfs.server.protocol.VolumeFailureSummary;
@@ -480,6 +481,25 @@ public class TestDataNodeVolumeFailureReporting {
     checkFailuresAtNameNode(dm, dns.get(0), false, dn1Vol1.getAbsolutePath());
   }
 
+  @Test
+  public void testAutoFormatEmptyBlockPoolDirectory() throws Exception {
+    // remove the version file
+    DataNode dn = cluster.getDataNodes().get(0);
+    String bpid = cluster.getNamesystem().getBlockPoolId();
+    BlockPoolSliceStorage bps = dn.getStorage().getBPStorage(bpid);
+    Storage.StorageDirectory dir = bps.getStorageDir(0);
+    File current = dir.getCurrentDir();
+
+    File currentVersion = new File(current, "VERSION");
+    currentVersion.delete();
+    // restart the data node
+    assertTrue(cluster.restartDataNodes(true));
+    // the DN should tolerate one volume failure.
+    cluster.waitActive();
+    assertFalse("DataNode should not reformat if VERSION is missing",
+        currentVersion.exists());
+  }
+
   /**
    * Checks the NameNode for correct values of aggregate counters tracking failed
    * volumes across all DataNodes.