HDFS-3970. Fix bug causing rollback of HDFS upgrade to result in bad VERSION file. Contributed by Vinay and Andrew Wang.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1430038 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -357,6 +357,9 @@ Release 2.0.3-alpha - Unreleased
     HDFS-4302. Fix fatal exception when starting NameNode with DEBUG logs
     (Eugene Koontz via todd)
 
+    HDFS-3970. Fix bug causing rollback of HDFS upgrade to result in bad
+    VERSION file. (Vinay and Andrew Wang via atm)
+
   BREAKDOWN OF HDFS-3077 SUBTASKS
 
     HDFS-3077. Quorum-based protocol for reading and writing edit logs.

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

@@ -78,6 +78,10 @@ public class BlockPoolSliceStorage extends Storage {
     this.clusterID = clusterId;
   }
 
+  private BlockPoolSliceStorage() {
+    super(NodeType.DATA_NODE);
+  }
+
   /**
    * Analyze storage directories. Recover from previous transitions if required.
    * 
@@ -378,7 +382,7 @@ public class BlockPoolSliceStorage extends Storage {
     if (!prevDir.exists())
       return;
     // read attributes out of the VERSION file of previous directory
-    DataStorage prevInfo = new DataStorage();
+    BlockPoolSliceStorage prevInfo = new BlockPoolSliceStorage();
     prevInfo.readPreviousVersionProperties(bpSd);
 
     // We allow rollback to a state, which is either consistent with

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSRollback.java

@@ -19,6 +19,7 @@ package org.apache.hadoop.hdfs;
 
 import static org.apache.hadoop.hdfs.server.common.HdfsServerConstants.NodeType.DATA_NODE;
 import static org.apache.hadoop.hdfs.server.common.HdfsServerConstants.NodeType.NAME_NODE;
+import static org.junit.Assert.*;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.fail;
@@ -31,6 +32,7 @@ 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.Path;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.NodeType;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.StartupOption;
 import org.apache.hadoop.hdfs.server.common.StorageInfo;
@@ -176,6 +178,44 @@ public class TestDFSRollback {
       cluster.shutdown();
       UpgradeUtilities.createEmptyDirs(nameNodeDirs);
       UpgradeUtilities.createEmptyDirs(dataNodeDirs);
+      
+      log("Normal BlockPool rollback", numDirs);
+      UpgradeUtilities.createNameNodeStorageDirs(nameNodeDirs, "current");
+      UpgradeUtilities.createNameNodeStorageDirs(nameNodeDirs, "previous");
+      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0)
+                                                .format(false)
+                                                .manageDataDfsDirs(false)
+                                                .manageNameDfsDirs(false)
+                                                .startupOption(StartupOption.ROLLBACK)
+                                                .build();
+      UpgradeUtilities.createDataNodeStorageDirs(dataNodeDirs, "current");
+      UpgradeUtilities.createBlockPoolStorageDirs(dataNodeDirs, "current",
+          UpgradeUtilities.getCurrentBlockPoolID(cluster));
+      // Create a previous snapshot for the blockpool
+      UpgradeUtilities.createBlockPoolStorageDirs(dataNodeDirs, "previous",
+          UpgradeUtilities.getCurrentBlockPoolID(cluster));
+      // Older LayoutVersion to make it rollback
+      storageInfo = new StorageInfo(
+          UpgradeUtilities.getCurrentLayoutVersion()+1,
+          UpgradeUtilities.getCurrentNamespaceID(cluster),
+          UpgradeUtilities.getCurrentClusterID(cluster),
+          UpgradeUtilities.getCurrentFsscTime(cluster));
+      // Create old VERSION file for each data dir
+      for (int i=0; i<dataNodeDirs.length; i++) {
+        Path bpPrevPath = new Path(dataNodeDirs[i] + "/current/"
+            + UpgradeUtilities.getCurrentBlockPoolID(cluster));
+        UpgradeUtilities.createBlockPoolVersionFile(
+            new File(bpPrevPath.toString()),
+            storageInfo,
+            UpgradeUtilities.getCurrentBlockPoolID(cluster));
+      }
+
+      cluster.startDataNodes(conf, 1, false, StartupOption.ROLLBACK, null);
+      assertTrue(cluster.isDataNodeUp());
+
+      cluster.shutdown();
+      UpgradeUtilities.createEmptyDirs(nameNodeDirs);
+      UpgradeUtilities.createEmptyDirs(dataNodeDirs);
 
       log("NameNode rollback without existing previous dir", numDirs);
       UpgradeUtilities.createNameNodeStorageDirs(nameNodeDirs, "current");