HDFS-9498. Move code that tracks blocks with future generation stamps to BlockManagerSafeMode. (Contributed by Mingliang Liu)

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

@@ -1,4 +1,4 @@
- Hadoop HDFS Change Log
+Hadoop HDFS Change Log
 
 Trunk (Unreleased)
 
@@ -1800,6 +1800,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-7779. Support changing ownership, group and replication in HDFS Web
     UI. (Ravi Prakash via wheat9)
 
+    HDFS-9498. Move code that tracks blocks with future generation stamps
+    to BlockManagerSafeMode. (Mingliang Liu via Arpit Agarwal)
+
   OPTIMIZATIONS
 
     HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

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

@@ -73,7 +73,6 @@ import org.apache.hadoop.hdfs.security.token.block.ExportedBlockKeys;
 import org.apache.hadoop.hdfs.server.blockmanagement.CorruptReplicasMap.Reason;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeStorageInfo.AddBlockResult;
 import org.apache.hadoop.hdfs.server.blockmanagement.PendingDataNodeMessages.ReportedBlockInfo;
-import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.ReplicaState;
 import org.apache.hadoop.hdfs.server.namenode.CachedBlock;
@@ -309,12 +308,6 @@ public class BlockManager implements BlockStatsMXBean {
   /** Check whether there are any non-EC blocks using StripedID */
   private boolean hasNonEcBlockUsingStripedID = false;
 
-  /** Keeps track of how many bytes are in Future Generation blocks. */
-  private AtomicLong numberOfBytesInFutureBlocks;
-
-  /** Reports if Name node was started with Rollback option. */
-  private boolean inRollBack = false;
-
   public BlockManager(final Namesystem namesystem, final Configuration conf)
     throws IOException {
     this.namesystem = namesystem;
@@ -393,8 +386,6 @@ public class BlockManager implements BlockStatsMXBean {
         DFSConfigKeys.DFS_BLOCK_MISREPLICATION_PROCESSING_LIMIT,
         DFSConfigKeys.DFS_BLOCK_MISREPLICATION_PROCESSING_LIMIT_DEFAULT);
     this.blockReportLeaseManager = new BlockReportLeaseManager(conf);
-    this.numberOfBytesInFutureBlocks = new AtomicLong();
-    this.inRollBack = isInRollBackMode(NameNode.getStartupOption(conf));
 
     bmSafeMode = new BlockManagerSafeMode(this, namesystem, conf);
 
@@ -1964,14 +1955,18 @@ public class BlockManager implements BlockStatsMXBean {
     return bmSafeMode.getSafeModeTip();
   }
 
-  public void leaveSafeMode(boolean force) {
-    bmSafeMode.leaveSafeMode(force);
+  public boolean leaveSafeMode(boolean force) {
+    return bmSafeMode.leaveSafeMode(force);
   }
 
   void checkSafeMode() {
     bmSafeMode.checkSafeMode();
   }
 
+  public long getBytesInFuture() {
+    return bmSafeMode.getBytesInFuture();
+  }
+
   /**
    * Removes the blocks from blocksmap and updates the safemode blocks total.
    * @param blocks An instance of {@link BlocksMapUpdateInfo} which contains a
@@ -2370,12 +2365,7 @@ public class BlockManager implements BlockStatsMXBean {
       // If block does not belong to any file, we check if it violates
       // an integrity assumption of Name node
       if (storedBlock == null) {
-        if (namesystem.isInStartupSafeMode()
-            && !shouldPostponeBlocksFromFuture
-            && !inRollBack
-            && namesystem.isGenStampInFuture(iblk)) {
-          numberOfBytesInFutureBlocks.addAndGet(iblk.getBytesOnDisk());
-        }
+        bmSafeMode.checkBlocksWithFutureGS(iblk);
         continue;
       }
 
@@ -4254,39 +4244,8 @@ public class BlockManager implements BlockStatsMXBean {
     return haContext.getState().shouldPopulateReplQueues();
   }
 
-  /**
-   * Returns the number of bytes that reside in blocks with Generation Stamps
-   * greater than generation stamp known to Namenode.
-   *
-   * @return Bytes in future
-   */
-  public long getBytesInFuture() {
-    return numberOfBytesInFutureBlocks.get();
-  }
-
-  /**
-   * Clears the bytes in future counter.
-   */
-  public void clearBytesInFuture() {
-    numberOfBytesInFutureBlocks.set(0);
-  }
-
-  /**
-   * Returns true if Namenode was started with a RollBack option.
-   *
-   * @param option - StartupOption
-   * @return boolean
-   */
-  private boolean isInRollBackMode(HdfsServerConstants.StartupOption option) {
-    if (option == HdfsServerConstants.StartupOption.ROLLBACK) {
-      return true;
-    }
-    if ((option == HdfsServerConstants.StartupOption.ROLLINGUPGRADE) &&
-        (option.getRollingUpgradeStartupOption() ==
-            HdfsServerConstants.RollingUpgradeStartupOption.ROLLBACK)) {
-      return true;
-    }
-    return false;
+  boolean getShouldPostponeBlocksFromFuture() {
+    return shouldPostponeBlocksFromFuture;
   }
 
   // async processing of an action, used for IBRs.

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

@@ -21,6 +21,9 @@ import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.protocol.BlockListAsLongs.BlockReportReplica;
+import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.RollingUpgradeStartupOption;
+import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.StartupOption;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.Namesystem;
 import org.apache.hadoop.hdfs.server.namenode.startupprogress.Phase;
@@ -106,6 +109,11 @@ class BlockManagerSafeMode {
   /** Counter for tracking startup progress of reported blocks. */
   private Counter awaitingReportedBlocksCounter;
 
+  /** Keeps track of how many bytes are in Future Generation blocks. */
+  private final AtomicLong numberOfBytesInFutureBlocks = new AtomicLong();
+  /** Reports if Name node was started with Rollback option. */
+  private final boolean inRollBack;
+
   BlockManagerSafeMode(BlockManager blockManager, Namesystem namesystem,
       Configuration conf) {
     this.blockManager = blockManager;
@@ -135,9 +143,10 @@ class BlockManagerSafeMode {
     this.replQueueThreshold =
         conf.getFloat(DFS_NAMENODE_REPL_QUEUE_THRESHOLD_PCT_KEY,
             (float) threshold);
-
     this.extension = conf.getInt(DFS_NAMENODE_SAFEMODE_EXTENSION_KEY, 0);
 
+    this.inRollBack = isInRollBackMode(NameNode.getStartupOption(conf));
+
     LOG.info("{} = {}", DFS_NAMENODE_SAFEMODE_THRESHOLD_PCT_KEY, threshold);
     LOG.info("{} = {}", DFS_NAMENODE_SAFEMODE_MIN_DATANODES_KEY,
         datanodeThreshold);
@@ -300,15 +309,15 @@ class BlockManagerSafeMode {
           numLive, datanodeThreshold);
     }
 
-    if (blockManager.getBytesInFuture() > 0) {
+    if (getBytesInFuture() > 0) {
       msg += "Name node detected blocks with generation stamps " +
-          "in future. This means that Name node metadata is inconsistent." +
+          "in future. This means that Name node metadata is inconsistent. " +
           "This can happen if Name node metadata files have been manually " +
-          "replaced. Exiting safe mode will cause loss of " + blockManager
-          .getBytesInFuture() + " byte(s). Please restart name node with " +
-          "right metadata or use \"hdfs dfsadmin -safemode forceExit" +
-          "if you are certain that the NameNode was started with the" +
-          "correct FsImage and edit logs. If you encountered this during" +
+          "replaced. Exiting safe mode will cause loss of " +
+          getBytesInFuture() + " byte(s). Please restart name node with " +
+          "right metadata or use \"hdfs dfsadmin -safemode forceExit\" " +
+          "if you are certain that the NameNode was started with the " +
+          "correct FsImage and edit logs. If you encountered this during " +
           "a rollback, it is safe to exit with -safemode forceExit.";
       return msg;
     }
@@ -333,11 +342,31 @@ class BlockManagerSafeMode {
 
   /**
    * Leave start up safe mode.
+   *
    * @param force - true to force exit
+   * @return true if it leaves safe mode successfully else false
    */
-  void leaveSafeMode(boolean force) {
+  boolean leaveSafeMode(boolean force) {
     assert namesystem.hasWriteLock() : "Leaving safe mode needs write lock!";
 
+    final long bytesInFuture = numberOfBytesInFutureBlocks.get();
+    if (bytesInFuture > 0) {
+      if (force) {
+        LOG.warn("Leaving safe mode due to forceExit. This will cause a data "
+            + "loss of {} byte(s).", bytesInFuture);
+        numberOfBytesInFutureBlocks.set(0);
+      } else {
+        LOG.error("Refusing to leave safe mode without a force flag. " +
+            "Exiting safe mode will cause a deletion of {} byte(s). Please " +
+            "use -forceExit flag to exit safe mode forcefully if data loss is" +
+            " acceptable.", bytesInFuture);
+        return false;
+      }
+    } else if (force) {
+      LOG.warn("forceExit used when normal exist would suffice. Treating " +
+          "force exit as normal safe mode exit.");
+    }
+
     // if not done yet, initialize replication queues.
     // In the standby, do not populate repl queues
     if (!blockManager.isPopulatingReplQueues() &&
@@ -345,14 +374,6 @@ class BlockManagerSafeMode {
       blockManager.initializeReplQueues();
     }
 
-    if (!force && blockManager.getBytesInFuture() > 0) {
-      LOG.error("Refusing to leave safe mode without a force flag. " +
-          "Exiting safe mode will cause a deletion of {} byte(s). Please use " +
-          "-forceExit flag to exit safe mode forcefully if data loss is " +
-          "acceptable.", blockManager.getBytesInFuture());
-      return;
-    }
-
     if (status != BMSafeModeStatus.OFF) {
       NameNode.stateChangeLog.info("STATE* Safe mode is OFF");
     }
@@ -379,6 +400,8 @@ class BlockManagerSafeMode {
           BlockManagerSafeMode.STEP_AWAITING_REPORTED_BLOCKS);
       prog.endPhase(Phase.SAFEMODE);
     }
+
+    return true;
   }
 
   /**
@@ -436,6 +459,35 @@ class BlockManagerSafeMode {
     }
   }
 
+  /**
+   * Check if the block report replica has a generation stamp (GS) in future.
+   * If safe mode is not currently on, this is a no-op.
+   *
+   * @param brr block report replica which belongs to no file in BlockManager
+   */
+  void checkBlocksWithFutureGS(BlockReportReplica brr) {
+    assert namesystem.hasWriteLock();
+    if (status == BMSafeModeStatus.OFF) {
+      return;
+    }
+
+    if (!blockManager.getShouldPostponeBlocksFromFuture() &&
+        !inRollBack &&
+        namesystem.isGenStampInFuture(brr)) {
+      numberOfBytesInFutureBlocks.addAndGet(brr.getBytesOnDisk());
+    }
+  }
+
+  /**
+   * Returns the number of bytes that reside in blocks with Generation Stamps
+   * greater than generation stamp known to Namenode.
+   *
+   * @return Bytes in future
+   */
+  long getBytesInFuture() {
+    return numberOfBytesInFutureBlocks.get();
+  }
+
   void close() {
     assert namesystem.hasWriteLock() : "Closing bmSafeMode needs write lock!";
     try {
@@ -454,6 +506,19 @@ class BlockManagerSafeMode {
     return reachedTime.get() + extension - monotonicNow();
   }
 
+  /**
+   * Returns true if Namenode was started with a RollBack option.
+   *
+   * @param option - StartupOption
+   * @return boolean
+   */
+  private static boolean isInRollBackMode(StartupOption option) {
+    return (option == StartupOption.ROLLBACK) ||
+        (option == StartupOption.ROLLINGUPGRADE &&
+            option.getRollingUpgradeStartupOption() ==
+                RollingUpgradeStartupOption.ROLLBACK);
+  }
+
   /** Check if we are ready to initialize replication queues. */
   private void initializeReplQueuesIfNecessary() {
     assert namesystem.hasWriteLock();

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -986,6 +986,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
   
   @Override
   public void startSecretManagerIfNecessary() {
+    assert hasWriteLock() : "Starting secret manager needs write lock";
     boolean shouldRun = shouldUseDelegationTokens() &&
       !isInSafeMode() && getEditLog().isOpenForWrite();
     boolean running = dtSecretManager.isRunning();
@@ -4006,29 +4007,13 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
       checkSuperuserPrivilege();
       switch(action) {
       case SAFEMODE_LEAVE: // leave safe mode
-        if (blockManager.getBytesInFuture() > 0) {
-          LOG.error("Refusing to leave safe mode without a force flag. " +
-              "Exiting safe mode will cause a deletion of " + blockManager
-              .getBytesInFuture() + " byte(s). Please use " +
-              "-forceExit flag to exit safe mode forcefully and data loss is " +
-              "acceptable.");
-        } else {
-          leaveSafeMode();
-        }
+        leaveSafeMode(false);
         break;
       case SAFEMODE_ENTER: // enter safe mode
         enterSafeMode(false);
         break;
       case SAFEMODE_FORCE_EXIT:
-        if (blockManager.getBytesInFuture() > 0) {
-          LOG.warn("Leaving safe mode due to forceExit. This will cause a data "
-              + "loss of " + blockManager.getBytesInFuture() + " byte(s).");
-          blockManager.clearBytesInFuture();
-        } else {
-          LOG.warn("forceExit used when normal exist would suffice. Treating " +
-              "force exit as normal safe mode exit.");
-        }
-        leaveSafeMode();
+        leaveSafeMode(true);
         break;
       default:
         LOG.error("Unexpected safe mode action");
@@ -4125,16 +4110,19 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
 
   /**
    * Leave safe mode.
+   * @param force true if to leave safe mode forcefully with -forceExit option
    */
-  void leaveSafeMode() {
+  void leaveSafeMode(boolean force) {
     writeLock();
     try {
       if (!isInSafeMode()) {
         NameNode.stateChangeLog.info("STATE* Safe mode is already OFF"); 
         return;
       }
-      setManualAndResourceLowSafeMode(false, false);
-      blockManager.leaveSafeMode(true);
+      if (blockManager.leaveSafeMode(force)) {
+        setManualAndResourceLowSafeMode(false, false);
+        startSecretManagerIfNecessary();
+      }
     } finally {
       writeUnlock();
     }

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

@@ -22,6 +22,7 @@ import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.protocol.Block;
+import org.apache.hadoop.hdfs.protocol.BlockListAsLongs.BlockReportReplica;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManagerSafeMode.BMSafeModeStatus;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.NamenodeRole;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
@@ -31,7 +32,6 @@ import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.Before;
 import org.junit.Test;
 
-import org.mockito.Mockito;
 import org.mockito.internal.util.reflection.Whitebox;
 
 import java.io.IOException;
@@ -42,7 +42,6 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
-import static org.junit.Assert.fail;
 import static org.mockito.Matchers.any;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
@@ -92,9 +91,10 @@ public class TestBlockManagerSafeMode {
         DATANODE_NUM);
 
     FSNamesystem fsn = mock(FSNamesystem.class);
-    Mockito.doReturn(true).when(fsn).hasWriteLock();
-    Mockito.doReturn(true).when(fsn).hasReadLock();
-    Mockito.doReturn(true).when(fsn).isRunning();
+    doReturn(true).when(fsn).hasWriteLock();
+    doReturn(true).when(fsn).hasReadLock();
+    doReturn(true).when(fsn).isRunning();
+    doReturn(true).when(fsn).isGenStampInFuture(any(Block.class));
     NameNode.initMetrics(conf, NamenodeRole.NAMENODE);
 
     bm = spy(new BlockManager(fsn, conf));
@@ -110,7 +110,7 @@ public class TestBlockManagerSafeMode {
    * Test set block total.
    *
    * The block total is set which will call checkSafeMode for the first time
-   * and bmSafeMode transfers from INITIALIZED to PENDING_THRESHOLD status
+   * and bmSafeMode transfers from OFF to PENDING_THRESHOLD status
    */
   @Test(timeout = 30000)
   public void testInitialize() {
@@ -170,7 +170,7 @@ public class TestBlockManagerSafeMode {
    *
    * Once the block threshold is reached, the block manger leaves safe mode and
    * increment will be a no-op.
-   * The safe mode status lifecycle: INITIALIZED -> PENDING_THRESHOLD -> OFF
+   * The safe mode status lifecycle: OFF -> PENDING_THRESHOLD -> OFF
    */
   @Test(timeout = 30000)
   public void testIncrementSafeBlockCount() {
@@ -198,7 +198,7 @@ public class TestBlockManagerSafeMode {
    *
    * Once the block threshold is reached, the block manger leaves safe mode and
    * increment will be a no-op.
-   * The safe mode status lifecycle: INITIALIZED -> PENDING_THRESHOLD -> EXTENSION-> OFF
+   * The safe mode status lifecycle: OFF -> PENDING_THRESHOLD -> EXTENSION-> OFF
    */
   @Test(timeout = 30000)
   public void testIncrementSafeBlockCountWithExtension() throws Exception {
@@ -220,7 +220,7 @@ public class TestBlockManagerSafeMode {
    * Test that the block safe decreases the block safe.
    *
    * The block manager stays in safe mode.
-   * The safe mode status lifecycle: INITIALIZED -> PENDING_THRESHOLD
+   * The safe mode status lifecycle: OFF -> PENDING_THRESHOLD
    */
   @Test(timeout = 30000)
   public void testDecrementSafeBlockCount() {
@@ -242,7 +242,7 @@ public class TestBlockManagerSafeMode {
    * Test when the block safe increment and decrement interleave.
    *
    * Both the increment and decrement will be a no-op if the safe mode is OFF.
-   * The safe mode status lifecycle: INITIALIZED -> PENDING_THRESHOLD -> OFF
+   * The safe mode status lifecycle: OFF -> PENDING_THRESHOLD -> OFF
    */
   @Test(timeout = 30000)
   public void testIncrementAndDecrementSafeBlockCount() {
@@ -309,24 +309,31 @@ public class TestBlockManagerSafeMode {
   }
 
   /**
-   * Test block manager won't leave safe mode if there are orphan blocks.
+   * Test block manager won't leave safe mode if there are blocks with
+   * generation stamp (GS) in future.
    */
   @Test(timeout = 30000)
   public void testStayInSafeModeWhenBytesInFuture() throws Exception {
     bmSafeMode.activate(BLOCK_TOTAL);
 
-    when(bm.getBytesInFuture()).thenReturn(1L);
+    // Inject blocks with future GS
+    injectBlocksWithFugureGS(100L);
+    assertEquals(100L, bmSafeMode.getBytesInFuture());
+
     // safe blocks are enough
    setBlockSafe(BLOCK_THRESHOLD);
 
     // PENDING_THRESHOLD -> EXTENSION
     bmSafeMode.checkSafeMode();
-    try {
-      waitForExtensionPeriod();
-      fail("Safe mode should not leave extension period with orphan blocks!");
-    } catch (TimeoutException e) {
-      assertEquals(BMSafeModeStatus.EXTENSION, getSafeModeStatus());
-    }
+
+    assertFalse("Shouldn't leave safe mode in case of blocks with future GS! ",
+        bmSafeMode.leaveSafeMode(false));
+    assertTrue("Leaving safe mode forcefully should succeed regardless of " +
+        "blocks with future GS.", bmSafeMode.leaveSafeMode(true));
+    assertEquals("Number of blocks with future GS should have been cleared " +
+        "after leaving safe mode", 0L, bmSafeMode.getBytesInFuture());
+    assertTrue("Leaving safe mode should succeed after blocks with future GS " +
+        "are cleared.", bmSafeMode.leaveSafeMode(false));
   }
 
   /**
@@ -353,7 +360,7 @@ public class TestBlockManagerSafeMode {
     tip = bmSafeMode.getSafeModeTip();
     assertTrue(tip.contains(
         String.format("The reported blocks %d has reached the threshold"
-            + " %.4f of total blocks %d. ",
+                + " %.4f of total blocks %d. ",
             getblockSafe(), THRESHOLD, BLOCK_TOTAL)));
     assertTrue(tip.contains(
         String.format("The number of live datanodes %d has reached the " +
@@ -363,7 +370,6 @@ public class TestBlockManagerSafeMode {
 
     waitForExtensionPeriod();
     tip = bmSafeMode.getSafeModeTip();
-    System.out.println(tip);
     assertTrue(tip.contains(
         String.format("The reported blocks %d has reached the threshold"
                 + " %.4f of total blocks %d. ",
@@ -375,7 +381,55 @@ public class TestBlockManagerSafeMode {
   }
 
   /**
-   * Mock block manager internal state for decrement safe block
+   * Test get safe mode tip in case of blocks with future GS.
+   */
+  @Test(timeout = 30000)
+  public void testGetSafeModeTipForBlocksWithFutureGS() throws Exception {
+    bmSafeMode.activate(BLOCK_TOTAL);
+
+    injectBlocksWithFugureGS(40L);
+    String tip = bmSafeMode.getSafeModeTip();
+    assertTrue(tip.contains(
+        String.format(
+            "The reported blocks %d needs additional %d blocks to reach the " +
+                "threshold %.4f of total blocks %d.%n",
+            0, BLOCK_THRESHOLD, THRESHOLD, BLOCK_TOTAL)));
+    assertTrue(tip.contains(
+        "Name node detected blocks with generation stamps " +
+            "in future. This means that Name node metadata is inconsistent. " +
+            "This can happen if Name node metadata files have been manually " +
+            "replaced. Exiting safe mode will cause loss of " +
+            40 + " byte(s). Please restart name node with " +
+            "right metadata or use \"hdfs dfsadmin -safemode forceExit\" " +
+            "if you are certain that the NameNode was started with the " +
+            "correct FsImage and edit logs. If you encountered this during " +
+            "a rollback, it is safe to exit with -safemode forceExit."
+    ));
+    assertFalse(tip.contains("Safe mode will be turned off"));
+
+    // blocks with future GS were already injected before.
+    setBlockSafe(BLOCK_THRESHOLD);
+    tip = bmSafeMode.getSafeModeTip();
+    assertTrue(tip.contains(
+        String.format("The reported blocks %d has reached the threshold"
+                + " %.4f of total blocks %d. ",
+            getblockSafe(), THRESHOLD, BLOCK_TOTAL)));
+    assertTrue(tip.contains(
+        "Name node detected blocks with generation stamps " +
+            "in future. This means that Name node metadata is inconsistent. " +
+            "This can happen if Name node metadata files have been manually " +
+            "replaced. Exiting safe mode will cause loss of " +
+            40 + " byte(s). Please restart name node with " +
+            "right metadata or use \"hdfs dfsadmin -safemode forceExit\" " +
+            "if you are certain that the NameNode was started with the " +
+            "correct FsImage and edit logs. If you encountered this during " +
+            "a rollback, it is safe to exit with -safemode forceExit."
+    ));
+    assertFalse(tip.contains("Safe mode will be turned off"));
+  }
+
+  /**
+   * Mock block manager internal state for decrement safe block.
    */
   private void mockBlockManagerForBlockSafeDecrement() {
     BlockInfo storedBlock = mock(BlockInfo.class);
@@ -402,6 +456,12 @@ public class TestBlockManagerSafeMode {
     }, EXTENSION / 10, EXTENSION * 2);
   }
 
+  private void injectBlocksWithFugureGS(long numBytesInFuture) {
+    BlockReportReplica brr = mock(BlockReportReplica.class);
+    when(brr.getBytesOnDisk()).thenReturn(numBytesInFuture);
+    bmSafeMode.checkBlocksWithFutureGS(brr);
+  }
+
   private void setSafeModeStatus(BMSafeModeStatus status) {
     Whitebox.setInternalState(bmSafeMode, "status", status);
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/NameNodeAdapter.java

@@ -96,7 +96,7 @@ public class NameNodeAdapter {
   }
   
   public static void leaveSafeMode(NameNode namenode) {
-    namenode.getNamesystem().leaveSafeMode();
+    namenode.getNamesystem().leaveSafeMode(false);
   }
   
   public static void abortEditLogs(NameNode nn) {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestCheckpoint.java

@@ -1608,7 +1608,7 @@ public class TestCheckpoint {
       FSNamesystem fsns = cluster.getNamesystem();
       fsns.enterSafeMode(false);
       fsns.saveNamespace(0, 0);
-      fsns.leaveSafeMode();
+      fsns.leaveSafeMode(false);
       
       secondary = startSecondaryNameNode(conf);
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestEditLogRace.java

@@ -306,7 +306,7 @@ public class TestEditLogRace {
         assertEquals(fsimage.getStorage().getMostRecentCheckpointTxId(),
                      editLog.getLastWrittenTxId() - 1);
 
-        namesystem.leaveSafeMode();
+        namesystem.leaveSafeMode(false);
         LOG.info("Save " + i + ": complete");
       }
     } finally {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFSEditLogLoader.java

@@ -464,7 +464,7 @@ public class TestFSEditLogLoader {
 
       fns.enterSafeMode(false);
       fns.saveNamespace(0, 0);
-      fns.leaveSafeMode();
+      fns.leaveSafeMode(false);
 
       // Add a striped block to the file
       BlockInfoStriped stripedBlk = new BlockInfoStriped(
@@ -542,7 +542,7 @@ public class TestFSEditLogLoader {
       file.toCompleteFile(System.currentTimeMillis());
       fns.enterSafeMode(false);
       fns.saveNamespace(0, 0);
-      fns.leaveSafeMode();
+      fns.leaveSafeMode(false);
 
       //update the last block
       long newBlkNumBytes = 1024*8;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFSNamesystem.java

@@ -105,7 +105,7 @@ public class TestFSNamesystem {
     Mockito.when(fsImage.getEditLog()).thenReturn(fsEditLog);
     FSNamesystem fsn = new FSNamesystem(conf, fsImage);
 
-    fsn.leaveSafeMode();
+    fsn.leaveSafeMode(false);
     assertTrue("After leaving safemode FSNamesystem.isInStartupSafeMode still "
       + "returned true", !fsn.isInStartupSafeMode());
     assertTrue("After leaving safemode FSNamesystem.isInSafeMode still returned"
@@ -145,7 +145,7 @@ public class TestFSNamesystem {
     assertTrue("FSNamesystem didn't enter safemode", fsn.isInSafeMode());
     assertTrue("Replication queues were being populated during very first "
         + "safemode", !bm.isPopulatingReplQueues());
-    fsn.leaveSafeMode();
+    fsn.leaveSafeMode(false);
     assertTrue("FSNamesystem didn't leave safemode", !fsn.isInSafeMode());
     assertTrue("Replication queues weren't being populated even after leaving "
       + "safemode", bm.isPopulatingReplQueues());

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestINodeFile.java

@@ -490,7 +490,7 @@ public class TestINodeFile {
       // Apply editlogs to fsimage, ensure inodeUnderConstruction is handled
       fsn.enterSafeMode(false);
       fsn.saveNamespace(0, 0);
-      fsn.leaveSafeMode();
+      fsn.leaveSafeMode(false);
 
       outStream.close();
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestNameNodeMetadataConsistency.java

@@ -23,26 +23,26 @@ import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.hdfs.MiniDFSCluster.DataNodeProperties;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
-import org.hamcrest.CoreMatchers;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockManagerTestUtil;
+
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-import org.mockito.Mockito;
-import org.mockito.internal.util.reflection.Whitebox;
 
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.concurrent.TimeUnit;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
-import static org.mockito.Mockito.*;
+import static org.junit.Assert.assertTrue;
 
 public class TestNameNodeMetadataConsistency {
   private static final Path filePath1 = new Path("/testdata1.txt");
   private static final Path filePath2 = new Path("/testdata2.txt");
+  private static final String TEST_DATA_IN_FUTURE = "This is test data";
 
   private static final int SCAN_INTERVAL = 1;
   private static final int SCAN_WAIT = 3;
@@ -75,59 +75,45 @@ public class TestNameNodeMetadataConsistency {
   @Test
   public void testGenerationStampInFuture() throws
       IOException, InterruptedException {
-
-    String testData = " This is test data";
-    int datalen = testData.length();
-
     cluster.waitActive();
+
     FileSystem fs = cluster.getFileSystem();
     OutputStream ostream = fs.create(filePath1);
-    ostream.write(testData.getBytes());
+    ostream.write(TEST_DATA_IN_FUTURE.getBytes());
     ostream.close();
 
-    ExtendedBlock block = DFSTestUtil.getFirstBlock(fs, filePath1);
-    long genStamp = block.getGenerationStamp();
-
     // Re-write the Generation Stamp to a Generation Stamp in future.
-    cluster.changeGenStampOfBlock(0, block, genStamp + 1);
-    MiniDFSCluster.DataNodeProperties dnProps = cluster.stopDataNode(0);
-
+    ExtendedBlock block = DFSTestUtil.getFirstBlock(fs, filePath1);
+    final long genStamp = block.getGenerationStamp();
+    final int datanodeIndex = 0;
+    cluster.changeGenStampOfBlock(datanodeIndex, block, genStamp + 1);
+    // stop the data node so that it won't remove block
+    final DataNodeProperties dnProps = cluster.stopDataNode(datanodeIndex);
 
-    // Simulate  Namenode forgetting a Block
+    // Simulate Namenode forgetting a Block
     cluster.restartNameNode(true);
-    BlockInfo bInfo = cluster.getNameNode().getNamesystem().getBlockManager
-        ().getStoredBlock(block.getLocalBlock());
     cluster.getNameNode().getNamesystem().writeLock();
+    BlockInfo bInfo = cluster.getNameNode().getNamesystem().getBlockManager()
+        .getStoredBlock(block.getLocalBlock());
     cluster.getNameNode().getNamesystem().getBlockManager()
         .removeBlock(bInfo);
     cluster.getNameNode().getNamesystem().writeUnlock();
 
     // we also need to tell block manager that we are in the startup path
-    FSNamesystem spyNameSystem = spy(cluster.getNameNode().getNamesystem());
-    Whitebox.setInternalState(cluster.getNameNode()
-            .getNamesystem().getBlockManager(),
-        "namesystem", spyNameSystem);
-    Whitebox.setInternalState(cluster.getNameNode(),
-        "namesystem", spyNameSystem);
-    Mockito.doReturn(true).when(spyNameSystem).isInStartupSafeMode();
-
+    BlockManagerTestUtil.setStartupSafeModeForTest(
+        cluster.getNameNode().getNamesystem().getBlockManager());
 
-    // Since Data Node is already shutdown we didn't remove blocks
     cluster.restartDataNode(dnProps);
     waitTil(TimeUnit.SECONDS.toMillis(SCAN_WAIT));
     cluster.triggerBlockReports();
-
-    // Give some buffer to process the block reports
     waitTil(TimeUnit.SECONDS.toMillis(SCAN_WAIT));
 
     // Make sure that we find all written bytes in future block
-    assertEquals(datalen, cluster.getNameNode().getBytesWithFutureGenerationStamps());
-
+    assertEquals(TEST_DATA_IN_FUTURE.length(),
+        cluster.getNameNode().getBytesWithFutureGenerationStamps());
     // Assert safemode reason
-    String safeModeMessage = cluster.getNameNode().getNamesystem()
-        .getSafeModeTip();
-    assertThat(safeModeMessage, CoreMatchers.containsString("Name node " +
-        "detected blocks with generation stamps in future"));
+    assertTrue(cluster.getNameNode().getNamesystem().getSafeModeTip().contains(
+        "Name node detected blocks with generation stamps in future"));
   }
 
   /**