HDFS-8493. Consolidate truncate() related implementation in a single class. Contributed by Rakesh R.

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

@@ -685,6 +685,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-8653. Code cleanup for DatanodeManager, DatanodeDescriptor and
     DatanodeStorageInfo. (Zhe Zhang via wang)
 
+    HDFS-8493. Consolidate truncate() related implementation in a single class.
+    (Rakesh R via wheat9)
+
   OPTIMIZATIONS
 
     HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

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

@@ -0,0 +1,361 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode;
+
+import java.io.IOException;
+
+import org.apache.hadoop.HadoopIllegalArgumentException;
+import org.apache.hadoop.fs.UnresolvedLinkException;
+import org.apache.hadoop.fs.permission.FsAction;
+import org.apache.hadoop.hdfs.protocol.Block;
+import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
+import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
+import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
+import org.apache.hadoop.hdfs.protocol.SnapshotAccessControlException;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstructionContiguous;
+import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
+import org.apache.hadoop.hdfs.server.namenode.FSNamesystem.RecoverLeaseOp;
+import org.apache.hadoop.hdfs.server.namenode.INode.BlocksMapUpdateInfo;
+
+import com.google.common.annotations.VisibleForTesting;
+
+/**
+ * Helper class to perform truncate operation.
+ */
+final class FSDirTruncateOp {
+
+  /**
+   * Private constructor for preventing FSDirTruncateOp object creation.
+   * Static-only class.
+   */
+  private FSDirTruncateOp() {}
+
+  /**
+   * Truncate a file to a given size.
+   *
+   * @param fsn namespace
+   * @param srcArg path name
+   * @param newLength the target file size
+   * @param clientName client name
+   * @param clientMachine client machine info
+   * @param mtime modified time
+   * @param toRemoveBlocks to be removed blocks
+   * @param pc permission checker to check fs permission
+   * @return tuncate result
+   * @throws IOException
+   */
+  static TruncateResult truncate(final FSNamesystem fsn, final String srcArg,
+      final long newLength, final String clientName,
+      final String clientMachine, final long mtime,
+      final BlocksMapUpdateInfo toRemoveBlocks, final FSPermissionChecker pc)
+      throws IOException, UnresolvedLinkException {
+    assert fsn.hasWriteLock();
+
+    FSDirectory fsd = fsn.getFSDirectory();
+    byte[][] pathComponents = FSDirectory
+        .getPathComponentsForReservedPath(srcArg);
+    final String src;
+    final INodesInPath iip;
+    final boolean onBlockBoundary;
+    Block truncateBlock = null;
+    fsd.writeLock();
+    try {
+      src = fsd.resolvePath(pc, srcArg, pathComponents);
+      iip = fsd.getINodesInPath4Write(src, true);
+      if (fsn.isPermissionEnabled()) {
+        fsd.checkPathAccess(pc, iip, FsAction.WRITE);
+      }
+      INodeFile file = INodeFile.valueOf(iip.getLastINode(), src);
+      final BlockStoragePolicy lpPolicy = fsn.getBlockManager()
+          .getStoragePolicy("LAZY_PERSIST");
+
+      if (lpPolicy != null && lpPolicy.getId() == file.getStoragePolicyID()) {
+        throw new UnsupportedOperationException(
+            "Cannot truncate lazy persist file " + src);
+      }
+
+      // Check if the file is already being truncated with the same length
+      final BlockInfo last = file.getLastBlock();
+      if (last != null && last.getBlockUCState()
+          == BlockUCState.UNDER_RECOVERY) {
+        final Block truncatedBlock = ((BlockInfoUnderConstruction) last)
+            .getTruncateBlock();
+        if (truncatedBlock != null) {
+          final long truncateLength = file.computeFileSize(false, false)
+              + truncatedBlock.getNumBytes();
+          if (newLength == truncateLength) {
+            return new TruncateResult(false, fsd.getAuditFileInfo(iip));
+          }
+        }
+      }
+
+      // Opening an existing file for truncate. May need lease recovery.
+      fsn.recoverLeaseInternal(RecoverLeaseOp.TRUNCATE_FILE, iip, src,
+          clientName, clientMachine, false);
+      // Truncate length check.
+      long oldLength = file.computeFileSize();
+      if (oldLength == newLength) {
+        return new TruncateResult(true, fsd.getAuditFileInfo(iip));
+      }
+      if (oldLength < newLength) {
+        throw new HadoopIllegalArgumentException(
+            "Cannot truncate to a larger file size. Current size: " + oldLength
+                + ", truncate size: " + newLength + ".");
+      }
+      // Perform INodeFile truncation.
+      final QuotaCounts delta = new QuotaCounts.Builder().build();
+      onBlockBoundary = unprotectedTruncate(fsn, iip, newLength,
+          toRemoveBlocks, mtime, delta);
+      if (!onBlockBoundary) {
+        // Open file for write, but don't log into edits
+        long lastBlockDelta = file.computeFileSize() - newLength;
+        assert lastBlockDelta > 0 : "delta is 0 only if on block bounday";
+        truncateBlock = prepareFileForTruncate(fsn, iip, clientName,
+            clientMachine, lastBlockDelta, null);
+      }
+
+      // update the quota: use the preferred block size for UC block
+      fsd.updateCountNoQuotaCheck(iip, iip.length() - 1, delta);
+    } finally {
+      fsd.writeUnlock();
+    }
+
+    fsn.getEditLog().logTruncate(src, clientName, clientMachine, newLength,
+        mtime, truncateBlock);
+    return new TruncateResult(onBlockBoundary, fsd.getAuditFileInfo(iip));
+  }
+
+  /**
+   * Unprotected truncate implementation. Unlike
+   * {@link FSDirTruncateOp#truncate}, this will not schedule block recovery.
+   *
+   * @param fsn namespace
+   * @param src path name
+   * @param clientName client name
+   * @param clientMachine client machine info
+   * @param newLength the target file size
+   * @param mtime modified time
+   * @param truncateBlock truncate block
+   * @throws IOException
+   */
+  static void unprotectedTruncate(final FSNamesystem fsn, final String src,
+      final String clientName, final String clientMachine,
+      final long newLength, final long mtime, final Block truncateBlock)
+      throws UnresolvedLinkException, QuotaExceededException,
+      SnapshotAccessControlException, IOException {
+    assert fsn.hasWriteLock();
+
+    FSDirectory fsd = fsn.getFSDirectory();
+    INodesInPath iip = fsd.getINodesInPath(src, true);
+    INodeFile file = iip.getLastINode().asFile();
+    BlocksMapUpdateInfo collectedBlocks = new BlocksMapUpdateInfo();
+    boolean onBlockBoundary = unprotectedTruncate(fsn, iip, newLength,
+        collectedBlocks, mtime, null);
+
+    if (!onBlockBoundary) {
+      BlockInfo oldBlock = file.getLastBlock();
+      Block tBlk = prepareFileForTruncate(fsn, iip, clientName, clientMachine,
+          file.computeFileSize() - newLength, truncateBlock);
+      assert Block.matchingIdAndGenStamp(tBlk, truncateBlock) &&
+          tBlk.getNumBytes() == truncateBlock.getNumBytes() :
+          "Should be the same block.";
+      if (oldBlock.getBlockId() != tBlk.getBlockId()
+          && !file.isBlockInLatestSnapshot(oldBlock)) {
+        fsn.getBlockManager().removeBlockFromMap(oldBlock);
+      }
+    }
+    assert onBlockBoundary == (truncateBlock == null) :
+      "truncateBlock is null iff on block boundary: " + truncateBlock;
+    fsn.removeBlocksAndUpdateSafemodeTotal(collectedBlocks);
+  }
+
+  /**
+   * Convert current INode to UnderConstruction. Recreate lease. Create new
+   * block for the truncated copy. Schedule truncation of the replicas.
+   *
+   * @param fsn namespace
+   * @param iip inodes in the path containing the file
+   * @param leaseHolder lease holder
+   * @param clientMachine client machine info
+   * @param lastBlockDelta last block delta size
+   * @param newBlock new block
+   * @return the returned block will be written to editLog and passed back
+   *         into this method upon loading.
+   * @throws IOException
+   */
+  @VisibleForTesting
+  static Block prepareFileForTruncate(FSNamesystem fsn, INodesInPath iip,
+      String leaseHolder, String clientMachine, long lastBlockDelta,
+      Block newBlock) throws IOException {
+    assert fsn.hasWriteLock();
+
+    INodeFile file = iip.getLastINode().asFile();
+    file.recordModification(iip.getLatestSnapshotId());
+    file.toUnderConstruction(leaseHolder, clientMachine);
+    assert file.isUnderConstruction() : "inode should be under construction.";
+    fsn.getLeaseManager().addLease(
+        file.getFileUnderConstructionFeature().getClientName(), file.getId());
+    boolean shouldRecoverNow = (newBlock == null);
+    BlockInfo oldBlock = file.getLastBlock();
+    boolean shouldCopyOnTruncate = shouldCopyOnTruncate(fsn, file, oldBlock);
+    if (newBlock == null) {
+      newBlock = (shouldCopyOnTruncate) ? fsn.createNewBlock() : new Block(
+          oldBlock.getBlockId(), oldBlock.getNumBytes(),
+          fsn.nextGenerationStamp(fsn.getBlockIdManager().isLegacyBlock(
+              oldBlock)));
+    }
+
+    BlockInfoUnderConstruction truncatedBlockUC;
+    if (shouldCopyOnTruncate) {
+      // Add new truncateBlock into blocksMap and
+      // use oldBlock as a source for copy-on-truncate recovery
+      truncatedBlockUC = new BlockInfoUnderConstructionContiguous(newBlock,
+          file.getPreferredBlockReplication());
+      truncatedBlockUC.setNumBytes(oldBlock.getNumBytes() - lastBlockDelta);
+      truncatedBlockUC.setTruncateBlock(oldBlock);
+      file.setLastBlock(truncatedBlockUC,
+          fsn.getBlockManager().getStorages(oldBlock));
+      fsn.getBlockManager().addBlockCollection(truncatedBlockUC, file);
+
+      NameNode.stateChangeLog.debug(
+          "BLOCK* prepareFileForTruncate: Scheduling copy-on-truncate to new"
+              + " size {}  new block {} old block {}",
+          truncatedBlockUC.getNumBytes(), newBlock,
+          truncatedBlockUC.getTruncateBlock());
+    } else {
+      // Use new generation stamp for in-place truncate recovery
+      fsn.getBlockManager().convertLastBlockToUnderConstruction(file,
+          lastBlockDelta);
+      oldBlock = file.getLastBlock();
+      assert !oldBlock.isComplete() : "oldBlock should be under construction";
+      truncatedBlockUC = (BlockInfoUnderConstruction) oldBlock;
+      truncatedBlockUC.setTruncateBlock(new Block(oldBlock));
+      truncatedBlockUC.getTruncateBlock().setNumBytes(
+          oldBlock.getNumBytes() - lastBlockDelta);
+      truncatedBlockUC.getTruncateBlock().setGenerationStamp(
+          newBlock.getGenerationStamp());
+
+      NameNode.stateChangeLog.debug(
+          "BLOCK* prepareFileForTruncate: {} Scheduling in-place block "
+              + "truncate to new size {}", truncatedBlockUC.getTruncateBlock()
+              .getNumBytes(), truncatedBlockUC);
+    }
+    if (shouldRecoverNow) {
+      truncatedBlockUC.initializeBlockRecovery(newBlock.getGenerationStamp());
+    }
+
+    return newBlock;
+  }
+
+  /**
+   * Truncate has the following properties:
+   * 1.) Any block deletions occur now.
+   * 2.) INode length is truncated now - new clients can only read up to
+   *     the truncated length.
+   * 3.) INode will be set to UC and lastBlock set to UNDER_RECOVERY.
+   * 4.) NN will trigger DN truncation recovery and waits for DNs to report.
+   * 5.) File is considered UNDER_RECOVERY until truncation recovery
+   *     completes.
+   * 6.) Soft and hard Lease expiration require truncation recovery to
+   *     complete.
+   *
+   * @return true if on the block boundary or false if recovery is need
+   */
+  private static boolean unprotectedTruncate(FSNamesystem fsn,
+      INodesInPath iip, long newLength, BlocksMapUpdateInfo collectedBlocks,
+      long mtime, QuotaCounts delta) throws IOException {
+    assert fsn.hasWriteLock();
+
+    INodeFile file = iip.getLastINode().asFile();
+    int latestSnapshot = iip.getLatestSnapshotId();
+    file.recordModification(latestSnapshot, true);
+
+    verifyQuotaForTruncate(fsn, iip, file, newLength, delta);
+
+    long remainingLength =
+        file.collectBlocksBeyondMax(newLength, collectedBlocks);
+    file.excludeSnapshotBlocks(latestSnapshot, collectedBlocks);
+    file.setModificationTime(mtime);
+    // return whether on a block boundary
+    return (remainingLength - newLength) == 0;
+  }
+
+  private static void verifyQuotaForTruncate(FSNamesystem fsn,
+      INodesInPath iip, INodeFile file, long newLength, QuotaCounts delta)
+      throws QuotaExceededException {
+    FSDirectory fsd = fsn.getFSDirectory();
+    if (!fsn.isImageLoaded() || fsd.shouldSkipQuotaChecks()) {
+      // Do not check quota if edit log is still being processed
+      return;
+    }
+    final BlockStoragePolicy policy = fsd.getBlockStoragePolicySuite()
+        .getPolicy(file.getStoragePolicyID());
+    file.computeQuotaDeltaForTruncate(newLength, policy, delta);
+    fsd.readLock();
+    try {
+      FSDirectory.verifyQuota(iip, iip.length() - 1, delta, null);
+    } finally {
+      fsd.readUnlock();
+    }
+  }
+
+  /**
+   * Defines if a replica needs to be copied on truncate or
+   * can be truncated in place.
+   */
+  private static boolean shouldCopyOnTruncate(FSNamesystem fsn, INodeFile file,
+      BlockInfo blk) {
+    if (!fsn.isUpgradeFinalized()) {
+      return true;
+    }
+    if (fsn.isRollingUpgrade()) {
+      return true;
+    }
+    return file.isBlockInLatestSnapshot(blk);
+  }
+
+  /**
+   * Result of truncate operation.
+   */
+  static class TruncateResult {
+    private final boolean result;
+    private final HdfsFileStatus stat;
+
+    public TruncateResult(boolean result, HdfsFileStatus stat) {
+      this.result = result;
+      this.stat = stat;
+    }
+
+    /**
+     * @return true if client does not need to wait for block recovery,
+     *          false if client needs to wait for block recovery.
+     */
+    boolean getResult() {
+      return result;
+    }
+
+    /**
+     * @return file information.
+     */
+    HdfsFileStatus getFileStatus() {
+      return stat;
+    }
+  }
+}

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

@@ -38,7 +38,6 @@ import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.XAttrHelper;
-import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
 import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.FSLimitException.MaxDirectoryItemsExceededException;
@@ -49,11 +48,9 @@ import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.protocol.SnapshotAccessControlException;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos;
 import org.apache.hadoop.hdfs.protocolPB.PBHelper;
-import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockStoragePolicySuite;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
-import org.apache.hadoop.hdfs.server.namenode.INode.BlocksMapUpdateInfo;
 import org.apache.hadoop.hdfs.util.ByteArray;
 import org.apache.hadoop.hdfs.util.EnumCounters;
 import org.apache.hadoop.security.AccessControlException;
@@ -907,98 +904,6 @@ public class FSDirectory implements Closeable {
     return inodeMap;
   }
 
-  /**
-   * FSEditLogLoader implementation.
-   * Unlike FSNamesystem.truncate, this will not schedule block recovery.
-   */
-  void unprotectedTruncate(String src, String clientName, String clientMachine,
-                           long newLength, long mtime, Block truncateBlock)
-      throws UnresolvedLinkException, QuotaExceededException,
-      SnapshotAccessControlException, IOException {
-    INodesInPath iip = getINodesInPath(src, true);
-    INodeFile file = iip.getLastINode().asFile();
-    BlocksMapUpdateInfo collectedBlocks = new BlocksMapUpdateInfo();
-    boolean onBlockBoundary =
-        unprotectedTruncate(iip, newLength, collectedBlocks, mtime, null);
-
-    if(! onBlockBoundary) {
-      BlockInfo oldBlock = file.getLastBlock();
-      Block tBlk =
-      getFSNamesystem().prepareFileForTruncate(iip,
-          clientName, clientMachine, file.computeFileSize() - newLength,
-          truncateBlock);
-      assert Block.matchingIdAndGenStamp(tBlk, truncateBlock) &&
-          tBlk.getNumBytes() == truncateBlock.getNumBytes() :
-          "Should be the same block.";
-      if(oldBlock.getBlockId() != tBlk.getBlockId() &&
-         !file.isBlockInLatestSnapshot(oldBlock)) {
-        getBlockManager().removeBlockFromMap(oldBlock);
-      }
-    }
-    assert onBlockBoundary == (truncateBlock == null) :
-      "truncateBlock is null iff on block boundary: " + truncateBlock;
-    getFSNamesystem().removeBlocksAndUpdateSafemodeTotal(collectedBlocks);
-  }
-
-  boolean truncate(INodesInPath iip, long newLength,
-                   BlocksMapUpdateInfo collectedBlocks,
-                   long mtime, QuotaCounts delta)
-      throws IOException {
-    writeLock();
-    try {
-      return unprotectedTruncate(iip, newLength, collectedBlocks, mtime, delta);
-    } finally {
-      writeUnlock();
-    }
-  }
-
-  /**
-   * Truncate has the following properties:
-   * 1.) Any block deletions occur now.
-   * 2.) INode length is truncated now – new clients can only read up to
-   * the truncated length.
-   * 3.) INode will be set to UC and lastBlock set to UNDER_RECOVERY.
-   * 4.) NN will trigger DN truncation recovery and waits for DNs to report.
-   * 5.) File is considered UNDER_RECOVERY until truncation recovery completes.
-   * 6.) Soft and hard Lease expiration require truncation recovery to complete.
-   *
-   * @return true if on the block boundary or false if recovery is need
-   */
-  boolean unprotectedTruncate(INodesInPath iip, long newLength,
-                              BlocksMapUpdateInfo collectedBlocks,
-                              long mtime, QuotaCounts delta) throws IOException {
-    assert hasWriteLock();
-    INodeFile file = iip.getLastINode().asFile();
-    int latestSnapshot = iip.getLatestSnapshotId();
-    file.recordModification(latestSnapshot, true);
-
-    verifyQuotaForTruncate(iip, file, newLength, delta);
-
-    long remainingLength =
-        file.collectBlocksBeyondMax(newLength, collectedBlocks);
-    file.excludeSnapshotBlocks(latestSnapshot, collectedBlocks);
-    file.setModificationTime(mtime);
-    // return whether on a block boundary
-    return (remainingLength - newLength) == 0;
-  }
-
-  private void verifyQuotaForTruncate(INodesInPath iip, INodeFile file,
-      long newLength, QuotaCounts delta) throws QuotaExceededException {
-    if (!getFSNamesystem().isImageLoaded() || shouldSkipQuotaChecks()) {
-      // Do not check quota if edit log is still being processed
-      return;
-    }
-    final BlockStoragePolicy policy = getBlockStoragePolicySuite()
-        .getPolicy(file.getStoragePolicyID());
-    file.computeQuotaDeltaForTruncate(newLength, policy, delta);
-    readLock();
-    try {
-      verifyQuota(iip, iip.length() - 1, delta, null);
-    } finally {
-      readUnlock();
-    }
-  }
-
   /**
    * This method is always called with writeLock of FSDirectory held.
    */

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

@@ -901,9 +901,9 @@ public class FSEditLogLoader {
     }
     case OP_TRUNCATE: {
       TruncateOp truncateOp = (TruncateOp) op;
-      fsDir.unprotectedTruncate(truncateOp.src, truncateOp.clientName,
-          truncateOp.clientMachine, truncateOp.newLength, truncateOp.timestamp,
-          truncateOp.truncateBlock);
+      FSDirTruncateOp.unprotectedTruncate(fsNamesys, truncateOp.src,
+          truncateOp.clientName, truncateOp.clientMachine,
+          truncateOp.newLength, truncateOp.timestamp, truncateOp.truncateBlock);
       break;
     }
     case OP_SET_STORAGE_POLICY: {

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

@@ -201,7 +201,6 @@ import org.apache.hadoop.hdfs.server.blockmanagement.BlockCollection;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockIdManager;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstruction;
-import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoUnderConstructionContiguous;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
 import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager;
@@ -1831,218 +1830,44 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
    * block recovery to truncate the last block of the file.
    *
    * @return true if client does not need to wait for block recovery,
-   * false if client needs to wait for block recovery.
+   *         false if client needs to wait for block recovery.
    */
-  boolean truncate(String src, long newLength,
-                   String clientName, String clientMachine,
-                   long mtime)
-      throws IOException, UnresolvedLinkException {
+  boolean truncate(String src, long newLength, String clientName,
+      String clientMachine, long mtime) throws IOException,
+      UnresolvedLinkException {
+
     requireEffectiveLayoutVersionForFeature(Feature.TRUNCATE);
-    boolean ret;
+    final FSDirTruncateOp.TruncateResult r;
     try {
-      ret = truncateInt(src, newLength, clientName, clientMachine, mtime);
+      NameNode.stateChangeLog.debug(
+          "DIR* NameSystem.truncate: src={} newLength={}", src, newLength);
+      if (newLength < 0) {
+        throw new HadoopIllegalArgumentException(
+            "Cannot truncate to a negative file size: " + newLength + ".");
+      }
+      final FSPermissionChecker pc = getPermissionChecker();
+      checkOperation(OperationCategory.WRITE);
+      writeLock();
+      BlocksMapUpdateInfo toRemoveBlocks = new BlocksMapUpdateInfo();
+      try {
+        checkOperation(OperationCategory.WRITE);
+        checkNameNodeSafeMode("Cannot truncate for " + src);
+        r = FSDirTruncateOp.truncate(this, src, newLength, clientName,
+            clientMachine, mtime, toRemoveBlocks, pc);
+      } finally {
+        writeUnlock();
+      }
+      getEditLog().logSync();
+      if (!toRemoveBlocks.getToDeleteList().isEmpty()) {
+        removeBlocks(toRemoveBlocks);
+        toRemoveBlocks.clear();
+      }
+      logAuditEvent(true, "truncate", src, null, r.getFileStatus());
     } catch (AccessControlException e) {
       logAuditEvent(false, "truncate", src);
       throw e;
     }
-    return ret;
-  }
-
-  boolean truncateInt(String srcArg, long newLength,
-                      String clientName, String clientMachine,
-                      long mtime)
-      throws IOException, UnresolvedLinkException {
-    String src = srcArg;
-    NameNode.stateChangeLog.debug(
-        "DIR* NameSystem.truncate: src={} newLength={}", src, newLength);
-    if (newLength < 0) {
-      throw new HadoopIllegalArgumentException(
-          "Cannot truncate to a negative file size: " + newLength + ".");
-    }
-    HdfsFileStatus stat = null;
-    FSPermissionChecker pc = getPermissionChecker();
-    checkOperation(OperationCategory.WRITE);
-    boolean res;
-    byte[][] pathComponents = FSDirectory.getPathComponentsForReservedPath(src);
-    writeLock();
-    BlocksMapUpdateInfo toRemoveBlocks = new BlocksMapUpdateInfo();
-    try {
-      checkOperation(OperationCategory.WRITE);
-      checkNameNodeSafeMode("Cannot truncate for " + src);
-      src = dir.resolvePath(pc, src, pathComponents);
-      res = truncateInternal(src, newLength, clientName,
-          clientMachine, mtime, pc, toRemoveBlocks);
-      stat = dir.getAuditFileInfo(dir.getINodesInPath4Write(src, false));
-    } finally {
-      writeUnlock();
-    }
-    getEditLog().logSync();
-    if (!toRemoveBlocks.getToDeleteList().isEmpty()) {
-      removeBlocks(toRemoveBlocks);
-      toRemoveBlocks.clear();
-    }
-    logAuditEvent(true, "truncate", src, null, stat);
-    return res;
-  }
-
-  /**
-   * Truncate a file to a given size
-   * Update the count at each ancestor directory with quota
-   */
-  boolean truncateInternal(String src, long newLength,
-                           String clientName, String clientMachine,
-                           long mtime, FSPermissionChecker pc,
-                           BlocksMapUpdateInfo toRemoveBlocks)
-      throws IOException, UnresolvedLinkException {
-    assert hasWriteLock();
-    INodesInPath iip = dir.getINodesInPath4Write(src, true);
-    if (isPermissionEnabled) {
-      dir.checkPathAccess(pc, iip, FsAction.WRITE);
-    }
-    INodeFile file = INodeFile.valueOf(iip.getLastINode(), src);
-    final BlockStoragePolicy lpPolicy =
-        blockManager.getStoragePolicy("LAZY_PERSIST");
-
-    if (lpPolicy != null &&
-        lpPolicy.getId() == file.getStoragePolicyID()) {
-      throw new UnsupportedOperationException(
-          "Cannot truncate lazy persist file " + src);
-    }
-
-    // Check if the file is already being truncated with the same length
-    final BlockInfo last = file.getLastBlock();
-    if (last != null && last.getBlockUCState() == BlockUCState.UNDER_RECOVERY) {
-      final Block truncateBlock
-          = ((BlockInfoUnderConstruction)last).getTruncateBlock();
-      if (truncateBlock != null) {
-        final long truncateLength = file.computeFileSize(false, false)
-            + truncateBlock.getNumBytes();
-        if (newLength == truncateLength) {
-          return false;
-        }
-      }
-    }
-
-    // Opening an existing file for truncate. May need lease recovery.
-    recoverLeaseInternal(RecoverLeaseOp.TRUNCATE_FILE,
-        iip, src, clientName, clientMachine, false);
-    // Truncate length check.
-    long oldLength = file.computeFileSize();
-    if(oldLength == newLength) {
-      return true;
-    }
-    if(oldLength < newLength) {
-      throw new HadoopIllegalArgumentException(
-          "Cannot truncate to a larger file size. Current size: " + oldLength +
-              ", truncate size: " + newLength + ".");
-    }
-    // Perform INodeFile truncation.
-    final QuotaCounts delta = new QuotaCounts.Builder().build();
-    boolean onBlockBoundary = dir.truncate(iip, newLength, toRemoveBlocks,
-        mtime, delta);
-    Block truncateBlock = null;
-    if(!onBlockBoundary) {
-      // Open file for write, but don't log into edits
-      long lastBlockDelta = file.computeFileSize() - newLength;
-      assert lastBlockDelta > 0 : "delta is 0 only if on block bounday";
-      truncateBlock = prepareFileForTruncate(iip, clientName, clientMachine,
-          lastBlockDelta, null);
-    }
-
-    // update the quota: use the preferred block size for UC block
-    dir.writeLock();
-    try {
-      dir.updateCountNoQuotaCheck(iip, iip.length() - 1, delta);
-    } finally {
-      dir.writeUnlock();
-    }
-
-    getEditLog().logTruncate(src, clientName, clientMachine, newLength, mtime,
-        truncateBlock);
-    return onBlockBoundary;
-  }
-
-  /**
-   * Convert current INode to UnderConstruction.
-   * Recreate lease.
-   * Create new block for the truncated copy.
-   * Schedule truncation of the replicas.
-   *
-   * @return the returned block will be written to editLog and passed back into
-   * this method upon loading.
-   */
-  Block prepareFileForTruncate(INodesInPath iip,
-                               String leaseHolder,
-                               String clientMachine,
-                               long lastBlockDelta,
-                               Block newBlock)
-      throws IOException {
-    INodeFile file = iip.getLastINode().asFile();
-    file.recordModification(iip.getLatestSnapshotId());
-    file.toUnderConstruction(leaseHolder, clientMachine);
-    assert file.isUnderConstruction() : "inode should be under construction.";
-    leaseManager.addLease(
-        file.getFileUnderConstructionFeature().getClientName(), file.getId());
-    boolean shouldRecoverNow = (newBlock == null);
-    BlockInfo oldBlock = file.getLastBlock();
-    boolean shouldCopyOnTruncate = shouldCopyOnTruncate(file, oldBlock);
-    if(newBlock == null) {
-      newBlock = (shouldCopyOnTruncate) ? createNewBlock() :
-          new Block(oldBlock.getBlockId(), oldBlock.getNumBytes(),
-              nextGenerationStamp(blockIdManager.isLegacyBlock(oldBlock)));
-    }
-
-    BlockInfoUnderConstruction truncatedBlockUC;
-    if(shouldCopyOnTruncate) {
-      // Add new truncateBlock into blocksMap and
-      // use oldBlock as a source for copy-on-truncate recovery
-      truncatedBlockUC = new BlockInfoUnderConstructionContiguous(newBlock,
-          file.getPreferredBlockReplication());
-      truncatedBlockUC.setNumBytes(oldBlock.getNumBytes() - lastBlockDelta);
-      truncatedBlockUC.setTruncateBlock(oldBlock);
-      file.setLastBlock(truncatedBlockUC, blockManager.getStorages(oldBlock));
-      getBlockManager().addBlockCollection(truncatedBlockUC, file);
-
-      NameNode.stateChangeLog.debug(
-          "BLOCK* prepareFileForTruncate: Scheduling copy-on-truncate to new" +
-          " size {}  new block {} old block {}", truncatedBlockUC.getNumBytes(),
-          newBlock, truncatedBlockUC.getTruncateBlock());
-    } else {
-      // Use new generation stamp for in-place truncate recovery
-      blockManager.convertLastBlockToUnderConstruction(file, lastBlockDelta);
-      oldBlock = file.getLastBlock();
-      assert !oldBlock.isComplete() : "oldBlock should be under construction";
-      truncatedBlockUC = (BlockInfoUnderConstruction) oldBlock;
-      truncatedBlockUC.setTruncateBlock(new Block(oldBlock));
-      truncatedBlockUC.getTruncateBlock().setNumBytes(
-          oldBlock.getNumBytes() - lastBlockDelta);
-      truncatedBlockUC.getTruncateBlock().setGenerationStamp(
-          newBlock.getGenerationStamp());
-
-      NameNode.stateChangeLog.debug(
-          "BLOCK* prepareFileForTruncate: {} Scheduling in-place block " +
-          "truncate to new size {}",
-          truncatedBlockUC.getTruncateBlock().getNumBytes(), truncatedBlockUC);
-    }
-    if (shouldRecoverNow) {
-      truncatedBlockUC.initializeBlockRecovery(newBlock.getGenerationStamp());
-    }
-
-    return newBlock;
-  }
-
-  /**
-   * Defines if a replica needs to be copied on truncate or
-   * can be truncated in place.
-   */
-  boolean shouldCopyOnTruncate(INodeFile file, BlockInfo blk) {
-    if(!isUpgradeFinalized()) {
-      return true;
-    }
-    if (isRollingUpgrade()) {
-      return true;
-    }
-    return file.isBlockInLatestSnapshot(blk);
+    return r.getResult();
   }
 
   /**

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

@@ -1008,8 +1008,8 @@ public class TestFileTruncate {
     fsn.writeLock();
     try {
       Block oldBlock = file.getLastBlock();
-      Block truncateBlock =
-          fsn.prepareFileForTruncate(iip, client, clientMachine, 1, null);
+      Block truncateBlock = FSDirTruncateOp.prepareFileForTruncate(fsn, iip,
+          client, clientMachine, 1, null);
       // In-place truncate uses old block id with new genStamp.
       assertThat(truncateBlock.getBlockId(),
           is(equalTo(oldBlock.getBlockId())));
@@ -1041,8 +1041,8 @@ public class TestFileTruncate {
     fsn.writeLock();
     try {
       Block oldBlock = file.getLastBlock();
-      Block truncateBlock =
-          fsn.prepareFileForTruncate(iip, client, clientMachine, 1, null);
+      Block truncateBlock = FSDirTruncateOp.prepareFileForTruncate(fsn, iip,
+          client, clientMachine, 1, null);
       // Copy-on-write truncate makes new block with new id and genStamp
       assertThat(truncateBlock.getBlockId(),
           is(not(equalTo(oldBlock.getBlockId()))));