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/**
 * 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;

import org.apache.hadoop.ipc.RpcNoSuchMethodException;
import org.apache.hadoop.thirdparty.com.google.common.base.Preconditions;
import org.apache.hadoop.thirdparty.com.google.common.collect.Lists;
import org.apache.commons.collections.list.TreeList;
import org.apache.hadoop.fs.LeaseRecoverable;
import org.apache.hadoop.fs.SafeMode;

import org.apache.hadoop.classification.VisibleForTesting;
import org.apache.hadoop.HadoopIllegalArgumentException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.crypto.key.KeyProvider;
import org.apache.hadoop.crypto.key.KeyProviderTokenIssuer;
import org.apache.hadoop.fs.BatchListingOperations;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.BlockStoragePolicySpi;
import org.apache.hadoop.fs.CacheFlag;
import org.apache.hadoop.fs.CommonPathCapabilities;
import org.apache.hadoop.fs.ContentSummary;
import org.apache.hadoop.fs.CreateFlag;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FSDataOutputStreamBuilder;
import org.apache.hadoop.fs.FSLinkResolver;
import org.apache.hadoop.fs.FileAlreadyExistsException;
import org.apache.hadoop.fs.FileChecksum;
import org.apache.hadoop.fs.FileEncryptionInfo;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FileSystemLinkResolver;
import org.apache.hadoop.fs.FsServerDefaults;
import org.apache.hadoop.fs.FsStatus;
import org.apache.hadoop.fs.GlobalStorageStatistics;
import org.apache.hadoop.fs.GlobalStorageStatistics.StorageStatisticsProvider;
import org.apache.hadoop.fs.InvalidPathHandleException;
import org.apache.hadoop.fs.PartialListing;
import org.apache.hadoop.fs.MultipartUploaderBuilder;
import org.apache.hadoop.fs.PathHandle;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Options;
import org.apache.hadoop.fs.Options.ChecksumOpt;
import org.apache.hadoop.fs.Options.HandleOpt;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PathFilter;
import org.apache.hadoop.fs.QuotaUsage;
import org.apache.hadoop.fs.RemoteIterator;
import org.apache.hadoop.fs.SafeModeAction;
import org.apache.hadoop.fs.StorageStatistics;
import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.fs.UnresolvedLinkException;
import org.apache.hadoop.fs.UnsupportedFileSystemException;
import org.apache.hadoop.fs.XAttrSetFlag;
import org.apache.hadoop.fs.impl.FileSystemMultipartUploaderBuilder;
import org.apache.hadoop.fs.permission.AclEntry;
import org.apache.hadoop.fs.permission.AclStatus;
import org.apache.hadoop.fs.permission.FsAction;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.hdfs.DFSOpsCountStatistics.OpType;
import org.apache.hadoop.hdfs.client.DfsPathCapabilities;
import org.apache.hadoop.hdfs.client.HdfsClientConfigKeys;
import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;
import org.apache.hadoop.hdfs.client.impl.CorruptFileBlockIterator;
import org.apache.hadoop.hdfs.protocol.AddErasureCodingPolicyResponse;
import org.apache.hadoop.hdfs.protocol.BatchedDirectoryListing;
import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
import org.apache.hadoop.hdfs.protocol.CacheDirectiveEntry;
import org.apache.hadoop.hdfs.protocol.CacheDirectiveInfo;
import org.apache.hadoop.hdfs.protocol.CachePoolEntry;
import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
import org.apache.hadoop.hdfs.protocol.ClientProtocol;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.hdfs.protocol.DirectoryListing;
import org.apache.hadoop.hdfs.protocol.ECTopologyVerifierResult;
import org.apache.hadoop.hdfs.protocol.HdfsPartialListing;
import org.apache.hadoop.hdfs.protocol.EncryptionZone;
import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
import org.apache.hadoop.hdfs.protocol.HdfsConstants.ReencryptAction;
import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
import org.apache.hadoop.hdfs.protocol.HdfsPathHandle;
import org.apache.hadoop.hdfs.protocol.HdfsLocatedFileStatus;
import org.apache.hadoop.hdfs.protocol.OpenFileEntry;
import org.apache.hadoop.hdfs.protocol.OpenFilesIterator.OpenFilesType;
import org.apache.hadoop.hdfs.protocol.ZoneReencryptionStatus;
import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
import org.apache.hadoop.hdfs.protocol.SnapshotDiffReportListing;
import org.apache.hadoop.hdfs.protocol.SnapshotDiffReportListing.DiffReportListingEntry;
import org.apache.hadoop.hdfs.client.impl.SnapshotDiffReportGenerator;
import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.security.token.DelegationTokenIssuer;
import org.apache.hadoop.util.ChunkedArrayList;
import org.apache.hadoop.util.Progressable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nonnull;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.EnumSet;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Optional;

import static org.apache.hadoop.fs.impl.PathCapabilitiesSupport.validatePathCapabilityArgs;

/****************************************************************
 * Implementation of the abstract FileSystem for the DFS system.
 * This object is the way end-user code interacts with a Hadoop
 * DistributedFileSystem.
 *
 *****************************************************************/
@InterfaceAudience.LimitedPrivate({ "MapReduce", "HBase" })
@InterfaceStability.Unstable
public class DistributedFileSystem extends FileSystem
    implements KeyProviderTokenIssuer, BatchListingOperations, LeaseRecoverable, SafeMode {
  private Path workingDir;
  private URI uri;

  DFSClient dfs;
  private boolean verifyChecksum = true;

  private DFSOpsCountStatistics storageStatistics;

  static{
    HdfsConfiguration.init();
  }

  public DistributedFileSystem() {
  }

  /**
   * Return the protocol scheme for the FileSystem.
   *
   * @return hdfs
   */
  @Override
  public String getScheme() {
    return HdfsConstants.HDFS_URI_SCHEME;
  }

  @Override
  public URI getUri() { return uri; }

  @Override
  public void initialize(URI uri, Configuration conf) throws IOException {
    super.initialize(uri, conf);
    setConf(conf);

    String host = uri.getHost();
    if (host == null) {
      throw new IOException("Incomplete HDFS URI, no host: "+ uri);
    }

    initDFSClient(uri, conf);
    this.uri = URI.create(uri.getScheme()+"://"+uri.getAuthority());
    this.workingDir = getHomeDirectory();

    storageStatistics = (DFSOpsCountStatistics) GlobalStorageStatistics.INSTANCE
        .put(DFSOpsCountStatistics.NAME,
          new StorageStatisticsProvider() {
            @Override
            public StorageStatistics provide() {
              return new DFSOpsCountStatistics();
            }
          });
  }

  void initDFSClient(URI theUri, Configuration conf) throws IOException {
    this.dfs =  new DFSClient(theUri, conf, statistics);
  }

  @Override
  public Path getWorkingDirectory() {
    return workingDir;
  }

  @Override
  public long getDefaultBlockSize() {
    return dfs.getConf().getDefaultBlockSize();
  }

  @Override
  public short getDefaultReplication() {
    return dfs.getConf().getDefaultReplication();
  }

  @Override
  public void setWorkingDirectory(Path dir) {
    String result = fixRelativePart(dir).toUri().getPath();
    if (!DFSUtilClient.isValidName(result)) {
      throw new IllegalArgumentException("Invalid DFS directory name " +
          result);
    }
    workingDir = fixRelativePart(dir);
  }

  @Override
  public Path getHomeDirectory() {
    return makeQualified(
        new Path(DFSUtilClient.getHomeDirectory(getConf(), dfs.ugi)));
  }

  /**
   * Returns the hedged read metrics object for this client.
   *
   * @return object of DFSHedgedReadMetrics
   */
  public DFSHedgedReadMetrics getHedgedReadMetrics() {
    return dfs.getHedgedReadMetrics();
  }

  /**
   * Checks that the passed URI belongs to this filesystem and returns
   * just the path component. Expects a URI with an absolute path.
   *
   * @param file URI with absolute path
   * @return path component of {file}
   * @throws IllegalArgumentException if URI does not belong to this DFS
   */
  String getPathName(Path file) {
    checkPath(file);
    String result = file.toUri().getPath();
    if (!DFSUtilClient.isValidName(result)) {
      throw new IllegalArgumentException("Pathname " + result + " from " +
          file+" is not a valid DFS filename.");
    }
    return result;
  }

  @Override
  public BlockLocation[] getFileBlockLocations(FileStatus file, long start,
      long len) throws IOException {
    if (file == null) {
      return null;
    }
    return getFileBlockLocations(file.getPath(), start, len);
  }

  /**
   * The returned BlockLocation will have different formats for replicated
   * and erasure coded file.
   * Please refer to
   * {@link FileSystem#getFileBlockLocations(FileStatus, long, long)}
   * for more details.
   */
  @Override
  public BlockLocation[] getFileBlockLocations(Path p,
      final long start, final long len) throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_FILE_BLOCK_LOCATIONS);
    final Path absF = fixRelativePart(p);
    return new FileSystemLinkResolver() {
      @Override
      public BlockLocation[] doCall(final Path p) throws IOException {
        return dfs.getBlockLocations(getPathName(p), start, len);
      }
      @Override
      public BlockLocation[] next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.getFileBlockLocations(p, start, len);
      }
    }.resolve(this, absF);
  }

  @Override
  public void setVerifyChecksum(boolean verifyChecksum) {
    this.verifyChecksum = verifyChecksum;
  }

  /**
   * Start the lease recovery of a file
   *
   * @param f a file
   * @return true if the file is already closed
   * @throws IOException if an error occurs
   */
  @Override
  public boolean recoverLease(final Path f) throws IOException {
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public Boolean doCall(final Path p) throws IOException{
        return dfs.recoverLease(getPathName(p));
      }
      @Override
      public Boolean next(final FileSystem fs, final Path p)
          throws IOException {
        if (fs instanceof DistributedFileSystem) {
          DistributedFileSystem myDfs = (DistributedFileSystem)fs;
          return myDfs.recoverLease(p);
        }
        throw new UnsupportedOperationException("Cannot recoverLease through" +
            " a symlink to a non-DistributedFileSystem: " + f + " -> " + p);
      }
    }.resolve(this, absF);
  }

  @Override
  public FSDataInputStream open(Path f, final int bufferSize)
      throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.OPEN);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public FSDataInputStream doCall(final Path p) throws IOException {
        final DFSInputStream dfsis =
            dfs.open(getPathName(p), bufferSize, verifyChecksum);
        try {
          return dfs.createWrappedInputStream(dfsis);
        } catch (IOException ex){
          dfsis.close();
          throw ex;
        }
      }
      @Override
      public FSDataInputStream next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.open(p, bufferSize);
      }
    }.resolve(this, absF);
  }

  /**
   * Opens an FSDataInputStream with the indicated file ID extracted from
   * the {@link PathHandle}.
   * @param fd Reference to entity in this FileSystem.
   * @param bufferSize the size of the buffer to be used.
   * @throws InvalidPathHandleException If PathHandle constraints do not hold
   * @throws IOException On I/O errors
   */
  @Override
  public FSDataInputStream open(PathHandle fd, int bufferSize)
      throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.OPEN);
    if (!(fd instanceof HdfsPathHandle)) {
      fd = new HdfsPathHandle(fd.bytes());
    }
    HdfsPathHandle id = (HdfsPathHandle) fd;
    final DFSInputStream dfsis = dfs.open(id, bufferSize, verifyChecksum);
    return dfs.createWrappedInputStream(dfsis);
  }

  /**
   * Create a handle to an HDFS file.
   * @param st HdfsFileStatus instance from NameNode
   * @param opts Standard handle arguments
   * @throws IllegalArgumentException If the FileStatus instance refers to a
   * directory, symlink, or another namesystem.
   * @throws UnsupportedOperationException If opts are not specified or both
   * data and location are not allowed to change.
   * @return A handle to the file.
   */
  @Override
  protected HdfsPathHandle createPathHandle(FileStatus st, HandleOpt... opts) {
    if (!(st instanceof HdfsFileStatus)) {
      throw new IllegalArgumentException("Invalid FileStatus "
          + st.getClass().getSimpleName());
    }
    if (st.isDirectory() || st.isSymlink()) {
      throw new IllegalArgumentException("PathHandle only available for files");
    }
    if (!getUri().getAuthority().equals(st.getPath().toUri().getAuthority())) {
      throw new IllegalArgumentException("Wrong FileSystem: " + st.getPath());
    }
    HandleOpt.Data data = HandleOpt.getOpt(HandleOpt.Data.class, opts)
        .orElse(HandleOpt.changed(false));
    HandleOpt.Location loc = HandleOpt.getOpt(HandleOpt.Location.class, opts)
        .orElse(HandleOpt.moved(false));

    HdfsFileStatus hst = (HdfsFileStatus) st;
    final Path p;
    final Optional inodeId;
    if (loc.allowChange()) {
      p = DFSUtilClient.makePathFromFileId(hst.getFileId());
      inodeId = Optional.empty();
    } else {
      p = hst.getPath();
      inodeId = Optional.of(hst.getFileId());
    }
    final Optional mtime = !data.allowChange()
        ? Optional.of(hst.getModificationTime())
        : Optional.empty();
    return new HdfsPathHandle(getPathName(p), inodeId, mtime);
  }

  @Override
  public FSDataOutputStream append(Path f, final int bufferSize,
      final Progressable progress) throws IOException {
    return append(f, EnumSet.of(CreateFlag.APPEND), bufferSize, progress);
  }

  @Override
  public FSDataOutputStream append(Path f, final int bufferSize,
      final Progressable progress, boolean appendToNewBlock) throws IOException {
    EnumSet flag = EnumSet.of(CreateFlag.APPEND);
    if (appendToNewBlock) {
      flag.add(CreateFlag.NEW_BLOCK);
    }
    return append(f, flag, bufferSize, progress);
  }

  /**
   * Append to an existing file (optional operation).
   *
   * @param f the existing file to be appended.
   * @param flag Flags for the Append operation. CreateFlag.APPEND is mandatory
   *          to be present.
   * @param bufferSize the size of the buffer to be used.
   * @param progress for reporting progress if it is not null.
   * @return Returns instance of {@link FSDataOutputStream}
   * @throws IOException
   */
  public FSDataOutputStream append(Path f, final EnumSet flag,
      final int bufferSize, final Progressable progress) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.APPEND);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public FSDataOutputStream doCall(final Path p)
          throws IOException {
        return dfs.append(getPathName(p), bufferSize, flag, progress,
            statistics);
      }
      @Override
      public FSDataOutputStream next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.append(p, bufferSize);
      }
    }.resolve(this, absF);
  }

  /**
   * Append to an existing file (optional operation).
   *
   * @param f the existing file to be appended.
   * @param flag Flags for the Append operation. CreateFlag.APPEND is mandatory
   *          to be present.
   * @param bufferSize the size of the buffer to be used.
   * @param progress for reporting progress if it is not null.
   * @param favoredNodes Favored nodes for new blocks
   * @return Returns instance of {@link FSDataOutputStream}
   * @throws IOException
   */
  public FSDataOutputStream append(Path f, final EnumSet flag,
      final int bufferSize, final Progressable progress,
      final InetSocketAddress[] favoredNodes) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.APPEND);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public FSDataOutputStream doCall(final Path p)
          throws IOException {
        return dfs.append(getPathName(p), bufferSize, flag, progress,
            statistics, favoredNodes);
      }
      @Override
      public FSDataOutputStream next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.append(p, bufferSize);
      }
    }.resolve(this, absF);
  }

  @Override
  public FSDataOutputStream create(Path f, FsPermission permission,
      boolean overwrite, int bufferSize, short replication, long blockSize,
      Progressable progress) throws IOException {
    return this.create(f, permission,
        overwrite ? EnumSet.of(CreateFlag.CREATE, CreateFlag.OVERWRITE)
            : EnumSet.of(CreateFlag.CREATE), bufferSize, replication,
        blockSize, progress, null);
  }

  /**
   * Same as
   * {@link #create(Path, FsPermission, boolean, int, short, long,
   * Progressable)} with the addition of favoredNodes that is a hint to
   * where the namenode should place the file blocks.
   * The favored nodes hint is not persisted in HDFS. Hence it may be honored
   * at the creation time only. And with favored nodes, blocks will be pinned
   * on the datanodes to prevent balancing move the block. HDFS could move the
   * blocks during replication, to move the blocks from favored nodes. A value
   * of null means no favored nodes for this create
   */
  public HdfsDataOutputStream create(final Path f,
      final FsPermission permission, final boolean overwrite,
      final int bufferSize, final short replication, final long blockSize,
      final Progressable progress, final InetSocketAddress[] favoredNodes)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.CREATE);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public HdfsDataOutputStream doCall(final Path p) throws IOException {
        final DFSOutputStream out = dfs.create(getPathName(f), permission,
            overwrite ? EnumSet.of(CreateFlag.CREATE, CreateFlag.OVERWRITE)
                : EnumSet.of(CreateFlag.CREATE),
            true, replication, blockSize, progress, bufferSize, null,
            favoredNodes);
        return safelyCreateWrappedOutputStream(out);
      }
      @Override
      public HdfsDataOutputStream next(final FileSystem fs, final Path p)
          throws IOException {
        if (fs instanceof DistributedFileSystem) {
          DistributedFileSystem myDfs = (DistributedFileSystem)fs;
          return myDfs.create(p, permission, overwrite, bufferSize, replication,
              blockSize, progress, favoredNodes);
        }
        throw new UnsupportedOperationException("Cannot create with" +
            " favoredNodes through a symlink to a non-DistributedFileSystem: "
            + f + " -> " + p);
      }
    }.resolve(this, absF);
  }

  @Override
  public FSDataOutputStream create(final Path f, final FsPermission permission,
      final EnumSet cflags, final int bufferSize,
      final short replication, final long blockSize,
      final Progressable progress, final ChecksumOpt checksumOpt)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.CREATE);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public FSDataOutputStream doCall(final Path p) throws IOException {
        final DFSOutputStream dfsos = dfs.create(getPathName(p), permission,
            cflags, replication, blockSize, progress, bufferSize,
            checksumOpt);
        return safelyCreateWrappedOutputStream(dfsos);
      }
      @Override
      public FSDataOutputStream next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.create(p, permission, cflags, bufferSize,
            replication, blockSize, progress, checksumOpt);
      }
    }.resolve(this, absF);
  }

  /**
   * Same as
   * {@link #create(Path, FsPermission, EnumSet, int, short, long,
   * Progressable, ChecksumOpt)} with a few additions. First, addition of
   * favoredNodes that is a hint to where the namenode should place the file
   * blocks. The favored nodes hint is not persisted in HDFS. Hence it may be
   * honored at the creation time only. And with favored nodes, blocks will be
   * pinned on the datanodes to prevent balancing move the block. HDFS could
   * move the blocks during replication, to move the blocks from favored nodes.
   * A value of null means no favored nodes for this create.
   * The second addition is ecPolicyName. A non-null ecPolicyName specifies an
   * explicit erasure coding policy for this file, overriding the inherited
   * policy. A null ecPolicyName means the file will inherit its EC policy or
   * replication policy from its ancestor (the default).
   * ecPolicyName and SHOULD_REPLICATE CreateFlag are mutually exclusive. It's
   * invalid to set both SHOULD_REPLICATE and a non-null ecPolicyName.
   * The third addition is storagePolicyName. A non-null storage Policy
   * specifies an explicit storage policy for this file, overriding the
   * inherited policy.
   *
   */
  private HdfsDataOutputStream create(final Path f,
      final FsPermission permission, final EnumSet flag,
      final int bufferSize, final short replication, final long blockSize,
      final Progressable progress, final ChecksumOpt checksumOpt,
      final InetSocketAddress[] favoredNodes, final String ecPolicyName,
      final String storagePolicy)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.CREATE);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public HdfsDataOutputStream doCall(final Path p) throws IOException {
        final DFSOutputStream out = dfs.create(getPathName(f), permission,
            flag, true, replication, blockSize, progress, bufferSize,
            checksumOpt, favoredNodes, ecPolicyName, storagePolicy);
        return safelyCreateWrappedOutputStream(out);
      }
      @Override
      public HdfsDataOutputStream next(final FileSystem fs, final Path p)
          throws IOException {
        if (fs instanceof DistributedFileSystem) {
          DistributedFileSystem myDfs = (DistributedFileSystem)fs;
          return myDfs.create(p, permission, flag, bufferSize, replication,
              blockSize, progress, checksumOpt, favoredNodes, ecPolicyName,
              storagePolicy);
        }
        throw new UnsupportedOperationException("Cannot create with" +
            " favoredNodes through a symlink to a non-DistributedFileSystem: "
            + f + " -> " + p);
      }
    }.resolve(this, absF);
  }

  @Override
  protected HdfsDataOutputStream primitiveCreate(Path f,
      FsPermission absolutePermission, EnumSet flag, int bufferSize,
      short replication, long blockSize, Progressable progress,
      ChecksumOpt checksumOpt) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.PRIMITIVE_CREATE);
    final DFSOutputStream dfsos = dfs.primitiveCreate(
        getPathName(fixRelativePart(f)),
        absolutePermission, flag, true, replication, blockSize,
        progress, bufferSize, checksumOpt);
    return safelyCreateWrappedOutputStream(dfsos);
  }

  /**
   * Similar to {@link #create(Path, FsPermission, EnumSet, int, short, long,
   * Progressable, ChecksumOpt, InetSocketAddress[], String)}, it provides a
   * HDFS-specific version of {@link #createNonRecursive(Path, FsPermission,
   * EnumSet, int, short, long, Progressable)} with a few additions.
   *
   * @see #create(Path, FsPermission, EnumSet, int, short, long, Progressable,
   * ChecksumOpt, InetSocketAddress[], String) for the descriptions of
   * additional parameters, i.e., favoredNodes, ecPolicyName and
   * storagePolicyName.
   */
  private HdfsDataOutputStream createNonRecursive(final Path f,
      final FsPermission permission, final EnumSet flag,
      final int bufferSize, final short replication, final long blockSize,
      final Progressable progress, final ChecksumOpt checksumOpt,
      final InetSocketAddress[] favoredNodes, final String ecPolicyName,
      final String storagePolicyName) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.CREATE);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public HdfsDataOutputStream doCall(final Path p) throws IOException {
        final DFSOutputStream out = dfs.create(getPathName(f), permission,
            flag, false, replication, blockSize, progress, bufferSize,
            checksumOpt, favoredNodes, ecPolicyName, storagePolicyName);
        return safelyCreateWrappedOutputStream(out);
      }
      @Override
      public HdfsDataOutputStream next(final FileSystem fs, final Path p)
          throws IOException {
        if (fs instanceof DistributedFileSystem) {
          DistributedFileSystem myDfs = (DistributedFileSystem)fs;
          return myDfs.createNonRecursive(p, permission, flag, bufferSize,
              replication, blockSize, progress, checksumOpt, favoredNodes,
              ecPolicyName, storagePolicyName);
        }
        throw new UnsupportedOperationException("Cannot create with" +
            " favoredNodes through a symlink to a non-DistributedFileSystem: "
            + f + " -> " + p);
      }
    }.resolve(this, absF);
  }

  /**
   * Same as create(), except fails if parent directory doesn't already exist.
   */
  @Override
  public FSDataOutputStream createNonRecursive(final Path f,
      final FsPermission permission, final EnumSet flag,
      final int bufferSize, final short replication, final long blockSize,
      final Progressable progress) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.CREATE_NON_RECURSIVE);
    if (flag.contains(CreateFlag.OVERWRITE)) {
      flag.add(CreateFlag.CREATE);
    }
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public FSDataOutputStream doCall(final Path p) throws IOException {
        final DFSOutputStream dfsos = dfs.create(getPathName(p), permission,
            flag, false, replication, blockSize, progress, bufferSize, null);
        return safelyCreateWrappedOutputStream(dfsos);
      }

      @Override
      public FSDataOutputStream next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.createNonRecursive(p, permission, flag, bufferSize,
            replication, blockSize, progress);
      }
    }.resolve(this, absF);
  }

  // Private helper to ensure the wrapped inner stream is closed safely
  // upon IOException throw during wrap.
  // Assuming the caller owns the inner stream which needs to be closed upon
  // wrap failure.
  private HdfsDataOutputStream safelyCreateWrappedOutputStream(
      DFSOutputStream dfsos) throws IOException {
    try {
      return dfs.createWrappedOutputStream(dfsos, statistics);
    } catch (IOException ex) {
      dfsos.close();
      throw ex;
    }
  }

  @Override
  public boolean setReplication(Path src, final short replication)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.SET_REPLICATION);
    Path absF = fixRelativePart(src);
    return new FileSystemLinkResolver() {
      @Override
      public Boolean doCall(final Path p) throws IOException {
        return dfs.setReplication(getPathName(p), replication);
      }
      @Override
      public Boolean next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.setReplication(p, replication);
      }
    }.resolve(this, absF);
  }

  /**
   * Set the source path to the specified storage policy.
   *
   * @param src The source path referring to either a directory or a file.
   * @param policyName The name of the storage policy.
   */
  @Override
  public void setStoragePolicy(final Path src, final String policyName)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.SET_STORAGE_POLICY);
    Path absF = fixRelativePart(src);
    new FileSystemLinkResolver() {
      @Override
      public Void doCall(final Path p) throws IOException {
        dfs.setStoragePolicy(getPathName(p), policyName);
        return null;
      }
      @Override
      public Void next(final FileSystem fs, final Path p)
          throws IOException {
        fs.setStoragePolicy(p, policyName);
        return null;
      }
    }.resolve(this, absF);
  }

  @Override
  public void unsetStoragePolicy(final Path src)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.UNSET_STORAGE_POLICY);
    Path absF = fixRelativePart(src);
    new FileSystemLinkResolver() {
      @Override
      public Void doCall(final Path p) throws IOException {
        dfs.unsetStoragePolicy(getPathName(p));
        return null;
      }
      @Override
      public Void next(final FileSystem fs, final Path p) throws IOException {
        if (fs instanceof DistributedFileSystem) {
          ((DistributedFileSystem) fs).unsetStoragePolicy(p);
          return null;
        } else {
          throw new UnsupportedOperationException(
              "Cannot perform unsetStoragePolicy on a "
                  + "non-DistributedFileSystem: " + src + " -> " + p);
        }
      }
    }.resolve(this, absF);
  }

  @Override
  public BlockStoragePolicySpi getStoragePolicy(Path path) throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_STORAGE_POLICY);
    Path absF = fixRelativePart(path);

    return new FileSystemLinkResolver() {
      @Override
      public BlockStoragePolicySpi doCall(final Path p) throws IOException {
        return getClient().getStoragePolicy(getPathName(p));
      }

      @Override
      public BlockStoragePolicySpi next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.getStoragePolicy(p);
      }
    }.resolve(this, absF);
  }

  @Override
  public Collection getAllStoragePolicies()
      throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_STORAGE_POLICIES);
    return Arrays.asList(dfs.getStoragePolicies());
  }

  /**
   * Returns number of bytes within blocks with future generation stamp. These
   * are bytes that will be potentially deleted if we forceExit from safe mode.
   *
   * @return number of bytes.
   */
  public long getBytesWithFutureGenerationStamps() throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_BYTES_WITH_FUTURE_GS);
    return dfs.getBytesInFutureBlocks();
  }

  /**
   * Deprecated. Prefer {@link FileSystem#getAllStoragePolicies()}
   * @throws IOException
   */
  @Deprecated
  public BlockStoragePolicy[] getStoragePolicies() throws IOException {
    return getAllStoragePolicies().toArray(new BlockStoragePolicy[0]);
  }

  /**
   * Move blocks from srcs to trg and delete srcs afterwards.
   * The file block sizes must be the same.
   *
   * @param trg existing file to append to
   * @param psrcs list of files (same block size, same replication)
   * @throws IOException
   */
  @Override
  public void concat(Path trg, Path [] psrcs) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.CONCAT);
    // Make target absolute
    Path absF = fixRelativePart(trg);
    // Make all srcs absolute
    Path[] srcs = new Path[psrcs.length];
    for (int i=0; i " + stat.getPath());
      }
      absF = fixRelativePart(stat.getPath());
      for (int i=0; i " + stat.getPath());
        }
        srcs[i] = fixRelativePart(stat.getPath());
      }
      // Try concat again. Can still race with another symlink.
      for (int i=0; i() {
        @Override
        public Boolean doCall(final Path p) throws IOException {
          return dfs.rename(getPathName(source), getPathName(p));
        }
        @Override
        public Boolean next(final FileSystem fs, final Path p)
            throws IOException {
          // Should just throw an error in FileSystem#checkPath
          return doCall(p);
        }
      }.resolve(this, absDst);
    }
  }

  /**
   * This rename operation is guaranteed to be atomic.
   */
  @SuppressWarnings("deprecation")
  @Override
  public void rename(Path src, Path dst, final Options.Rename... options)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.RENAME);
    final Path absSrc = fixRelativePart(src);
    final Path absDst = fixRelativePart(dst);
    // Try the rename without resolving first
    try {
      dfs.rename(getPathName(absSrc), getPathName(absDst), options);
    } catch (UnresolvedLinkException e) {
      // Fully resolve the source
      final Path source = getFileLinkStatus(absSrc).getPath();
      // Keep trying to resolve the destination
      new FileSystemLinkResolver() {
        @Override
        public Void doCall(final Path p) throws IOException {
          dfs.rename(getPathName(source), getPathName(p), options);
          return null;
        }
        @Override
        public Void next(final FileSystem fs, final Path p)
            throws IOException {
          // Should just throw an error in FileSystem#checkPath
          return doCall(p);
        }
      }.resolve(this, absDst);
    }
  }

  @Override
  public boolean truncate(Path f, final long newLength) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.TRUNCATE);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public Boolean doCall(final Path p) throws IOException {
        return dfs.truncate(getPathName(p), newLength);
      }
      @Override
      public Boolean next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.truncate(p, newLength);
      }
    }.resolve(this, absF);
  }

  @Override
  public boolean delete(Path f, final boolean recursive) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.DELETE);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public Boolean doCall(final Path p) throws IOException {
        return dfs.delete(getPathName(p), recursive);
      }
      @Override
      public Boolean next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.delete(p, recursive);
      }
    }.resolve(this, absF);
  }

  @Override
  public ContentSummary getContentSummary(Path f) throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_CONTENT_SUMMARY);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public ContentSummary doCall(final Path p) throws IOException {
        return dfs.getContentSummary(getPathName(p));
      }
      @Override
      public ContentSummary next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.getContentSummary(p);
      }
    }.resolve(this, absF);
  }

  @Override
  public QuotaUsage getQuotaUsage(Path f) throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_QUOTA_USAGE);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public QuotaUsage doCall(final Path p)
              throws IOException, UnresolvedLinkException {
        return dfs.getQuotaUsage(getPathName(p));
      }
      @Override
      public QuotaUsage next(final FileSystem fs, final Path p)
              throws IOException {
        return fs.getQuotaUsage(p);
      }
    }.resolve(this, absF);
  }

  /** Set a directory's quotas
   * @see org.apache.hadoop.hdfs.protocol.ClientProtocol#setQuota(String,
   * long, long, StorageType)
   */
  @Override
  public void setQuota(Path src, final long namespaceQuota,
      final long storagespaceQuota) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.SET_QUOTA_USAGE);
    Path absF = fixRelativePart(src);
    new FileSystemLinkResolver() {
      @Override
      public Void doCall(final Path p) throws IOException {
        dfs.setQuota(getPathName(p), namespaceQuota, storagespaceQuota);
        return null;
      }
      @Override
      public Void next(final FileSystem fs, final Path p)
          throws IOException {
        // setQuota is not defined in FileSystem, so we only can resolve
        // within this DFS
        return doCall(p);
      }
    }.resolve(this, absF);
  }

  /**
   * Set the per type storage quota of a directory.
   *
   * @param src target directory whose quota is to be modified.
   * @param type storage type of the specific storage type quota to be modified.
   * @param quota value of the specific storage type quota to be modified.
   * Maybe {@link HdfsConstants#QUOTA_RESET} to clear quota by storage type.
   */
  @Override
  public void setQuotaByStorageType(Path src, final StorageType type,
      final long quota)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.SET_QUOTA_BYTSTORAGEYPE);
    Path absF = fixRelativePart(src);
    new FileSystemLinkResolver() {
      @Override
      public Void doCall(final Path p) throws IOException {
        dfs.setQuotaByStorageType(getPathName(p), type, quota);
        return null;
      }
      @Override
      public Void next(final FileSystem fs, final Path p)
          throws IOException {
        // setQuotaByStorageType is not defined in FileSystem, so we only can
        // resolve within this DFS
        return doCall(p);
      }
    }.resolve(this, absF);
  }

  private FileStatus[] listStatusInternal(Path p) throws IOException {
    String src = getPathName(p);

    // fetch the first batch of entries in the directory
    DirectoryListing thisListing = dfs.listPaths(
        src, HdfsFileStatus.EMPTY_NAME);

    if (thisListing == null) { // the directory does not exist
      throw new FileNotFoundException("File " + p + " does not exist.");
    }

    HdfsFileStatus[] partialListing = thisListing.getPartialListing();
    if (!thisListing.hasMore()) { // got all entries of the directory
      FileStatus[] stats = new FileStatus[partialListing.length];
      for (int i = 0; i < partialListing.length; i++) {
        stats[i] = partialListing[i].makeQualified(getUri(), p);
      }
      statistics.incrementReadOps(1);
      storageStatistics.incrementOpCounter(OpType.LIST_STATUS);
      return stats;
    }

    // The directory size is too big that it needs to fetch more
    // estimate the total number of entries in the directory
    int totalNumEntries =
        partialListing.length + thisListing.getRemainingEntries();
    ArrayList listing =
        new ArrayList<>(totalNumEntries);
    // add the first batch of entries to the array list
    for (HdfsFileStatus fileStatus : partialListing) {
      listing.add(fileStatus.makeQualified(getUri(), p));
    }
    statistics.incrementLargeReadOps(1);
    storageStatistics.incrementOpCounter(OpType.LIST_STATUS);

    // now fetch more entries
    do {
      thisListing = dfs.listPaths(src, thisListing.getLastName());

      if (thisListing == null) { // the directory is deleted
        throw new FileNotFoundException("File " + p + " does not exist.");
      }

      partialListing = thisListing.getPartialListing();
      for (HdfsFileStatus fileStatus : partialListing) {
        listing.add(fileStatus.makeQualified(getUri(), p));
      }
      statistics.incrementLargeReadOps(1);
      storageStatistics.incrementOpCounter(OpType.LIST_STATUS);
    } while (thisListing.hasMore());

    return listing.toArray(new FileStatus[listing.size()]);
  }

  /**
   * List all the entries of a directory
   *
   * Note that this operation is not atomic for a large directory. The entries
   * of a directory may be fetched from NameNode multiple times. It only
   * guarantees that each name occurs once if a directory undergoes changes
   * between the calls.
   *
   * If any of the the immediate children of the given path f is a symlink, the
   * returned FileStatus object of that children would be represented as a
   * symlink. It will not be resolved to the target path and will not get the
   * target path FileStatus object. The target path will be available via
   * getSymlink on that children's FileStatus object. Since it represents as
   * symlink, isDirectory on that children's FileStatus will return false.
   *
   * If you want to get the FileStatus of target path for that children, you may
   * want to use GetFileStatus API with that children's symlink path. Please see
   * {@link DistributedFileSystem#getFileStatus(Path f)}
   */
  @Override
  public FileStatus[] listStatus(Path p) throws IOException {
    Path absF = fixRelativePart(p);
    return new FileSystemLinkResolver() {
      @Override
      public FileStatus[] doCall(final Path p) throws IOException {
        return listStatusInternal(p);
      }
      @Override
      public FileStatus[] next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.listStatus(p);
      }
    }.resolve(this, absF);
  }

  /**
   * The BlockLocation of returned LocatedFileStatus will have different
   * formats for replicated and erasure coded file.
   * Please refer to
   * {@link FileSystem#getFileBlockLocations(FileStatus, long, long)} for
   * more details.
   */
  @Override
  protected RemoteIterator listLocatedStatus(final Path p,
      final PathFilter filter)
      throws IOException {
    Path absF = fixRelativePart(p);
    return new FileSystemLinkResolver>() {
      @Override
      public RemoteIterator doCall(final Path p)
          throws IOException {
        return new DirListingIterator<>(p, filter, true);
      }

      @Override
      public RemoteIterator next(final FileSystem fs,
          final Path p) throws IOException {
        if (fs instanceof DistributedFileSystem) {
          return ((DistributedFileSystem)fs).listLocatedStatus(p, filter);
        }
        // symlink resolution for this methos does not work cross file systems
        // because it is a protected method.
        throw new IOException("Link resolution does not work with multiple " +
            "file systems for listLocatedStatus(): " + p);
      }
    }.resolve(this, absF);
  }


  /**
   * Returns a remote iterator so that followup calls are made on demand
   * while consuming the entries. This reduces memory consumption during
   * listing of a large directory.
   *
   * @param p target path
   * @return remote iterator
   */
  @Override
  public RemoteIterator listStatusIterator(final Path p)
      throws IOException {
    Path absF = fixRelativePart(p);
    return new FileSystemLinkResolver>() {
      @Override
      public RemoteIterator doCall(final Path p)
          throws IOException {
        return new DirListingIterator<>(p, false);
      }

      @Override
      public RemoteIterator next(final FileSystem fs, final Path p)
          throws IOException {
        return ((DistributedFileSystem)fs).listStatusIterator(p);
      }
    }.resolve(this, absF);

  }

  /**
   * This class defines an iterator that returns
   * the file status of each file/subdirectory of a directory
   *
   * if needLocation, status contains block location if it is a file
   * throws a RuntimeException with the error as its cause.
   *
   * @param  the type of the file status
   */
  private class  DirListingIterator
      implements RemoteIterator {
    private DirectoryListing thisListing;
    private int i;
    private Path p;
    private String src;
    private T curStat = null;
    private PathFilter filter;
    private boolean needLocation;

    private DirListingIterator(Path p, PathFilter filter,
        boolean needLocation) throws IOException {
      this.p = p;
      this.src = getPathName(p);
      this.filter = filter;
      this.needLocation = needLocation;
      // fetch the first batch of entries in the directory
      thisListing = dfs.listPaths(src, HdfsFileStatus.EMPTY_NAME,
          needLocation);
      statistics.incrementReadOps(1);
      if (needLocation) {
        storageStatistics.incrementOpCounter(OpType.LIST_LOCATED_STATUS);
      } else {
        storageStatistics.incrementOpCounter(OpType.LIST_STATUS);
      }
      if (thisListing == null) { // the directory does not exist
        throw new FileNotFoundException("File " + p + " does not exist.");
      }
      i = 0;
    }

    private DirListingIterator(Path p, boolean needLocation)
        throws IOException {
      this(p, null, needLocation);
    }

    @Override
    @SuppressWarnings("unchecked")
    public boolean hasNext() throws IOException {
      while (curStat == null && hasNextNoFilter()) {
        T next;
        HdfsFileStatus fileStat = thisListing.getPartialListing()[i++];
        if (needLocation) {
          next = (T)((HdfsLocatedFileStatus)fileStat)
              .makeQualifiedLocated(getUri(), p);
        } else {
          next = (T)fileStat.makeQualified(getUri(), p);
        }
        // apply filter if not null
        if (filter == null || filter.accept(next.getPath())) {
          curStat = next;
        }
      }
      return curStat != null;
    }

    /** Check if there is a next item before applying the given filter */
    private boolean hasNextNoFilter() throws IOException {
      if (thisListing == null) {
        return false;
      }
      if (i >= thisListing.getPartialListing().length
          && thisListing.hasMore()) {
        // current listing is exhausted & fetch a new listing
        thisListing = dfs.listPaths(src, thisListing.getLastName(),
            needLocation);
        statistics.incrementReadOps(1);
        if (thisListing == null) {
          throw new FileNotFoundException("File " + p + " does not exist.");
        }
        i = 0;
      }
      return (i < thisListing.getPartialListing().length);
    }

    @Override
    public T next() throws IOException {
      if (hasNext()) {
        T tmp = curStat;
        curStat = null;
        return tmp;
      }
      throw new java.util.NoSuchElementException("No more entry in " + p);
    }
  }

  @Override
  public RemoteIterator> batchedListStatusIterator(
      final List paths) throws IOException {
    List absPaths = Lists.newArrayListWithCapacity(paths.size());
    for (Path p : paths) {
      absPaths.add(fixRelativePart(p));
    }
    return new PartialListingIterator<>(absPaths, false);
  }

  @Override
  public RemoteIterator> batchedListLocatedStatusIterator(
      final List paths) throws IOException {
    List absPaths = Lists.newArrayListWithCapacity(paths.size());
    for (Path p : paths) {
      absPaths.add(fixRelativePart(p));
    }
    return new PartialListingIterator<>(absPaths, true);
  }

  private static final Logger LBI_LOG =
      LoggerFactory.getLogger(PartialListingIterator.class);

  private class PartialListingIterator
      implements RemoteIterator> {

    private List paths;
    private String[] srcs;
    private boolean needLocation;
    private BatchedDirectoryListing batchedListing;
    private int listingIdx = 0;

    PartialListingIterator(List paths, boolean needLocation)
        throws IOException {
      this.paths = paths;
      this.srcs = new String[paths.size()];
      for (int i = 0; i < paths.size(); i++) {
        this.srcs[i] = getPathName(paths.get(i));
      }
      this.needLocation = needLocation;

      // Do the first listing
      statistics.incrementReadOps(1);
      storageStatistics.incrementOpCounter(OpType.LIST_LOCATED_STATUS);
      batchedListing = dfs.batchedListPaths(
          srcs, HdfsFileStatus.EMPTY_NAME, needLocation);
      LBI_LOG.trace("Got batchedListing: {}", batchedListing);
      if (batchedListing == null) { // the directory does not exist
        throw new FileNotFoundException("One or more paths do not exist.");
      }
    }

    @Override
    public boolean hasNext() throws IOException {
      if (batchedListing == null) {
        return false;
      }
      // If we're done with the current batch, try to get the next batch
      if (listingIdx >= batchedListing.getListings().length) {
        if (!batchedListing.hasMore()) {
          LBI_LOG.trace("No more elements");
          return false;
        }
        batchedListing = dfs.batchedListPaths(
            srcs, batchedListing.getStartAfter(), needLocation);
        LBI_LOG.trace("Got batchedListing: {}", batchedListing);
        listingIdx = 0;
      }
      return listingIdx < batchedListing.getListings().length;
    }

    @Override
    @SuppressWarnings("unchecked")
    public PartialListing next() throws IOException {
      if (!hasNext()) {
        throw new NoSuchElementException("No more entries");
      }
      HdfsPartialListing listing = batchedListing.getListings()[listingIdx];
      listingIdx++;

      Path parent = paths.get(listing.getParentIdx());

      if (listing.getException() != null) {
        return new PartialListing<>(parent, listing.getException());
      }

      // Qualify paths for the client.
      List statuses = listing.getPartialListing();
      List qualifiedStatuses =
          Lists.newArrayListWithCapacity(statuses.size());

      for (HdfsFileStatus status : statuses) {
        if (needLocation) {
          qualifiedStatuses.add((T)((HdfsLocatedFileStatus) status)
              .makeQualifiedLocated(getUri(), parent));
        } else {
          qualifiedStatuses.add((T)status.makeQualified(getUri(), parent));
        }
      }

      return new PartialListing<>(parent, qualifiedStatuses);
    }
  }

  /**
   * Create a directory, only when the parent directories exist.
   *
   * See {@link FsPermission#applyUMask(FsPermission)} for details of how
   * the permission is applied.
   *
   * @param f           The path to create
   * @param permission  The permission.  See FsPermission#applyUMask for
   *                    details about how this is used to calculate the
   *                    effective permission.
   */
  public boolean mkdir(Path f, FsPermission permission) throws IOException {
    return mkdirsInternal(f, permission, false);
  }

  /**
   * Create a directory and its parent directories.
   *
   * See {@link FsPermission#applyUMask(FsPermission)} for details of how
   * the permission is applied.
   *
   * @param f           The path to create
   * @param permission  The permission.  See FsPermission#applyUMask for
   *                    details about how this is used to calculate the
   *                    effective permission.
   */
  @Override
  public boolean mkdirs(Path f, FsPermission permission) throws IOException {
    return mkdirsInternal(f, permission, true);
  }

  private boolean mkdirsInternal(Path f, final FsPermission permission,
      final boolean createParent) throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.MKDIRS);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public Boolean doCall(final Path p) throws IOException {
        return dfs.mkdirs(getPathName(p), permission, createParent);
      }

      @Override
      public Boolean next(final FileSystem fs, final Path p)
          throws IOException {
        // FileSystem doesn't have a non-recursive mkdir() method
        // Best we can do is error out
        if (!createParent) {
          throw new IOException("FileSystem does not support non-recursive"
              + "mkdir");
        }
        return fs.mkdirs(p, permission);
      }
    }.resolve(this, absF);
  }

  @SuppressWarnings("deprecation")
  @Override
  protected boolean primitiveMkdir(Path f, FsPermission absolutePermission)
      throws IOException {
    statistics.incrementWriteOps(1);
    storageStatistics.incrementOpCounter(OpType.PRIMITIVE_MKDIR);
    return dfs.primitiveMkdir(getPathName(f), absolutePermission);
  }


  @Override
  public void close() throws IOException {
    try {
      if (dfs != null) {
        dfs.closeOutputStreams(false);
      }
      super.close();
    } finally {
      if (dfs != null) {
        dfs.close();
      }
    }
  }

  @Override
  public String toString() {
    return "DFS[" + dfs + "]";
  }

  @InterfaceAudience.Private
  @VisibleForTesting
  public DFSClient getClient() {
    return dfs;
  }

  @Override
  public FsStatus getStatus(Path p) throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_STATUS);
    return dfs.getDiskStatus();
  }

  /**
   * Returns count of blocks with no good replicas left. Normally should be
   * zero.
   *
   * @throws IOException
   */
  public long getMissingBlocksCount() throws IOException {
    return dfs.getMissingBlocksCount();
  }

  /**
   * Returns count of blocks pending on deletion.
   *
   * @throws IOException
   */
  public long getPendingDeletionBlocksCount() throws IOException {
    return dfs.getPendingDeletionBlocksCount();
  }

  /**
   * Returns count of blocks with replication factor 1 and have
   * lost the only replica.
   *
   * @throws IOException
   */
  public long getMissingReplOneBlocksCount() throws IOException {
    return dfs.getMissingReplOneBlocksCount();
  }

  /**
   * Returns aggregated count of blocks with less redundancy.
   *
   * @throws IOException
   */
  public long getLowRedundancyBlocksCount() throws IOException {
    return dfs.getLowRedundancyBlocksCount();
  }

  /**
   * Returns count of blocks with at least one replica marked corrupt.
   *
   * @throws IOException
   */
  public long getCorruptBlocksCount() throws IOException {
    return dfs.getCorruptBlocksCount();
  }

  @Override
  public RemoteIterator listCorruptFileBlocks(final Path path)
      throws IOException {
    Path absF = fixRelativePart(path);
    return new FileSystemLinkResolver>() {
      @Override
      public RemoteIterator doCall(final Path path) throws IOException,
          UnresolvedLinkException {
        return new CorruptFileBlockIterator(dfs, path);
      }

      @Override
      public RemoteIterator next(final FileSystem fs, final Path path)
          throws IOException {
        return fs.listCorruptFileBlocks(path);
      }
    }.resolve(this, absF);
  }

  /** @return datanode statistics. */
  public DatanodeInfo[] getDataNodeStats() throws IOException {
    return getDataNodeStats(DatanodeReportType.ALL);
  }

  /** @return datanode statistics for the given type. */
  public DatanodeInfo[] getDataNodeStats(final DatanodeReportType type)
      throws IOException {
    return dfs.datanodeReport(type);
  }

  /**
   * Enter, leave or get safe mode.
   *
   * @see org.apache.hadoop.hdfs.protocol.ClientProtocol#setSafeMode(
   *    HdfsConstants.SafeModeAction,boolean)
   */
  @Override
  public boolean setSafeMode(SafeModeAction action)
      throws IOException {
    return setSafeMode(action, false);
  }

  /**
   * Enter, leave or get safe mode.
   *
   * @param action
   *          One of SafeModeAction.ENTER, SafeModeAction.LEAVE and
   *          SafeModeAction.GET.
   * @param isChecked
   *          If true check only for Active NNs status, else check first NN's
   *          status.
   */
  @Override
  @SuppressWarnings("deprecation")
  public boolean setSafeMode(SafeModeAction action, boolean isChecked)
      throws IOException {
    return this.setSafeMode(convertToClientProtocolSafeModeAction(action), isChecked);
  }

  /**
   * Translating the {@link SafeModeAction} into {@link HdfsConstants.SafeModeAction}
   * that is used by {@link DFSClient#setSafeMode(HdfsConstants.SafeModeAction, boolean)}.
   *
   * @param action any supported action listed in {@link SafeModeAction}.
   * @return the converted {@link HdfsConstants.SafeModeAction}.
   * @throws UnsupportedOperationException if the provided {@link SafeModeAction} cannot be
   *           translated.
   */
  private static HdfsConstants.SafeModeAction convertToClientProtocolSafeModeAction(
      SafeModeAction action) {
    switch (action) {
    case ENTER:
      return HdfsConstants.SafeModeAction.SAFEMODE_ENTER;
    case LEAVE:
      return HdfsConstants.SafeModeAction.SAFEMODE_LEAVE;
    case FORCE_EXIT:
      return HdfsConstants.SafeModeAction.SAFEMODE_FORCE_EXIT;
    case GET:
      return HdfsConstants.SafeModeAction.SAFEMODE_GET;
    default:
      throw new UnsupportedOperationException("Unsupported safe mode action " + action);
    }
  }

  /**
   * Enter, leave or get safe mode.
   *
   * @see org.apache.hadoop.hdfs.protocol.ClientProtocol#setSafeMode(HdfsConstants.SafeModeAction,
   * boolean)
   *
   * @deprecated please instead use {@link #setSafeMode(SafeModeAction)}.
   */
  @Deprecated
  public boolean setSafeMode(HdfsConstants.SafeModeAction action)
      throws IOException {
    return setSafeMode(action, false);
  }

  /**
   * Enter, leave or get safe mode.
   *
   * @param action
   *          One of SafeModeAction.ENTER, SafeModeAction.LEAVE and
   *          SafeModeAction.GET.
   * @param isChecked
   *          If true check only for Active NNs status, else check first NN's
   *          status.
   *
   * @see org.apache.hadoop.hdfs.protocol.ClientProtocol#setSafeMode(HdfsConstants.SafeModeAction,
   * boolean)
   *
   * @deprecated please instead use
   *               {@link DistributedFileSystem#setSafeMode(SafeModeAction, boolean)}.
   */
  @Deprecated
  public boolean setSafeMode(HdfsConstants.SafeModeAction action,
      boolean isChecked) throws IOException {
    return dfs.setSafeMode(action, isChecked);
  }

  /**
   * Save namespace image.
   *
   * @param timeWindow NameNode can ignore this command if the latest
   *                   checkpoint was done within the given time period (in
   *                   seconds).
   * @return true if a new checkpoint has been made
   * @see ClientProtocol#saveNamespace(long, long)
   */
  public boolean saveNamespace(long timeWindow, long txGap) throws IOException {
    return dfs.saveNamespace(timeWindow, txGap);
  }

  /**
   * Save namespace image. NameNode always does the checkpoint.
   */
  public void saveNamespace() throws IOException {
    saveNamespace(0, 0);
  }

  /**
   * Rolls the edit log on the active NameNode.
   * Requires super-user privileges.
   * @see org.apache.hadoop.hdfs.protocol.ClientProtocol#rollEdits()
   * @return the transaction ID of the newly created segment
   */
  public long rollEdits() throws IOException {
    return dfs.rollEdits();
  }

  /**
   * enable/disable/check restoreFaileStorage.
   *
   * @see org.apache.hadoop.hdfs.protocol.ClientProtocol#restoreFailedStorage(String arg)
   */
  public boolean restoreFailedStorage(String arg) throws IOException {
    return dfs.restoreFailedStorage(arg);
  }


  /**
   * Refreshes the list of hosts and excluded hosts from the configured
   * files.
   */
  public void refreshNodes() throws IOException {
    dfs.refreshNodes();
  }

  /**
   * Finalize previously upgraded files system state.
   * @throws IOException
   */
  public void finalizeUpgrade() throws IOException {
    dfs.finalizeUpgrade();
  }

  /**
   * Get status of upgrade - finalized or not.
   * @return true if upgrade is finalized or if no upgrade is in progress and
   * false otherwise.
   * @throws IOException
   */
  public boolean upgradeStatus() throws IOException {
    return dfs.upgradeStatus();
  }

  /**
   * Rolling upgrade: prepare/finalize/query.
   */
  public RollingUpgradeInfo rollingUpgrade(RollingUpgradeAction action)
      throws IOException {
    return dfs.rollingUpgrade(action);
  }

  /*
   * Requests the namenode to dump data strcutures into specified
   * file.
   */
  public void metaSave(String pathname) throws IOException {
    dfs.metaSave(pathname);
  }

  @Override
  public FsServerDefaults getServerDefaults() throws IOException {
    return dfs.getServerDefaults();
  }

  /**
   * Returns the stat information about the file.
   *
   * If the given path is a symlink, the path will be resolved to a target path
   * and it will get the resolved path's FileStatus object. It will not be
   * represented as a symlink and isDirectory API returns true if the resolved
   * path is a directory, false otherwise.
   *
   * @throws FileNotFoundException if the file does not exist.
   */
  @Override
  public FileStatus getFileStatus(Path f) throws IOException {
    statistics.incrementReadOps(1);
    storageStatistics.incrementOpCounter(OpType.GET_FILE_STATUS);
    Path absF = fixRelativePart(f);
    return new FileSystemLinkResolver() {
      @Override
      public FileStatus doCall(final Path p) throws IOException {
        HdfsFileStatus fi = dfs.getFileInfo(getPathName(p));
        if (fi != null) {
          return fi.makeQualified(getUri(), p);
        } else {
          throw new FileNotFoundException("File does not exist: " + p);
        }
      }
      @Override
      public FileStatus next(final FileSystem fs, final Path p)
          throws IOException {
        return fs.getFileStatus(p);
      }
    }.resolve(this, absF);
  }

  /**
   * Synchronize client metadata state with Active NameNode.
   * 

* In HA the client synchronizes its state with the Active NameNode * in order to guarantee subsequent read consistency from Observer Nodes. * @throws IOException */ @Override public void msync() throws IOException { dfs.msync(); } @SuppressWarnings("deprecation") @Override public void createSymlink(final Path target, final Path link, final boolean createParent) throws IOException { if (!FileSystem.areSymlinksEnabled()) { throw new UnsupportedOperationException("Symlinks not supported"); } statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.CREATE_SYM_LINK); final Path absF = fixRelativePart(link); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.createSymlink(target.toString(), getPathName(p), createParent); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.createSymlink(target, p, createParent); return null; } }.resolve(this, absF); } @Override public boolean supportsSymlinks() { return true; } @Override public FileStatus getFileLinkStatus(final Path f) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_FILE_LINK_STATUS); final Path absF = fixRelativePart(f); FileStatus status = new FileSystemLinkResolver() { @Override public FileStatus doCall(final Path p) throws IOException { HdfsFileStatus fi = dfs.getFileLinkInfo(getPathName(p)); if (fi != null) { return fi.makeQualified(getUri(), p); } else { throw new FileNotFoundException("File does not exist: " + p); } } @Override public FileStatus next(final FileSystem fs, final Path p) throws IOException { return fs.getFileLinkStatus(p); } }.resolve(this, absF); // Fully-qualify the symlink if (status.isSymlink()) { Path targetQual = FSLinkResolver.qualifySymlinkTarget(this.getUri(), status.getPath(), status.getSymlink()); status.setSymlink(targetQual); } return status; } @Override public Path getLinkTarget(final Path f) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_LINK_TARGET); final Path absF = fixRelativePart(f); return new FileSystemLinkResolver() { @Override public Path doCall(final Path p) throws IOException { HdfsFileStatus fi = dfs.getFileLinkInfo(getPathName(p)); if (fi != null) { return fi.makeQualified(getUri(), p).getSymlink(); } else { throw new FileNotFoundException("File does not exist: " + p); } } @Override public Path next(final FileSystem fs, final Path p) throws IOException { return fs.getLinkTarget(p); } }.resolve(this, absF); } @Override protected Path resolveLink(Path f) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.RESOLVE_LINK); String target = dfs.getLinkTarget(getPathName(fixRelativePart(f))); if (target == null) { throw new FileNotFoundException("File does not exist: " + f.toString()); } return new Path(target); } @Override public FileChecksum getFileChecksum(Path f) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_FILE_CHECKSUM); Path absF = fixRelativePart(f); return new FileSystemLinkResolver() { @Override public FileChecksum doCall(final Path p) throws IOException { return dfs.getFileChecksumWithCombineMode( getPathName(p), Long.MAX_VALUE); } @Override public FileChecksum next(final FileSystem fs, final Path p) throws IOException { return fs.getFileChecksum(p); } }.resolve(this, absF); } @Override public FileChecksum getFileChecksum(Path f, final long length) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_FILE_CHECKSUM); Path absF = fixRelativePart(f); return new FileSystemLinkResolver() { @Override public FileChecksum doCall(final Path p) throws IOException { return dfs.getFileChecksumWithCombineMode(getPathName(p), length); } @Override public FileChecksum next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { return fs.getFileChecksum(p, length); } else { throw new UnsupportedFileSystemException( "getFileChecksum(Path, long) is not supported by " + fs.getClass().getSimpleName()); } } }.resolve(this, absF); } @Override public void setPermission(Path p, final FsPermission permission ) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.SET_PERMISSION); Path absF = fixRelativePart(p); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.setPermission(getPathName(p), permission); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.setPermission(p, permission); return null; } }.resolve(this, absF); } @Override public void setOwner(Path p, final String username, final String groupname) throws IOException { if (username == null && groupname == null) { throw new IOException("username == null && groupname == null"); } statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.SET_OWNER); Path absF = fixRelativePart(p); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.setOwner(getPathName(p), username, groupname); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.setOwner(p, username, groupname); return null; } }.resolve(this, absF); } @Override public void setTimes(Path p, final long mtime, final long atime) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.SET_TIMES); Path absF = fixRelativePart(p); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.setTimes(getPathName(p), mtime, atime); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.setTimes(p, mtime, atime); return null; } }.resolve(this, absF); } @Override protected int getDefaultPort() { return HdfsClientConfigKeys.DFS_NAMENODE_RPC_PORT_DEFAULT; } @Override public Token getDelegationToken(String renewer) throws IOException { return dfs.getDelegationToken(renewer == null ? null : new Text(renewer)); } /** * Requests the namenode to tell all datanodes to use a new, non-persistent * bandwidth value for dfs.datanode.balance.bandwidthPerSec. * The bandwidth parameter is the max number of bytes per second of network * bandwidth to be used by a datanode during balancing. * * @param bandwidth Balancer bandwidth in bytes per second for all datanodes. * @throws IOException */ public void setBalancerBandwidth(long bandwidth) throws IOException { dfs.setBalancerBandwidth(bandwidth); } /** * Get a canonical service name for this file system. If the URI is logical, * the hostname part of the URI will be returned. * @return a service string that uniquely identifies this file system. */ @Override public String getCanonicalServiceName() { return dfs.getCanonicalServiceName(); } @Override protected URI canonicalizeUri(URI uri) { if (HAUtilClient.isLogicalUri(getConf(), uri)) { // Don't try to DNS-resolve logical URIs, since the 'authority' // portion isn't a proper hostname return uri; } else { return NetUtils.getCanonicalUri(uri, getDefaultPort()); } } /** * Utility function that returns if the NameNode is in safemode or not. In HA * mode, this API will return only ActiveNN's safemode status. * * @return true if NameNode is in safemode, false otherwise. * @throws IOException * when there is an issue communicating with the NameNode */ public boolean isInSafeMode() throws IOException { return setSafeMode(HdfsConstants.SafeModeAction.SAFEMODE_GET, true); } /** @see org.apache.hadoop.hdfs.client.HdfsAdmin#allowSnapshot(Path) */ public void allowSnapshot(final Path path) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.ALLOW_SNAPSHOT); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.allowSnapshot(getPathName(p)); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; myDfs.allowSnapshot(p); } else { throw new UnsupportedOperationException("Cannot perform snapshot" + " operations on a symlink to a non-DistributedFileSystem: " + path + " -> " + p); } return null; } }.resolve(this, absF); } /** @see org.apache.hadoop.hdfs.client.HdfsAdmin#disallowSnapshot(Path) */ public void disallowSnapshot(final Path path) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.DISALLOW_SNAPSHOT); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.disallowSnapshot(getPathName(p)); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; myDfs.disallowSnapshot(p); } else { throw new UnsupportedOperationException("Cannot perform snapshot" + " operations on a symlink to a non-DistributedFileSystem: " + path + " -> " + p); } return null; } }.resolve(this, absF); } @Override public Path createSnapshot(final Path path, final String snapshotName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.CREATE_SNAPSHOT); Path absF = fixRelativePart(path); return new FileSystemLinkResolver() { @Override public Path doCall(final Path p) throws IOException { return new Path(dfs.createSnapshot(getPathName(p), snapshotName)); } @Override public Path next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; return myDfs.createSnapshot(p); } else { throw new UnsupportedOperationException("Cannot perform snapshot" + " operations on a symlink to a non-DistributedFileSystem: " + path + " -> " + p); } } }.resolve(this, absF); } @Override public void renameSnapshot(final Path path, final String snapshotOldName, final String snapshotNewName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.RENAME_SNAPSHOT); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.renameSnapshot(getPathName(p), snapshotOldName, snapshotNewName); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; myDfs.renameSnapshot(p, snapshotOldName, snapshotNewName); } else { throw new UnsupportedOperationException("Cannot perform snapshot" + " operations on a symlink to a non-DistributedFileSystem: " + path + " -> " + p); } return null; } }.resolve(this, absF); } /** * Get the list of snapshottable directories that are owned * by the current user. Return all the snapshottable directories if the * current user is a super user. * @return The list of all the current snapshottable directories. * @throws IOException If an I/O error occurred. */ public SnapshottableDirectoryStatus[] getSnapshottableDirListing() throws IOException { statistics.incrementReadOps(1); storageStatistics .incrementOpCounter(OpType.GET_SNAPSHOTTABLE_DIRECTORY_LIST); return dfs.getSnapshottableDirListing(); } @Override public void deleteSnapshot(final Path snapshotDir, final String snapshotName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.DELETE_SNAPSHOT); Path absF = fixRelativePart(snapshotDir); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.deleteSnapshot(getPathName(p), snapshotName); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; myDfs.deleteSnapshot(p, snapshotName); } else { throw new UnsupportedOperationException("Cannot perform snapshot" + " operations on a symlink to a non-DistributedFileSystem: " + snapshotDir + " -> " + p); } return null; } }.resolve(this, absF); } /** * Returns a remote iterator so that followup calls are made on demand * while consuming the SnapshotDiffReportListing entries. * This reduces memory consumption overhead in case the snapshotDiffReport * is huge. * * @param snapshotDir * full path of the directory where snapshots are taken * @param fromSnapshot * snapshot name of the from point. Null indicates the current * tree * @param toSnapshot * snapshot name of the to point. Null indicates the current * tree. * @return Remote iterator */ public RemoteIterator snapshotDiffReportListingRemoteIterator( final Path snapshotDir, final String fromSnapshot, final String toSnapshot) throws IOException { Path absF = fixRelativePart(snapshotDir); return new FileSystemLinkResolver >() { @Override public RemoteIterator doCall(final Path p) throws IOException { if (!isValidSnapshotName(fromSnapshot) || !isValidSnapshotName( toSnapshot)) { throw new UnsupportedOperationException("Remote Iterator is" + "supported for snapshotDiffReport between two snapshots"); } return new SnapshotDiffReportListingIterator(getPathName(p), fromSnapshot, toSnapshot); } @Override public RemoteIterator next(final FileSystem fs, final Path p) throws IOException { return ((DistributedFileSystem) fs) .snapshotDiffReportListingRemoteIterator(p, fromSnapshot, toSnapshot); } }.resolve(this, absF); } /** * This class defines an iterator that returns * the SnapshotDiffReportListing for a snapshottable directory * between two given snapshots. */ private final class SnapshotDiffReportListingIterator implements RemoteIterator { private final String snapshotDir; private final String fromSnapshot; private final String toSnapshot; private byte[] startPath; private int index; private boolean hasNext = true; private SnapshotDiffReportListingIterator(String snapshotDir, String fromSnapshot, String toSnapshot) { this.snapshotDir = snapshotDir; this.fromSnapshot = fromSnapshot; this.toSnapshot = toSnapshot; this.startPath = DFSUtilClient.EMPTY_BYTES; this.index = -1; } @Override public boolean hasNext() { return hasNext; } @Override public SnapshotDiffReportListing next() throws IOException { if (!hasNext) { throw new java.util.NoSuchElementException( "No more entry in SnapshotDiffReport for " + snapshotDir); } final SnapshotDiffReportListing part = dfs.getSnapshotDiffReportListing(snapshotDir, fromSnapshot, toSnapshot, startPath, index); startPath = part.getLastPath(); index = part.getLastIndex(); hasNext = !(Arrays.equals(startPath, DFSUtilClient.EMPTY_BYTES) && index == -1); return part; } } private boolean isValidSnapshotName(String snapshotName) { // If any of the snapshots specified in the getSnapshotDiffReport call // is null or empty, it points to the current tree. return (snapshotName != null && !snapshotName.isEmpty()); } private SnapshotDiffReport getSnapshotDiffReportInternal( final String snapshotDir, final String fromSnapshot, final String toSnapshot) throws IOException { // In case the diff needs to be computed between a snapshot and the current // tree, we should not do iterative diffReport computation as the iterative // approach might fail if in between the rpc calls the current tree // changes in absence of the global fsn lock. if (!isValidSnapshotName(fromSnapshot) || !isValidSnapshotName( toSnapshot)) { return dfs.getSnapshotDiffReport(snapshotDir, fromSnapshot, toSnapshot); } byte[] startPath = DFSUtilClient.EMPTY_BYTES; int index = -1; SnapshotDiffReportGenerator snapshotDiffReport; List modifiedList = new TreeList(); List createdList = new ChunkedArrayList<>(); List deletedList = new ChunkedArrayList<>(); SnapshotDiffReportListing report; do { try { report = dfs.getSnapshotDiffReportListing(snapshotDir, fromSnapshot, toSnapshot, startPath, index); } catch (RpcNoSuchMethodException e) { // In case the server doesn't support getSnapshotDiffReportListing, // fallback to getSnapshotDiffReport. DFSClient.LOG.warn("Falling back to getSnapshotDiffReport {}", e.getMessage()); return dfs.getSnapshotDiffReport(snapshotDir, fromSnapshot, toSnapshot); } startPath = report.getLastPath(); index = report.getLastIndex(); modifiedList.addAll(report.getModifyList()); createdList.addAll(report.getCreateList()); deletedList.addAll(report.getDeleteList()); } while (!(Arrays.equals(startPath, DFSUtilClient.EMPTY_BYTES) && index == -1)); snapshotDiffReport = new SnapshotDiffReportGenerator(snapshotDir, fromSnapshot, toSnapshot, report.getIsFromEarlier(), modifiedList, createdList, deletedList); return snapshotDiffReport.generateReport(); } /** * Get the difference between two snapshots, or between a snapshot and the * current tree of a directory. * * @see DFSClient#getSnapshotDiffReportListing */ public SnapshotDiffReport getSnapshotDiffReport(final Path snapshotDir, final String fromSnapshot, final String toSnapshot) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_SNAPSHOT_DIFF); Path absF = fixRelativePart(snapshotDir); return new FileSystemLinkResolver() { @Override public SnapshotDiffReport doCall(final Path p) throws IOException { return getSnapshotDiffReportInternal(getPathName(p), fromSnapshot, toSnapshot); } @Override public SnapshotDiffReport next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; myDfs.getSnapshotDiffReport(p, fromSnapshot, toSnapshot); } else { throw new UnsupportedOperationException("Cannot perform snapshot" + " operations on a symlink to a non-DistributedFileSystem: " + snapshotDir + " -> " + p); } return null; } }.resolve(this, absF); } /** * Get the close status of a file * @param src The path to the file * * @return return true if file is closed * @throws FileNotFoundException if the file does not exist. * @throws IOException If an I/O error occurred */ @Override public boolean isFileClosed(final Path src) throws IOException { Path absF = fixRelativePart(src); return new FileSystemLinkResolver() { @Override public Boolean doCall(final Path p) throws IOException { return dfs.isFileClosed(getPathName(p)); } @Override public Boolean next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; return myDfs.isFileClosed(p); } else { throw new UnsupportedOperationException("Cannot call isFileClosed" + " on a symlink to a non-DistributedFileSystem: " + src + " -> " + p); } } }.resolve(this, absF); } /** * @see #addCacheDirective(CacheDirectiveInfo, EnumSet) */ public long addCacheDirective(CacheDirectiveInfo info) throws IOException { return addCacheDirective(info, EnumSet.noneOf(CacheFlag.class)); } /** * Add a new CacheDirective. * * @param info Information about a directive to add. * @param flags {@link CacheFlag}s to use for this operation. * @return the ID of the directive that was created. * @throws IOException if the directive could not be added */ public long addCacheDirective( CacheDirectiveInfo info, EnumSet flags) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.ADD_CACHE_DIRECTIVE); Preconditions.checkNotNull(info.getPath()); Path path = new Path(getPathName(fixRelativePart(info.getPath()))). makeQualified(getUri(), getWorkingDirectory()); return dfs.addCacheDirective( new CacheDirectiveInfo.Builder(info). setPath(path). build(), flags); } /** * @see #modifyCacheDirective(CacheDirectiveInfo, EnumSet) */ public void modifyCacheDirective(CacheDirectiveInfo info) throws IOException { modifyCacheDirective(info, EnumSet.noneOf(CacheFlag.class)); } /** * Modify a CacheDirective. * * @param info Information about the directive to modify. You must set the ID * to indicate which CacheDirective you want to modify. * @param flags {@link CacheFlag}s to use for this operation. * @throws IOException if the directive could not be modified */ public void modifyCacheDirective( CacheDirectiveInfo info, EnumSet flags) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.MODIFY_CACHE_DIRECTIVE); if (info.getPath() != null) { info = new CacheDirectiveInfo.Builder(info). setPath(new Path(getPathName(fixRelativePart(info.getPath()))). makeQualified(getUri(), getWorkingDirectory())).build(); } dfs.modifyCacheDirective(info, flags); } /** * Remove a CacheDirectiveInfo. * * @param id identifier of the CacheDirectiveInfo to remove * @throws IOException if the directive could not be removed */ public void removeCacheDirective(long id) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.REMOVE_CACHE_DIRECTIVE); dfs.removeCacheDirective(id); } /** * List cache directives. Incrementally fetches results from the server. * * @param filter Filter parameters to use when listing the directives, null to * list all directives visible to us. * @return A RemoteIterator which returns CacheDirectiveInfo objects. */ public RemoteIterator listCacheDirectives( CacheDirectiveInfo filter) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.LIST_CACHE_DIRECTIVE); if (filter == null) { filter = new CacheDirectiveInfo.Builder().build(); } if (filter.getPath() != null) { filter = new CacheDirectiveInfo.Builder(filter). setPath(new Path(getPathName(fixRelativePart(filter.getPath())))). build(); } final RemoteIterator iter = dfs.listCacheDirectives(filter); return new RemoteIterator() { @Override public boolean hasNext() throws IOException { return iter.hasNext(); } @Override public CacheDirectiveEntry next() throws IOException { // Although the paths we get back from the NameNode should always be // absolute, we call makeQualified to add the scheme and authority of // this DistributedFilesystem. CacheDirectiveEntry desc = iter.next(); CacheDirectiveInfo info = desc.getInfo(); Path p = info.getPath().makeQualified(getUri(), getWorkingDirectory()); return new CacheDirectiveEntry( new CacheDirectiveInfo.Builder(info).setPath(p).build(), desc.getStats()); } }; } /** * Add a cache pool. * * @param info * The request to add a cache pool. * @throws IOException * If the request could not be completed. */ public void addCachePool(CachePoolInfo info) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.ADD_CACHE_POOL); CachePoolInfo.validate(info); dfs.addCachePool(info); } /** * Modify an existing cache pool. * * @param info * The request to modify a cache pool. * @throws IOException * If the request could not be completed. */ public void modifyCachePool(CachePoolInfo info) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.MODIFY_CACHE_POOL); CachePoolInfo.validate(info); dfs.modifyCachePool(info); } /** * Remove a cache pool. * * @param poolName * Name of the cache pool to remove. * @throws IOException * if the cache pool did not exist, or could not be removed. */ public void removeCachePool(String poolName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.REMOVE_CACHE_POOL); CachePoolInfo.validateName(poolName); dfs.removeCachePool(poolName); } /** * List all cache pools. * * @return A remote iterator from which you can get CachePoolEntry objects. * Requests will be made as needed. * @throws IOException * If there was an error listing cache pools. */ public RemoteIterator listCachePools() throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.LIST_CACHE_POOL); return dfs.listCachePools(); } /** * {@inheritDoc} */ @Override public void modifyAclEntries(Path path, final List aclSpec) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.MODIFY_ACL_ENTRIES); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.modifyAclEntries(getPathName(p), aclSpec); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.modifyAclEntries(p, aclSpec); return null; } }.resolve(this, absF); } /** * {@inheritDoc} */ @Override public void removeAclEntries(Path path, final List aclSpec) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.REMOVE_ACL_ENTRIES); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.removeAclEntries(getPathName(p), aclSpec); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.removeAclEntries(p, aclSpec); return null; } }.resolve(this, absF); } /** * {@inheritDoc} */ @Override public void removeDefaultAcl(Path path) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.REMOVE_DEFAULT_ACL); final Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.removeDefaultAcl(getPathName(p)); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.removeDefaultAcl(p); return null; } }.resolve(this, absF); } /** * {@inheritDoc} */ @Override public void removeAcl(Path path) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.REMOVE_ACL); final Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.removeAcl(getPathName(p)); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.removeAcl(p); return null; } }.resolve(this, absF); } /** * {@inheritDoc} */ @Override public void setAcl(Path path, final List aclSpec) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.SET_ACL); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.setAcl(getPathName(p), aclSpec); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.setAcl(p, aclSpec); return null; } }.resolve(this, absF); } /** * {@inheritDoc} */ @Override public AclStatus getAclStatus(Path path) throws IOException { final Path absF = fixRelativePart(path); return new FileSystemLinkResolver() { @Override public AclStatus doCall(final Path p) throws IOException { return dfs.getAclStatus(getPathName(p)); } @Override public AclStatus next(final FileSystem fs, final Path p) throws IOException { return fs.getAclStatus(p); } }.resolve(this, absF); } /* HDFS only */ public void createEncryptionZone(final Path path, final String keyName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.CREATE_ENCRYPTION_ZONE); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.createEncryptionZone(getPathName(p), keyName); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem) fs; myDfs.createEncryptionZone(p, keyName); return null; } else { throw new UnsupportedOperationException( "Cannot call createEncryptionZone" + " on a symlink to a non-DistributedFileSystem: " + path + " -> " + p); } } }.resolve(this, absF); } /* HDFS only */ public EncryptionZone getEZForPath(final Path path) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_ENCRYPTION_ZONE); Preconditions.checkNotNull(path); Path absF = fixRelativePart(path); return new FileSystemLinkResolver() { @Override public EncryptionZone doCall(final Path p) throws IOException { return dfs.getEZForPath(getPathName(p)); } @Override public EncryptionZone next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem) fs; return myDfs.getEZForPath(p); } else { throw new UnsupportedOperationException( "Cannot call getEZForPath" + " on a symlink to a non-DistributedFileSystem: " + path + " -> " + p); } } }.resolve(this, absF); } /* HDFS only */ public RemoteIterator listEncryptionZones() throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.LIST_ENCRYPTION_ZONE); return dfs.listEncryptionZones(); } /* HDFS only */ public void reencryptEncryptionZone(final Path zone, final ReencryptAction action) throws IOException { final Path absF = fixRelativePart(zone); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.reencryptEncryptionZone(getPathName(p), action); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem) fs; myDfs.reencryptEncryptionZone(p, action); return null; } throw new UnsupportedOperationException( "Cannot call reencryptEncryptionZone" + " on a symlink to a non-DistributedFileSystem: " + zone + " -> " + p); } }.resolve(this, absF); } /* HDFS only */ public RemoteIterator listReencryptionStatus() throws IOException { return dfs.listReencryptionStatus(); } /* HDFS only */ public FileEncryptionInfo getFileEncryptionInfo(final Path path) throws IOException { Path absF = fixRelativePart(path); return new FileSystemLinkResolver() { @Override public FileEncryptionInfo doCall(final Path p) throws IOException { final HdfsFileStatus fi = dfs.getFileInfo(getPathName(p)); if (fi == null) { throw new FileNotFoundException("File does not exist: " + p); } return fi.getFileEncryptionInfo(); } @Override public FileEncryptionInfo next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; return myDfs.getFileEncryptionInfo(p); } throw new UnsupportedOperationException( "Cannot call getFileEncryptionInfo" + " on a symlink to a non-DistributedFileSystem: " + path + " -> " + p); } }.resolve(this, absF); } /* HDFS only */ public void provisionEZTrash(final Path path, final FsPermission trashPermission) throws IOException { Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(Path p) throws IOException { provisionEZTrash(getPathName(p), trashPermission); return null; } @Override public Void next(FileSystem fs, Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem)fs; myDfs.provisionEZTrash(p, trashPermission); return null; } throw new UnsupportedOperationException("Cannot provisionEZTrash " + "through a symlink to a non-DistributedFileSystem: " + fs + " -> " + p); } }.resolve(this, absF); } private void provisionEZTrash(String path, FsPermission trashPermission) throws IOException { // make sure the path is an EZ EncryptionZone ez = dfs.getEZForPath(path); if (ez == null) { throw new IllegalArgumentException(path + " is not an encryption zone."); } String ezPath = ez.getPath(); if (!path.toString().equals(ezPath)) { throw new IllegalArgumentException(path + " is not the root of an " + "encryption zone. Do you mean " + ez.getPath() + "?"); } // check if the trash directory exists Path trashPath = new Path(ez.getPath(), FileSystem.TRASH_PREFIX); try { FileStatus trashFileStatus = getFileStatus(trashPath); String errMessage = "Will not provision new trash directory for " + "encryption zone " + ez.getPath() + ". Path already exists."; if (!trashFileStatus.isDirectory()) { errMessage += "\r\n" + "Warning: " + trashPath.toString() + " is not a directory"; } if (!trashFileStatus.getPermission().equals(trashPermission)) { errMessage += "\r\n" + "Warning: the permission of " + trashPath.toString() + " is not " + trashPermission; } throw new FileAlreadyExistsException(errMessage); } catch (FileNotFoundException ignored) { // no trash path } // Update the permission bits mkdir(trashPath, trashPermission); setPermission(trashPath, trashPermission); } @Override public void setXAttr(Path path, final String name, final byte[] value, final EnumSet flag) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.SET_XATTR); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.setXAttr(getPathName(p), name, value, flag); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.setXAttr(p, name, value, flag); return null; } }.resolve(this, absF); } @Override public byte[] getXAttr(Path path, final String name) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_XATTR); final Path absF = fixRelativePart(path); return new FileSystemLinkResolver() { @Override public byte[] doCall(final Path p) throws IOException { return dfs.getXAttr(getPathName(p), name); } @Override public byte[] next(final FileSystem fs, final Path p) throws IOException { return fs.getXAttr(p, name); } }.resolve(this, absF); } @Override public Map getXAttrs(Path path) throws IOException { final Path absF = fixRelativePart(path); return new FileSystemLinkResolver>() { @Override public Map doCall(final Path p) throws IOException { return dfs.getXAttrs(getPathName(p)); } @Override public Map next(final FileSystem fs, final Path p) throws IOException { return fs.getXAttrs(p); } }.resolve(this, absF); } @Override public Map getXAttrs(Path path, final List names) throws IOException { final Path absF = fixRelativePart(path); return new FileSystemLinkResolver>() { @Override public Map doCall(final Path p) throws IOException { return dfs.getXAttrs(getPathName(p), names); } @Override public Map next(final FileSystem fs, final Path p) throws IOException { return fs.getXAttrs(p, names); } }.resolve(this, absF); } @Override public List listXAttrs(Path path) throws IOException { final Path absF = fixRelativePart(path); return new FileSystemLinkResolver>() { @Override public List doCall(final Path p) throws IOException { return dfs.listXAttrs(getPathName(p)); } @Override public List next(final FileSystem fs, final Path p) throws IOException { return fs.listXAttrs(p); } }.resolve(this, absF); } @Override public void removeXAttr(Path path, final String name) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.REMOVE_XATTR); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.removeXAttr(getPathName(p), name); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.removeXAttr(p, name); return null; } }.resolve(this, absF); } @Override public void access(Path path, final FsAction mode) throws IOException { final Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.checkAccess(getPathName(p), mode); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { fs.access(p, mode); return null; } }.resolve(this, absF); } @Override public URI getKeyProviderUri() throws IOException { return dfs.getKeyProviderUri(); } @Override public KeyProvider getKeyProvider() throws IOException { return dfs.getKeyProvider(); } @Override public DelegationTokenIssuer[] getAdditionalTokenIssuers() throws IOException { KeyProvider keyProvider = getKeyProvider(); if (keyProvider instanceof DelegationTokenIssuer) { return new DelegationTokenIssuer[]{(DelegationTokenIssuer)keyProvider}; } return null; } public DFSInotifyEventInputStream getInotifyEventStream() throws IOException { return dfs.getInotifyEventStream(); } public DFSInotifyEventInputStream getInotifyEventStream(long lastReadTxid) throws IOException { return dfs.getInotifyEventStream(lastReadTxid); } /** * Set the source path to the specified erasure coding policy. * * @param path The directory to set the policy * @param ecPolicyName The erasure coding policy name. * @throws IOException */ public void setErasureCodingPolicy(final Path path, final String ecPolicyName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.SET_EC_POLICY); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.setErasureCodingPolicy(getPathName(p), ecPolicyName); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem) fs; myDfs.setErasureCodingPolicy(p, ecPolicyName); return null; } throw new UnsupportedOperationException( "Cannot setErasureCodingPolicy through a symlink to a " + "non-DistributedFileSystem: " + path + " -> " + p); } }.resolve(this, absF); } /** * Set the source path to satisfy storage policy. * @param path The source path referring to either a directory or a file. * @throws IOException */ public void satisfyStoragePolicy(final Path path) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.SATISFY_STORAGE_POLICY); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(Path p) throws IOException { dfs.satisfyStoragePolicy(getPathName(p)); return null; } @Override public Void next(FileSystem fs, Path p) throws IOException { // DFS only if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem) fs; myDfs.satisfyStoragePolicy(p); return null; } throw new UnsupportedOperationException( "Cannot satisfyStoragePolicy through a symlink to a " + "non-DistributedFileSystem: " + path + " -> " + p); } }.resolve(this, absF); } /** * Get erasure coding policy information for the specified path * * @param path The path of the file or directory * @return Returns the policy information if file or directory on the path * is erasure coded, null otherwise. Null will be returned if directory or * file has REPLICATION policy. * @throws IOException */ public ErasureCodingPolicy getErasureCodingPolicy(final Path path) throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_EC_POLICY); Path absF = fixRelativePart(path); return new FileSystemLinkResolver() { @Override public ErasureCodingPolicy doCall(final Path p) throws IOException { return dfs.getErasureCodingPolicy(getPathName(p)); } @Override public ErasureCodingPolicy next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem) fs; return myDfs.getErasureCodingPolicy(p); } throw new UnsupportedOperationException( "Cannot getErasureCodingPolicy through a symlink to a " + "non-DistributedFileSystem: " + path + " -> " + p); } }.resolve(this, absF); } /** * Retrieve all the erasure coding policies supported by this file system, * including enabled, disabled and removed policies, but excluding * REPLICATION policy. * * @return all erasure coding policies supported by this file system. * @throws IOException */ public Collection getAllErasureCodingPolicies() throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_EC_POLICIES); return Arrays.asList(dfs.getErasureCodingPolicies()); } /** * Retrieve all the erasure coding codecs and coders supported by this file * system. * * @return all erasure coding codecs and coders supported by this file system. * @throws IOException */ public Map getAllErasureCodingCodecs() throws IOException { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_EC_CODECS); return dfs.getErasureCodingCodecs(); } /** * Add Erasure coding policies to HDFS. For each policy input, schema and * cellSize are musts, name and id are ignored. They will be automatically * created and assigned by Namenode once the policy is successfully added, * and will be returned in the response; policy states will be set to * DISABLED automatically. * * @param policies The user defined ec policy list to add. * @return Return the response list of adding operations. * @throws IOException */ public AddErasureCodingPolicyResponse[] addErasureCodingPolicies( ErasureCodingPolicy[] policies) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.ADD_EC_POLICY); return dfs.addErasureCodingPolicies(policies); } /** * Remove erasure coding policy. * * @param ecPolicyName The name of the policy to be removed. * @throws IOException */ public void removeErasureCodingPolicy(String ecPolicyName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.REMOVE_EC_POLICY); dfs.removeErasureCodingPolicy(ecPolicyName); } /** * Enable erasure coding policy. * * @param ecPolicyName The name of the policy to be enabled. * @throws IOException */ public void enableErasureCodingPolicy(String ecPolicyName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.ENABLE_EC_POLICY); dfs.enableErasureCodingPolicy(ecPolicyName); } /** * Disable erasure coding policy. * * @param ecPolicyName The name of the policy to be disabled. * @throws IOException */ public void disableErasureCodingPolicy(String ecPolicyName) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.DISABLE_EC_POLICY); dfs.disableErasureCodingPolicy(ecPolicyName); } /** * Unset the erasure coding policy from the source path. * * @param path The directory to unset the policy * @throws IOException */ public void unsetErasureCodingPolicy(final Path path) throws IOException { statistics.incrementWriteOps(1); storageStatistics.incrementOpCounter(OpType.UNSET_EC_POLICY); Path absF = fixRelativePart(path); new FileSystemLinkResolver() { @Override public Void doCall(final Path p) throws IOException { dfs.unsetErasureCodingPolicy(getPathName(p)); return null; } @Override public Void next(final FileSystem fs, final Path p) throws IOException { if (fs instanceof DistributedFileSystem) { DistributedFileSystem myDfs = (DistributedFileSystem) fs; myDfs.unsetErasureCodingPolicy(p); return null; } throw new UnsupportedOperationException( "Cannot unsetErasureCodingPolicy through a symlink to a " + "non-DistributedFileSystem: " + path + " -> " + p); } }.resolve(this, absF); } /** * Verifies if the given policies are supported in the given cluster setup. * If not policy is specified checks for all enabled policies. * @param policyNames name of policies. * @return the result if the given policies are supported in the cluster setup * @throws IOException */ public ECTopologyVerifierResult getECTopologyResultForPolicies( final String... policyNames) throws IOException { return dfs.getECTopologyResultForPolicies(policyNames); } /** * Get the root directory of Trash for a path in HDFS. * 1. File in encryption zone returns /ez1/.Trash/username * 2. File not in encryption zone, or encountered exception when checking * the encryption zone of the path, returns /users/username/.Trash * Caller appends either Current or checkpoint timestamp for trash destination * @param path the trash root of the path to be determined. * @return trash root */ @Override public Path getTrashRoot(Path path) { statistics.incrementReadOps(1); storageStatistics.incrementOpCounter(OpType.GET_TRASH_ROOT); try { if ((path == null) || !dfs.isHDFSEncryptionEnabled()) { return super.getTrashRoot(path); } } catch (IOException ioe) { DFSClient.LOG.warn("Exception while checking whether encryption zone is " + "supported", ioe); } String parentSrc = path.isRoot()? path.toUri().getPath():path.getParent().toUri().getPath(); try { EncryptionZone ez = dfs.getEZForPath(parentSrc); if ((ez != null)) { return this.makeQualified( new Path(DFSUtilClient.getEZTrashRoot(ez, dfs.ugi))); } } catch (IOException e) { DFSClient.LOG.warn("Exception in checking the encryption zone for the " + "path " + parentSrc + ". " + e.getMessage()); } return super.getTrashRoot(path); } /** * Get all the trash roots of HDFS for current user or for all the users. * 1. File deleted from non-encryption zone /user/username/.Trash * 2. File deleted from encryption zones * e.g., ez1 rooted at /ez1 has its trash root at /ez1/.Trash/$USER * @param allUsers return trashRoots of all users if true, used by emptier * @return trash roots of HDFS */ @Override public Collection getTrashRoots(boolean allUsers) { List ret = new ArrayList<>(); // Get normal trash roots ret.addAll(super.getTrashRoots(allUsers)); try { // Get EZ Trash roots final RemoteIterator it = dfs.listEncryptionZones(); while (it.hasNext()) { EncryptionZone ez = it.next(); Path ezTrashRoot = new Path(ez.getPath(), FileSystem.TRASH_PREFIX); if (!exists(ezTrashRoot)) { continue; } if (allUsers) { for (FileStatus candidate : listStatus(ezTrashRoot)) { if (exists(candidate.getPath())) { ret.add(candidate); } } } else { Path userTrash = new Path(DFSUtilClient.getEZTrashRoot(ez, dfs.ugi)); try { ret.add(getFileStatus(userTrash)); } catch (FileNotFoundException ignored) { } } } } catch (IOException e){ DFSClient.LOG.warn("Cannot get all encrypted trash roots", e); } return ret; } @Override protected Path fixRelativePart(Path p) { return super.fixRelativePart(p); } Statistics getFsStatistics() { return statistics; } DFSOpsCountStatistics getDFSOpsCountStatistics() { return storageStatistics; } /** * HdfsDataOutputStreamBuilder provides the HDFS-specific capabilities to * write file on HDFS. */ public static final class HdfsDataOutputStreamBuilder extends FSDataOutputStreamBuilder< FSDataOutputStream, HdfsDataOutputStreamBuilder> { private final DistributedFileSystem dfs; private InetSocketAddress[] favoredNodes = null; private String ecPolicyName = null; private String storagePolicyName = null; /** * Construct a HdfsDataOutputStream builder for a file. * @param dfs the {@link DistributedFileSystem} instance. * @param path the path of the file to create / append. */ private HdfsDataOutputStreamBuilder(DistributedFileSystem dfs, Path path) { super(dfs, path); this.dfs = dfs; } @Override public HdfsDataOutputStreamBuilder getThisBuilder() { return this; } private InetSocketAddress[] getFavoredNodes() { return favoredNodes; } /** * Set favored DataNodes. * @param nodes the addresses of the favored DataNodes. */ public HdfsDataOutputStreamBuilder favoredNodes( @Nonnull final InetSocketAddress[] nodes) { Preconditions.checkNotNull(nodes); favoredNodes = nodes.clone(); return this; } /** * Force closed blocks to disk. * * @see CreateFlag for the details. */ public HdfsDataOutputStreamBuilder syncBlock() { getFlags().add(CreateFlag.SYNC_BLOCK); return this; } /** * Create the block on transient storage if possible. * * @see CreateFlag for the details. */ public HdfsDataOutputStreamBuilder lazyPersist() { getFlags().add(CreateFlag.LAZY_PERSIST); return this; } /** * Append data to a new block instead of the end of the last partial block. * * @see CreateFlag for the details. */ public HdfsDataOutputStreamBuilder newBlock() { getFlags().add(CreateFlag.NEW_BLOCK); return this; } /** * Advise that a block replica NOT be written to the local DataNode. * * @see CreateFlag for the details. */ public HdfsDataOutputStreamBuilder noLocalWrite() { getFlags().add(CreateFlag.NO_LOCAL_WRITE); return this; } /** * Advise that a block replica NOT be written to the local rack DataNode. * * @see CreateFlag for the details. */ public HdfsDataOutputStreamBuilder noLocalRack() { getFlags().add(CreateFlag.NO_LOCAL_RACK); return this; } @VisibleForTesting String getStoragePolicyName() { return storagePolicyName; } /** * Enforce a file to follow the specified storage policy irrespective of the * storage policy of its parent directory. */ public HdfsDataOutputStreamBuilder storagePolicyName( @Nonnull final String policyName) { Preconditions.checkNotNull(policyName); storagePolicyName = policyName; return this; } @VisibleForTesting String getEcPolicyName() { return ecPolicyName; } /** * Enforce the file to be a striped file with erasure coding policy * 'policyName', no matter what its parent directory's replication * or erasure coding policy is. Don't call this function and * enforceReplicate() in the same builder since they have conflict * of interest. */ public HdfsDataOutputStreamBuilder ecPolicyName( @Nonnull final String policyName) { Preconditions.checkNotNull(policyName); ecPolicyName = policyName; return this; } @VisibleForTesting boolean shouldReplicate() { return getFlags().contains(CreateFlag.SHOULD_REPLICATE); } /** * Enforce the file to be a replicated file, no matter what its parent * directory's replication or erasure coding policy is. Don't call this * function and setEcPolicyName() in the same builder since they have * conflict of interest. */ public HdfsDataOutputStreamBuilder replicate() { getFlags().add(CreateFlag.SHOULD_REPLICATE); return this; } /** * Advise that the first block replica be written without regard to the * client locality. * * @see CreateFlag for the details. */ public HdfsDataOutputStreamBuilder ignoreClientLocality() { getFlags().add(CreateFlag.IGNORE_CLIENT_LOCALITY); return this; } @VisibleForTesting @Override protected EnumSet getFlags() { return super.getFlags(); } /** * Build HdfsDataOutputStream to write. * * @return a fully-initialized OutputStream. * @throws IOException on I/O errors. */ @Override public FSDataOutputStream build() throws IOException { if (getFlags().contains(CreateFlag.CREATE) || getFlags().contains(CreateFlag.OVERWRITE)) { if (isRecursive()) { return dfs.create(getPath(), getPermission(), getFlags(), getBufferSize(), getReplication(), getBlockSize(), getProgress(), getChecksumOpt(), getFavoredNodes(), getEcPolicyName(), getStoragePolicyName()); } else { return dfs.createNonRecursive(getPath(), getPermission(), getFlags(), getBufferSize(), getReplication(), getBlockSize(), getProgress(), getChecksumOpt(), getFavoredNodes(), getEcPolicyName(), getStoragePolicyName()); } } else if (getFlags().contains(CreateFlag.APPEND)) { return dfs.append(getPath(), getFlags(), getBufferSize(), getProgress(), getFavoredNodes()); } throw new HadoopIllegalArgumentException( "Must specify either create or append"); } } /** * Create a HdfsDataOutputStreamBuilder to create a file on DFS. * Similar to {@link #create(Path)}, file is overwritten by default. * * @param path the path of the file to create. * @return A HdfsDataOutputStreamBuilder for creating a file. */ @Override public HdfsDataOutputStreamBuilder createFile(Path path) { return new HdfsDataOutputStreamBuilder(this, path).create().overwrite(true); } /** * Returns a RemoteIterator which can be used to list all open files * currently managed by the NameNode. For large numbers of open files, * iterator will fetch the list in batches of configured size. *

* Since the list is fetched in batches, it does not represent a * consistent snapshot of the all open files. *

* This method can only be called by HDFS superusers. */ @Deprecated public RemoteIterator listOpenFiles() throws IOException { return dfs.listOpenFiles(); } @Deprecated public RemoteIterator listOpenFiles( EnumSet openFilesTypes) throws IOException { return dfs.listOpenFiles(openFilesTypes); } public RemoteIterator listOpenFiles( EnumSet openFilesTypes, String path) throws IOException { Path absF = fixRelativePart(new Path(path)); return dfs.listOpenFiles(openFilesTypes, getPathName(absF)); } /** * Create a {@link HdfsDataOutputStreamBuilder} to append a file on DFS. * * @param path file path. * @return A {@link HdfsDataOutputStreamBuilder} for appending a file. */ @Override public HdfsDataOutputStreamBuilder appendFile(Path path) { return new HdfsDataOutputStreamBuilder(this, path).append(); } /** * HDFS client capabilities. * Uses {@link DfsPathCapabilities} to keep {@code WebHdfsFileSystem} in sync. * {@inheritDoc} */ @Override public boolean hasPathCapability(final Path path, final String capability) throws IOException { // qualify the path to make sure that it refers to the current FS. final Path p = makeQualified(path); Optional cap = DfsPathCapabilities.hasPathCapability(p, capability); if (cap.isPresent()) { return cap.get(); } // this switch is for features which are in the DFS client but not // (yet/ever) in the WebHDFS API. switch (validatePathCapabilityArgs(path, capability)) { case CommonPathCapabilities.FS_EXPERIMENTAL_BATCH_LISTING: case CommonPathCapabilities.LEASE_RECOVERABLE: return true; default: // fall through } return super.hasPathCapability(p, capability); } @Override public MultipartUploaderBuilder createMultipartUploader(final Path basePath) throws IOException { return new FileSystemMultipartUploaderBuilder(this, basePath); } /** * Retrieve stats for slow running datanodes. * * @return An array of slow datanode info. * @throws IOException If an I/O error occurs. */ public DatanodeInfo[] getSlowDatanodeStats() throws IOException { return dfs.slowDatanodeReport(); } }





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