NfsCommitResponse.java

/**
 * Copyright 2016-2018 Dell Inc. or its subsidiaries. All rights reserved.
 *
 * <p>Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
 * except in compliance with the License. A copy of the License is located at
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 * <p>or in the "license" file accompanying this file. This file 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 com.emc.ecs.nfsclient.nfs;

import com.emc.ecs.nfsclient.rpc.RpcException;
import com.emc.ecs.nfsclient.rpc.Xdr;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The response, as specified by RFC 1813 (https://tools.ietf.org/html/rfc1813).
 *
 * <p>Procedure COMMIT forces or flushes data to stable storage that was previously written with a
 * WRITE procedure call with the stable field set to UNSTABLE.
 *
 * @author seibed
 */
public class NfsCommitResponse extends NfsResponseBase {

  private static final Logger _log = LoggerFactory.getLogger(NfsCommitResponse.class);

  /** Weak cache consistency data for the file. */
  private NfsWccData _fileWccData = new NfsWccData();

  /**
   * This is a cookie that the client can use to determine whether the server has rebooted between a
   * call to WRITE and a subsequent call to COMMIT. This cookie must be consistent during a single
   * boot session and must be unique between instances of the NFS version 3 protocol server where
   * uncommitted data may be lost.
   */
  private long _verf;

  /**
   * Creates the response, as specified by RFC 1813 (https://tools.ietf.org/html/rfc1813).
   *
   * <p>Procedure COMMIT forces or flushes data to stable storage that was previously written with a
   * WRITE procedure call with the stable field set to UNSTABLE.
   *
   * @param nfsVersion The NFS version number. This is ignored for now, as only NFSv3 is supported,
   *     but is included to allow future support for other versions.
   */
  public NfsCommitResponse(int nfsVersion) {
    super();
  }

  /** {@inheritDoc} */
  @Override
  public void unmarshalling(Xdr xdr) throws RpcException {
    super.unmarshalling(xdr);
    _fileWccData = new NfsWccData(xdr);
    if (stateIsOk()) {
      _verf = xdr.getLong();
      _log.trace("verf {}", _verf);
    }
  }

  /**
   * Returns a cookie that the client can use to determine whether the server has rebooted between a
   * call to WRITE and a subsequent call to COMMIT. This cookie must be consistent during a single
   * boot session and must be unique between instances of the NFS version 3 protocol server where
   * uncommitted data may be lost.
   */
  public long getVerf() {
    return _verf;
  }

  /** Returns weak cache consistency data for the file. */
  public NfsWccData getFileWccData() {
    return _fileWccData;
  }
}