text: /**
   * 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.
   */
  
  #include "fuse_dfs.h"
  #include "fuse_impls.h"
  #include "fuse_file_handle.h"
  
  /**
   * This mutex is to protect releasing a file handle in case the user calls close in different threads
   * and fuse passes these calls to here.
   */
  pthread_mutex_t release_mutex = PTHREAD_MUTEX_INITIALIZER;
  
  int dfs_release (const char *path, struct fuse_file_info *fi) {
    TRACE1("release", path)
  
    // retrieve dfs specific data
    dfs_context *dfs = (dfs_context*)fuse_get_context()->private_data;
  
    // check params and the context var
    assert(path);
    assert(dfs);
    assert('/' == *path);
  
    int ret = 0;
  
    //
    // Critical section - protect from multiple close calls in different threads.
    // (no returns until end)
    //
  
    pthread_mutex_lock(&release_mutex);
  
    if (NULL != (void*)fi->fh) {
  
      dfs_fh *fh = (dfs_fh*)fi->fh;
      assert(fh);
  
      hdfsFile file_handle = (hdfsFile)fh->hdfsFH;
  
      if (NULL != file_handle) {
        if (hdfsCloseFile(fh->fs, file_handle) != 0) {
          ERROR("Could not close handle %ld for %s\n",(long)file_handle, path);
          ret = -EIO;
        }
      }
  
      if (fh->buf != NULL) {
        free(fh->buf);
      }
      // this is always created and initialized, so always destroy it. (see dfs_open)
      pthread_mutex_destroy(&fh->mutex);
  
      free(fh);
  
      fi->fh = (uint64_t)0;
    }
  
    pthread_mutex_unlock(&release_mutex);
  
    //
    // End critical section 
    // 
  
    return ret;
  }
  