src/contrib/fuse-dfs/src/fuse_impls_statfs.c

/**
 * 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_connect.h"


int dfs_statfs(const char *path, struct statvfs *st)
{
  TRACE1("statfs",path)

  // retrieve dfs specific data
  dfs_context *dfs = (dfs_context*)fuse_get_context()->private_data;

  // check params and the context var
  assert(path);
  assert(st);
  assert(dfs);

  // init the stat structure
  memset(st,0,sizeof(struct statvfs));

  hdfsFS userFS;
  // if not connected, try to connect and fail out if we can't.
  if ((userFS = doConnectAsUser(dfs->nn_hostname,dfs->nn_port))== NULL) {
    syslog(LOG_ERR, "ERROR: could not connect to dfs %s:%d\n", __FILE__, __LINE__);
    return -EIO;
  }

  const long cap   = hdfsGetCapacity(userFS);
  const long used  = hdfsGetUsed(userFS);
  const long bsize = hdfsGetDefaultBlockSize(userFS);

  // fill in the statvfs structure

  /* FOR REFERENCE:
     struct statvfs {
     unsigned long  f_bsize;    // file system block size
     unsigned long  f_frsize;   // fragment size
     fsblkcnt_t     f_blocks;   // size of fs in f_frsize units
     fsblkcnt_t     f_bfree;    // # free blocks
     fsblkcnt_t     f_bavail;   // # free blocks for non-root
     fsfilcnt_t     f_files;    // # inodes
     fsfilcnt_t     f_ffree;    // # free inodes
     fsfilcnt_t     f_favail;   // # free inodes for non-root
     unsigned long  f_fsid;     // file system id
     unsigned long  f_flag;     / mount flags
     unsigned long  f_namemax;  // maximum filename length
     };
  */

  st->f_bsize   =  bsize;
  st->f_frsize  =  bsize;

  st->f_blocks  =  cap/bsize;

  st->f_bfree   =  (cap-used)/bsize;
  st->f_bavail  =  (cap-used)/bsize;

  st->f_files   =  1000;
  st->f_ffree   =  500;
  st->f_favail  =  500;
  st->f_fsid    =  1023;
  st->f_flag    =  ST_RDONLY | ST_NOSUID;
  st->f_namemax =  1023;

  return 0;
}