nuttx/fs/fs_fsync.c

/****************************************************************************
 * fs/fs_fsync.c
 *
 *   Copyright (C) 2007-2009, 2013 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <assert.h>

#include <nuttx/fs/fs.h>
#include <nuttx/sched.h>

#include "fs_internal.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Public Variables
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: fsync
 *
 * Description:
 *   This func simply binds inode sync methods to the sync system call.
 *
 ****************************************************************************/

int fsync(int fd)
{
  FAR struct filelist *list;
  FAR struct file     *filep;
  struct inode        *inode;
  int                  ret;

  /* Get the thread-specific file list */

  list = sched_getfiles();
  DEBUGASSERT(list);

  /* Did we get a valid file descriptor? */

  if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
    {
      ret = EBADF;
      goto errout;
    }

  /* Was this file opened for write access? */

  filep = &list->fl_files[fd];
  if ((filep->f_oflags & O_WROK) == 0)
    {
      ret = EBADF;
      goto errout;
    }

  /* Is this inode a registered mountpoint? Does it support the
   * sync operations may be relevant to device drivers but only
   * the mountpoint operations vtable contains a sync method.
   */

  inode = filep->f_inode;
  if (!inode || !INODE_IS_MOUNTPT(inode) ||
      !inode->u.i_mops || !inode->u.i_mops->sync)
    {
      ret = EINVAL;
      goto errout;
    }

  /* Yes, then tell the mountpoint to sync this file */

  ret = inode->u.i_mops->sync(filep);
  if (ret >= 0)
    {
      return OK;
    }

  ret = -ret;

errout:
  set_errno(ret);
  return ERROR;
}