inline int sync_filesystem(int fd)
{
  /* On Linux, newer versions of glibc have a function called syncfs that
   * performs a sync on only one filesystem. If we don't have this call, we
   * have to fall back on sync(), which synchronizes every filesystem on the
   * computer. */
#ifdef HAVE_SYS_SYNCFS
  if (syncfs(fd) == 0)
    return 0;
#elif defined(SYS_syncfs)
  if (syscall(SYS_syncfs, fd) == 0)
    return 0;
#elif defined(__NR_syncfs)
  if (syscall(__NR_syncfs, fd) == 0)
    return 0;
#endif

#ifdef BTRFS_IOC_SYNC
  if (::ioctl(fd, BTRFS_IOC_SYNC) == 0)
    return 0;
#endif

  sync();
  return 0;
}

#endif