Function my_b_flush_io_cache

mysys/mf_iocache.c:1734–1817

  unlock_append_buffer(info);

int my_b_flush_io_cache(IO_CACHE *info,
                        int need_append_buffer_lock __attribute__((unused)))
{
  size_t length;
  my_off_t pos_in_file;
  my_bool append_cache= (info->type == SEQ_READ_APPEND);
  DBUG_ENTER("my_b_flush_io_cache");
  DBUG_PRINT("enter", ("cache: 0x%lx", (long) info));

  if (!append_cache)
    need_append_buffer_lock= 0;

  if (info->type == WRITE_CACHE || append_cache)
  {
    if (info->file == -1)
    {
      if (real_open_cached_file(info))
	DBUG_RETURN((info->error= -1));
    }
    LOCK_APPEND_BUFFER;

    if ((length=(size_t) (info->write_pos - info->write_buffer)))
    {
      /*
        In case of a shared I/O cache with a writer we do direct write
        cache to read cache copy. Do it before the write here so that
        the readers can work in parallel with the write.
        copy_to_read_buffer() relies on info->pos_in_file.
      */
      if (info->share)
        copy_to_read_buffer(info, info->write_buffer, length);

      pos_in_file=info->pos_in_file;
      /*
	If we have append cache, we always open the file with
	O_APPEND which moves the pos to EOF automatically on every write
      */
      if (!append_cache && info->seek_not_done)
      {					/* File touched, do seek */
	if (mysql_file_seek(info->file, pos_in_file, MY_SEEK_SET, MYF(0)) ==
	    MY_FILEPOS_ERROR)
	{
	  UNLOCK_APPEND_BUFFER;
	  DBUG_RETURN((info->error= -1));
	}
	if (!append_cache)
	  info->seek_not_done=0;
      }
      if (!append_cache)
	info->pos_in_file+=length;
      info->write_end= (info->write_buffer+info->buffer_length-
			((pos_in_file+length) & (IO_SIZE-1)));

      if (mysql_file_write(info->file,info->write_buffer,length,
		   info->myflags | MY_NABP))
	info->error= -1;
      else
	info->error= 0;