static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,

                             int nb_sectors, int dirty)

{

    int64_t start, end;



    start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK;

    end = (sector_num + nb_sectors) / BDRV_SECTORS_PER_DIRTY_CHUNK;



    for (; start <= end; start++) {

        bs->dirty_bitmap[start] = dirty;

    }

}
