xagb_bitmap_disunion
error = xagb_bitmap_disunion(agfl_extents, &ra.agmetablocks);
error = xagb_bitmap_disunion(agfl_extents, &ra.crossed);
error = xagb_bitmap_disunion(agfl_extents, &af.used_extents);
error = xagb_bitmap_disunion(&ra->old_allocbt_blocks,