33     BlockDriverState *bottom_bs;  member
41     BlockDriverState *bottom_bs = NULL;  in cor_open()  local
66         bottom_bs = bdrv_find_node(bottom_node);  in cor_open()
67         if (!bottom_bs) {  in cor_open()
74         if (!bottom_bs->drv) {  in cor_open()
79         if (bottom_bs->drv->is_filter) {  in cor_open()
84         if (bdrv_freeze_backing_chain(bs, bottom_bs, errp) < 0) {  in cor_open()
93         bdrv_ref(bottom_bs);  in cor_open()
95     state->bottom_bs = bottom_bs;  in cor_open()
144     if (!state->bottom_bs) {  in cor_co_preadv_part()
156                                              state->bottom_bs, true, offset,  in cor_co_preadv_part()
243         bdrv_unfreeze_backing_chain(bs, s->bottom_bs);  in cor_close()
247     bdrv_unref(s->bottom_bs);  in cor_close()
284         bdrv_unfreeze_backing_chain(cor_filter_bs, s->bottom_bs);  in bdrv_cor_filter_drop()