128 	s->nodes[0] = NULL;  in init_ro_spine()
129 	s->nodes[1] = NULL;  in init_ro_spine()
137 		unlock_block(s->info, s->nodes[i]);  in exit_ro_spine()
145 		unlock_block(s->info, s->nodes[0]);  in ro_step()
146 		s->nodes[0] = s->nodes[1];  in ro_step()
150 	r = bn_read_lock(s->info, new_child, s->nodes + s->count);  in ro_step()
161 	unlock_block(s->info, s->nodes[s->count]);  in ro_pop()
169 	block = s->nodes[s->count - 1];  in ro_node()
187 		unlock_block(s->info, s->nodes[i]);  in exit_shadow_spine()
196 		unlock_block(s->info, s->nodes[0]);  in shadow_step()
197 		s->nodes[0] = s->nodes[1];  in shadow_step()
201 	r = bn_shadow(s->info, b, vt, s->nodes + s->count);  in shadow_step()
204 			s->root = dm_block_location(s->nodes[0]);  in shadow_step()
216 	return s->nodes[s->count - 1];  in shadow_current()
223 	return s->count == 2 ? s->nodes[0] : NULL;  in shadow_parent()