130 	s->count = 0;  in init_ro_spine()
139 	for (i = 0; i < s->count; i++) {  in exit_ro_spine()
150 	if (s->count == 2) {  in ro_step()
153 		s->count--;  in ro_step()
156 	r = bn_read_lock(s->info, new_child, s->nodes + s->count);  in ro_step()
158 		s->count++;  in ro_step()
165 	BUG_ON(!s->count);  in ro_pop()
166 	--s->count;  in ro_pop()
167 	unlock_block(s->info, s->nodes[s->count]);  in ro_pop()
174 	BUG_ON(!s->count);  in ro_node()
175 	block = s->nodes[s->count - 1];  in ro_node()
185 	s->count = 0;  in init_shadow_spine()
192 	for (i = 0; i < s->count; i++) {  in exit_shadow_spine()
204 	if (s->count == 2) {  in shadow_step()
207 		s->count--;  in shadow_step()
210 	r = bn_shadow(s->info, b, vt, s->nodes + s->count);  in shadow_step()
212 		if (!s->count)  in shadow_step()
215 		s->count++;  in shadow_step()
223 	BUG_ON(!s->count);  in shadow_current()
225 	return s->nodes[s->count - 1];  in shadow_current()
230 	BUG_ON(s->count != 2);  in shadow_parent()
232 	return s->count == 2 ? s->nodes[0] : NULL;  in shadow_parent()
237 	return s->count >= 2;  in shadow_has_parent()