ro_spine
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
void exit_ro_spine(struct ro_spine *s);
int ro_step(struct ro_spine *s, dm_block_t new_child);
void ro_pop(struct ro_spine *s);
struct btree_node *ro_node(struct ro_spine *s);
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
void exit_ro_spine(struct ro_spine *s)
int ro_step(struct ro_spine *s, dm_block_t new_child)
void ro_pop(struct ro_spine *s)
struct btree_node *ro_node(struct ro_spine *s)
static int find_key(struct ro_spine *s, dm_block_t block, bool find_highest,
struct ro_spine spine;
static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
struct ro_spine spine;
struct ro_spine spine;