int traverse_dataset(struct dsl_dataset *ds,
uint64_t txg_start, int flags, blkptr_cb_t func, void *arg);
int traverse_pool(spa_t *spa,
int traverse_dataset(struct dsl_dataset *ds,
uint64_t txg_start, int flags, blkptr_cb_t func, void *arg);
int traverse_pool(spa_t *spa,