const char *scope, const void *source);
struct cl_lock *cl_lock_at_page(const struct lu_env *env, struct cl_object *obj,
struct cl_page *page, struct cl_lock *except,
const char *scope, const void *source);
struct cl_lock *cl_lock_at_page(const struct lu_env *env, struct cl_object *obj,
struct cl_page *page, struct cl_lock *except,