4171 clean up spa_feature_*() interfaces
4172 implement extensible_dataset feature for use by other zpool features
Reviewed by: Max Grossman <max.grossman@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>

*** 350,360 ****
          if (err != 0)
                  return (err);
  
          /* Make sure dsobj has the correct object type. */
          dmu_object_info_from_db(dbuf, &doi);
!         if (doi.doi_type != DMU_OT_DSL_DATASET) {
                  dmu_buf_rele(dbuf, tag);
                  return (SET_ERROR(EINVAL));
          }
  
          ds = dmu_buf_get_user(dbuf);
--- 350,360 ----
          if (err != 0)
                  return (err);
  
          /* Make sure dsobj has the correct object type. */
          dmu_object_info_from_db(dbuf, &doi);
!         if (doi.doi_bonus_type != DMU_OT_DSL_DATASET) {
                  dmu_buf_rele(dbuf, tag);
                  return (SET_ERROR(EINVAL));
          }
  
          ds = dmu_buf_get_user(dbuf);
*** 2969,2974 ****
--- 2969,2982 ----
          if (error != 0)
                  return (B_FALSE);
          ret = dsl_dataset_is_before(origin, earlier);
          dsl_dataset_rele(origin, FTAG);
          return (ret);
+ }
+ 
+ 
+ void
+ dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx)
+ {
+         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
+         dmu_object_zapify(mos, ds->ds_object, DMU_OT_DSL_DATASET, tx);
  }