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>

*** 25,34 ****
--- 25,35 ----
  
  #ifndef _SYS_ZFEATURE_H
  #define _SYS_ZFEATURE_H
  
  #include <sys/nvpair.h>
+ #include <sys/txg.h>
  #include "zfeature_common.h"
  
  #ifdef  __cplusplus
  extern "C" {
  #endif
*** 35,56 ****
  
  struct spa;
  struct dmu_tx;
  struct objset;
  
- extern boolean_t feature_is_supported(struct objset *os, uint64_t obj,
-     uint64_t desc_obj, nvlist_t *unsup_feat, nvlist_t *enabled_feat);
- 
  extern void spa_feature_create_zap_objects(struct spa *, struct dmu_tx *);
! extern void spa_feature_enable(struct spa *, zfeature_info_t *,
      struct dmu_tx *);
! extern void spa_feature_incr(struct spa *, zfeature_info_t *, struct dmu_tx *);
! extern void spa_feature_decr(struct spa *, zfeature_info_t *, struct dmu_tx *);
! extern boolean_t spa_feature_is_enabled(struct spa *, zfeature_info_t *);
! extern boolean_t spa_feature_is_active(struct spa *, zfeature_info_t *);
! extern int spa_feature_get_refcount(struct spa *, zfeature_info_t *);
  
  #ifdef  __cplusplus
  }
  #endif
  
  #endif /* _SYS_ZFEATURE_H */
--- 36,65 ----
  
  struct spa;
  struct dmu_tx;
  struct objset;
  
  extern void spa_feature_create_zap_objects(struct spa *, struct dmu_tx *);
! extern void spa_feature_enable(struct spa *, spa_feature_t,
      struct dmu_tx *);
! extern void spa_feature_incr(struct spa *, spa_feature_t, struct dmu_tx *);
! extern void spa_feature_decr(struct spa *, spa_feature_t, struct dmu_tx *);
! extern boolean_t spa_feature_is_enabled(struct spa *, spa_feature_t);
! extern boolean_t spa_feature_is_active(struct spa *, spa_feature_t);
! extern uint64_t spa_feature_refcount(spa_t *, spa_feature_t, uint64_t);
! extern boolean_t spa_features_check(spa_t *, boolean_t, nvlist_t *, nvlist_t *);
  
+ /*
+  * These functions are only exported for zhack and zdb; normal callers should
+  * use the above interfaces.
+  */
+ extern int feature_get_refcount(struct spa *, zfeature_info_t *, uint64_t *);
+ extern void feature_enable_sync(struct spa *, zfeature_info_t *,
+     struct dmu_tx *);
+ extern void feature_sync(struct spa *, zfeature_info_t *, uint64_t,
+     struct dmu_tx *);
+ 
  #ifdef  __cplusplus
  }
  #endif
  
  #endif /* _SYS_ZFEATURE_H */