zpool import speedup

*** 163,173 ****
--- 163,175 ----
  int dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj,
      const char *tag, dmu_tx_t *tx);
  void dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp);
  int dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **);
  int dsl_pool_hold(const char *name, void *tag, dsl_pool_t **dp);
+ int dsl_pool_hold_lock(const char *name, void *tag, dsl_pool_t **dp, int lock);
  void dsl_pool_rele(dsl_pool_t *dp, void *tag);
+ void dsl_pool_rele_spa(dsl_pool_t *dp, void *tag);
  
  #ifdef  __cplusplus
  }
  #endif