zpool import speedup

@@ -163,11 +163,13 @@
 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