zpool import speedup

@@ -568,10 +568,11 @@
         SPA_IMPORT_ASSEMBLE
 } spa_import_type_t;
 
 /* state manipulation functions */
 extern int spa_open(const char *pool, spa_t **, void *tag);
+extern int spa_open_lock(const char *pool, spa_t **, void *tag, int lock);
 extern int spa_open_rewind(const char *pool, spa_t **, void *tag,
     nvlist_t *policy, nvlist_t **config);
 extern int spa_get_stats(const char *pool, nvlist_t **config, char *altroot,
     size_t buflen);
 extern int spa_create(const char *pool, nvlist_t *config, nvlist_t *props,