ZPOOL_HIST_ZONE
if (nvlist_exists(rec, ZPOOL_HIST_ZONE)) {
fnvlist_lookup_string(rec, ZPOOL_HIST_ZONE));
if (nvlist_lookup_string(nvl, ZPOOL_HIST_ZONE, &string) == 0)
fnvlist_add_string(nvarg, ZPOOL_HIST_ZONE,