zvol_volsize_to_reservation
volsize = zvol_volsize_to_reservation(zpool_handle, volsize,
extern uint64_t zvol_volsize_to_reservation(zpool_handle_t *, uint64_t,
if ((zvol_volsize_to_reservation(zph, old_volsize, props) !=
new_reservation = zvol_volsize_to_reservation(zph, new_volsize, props);
resvsize = zvol_volsize_to_reservation(zpool_handle(zhp), volsize,