DN_BONUS
vim_phys = (vdev_indirect_mapping_phys_t *)DN_BONUS(vim->vim_dn);
size = *(uint64_t *)DN_BONUS(&dir);
sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
*(uint64_t *)DN_BONUS(dnode) = nvlist_size(poolconfig);
dir->phys = (dsl_dir_phys_t *)DN_BONUS(dnode);
ds->phys = (dsl_dataset_phys_t *)DN_BONUS(dnode);
sahdr = (sa_hdr_phys_t *)DN_BONUS(dnode);
sm = DN_BONUS(sma[i].dnode);