vop_getextattr
.vop_getextattr = (void *)vop_eopnotsupp,
DO_OPS(ops, error, &ap, vop_getextattr);
DO_OPS(ap->a_head.a_ops, error, ap, vop_getextattr);
vop_getextattr(*(vp)->v_ops, vp, attrnamespace, attrname, uio, cred)
int (*vop_getextattr)(struct vop_getextattr_args *);
int vop_getextattr(struct vop_ops *ops, struct vnode *vp, int attrnamespace,
.vop_getextattr = smbfs_getextattr