smb_vop_ioctl
err = smb_vop_ioctl(node->vp, _FIO_SEEK_DATA, datap, cr);
err = smb_vop_ioctl(node->vp, _FIO_SEEK_HOLE, holep, cr);
int smb_vop_ioctl(vnode_t *, int, void *, cred_t *);