Comment # 6 on bug 1172273 from Ignaz Forster

(In reply to Fabian Vogt from comment #5)
> (In reply to Thorsten Kukuk from comment #4)
> > As Ignaz wrote: we can assume that a system is using transactional-updates,
> > if the root filesystem is read-only.
> > 
> > So, if the root filesystem is read-only and snapper rollback is called,
> 
> This also matches the case when booting into a read-only snapshot on plain
> TW,
> so it would need some additional criteria.

That's why I suggested to check whether the *default* root file system snapshot
is read-only in my last comment already :-)