/ must be on a partition or LV that will be formatted. Reusing an existing / is not allowed.

[Chris Lumens]

> > > in the kickstart file? Or is this blocked as well?
> > 
> > That's going to be blocked as well, since you're doing the same thing as
> > interactive but through kickstart.

Looking at the patch, this appears to only affect interactive installs -
not kickstart.

> So does anaconda expose the full set of mkfs options, since you are now
> artificially restricting running mkfs in %pre?

There's nothing arbitrary about this.  We got no end of bugs from people
trying to do an install over top of an existing install, perhaps one
that was successful, and perhaps one that was only halfway done.  We
need to be able to start from a known state, and a preexisting / is not
it.

- Chris