Upgrade to Fedora 30 consistently corrupts bcache storage - is there some kind of emergency brake possible during upgrade?

Hi All,

There's this issue: <a href="" title=""></a>

Would have been better if I discovered it during Alpha or Beta, but
unfortunately I didn't. Now we have the situation that any bcache user
upgrading to Fedora30 involuntarily currupts his storage.

I tried to limit the impact by using a %pretrans script in bcache-tools:

_bcache=`find /sys/block/ -maxdepth 1 -name "bcache[0-9]*" | wc -l`
[[ $_bcache -gt 0 ]] || exit 0
cat >&2 << EOF
bcache will likely corrupt Fedora 30 systems beyond repare.
<a href="" title=""></a>
exit 1

But this only blocks upgrading/installing bcache-tools. The rest
(including the kernel) is still upgraded so after a reboot the storage
will get corrupted anyway. Of course adding this to the kernel package
would do the trick, but I'm not sure if that is an option.

Any suggestions on how to save people from running into this are very