On Fri, Feb 26, 2016 at 09:37:22PM +0100, Stanislav Brabec wrote: > Do I understand, that you are saying: > > Yes, mounting multiple loop devices associated with one file is a > legitimate use, but mount(8) should never do it, because it has other > ugly side effects?
It's on the same level as "hey, let's have an nbd daemon run in qemu guest, exporting a host file over nbd, import it to host as /dev/nbd69, set a loopback device over the underlying file as /dev/loop42 and ask e.g. xfs to recognize that it's dealing with the same underlying array of bytes in both cases - wouldn't it be neat if it could do that?" There's no magic. Really. Unexpected sharing of backing store between apparently unrelated devices can cause trouble. And I'm not sure how to deal with -o loop in a sane way, TBH - automagical losetup is bloody hard to get right. Keep in mind that loop-over-loop is also possible...
