4K-sector drives and Fedora

One thing that seems to have been skipped in the discussion so far is that this is not just an issue with local, 4KB sector drives. The changes we have in the kernel and in the tool chain will help with external arrays which have long had larger internal "sectors" but pretended to have 512 byte sectors like a local disk.

The larger impact of the change is that it should all "just work" if we got all of the bits in place correctly :-)

Testing on a variety of storage hardware from various vendors, without and without DM and MD is really, really interesting right now to help us uncover any bits we did miss.