On Sat, Jan 03, 2015 at 05:40:24PM +0100, Rolf Fokkens wrote:

Hi Slava,

Sounds like the kernel (using bcache-dev) is not able to handle the current
format. If so, bcache-tools may help in "reformatting" bcache devices, but
that's no solution for existing systems.

So is my understanding correct that there's no easy kernel upgrade path (to
bcache-dev) ?

Yes, correct. The on disk format changes in bcache-dev are just too deep to
feasibly write backwards compat code, unfortunately.

And the on disk format is still in flux - for just a bit longer hopefully
though, right now I'm working on a pretty major revamp that's getting close to
done (self describing and packed metadata). This revamp is making the on disk
format _much_ more flexible though, and cleaning up a lot of stuff at the same
time.