Please let us know when this will be pushed to the kernel, do you have 
any thoughts on the planning of this?

As a bcache-tools packager for Fedora I think I should add some package 
dependencies which prevent users from accidentally upgrading to that 
(breaking) version in the future.

It may also affect other tools like util-linux: 
https://github.com/karelzak/util-linux/blob/master/libblkid/src/superblocks/bcache.c

Furthermore I think I should postpone integration of bcache in the 
Fedora installer until further notice: 
https://bugzilla.redhat.com/show_bug.cgi?id=1003208

Any information in advance is appreciated.

Rolf

On 01/04/2015 01:46 AM, Kent Overstreet wrote:

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.