Bcache: Caching beyond just RAM

Interesting project. However, I wonder how this will work with something like cleancache(http://lwn.net/Articles/389873/). Cleancache works in the realm of VM. So is bcache supposed to complement cleancache or is a replacement for it.

The transparency of bcache is quite nice. Is bcache available as module(so that it can be built out of tree and used) ?