We last talked about Tux3 file-system in September and just this past week the project's Daniel Phillips has shared a progress report. Up until recently, work on the Tux3 file-system was done as a Linux FUSE module, but work is well underway in a kernel port for Tux3. For those unfamiliar with this promised file-system, it's a successor to the never-released Tux2 is a write-anywhere, atomic commit, btree-based versioning file-system.
The kernel port of Tux3 was just started by a lone developer two weeks ago and it's nearly working -- it can read files and list files but not yet write anything. A git repository is now available that holds the patches for adding Tux3 support to the Linux kernel. Daniel has also shared other thoughts on the Tux3 file-system and its design in this Linux kernel mailing list message. More information on Tux3 is available from the project's web-site.