I eagerly await this work stabilizing to the point of merging to mainline. I'm impressed with how much progress Kent has made, but I'm frustrated by how often he seems to say some feature is basically ready except for this bug and except for that problem. I understand great designs often come from the mind of a single inspired individual, but I hope that he's ready to accept contributions from others and that more developers see the value in helping to get this across the finish line.
But the reality is that filesystem development is hard, and there aren't that many people clamoring to work on this stuff - but that's ok. Slow and steady wins the race, in the end.
I'm a big believer in steady incremental development, and being up front about what works and what doesn't - and also making sure the core is a solid foundation for everything we want to do.
For anyone who does want to get involved - come join us! irc.oftc.net#bcache
Unfortunately, file system development is a pretty niche skill set these days, and the majority of the experts in the field are employed maintaining existing file systems (ext4, xfs, apfs, etc).
One thing I’ve been bugging Kent to do is to write documentation about the design and internal workings on bcachefs; very little about modern file system design is actually written down anywhere, and a detailed reference manual would attract more people to work in this area.
