Former Googler Kent Overstreet has announced that a long-term project to craft a new Linux file system is at a point where he'd like other developers to pitch in.
Since you're already asking why bother with a new file system, the answer Overstreet provides in this post to the kernel mailing list is that he wants to “match ext4 and xfs on performance and reliability, but with the features of btrfs/zfs”.
He says “the bcache codebase has been evolving/metastasizing into a full blown, general purpose posix filesystem – a modern COW [copy-on-write – El Reg] filesystem with checksumming, compression, multiple devices, caching, and eventually snapshots and all kinds of other nifty features”.
Regarding key features of the filesystem, Overstreet says multiple device support is “80 per cent” complete with the recovery code to be completed; caching and tiering are functional, at least; compression currently uses zlib only, and there's a choice between crc32c or a 64 bit checksum.
“My main priority is getting the code sufficiently stable and tested for production use, probably the #2 priority is snapshots. Bcachefs won't be done in a month (or a year), but I do want to see it out there and getting used”, he writes.
Regarding the need for other contributors. Overstreet remarks that he's been working on it as a full-time project while living on savings, so “this would be a wonderful time both for other developers to jump in and get involved, and for potential users to pony up some funding”.