Bcachefs Prepares Last Minute Fixes For Linux 6.7

Ahead of Linux 6.7 releasing next weekend, there's another set of Bcachefs file-system driver fixes on their way to the mainline kernel.

Merging of Bcachefs is one of the many exciting Linux 6.7 features for this copy-on-write file-system that's been in development for years and born out of the kernel's block cache code. Since making it into the kernel at long last during the v6.7 merge window, there's been a few round of fixes for getting this still-experimental file-system into better shape ahead of the v6.7 stable release.

On New Year's day Bcachefs lead developer Kent Overstreet sent out a batch of "new year fixes" that are awaiting to be merged by Linus Torvalds. This newest round of fixes has some compatibility work so that Linux 6.7 will be able to handle an ongoing disk space accounting rewrite, fix for "a nasty extents + snapshot interaction" issue, a fix for a buffer overflow in the no CoW write path, read-only snapshots are now actually read-only, and a handful of other fixes.

"- fix for a nasty extents + snapshot interaction, reported when reflink of a snapshotted file wouldn't complete but turned out to be a more general bug
- fix for an invalid free in dio write path when iov vector was longer than our inline vector
- fix for a buffer overflow in the nocow write path - BCH_REPLICAS_MAX doesn't actually limit the number of pointers in an extent when cached pointers are included
- RO snapshots are actually RO now
- And, a new superblock section to avoid future breakage when the disk space accounting rewrite rolls out: the new superblock section describes versions that need work to downgrade, where the work required is a list of recovery passes and errors to silently fix."

Assuming Linus Torvalds doesn't raise any objections, these Bcachefs fixes should be mainlined later today or so.