Bcachefs Making Tiny Steps Toward Full Self-Healing Capabilities

Another round of Bcachefs file-system fixes were merged today for the in-development Linux 6.10 kernel.

Bcachefs lead developer Kent Overstreet noted this week's work is a lot of "mostly boring" fixes. There is though a user-reported bug fix after forgetting to correctly set the bucket data type. Perhaps most exciting with this pull request is Overstreet's message that they are beginning to fix simple errors without requiring user intervention. It's an admittedly small step toward full self-healing capabilities for the Bcachefs file-system that are ultimately envisioned.

Overstreet wrote with today's Bcachefs fixes merge to Linux 6.10:

"Lots of (mostly boring) fixes for syzbot bugs and rare(r) CI bugs.

The LRU_TIME_BITS fix was slightly more involved; we only have 48 bits for the LRU position (we would prefer 64), so wraparound is possible for the cached data LRUs on a filesystem that has done sufficient (petabytes) reads; this is now handled.

One notable user reported bugfix, where we were forgetting to correctly set the bucket data type, which should have been BCH_DATA_need_gc_gens instead of BCH_DATA_free; this was causing us to go emergency read-only on a filesystem that had seen heavy enough use to see bucket gen wraparoud.

We're now starting to fix simple (safe) errors without requiring user intervention - i.e. a small incremental step towards full self healing.

This is currently limited to just certain allocation information counters, and the error is still logged in the superblock; see that patch for more information. ("bcachefs: Fix safe errors by default")"

These fixes are now in Git ahead of tomorrow's Linux 6.10-rc5 release.