cross-posted from: https://lemmy.ml/post/1553943

Hi,

there are mainly core changes, refactoring and optimizations. Performance is improved in some areas, overall there may be a cumulative improvement due to refactoring that removed lookups in the IO path or simplified IO submission tracking.

No merge conflicts. Please pull, thanks.

Core:

  • submit IO synchronously for fast checksums (crc32c and xxhash), remove high priority worker kthread

  • read extent buffer in one go, simplify IO tracking, bio submission and locking

  • remove additional tracking of redirtied extent buffers, originally added for zoned mode but actually not needed

  • track ordered extent pointer in bio to avoid rbtree lookups during IO

  • scrub, use recovered data stripes as cache to avoid unnecessary read

  • in zoned mode, optimize logical to physical mappings of extents

  • remove PageError handling, not set by VFS nor writeback

  • cleanups, refactoring, better structure packing

  • lots of error handling improvements

  • more assertions, lockdep annotations

  • print assertion failure with the exact line where it happens

  • tracepoint updates

  • more debugging prints

Performance:

  • speedup in fsync(), better tracking of inode logged status can avoid transaction commit

  • IO path structures track logical offsets in data structures and does not need to look it up

User visible changes:

  • don’t commit transaction for every created subvolume, this can reduce time when many subvolumes are created in a batch

  • print affected files when relocation fails

  • trigger orphan file cleanup during START_SYNC ioctl

Notable fixes:

  • fix crash when disabling quota and relocation

  • fix crashes when removing roots from drity list

  • fix transacion abort during relocation when converting from newer profiles not covered by fallback

  • in zoned mode, stop reclaiming block groups if filesystem becomes read-only

  • fix rare race condition in tree mod log rewind that can miss some btree node slots

  • with enabled fsverity, drop up-to-date page bit in case the verification fails

  • datendefekt
    3·
    2 years ago

    Is there any chance that the write hole issue with RAID5/6 will ever get fixed?

      • AtemuOP
        1·
        2 years ago

        While I’d still not recommend RAID5/6, it should be noted that that comment is now 3 years old and a lot has happened since.

    • AtemuOP
      2·
      2 years ago

      There’s work on alternative RAID5/6 modes but their performance sucks because they need to do read-modify-write.

      Note that the write hole is one of the least concerning issues with btrfs RAID5/6. It’s unstable and you shouldn’t use it for anything other than testing.

    • delial@lemmy.sdf.org
      1·
      2 years ago

      At this point, bcachefs will be merged with zraid-like features before btrfs has raid working. Truly disappointing. It feels like btrfs is great, but its design is just not suitable for raids.