New in this version:
- Log faulting code locations when verifiers fail, for improved diagnosis
  of corrupt filesystems.
- Implement metadata verifiers for local format inode fork data.
- Online scrub now cross-references metadata records with other metadata.
- Refactor the fs geometry ioctl generation functions.
- Harden various metadata verifiers.
- Fix various accounting problems.
- Fix uncancelled transactions leaking when xattr functions fail.
- Prevent the copy-on-write speculative preallocation garbage collector
  from racing with writeback.
- Emit log reservation type information as trace data so that we can
  compare against xfsprogs.
- Fix some erroneous asserts in the online scrub code.
- Clean up the transaction reservation calculations.
- Fix various minor bugs in online scrub.
- Log complaints about mixed dio/buffered writes once per day and less
  noisily than before.