* https://www.youtube.com/watch?v=_NuhRkiInvA (BSDCan)
* https://www.mckusick.com/softdep/suj.pdf
Which also allows snapshots:
* https://freebsdfoundation.org/project/snapshots-on-filesyste...
See also "Journaling versus Soft Updates: Asynchronous Meta-data Protection in File Systems":
* https://www.seltzer.com/assets/publications/Journaling-versu...