I think of ZFS as a direct descendant of the 4.4BSD LFS, though I don't know that it is so -- in fact, I suspect Bonwick et. al. did not take inspiration from 4.4BSD LFS, but came up with a filesystem that looks inspired by it.
WAFL  from NetApp was/is widely in use, utilising CoW, and possibly older than this paper (wasn't able to verify but I know its from '90s at least).
This paper might've been interesting for the legal dispute between Sun and NetApp. Got settled with Oracle in 2010 though.
WAFL came a few years later - in development in the early '90s, reached production in 1994.