PostgreSQL is not a filesystem. If it was pretending to be one, it would
accomplish what it does by "meta-data" undo, where the meta data of the
higher level filesystem was native to PostgreSQL (i.e. stored in table
rows), as opposed to the completely separate and irrelevant meta data of
the lower level filesystem PostgreSQL was running on top of.
So of course you can implement meta data undo on any filesystem you please,
just as long as the meta data you are referring to is not the meta data of
the filesystem itself.