This intrusiveness is very bothersome. How about a different model
where the unionfs is really just a file-system that unions two others
(i.e. a total of 3 filesystems involved). This way, all the white-out
garbage can be kept in unionfs. Also the `move directory' could potentially
be dealt with by having the unionfs layer remember the move (basically,
unionfs would be a layer of redirection-pointers that originally
either point to a same-name node in fs1 or a same-name node in fs2,
and over time that would change by adding pointers to nowhereland
(white-outs) and pointers to different-name nodes in fs[12].
Of course, it might be better to make those redirection-pointers point
to several places at a time (if those places a re directories).
To provide persistence, the unionfs would of course need some disk space,
which would probably be a file rather than a partition.
Write access would either be disallowed, or would be applied to one of the
underlying filesystems. Unless we want to make unionfs a full-blown filesystem
so that you can write to it and create files directly in it.
Stefan
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/