unix domain sockets on nullfs(5)

[Mikolaj Golub]

On Tue, Jan 10, 2012 at 10:30 PM, Mikolaj Golub <trociny at freebsd.org> wrote:
>
> On Tue, 10 Jan 2012 14:02:34 +0000 Robert N. M. Watson wrote:
>
>  RNMW> (1) I don't think the new behaviour should be optional -- it was always
>  RNMW> the intent that nullfs pass through all behaviours to the underlying
>  RNMW> layer, it's just that certain edge cases didn't appear in the original
>  RNMW> implementation. Memory mapping was fixed a few years ago using similar
>  RNMW> techniques. This will significantly reduce the complexity of your
>  RNMW> patch, and also avoid user confusion since it will now behave "as
>  RNMW> expected". Certainly, mention in future release notes would be
>  RNMW> appropriate, however.
>
> I don't mind having only the new behavior, as I can't imagine where I would
> need a nullfs with nosobypass option mounted and I also like when things are
> simple :-).
>
> On the other hand there might be people who relied on the old behavior and who
> would be surprised if it had changed.
>
> So, if other people agree I will remove the old behaviour to make the patch
> simpler. Another option would be to have sobypass by default with possibility
> to (re)mount fs with nosobypass.
>

If we agree to have only the new behavior then nullfs won't need modification
at all, it will work as expected automatically. The patch could be (with updated
locking for the connect case):

http://people.freebsd.org/~trociny/VOP_UNP.1.patch