On Fri, 25 Oct 2013 08:23:29 -0400 Steve Dickson <SteveD@xxxxxxxxxx> wrote: > > > On 25/10/13 07:43, Jeff Layton wrote: > > On Thu, 24 Oct 2013 15:45:03 -0400 > > Steve Dickson <SteveD@xxxxxxxxxx> wrote: > > > >> > >> > >> On 24/10/13 14:45, Jeff Layton wrote: > >>> On Thu, 24 Oct 2013 14:17:10 -0400 > >>> Steve Dickson <steved@xxxxxxxxxx> wrote: > >>> > >>>> [ Here is the second try for these patches incorporating the code review..] > >>>> > >>>> Recently it was pointed out to me that the [-n | --no-tcp] flags > >>>> were broken in mountd. Sure enough they are and they broke > >>>> when nfs-utils moved to using libtirpc, which was years ago. > >>>> > >>>> Obviously nobody is using these flags since has not been > >>>> notice until now, but it seemed to me it no longer makes > >>>> any sense to have flags. We really want people to use TCP > >>>> so why should there be a way to turn it off? It should be > >>>> the opposite... They should be able to turn off UDP listeners > >>>> not TCP... > >>>> > >>>> > >>>> Steve Dickson (3): > >>>> mountd: Use protocol bit fields to turn protocols off. > >>>> mountd: Deprecate the ability to disable TCP listeners. > >>>> mountd: Add the ability to disable UDP listeners. > >>>> > >>>> support/include/rpcmisc.h | 2 +- > >>>> support/nfs/rpcmisc.c | 19 ++++++++++++++----- > >>>> support/nfs/svc_create.c | 5 +++++ > >>>> utils/mountd/mountd.c | 17 ++++++++++++----- > >>>> utils/mountd/mountd.man | 6 +++--- > >>>> 5 files changed, 35 insertions(+), 14 deletions(-) > >>>> > >>> > >>> Sorry I'm coming in late on this... > >> np... I was expecting more push back! ;-) > >> > >>> > >>> I don't think we want to remove the ability to disable TCP listeners. > >>> > >>> Why, you ask? We've been on a multi-year effort to move people to > >>> NFSv4, and with that, there's no reason to have mountd listen on the > >>> network at all. > >> True... > >> > >>> > >>> So personally, I think it would make sense to: > >>> > >>> a) allow people to disable listening on UDP in addition to TCP > >> I see no reason whatsoever to turn off TCP listeners especially > >> since that is the protocol of choice... something we have > >> be spouting about for years... > >> > > > > There are reasons to be able to turn off TCP listeners: > > > > If you're running a NFSv4-only server, there's no reason to allow it to > > listen on TCP _or_ UDP sockets. I think that sort of environment is > > going to become more prevalent in the future, not less. > I ideally it would be best not to have mountd at all on NFSv4-only server. > Basically, have the kernel get its exports like it gets it ID mappings. > Until that day comes, which I hope fill be soon, the TCP listener > only effects v3 mounts and we definitely want people to use TCP > with v3. > We want people to use TCP for NFS protocol with v3. In general however, we do *not* want them using TCP for the MNT protocol. We've had many problems in the past with clients hitting reserved port exhaustion due to using TCP for short-lived sockets to carry MNT traffic. This is the reason that the client defaults to UDP for MNT traffic. > > > > >>> > >>> ...or... > >>> > >>> b) add an option that prevents it from listening on any sockets for a > >>> v4-only configuration > >> In this case it would optimal to not even start mountd, unfortunately > >> due to exports reasons, it not possible... but it should be!! :-) > >> > > > > Right, mountd has 2 jobs: > > > > 1) respond to MNT protocol requests from clients > > > > ...and... > > > > 2) feed exports info to the kernel > > > > For v4, you obviously don't need the first role, so being able to > > disable network listeners is a good thing in such a configuration. > Again, I would rather build an v4 only environment where mountd > does not even run... > I'd be fine with that. But until that materializes we're stuck with running mountd in some form on the server. > > > > >>> > >>> In addition, we generally do want people to use UDP for the MNT > >>> protocol because it's less apt to cause issues with reserved port > >>> exhaustion. Given that it'll continue to listen on a UDP socket by > >>> default, that last point is less of an issue, but that might be a good > >>> reason to rethink this whole plan. > >>> > >> I did think of this.... UDP is on by default... Is up the admin... > >> > > > > That's good. I have no objection to adding an option to disable UDP > > listeners if the admin chooses. I just think it would be best to fix > > the ability to disable TCP listeners as well instead of removing it. > > -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
