On Fri, 25 Oct 2013 08:55:23 -0400 Steve Dickson <SteveD@xxxxxxxxxx> wrote: > > > On 25/10/13 08:29, Jeff Layton wrote: > > 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. > True... but with v4 now being the default, the admin would really have > to change things for this to happen... > > I guess I really don't care if they can or can not turn off UDP, > I just think it makes sense for people to be able to disable > the best transport for v3 mounts... > > steved. > Ok, but then we go back to my original point. The best configuration in a v4-only environment is to prevent mountd from listening on any sockets. If you add the '-u' flag, and fix the '-n' flag, then users can do that. OTOH, adding a -u flag and getting rid of the -n flag seems pointless. Let's step back a moment... Why do you think it's better for v2/3 clients to use TCP vs. UDP for MNT traffic? I've always thought that the reverse is true since these sockets are almost always very short-lived. -- 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
