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. > >> >>> >>>>> >>>>> ...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. >>> > > -- 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
