On 25/10/13 09:03, Jeff Layton wrote: > 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. This these patches have nothing to do with v4 mounts... The are all about limiting people to use the TCP mounts for v2/v3 mounts... > > 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. Obviously UDP... but the code will try TCP if UDP does not exists... Again, with v4 being the default, people would really have work hard to put themselves in this position... steved. > -- 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
