On 11/30/2009 11:43 AM, Chuck Lever wrote: > On Nov 30, 2009, at 8:11 AM, Steve Dickson wrote: >> Sorry for the delayed response, I took some time off... >> >> On 11/24/2009 09:29 AM, Steve Dickson wrote: >>> >>> >>> On 11/23/2009 06:32 PM, Neil Brown wrote: >>>> >>>> Hi, >>>> I recently packaged nfs-utils 1.2.1 for openSUSE and fairly quickly >>>> got a bug report - "-o nfsvers=3" was needed to mount NFSv3 >>>> filesystems. >>>> >>>> mount.nfs in 1.2.1 will first try a v4 mount but will fall-back to v3 >>>> if it gets ENOENT. This works fine. >>>> However for kernel prior to 2.6.25, you don't get ENOENT, you get >>>> EPERM. >>>> In that case the fall-back to v3 doesn't happen and you get a failure >>>> to mount. >>>> >>>> So I think we need to fall back on EPERM as well. See below. >>> I already posted this patch on the v4 mailing list >>> http://linux-nfs.org/pipermail/nfsv4/2009-November/011595.html >>> but it got shot down... at least that's how I interpreted the >>> responses... >>> >>> But I do thing we need this, since there are so many server >>> that will simple break if we don't... Agreed? >> >> There appears to be a consensus that we need to do something >> but no agreement on what.... >> >> I believe the options are: >> 1) Start servers with '-N 4' when there is no root configured. >> * The problem I see with this is, in the event v4 support is wanted >> its yet another configuration knob that has to be turned, >> basically >> making it more difficult for people use v4. >> >> 2) Change the kernel to return NFS4ERR_SERVERFAULT when there is no >> root configured. >> * I see this is yet another errno the mounting code has to deal >> with.. >> We are up to two errnos, do we really want to add a third? >> >> Neither one of these solutions deal with legacy servers or move >> the "v4 technology" forward... IMHO... > > To quote Yoda, "No. There is another." > > Distributions can choose to revert the recently added behavior which > makes mount.nfs try vers=4 by default. That's what the mount config > file is for, yes? That seems like a responsible choice, given the > number of legacy servers still in the field. Yes... That was the main reason for the configuration file. > > At some later point (say, when your pseudoroot work is more widely > deployed), distributions can make vers=4 the default as shipped simply > by flipping a switch in the mount config file. For now, the default > behavior stays the same, with an option for individual sites to try > something new. In my opinion, default behavior out of the shrinkwrap > should always be the behavior most likely to work in any environment -- > principle of least surprise, and all that sort of thing. Not matter how or when we flip the switch, we'll have to deal with the legacy servers... > > This seems like the way we normally deploy new features like this, and > would give the many very recent changes in mount.nfs more soak time with > early adopters before we force them on everyone. Take a look at the Fedora 12... Its set up exactly as you just described with only difference vers=3 is set in the configuration file... So in my opinion, we are at the point of no return.... ;-) 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
