(I might have just sent an empty reply to this - sorry 'bout that). On Sat, 28 Aug 2010 07:35:14 -0400 Jeff Layton <jlayton@xxxxxxxxxx> wrote: > There's a bit of a chicken and egg problem when nfsd is run the first > time. On Fedora/RHEL at least, /proc/fs/nfsd is mounted up whenever nfsd > is plugged in via a modprobe.conf "install" directive. > > If someone runs rpc.nfsd without plugging in nfsd.ko first, > /proc/fs/nfsd won't be mounted and rpc.nfsd will end up using the legacy > nfsctl interface. After that, nfsd will be plugged in and subsequent > rpc.nfsd invocations will use that instead. > > This is a problem as some nfsd command-line options are ignored when the > legacy interface is used. It'll also be a problem for people who want > IPv6 enabled servers. The upshot is that we really don't want to use the > legacy interface unless there is no other option. > > To avoid this situation, have rpc.nfsd check to see if the "threads" > file is already present. If it's not, then make an attempt to mount > /proc/fs/nfsd. This is a "best-effort" sort of thing, however so we > just ignore the return code from the mount attempt and fall back to > using nfsctl() if it fails. > > Full disclosure: I'm not 100% thrilled with this patch. It seems ugly > and kludgey, but I don't see a better way to handle this problem. > Suggestions welcome. I don't think it is all that bad. It is a shame you have to use system() rather than just calling mount() directly but I guess we need that to update /etc/mtab. Suggestions: - just don't do that. Use /etc/init.d/nfsserver start (or whatever the distro uses). - Make /proc/fs/nfsd and auto-mount point. That sounds like the systemd approach. - Print a warning message if the kernel is newer than 2.6 and nfsd-fs isn't mounted - see "don't do that" above. - If nfsdfs isn't mounted, try a no-op via the nfsd syscall, like NFSCTL_GETFD with invalid parameters. This will trigger a mod-probe which will trigger the mount. Then check for the mounted filesystem again. Yes, I think I like that one the best. NeilBrown -- 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
