J. Bruce Fields wrote: > On Wed, Oct 29, 2008 at 04:30:32PM -0400, Chuck Lever wrote: >> I assume sync() is required because this logic performs a rename as well >> as a simple write? > > I think an fsync() on the containing directory (together with an fsync() > of the file itself) would do the job if you wanted to avoid the globaly > sync(). I don't think ext3 is capable of doing anything finer-grained > than a whole-filesystem sync, though, so this doesn't help many people > in practice right now. > > In any case, the rename adds an extra level of safety by ensuring the > nsm state is updated atomically, so we shouldn't get rid of it. > >>> Anyway, I think the nsm state updating shouldn't matter if you don't >>> even have any peers to notify. >> It probably does matter. >> >> When a system is initially installed, it likely does not have a state >> file in /var/lib/nfs. This may be harmless if it's not present; >> rpc.statd probably does the right thing in this case. > > The "right thing" in that case would be, I guess, to create a state file > with "0" in it. It doesn't do that. So this patch *does* break stuff. > Oops! > > So should we revert it and do something else, or patch statd to create > a new state file if necessary? I have to agree with Chuck, that managing the state file from one place is desirable... Although does it make sense to move that management into a init script? Maybe insuring the state is different before any daemons are started? Would we still need the sync()? > >> However, the rest of the logic in nsm_get_state() is needed to bump the >> system's state value properly after every reboot. It may be >> inconsequential if there were no mounts or no NFS clients during the >> last reboot, but this is subtle. I wouldn't bet on it. > > If the state is only every communicated to hosts by notifications, then > if we're not notifying, the update of the state can't matter. I had the same notion... If there are no clients to notify, why would any clients care if our state changed?? With that said.... I do have a sinking feeling that this patch will come back to bite us... It was just too easy of a fix... :-) 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
