On Tue, 7 Dec 2010 14:31:25 -0600 Steve French <smfrench@xxxxxxxxx> wrote: > On Tue, Dec 7, 2010 at 1:10 PM, Jeff Layton <jlayton@xxxxxxxxx> wrote: > > On Tue, 7 Dec 2010 10:21:11 -0600 > > Steve French <smfrench@xxxxxxxxx> wrote: > > > >> The issue of how to prevent a page from being modified as it is > >> written out (due to signing in our case) has been discussed on lkml a > >> few times (e.g. T10 block devices). We should hold off on changing > >> this until we have a way of handling the case of: we calculate the > >> signature, but just before the page in the cache is remodified, we > >> send it with the wrong signature ... obviously if we reissue the write > >> we are fine (the data is fine) but there may be better ways to lock > >> the page (and some suggestions have been made on lkml for similar > >> sounding problems). > >> > > > > This behavior has been "Experimental" for years. At what point do we > > remove this kludge? Who in their right mind is going to turn on a > > switch called "Experimental" to enable this? As a user, I'd certainly > > be reticent to do so. It's not clear what turning on "Experimental" > > would give me. > > 20%+ better write performance > > > If you think this behavior deserves to be switchable then let's put a > > real usable switch on it. I don't think it ought to be hidden > > as /proc/fs/cifs/Experimental. Perhaps a module parameter for > > this would be more appropriate? > > Probably best to work through how to fix the general issue on fsevel > (ie how to write a presumably unstable page from the cache out) > > > Obviously there needs to be some sort of endgame for this code. It's not healthy to keep this under "Experimental" for years on end. That said, I don't really want to tackle that project at the moment. I am however interested in moving this code out from under this "Experimental" procfile. Would you be amenable to a module option for this? If so, how would you describe this knob? What name should it have? The main reason I mention module option is that it's now very helpful to have this sort of knob based on a file under /proc/fs/cifs. It can't be set at boot time without a special script. -- Jeff Layton <jlayton@xxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
