On Fri, Mar 23, 2018 at 06:37:51PM -0400, Chuck Lever wrote: > > > > On Mar 23, 2018, at 5:55 PM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: > > > > > > > >> On Mar 23, 2018, at 5:32 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: > >> > >> If I understand correctly, in the v4 case you change the way the page > >> data is passed by using rq_arg.pages instead of a list of pages for each > >> write. > >> > >> I don't think that handles the case of compounds with multiple writes. > >> > >> If all the writes are contained in a page, then you may be OK, since the > >> wr_head iovec is all the information you need to pass the write data > >> from the xdr code to the proc code. > >> > >> But if there are multiple larger writes, you also need to know where the > >> page data is. You're depending on rq_arg.pages for that, but there's > >> only one of those per compound. > > > > I thought we were going to handle that case by chaining xdr_bufs-- > > one per NFSv4 WRITE operation. There has to be some structured way > > to pass distinct write payloads up to the NFS server, otherwise > > direct placement is impossible. > > Thinking on this a little more, I think you are saying the new shared > decoder is adequate for NFSv2 and NFSv3, but not for NFSv4. Yes, it would be a regression in the v4 case, but not in the v2 or v3 cases. > Would you > accept a patch that kept the NFSv2 and NFSv3 parts of this patch, but > dropped the NFSv4-related hunks? > > Likewise for the symlink decoder patch? I'll have to take another look, but, could be. > And we can still use a transport call-out in the XDR decoders, just as > we have discussed. (I think I've misremembered our discussion about > chaining xdr_bufs). Maybe chaining xdr bufs would make sense, I haven't thought about it. But we currently handle multiple IOs per compound without chaining xdr bufs. --b. -- 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
