From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Layton Subject: Re: [PATCH 09/18] nfsd: implement pNFS operations Date: Fri, 9 Jan 2015 09:28:35 -0800 Message-ID: <20150109092835.5fdbac5d@synchrony.poochiereds.net> References: <1420561721-9150-1-git-send-email-hch@lst.de> <1420561721-9150-10-git-send-email-hch@lst.de> <20150108164851.03b64e16@synchrony.poochiereds.net> <20150109100551.GA23173@lst.de> <20150109085130.0f862d24@synchrony.poochiereds.net> <20150109171641.GA17464@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-nfs@vger.kernel.org, trond.myklebust@primarydata.com, Sachin Bhamare , xfs@oss.sgi.com, "J. Bruce Fields" , linux-fsdevel@vger.kernel.org, thomas.haynes@primarydata.com, Jeff Layton To: Christoph Hellwig Return-path: In-Reply-To: <20150109171641.GA17464@lst.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com List-Id: linux-fsdevel.vger.kernel.org On Fri, 9 Jan 2015 18:16:41 +0100 Christoph Hellwig wrote: > On Fri, Jan 09, 2015 at 08:51:30AM -0800, Jeff Layton wrote: > > Ok, it'd be good to document that in some comments then for the sake of > > posterity (maybe it is later in the set -- I haven't gotten to the end > > yet). > > What kinds of comments do you expect? Not implementing unused features > of a protocol should be the default for anything in Linux. > I was thinking just a comment saying that ROC is always true in this implementation, or maybe consider eliminating the lg_roc field in struct nfsd4_layoutget altogether since it's currently always "1". It's a little confusing now since the encoder can handle the case where lg_roc is 0, but the rest of the code can't. > > Now, that said...I think that your ROC semantics are wrong here. You > > also have to take delegations into account. [1] > > > > Basically the semantics that you want are that nfsd should do all of > > the ROC stuff on last close iff there are no outstanding delegations or > > on delegreturn iff there are no opens. > > > > What we ended up doing in the unreleased code we have was to create a > > new per-client and per-file object (that we creatively called an > > "odstate"). An open stateid and a delegation stateid would hold a > > reference to this object which is put when those stateids are freed. > > When its refcount goes to zero, then we'd free any outstanding layouts > > on the file for that client and free the object. > > > > You probably want to do something similar here. > > > > [1]: Tom and Trond mentioned that there's a RFC5661 errata pending for > > this, but I don't see it right offhand. > > It would be good to look at the errata. While the idea of keeping > layouts around longer makes sense, I would only expect to do this > if they layout state was created based on a delegation stateid, not > a lock or open stateid. In that case having the layouts hang off > the "parent" stateid might be another option. I found it: http://www.rfc-editor.org/errata_search.php?rfc=5661&eid=3226 -- Jeff Layton _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs