Messages in this thread | | | From | "Myklebust, Trond" <> | Subject | Re: [PATCH 2/2] NFSv4: Return the delegation if the server returns NFS4ERR_OPENMODE | Date | Thu, 8 Mar 2012 20:50:14 +0000 |
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On Thu, 2012-03-08 at 15:42 -0500, J. Bruce Fields wrote: > On Thu, Mar 08, 2012 at 03:23:34PM -0500, Olga Kornievskaia wrote: > > On Thu, Mar 8, 2012 at 1:15 PM, Myklebust, Trond > > <Trond.Myklebust@netapp.com> wrote: > > > On Thu, 2012-03-08 at 12:52 -0500, Olga Kornievskaia wrote: > > >> wouldn't it be better for you to proactively return a read delegation > > >> then unnecessarily erroring? > > > > > > If nobody else holds a delegation, then the NFS client is actually > > > allowed to keep its read delegation while writing to the file. It does > > > admittedly need to request an OPEN stateid for write in that case... > > > (See section 10.4 of RFC3530bis draft 16) > > > > If we both agree that there has to be a request for an open stateid for > > a write, then instead of returning the read delegation if the client receives > > err_openmode (when it send the request with read delegation stateid > > as you said per 3560bis), can't the client resend the setattr with the open > > stateid? The ordering of the stateid usage is a "should" and not a "must". > > > > In rfc5661, it really doesn't make sense to ever send a setattr with > > a read delegation stateid. According to 9.1.2, the server "MUST" return > > err_open_mode" error in that case. > > > > I gather you are in this case dealing with 4.0 delegations. But I wonder > > if you'll do something else for 4.1 delegation then? > > 3530bis has the same language ("...must verify that the access mode > allows writing and return an NFS4ERR_OPENMODE error if it does not").
OK, so we shouldn't send the delegation stateid either for v4 or v4.1. However should we pre-emptively return the delegation? I've been assuming not.
-- Trond Myklebust Linux NFS client maintainer
NetApp Trond.Myklebust@netapp.com www.netapp.com
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