On Mon, Jul 22, 2013 at 03:54:00PM -0400, Bryan Schumaker wrote: > On 07/22/2013 03:43 PM, J. Bruce Fields wrote: > > On Mon, Jul 22, 2013 at 03:37:00PM -0400, Bryan Schumaker wrote: > >> On 07/22/2013 03:30 PM, J. Bruce Fields wrote: > >>> On Mon, Jul 22, 2013 at 03:17:29PM -0400, Bryan Schumaker wrote: > >>>> On 07/22/2013 02:50 PM, J. Bruce Fields wrote: > >>>>> On Fri, Jul 19, 2013 at 05:03:49PM -0400, bjschuma@xxxxxxxxxx wrote: > >>>>>> From: Bryan Schumaker <bjschuma@xxxxxxxxxx> > >>>>>> > >>>>>> Rather than performing the copy right away, schedule it to run later and > >>>>>> reply to the client. Later, send a callback to notify the client that > >>>>>> the copy has finished. > >>>>> > >>>>> I believe you need to implement the referring triple support described > >>>>> in http://tools.ietf.org/html/rfc5661#section-2.10.6.3 to fix the race > >>>>> described in > >>>>> http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion2-19#section-15.1.3 > >>>>> . > >>>> > >>>> I'll re-read and re-write. > >>>> > >>>>> > >>>>> I see cb_delay initialized below, but not otherwise used. Am I missing > >>>>> anything? > >>>> > >>>> Whoops! I was using that earlier to try to fake up a callback, but I eventually decided it's easier to just do the copy asynchronously. I must have forgotten to take it out :( > >>>> > >>>>> > >>>>> What about OFFLOAD_STATUS and OFFLOAD_ABORT? > >>>> > >>>> I haven't thought out those too much... I haven't thought about a use for them on the client yet. > >>> > >>> If it might be a long-running copy, I assume the client needs the > >>> ability to abort if the caller is killed. > >>> > >>> (Dumb question: what happens on the network partition? Does the server > >>> abort the copy when it expires the client state?) > >>> > >>> In any case, > >>> http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion2-19#section-15.1.3 > >>> says "If a server's COPY operation returns a stateid, then the server > >>> MUST also support these operations: CB_OFFLOAD, OFFLOAD_ABORT, and > >>> OFFLOAD_STATUS." > >>> > >>> So even if we've no use for them on the client then we still need to > >>> implement them (and probably just write a basic pynfs test). Either > >>> that or update the spec. > >> > >> Fair enough. I'll think it out and do something! Easy solution: save this patch for later and only support the sync version of copy for the final version of this patch series. > > > > I can't remember--does the spec give the server a clear way to bail out > > and tell the client to fall back on a normal copy in cases where the > > server knows the copy could take an unreasonable amount of time? > > > > --b. > > I don't think so. Is there ever a case where copying over the network would be slower than copying on the server? Mybe not, but if the copy will take a minute, then we don't want to tie up an rpc slot for a minute. --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
