On Tue, Apr 14, 2015 at 01:16:13PM -0400, Anna Schumaker wrote: > On 04/14/2015 12:53 PM, Christoph Hellwig wrote: > > On Sat, Apr 11, 2015 at 09:04:02AM -0400, Jeff Layton wrote: > >> Yuck! How the heck do you clean up the mess if that happens? I > >> guess you're just stuck redoing the copy with normal READ/WRITE? > >> > >> Maybe we need to have the interface return a hard error in that > >> case and not try to give back any sort of offset? > > > > The NFSv4.2 COPY interface is a train wreck. At least for Linux I'd > > expect us to simply ignore it and only implement my new CLONE > > operation with sane semantics. That is unless someone can show some > > real life use case for the inter server copy, in which case we'll > > have to deal with that mess. But getting that one right at the VFS > > level will be a nightmare anyway. > > > > Make this a vote from me to not support partial copies and just > > return and error in that case. > > Agreed. Looking at the v4.2 spec, COPY does take ca_consecutive and a > ca_synchronous flags that let the client state if the copy should be > done consecutively or synchronously. I expected to always set > consecutive to "true" for the Linux client. That's supposed to mean results are well-defined in the partial-copy case, but I think Christoph's suggesting eliminating the partial-copy case entirely? Which would be fine with me. It might actually have been me advocating for partial copies. But that was only because a partial-copy-handling-loop seemed simpler to me than progress callbacks if we were going to support long-running copies. I'm happy enough not to have it at all. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
