On Mon, Sep 30, 2013 at 4:49 PM, Ric Wheeler <rwheeler@xxxxxxxxxx> wrote: > On 09/30/2013 10:46 AM, Miklos Szeredi wrote: >> >> On Mon, Sep 30, 2013 at 4:41 PM, Ric Wheeler <rwheeler@xxxxxxxxxx> wrote: >>> >>> The way the array based offload (and some software side reflink works) is >>> not a byte by byte copy. We cannot assume that a valid count can be >>> returned >>> or that such a count would be an indication of a sequential segment of >>> good >>> data. The whole thing would normally have to be reissued. >>> >>> To make that a true assumption, you would have to mandate that in each of >>> the specifications (and sw targets)... >> >> You're missing my point. >> >> - user issues SIZE_MAX splice request >> - fs issues *64M* (or whatever) request to offload >> - when that completes *fully* then we return 64M to userspace >> - if it completes partially, then we return an error to userspace >> >> Again, wouldn't that work? >> >> Thanks, >> Miklos > > > Yes, if you send a copy offload command and it works, you can assume that it > worked fully. It would be pretty interesting if that were not true :) > > If it fails, we cannot assume anything about partial completion. Sure, that was my understanding from the start. Maybe I wasn't precise enough in my explanation. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
