On Thu, 2011-12-15 at 11:40 -0500, Loke, Chetan wrote: > > > > > > Why not support something like the async-iocb? > > > > You could, but that would tie copyfile() to the aio interface which was > > one of the things that I believe Al was opposed to when we discussed > > this at LSF/MM-2010. > > > > virtualization vendors who support this offload do it at a layer above the guest-OS(Intra-LUN(tm) locking or whatever fancy locking). So I think 'copyfile' is going to be appealing to application-developers more than the hypervisor-vendors. The application is thin provisioning, not the 'cp' command. When virtualisation vendors do support this, it will mainly be as part of their image management toolkits, not the hypervisor. > So let's think about it from end-users perspective: > Won't everyone replicate code to check - 'Am I done'? It will just make application folks write more (ugly)code. Because you would then have to maintain another queue/etc to check for this operation. 'Am I done' is easy: copyfile() returns with the number of bytes that have been copied. 'Is my copyfile() syscall making progress' is the question that needs answering. > We can just support full-copy. Partial copies can be returned as failure. Then you have to check the entire range on error instead of just resuming the copy from where it stopped. -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com -- 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
