On Tue, 08 Oct 2019 14:05:28 +0200 Christian Schoenebeck <qemu_...@crudebyte.com> wrote:
> On Dienstag, 8. Oktober 2019 11:14:59 CEST Greg Kurz wrote: > > > No, it is not a feature. It is still a fix. :) I cannot use 9p without > > > this > > > fix at all, so it is not some optional "feature" for me. > > > > I understand your need but this is still arguable. The 9p device has > > a limitation with cross-device setups. The actual bug is to silently > > cause inode number collisions in the guest. This is partly fixed by the > > "9p: Treat multiple devices on one export as an error" patch. Thinking > > again, it would even make sense to move "remap" from "9p: Added virtfs > > option 'multidevs=remap|forbid|warn'" to its own patch. We could then > > consider that the bug is fully fixed with "multidevs=forbid|warn". > > > > Then comes the "remap" feature which is expected to lift the limitation > > with cross-device setups, with a "not yet determined" performance cost > > and light reviewing of the code. > > Are these patch transfer requests addressed at me to be done? > It would certainly be appreciated :) and if it happens to be done before 2019-10-29, it can even be shipped with QEMU 4.2. > > Also, I strongly recommend you try out "virtio-fs" which is > > going to be soon the production grade way of sharing files > > between host and guest. > > > > https://www.mail-archive.com/libvir-list@redhat.com/msg182457.html > > Yes I know, I am following the development of virtio-fs already of course. > However for me it is far too early to actually use it in a production > environment. It e.g. seems to require bleeding edge kernel versions. And the > real argument for switching from 9p to virtio-fs would be a significant > performance increase. However so far (correct me if I am wrong) I have not > seen benchmarks that would show that this was already the case (yet). > > I wonder though whether virtio-fs suffers from the same file ID collisions > problem when sharing multiple file systems. > I don't know. > What is your long-term plan for 9p? Will it be dropped completely after > virtio-fs became stable? > No, 9p will survive. The local backend has an advantage despite its various limitations: it is really easy to use. No extra command needed. I also want to keep the synth backend around for testing, but I'll gladly drop the proxy backend which is clearly superseded by virtio-fs. Cheers, -- Greg > Best regards, > Christian Schoenebeck > >
