Messages in this thread | | | Date | Tue, 28 Mar 2023 11:31:50 +0900 | From | Dominique Martinet <> | Subject | Re: 9p caching with cache=loose and cache=fscache |
| |
Luis Chamberlain wrote on Mon, Mar 27, 2023 at 10:39:54AM -0700: > > I have fixed what > > I hope to be my last bug with the new patch series so it should be > > going into linux-next today. > > Nice, thanks, since kdevops relies on a host kernel though and we strive > to have stability for that, I personally like to recommend distro > kernels and so they're a few kernel releases out of date. So debian-testing > is on 6.1 as of today for example. > [...] > - opts: "ro,trans=virtio,version=9p2000.L,posixacl,cache=loose" > + opts: "ro,trans=virtio,version=9p2000.L,posixacl,cache=none"
Yes, if you want something mostly coherent with the host, cache=none (or cache=mmap if you need mmap, iirc linux build does for linking? if you want to do that on guest...) is what you'll want to use on current kernels.
> BTW the qemu wiki seems to suggest cache=loose and its why I used it on > kdevops as a default. What about the following so to avoid folks running > into similar issues? I can go and update the wiki too.
I've added Christian in Cc for this point, he's more active on the qemu side (thread started here: https://lkml.kernel.org/r/ZA0FEyOtRBvpIXbi@bombadil.infradead.org )
I have no opinion on the current wording, the default is there for a reason and it's a safe default (none), and cache=loose is clearly described with "no attempts are made at consistency, intended for exclusive, read-only mounts" which I think ought to be clear enough (exclusive means not shared with the host), but if you think it's not clear enough it probably isn't.
A word on the qemu wiki "if you want to share with host..." would probably be good though.
-- Dominique
| |