Re: [PATCH v2 1/5] ovl: return error on mount if metacopy cannot be enabled

[Vivek Goyal <vgoyal@redhat.com>]

On Thu, Nov 01, 2018 at 09:41:08PM +0100, Miklos Szeredi wrote:
> On Thu, Nov 1, 2018 at 2:11 PM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> > On Thu, Nov 1, 2018 at 2:03 PM, Vivek Goyal <vgoyal@redhat.com> wrote:
> >> On Thu, Nov 01, 2018 at 02:48:09AM +0200, Amir Goldstein wrote:
> >
> >>>
> >>>               case OPT_METACOPY_ON:
> >>>                       config->metacopy = true;
> >>> +                     config->strict = true;
> >>
> >> I think either ->strict should go in a separate patch or we should have
> >> a good description in commit message, explaining why ->strict is there
> >> and how it will impact behavior going forward.
> >
> > I'm redoing Amir's patches a bit, and at the moment I'm more inclined
> > to leave this after the merge window, since there are so many subtle
> > details to deal with.
> >
> > Back shortly with an updated set.
> 
> ...this is more complicated than I thought.
> 
> Anyway, pushed a metacopy fix to overlayfs-next, that I'm pretty happy with.
> 
> I don't think erroring out on noxattr is important; falling back is
> actually quite sane.  And it isn't going to be an issue in real life,
> since xattr is supported on lots of fs, and it's unlikely that lots of
> people will want to use overlayfs with e.g. minix as the upper layer.

Hi Miklos,

This looks reasonable to me. I tried metacopy=on and it mounted. Only
little issue seems to be that it enables redirect_dir but it does not
show in /proc/mounts.

#cat /proc/mounts | grep overlay
none /root/overlayfs-testing/merged overlay rw,seclabel,relatime,lowerdir=lower:lower2,upperdir=upper,workdir=work,metacopy=on 0 0

Is this an issue or it is fine given on same kernel configuration all
user has to pass is "metacopy=on" to get similar mount settings. Thought
of pointing it out to make sure this is not an issue.

Thanks
Vivek