Re: [PATCH 2/6] nfsd: swap fs root in NFSd kthreads

[Stanislav Kinsbursky]

11.12.2012 18:54, Al Viro ÐÐÑÐÑ:
> On Tue, Dec 11, 2012 at 06:00:00PM +0400, Stanislav Kinsbursky wrote:
> > 11.12.2012 00:28, J. Bruce Fields ??????????:
> > > On Thu, Dec 06, 2012 at 06:34:47PM +0300, Stanislav Kinsbursky wrote:
> > > > NFSd does lookup. Lookup is done starting from current->fs->root.
> > > > NFSd is a kthread, cloned by kthreadd, and thus have global (but luckely
> > > > unshared) root.
> > > > So we have to swap root to those, which process, started NFSd, has. Because
> > > > that process can be in a container with it's own root.
> > >
> > > This doesn't sound right to me.
> > >
> > > Which lookups exactly do you see being done relative to
> > > current->fs->root ?
> >
> > Ok, you are right. I was mistaken here.
> > This is not a exactly lookup, but d_path() problem in svc_export_request().
> > I.e. without root swapping, d_path() will give not local export path (like "/export")
> > but something like this "/root/containers_root/export".
>
> Now, *that* is a different story (and makes some sense).  Take a look
> at __d_path(), please.  You don't need to set ->fs->root to get d_path()
> equivalent relative to given point.

Thanks, Al.
But __d_path() is not exported and this code is called from NFSd module.
Is it suitable for you to export __d_path()?

--
Best regards,
Stanislav Kinsbursky
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