Re: [RFC PATCH 5/8] KEYS: exec request-key within the requesting task's init namespace

From: J. Bruce Fields
Date: Fri Feb 20 2015 - 14:05:52 EST


On Fri, Feb 20, 2015 at 12:07:15PM -0600, Eric W. Biederman wrote:
> "J. Bruce Fields" <bfields@xxxxxxxxxxxx> writes:
>
> > On Fri, Feb 20, 2015 at 05:33:25PM +0800, Ian Kent wrote:
>
> >> The case of nfsd state-recovery might be similar but you'll need to help
> >> me out a bit with that too.
> >
> > Each network namespace can have its own virtual nfs server. Servers can
> > be started and stopped independently per network namespace. We decide
> > which server should handle an incoming rpc by looking at the network
> > namespace associated with the socket that it arrived over.
> >
> > A server is started by the rpc.nfsd command writing a value into a magic
> > file somewhere.
>
> nit. Unless I am completely turned around that file is on the nfsd
> filesystem, that lives in fs/nfsd/nfs.c.
>
> So I bevelive this really is a case of figuring out what we want the
> semantics to be for mount and propogating the information down from
> mount to where we call the user mode helpers.

Oops, I agree. So when I said:

The upcalls need to happen consistently in one context for a
given virtual nfs server, and that context should probably be
derived from rpc.nfsd's somehow.

Instead of "rpc.nfsd's", I think I should have said "the mounter of
the nfsd filesystem".

Which is already how we choose a net namespace: nfsd_mount and
nfsd_fill_super store the current net namespace in s_fs_info. (And then
grep for "netns" to see the places where that's used.)

--b.
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