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Date:   Wed, 7 Oct 2020 14:05:14 -0400
From:   "bfields@fieldses.org" <bfields@fieldses.org>
To:     Trond Myklebust <trondmy@hammerspace.com>
Cc:     "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "aglo@umich.edu" <aglo@umich.edu>,
        "bcodding@redhat.com" <bcodding@redhat.com>,
        "chuck.lever@oracle.com" <chuck.lever@oracle.com>
Subject: Re: unsharing tcp connections from different NFS mounts
Message-ID: <20201007180514.GG23452@fieldses.org>
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On Wed, Oct 07, 2020 at 05:29:26PM +0000, Trond Myklebust wrote:
> On Wed, 2020-10-07 at 13:15 -0400, Bruce Fields wrote:
> > Yeah, honestly I don't understand the details of that case either.
> > 
> > (There is one related thing I'm curious about, which is how close we
> > are
> > to keeping clients in different containers completely separate (which
> > we'd need, for example, if we were to ever permit unprivileged nfs
> > mounts).  It looks to me like as long as two network namespaces use
> > different client identifiers, the client should keep different state
> > for
> > them already?  Or is there more to do there?)
> 
> The containerised use case should already work. The containers have
> their own private uniquifiers, which can be changed
> via /sys/fs/nfs/net/nfs_client/identifier.

I was just looking at that commit (bf11fbd20b3 "NFS: Add sysfs support
for per-container identifier"), and I'm confused by it: it adds code to
nfs/sysfs to get and set "identifier", but nothing anywhere that
actually uses the value.  I can't figure out what I'm missing.

--b.

> In fact, there is also a udev trigger for that pseudofile, so my plan
> is (in my copious spare time) to write a /usr/lib/udev/nfs-set-
> identifier helper in order to manage the container uniquifier, to allow
> generation on the fly and persistence.
> 
> -- 
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com
> 
>