Date:   Tue, 2 Apr 2019 20:36:22 -0400
From:   "J. Bruce Fields" <bfields@redhat.com>
To:     Trond Myklebust <trondmy@gmail.com>
Cc:     linux-nfs@vger.kernel.org
Subject: Re: [PATCH 0/6] Allow containerised knfsd to set supported NFS
 versions
Message-ID: <20190403003619.GA11222@parsley.fieldses.org>
References: <20190402231448.27743-1-trond.myklebust@hammerspace.com>
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On Tue, Apr 02, 2019 at 04:14:42PM -0700, Trond Myklebust wrote:
> The current knfsd implementation is unable to support containers that
> want to run different combinations of NFS versions. This is because of
> the way we define which versions are supported: by directly editing the
> global version table in 'nfsd_program'.
> The following patch set modifies the method used to define version
> information by moving some of the server RPC request initialisation
> down into knfsd itself, allowing it to manage the version-specific
> initialisation.

Sounds fine, though I'm curious what the motivation is.

I assume the current behavior is that setting versions from any
container sets them globally (rather than erroring out or something)--so
is there any way some can detect whether they've got the new behavior
other than trying it and seeing what the result is in another container?

--b.

> 
> Note that we might want to consider a few follow ups to this patchset
> to get rid of some of the version-specific flags (e.g. vs_hidden) that
> currently need to be managed in the generic SUNRPC server code on behalf
> of just one or two RPC programs. These flags can easily by replaced by
> custom RPC request initialisers.
> 
> Trond Myklebust (6):
>   SUNRPC/nfs: Fix return value for nfs4_callback_compound()
>   SUNRPC: Add a callback to initialise server requests
>   SUNRPC: Clean up generic dispatcher code
>   SUNRPC: Allow further customisation of RPC program registration
>   nfsd: Add custom rpcbind callbacks for knfsd
>   nfsd: Allow containers to set supported nfs versions
> 
>  fs/lockd/svc.c             |   4 +-
>  fs/nfs/callback.c          |   2 +
>  fs/nfs/callback_xdr.c      |   2 +-
>  fs/nfsd/netns.h            |   8 +
>  fs/nfsd/nfs4proc.c         |   3 +-
>  fs/nfsd/nfsctl.c           |  25 +--
>  fs/nfsd/nfsd.h             |   8 +-
>  fs/nfsd/nfssvc.c           | 251 +++++++++++++++++++++++++-----
>  include/linux/sunrpc/svc.h |  33 ++++
>  net/sunrpc/svc.c           | 310 ++++++++++++++++++++++++-------------
>  10 files changed, 480 insertions(+), 166 deletions(-)
> 
> -- 
> 2.20.1
>