Re: [PATCH 16/17] lockd: Start PF_INET6 listener only if IPv6 support isavailable

[Trond Myklebust <Trond.Myklebust@netapp.com>]

On Tue, 2009-03-03 at 15:34 -0700, Chuck Lever wrote:
> Apparently a lot of people need to disable IPv6 completely on their
> distributor-built systems, which have CONFIG_IPV6_MODULE enabled.
> 
> They do this by blacklisting the ipv6.ko module.  This causes the
> creation of the lockd service listener to fail if CONFIG_IPV6_MODULE
> is set, but the module cannot be loaded.
> 
> Now that the kernel's PF_INET6 RPC listeners are completely separate
> from PF_INET listeners, we can always start PF_INET.  Then lockd can
> try to start PF_INET6, but it isn't required to be available.
> 
> Note this has the added benefit that NLM callbacks from AF_INET6
> servers will never come from AF_INET remotes.  We no longer have to
> worry about matching mapped IPv4 addresses to AF_INET when comparing
> addresses.
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
> 
>  fs/lockd/svc.c |   28 ++++++++++++++++++++--------
>  1 files changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> index 566932b..4342b41 100644
> --- a/fs/lockd/svc.c
> +++ b/fs/lockd/svc.c
> @@ -194,19 +194,29 @@ lockd(void *vrqstp)
>  }
> 
>  static int create_lockd_listener(struct svc_serv *serv, char *name,
> -                                unsigned short port)
> +                                const int family, const unsigned
> short port)
>  {
>         struct svc_xprt *xprt;
> 
> -       xprt = svc_find_xprt(serv, name, 0, 0);
> +       xprt = svc_find_xprt(serv, name, family, 0);
>         if (xprt == NULL)
> -               return svc_create_xprt(serv, name, PF_INET,
> -                                       port, SVC_SOCK_DEFAULTS);
> -
> +               return svc_create_xprt(serv, name, family, port,
> +                                               SVC_SOCK_DEFAULTS);
>         svc_xprt_put(xprt);
>         return 0;
>  }
> 
> +static int create_lockd_family(struct svc_serv *serv, const int
> family)
> +{
> +       int err;
> +
> +       err = create_lockd_listener(serv, "udp", family, nlm_udpport);
> +       if (err < 0)
> +               return err;
> +
> +       return create_lockd_listener(serv, "tcp", family,
> nlm_tcpport);
> +}
> +
>  /*
>   * Ensure there are active UDP and TCP listeners for lockd.
>   *
> @@ -222,13 +232,15 @@ static int make_socks(struct svc_serv *serv)
>         static int warned;
>         int err;
> 
> -       err = create_lockd_listener(serv, "udp", nlm_udpport);
> +       err = create_lockd_family(serv, PF_INET);
>         if (err < 0)
>                 goto out_err;
> 
> -       err = create_lockd_listener(serv, "tcp", nlm_tcpport);
> -       if (err < 0)
> +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
> +       err = create_lockd_family(serv, PF_INET6);
> +       if (err < 0 && err != -EAFNOSUPPORT)
>                 goto out_err;
> +#endif /* CONFIG_IPV6 || CONFIG_IPV6_MODULE */
> 
>         warned = 0;
>         return 0;
> 
lockd_up: makesock failed, error=-98

IOW: EADDRINUSE

Isn't that call to IPV6_V6ONLY supposed to be set _before_ you bind the
socket to a particular port?

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com