Re: [PATCH] NFSD: fix use of setsockopt

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Jun 19, 2008 at 09:33:39AM -0400, Olga Kornievskaia wrote:
> The following patch fixes NFS server's use of setsockopt. For this  
> function to take an effect it first needs be called after socket  
> creation but before sock binding.

The tcp(7) man page actually claims that it's listen() and connect()
that matter (so the setsockopt is effective on (and only on) unconnected
sockets), so probably this could go after the bind and before the
listen?  Not that it matters.

> This patch also changes the size of the receive sock buffer to be same  
> as the send sock buffer. Both buffers are now a multiple of maxpayload  
> and number of nfsd threads.

It would be nice if we could get some review from someone who remembers
what the justification for the smaller receive buffer size was (Neil?).

> This patch fixes the problem that receive window never opens beyond the  
> default TCP receive window size set by the 2nd parameter of the  
> net.ipv4.tcp_rmem sysctl.

Do you know what it does in the udp case?

--b.

>
> Signed-off-by: Olga Kornievskaia <aglo@citi.umich.edu>

> diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
> index c75bffe..178b397 100644
> --- a/net/sunrpc/svcsock.c
> +++ b/net/sunrpc/svcsock.c
> @@ -1191,7 +1191,7 @@ svc_tcp_recvfrom(struct svc_rqst *rqstp)
>  		 */
>  		svc_sock_setbufsize(svsk->sk_sock,
>  				    (serv->sv_nrthreads+3) * serv->sv_max_mesg,
> -				    3 * serv->sv_max_mesg);
> +				    (serv->sv_nrthreads+3) * serv->sv_max_mesg);
>  
>  	clear_bit(SK_DATA, &svsk->sk_flags);
>  
> @@ -1372,11 +1372,6 @@ svc_tcp_init(struct svc_sock *svsk)
>  		 * receive and respond to one request.
>  		 * svc_tcp_recvfrom will re-adjust if necessary
>  		 */
> -		svc_sock_setbufsize(svsk->sk_sock,
> -				    3 * svsk->sk_server->sv_max_mesg,
> -				    3 * svsk->sk_server->sv_max_mesg);
> -
> -		set_bit(SK_CHNGBUF, &svsk->sk_flags);
>  		set_bit(SK_DATA, &svsk->sk_flags);
>  		if (sk->sk_state != TCP_ESTABLISHED)
>  			set_bit(SK_CLOSE, &svsk->sk_flags);
> @@ -1761,6 +1756,8 @@ static int svc_create_socket(struct svc_serv *serv, int protocol,
>  
>  	if (type == SOCK_STREAM)
>  		sock->sk->sk_reuse = 1;		/* allow address reuse */
> +	svc_sock_setbufsize(sock, (serv->sv_nrthreads+3) * serv->sv_max_mesg,
> +				(serv->sv_nrthreads+3) * serv->sv_max_mesg);
>  	error = kernel_bind(sock, sin, len);
>  	if (error < 0)
>  		goto bummer;