Re: [PATCH] nfsd41: check the size of response

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

On Wed, May 18, 2011 at 10:19:23AM +0800, Mi Jinlong wrote:
> Compare response's size to the session se_fmaxresp_sz and 
> se_fmaxresp_cached at the same function.
> 
> And modify function name nfsd4_check_drc_limit to
> nfsd4_check_response_size.

Hm.  I guess that's OK.  Note we have a bigger problem, though, which is
that we're waiting too late to check these limits:

	http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues#DRC_limit_checking

Have you looked at that list, by the way?:

	http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues#Highest_priority

Those are the 4.1 spec compliance problems that I think are the most
important to fix--the ones that I think we have to get done before we
can really declare the 4.1 server correct.

--b.

> 
> Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
> ---
>  fs/nfsd/nfs4xdr.c |   20 ++++++++++++--------
>  1 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index c6766af..a7cf985 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -3224,12 +3224,12 @@ static nfsd4_enc nfsd4_enc_ops[] = {
>   * pad: add on 8 bytes for the next operation's op_code and status so that
>   * there is room to cache a failure on the next operation.
>   *
> - * Compare this length to the session se_fmaxresp_cached.
> + * Compare this length to the session se_fmaxresp_sz and se_fmaxresp_cached.
>   *
>   * Our se_fmaxresp_cached will always be a multiple of PAGE_SIZE, and so
>   * will be at least a page and will therefore hold the xdr_buf head.
>   */
> -static int nfsd4_check_drc_limit(struct nfsd4_compoundres *resp)
> +static int nfsd4_check_response_size(struct nfsd4_compoundres *resp)
>  {
>  	int status = 0;
>  	struct xdr_buf *xb = &resp->rqstp->rq_res;
> @@ -3242,7 +3242,7 @@ static int nfsd4_check_drc_limit(struct nfsd4_compoundres *resp)
>  		return status;
>  
>  	session = resp->cstate.session;
> -	if (session == NULL || slot->sl_cachethis == 0)
> +	if (session == NULL)
>  		return status;
>  
>  	if (resp->opcnt >= args->opcnt)
> @@ -3259,10 +3259,14 @@ static int nfsd4_check_drc_limit(struct nfsd4_compoundres *resp)
>  	dprintk("%s length %u, xb->page_len %u tlen %u pad %u\n", __func__,
>  		length, xb->page_len, tlen, pad);
>  
> -	if (length <= session->se_fchannel.maxresp_cached)
> -		return status;
> -	else
> +	if (length > session->se_fchannel.maxresp_sz)
> +		return nfserr_rep_too_big;
> +
> +	if (slot->sl_cachethis == 1 &&
> +	    length > session->se_fchannel.maxresp_cached)
>  		return nfserr_rep_too_big_to_cache;
> +
> +	return status;
>  }
>  
>  void
> @@ -3282,8 +3286,8 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
>  	       !nfsd4_enc_ops[op->opnum]);
>  	op->status = nfsd4_enc_ops[op->opnum](resp, op->status, &op->u);
>  	/* nfsd4_check_drc_limit guarantees enough room for error status */
> -	if (!op->status && nfsd4_check_drc_limit(resp))
> -		op->status = nfserr_rep_too_big_to_cache;
> +	if (!op->status)
> +		op->status = nfsd4_check_response_size(resp);
>  status:
>  	/*
>  	 * Note: We write the status directly, instead of using WRITE32(),
> -- 
> 1.7.4.5
> 
>