Re: [PATCH] NFS: Fix send buffer length calculation in nfs3_xdr_setaclargs()

[Suresh Jayaraman <sjayaraman@suse.de>]

Trond Myklebust wrote:
> On Wed, 2009-04-15 at 19:40 +0530, Suresh Jayaraman wrote:
>> The recent posixacl fix(commit ae46141ff08f1965b17c531b571953c39ce8b9e2)
>> seems to have introduced a bug that will lead to -EINVAL errors during
>> normal setfacl operations on file or dir. This patch attempts to fix
>> this.
> 
> To start with, your len_in_head is in units of 32-bit _words_, whereas
> len, base, and req->rq_slen are in units of bytes.
> 
> Then, 'len' is initialised to the length of the currently encoded part
> of the RPC header before subtracting 'len_in_head'. The resulting number

Doh, I got it wrong totally. Thanks for the explaination.

On a side note, I think it would be nice to add little comments in xdr
code to explain non-obvious pieces.

> 
> Please check if the following patch fixes things for you.

Yes, the below patch fixes the issue for me too.

Thanks,

> Trond
> ------------------------------------------------------------
>>From b273b42f8b793a4a446015b50a5c1473553af48b Mon Sep 17 00:00:00 2001
> From: Trond Myklebust <Trond.Myklebust@netapp.com>
> Date: Wed, 15 Apr 2009 13:58:45 -0400
> Subject: [PATCH] NFS: Fix the XDR iovec calculation in nfs3_xdr_setaclargs
> 
> Commit ae46141ff08f1965b17c531b571953c39ce8b9e2 (NFSv3: Fix posix ACL code)
> introduces a bug in the calculation of the XDR header iovec. In the case
> where we are inlining the acls, we need to adjust the length of the iovec
> req->rq_svec, in addition to adjusting the total buffer length.
> 
> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
> ---
>  fs/nfs/nfs3xdr.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
> index e6a1932..35869a4 100644
> --- a/fs/nfs/nfs3xdr.c
> +++ b/fs/nfs/nfs3xdr.c
> @@ -713,7 +713,8 @@ nfs3_xdr_setaclargs(struct rpc_rqst *req, __be32 *p,
>  	if (args->npages != 0)
>  		xdr_encode_pages(buf, args->pages, 0, args->len);
>  	else
> -		req->rq_slen += args->len;
> +		req->rq_slen = xdr_adjust_iovec(req->rq_svec,
> +				p + XDR_QUADLEN(args->len));
>  
>  	err = nfsacl_encode(buf, base, args->inode,
>  			    (args->mask & NFS_ACL) ?


-- 
Suresh Jayaraman