[pnfs] [Fwd: [PATCH] update exchange id reply to draft 9]

[J. Bruce Fields]

On Mon, Mar 05, 2007 at 11:13:33AM -0800, Marc Eshel wrote:
> "J. Bruce Fields" <bfields at fieldses.org> wrote on 03/05/2007 11:02:56 AM:
> 
> > On Sun, Mar 04, 2007 at 10:22:12PM -0800, Marc Eshel wrote:
> > > static int nfs4_proc_exchange_id(struct nfs4_client *clp)
> > > {
> > >         nfs4_verifier verifier;
> > >         struct nfs41_exchange_id_args args;
> > >         struct nfs41_exchange_id_res res = {
> > 
> > If this is client-generated then we can allocate the minimum we know we
> > need; looks like 40 bytes or so would do the job?  But just use some
> > other constant--please don't change NFS4_OPAQUE_LIMIT.
> 
> Like the comment states this a temporary fix until we remove those struct 
> from the stack.

Actually with the id down to a few tens of bytes it's probably OK on the
stack.  So it's simple enough just to do something like:

+#define MAX_EXCHANGE_ID_SIZE 50
+
 struct nfs41_exchange_id_args {
 	nfs4_verifier *			verifier;
 	unsigned int 			id_len;
-	char 				id[NFS4_OPAQUE_LIMIT];
+	char 				id[MAX_EXCHANGE_ID_SIZE];
 };
 
> > > struct nfs41_exchange_id_args {
> > >         nfs4_verifier *                 verifier;
> > >         unsigned int                    id_len;
> > >         char                            id[NFS4_OPAQUE_LIMIT];
> > >         u32                             flags;
> > >         struct nfs_impl_id4             impl_id;
> > >         clientid4                       clientid;
> > >         u32                             seqid;
> > > };
> > 
> > I thought the implementation id was optional.  How about we just set it
> > to zero?
> 
> But we still need to be ready to receive up to 1024 for each on of those 
> fields from some server implementation.

Nah, we can just throw them away at xdr decode time.  We're not using
them for anything, right?

--b.