On Tue, 7 Apr 2009 19:14:06 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
> On Tue, Apr 07, 2009 at 03:43:39PM -0400, Tom Talpey wrote:
> > At 01:11 PM 4/7/2009, Jeff Layton wrote:
> > >On Tue, 07 Apr 2009 12:27:49 -0400
> > >Tom Talpey <tmtalpey@xxxxxxxxx> wrote:
> > >
> > >> At 12:02 PM 4/7/2009, Chuck Lever wrote:
> > >> >
> > >> >On Apr 7, 2009, at 11:25 AM, Jeff Layton wrote:
> > >> >> + /* Use standard NFS port for NFSv4 */
> > >> >> + if (program == 100003 && version == 4) {
> > >> >> + port = 2049;
> > >> >> + goto set_port;
> > >> >> + }
> > >> >
> > >> >I think this patch set looks pretty reasonable. Here's my one
> > >> >remaining quibble.
> > >> >
> > >> >You can specify "port=" for nfs4 mounts, in which case we want to use
> > >> >that value here, too, I think. It would be simpler overall if the
> > >>
> > >> *Must* use a port= specification. The 2049 definition is only true for
> > >> NFSv4/TCP, as a counterexample the NFSv4/RDMA IANA binding is
> > >> port 20049. So slamming the port to 2049 would break NFSv4/RDMA.
> > >>
> > >
> > >rpc.gssd doesn't seem to be rdma-enabled at this point. It only seems
> > >to handle "tcp" and "udp" in the existing code.
> >
> > Fair enough. But hardwiring 2049 for all transports is going to very
> > problematic. What's the motivation for bypassing the rpcbind query
> > altogether (that "goto set_port" skips over it)? Why not at least
> > try the query first?
>
> We're just doing the rpcsec_gss context initiation. Normally that would
> be done over an already-established connection--the only reason we don't
> is because our implementation is split between the client and the
> server, so it's more convenient for us to set up a new connection in
> rpc.gssd. But we really shouldn't be doing an entirely new rpcbind
> call--somebody else already did that for us and is telling us the
> results through the rpc_pipefs info file.
>
Technically, the info file doesn't display the port from an rpcbind
call. That field is populated before the kernel's rpcbind call is
done. The contents will be one of:
- the value of the port= mount option if one was specified
- 2049 if it's an nfs4 mount and there is no port= option specified
- 0 if nfsv2/3 and no port= option was specified
...its real value is in allowing gssd to skip the rpcbind call if
someone specified port= when doing the mount. This could probably
be changed, but I'm not sure it's such a big deal. It only means an
extra rpcbind call at mount time for NFSv2/3. Further upcalls for
other creds by the same client don't incur extra rpcbind queries.
--
Jeff Layton <jlayton@xxxxxxxxxx>
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