Re: [PATCH 4/5] NFS: set transport defaults after mount option parsing is finished

[Trond Myklebust <Trond.Myklebust@netapp.com>]

On Thu, 2008-06-12 at 12:37 -0400, Chuck Lever wrote:
> Address some unfortunate mount option parsing behavior by setting certain
> transport-based defaults *after* option parsing is complete.
> 
>  o  Some options don't obey the "rightmost wins" rule.  Jeff Layton
>     noticed that specifying the "proto=" mount option after the "retrans"
>     or "timeo" options will cause the retrans and timeo values to be
>     overwritten with default settings.
> 
>     Allow these options to be specified in any order without unexpectedly
>     reverting retrans and timeo to their default.
> 
>  o  I've received several reports that text-based mounting through
>     firewalls that block UDP fails, even if "proto=tcp" is specified.
> 
>     If a user specifies "proto=tcp" via the legacy mount API, the mount
>     command also uses TCP to contact the server's mount daemon.  Ditto
>     for "proto=udp".  We want the kernel's mount option to emulate this
>     behavior; however, we still want the default mount protocol to be UDP
>     if no transport options were specified.

Why is it necessary to set these defaults in nfs_parse_mount_options?
This is quite unrelated to parsing of the mount string.

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com