On Jun 12, 2008, at 12:57 PM, Trond Myklebust wrote:
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.
The default transport timer settings are the same for both NFS and
NFSv4, so I thought it would be best to put a single copy of that
logic in a common code path.
I suppose we could just factor it into a helper and have both the NFS
and NFSv4 mount paths call this, but I'm not sure what the value of
that would be.
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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