On Sep 9, 2008, at Sep 9, 2008, 2:20 PM, ebiederm@xxxxxxxxxxxx wrote:
Chuck Lever <chuck.lever@xxxxxxxxxx> writes:
If the upper layers are responsible for providing the utsname, you
will need to
fix up lockd and the NFS server's callback client too, at least.
Actually looking at the code. It looks like a proper fix may be
even simpler.
Why do we have both clnt->cl_server and clnt->cl_nodename? Or is
cl_server
the other side of the connection?
cl_server is the server-side. cl_nodename is the "machine name" of
the client.
What are we trying to achieve by reading utsname?
It looks like it gets copied into the sunrpc messages so I assume
it is
a part of the sunrpc spec?
It appears to be used only for RPC's AUTH_SYS credentials. The
nodename is used
to identify the caller's host. See RFC 1831, Appendix A:
http://rfclibrary.hosting.com/rfc/rfc1831/rfc1831-16.asp
Thanks that helps a lot.
I'm not terribly familiar with uts namespaces, though. Can someone
explain why
we need to distinguish between these for AUTH_SYS if the caller is
on a remote
system?
Semantically processes in different uts namespaces are on different
machines.
OK.
I don't like the idea of an oops in here. Instead, (for now) it
should warn and
fail to create the client, IMO.
Which is interesting when the problem happens during NFS unmount.
Although
frankly it could fail anyway.
It seems strange that we are creating a client during unmount anyway.
It's worth investigating. Just enable RPC tracing (/usr/sbin/rpcdebug
-m rpc -s all) before shutting down the client.
NFS unmounting is historically difficult because during a system
shutdown, unmounting is the last thing to occur, and usually happens
after most system services (such as the portmapper service) have
become unavailable. That's fine for local file systems, but it makes
for a rather dodgy situation for NFS.
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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