Re: [PATCH 0/2] mountd: clean up rmtab handling

[Jeff Layton <jlayton@redhat.com>]

Neil Brown wrote:
 >
 > Does that make sense?

Yes. Thanks for explaining that -- it makes total sense now. I was focusing
on auth_authenticate, which I don't think would behave differently, but you're
clearly correct that we'd need to ensure the same for the kernel caches.

 >> As you said, neither the rmtab or the kernel cache is an ideal place to pull
 >> this info. So, my inclincation is to stick with the rmtab, and simply have it
 >> track what we know is trackable -- mount and unmount calls into mountd. I
 >> think having false positives is preferable to possibly having some mounts
 >> that are not reflected at all because they have gone idle.
 >
 > Ok, how about this as a way forward.
 >
 >  1/ remove that 'my_client' caching.
 >  2/ Remove the updates of rmtab on client upcalls and simply do rmtab
 >     updates with hostname (from get_reliable_hostbyaddr) and path name
 >     from MOUNT or UMOUNT requests
 >  3/ Add -I flag which:
 >       passes IP address rather than client_compose name to kernel and
 >       adds rmtab entries on kernel upcalls.  It also hard-removes
 >       rmtab entries on 'UMOUNT' and flush the kernel cache so that the
 >       next access for that host/path causes an upcall.
 >  4/ Add a -? flag (haven't chosen a letter yet) which:
 >       implies -I, but when asked for a 'DUMP', it calls gethosytbyname
 >       on each IP address to ge a hostname.
 >
 > Then the default would be vaguely usable, and more precise information
 > would be available (at a cost).
 >

At first glance, that sounds reasonable. I'll have a closer look at the code
and your idea and see if I can come up with a patch.

 >> Either way, a manpage update is probably also in order to outline the folly
 >> of depending on showmount -a :-).
 >
 > Yes, I would happily accept a patch making such a change.
 >

Once we come to consensus on a code patch, I'll have a look at what manpage
changes need to be made.

Thanks,
Jeff


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