exportfs problem (summary, sort-of)

From: Jay Schlegel x6878 (jay@intermec.com)
Date: Mon Feb 05 1990 - 19:32:18 CST

  About a week ago I posted regarding difficulties exporting /usr from a server
to one of it's diskless clients, allowing root access.

  3 things I failed to indicate in my original posting (apologies):

    o /usr/local and /usr/src *are* separate filesystems (/usr not re-exported)

    o I had /usr mounted rw on the client (not that it matters, I was only
       trying to read L.sys!).

    o I'm not using a nameserver, the yp hosts lookup isn't failing,
       "tsunami" *is* the first name listed in /etc/hosts for the client.

  Quick Summary: I'd rather go back to patching "nobody" to 0 in the kernel!!!

  Long Summary (sort of a summary, sort of long):

  One or two mentioned that having "-access=host:host:host" might help.
Well, apart from it being undocumented that "-access" has anything to do
with root access to a mounted filesystem (notice that I'm not saying it isn't
so!), maintaining the list of hosts or a netgroup list would be cumbersome and
generally unacceptable (even if it did work). I haven't had the opportunity
to try this, I've been destructive enough lately (read-on).

  A couple of folks out there mentioned that exporting a symlink to /usr can
cause problems, e.g. the re-export of /usr via exporting the link nukes the
prior mount. While I have been unable to prove or disprove this, I find it
(nearly) beyond belief that Sun's _default_setup_ for a fileserver
(see exportfs listing below) would be so blatantly illegal.

  Still, this seems to be the most likely cause (to date):

"ls" of a couple of links exported in 4.0.3 default fileserver setup
(sun3 serving sun3 and sun3x):
lrwxrwxrwx 1 root wheel 4 Jan 11 17:18 /export/exec/sun3x -> sun3
lrwxrwxrwx 1 root wheel 4 Jan 11 17:18 /export/exec/sun3 -> /usr

Yes, this *is* what suninstall does, a symlink to a symlink to /usr!
I noticed this at install time and laughed heartily (probably doesn't make
any difference, but it's certainly convoluted).

A simple "exportfs" on the server includes (irrelevant lines edited out):
/usr -anon=0,root=tsunami:ra:drizzle

  Problem here is that unexporting /export/exec/sun3 sent all the clients
out to lunch (whoops)! I made the naive (and incorrect) assumption that
active mounts would be unaffected by changes to the export table.

  I could adjust fstab on all clients (to mount /usr instead of
/export/exec/sun3(x)) and adjust exports removing the symlink entries to find
out if the exported links are to blame (at this point, I believe that they are).

  Probly next time I'm here off-hours I'll give it a try.

  In the mean-time, I've established a work-around. :-)

Thanks to all who responded. Apologies for not providing the definitive answer.

-*jay Jay Schlegel --> Intermec Corp., Everett Wa.
        jay@intermec.com OR --> uunet!pilchuck!intermec!jay

This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:05:56 CDT