Re: two /net paths to the same local mount?

[Ian Kent <raven@themaw.net>]

On Fri, 2010-07-09 at 15:04 -0700, Chris Quenelle wrote:
> Ian Kent wrote:
> 
> > strace output is often not very useful.
> > 
> > If you think there is some sort of deadlock going on get a sysreq-t dump
> > to syslog. We still haven't seen a debug log?
> 
> I've had reports that my emails are being delayed when they go out to the list.
> If anyone is following along and you'd like me to add you to my cc:
> lines so you get the email directly, let me know, and I'll do that.

That's going to happen if you post to a subscribers only list without
subscribing to it.

> 
> I'm getting close to my limits of what this problem is worth to me.

And yet you haven't really provided the information requested?

I don't remember but did we get the distribution and autofs version your
using?

> I suspect the two broken paths will get unwedged if I reboot the system.
> But I'd love to know how to prevent it from happening again.
> 
> I saw these lines in /var/log/messages:
> 
> > >>>> Jun 29 09:04:46 carabas automount[11786]: Debug logging set for /net
> > >>>> Jun 29 09:09:22 carabas automount[11786]: get_pkt: message pending on control fifo.
> > >>>> Jun 29 09:09:22 carabas automount[11786]: Basic logging set for /net
> 
> Does that mean that all debugging output from automount should be
> going to that file?  Or could the debug output still be going someplace
> else (or into /dev/null?) In between the first line of that log output and
> the last line, I provoked a correctly functioning automount of
> a local file system, and I also tried to access the "broken" path
> to the local filesystem.

What file, I don't understand what you mean?

But you don't mention what you have done to tell syslog to actually send
"all" facility daemon messages to the syslog.

Try having a look at Jeffs page http://people.redhat.com/jmoyer for a
description debug logging setup.

> 
> So that in combination with strace/automount not giving any output
> when I access the broken path, makes me think the control path
> is not getting out of the kernel.

Maybe.

> 
> Can you point me to an explanation of what a "sysreq-t dump" is and
> how to get it?  I don't have access to the console of this machine,
> hopefully it's something I can do from a root term window.

Wherever your distribution's has kernel documentation (or a package that
contains the documentation) look at Documentation/sysrq.txt.

Often, you will find you can:

echo "t" > /proc/sysrq-trigger

to get a trace dump, which is what I'm asking for.

> 
> To summarize my problem, I have a test set of paths to access a local
> filesystem, 7 work and 2 don't.
> 
> /net/carabas/export/home1
> /net/carabas/export/home2    <-- fails
> /net/carabas/export/home3    <-- fails
> /net/carabas.sfbay/export/home1
> /net/carabas.sfbay/export/home2
> /net/carabas.sfbay/export/home3
> /net/carabas.sfbay.sun.com/export/home1
> /net/carabas.sfbay.sun.com/export/home2
> /net/carabas.sfbay.sun.com/export/home3
> 
> 
> I don't see anythign suspicious in the output of:
> showmount
> df
> /etc/host.conf
> strace automount
> automount -l debug /net
> 
> 
> 
> 
> --chris