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From: brent@terra.Eng.Sun.COM (Brent Callaghan)
Newsgroups: comp.protocols.nfs
Subject: Re: perculiar NFS behaviour
Message-ID: <11700@exodus.Eng.Sun.COM>
Date: 17 Apr 91 05:36:55 GMT
References: <1991Apr15.045511.6354@massey.ac.nz> <130@gordius.gordian.com>
Sender: news@exodus.Eng.Sun.COM
Lines: 27

In article <130@gordius.gordian.com>, johnk@gordian.com (John Kalucki) writes:
> ...but what I'd really like is some method to allow me to umount a
> dead nfs filesystem.

What's the problem ?  SunOS lets you unmount a dead NFS filesystem.

The same should be true for other implementations - the client's
kernel does not need to communicate with the server in order to
do an unmount.  After the unmount is complete the umount command
will do the server a courtesy and send an unmount message to it's
mount daemon - but's no big deal if this times out.

On the other hand, if you can easily get an umountable mount if
you have hierarchically related mounts e.g.  if /usr/local and
/usr/local/share are two NFS mounts and the server for /usr/local
falls over then heaven and earth won't shift the mounts.  Why ?

Can't unmount /usr/local because the sub-mount of /usr/local/share
keeps it EBUSY.

Can't unmount /usr/local/share because the unmount system call will
hang in the pathname lookup when it hits /usr/local.
--

Made in New Zealand -->  Brent Callaghan  @ Sun Microsystems
			 Email: brent@Eng.Sun.COM
			 phone: (415) 336 1051