From nobody  Mon Mar 24 19:24:58 1997
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Date: Mon, 24 Mar 1997 19:24:58 -0800 (PST)
From: richw@webcom.com
To: freebsd-gnats-submit@freebsd.org
Subject: Can't umount MFS file system
X-Send-Pr-Version: www-1.0

>Number:         3091
>Category:       kern
>Synopsis:       Can't umount MFS file system
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:
>Keywords:
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Mar 24 19:30:01 PST 1997
>Closed-Date:    Mon Mar 24 20:47:35 PST 1997
>Last-Modified:  Tue Mar 25 15:10:10 PST 1997
>Originator:     Rich Wales
>Release:        2.2-RELEASE
>Organization:
>Environment:
FreeBSD yank.kitchener.on.ca 2.2-RELEASE FreeBSD 2.2-RELEASE #0: Mon Mar 24 19:20:29 EST 1997     richw@yank.kitchener.on.ca:/home/src/sys/compile/YANK  i386
>Description:
I built a kernel with "options MFS" and mounted a MFS file system as
/tmp.  I am unable to unmount this file system.  "umount /tmp" fails
with "umount: /tmp: Device busy".

Even when going to single user mode, /tmp cannot be unmounted.  If I
try to force the issue via "umount -f /tmp" or "reboot", or by killing
the "mfs" process supporting /tmp, the kernel crashes with a page fault
(code 12).

The problem doesn't depend on the MFS file system being /tmp.  I tried
mounting an MFS file system as /mnt, with the same results.  I also
mounted /mnt while in single-user mode, and immediately tried to unmount
it, but the unmount still failed.
>How-To-Repeat:
Build a kernel with "options MFS".

Add a line like the following to /etc/fstab:

	/dev/wd0s2b	/tmp	mfs	rw,-s=50000	0	0

(substituting your swap partition as appropriate).

After the system is up multi-user, log in as root and "shutdown now".
Note how "some processes wouldn't die".  If you do "ps ax", you'll see
the "mfs" process for the /tmp file system is still around.

Forcibly unmount /tmp in any of the following ways:

	1.  reboot
	2.  umount -f /tmp
	3.  kill the "mfs" process

The kernel will die with a page-fault panic.
>Fix:

>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed 
State-Changed-By: gibbs 
State-Changed-When: Mon Mar 24 20:47:35 PST 1997 
State-Changed-Why:  
This bug has been fixed in current and the 2.2 branch.  The fix will be 
inlucded in the 2.2.1 release. 

From: j@uriah.heep.sax.de (J Wunsch)
To: richw@webcom.com
Cc: freebsd-gnats-submit@freebsd.org
Subject: Re: kern/3091: Can't umount MFS file system
Date: Tue, 25 Mar 1997 23:26:55 +0100

 As richw@webcom.com wrote:
 
 > >Synopsis:       Can't umount MFS file system
 
 That's a duplicate for PR # 3026, and can be closed as such.  It can
 also be closed since the problem has long since :) been fixed -- see
 the audit-trail of # 3026.
 
 -- 
 cheers, J"org
 
 joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
 Never trust an operating system you don't have sources for. ;-)
>Unformatted:
