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Message-Id: <199809111327.JAA15754@freebie.dp.ny.frb.org>
Date: Fri, 11 Sep 1998 09:27:44 -0400 (EDT)
From: seth@freebie.dp.ny.frb.org
Reply-To: seth@freebie.dp.ny.frb.org
To: FreeBSD-gnats-submit@freebsd.org
Subject: multiple identical NFS mounts accepted
X-Send-Pr-Version: 3.2

>Number:         7895
>Category:       bin
>Synopsis:       multiple identical NFS mounts accepted
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Sep 11 06:30:01 PDT 1998
>Closed-Date:    Wed Mar 28 13:18:11 PST 2001
>Last-Modified:  Wed Mar 28 13:25:49 PST 2001
>Originator:     Zippy
>Release:        FreeBSD 2.2.7-RELEASE i386
>Organization:
none
>Environment:



>Description:

multiple identical nfs mounts (from the same exported fs to the same
mountpoint) are accepted and each is given an entry in 'mount' output.



>How-To-Repeat:

easy.  Two ways:

have an nfs mount in /etc/fstab, and do a mount -a twice, or manually
nfs-mount the same fs twice:

# mount netserv3:/export/freebie/usr/packages-2.2.7 /usr/packages
# mount netserv3:/export/freebie/usr/packages-2.2.7 /usr/packages

# mount
/dev/wd0s1a on / (local)
/dev/wd0s1f on /tmp (local)
/dev/wd0s1g on /usr (NFS exported, local)
/dev/wd0s1e on /var (local)
netserv3:/export/freebie/usr/packages-2.2.7 on /usr/packages
netserv3:/export/freebie/usr/backup on /usr/backup
procfs on /proc (local)
netserv3:/export/freebie/usr/packages-2.2.7 on /usr/packages

Umounting /usr/packages will umount the most-recently-mounted instance.

Add'l info:

# what `which mount`
/sbin/mount:
         Copyright (c) 1980, 1989, 1993, 1994
        mount.c 8.19 (Berkeley) 4/19/94
         Copyright (c) 1993, 1994
        mount_ufs.c     8.2 (Berkeley) 3/27/94
        getmntopts.c    8.1 (Berkeley) 3/27/94

>Fix:
	
Don't know exactly, but mount needs to check to see that the mountpoint isn't
already being used as such.
>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed 
State-Changed-By: iedowse 
State-Changed-When: Wed Mar 28 13:18:11 PST 2001 
State-Changed-Why:  
The ability to stack multiple filesystems over a single mountpoint 
is not a bug. Attempting to `fix' this by having mount(8) check 
for an existing similar mount is likely to break some chroot or 
jail configurations. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=7895 
>Unformatted:
