misc/178113: tmpmfs rc.conf setting ignored

[Richard]

>Number:         178113
>Category:       misc
>Synopsis:       tmpmfs rc.conf setting ignored
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Apr 24 18:00:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Richard
>Release:        9.1
>Organization:
>Environment:
FreeBSD graphite 9.1-RELEASE FreeBSD 9.1-RELEASE #0 r243826: Tue Dec  4 06:55:39 UTC 2012     root at obrian.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
The system is being booted from a MD (MemDisk), i.e. from a CD ISO image, where:
* rc.conf contains: tmpmfs="AUTO" or "YES"
* the root file system is read-only
* the root file system contains /tmp

In this situation a new readable /tmp is not created.
This works with BSD 7.4, but no longer in 9.1

The error is in /etc/rc.d/tmp, where a new function 'mount_tmpmfs' fails to mount the desired device because a test to see if /tmp is not already on a 'md' device fails.

The obvious solution is to remove the check - but I presume it was added for a reason.  So the "correct" solution is not so trivial - would need to check that '/tmp' was on the same device as '/' ?
>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: