kern/45709: tmpfs size went nuts

[Taylor R Campbell <campbell+netbsd%mumble.net@localhost>]

>Number:         45709
>Category:       kern
>Synopsis:       tmpfs size went nuts
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Dec 13 17:35:00 +0000 2011
>Originator:     Taylor R Campbell <campbell+netbsd%mumble.net@localhost>
>Release:        NetBSD 5.99.58
>Organization:
>Environment:
System: NetBSD oberon.local 5.99.58 NetBSD 5.99.58 (RIAMONOHACK) #4: Sat Dec 10 
23:18:29 UTC 2011 
root@oberon.local:/home/riastradh/netbsd/current/obj/sys/arch/i386/compile/RIAMONOHACK
 i386
Architecture: i386
Machine: i386
>Description:

        I have three tmpfses mounted, at

                /tmp (1 GB)
                /var/chroot/pbulk/2011Q3/tmp (2 GB)
                /var/chroot/pbulk/current/tmp (1 GB)

        Last night I started a bulk build chrooted in
        /var/chroot/pbulk/2011Q3.  A lot of packages started failing,
        and I noticed that `df -h' reported the tmpfses to have a size
        (not available space, but size) of 10--20 MB!  The exact size
        reported by df for each of the tmpfses varied over time between
        around ten and twenty megabytes, sometimes ten, sometimes
        fifteen, sometimes sixteen, &c.  After an hour or so, the
        tmpfses returned to their correct sizes of 1 GB or 2 GB.

>How-To-Repeat:

        Do a bulk build with wrkobjdir set to a tmpfs in a chroot,
        maybe?

>Fix:

        Yes, please!