>Number:         761
>Category:       kern
>Synopsis:       union mounts in -current ate my kernel build tree
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jan 28 15:05:02 1995
>Originator:     John Kohl
>Organization:
NetBSD Kernel Hackers `R` Us
>Release:        1.0A
>Environment:
	
System: NetBSD kolvir 1.0A NetBSD 1.0A (KOLVIR) #4: Sat Jan 28 16:42:05 EST 1995 jtk@kolvir:/u1/NetBSD-current/src/sys/arch/i386/compile/KOLVIR i386


>Description:
I have the following regular and union mounts set up:
	/dev/sd0f /u1 ufs rw 1 2
	/dev/wd0e /u2 ufs rw 1 2
	/u2 /u1/NetBSD-current union rw,noauto,-b 1 2

I was doing some work today on freshly-SUPed i386 kernel source, and at
some point my build tree (all the .o's) in
/u1/NetBSD-current/sys/arch/i386/compile/KOLVIR just vanished.  I suspect it
happened at the time of running config.new to update the configuration.
Running fsck revealed they'd all been abandoned--it cheerily attached
them all to /u1/lost+found.

This happened earlier today, but I chalked that up to an older union FS
type (I was in the middle of updating to the latest stuff).  I tried
running config.new again after I lost the tree the 2nd time and
rebooted, but I couldn't cause more files to vanish by running
config.new.

>How-To-Repeat:

Not quite sure how to reliably repeat this--I'm not anxious to lose
another kernel build tree.  Maybe it has something to do with working on
the filesystem without the union mount mounted, and then mounting the
union later?

>Fix:
	
>Audit-Trail:
>Unformatted: