More on the blkfree panic

[Don Lewis]

On  2 May, Joe Marcus Clarke wrote:
> This panic started happening to me after I cvsup'd and rebuilt
> yesterday.  Prior to that I never had the problem with a -CURRENT from
> 04/26 (using the same steps listed below).  Now I can reliably reproduce
> the crash on:
> 
> FreeBSD bulgogi.cisco.com 5.0-CURRENT FreeBSD 5.0-CURRENT #2: Fri May 2
> 14:08:06 EDT 2003   
> marcus at bulgogi.cisco.com:/usr/obj/usr/src/sys/BULGOGI  i386

I haven't seen it on my 4/26 machine, though I haven't done anything
disc intensive (other than the daily cron jobs) since then. The reports
of this problem started showing up on 4/27, so I went hunting for
commits during the likely window using cvs diff.  There were a number of
vm locking changes made during that time, including some changes to
vfs_bio.c.  That's about as close as anything came to touching the
filesystem code.