Date: Thu, 7 Nov 1996 12:54:35 -0500 (EST) From: Thomas David Rivers <ponds!rivers@dg-rtp.dg.com> To: michaelh@cet.co.jp, ponds!Root.COM!dg@ucbvax.Berkeley.EDU Cc: ponds!freefall.freebsd.org!freebsd-hackers@ucbvax.Berkeley.EDU, ponds!ponds!rivers@ucbvax.Berkeley.EDU Subject: Re: More info on the daily panics... Message-ID: <199611071754.MAA03193@lakes.water.net>
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>
> > In the one case of this problem that I looked into, it was caused by the
> > v_usecount being negative. There was clearly one too many vrele's occuring
> > somewhere. It was not caused by any sort of "freelist wrap" condition. The
> > patch you've provided will kludge around the problem, but it is not in any
> > sense a "fix". Each time a vnode is deallocated too many times (and thus
> > v_usecount goes negative), you'll end up losing all of the vnodes on the
> > freelist that follow it (potentially several thousand) because the condition
> > will never go away. This is bad.
>
> Then Thomas would be doing us a favor if he put in the following diff to
> help track it down:
>
Ask and ye shall receive....
I think the original patch was in reverse order; here's what I've
done relative to 2.1.5-STABLE.
By the way, it's Dave, not Thomas... It's a southern idiocyncratic
'feature' to use your middle-name as your familiar title, not your
first. So, why don't I do that in the GECOS field of my passwd
entry?... well, that's an entirely different issue, involving my
father, his father and some issues with the banking establishment.. :-) :-)
- Dave R. -
*** vfs_subr.c.ori Thu Nov 7 12:46:24 1996
--- vfs_subr.c Thu Nov 7 12:49:24 1996
***************
*** 828,839 ****
vp->v_usecount--;
if (vp->v_usecount > 0)
return;
- #ifdef DIAGNOSTIC
if (vp->v_usecount != 0 /* || vp->v_writecount != 0 */ ) {
vprint("vrele: bad ref count", vp);
panic("vrele: ref cnt");
}
- #endif
if (vp->v_flag & VAGE) {
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
vp->v_flag &= ~VAGE;
--- 828,839 ----
vp->v_usecount--;
if (vp->v_usecount > 0)
return;
if (vp->v_usecount != 0 /* || vp->v_writecount != 0 */ ) {
+ #ifdef DIAGNOSTIC
vprint("vrele: bad ref count", vp);
+ #endif
panic("vrele: ref cnt");
}
if (vp->v_flag & VAGE) {
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
vp->v_flag &= ~VAGE;
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