Date: Mon, 22 Dec 1997 10:40:02 -0800 (PST) From: Cy Schubert - ITSD Open Systems Group <cschuber@uumail.gov.bc.ca> To: freebsd-bugs Subject: Re: kern/5355: Fix for NULLFS problems Message-ID: <199712221840.KAA14709@hub.freebsd.org>
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The following reply was made to PR kern/5355; it has been noted by GNATS.
From: Cy Schubert - ITSD Open Systems Group <cschuber@uumail.gov.bc.ca>
To: Bruce Evans <bde@zeta.org.au>
Cc: cschuber@uumail.gov.bc.ca, freebsd-gnats-submit@freebsd.org,
cy@passer.osg.gov.bc.ca
Subject: Re: kern/5355: Fix for NULLFS problems
Date: Mon, 22 Dec 1997 10:35:40 -0800
I'll give your code a try.
Would it be a good idea to to have a panic() or a printf() where I return a
FALSE? I'm torn between providing better diagnostic messages and reducing
kernel bloat. By doing a printf() or panic() any author of a filesystem would
know that he would need to do some work on his code.
Regards, Phone: (250)387-8437
Cy Schubert Fax: (250)387-5766
UNIX Support OV/VM: BCSC02(CSCHUBER)
ITSD BITNET: CSCHUBER@BCSC02.BITNET
Government of BC Internet: cschuber@uumail.gov.bc.ca
Cy.Schubert@gems8.gov.bc.ca
"Quit spooling around, JES do it."
> >>Fix:
> >cwsys# cat /opt/archives-3/usermods/nullfs_panic_fix.usermod
> >--- src/sys/vm/vnode_pager.c.orig2 Sun Dec 7 13:11:03 1997
> >+++ src/sys/vm/vnode_pager.c Fri Dec 19 06:30:27 1997
> >@@ -231,10 +231,12 @@
> > blocksperpage = 0;
> > if (pagesperblock > 0) {
> > reqblock = pindex / pagesperblock;
> >- } else {
> >+ } else if (bsize > 0) {
> > blocksperpage = (PAGE_SIZE / bsize);
> > reqblock = pindex * blocksperpage;
> >- }
> >+ } else
> >+ return FALSE;
> >+
>
> I think bsize is supposed to be > 0 here. Lots of other places depend
> on vp->v_mount->mnt_stat.f_iosize being reasonable. nullfs and some
> other file systems (portal and umapfs at least) just don't initialize
> most of mnt_stat (except by bzeroing it). This untested fix for nullfs
> was obtained from union[fs].
>
> diff -c2 null_vfsops.c~ null_vfsops.c
> *** null_vfsops.c~ Mon Oct 13 21:46:00 1997
> --- null_vfsops.c Mon Dec 22 04:32:11 1997
> ***************
> *** 199,202 ****
> --- 199,203 ----
> &size);
> bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
> + (void)nullfs_statfs(mp, &mp->mnt_stat, p);
> #ifdef NULLFS_DIAGNOSTIC
> printf("nullfs_mount: lower %s, alias at %s\n",
>
> Bruce
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