Subject: Re: kern/14382: softdep does not fulfill its integrity guarantees
To: Chuck Silvers <chuq@chuq.com>
From: Manuel Bouyer <bouyer@antioche.eu.org>
List: netbsd-bugs
Date: 10/29/2001 21:40:56
On Sun, Oct 28, 2001 at 08:24:18AM -0800, Chuck Silvers wrote:
> 
> >Number:         14382
> >Category:       kern
> >Synopsis:       softdep does not fulfill its integrity guarantees
> >Confidential:   no
> >Severity:       critical
> >Priority:       high
> >Responsible:    kern-bug-people
> >State:          open
> >Class:          sw-bug
> >Submitter-Id:   net
> >Arrival-Date:   Sun Oct 28 08:25:00 PST 2001
> >Closed-Date:
> >Last-Modified:
> >Originator:     Chuck Silvers
> >Release:        Sat Oct 27 08:15:30 PST 2001
> >Organization:
> me
> >Environment:
> System: NetBSD spathi.chuq.com 1.5Y NetBSD 1.5Y (SPATHI) #2: Sun Sep 30 00:40:19 PDT 2001 chs@spathi.chuq.com:/home/chs/netbsd/src/ubc.spathi/sys/arch/i386/compile/SPATHI i386
> 
> 
> >Description:
> 
> 	softdep claims to order disk writes such that the data on disk
> 	is always "safe", ie. that there are never any references to
> 	unallocated or uninitialized data.  yesterday after a crash,
> 	the normal boot-time fsck of a filesystem which had been mounted
> 	with softdep failed, and "fsck -y" said:
> 
> ** /dev/rwd0g
> ** Last Mounted on /build
> ** Phase 1 - Check Blocks and Sizes
> ** Phase 2 - Check Pathnames
> UNALLOCATED  I=230249  OWNER=root MODE=0
> SIZE=0 MTIME=Oct 28 01:00 2001 
> NAME=/obj/build/src/lib/libc/__fts13.so.o
> 
> REMOVE? yes
> 
> UNALLOCATED  I=230318  OWNER=root MODE=0
> SIZE=0 MTIME=Oct 28 01:00 2001 
> NAME=/obj/build/src/lib/libc/fts.o.o
> 
> REMOVE? yes
> 
> UNALLOCATED  I=230450  OWNER=root MODE=0
> SIZE=0 MTIME=Oct 28 01:00 2001 
> NAME=/obj/build/src/lib/libc/fmtmsg.o.o
> 
> REMOVE? yes
> 
> UNALLOCATED  I=230439  OWNER=root MODE=0
> SIZE=0 MTIME=Oct 28 01:00 2001 
> NAME=/obj/build/src/lib/libc/execvp.po.o
> 
> REMOVE? yes
> 
> UNALLOCATED  I=230442  OWNER=root MODE=0
> SIZE=0 MTIME=Oct 28 01:00 2001 
> NAME=/obj/build/src/lib/libc/fmtmsg.po.o
> 
> REMOVE? yes
> 
> UNALLOCATED  I=230444  OWNER=root MODE=0
> SIZE=0 MTIME=Oct 28 01:00 2001 
> NAME=/obj/build/src/lib/libc/execvp.so.o
> 
> REMOVE? yes
> 
> 
> 
> since this kind of corruption is never supposed to occur when softdep is used,
> softdep is clearly not delivering on its promise.

What disk system do you have ? This can also be caused by a write back cache
inside the disk.

--
Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
--