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Date: Thu, 28 Nov 1996 02:42:15 +0200
Message-Id: <199611280042.AA220241735@layout.vlsi.fi>
From: Ville Eerola <ville@vlsi.fi>
To: Joe Greco <jgreco@brasil.moneng.mei.com>
Cc: hackers@freebsd.org
Subject: Re: Strange behaviour of a box.
In-Reply-To: <199611271540.JAA19169@brasil.moneng.mei.com>
References: <199611271540.JAA19169@brasil.moneng.mei.com>
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Joe Greco writes:
> I have a box that is doing something quite strange.
[...]
> [...]
> Changing root device to sd0a
> WARNING: / was not properly dismounted.
> 
> Automatic reboot in progress...
> /dev/rsd0a: CLEAN FLAG NOT SET IN SUPERBLOCK (FIXED)
> /dev/rsd0a: 1612 files, 8481 used, 6622 free (26 frags, 1649 blocks, 0.2% fragmentation)
> 
> syncing disks... done
> Rebooting...

Hmmm... If I remember correctly, it has been usual that an Unix box
will reboot immediately after fsck:ing the root partition (/dev/rsd0a)
if it was modified by the fsck. Looking through /etc/rc one finds:

= [...]
= if [ $1x = autobootx ]
= then
= 	echo Automatic reboot in progress...
= 	fsck -p
= 	case $? in
= 	0)
= 		;;
= 	2)
= 		exit 1
= 		;;
= 	4)
= 		reboot
		^^^^^^
= 		echo "reboot failed... help!"
= 		exit 1
= 		;;
= [...]

And in /usr/src/sbin/fsck/main.c:
		/*
		 * We modified the root.  Do a mount update on
		 * it, unless it is read-write, so we can continue.
		 */
		if (statfs("/", &stfs_buf) == 0) {
[...]
		}
		if (!preen)
			printf("\n***** REBOOT NOW *****\n");
		sync();
		return (4);

So I think that this explains your extra reboots...
On the other hand I haven't noticed this behaviour very often when my
box was rebooted spontaneously. Not that it is a common occurance :-)


Regards, Ville

-- 
Ville.Eerola@vlsi.fi	VLSI Solution Oy
Tel:+358 3 3165579 	Hermiankatu 6-8 C
Fax:+358 3 3165220	FIN-33720 Tampere, Finland