File systems clean after crash?

[Oliver Fromme]

Hi,

Yesterday a machine of mine crashed because of a bad power
supply (not FreeBSD's fault); its running 6.2-PRERELEASE
as of 2006-09-20.  I've disabled background fsck in rc.conf.
So, when rebooting I expected it to report all filesystems
to be unclean and run fsck on them.

Instead, three filesystems were reported as being clean
(the root FS, /var and /usr), and only the forth one
(/home) was actually fsck'ed.

Now I wonder why three of the file systems were reported as
being clean.  It's my understanding that file systems are
only marked clean when they're unmounted.  Did that change
recently?  The system was idle at the time of the crash,
and soft-updates was enabled, so it's possible that there
weren't any write accesses to the file systems within some
time frame (a few minutes, I guess).  Does the UFS code
mark a mounted file system as clean if there wasn't any
write operation for a certain time?

Best regards
   Oliver

PS:  I'm paranoid, so I rebooted again into single-user
mode and forced fsck on all file systems, just to be sure.
Everything seems to be OK.

-- 
Oliver Fromme,  secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd
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