Re: After crash, / comes up mounted read-only, but in multiuser; mfs /tmp?

From: John Baldwin <jhb_at_freebsd.org>
Date: Fri, 2 Dec 2005 08:40:55 -0500
On Friday 02 December 2005 08:33 am, David Xu wrote:
> Robert Watson wrote:
> > While testing the new DRM update (went badly :-), I crashed my system
> > and had to power cycle it.  When it came back up, not surprisingly,
> > the file systems weren't clean.  When I reached a login prompt, I
> > logged in to modify /etc/rc.conf, and to my surprise, was told that
> > /etc/rc.conf wasn't writable.  Turns out it was because / was mounted
> > read-only:
> >
> > ad0: 57231MB <HTS541060G9SA00 MB3IC60H> at ata0-master SATA150
> > acd0: CDRW <HL-DT-STCD-RW/DVD DRIVE GCC-4246N/0X05> at ata1-master UDMA33
> > Trying to mount root from ufs:/dev/ad0s3a
> > WARNING: / was not properly dismounted
> > Loading configuration files.
> > kernel dumps on /dev/ad0s3b
> > Entropy harvesting: interrupts ethernet point_to_point kickstart.
> > swapon: adding /dev/ad0s3b as swap device
> > Starting file system checks:
> > /dev/ad0s3a: INCORRECT BLOCK COUNT I=16528 (4 should be 0) (CORRECTED)
> > /dev/ad0s3a: UNREF FILE I=16528  OWNER=root MODE=100444
> > /dev/ad0s3a: SIZE=0 MTIME=Dec  2 10:33 2005  (CLEARED)
> > /dev/ad0s3a: FREE BLK COUNT(S) WRONG IN SUPERBLK (SALVAGED)
> > /dev/ad0s3a: SUMMARY INFORMATION BAD (SALVAGED)
> > /dev/ad0s3a: BLK(S) MISSING IN BIT MAPS (SALVAGED)
> > /dev/ad0s3a: 2378 files, 78670 used, 175145 free (441 frags, 21838
> > blocks, 0.2%
> > fragmentation)
> > /dev/ad0s3e: DEFER FOR BACKGROUND CHECKING
> > /dev/ad0s3d: DEFER FOR BACKGROUND CHECKING
> > WARNING: /usr was not properly dismounted
> > WARNING: /var was not properly dismounted
> > /var: mount pending error: blocks 4 files 1
> > Setting hostname: sesame.cam.watson.org.
> > bge0: link state changed to DOWN
> > bge0: no link ....bge0: link state changed to UP
> >
> > ...
> >
> > /dev/ad0s3a on / (ufs, local, read-only)
> > devfs on /dev (devfs, local)
> > /dev/ad0s3e on /usr (ufs, local, soft-updates)
> > /dev/ad0s3d on /var (ufs, local, soft-updates)
> > /dev/md0 on /tmp (ufs, local)
> >
> > The rc scripts helpfully mounted an MFS /tmp for me, which while
> > friendly, succeeded in masking the problem and allowing the system to
> > come up in a rather undesirable state (from my perspective).  So it
> > sounds like maybe / wasn't remounted properly, and then the scripts
> > were too helpful thinking it was a diskless system.
> >
> > Robert N M Watson
>
> I have seen this for some days,  one machine I even have to reinstall
> the system because mount -u / does not work. :-(

I've seen reports that mount -u -w / works whereas mount -u -o rw / doesn't, 
so you might be able to mount -u -w / in single user mode after running fsck 
as a way to recover.  Either that or boot single user, run fsck, and then 
reboot before going into multiuser.

-- 
John Baldwin <jhb_at_FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org
Received on Fri Dec 02 2005 - 12:42:25 UTC

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