Re: umount failure

Robert Nichols (rnichols@interaccess.com)
Wed, 20 May 98 09:26 CDT

On 19 May 1998,
Stefan Monnier <monnier+lists/linux/kernel/news/@TEQUILA.SYSTEMSZ.CS.YALE.EDU>
wrote:
>
>Every once in a while, umount fails during the shutdown (probably because of
>some rogue program that the shutdown scripts didn't kill properly), forcing an
>annoying fsck at boot.
>
>Shouldn't it be possible to do a forced umount (at worst a forced
>"mount -o remount,ro") during shutdown ?

I used to do a "mount -o remount,ro" during shutdown, but I found that
it just hides the problem. The file system will be marked "clean" but
can still have problems if there were unkillable processes that had
unlinked files held open. To demonstrate this, try something like:

# cp /etc/profile /tmp/junkfile
# mt retension </tmp/junkfile #an unkillable process
# rm /tmp/junkfile
# mount -o remount,ro /tmp #my /tmp is on its own filesystem
# shutdown -r now

On my system (old and crufty 1.2.13) the file system appears clean at
reboot, but "e2fsck -f" reveals minor problems somewhat like what would
have been there without the remount.

-- 
Bob Nichols         rnichols@interaccess.com
Finger rnichols@cluster.interaccess.com for PGP public key.


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