Re: [Ext2-devel] [RFC 0/13] extents and 48bit ext3

Pavel Machek
2006-06-15T09:51:11Z

Hi!

> >> >Passes 8 hours of me trying to intentionally break it with weird,
> >> >artifical disk corruption.
> >> >
> >> >I even have script somewhere.
> >>
> >> Ok, thanks for clarifying.
> >
> >You can get a copy, it would be interesting to know how JFS/XFS does.
>
> Ok, I would be interested in getting a copy. (Maybe it would be good
> to post it in public so that other people can try it too.)

It needs some hand-tuning to do maximum damage to the filesystem, yet
keeping filesystem "recognizable". It also depends on fsck returning
reasonable error codes...
Pavel

#!/bin/bash
#
# fscktest
#
# Usage:
# Make sure output is logged somewhere
# First, run fscktest -p as root
# Then you can run fscktest as normal user...
#

prepare() {
SIZE=100000
echo "Creating file..."
cat /dev/zero | head -c $[$SIZE*1024] > test
echo "Making filesystem..."
mkfs.$FS test
echo "Mounting..."
mount test -o loop /mnt || exit "Cant mount"
echo "Copying files..."
cp -a /bin /mnt
cp -a /usr/bin /mnt
cp -a /usr/src/linux /mnt
echo "Syncing..."
sync
echo "Unmounting..."
umount /mnt
echo "Moving..."
mv test fsck.okay
echo "All done."
}

FS=ext2
if [ .$1 == .-p ]; then
prepare
exit
fi
RUN=0
while true; do
RUN=$[$RUN+1]
echo "Run #$RUN"
echo Preparing...
cat fsck.okay > fsck.damaged
echo Damaging...
dd if=/dev/urandom of=fsck.damaged count=10240 seek=7 conv=notrunc
cp fsck.damaged fsck.test
echo First check...
fsck.$FS -fy fsck.damaged
RESULT=$?
if [ $RESULT != 1 -a $RESULT != 2 -a $RESULT != 0 ]; then
echo "Fsck failed in bad way (result = $RESULT)"
exit
fi
echo Second check...
fsck.$FS -fy fsck.damaged
RESULT=$?
if [ $RESULT != 0 ]; then
echo "Fsck lied about its success (result = $RESULT)"
exit
fi
done

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html