#!/bin/sh

# create an lvm snapshot volume and then e2fsck that volume
# if it's successful then we set the mount count to 0 and
# last fs check time to the timestamp of when we took the
# snapshot.
#
# example:  snapfsck /dev/foo_vg/bar_lv 1G
#
# 1G is the snapshot volume size.
#
# this code is public domain.
#
# dean gaudet <dean@arctic.org>

PATH=/usr/bin:/bin:/usr/sbin:/sbin
export PATH

if [ $# != 2 ]; then
	echo "usage: $0 lvname snapsize" 1>&2
	exit 1
fi
lvname="$1"
size="$2"

# if we're successful then we'll mark the lv as having been fsck'd
# at this time ... we need to sleep into the next second to be
# completely accurate.  tune2fs -T expects local time.
now="`date +%Y%m%d%H%M%S`"
sleep 1

snapname=snapfsck$now
lvcreate --size "$size" --snapshot --name $snapname "$lvname" || exit 1
snapname="`dirname $lvname`/$snapname"

if e2fsck -f -n "$snapname"; then
	tune2fs -C 0 -T $now "$lvname"
fi
rc=$?

lvremove -f "$snapname"

exit $rc