#!/bin/bash

truncate --size 100M img
mkdir mountpoint
dd if=/dev/urandom of=file bs=1024k count=85
echo 1 > /proc/sys/vm/drop_caches

# prvni filesystem
losetup /dev/loop7 img
mkfs.ext3 /dev/loop7
mount /dev/loop7 mountpoint
cp file mountpoint/file
umount mountpoint/
blockdev --flushbufs /dev/loop7
sync
losetup -d /dev/loop7
losetup /dev/loop6 img
dd if=/dev/zero of=/dev/loop6 bs=1024k seek=30 count=30 conv=notrunc 
blockdev --flushbufs /dev/loop6
sync
losetup -d /dev/loop6
losetup /dev/loop5 img
fsck.ext3 -p /dev/loop5
mount /dev/loop5 mountpoint/ 
md5sum mountpoint/file > hash
umount mountpoint/
losetup -d /dev/loop5

# druhej filesystem
losetup /dev/loop4 img
mkfs.ext3 /dev/loop4
mount /dev/loop4 mountpoint
cp file mountpoint/file
umount mountpoint/
blockdev --flushbufs /dev/loop4
sync
losetup -d /dev/loop4
losetup /dev/loop3 img
dd if=/dev/zero of=/dev/loop3 bs=1024k seek=30 count=30 conv=notrunc 
blockdev --flushbufs /dev/loop3
sync
losetup -d /dev/loop3
losetup /dev/loop2 img
fsck.ext3 -p /dev/loop2
mount /dev/loop2 mountpoint/ 
md5sum -c hash &> vysledek
umount mountpoint/
losetup -d /dev/loop2

rm hash
rm file
rm -r mountpoint
rm img
echo 0 > /proc/sys/vm/drop_caches