sudo touch /forcefsck
The following command converts the filesystem to EXT3, by creating the necessary journal.
tune2fs -c 0 -i 30 -j /dev/sda1
Edit /etc/fstab replacing ext2 with ext3 for the root filesystem mount.
Next we need to rebuild the Linux boot image using the mkinitrd tool.
Unrolling the Change
If it goes wrong, and you need to convert back to EXT2, your best bet is to do it unmounted. In other words, boot into a different OS installed elsewhere. The simple choice is a Linux Live CD for pretty much any distro.
umount /dev/sda1
tune2fs -O ^has_journal /dev/sda1
e2fsck /dev/sda1
Edit /etc/fstab to change /dev/sda1 to mount as ext2
mount /dev/sda1
