[[Mathias Chauvin]] - IT stuff

You may have been confronted to this issue: when using Ubuntu Hoary on a USB stick in persistent mode, the casper-rw partition is not cleanly unmounted.
If this happens, the default user home folder may be corrupted. Then the profile can not be loaded.

To fix this, I’ve modified the initrd.gz, by adding the e2fsck tool to it and forcing the checking of the casper-rw partition before mounting it.

0/ Some pre-requisites
The following is based on the Ubuntu wiki.
The squashfs filesystem will be modified. To do so the squashfs-tools package is to be installed on your machine.
Extract the casper/filesystem.squashfs file from the Ubuntu Hoary iso to /mnt/hoary:

root@server:~# mkdir -p /mnt/hoary
root@server:~# cd /mnt/hoary
root@server:/mnt/hoary# unsquashfs /media/cdrom/casper/filesystem.squashfs

1/ Adding the e2fsck tool to the initrd
Edit the following file

/mnt/hoary/squashfs-root/usr/share/initramfs-tools/hooks/casper

and add these lines

# We need fsck to check the persistent casper-rw partition
copy_exec /sbin/e2fsck /sbin

Here is the patch to apply to hooks/casper.

2/ Forcing the checking of the casper-rw partition
Edit this file:

/mnt/hoary/squashfs-root/usr/share/initramfs-tools/scripts/casper

and add the following lines

    log_warning_msg "Checking the casper-rw partition ${cowdevice}"
    e2fsck -v -y ${cowdevice} || \\
      log_warning_msg "Not able to check the ${cowdevice} partition"
    log_warning_msg "Mounting the casper-rw partition"

before the

mount ${cowdevice} -t ${cow_fstype} -o rw,noatime /cow || \\
panic "Can not mount $cowdevice on /cow"

line. (See also this post)

Here is the patch to apply to the casper file.

3/ Build of the initrd.gz
chroot to the extracted squashfs filesystem. Use mkinitramfs to build the modified initrd.gz.

root@server:/mnt/hoary/squashfs-root# chroot .
root@server:/# mkinitramfs -o initrd.gz 2.6.24-16-generic

4/ Copy the initrd.gz to the USB stick

root@server:/# exit
root@server:/mnt/hoary/squashfs-root# cp initrd.gz /media/ubuntu

5/ Build the squashfs file

root@server:/mnt/hoary/squashfs-root# mksquashfs . ../filesystem.squashfs
root@server:/mnt/hoary/squashfs-root# cp ../filesystem.squashfs \\
/media/ubuntu/casper

Your USB persistent live system is now fully operational! Enjoy!