Comment 19 for bug 204133

OK, I seem to have a handle on the real problem now.

Basically the final umounts of the filesystems is probably not working correctly on shutdown/reboot causing the ext3 loopback filesystem to get corrupted.

I think what is happening is that the NTFS filesystem is being unmounted before the looped back ext3 filesystem on that NTFS filesystem and the of course the ext3 filesystem cannot be umounted correctly and then the corruption found on the next reboot.

The kernel panics we see are because of the severe corruption in the loop mounted ext3 filesystem. I've managed to reproduce this on my system in a way that happens every time, no matter what kind of vm dirty flags are being tweaked. The vm dirty flags cannot work around such an issue - I believe somebody with better knowledge of Wubi and the Ubuntu shutdown process than I needs to investigate this.

In summary: Make sure the ext loopback file systems are umounted before the NTFS filesystems.

Colin