Comment 3 for bug 1644975

I can confirm that the following statement in https://help.ubuntu.com/community/SwapFaq#Why_do_I_need_swap.3F is wrong:

> The hibernation implementation currently used in Ubuntu, swsusp, needs a swap or suspend partition. It cannot use a swap file on an active file system.

In fact, swsusp supports offsets just fine, and so does initramfs-tools - mostly. The only thing blocking hibernation to a swap file from working is that check in /usr/share/initramfs-tools/scripts/local-premount/resume script. It calls wait-for-root which returns "ext4" because no offset has been passed in. So the script will just assume that no hibernation occurred and continue without resuming. While I opted for simply removing the check, I strongly suspect that Ryo's patch will fix the issue just as well.