extlinux: /boot on ext4, rootfs on btrfs

[Chris Murphy]

On Nov 26, 2013, at 3:16 PM, Gene Czarcinski <gczarcinski at gmail.com> wrote:
>> 
> and here is the one from the /boot on ext4 but rootfs on btrfs:
>> label Fedora (3.11.8-300.fc20.x86_64)
>>    kernel /vmlinuz-3.11.8-300.fc20.x86_64
>>    append vconsole.keymap=us vconsole.font=latarcyrheb-sun16 psmouse.proto=imps root=UUID=909a8e5a-2b60-4b76-b665-6e5167c7e4fc rhgb quiet LANG=en_US.UTF-8
>>    initrd /initramfs-3.11.8-300.fc20.x86_64.img
> 
> Look pretty much the same to me.

And that's the problem. With btrfs, anaconda needs to include the kernel param rootflags=subvol=root in order to get the kernel to know it needs to use the root subvol as rootfs. It does this for GRUB2 but for some reason isn't doing it for extlinux. So it's an anaconda bug.

I bet dollars to donuts if you add that parameter to your extlinux.conf that it will then boot.

> The error message said something about initrd-switch-root failing. Sorry, this is out of my past experience.

Yes it's imploding because it can't find rootfs.

> Again, I do not see this as any type of blocker.  It needs to get fixed but how much of this is really used?  Except for nuts like me and Chris? ;)

Not a blocker, freeze exception. If devs get the time to fix it, it'll get fixed. Might be mattdm who fixes it so I'll reproduce, propose the FE and cc Matt.


Chris Murphy