root fs on usb - is patching kernel still needed?

root fs on usb - is patching kernel still needed?

[Tomasz Chmielewski]

Hello,

I've been trying to boot Linux from an root fs which is on an usb-stick 
(kernel is on a bootdisk floppy).

Unfortunately, the kernel seems to try to mount the filesystem which is 
on an usb-stick too fast, before usb shows up for the kernel.

While reading this list I found several patches solving this problem, 
which wait a bit before root fs is mounted, which re-try in a loop to 
mount root fs etc.


Are there any solutions for this problem in stable or pre- kernel tree 
yet (2.4 or 2.6)? If not, will such a solution be ever included in a 
stable kernel?

Or maybe are there any easier solutions for this (some lilo or grub option?)


Regards,

Tomasz Chmielewski

Re: root fs on usb - is patching kernel still needed?

[Willy Tarreau]

Hi,

On Sun, May 16, 2004 at 09:15:08PM +0200, Tomasz Chmielewski wrote:
> Are there any solutions for this problem in stable or pre- kernel tree 
> yet (2.4 or 2.6)? If not, will such a solution be ever included in a 
> stable kernel?

AFAICT, none has been merged (yet).

> Or maybe are there any easier solutions for this (some lilo or grub 
> option?)

An initrd might do the trick, although it's sometimes unconvenient to use :
- lilo (or grub) loads the initrd into memory
- lilo (or grub) loads the kernel and executes it
- the kernel sees the initrd and mounts it and executes /linuxrc
- linuxrc can load USB modules and wait the required amount of time
- linuxrc then mounts the root fs and does the pivot_root() and exits
- the kernel finally boots /sbin/init from your USB FS.

Regards,
Willy