kernel 2.6.17-gentoo-r8

[o_O]

Like, hi.

I have upgraded to the above kernel, but it's not being cool.

Everything was working fine on 2.6.15, except it didn't like my card reader, which is fixed in 2.6.17, so that's my reason for upgrading.

The actual problem is that the kernel can't mount my root partition (/dev/sda4), so it gives me a error:
Block device /dev/sda4 is not a valid root device
and then asks me to specify a root device.

For some reason, the drive mapping seems to have shifted along; I have two SATA hard drives in my box and what was previously /dev/sda is now /dev/sdb, etc.
I'm pretty sure it either has something to do with my grub.conf or SCSI support. I have tried compiling support for SCSI into the kernel and using modules. With both, if I try booting using /dev/sdb, it boots until it comes to mounting the partition /dev/sdb4, and then tells me
"Could not fix filesystem :("
and I can either get into a shell for maintenance or reboot.
It appears to successfully load my SCSI modules though.

I'm booting from Grub using the following kernel section

title=Gentoo Linux (2.6.17-gentoo-r8)
root(hd0,2)
kernel /boot/kernel-genkernel-x86_64-2.6.17-gentoo-r8 root=/dev/ram0 init=linuxrc ramdisk=8192 real_root=/dev/sda4 udev video=vesafb:ywrap,mtrr vga=0x31B splash=silent,theme=emergence CONSOLE=/dev/tty1
initrd (hd0,1)/boot/initramfs-genkernel-x86_64-2.6.17-gentoo-r8

It's a bit of a long shot, but any ideas? I've had a bit of a search for similar problems, but nothing seems to have fixed it.

[Endless]

Did you try physically swapping your two sata drives? What partition type are you using? What does fdisk (fdisk /dev/sda and fdisk /dev/sdb) say when you do it from the maintenance line?

[o_O]

Hmm, I managed to get the new kernel booting. It seems that it was a combination of my fstab still trying to boot my old configuration, my grub trying to boot using real_root=/dev/sda4 and mainly, for <i>some</i> reason, the kernel ignored my config file and didn't compile support for ReiserFS.

Now I'm trying to get it to recognise all of my old modules.

Thanks anyway though, dmesging from the maintenance line was exactly what told me what the problem was. :)

[Dr Unne]

I think udev is meant to solve the problem of device nodes being assigned to devices in random order; udev identifies devices using some hardware ID and makes sure the same node goes to the same device each time. But udev is not fun to play with.

[o_O]

Yeah, I had a bit of a play with udev too. I tried changing the order in which it came in grub.conf, and also recompiling explicitly using udev, but (apparently) it's already enabled by default.

Not to mention I'm not at all familiar with the ins and outs of udev anyway, so I'm not sure what I could have done.