Re: [gentoo-user] Using "root=LABEL=xxxx" in grub.conf

[Dale <rdalek1967@gmail.com>]

Stroller wrote:
> Hi there,
>
> Is anyone using "root=LABEL=xxxx" grub.conf, please? Anyone also using
> ext4 for their root?
>
> I can find numerous references to this syntax going back to 2005 or
> so, and some major distros seem to use it as the default way of
> describing "root=" to the kernel.
>
> http://www.linuxforums.org/forum/redhat-fedora-linux-help/23010-root-label-grub-conf.html
>
> http://linux.derkeiler.com/Mailing-Lists/RedHat/2005-01/0026.html
>
> But it doesn't work for me. :(
>
> Here's a working configuration:
>
>     stroller@hex ~ $ cat /etc/fstab
>     # /etc/fstab: static file system information.
>     #
>     # <fs>            <mountpoint>    <type>        <opts>       
> <dump/pass>
>     
>     # NOTE: If your BOOT partition is ReiserFS, add the notail option
> to opts.
>     LABEL=boot        /boot        ext2        noauto,noatime    1 2
>     LABEL=root        /        ext4        noatime        0 1
>     LABEL=swap        none        swap        sw        0 0
>     /dev/cdrom        /mnt/cdrom    auto        noauto,ro    0 0
>     
>     # glibc 2.2 and above expects tmpfs to be mounted at /dev/shm for
>     # POSIX shared memory (shm_open, shm_unlink).
>     # (tmpfs is a dynamically expandable/shrinkable ramdisk, and will
>     #  use almost no memory if not populated with files)
>     shm            /dev/shm    tmpfs        nodev,nosuid,noexec    0 0
>     
>     stroller@hex ~ $ sudo mount -v -L boot
>     /dev/sda1 on /boot type ext2 (rw,noatime)
>     stroller@hex ~ $ cat /boot/grub/grub.conf
>     default 0
>     timeout 30
>     splashimage=(hd0,0)/boot/grub/splash.xpm.gz
>     
>     title Gentoo Linux 2.6.28-gentoo-r1
>     root (hd0,0)
>     kernel /boot/bzImage-2.6.28-gentoo-r1 root=/dev/sda6
>     
>     stroller@hex ~ $
>
>
> If I simply change the kernel line of grub.conf to:
>
>     kernel /boot/bzImage-2.6.28-gentoo-r1 root=LABEL=root
>
> Then I get a kernel panic upon boot:
>    VFS: Cannot open root device "LABEL=root" or unknown-block(0,0)
>    Please append a correct "root=" boot option; here are the available
> partitions:
>    ...
>    Kernel Panic - not syncing: VFS Unable to mount root fs on
> unknown-block(0,0)
>
> Full screenshot of kernel panic:
>    http://stuff.stroller.uk.eu.org/KernelPanic.png
>
>
> Googling this error brings up quite a number of hits, and I reckon I
> must have spent a couple of hours now trying the most popular
> resolutions. This is quite a minor error - if I wasn't such an
> obsessive-compulsive I could easily ignore it, but I am, and it's
> frustrating the heck out of me.
>
> One forum thread / bug report suggests the ata_piix module is to
> blame, but compiling that statically into my kernel doesn't help.
> http://www.linuxquestions.org/questions/fedora-35/fc2-vfs-cannot-open-root-device-label-or-unknown-block00-269230/
>
> https://bugzilla.redhat.com/show_bug.cgi?id=126953
>
> Another post (can't find the reference now) suggests disabling
> "Initial RAM filesystem and RAM disk (initramfs/initrd) support" but
> that doesn't make any difference, either.
>
> Finally, this thread <http://kerneltrap.org/node/2318> says "check
> your .config and look for CONFIG_BLK_DEV_IDE and
> CONFIG_BLK_DEV_IDEDISK entries." This is quite an old post, however,
> and these options aren't available in 2.6.28 (from my distro); I
> enabled CONFIG_BLK_DEV_IDEPCI instead, but it has no positive effect.
>
> I had better mention that I am using a 3ware 9500 RAID controller on
> the PCI bus. I suspect the problem is specific to this (and my
> combination of modules / compiled-in kernel drivers), but I thought I
> would throw the question out there & see if any other ext4 users had
> also seen the same thing.
>
> Thanks in advance for any suggestions,
>
> Stroller.
>
>
>

You may have done this but just in case, you did use the tools to set
the label on the drive right?  tune2fs does it for ext2 and ext3.  I'm
not sure about ext4. 

I only mention this cause this sounds like something I would do. 

Dale

:-)  :-)