Dual boot Fedora Ubuntu

[garaden]

On my first day at work I used a Fedora Live CD to resize an existing Ubuntu partition but can no longer boot into it (Fedora works fine, though). After reading about Fedora's inability to recognize other GNU/Linux installations, I tried to find the necessary information to enter into grub, but I can't even mount the partition anymore!

Incidentally, neither can grub: after trying to guess at a few paths based on the other machines in the office, grub just spits out a "can't mount the volume" error. Trying to enter "rootnoverify" and "chainloader +1" yielded a "bad executable" error. Why can't anything use this partition anymore? I'm tempted to just hunt down an Ubuntu Live CD and try using that to recover the partition, but I have no idea what that would do to Fedora's grub configuration.

Here's "fdisk -lu":

Disk /dev/sda: 250.0 GB, 250000000000 bytes
255 heads, 63 sectors/track, 30394 cylinders, total 488281250 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0xa42d04a3

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *          63   204800062   102400000   83  Linux
/dev/sda2       476343315   488279609     5968147+   5  Extended
/dev/sda3       204812685   205214309      200812+  83  Linux
/dev/sda4       205214310   476343314   135564502+  8e  Linux LVM
/dev/sda5       476343378   488279609     5968116   82  Linux swap / Solaris

Partition table entries are not in disk order

As far as I can tell, sda1 is the Ubuntu partition, sda3 is Fedora's /boot partition, sda4 is the rest of Fedora and sda5 is the swap partition (I don't know if Fedora or Ubuntu put that there). I'm also not sure what sda2 is. It's not critical that I recover the partition, but it'd be nice. Any ideas?

[yancek]

Boot into Fedora and create a mount point for Ubuntu as root.

mkdir /mnt/ubuntu

As root, mount ubuntu: mount -t ext3 /dev/sda1 /mnt/ubuntu

(this is assuming ext3 filesystem and ubuntu on sda1?)

List directories for Ubuntu: ls -l /mnt/ubuntu/
You should see the files there. If you do, then navigate to the /boot/grub/menu.lst file to get the Ubuntu entry and copy to the Fedora menu.lst file (done as root).

[garaden]

That's where I ran into trouble before... trying to mount sda1 yields:

mount: wrong fs type, bad option, bad superblock on /dev/sda1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

Here's the dmesg | tail output:

JBD: IO error reading journal superblock
EXT3-fs: error loading journal.
attempt to access beyond end of device
sda1: rw=0, want=237768728, limit=204800000
JBD: IO error reading journal superblock
EXT3-fs: error loading journal.
attempt to access beyond end of device
sda1: rw=0, want=237768728, limit=204800000
JBD: IO error reading journal superblock
EXT3-fs: error loading journal.

I can't make much sense of it, but I suspect the "want" being greater than the "limit" is a serious problem.

[reed9]

I've never used it, but I believe Super Grub Disk will allow you to fix this fairly easily.

Super Grub Disk Homepage

Super GRUB Disk--A GRUB Repair Utility

[garaden]

I'll give it a shot tomorrow after I bring in a USB drive, but I suspect grub's not the real problem since I can't even mount the partition. Unless Super Grub Disk can fix other things in the master boot record besides grub... isn't that where partition information is stored?

[yancek]

The error you get "wrong fs type, bad option, bad superblock on /dev/sda1" may be the wrong filesystem. I assumed ext3 as the filesystem but don't know if that is correct?? Check to see whether ext3 is the correct filesystem for your version of Ubuntu?

In you first post you stated you did not know what sda2 is, it's an Extended Partition which is a placeholder for your logical partitions and can hold no data.

attempt to access beyond end of device
sda1: rw=0, want=237768728, limit=204800000

I agree the above could be part of the problem. Your fdisk -l output in your first post hows the "204800000" for sda1. Not sure what that means as I've never used LVM and don't know if that has anything to do with it.

[garaden]

Wow, Super Grub Disk is indeed super! Using it I was able to not only read the Ubuntu menu.lst file, but I was able to load the kernel. Unfortunately, things went downhill from there... as soon as it got to the "root=" argument, it was unable to load /sbin/init: "mount" claimed that the UUID it was trying to mount was an invalid argument. After this the kernel went to a console without mounting anything. But at least I had the paths I wanted!

Noting the kernel and initrd image, I edited Fedora's grub.conf with the Ubuntu information. Same problem (mount claims "invalid argument"), even replacing "root=" with "/dev/sda1" instead of whatever that UUID was. Also, while trying "/dev/hda1" grub asserted (correctly) that hda1 doesn't exist, so I think the UUID is still correct (Wikipedia says there's no reason they should change since they're stored in the partition).

So just to clarify, the Ubuntu kernel was able to load and then failed upon reaching "mount /dev/sda1 /root". Which means we're back to square one. What on earth happened to this volume?

fsck seemed the logical next step, since the partition is expendable. Unfortunately, I got all kinds of messes from that. Here's the code:

sudo e2fsck /dev/sda1
Superblock has an invalid journal (inode 8).
Clear? yes

*** ext3 journal has been deleted - filesystem is now ext2 only ***

The filesystem size (according to the superblock) is 59542906 blocks
The physical size of the device is 25600000 blocks
Either the superblock or the partition table is likely to be corrupt!
Abort? yes

Since the physical size goes to 100 megs (the partition size I chose for the Ubuntu partition during the Fedora install) if I assume a block size of 4K (incidentally, it looks like the Fedora partition uses 1K block sizes judging from the fdisk output, confusing matters further), I'm going to side with the partition table on this one and assume the superblock is the culprit.

Unfortunately, the backup superblock at "e2fsck -n -b 32768 /dev/sda1" was screwed too, but I didn't want to clear it in case there was something else we could do. Here's the results:

Superblock has an invalid journal (inode 8).
Clear? no

e2fsck: Illegal inode number while checking ext3 journal for /dev/sda1

Looks to me like the Ubuntu filesystem wasn't informed about the partition resize. If I'm lucky, we can somehow reconfigure the superblocks. If I'm unlucky, my shiny new Fedora partition just steamrollered half the Ubuntu partition's data. Which would actually be kind of amusing... I knew Fedora didn't play nice with other distros, but geez... :P Any thoughts?