[Clfs-support] Can't mount root at boot

[Arnie Stender]

Arnie Stender wrote:
> Bauke Jan Douma wrote:
>   
>> Hi,
>>
>> These look to be alright at first glance.
>>
>> The problem is however still that you say you have made the rootfs
>> with mke2fs, that you have it tagged as ext2 in /etc/fstab, but that
>> the kernel reports a JFS error.
>>
>> These JFS errors btw. are to be found in <linuxhome>/fs/jfs/jfs_mount.c
>>
>> Could you mail /etc/fstab, or put it on the CLFS list?
>> Also, are there any relevant kernel messages before the JFS Failure
>> message?
>>
>> bjd
>>
>>     
> Hi Bauke,
>     I just found out something interesting. When a system is up and
> running and you put a new file system on a partition and the wrong file
> system type is in the fstab, when you mount it and do a mount command to
> see it is mounted it shows the file system type that was in the fstab
> not the type that the file system actually is. Correcting the fstab
> after the file system is mounted does not change the output. You need to
> unmount the file system then re-mount it with the correct information in
> the fstab. Then when you do the mount to see it mounted it reports the
> correct file system type. I am wondering if it is just a reporting
> problem or if when mounted with the wrong information in fstab it really
> acts like the wrong file system. What I did was blow away my ext2 file
> system and used mkfs.ext3 to create a new one. So was it actually
> creating a journal while mount was reporting that it was an ext2 type? I
> was also surprised to find out that dumpe2fs does not report if the file
> system is ext2 or ext3. Now to see if it helped. I need to try to boot
> it. ;-) I'll let you know. OK, I just did the dumpe2fs on the ext3
> partition and under the options section it says "has_journal" where it
> didn't when it was ext2.
>
> Arnie
>
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>   
OK, I just tried to boot the CLFS after changing the root filesystem to
ext3. I wrote down what was left on the screen that looked relevant to
the problem. A lot scrolled by so there may have been something that I
didn't see. I have a question of all you gurus out there about the last
line and what it is talking about. Here are the last three lines on the
screen:

Mount JFS Failure: -22
No filesystem could mount root, tried: reiserfs ext3 ext4dev ext2 msdos
vfat iso9669 jfs
kernel panic - not syncing: VFS: unable to mount root fs on
unknown-block(8,49)

What does it mean by "unknown-block(8,49)"? The message seems to be
saying the kernel is trying to mount the filesystem "ON" this "block".
Is there somewhere I can go to get information about exactly what is
happening during the boot process? The messages that are still on the
screen before the the JFS Mount Failure don't seem relevant to me.
Another question I have is why is it even trying a JFS mount? Is there a
defined list of filesystems it tries without looking at the filesystem
first? Does anyone have any ideas what else I can try? I have one more
week of vacation to burn before the end of the year and I'd like to burn
it by building the applications I need from BLFS instead of beating my
head against this wall. :-) Thanks in advance for any help you can give me.

Arnie