Ext3 users - Sep 2001 - Changing root journal data mode

Hi,

I'm running 2.4.9-ac7 with ext3 compiled in, and I ran across this problem.
Now that I look back, it makes sence, but it wasn't obvious at first...

I wanted to change the journal mode on my / partition, so I changed my fstab
to:

/dev/hda1 / ext3 defaults,errors=remount-ro,data=journal 0 1

as well as several other partitions, and rebooted.

After rebooting I had a read only / that I couldn't remount rw, and
couldn't
edit /etc/fstab without a boot disk.

After scrolling up, I found output from mount saying to the affect
"Can't
change journal mode while mounted".

I can try to reproduce the error if you need the exact error message.  While
I understand why this is happening, it wasn't very easy to recover, and I
didn't have any idea it would error out like that.

I guess there would be a kernel boot option to change the journal mode for
/, but I haven't taken the time to look yet...

Does it look like this will change, or are things staying like this?

Mike

On Sep 05, 2001  17:47 -0700, Mike Fedyk wrote:
> I'm running 2.4.9-ac7 with ext3 compiled in, and I ran across this
problem.
> Now that I look back, it makes sence, but it wasn't obvious at first...
> 
> I wanted to change the journal mode on my / partition, so I changed my
fstab
> to:
> 
> /dev/hda1 / ext3 defaults,errors=remount-ro,data=journal 0 1
> 
> as well as several other partitions, and rebooted.
> 
> After rebooting I had a read only / that I couldn't remount rw, and
couldn't
> edit /etc/fstab without a boot disk.
> 
> After scrolling up, I found output from mount saying to the affect
"Can't
> change journal mode while mounted".
You need to specify on the kernel command-line
"rootflags=data=journal".
For lilo and syslinux, this is done with
append="rootflags=data=journal".
> I guess there would be a kernel boot option to change the journal mode for
> /, but I haven't taken the time to look yet...
> 
> Does it look like this will change, or are things staying like this?
It may make sense to allow specifying the default data-journaling type
in the journal superblock.  I suppose it depends also on whether shared
journals (not implemented yet) will allow mixed-mode journaling, or if
they will require the same journaling mode for all clients.  Andrew, Stephen?

Cheers, Andreas
-- 
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert