Re: Linux-2.4.10 + ext3

[Andreas Dilger <adilger@turbolabs.com>]

On Sep 24, 2001  20:49 +0100, Jamie Lokier wrote:
> Andrew Morton wrote:
> > And the main reason for having the same on-disk format is not, IMO, to
> > ease migration between the two filesystems.  That's just a once-off
> > activity.
> 
> I disagree that it's a once-off activity.  I've been known to switch
> between ext2 and ext3 and ext2 and ext3...  just so I can boot old
> kernels such as rescue disks.  It's nice to be able to do this.

Well, you don't need to remove the journal just to boot off of a rescue
disk.  The only requirement is that you have a clean unmount of the ext3
filesystem (although if you DO have a booting problem that can also be a
bit of a challenge).

> Also I don't think resize2fs resizes the journal (but I may be wrong),
> so I've converted ext3 to ext2 to resize a filesystem, then converted
> back.

I think you're wrong on this one.  As long as you unmount the filesystem,
resize2fs should be able to handle it (as will ext2resize).

> I did have a big disaster once when I compiled ext3 into a kernel and
> not ext2 (which I left as a module).  You can guess, it couldn't mount
> the root filesystem.

Yes, this is one reason why removing the journal all the time is a bad
idea.  This won't be a problem at some point in the future when it is
possible for the ext3 code to mount an unjournaled filesystem (ala ext2),
but that still needs a bit of work that isn't very high priority.

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