Re: Ext2fs 2GB limit status?

[Ognyan Kulev]

Marco Gerards wrote:
> Ok. Perhaps it is interesting to discuss journaling.  AFAIK Linux has
> some journaling code shared by all filesystems.

It doesn't.  There is an "universal" JBD layer that is designed to be 
used by any filesystem, but currently only ext3 uses it.

> Perhaps it is useful to extend libdiskfs with such feature.

I'm still on the block layer, but changing libdiskfs to support 
journalling seems almost inevitable for ext3fs support at first glance.

> Perhaps you can share some
> code for removing the 2GB limit too?  I think it is a waste of time to
> fix the limit for every individual filesystem.

Actually, fixing the 2G limit was just a step towards ext3fs for me.  It 
helped me a lot to go deeper in ext2 and the Hurd.  In ext3fs, there 
will be much more changes in the block layer, which (if core developers 
like it) will be integrated in ext2fs.  I even think about integrating 
some kind of soft deps, like in BSDs.  But for now, it is much more 
important to have _some_ ext2fs without this stupid limit that makes 
others laugh at us.  Unfortunately, ext3fs must be finished ASAP for 
personal reasons.

> I'm even thinking about how easy it is, if this is really general, to
> add journaling and ordered writes to filesystems that don't even
> officially support this by just having a nice journaling
> layer. (This is just a random thought that is possibly quite useless).

That's the idea of JBD, but noone uses it in this way yet.  It's not an 
easy job to journal random filesystem with JBD, though.

Regards,
ogi