Re: [Ext2-devel] [RFC 0/13] extents and 48bit ext3

Kyle Moffett
2006-06-10T19:27:36Z

On Jun 9, 2006, at 15:01:20, Jeff Garzik wrote:
> Chase Venters wrote:
>> Now, granted, I really do agree with you about the whole code
>> sharing thing. A fresh start is often just what you need. I'm just
>> questioning if it wouldn't be better to do this fresh start
>> immediately after going 48-bit, rather than before. That way,
>> existing users that want that extra umph can have it today.
>
> Then you continue to crap up the code with
>
> if (48bit)
> ...
> else
> ...
>
> etc.
>
> The proper way to do this is "cp -a ext3 ext4" (excluding JBD as
> Andrew mentioned), and then let evolution take its course.

Why not: "extX_ops.do_something_useful();", then have fs/ext/ext
{2,3,4}_ops.c which implement those various operations just like we
do for the Virtual Filesystem Switch? Much as there are
commonalities between all filesystems that get moved into the VFS;
perhaps we should have a Virtual Ext Filesystem Switch (VEFS?
VextFS?) which abstracts out the commonalities between the evolving
ext{2,3} code and data format? Such code would also provide a
library of common routines which could be used to implement other
specialized filesystems in the future. Imagine a cluster-extfs which
reuses some of the core extXfs code despite changing the on-disk
format considerably!

Cheers,
Kyle Moffett