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

Michael Poole
2006-06-09T18:17:57Z

Matthew Wilcox writes:

> On Fri, Jun 09, 2006 at 10:30:06AM -0700, Linus Torvalds wrote:
> > And I'm not saying that just because it's a filesystem, and people get
> > upset if they lose data. No, I'm saying it because from a maintenance
> > standpoint, such a filesystem has almost zero cost.
>
> One of the costs (and I'm not disagreeing with your main point;
> I think forking ext3 to ext4 at this point is reasonable), is that
> bugfixes applied to one don't necessarily get applied to the other.
> I found some recently between ext2 and ext3, and submitted those, but I
> only audited one file. There's lots more to look at and I just haven't
> found the time recently. Going to three variations is a lot more work
> for auditing, and it might be worth splitting some bits which genuinely
> are the same into common code.

If you want more details on this kind of issue, look at CP-Miner. A
paper published earlier this year in IEEE TSE[1] reports that that
tool found 421 cut-and-paste-related possible bugs in Linux, of which
49 were real bugs, 249 were false positives, and 123 could not be
proven either true or false positives.

[1]- http://doi.ieeecomputersociety.org/10.1109/TSE.2006.28

Michael Poole