Re: [PATCH][CFT] (updated) ext2 directories in pagecache

Andreas Dilger
2001-05-11T16:35:59Z

Al writes:
> On Fri, 11 May 2001, Andreas Dilger wrote:
> > I've tested again, now with kdb, and the system loops in ext2_find_entry()
> > or ext2_add_link(), because there is a directory with a zero rec_len.
> > While the actual cause of this problem is elsewhere, the fact that
> > ext2_next_entry() will loop forever with a bad rec_len is a bug not in
> > the old ext2 code.
>
> No. Bug is that data ends up in pages without being validated. That's
> the real thing to watch for - if ext2_get_page() is the only way to
> get pages in cache you get all checks in one place and done once.

OK, I don't think that Daniel is aware of this, I wasn't either. He
is using ext2_bread() modified to access the page cache instead of the
buffer cache.

It turns out that in adding the checks for rec_len, I fixed my original
bug, but added another... Please disregard my previous patch.

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