Re: [patch 1/9] fs: libfs buffered write leak fix

[Jörn Engel <joern@lazybastard.org>]

On Sat, 3 February 2007 02:33:16 +0100, Nick Piggin wrote:
> 
> If doing a partial-write, simply clear the whole page and set it uptodate
> (don't need to get too tricky).

That sounds just like a bug I recently fixed in logfs.  prepare_write()
would clear the page, commit_write() would write the whole page.  Bug
can be reproduced with a simple testcate:

echo -n foo > foo
echo -n bar >> foo
cat foo

With the bug, the second write will replace "foo" with "\0\0\0" and
cat will return "bar".  Doing a read instead of clearing the page will
return "foobar", as would be expected.

Can you hit the same bug with your patch or did I miss something?

Jörn

-- 
When people work hard for you for a pat on the back, you've got
to give them that pat.
-- Robert Heinlein
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