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

[Andrew Morton <akpm@osdl.org>]

On Sat, 3 Feb 2007 02:33:16 +0100
Nick Piggin <npiggin@suse.de> wrote:

> > > ===================================================================
> > > --- linux-2.6.orig/fs/buffer.c
> > > +++ linux-2.6/fs/buffer.c
> > > @@ -2344,6 +2344,8 @@ int nobh_prepare_write(struct page *page
> > >  
> > >  	if (is_mapped_to_disk)
> > >  		SetPageMappedToDisk(page);
> > > +
> > > +	/* XXX: information leak vs read(2) */
> > >  	SetPageUptodate(page);
> > >  
> > >  	/*
> > 
> > That comment is too terse to be useful.
> 
> OK, similar problem here - we have brought all the buffers uptodate
> that we are *not* going to write over, or partially write over, but
> we can have an uninitialised hole over the region we want to write.
> 
> I think just setting page uptodate in commit_write might do the
> trick? (and getting rid of the set_page_dirty there).

Yes, the page just isn't uptodate yet in prepare_write() - moving things
to commti_write() sounds sane.

But please, can we have sufficient changelogs and comments in the next version?