Re: [PATCH v3 1/1] vfs: iversion truncate bug fix

From: Greg KH
Date: Thu Jan 05 2012 - 11:54:39 EST


On Wed, Jan 04, 2012 at 11:17:12PM -0500, Mimi Zohar wrote:
> On Wed, 2012-01-04 at 18:06 -0800, Greg KH wrote:
> > On Wed, Jan 04, 2012 at 04:46:38PM -0800, Andrew Morton wrote:
> > > On Wed, 04 Jan 2012 19:33:49 -0500
> > > Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > > On Wed, 2012-01-04 at 15:28 -0800, Andrew Morton wrote:
> > > > > On Thu, 22 Dec 2011 08:26:30 -0500
> > > > > Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> wrote:
> > > > >
> > > > > > On Thu, 2011-12-22 at 12:54 +0200, Dmitry Kasatkin wrote:
> > > > > > > When a file is truncated with truncate()/ftruncate() and then closed,
> > > > > > > iversion is not updated. This patch uses ATTR_SIZE flag as an indication
> > > > > > > to increment iversion.
> > > > > > >
> > > > > > > Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx>
> > > > > >
> > > > > > Acked-by: Mimi Zohar <zohar@xxxxxxxxxx>
> > > > > > (Stable should be cc'ed on this patch.)
> > > > >
> > > > > why?
> > > >
> > > > Why backported?
> > >
> > > Yes. If you want to submit the patch to the -stable maintainer then
> > > you should explain to him why the fix is important enough to warrant
> > > doing that. That involves explaining the user-visible effects of
> > > the bug.
> > >
> > > > The IMA measurement list could be incomplete.
> > >
> > > In more detail than this. Maybe he knows what the above sentence
> > > means, but I sure don't.
> >
> > Nope, I don't either :)
>
> On fput(), i_version is used to detect and flag files that have changed
> and need to be re-measured in the IMA measurement policy. When a file
> is truncated with truncate()/ftruncate() and then closed, i_version is
> not updated. As a result, although the file has changed, it will not be
> re-measured and added to the IMA measurement list on subsequent access.

And what am I supposed to do with this?

Please, go read Documentation/stable_kernel_rules.txt for how to
properly submit patches to the stable kernel tree. The information here
needs to be in the patch changelog itself, not in some random email
thread that will get lost instantly into my email-archive-from-hell
after I am done reading this.

greg k-h
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