Re: [PATCH v2 3/3] DAX: mmap write readonly file

Jeff Moyer
2017-04-11T13:56:16Z

Eryu Guan <eguan@redhat.com> writes:

> On Mon, Apr 10, 2017 at 02:05:53PM +0800, Xiong Zhou wrote:
>> Regression case that one can write to read-only
>> file in a DAX mountpoint.
>>
>> Signed-off-by: Xiong Zhou <xzhou@redhat.com>
>> ---
>>
>> v2:
>> compile test programme manually in this test because default
>> cc option -O2 prevents this issue reproduction;
>
> Hmm, this looks.. ugly to me :) Better to find out the exact reason that
> prevents the bug from reproducing and update the c program accordingly.

The compiler probably optimizes this bit out:

+ /* fault in the page */
+ foo = *buf;

Cheers,
Jeff