Partitions and end-to-end protection

[Dan Williams]

On Tue, Jul 14, 2015 at 11:06 AM, Christoph Hellwig <hch at infradead.org> wrote:
> On Mon, Jul 13, 2015 at 07:16:25PM +0000, Keith Busch wrote:
>> On Mon, 13 Jul 2015, Paul Grabinar wrote:
>> >What seems to be happening is that the driver starts off by setting the
>> >capacity to zero whilst it validates the meta-data configuration and
>> >then sets the real size after this validation. However, setting the
>> >capacity does not seem to be enough to tell the kernel to re-read the
>> >partition table.
>>
>> The driver did it this way because we need a disk allocated before we can
>> subscribe to block integrity extensions. I think we can fix the partition
>> issue by making a call to blkdev_reread_part() right after the second
>> revalidate_disk if the namespace is a meta-data formatted. I'll test it
>> out and post a patch if it works out.
>
> I dont think requiring this crazy scheme is something that should spread
> in drivers.  I'd suggest you work with Martin (on Cc) so that we can
> set up the integrity profile at the right time.
>

We got bit by this in the nvdimm enabling as well, it is mostly hidden
by the fact that sd triggers revalidate_disk() by default.