Re: Snapshot target and DAX-capable devices

Jeff Moyer
2018-08-30T19:53:36Z

Mikulas Patocka <mpatocka@redhat.com> writes:

> On Thu, 30 Aug 2018, Jeff Moyer wrote:
>
>> Mike Snitzer <snitzer@redhat.com> writes:
>>
>> > Until we properly add DAX support to dm-snapshot I'm afraid we really do
>> > need to tolerate this "regression". Since reality is the original
>> > support for snapshot of a DAX DM device never worked in a robust way.
>>
>> Agreed.
>>
>> -Jeff
>
> You can't support dax on snapshot - if someone maps a block and the block
> needs to be moved, then what?

That's exactly the point I brought up in my reply to Jan. You'd have to
unmap all mappings of the page/block.

-Jeff