[dm-devel] Snapshot target and DAX-capable devices

Jeff Moyer jmoyer at redhat.com
Thu Aug 30 19:53:31 UTC 2018

Mikulas Patocka <mpatocka at redhat.com> writes:

> On Thu, 30 Aug 2018, Jeff Moyer wrote:
>> Mike Snitzer <snitzer at 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.


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