[dm-devel] Question about which types of dm need to support DAX

[Yang, Xiao/杨 晓]

Hi Jeff,

Thanks a lot for your reply.

On 2022/9/27 3:52, Jeff Moyer wrote:
> "Yang, Xiao/杨 晓" <yangx.jy at fujitsu.com> writes:
> 
>> Hi Ross, Toshi, Jeff and others
>>
>> After reading the kernel patches[1][2][3] about dm, I think only three
>> types(linear, stripe and log-writes) of dm can support DAX now, right?
> 
> Right.
> 
>> I wonder why only three types of dm need to support DAX? Is there any
>> reason/history and use case?
> 
> It was easy to add DAX support to those targets.  Note that if a target
> needs to intercept I/O, then it is fundamentally incompatible with DAX.

How can I know which target needs to intercept I/O? Could you tell me 
why it is fundamentally incompatible with DAX?

Best Regards,
Xiao Yang
> 
> Cheers,
> Jeff
>