[dm-devel] [PATCH 0/6] Support DAX for device-mapper dm-linear devices

[Mike Snitzer]

On Mon, Jun 13 2016 at  6:21pm -0400,
Toshi Kani <toshi.kani at hpe.com> wrote:

> This patch-set adds DAX support to device-mapper dm-linear devices
> used by LVM.  It works with LVM commands as follows:
>  - Creation of a logical volume with all DAX capable devices (such
>    as pmem) sets the logical volume DAX capable as well.
>  - Once a logical volume is set to DAX capable, the volume may not
>    be extended with non-DAX capable devices.
> 
> The direct_access interface is added to dm and dm-linear to map
> a request to a target device.
> 
>  - Patch 1-2 introduce GENHD_FL_DAX flag to indicate DAX capability.
>  - Patch 3-4 add direct_access functions to dm and dm-linear.
>  - Patch 5-6 set GENHD_FL_DAX to dm when all targets are DAX capable.
> 
> ---
> Toshi Kani (6):
>  1/6 genhd: Add GENHD_FL_DAX to gendisk flags
>  2/6 block: Check GENHD_FL_DAX for DAX capability
>  3/6 dm: Add dm_blk_direct_access() for mapped device
>  4/6 dm-linear: Add linear_direct_access()
>  5/6 dm, dm-linear: Add dax_supported to dm_target
>  6/6 dm: Enable DAX support for mapper device

Thanks a lot for doing this.  I recently added it to my TODO so your
patches come at a great time.

I'll try to get to reviewing/testing your work by the end of this week.

Mike