[dm-devel] [PATCH] dm mpath: enable WRITE SAME support

[Bharata B Rao]

On Wed, May 1, 2013 at 6:59 PM, Mike Snitzer <snitzer at redhat.com> wrote:
>
> The multipath target did not opt-in to supporting WRITE SAME.  Please
> try this patch.
>
> From: Mike Snitzer <snitzer at redhat.com>
> Subject: [PATCH] dm mpath: enable WRITE SAME support
>
> There is no reason to disallow WRITE SAME support.  As far as multipath
> is concerned it is just another write request.
>
> Signed-off-by: Mike Snitzer <snitzer at redhat.com>
> ---
>  drivers/md/dm-mpath.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> index 51bb816..bdf26f5 100644
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -907,6 +907,7 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
>
>         ti->num_flush_bios = 1;
>         ti->num_discard_bios = 1;
> +       ti->num_write_same_bios = 1;

With this patch, I can see the LV that is on multipath device,
advertising the WRITE SAME support and I am able to successfully issue
BLKZEROOUT ioctl to that LV.

Regards,
Bharata.