From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:53183)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <benoit.canet@irqsave.net>) id 1WLEQG-0008S1-MD
	for qemu-devel@nongnu.org; Wed, 05 Mar 2014 11:12:02 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <benoit.canet@irqsave.net>) id 1WLEQA-0001Y6-MH
	for qemu-devel@nongnu.org; Wed, 05 Mar 2014 11:11:56 -0500
Received: from lnantes-156-75-100-125.w80-12.abo.wanadoo.fr
	([80.12.84.125]:55735 helo=paradis.irqsave.net)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <benoit.canet@irqsave.net>) id 1WLEQA-0001Y0-GM
	for qemu-devel@nongnu.org; Wed, 05 Mar 2014 11:11:50 -0500
Date: Wed, 5 Mar 2014 17:11:50 +0100
From: =?iso-8859-1?Q?Beno=EEt?= Canet <benoit.canet@irqsave.net>
Message-ID: <20140305161150.GG1709@irqsave.net>
References: <1393860533-2063-1-git-send-email-mreitz@redhat.com>
	<1393860533-2063-6-git-send-email-mreitz@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
In-Reply-To: <1393860533-2063-6-git-send-email-mreitz@redhat.com>
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [PATCH 05/10] block/json: Add
 bdrv_co_get_block_status()
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Max Reitz <mreitz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>

The Monday 03 Mar 2014 =E0 16:28:48 (+0100), Max Reitz wrote :
> Implement this function in the same way as raw_bsd does: Acknowledge
> that this is a passthrough driver (always return BDRV_BLOCK_OFFSET_VALI=
D
> and BDRV_BLOCK_DATA and derive the offset directly from the sector
> index) and add BDRV_BLOCK_RAW to the returned value.
>=20
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/json.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>=20
> diff --git a/block/json.c b/block/json.c
> index a2f4691..7392802 100644
> --- a/block/json.c
> +++ b/block/json.c
> @@ -113,6 +113,14 @@ static coroutine_fn int json_co_write_zeroes(Block=
DriverState *bs,
>      return bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags);
>  }
> =20
> +static coroutine_fn int64_t json_co_get_block_status(BlockDriverState =
*bs,
> +                                                     int64_t sector_nu=
m,
> +                                                     int nb_sectors, i=
nt *pnum)
> +{
> +    return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA =
|
> +           (sector_num << BDRV_SECTOR_BITS);
> +}

I don't understand what is the selling point of this method instead of ca=
lling
bdrv_co_get_block_status on bs->file.
Some information risk to be lost and it does look like magic.

Best regards

Beno=EEt

> +
>  static void json_invalidate_cache(BlockDriverState *bs)
>  {
>      return bdrv_invalidate_cache(bs->file);
> @@ -159,6 +167,7 @@ static BlockDriver bdrv_json =3D {
>      .bdrv_aio_discard           =3D json_aio_discard,
> =20
>      .bdrv_co_write_zeroes       =3D json_co_write_zeroes,
> +    .bdrv_co_get_block_status   =3D json_co_get_block_status,
> =20
>      .bdrv_invalidate_cache      =3D json_invalidate_cache,
> =20
> --=20
> 1.9.0
>=20
>=20