From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:37151)
	by lists.gnu.org with esmtp (Exim 4.71) (envelope-from <pl@kamp.de>)
	id 1YJhqF-0000AT-G7
	for qemu-devel@nongnu.org; Fri, 06 Feb 2015 07:17:00 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pl@kamp.de>) id 1YJhqC-0007Q6-5u
	for qemu-devel@nongnu.org; Fri, 06 Feb 2015 07:16:59 -0500
Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:35033 helo=mx01.kamp.de)
	by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from <pl@kamp.de>)
	id 1YJhqB-0007Pf-Sd
	for qemu-devel@nongnu.org; Fri, 06 Feb 2015 07:16:56 -0500
Message-ID: <54D4B0B3.10107@kamp.de>
Date: Fri, 06 Feb 2015 13:16:51 +0100
From: Peter Lieven <pl@kamp.de>
MIME-Version: 1.0
References: <1423220051-16058-1-git-send-email-pl@kamp.de>
	<1423221883-16804-1-git-send-email-den@openvz.org>
	<20150206115347.GB13081@noname.redhat.com>
In-Reply-To: <20150206115347.GB13081@noname.redhat.com>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH 1/1] nbd: fix
	max_discard/max_transfer_length
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: Kevin Wolf <kwolf@redhat.com>, "Denis V. Lunev" <den@openvz.org>
Cc: qemu-devel@nongnu.org

Am 06.02.2015 um 12:53 schrieb Kevin Wolf:
> Am 06.02.2015 um 12:24 hat Denis V. Lunev geschrieben:
>> nbd_co_discard calls nbd_client_session_co_discard which uses uint32_t
>> as the length in bytes of the data to discard due to the following
>> definition:
>>
>> struct nbd_request {
>>     uint32_t magic;
>>     uint32_t type;
>>     uint64_t handle;
>>     uint64_t from;
>>     uint32_t len; <-- the length of data to be discarded, in bytes
>> } QEMU_PACKED;
>>
>> Thus we should limit bl_max_discard to UINT32_MAX >> BDRV_SECTOR_BITS to
>> avoid overflow.
>>
>> NBD read/write code uses the same structure for transfers. Fix
>> max_transfer_length accordingly.
>>
>> Signed-off-by: Denis V. Lunev <den@openvz.org>
>> CC: Peter Lieven <pl@kamp.de>
>> CC: Kevin Wolf <kwolf@redhat.com>
> Thanks, I have applied both Peter's and your patch. Can you guys please
> check whether the current state of my block branch is correct or whether
> I forgot to include or remove some patch?

Looks good from my point of view.

Just to be sure has it to be

if (size > BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)

or

if (size > (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS))

?

If the latter is right, can you please fix that line in my patch. I am afk now.

Thanks,
Peter