From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44798) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VLRcq-00083J-Ko for qemu-devel@nongnu.org; Mon, 16 Sep 2013 01:45:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VLRcj-0000Ue-AK for qemu-devel@nongnu.org; Mon, 16 Sep 2013 01:45:32 -0400 Received: from ssl.dlhnet.de ([91.198.192.8]:60382 helo=ssl.dlh.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VLRcj-0000UW-3R for qemu-devel@nongnu.org; Mon, 16 Sep 2013 01:45:25 -0400 Message-ID: <52369AF2.6050505@dlhnet.de> Date: Mon, 16 Sep 2013 07:45:22 +0200 From: Peter Lieven MIME-Version: 1.0 References: <1378481953-23099-1-git-send-email-stefanha@redhat.com> <1378481953-23099-34-git-send-email-stefanha@redhat.com> <5232BFDF.6000402@dlhnet.de> <5232CBE3.3050503@redhat.com> <20130913152030.GE2804@dhcp-200-207.str.redhat.com> In-Reply-To: <20130913152030.GE2804@dhcp-200-207.str.redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PULL 33/42] block: return BDRV_BLOCK_ZERO past end of backing file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Paolo Bonzini , Stefan Hajnoczi , qemu-devel@nongnu.org, Anthony Liguori On 13.09.2013 17:20, Kevin Wolf wrote: > Am 13.09.2013 um 10:25 hat Paolo Bonzini geschrieben: >> Il 13/09/2013 09:33, Peter Lieven ha scritto: >>> On 06.09.2013 17:39, Stefan Hajnoczi wrote: >>>> From: Paolo Bonzini >>>> >>>> If the sectors are unallocated and we are past the end of the >>>> backing file, they will read as zero. >>>> >>>> Signed-off-by: Paolo Bonzini >>>> Signed-off-by: Stefan Hajnoczi >>>> --- >>>> block.c | 12 ++++++++++-- >>>> 1 file changed, 10 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/block.c b/block.c >>>> index aa9ec83..82bbd6c 100644 >>>> --- a/block.c >>>> +++ b/block.c >>>> @@ -3102,8 +3102,16 @@ static int64_t coroutine_fn >>>> bdrv_co_get_block_status(BlockDriverState *bs, >>>> return ret; >>>> } >>>> - if (!(ret & BDRV_BLOCK_DATA) && bdrv_has_zero_init(bs)) { >>>> - ret |= BDRV_BLOCK_ZERO; >>>> + if (!(ret & BDRV_BLOCK_DATA)) { >>>> + if (bdrv_has_zero_init(bs)) { >>> this should be bdi->discard_zeroes. bdrv_has_zero_init() does only give >>> a valid result >>> right after bdrv_create(). i currently working on extending bdi. I can >>> send a patch for this >>> if you agree. >> Yes, please. Right now there is no bdi->discard_zeroes. > If we do this, it needs some function that behaves similar to > bdrv_has_zero_init(); in particular that it returns 0 if there is a > backing file. I will add bdrv_has_discard_zeroes. Would it be ok if it calls out to bdrv_get_info to get the discard_zeroes information? Peter