From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45003) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VLRf2-0000T0-Ho for qemu-devel@nongnu.org; Mon, 16 Sep 2013 01:47:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VLRex-00012s-0F for qemu-devel@nongnu.org; Mon, 16 Sep 2013 01:47:48 -0400 Received: from mx.ipv6.kamp.de ([2a02:248:0:51::16]:59869 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VLRew-00012d-LK for qemu-devel@nongnu.org; Mon, 16 Sep 2013 01:47:42 -0400 Message-ID: <52369B70.2030504@kamp.de> Date: Mon, 16 Sep 2013 07:47:28 +0200 From: Peter Lieven MIME-Version: 1.0 References: <1379067909-22984-1-git-send-email-pl@kamp.de> <1379067909-22984-13-git-send-email-pl@kamp.de> In-Reply-To: <1379067909-22984-13-git-send-email-pl@kamp.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 12/12] block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org, ronniesahlberg@gmail.com, anthony@codemonkey.ws, pbonzini@redhat.com On 13.09.2013 12:25, Peter Lieven wrote: > this patch does 2 things: > a) only do additional call outs if BDRV_BLOCK_ZERO is not already set. > b) use bdi.discard_zeroes to return the zero state of an unallocated block. > the callout to bdrv_has_zero_init() is only valid right after bdrv_create. > > Signed-off-by: Peter Lieven > --- > block.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/block.c b/block.c > index 282943b..6698c10 100644 > --- a/block.c > +++ b/block.c > @@ -3153,8 +3153,10 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, > return ret; > } > > - if (!(ret & BDRV_BLOCK_DATA)) { > - if (bdrv_has_zero_init(bs)) { > + if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) { > + BlockDriverInfo bdi; > + if (bdrv_get_info(bs, &bdi) == 0 && > + bdi.discard_zeroes) { > ret |= BDRV_BLOCK_ZERO; > } else if (bs->backing_hd) { > BlockDriverState *bs2 = bs->backing_hd; Kevin, according to your comment that we need a separate function like bdrv_has_discard_zeroes. It should also be ok to change the order and first check for bs->backing_hd here or not? Peter