From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39811) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VKVAu-0001MY-8G for qemu-devel@nongnu.org; Fri, 13 Sep 2013 11:20:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VKVAo-0008Nh-8T for qemu-devel@nongnu.org; Fri, 13 Sep 2013 11:20:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45962) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VKVAn-0008Na-Iv for qemu-devel@nongnu.org; Fri, 13 Sep 2013 11:20:41 -0400 Date: Fri, 13 Sep 2013 17:20:30 +0200 From: Kevin Wolf Message-ID: <20130913152030.GE2804@dhcp-200-207.str.redhat.com> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5232CBE3.3050503@redhat.com> 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: Paolo Bonzini Cc: Peter Lieven , Stefan Hajnoczi , qemu-devel@nongnu.org, Anthony Liguori 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. Kevin