From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34190) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ur9aH-0001X6-52 for qemu-devel@nongnu.org; Mon, 24 Jun 2013 12:25:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ur9aE-0000LL-CJ for qemu-devel@nongnu.org; Mon, 24 Jun 2013 12:25:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40617) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ur9aE-0000L8-1g for qemu-devel@nongnu.org; Mon, 24 Jun 2013 12:25:38 -0400 Message-ID: <51C872FA.9060404@redhat.com> Date: Mon, 24 Jun 2013 18:25:30 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1371934712-11714-1-git-send-email-pl@kamp.de> <1371934712-11714-7-git-send-email-pl@kamp.de> <51C858B3.7010200@redhat.com> <51C87120.9010105@kamp.de> In-Reply-To: <51C87120.9010105@kamp.de> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 6/8] qemu-img: use bdrv_write_zeroes to write zeroes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: Kevin Wolf , ronniesahlberg@gmail.com, qemu-devel@nongnu.org, Stefan Hajnoczi Il 24/06/2013 18:17, Peter Lieven ha scritto: > Am 24.06.2013 16:33, schrieb Paolo Bonzini: >> Il 22/06/2013 22:58, Peter Lieven ha scritto: >>> Signed-off-by: Peter Lieven >>> --- >>> qemu-img.c | 10 +++++++--- >>> 1 file changed, 7 insertions(+), 3 deletions(-) >>> >>> diff --git a/qemu-img.c b/qemu-img.c >>> index 809b4f1..5aa53ab 100644 >>> --- a/qemu-img.c >>> +++ b/qemu-img.c >>> @@ -1513,9 +1513,13 @@ static int img_convert(int argc, char **argv) >>> If the output is to a host device, we also write out >>> sectors that are entirely 0, since whatever data was >>> already there is garbage, not 0s. */ >>> - if (!has_zero_init || out_baseimg || >>> - is_allocated_sectors_min(buf1, n, &n1, min_sparse)) { >>> - ret = bdrv_write(out_bs, sector_num, buf1, n1); >>> + int allocated = is_allocated_sectors_min(buf1, n, &n1, min_sparse); >>> + if (!has_zero_init || out_baseimg || allocated) { >>> + if (allocated || out_baseimg) { >>> + ret = bdrv_write(out_bs, sector_num, buf1, n1); >>> + } else { >>> + ret = bdrv_write_zeroes(out_bs, sector_num, n1); >> I think it should still do the write only if !has_zero_init. > With this I am still in trouble with iSCSI, but Kevin pointed out another > possible solution for the allocating everything problem. > > a) let iscsi_create discard the whole device if lbpz && lbprz > b) return 1 for has_zero_init if lbprz. > > What do you think? Fine by me (but the discard may take a looong time! :)). Paolo