From nobody Mon Feb 9 16:51:21 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1507780374842444.53903416301307; Wed, 11 Oct 2017 20:52:54 -0700 (PDT) Received: from localhost ([::1]:43544 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e2UYI-0006N1-37 for importer@patchew.org; Wed, 11 Oct 2017 23:52:54 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58139) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e2UTH-0002Wl-J3 for qemu-devel@nongnu.org; Wed, 11 Oct 2017 23:47:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e2UTG-0007Ha-MT for qemu-devel@nongnu.org; Wed, 11 Oct 2017 23:47:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48680) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e2UTC-0007D1-Un; Wed, 11 Oct 2017 23:47:39 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id F02D325774; Thu, 12 Oct 2017 03:47:37 +0000 (UTC) Received: from red.redhat.com (ovpn-122-223.rdu2.redhat.com [10.10.122.223]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4C04A6954A; Thu, 12 Oct 2017 03:47:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com F02D325774 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=eblake@redhat.com From: Eric Blake To: qemu-devel@nongnu.org Date: Wed, 11 Oct 2017 22:47:00 -0500 Message-Id: <20171012034720.11947-5-eblake@redhat.com> In-Reply-To: <20171012034720.11947-1-eblake@redhat.com> References: <20171012034720.11947-1-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 12 Oct 2017 03:47:38 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v6 04/24] qcow2: Switch is_zero_sectors() to byte-based X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, jsnow@redhat.com, famz@redhat.com, qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Convert another internal function (no semantic change), and rename it to is_zero() in the process. Signed-off-by: Eric Blake Reviewed-by: Fam Zheng Reviewed-by: John Snow --- v6: tweak comments to add TODO for later in series [Kevin], minor enough to keep R-b v3-v5: no change v2: rename function, rebase to upstream changes --- block/qcow2.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 990917096f..df53535455 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2999,21 +2999,29 @@ finish: } -static bool is_zero_sectors(BlockDriverState *bs, int64_t start, - uint32_t count) +static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes) { int nr; int64_t res; + int64_t start; - if (start + count > bs->total_sectors) { - count =3D bs->total_sectors - start; + /* TODO: Widening to sector boundaries should only be needed as + * long as we can't query finer granularity. */ + start =3D QEMU_ALIGN_DOWN(offset, BDRV_SECTOR_SIZE); + bytes =3D QEMU_ALIGN_UP(offset + bytes, BDRV_SECTOR_SIZE) - start; + + /* Clamp to image length, before checking status of underlying sectors= */ + if (start + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) { + bytes =3D bs->total_sectors * BDRV_SECTOR_SIZE - start; } - if (!count) { + if (!bytes) { return true; } - res =3D bdrv_get_block_status_above(bs, NULL, start, count, &nr, NULL); - return res >=3D 0 && (res & BDRV_BLOCK_ZERO) && nr =3D=3D count; + res =3D bdrv_get_block_status_above(bs, NULL, start >> BDRV_SECTOR_BIT= S, + bytes >> BDRV_SECTOR_BITS, &nr, NULL= ); + return res >=3D 0 && (res & BDRV_BLOCK_ZERO) && + nr * BDRV_SECTOR_SIZE =3D=3D bytes; } static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, @@ -3031,24 +3039,21 @@ static coroutine_fn int qcow2_co_pwrite_zeroes(Bloc= kDriverState *bs, } if (head || tail) { - int64_t cl_start =3D (offset - head) >> BDRV_SECTOR_BITS; uint64_t off; unsigned int nr; assert(head + bytes <=3D s->cluster_size); /* check whether remainder of cluster already reads as zero */ - if (!(is_zero_sectors(bs, cl_start, - DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) && - is_zero_sectors(bs, (offset + bytes) >> BDRV_SECTOR_BITS, - DIV_ROUND_UP(-tail & (s->cluster_size - 1), - BDRV_SECTOR_SIZE)))) { + if (!(is_zero(bs, offset - head, head) && + is_zero(bs, offset + bytes, + tail ? s->cluster_size - tail : 0))) { return -ENOTSUP; } qemu_co_mutex_lock(&s->lock); /* We can have new write after previous check */ - offset =3D cl_start << BDRV_SECTOR_BITS; + offset =3D QEMU_ALIGN_DOWN(offset, s->cluster_size); bytes =3D s->cluster_size; nr =3D s->cluster_size; ret =3D qcow2_get_cluster_offset(bs, offset, &nr, &off); --=20 2.13.6