From nobody Sat Nov 15 12:45:33 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1595339806; cv=none; d=zohomail.com; s=zohoarc; b=CBHphStIW3osop9BVB8rCfpZS+iydcjCLLc3KMIHsSINlxiyOHfm0t0D4piM8VG91LFof3/H0qai6nstgKqi5oNDJaZ+emj+TP50qAw64UA8WlJoM6IMGSKH7WoT2S0s4dCsPXaRwxd4z+izEExS2cViwCtW+30SnEDKvf62cA0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1595339806; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=pKcGHN9BiCQRQAAgwMmB3i4OhnaN31yh4S3mMqcJVPM=; b=I6cCtJoGNBLXt4pLncYoxU5Y2WRWMG2EFbeGNSyBx5UdKNqMIFXHQb4hRqujU4Ei+kX6zJd/hQJQDuncbwCsyH545ZaVQiE9bHkrSC6pY3QE7S/UeBiYCRV8hDFBxn+SxRMk4/6k+Lf9XbjNvJ5MnmrsYpsZcwEUA7R8DpwnBs8= ARC-Authentication-Results: i=1; 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Tue, 21 Jul 2020 09:55:31 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-340-b2QjUC6aMrKwAC7ojI3q1Q-1; Tue, 21 Jul 2020 09:55:28 -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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5B41F1083FA5; Tue, 21 Jul 2020 13:55:27 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-113-97.ams2.redhat.com [10.36.113.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 40E7E59; Tue, 21 Jul 2020 13:55:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595339729; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=pKcGHN9BiCQRQAAgwMmB3i4OhnaN31yh4S3mMqcJVPM=; b=XiYqy5VzhglXvBEiaHsB8yX0naNzfVTOFn4DKnOLLtoJSsIYMKANRr332WDBW8j7zA1wb9 k7HK8+HM43wKL4IkUs6KTov0nER+5vmBdcrUJO3QNfsTo+ChqrtrokMMKkOlzzEAqeFqGC aa+U4FIGj07UpDYp+0A4g6p9Ntblk2o= X-MC-Unique: b2QjUC6aMrKwAC7ojI3q1Q-1 From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH for-5.1 v2 1/2] qcow2: Implement v2 zero writes with discard if possible Date: Tue, 21 Jul 2020 15:55:19 +0200 Message-Id: <20200721135520.72355-2-kwolf@redhat.com> In-Reply-To: <20200721135520.72355-1-kwolf@redhat.com> References: <20200721135520.72355-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=205.139.110.120; envelope-from=kwolf@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/21 01:30:29 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, nsoffer@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" qcow2 version 2 images don't support the zero flag for clusters, so for write_zeroes requests, we return -ENOTSUP and get explicit zero buffer writes. If the image doesn't have a backing file, we can do better: Just discard the respective clusters. This is relevant for 'qemu-img convert -O qcow2 -n', where qemu-img has to assume that the existing target image may contain any data, so it has to write zeroes. Without this patch, this results in a fully allocated target image, even if the source image was empty. Reported-by: Nir Soffer Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- block/qcow2-cluster.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 4b5fc8c4a7..a677ba9f5c 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1797,8 +1797,15 @@ int qcow2_cluster_zeroize(BlockDriverState *bs, uint= 64_t offset, assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) || end_offset >=3D bs->total_sectors << BDRV_SECTOR_BITS); =20 - /* The zero flag is only supported by version 3 and newer */ + /* + * The zero flag is only supported by version 3 and newer. However, if= we + * have no backing file, we can resort to discard in version 2. + */ if (s->qcow_version < 3) { + if (!bs->backing) { + return qcow2_cluster_discard(bs, offset, bytes, + QCOW2_DISCARD_REQUEST, false); + } return -ENOTSUP; } =20 --=20 2.25.4 From nobody Sat Nov 15 12:45:33 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1595339808; cv=none; d=zohomail.com; s=zohoarc; b=Kq6Qb5dO3cGp8xB1OEO90NnseIOvUpPktUB/3acC+vYxyZ1xjdHNzGWsRxxlP/nGg+MG7TvfY68qA4nqB9piD2sfE0OVbQJfvFapOl+6g/OxaCcD8x3heij1CBljdbHqhFgtEND+VJR3UD9VdHjZtyePpsuhNdhn/y/WUyKlfX8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1595339808; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; 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c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595339731; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XiRcHwsEu67CK5FfrlnOPel9std7EgSdCj+MvoPyuhM=; b=TrfZwHmGf7vcOo5EnPXGx6jw8a1RXuNIczZNgkr3zSkV+kKlun38dVy9sVelm1nCYmwbOo ad4zzpNORJyi2xgXJN1Xr9bLyX2bwUQc114Fn/dQGXtCl6UStVhNhqNawquL9szxU1wMnX qgtsoJgddtBgHuTWx0JD8unng8fC5Zw= X-MC-Unique: llCgb1jxN_2y0iWKK8WU6g-1 From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH for-5.1 v2 2/2] iotests: Test sparseness for qemu-img convert -n Date: Tue, 21 Jul 2020 15:55:20 +0200 Message-Id: <20200721135520.72355-3-kwolf@redhat.com> In-Reply-To: <20200721135520.72355-1-kwolf@redhat.com> References: <20200721135520.72355-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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charset="utf-8" Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- tests/qemu-iotests/122 | 30 ++++++++++++++++++++++++++++++ tests/qemu-iotests/122.out | 17 +++++++++++++++++ 2 files changed, 47 insertions(+) diff --git a/tests/qemu-iotests/122 b/tests/qemu-iotests/122 index dfd1cd05d6..0f3d4ca851 100755 --- a/tests/qemu-iotests/122 +++ b/tests/qemu-iotests/122 @@ -281,6 +281,36 @@ $QEMU_IMG convert -O $IMGFMT -n "$TEST_IMG" "$TEST_IMG= ".orig =20 $QEMU_IMG compare "$TEST_IMG" "$TEST_IMG".orig =20 +echo +echo '=3D=3D=3D -n to an empty image =3D=3D=3D' +echo + +TEST_IMG=3D"$TEST_IMG".orig _make_test_img 64M + +# Convert with -n, which should not result in a fully allocated image, not= even +# with compat=3D0.10 (because the target doesn't have a backing file) +for compat in "1.1" "0.10"; do + IMGOPTS=3D"compat=3D$compat" _make_test_img 64M + $QEMU_IMG convert -O $IMGFMT -n "$TEST_IMG".orig "$TEST_IMG" + $QEMU_IMG map --output=3Djson "$TEST_IMG" +done + +echo +echo '=3D=3D=3D -n to an empty image with a backing file =3D=3D=3D' +echo + +TEST_IMG=3D"$TEST_IMG".orig _make_test_img 64M +TEST_IMG=3D"$TEST_IMG".base _make_test_img 64M + +# Convert with -n, which should still not result in a fully allocated imag= e for +# compat=3D1.1 (because it can use zero clusters), but it should be fully +# allocated with compat=3D0.10 +for compat in "1.1" "0.10"; do + IMGOPTS=3D"compat=3D$compat" _make_test_img -b "$TEST_IMG".base -F $IM= GFMT 64M + $QEMU_IMG convert -O $IMGFMT -n "$TEST_IMG".orig "$TEST_IMG" + $QEMU_IMG map --output=3Djson "$TEST_IMG" +done + echo echo '=3D=3D=3D -n -B to an image without a backing file =3D=3D=3D' echo diff --git a/tests/qemu-iotests/122.out b/tests/qemu-iotests/122.out index f1f195ed77..3a3e121d57 100644 --- a/tests/qemu-iotests/122.out +++ b/tests/qemu-iotests/122.out @@ -229,6 +229,23 @@ wrote 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) Images are identical. =20 +=3D=3D=3D -n to an empty image =3D=3D=3D + +Formatting 'TEST_DIR/t.IMGFMT.orig', fmt=3DIMGFMT size=3D67108864 +Formatting 'TEST_DIR/t.IMGFMT', fmt=3DIMGFMT size=3D67108864 +[{ "start": 0, "length": 67108864, "depth": 0, "zero": true, "data": false= }] +Formatting 'TEST_DIR/t.IMGFMT', fmt=3DIMGFMT size=3D67108864 +[{ "start": 0, "length": 67108864, "depth": 0, "zero": true, "data": false= }] + +=3D=3D=3D -n to an empty image with a backing file =3D=3D=3D + +Formatting 'TEST_DIR/t.IMGFMT.orig', fmt=3DIMGFMT size=3D67108864 +Formatting 'TEST_DIR/t.IMGFMT.base', fmt=3DIMGFMT size=3D67108864 +Formatting 'TEST_DIR/t.IMGFMT', fmt=3DIMGFMT size=3D67108864 backing_file= =3DTEST_DIR/t.IMGFMT.base backing_fmt=3DIMGFMT +[{ "start": 0, "length": 67108864, "depth": 0, "zero": true, "data": false= }] +Formatting 'TEST_DIR/t.IMGFMT', fmt=3DIMGFMT size=3D67108864 backing_file= =3DTEST_DIR/t.IMGFMT.base backing_fmt=3DIMGFMT +[{ "start": 0, "length": 67108864, "depth": 0, "zero": false, "data": true= , "offset": 327680}] + =3D=3D=3D -n -B to an image without a backing file =3D=3D=3D =20 Formatting 'TEST_DIR/t.IMGFMT.base', fmt=3DIMGFMT size=3D67108864 --=20 2.25.4