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GET /api/patches/813522/?format=api
{ "id": 813522, "url": "http://patchwork.ozlabs.org/api/patches/813522/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170913160333.23622-5-eblake@redhat.com/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api", "name": "QEMU Development", "link_name": "qemu-devel", "list_id": "qemu-devel.nongnu.org", "list_email": "qemu-devel@nongnu.org", "web_url": "", "scm_url": "", "webscm_url": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20170913160333.23622-5-eblake@redhat.com>", "list_archive_url": null, "date": "2017-09-13T16:03:14", "name": "[v4,04/23] qcow2: Switch is_zero_sectors() to byte-based", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "260d733f8fdcb880a0f1f44b15981aff6a0a897c", "submitter": { "id": 6591, "url": "http://patchwork.ozlabs.org/api/people/6591/?format=api", "name": "Eric Blake", "email": "eblake@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170913160333.23622-5-eblake@redhat.com/mbox/", "series": [ { "id": 2944, "url": "http://patchwork.ozlabs.org/api/series/2944/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=2944", "date": "2017-09-13T16:03:10", "name": "make bdrv_get_block_status byte-based", "version": 4, "mbox": "http://patchwork.ozlabs.org/series/2944/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/813522/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/813522/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@bilbo.ozlabs.org", "Authentication-Results": [ "ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=208.118.235.17; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=<UNKNOWN>)", "ext-mx01.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com", "ext-mx01.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=eblake@redhat.com" ], "Received": [ "from lists.gnu.org (lists.gnu.org [208.118.235.17])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xsmzw2c5wz9s72\n\tfor <incoming@patchwork.ozlabs.org>;\n\tThu, 14 Sep 2017 02:18:20 +1000 (AEST)", "from localhost ([::1]:43426 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>)\n\tid 1dsAMk-0008Pz-C6\n\tfor incoming@patchwork.ozlabs.org; Wed, 13 Sep 2017 12:18:18 -0400", "from eggs.gnu.org ([2001:4830:134:3::10]:45616)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <eblake@redhat.com>) id 1dsA95-0001HR-W6\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 12:04:13 -0400", "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <eblake@redhat.com>) id 1dsA91-0005vj-Uo\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 12:04:11 -0400", "from mx1.redhat.com ([209.132.183.28]:33706)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <eblake@redhat.com>)\n\tid 1dsA8u-0005pf-QU; Wed, 13 Sep 2017 12:04:01 -0400", "from smtp.corp.redhat.com\n\t(int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id D78D481E13;\n\tWed, 13 Sep 2017 16:03:59 +0000 (UTC)", "from red.redhat.com (ovpn-120-201.rdu2.redhat.com [10.10.120.201])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id E00ED5C6D2;\n\tWed, 13 Sep 2017 16:03:51 +0000 (UTC)" ], "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com D78D481E13", "From": "Eric Blake <eblake@redhat.com>", "To": "qemu-devel@nongnu.org", "Date": "Wed, 13 Sep 2017 11:03:14 -0500", "Message-Id": "<20170913160333.23622-5-eblake@redhat.com>", "In-Reply-To": "<20170913160333.23622-1-eblake@redhat.com>", "References": "<20170913160333.23622-1-eblake@redhat.com>", "X-Scanned-By": "MIMEDefang 2.79 on 10.5.11.11", "X-Greylist": "Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.25]);\n\tWed, 13 Sep 2017 16:04:00 +0000 (UTC)", "X-detected-operating-system": "by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]", "X-Received-From": "209.132.183.28", "Subject": "[Qemu-devel] [PATCH v4 04/23] qcow2: Switch is_zero_sectors() to\n\tbyte-based", "X-BeenThere": "qemu-devel@nongnu.org", "X-Mailman-Version": "2.1.21", "Precedence": "list", "List-Id": "<qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<http://lists.nongnu.org/archive/html/qemu-devel/>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Cc": "kwolf@redhat.com, jsnow@redhat.com, famz@redhat.com,\n\tqemu-block@nongnu.org, Max Reitz <mreitz@redhat.com>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "\"Qemu-devel\"\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>" }, "content": "We are gradually converting to byte-based interfaces, as they are\neasier to reason about than sector-based. Convert another internal\nfunction (no semantic change), and rename it to is_zero() in the\nprocess.\n\nSigned-off-by: Eric Blake <eblake@redhat.com>\nReviewed-by: Fam Zheng <famz@redhat.com>\n---\nv3: no change\nv2: rename function, rebase to upstream changes\n---\n block/qcow2.c | 32 ++++++++++++++++++--------------\n 1 file changed, 18 insertions(+), 14 deletions(-)", "diff": "diff --git a/block/qcow2.c b/block/qcow2.c\nindex 9a7b5cd41f..eb498b56d4 100644\n--- a/block/qcow2.c\n+++ b/block/qcow2.c\n@@ -2971,21 +2971,28 @@ finish:\n }\n\n\n-static bool is_zero_sectors(BlockDriverState *bs, int64_t start,\n- uint32_t count)\n+static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)\n {\n int nr;\n int64_t res;\n+ int64_t start;\n\n- if (start + count > bs->total_sectors) {\n- count = bs->total_sectors - start;\n+ /* Widen to sector boundaries, then clamp to image length, before\n+ * checking status of underlying sectors */\n+ start = QEMU_ALIGN_DOWN(offset, BDRV_SECTOR_SIZE);\n+ bytes = QEMU_ALIGN_UP(offset + bytes, BDRV_SECTOR_SIZE) - start;\n+\n+ if (start + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) {\n+ bytes = bs->total_sectors * BDRV_SECTOR_SIZE - start;\n }\n\n- if (!count) {\n+ if (!bytes) {\n return true;\n }\n- res = bdrv_get_block_status_above(bs, NULL, start, count, &nr, NULL);\n- return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count;\n+ res = bdrv_get_block_status_above(bs, NULL, start >> BDRV_SECTOR_BITS,\n+ bytes >> BDRV_SECTOR_BITS, &nr, NULL);\n+ return res >= 0 && (res & BDRV_BLOCK_ZERO) &&\n+ nr * BDRV_SECTOR_SIZE == bytes;\n }\n\n static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,\n@@ -3003,24 +3010,21 @@ static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,\n }\n\n if (head || tail) {\n- int64_t cl_start = (offset - head) >> BDRV_SECTOR_BITS;\n uint64_t off;\n unsigned int nr;\n\n assert(head + bytes <= s->cluster_size);\n\n /* check whether remainder of cluster already reads as zero */\n- if (!(is_zero_sectors(bs, cl_start,\n- DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) &&\n- is_zero_sectors(bs, (offset + bytes) >> BDRV_SECTOR_BITS,\n- DIV_ROUND_UP(-tail & (s->cluster_size - 1),\n- BDRV_SECTOR_SIZE)))) {\n+ if (!(is_zero(bs, offset - head, head) &&\n+ is_zero(bs, offset + bytes,\n+ tail ? s->cluster_size - tail : 0))) {\n return -ENOTSUP;\n }\n\n qemu_co_mutex_lock(&s->lock);\n /* We can have new write after previous check */\n- offset = cl_start << BDRV_SECTOR_BITS;\n+ offset = QEMU_ALIGN_DOWN(offset, s->cluster_size);\n bytes = s->cluster_size;\n nr = s->cluster_size;\n ret = qcow2_get_cluster_offset(bs, offset, &nr, &off);\n", "prefixes": [ "v4", "04/23" ] }