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GET /api/patches/1307017/?format=api
{ "id": 1307017, "url": "http://patchwork.ozlabs.org/api/patches/1307017/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/402a16641f750c1069e0926c454f1da7b2eca10b.1591801197.git.berto@igalia.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": "<402a16641f750c1069e0926c454f1da7b2eca10b.1591801197.git.berto@igalia.com>", "list_archive_url": null, "date": "2020-06-10T15:03:01", "name": "[v8,23/34] qcow2: Add subcluster support to discard_in_l2_slice()", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "892821a52f95da7b1d34b566135e7595abf4c8f3", "submitter": { "id": 65704, "url": "http://patchwork.ozlabs.org/api/people/65704/?format=api", "name": "Alberto Garcia", "email": "berto@igalia.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/402a16641f750c1069e0926c454f1da7b2eca10b.1591801197.git.berto@igalia.com/mbox/", "series": [ { "id": 182563, "url": "http://patchwork.ozlabs.org/api/series/182563/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=182563", "date": "2020-06-10T15:02:49", "name": "Add subcluster allocation to qcow2", "version": 8, "mbox": "http://patchwork.ozlabs.org/series/182563/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/1307017/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/1307017/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 spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=<UNKNOWN>)", "ozlabs.org;\n dmarc=none (p=none dis=none) header.from=igalia.com", "ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256\n header.s=20170329 header.b=Gr5+q/YR;\n\tdkim-atps=neutral" ], "Received": [ "from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 49hrDZ0Yrcz9sQx\n\tfor <incoming@patchwork.ozlabs.org>; Thu, 11 Jun 2020 01:16:30 +1000 (AEST)", "from localhost ([::1]:57054 helo=lists1p.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>)\n\tid 1jj2Sp-00027T-N0\n\tfor incoming@patchwork.ozlabs.org; Wed, 10 Jun 2020 11:16:27 -0400", "from eggs.gnu.org ([2001:470:142:3::10]:36142)\n by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <berto@igalia.com>)\n id 1jj2Gv-0002gd-IN; Wed, 10 Jun 2020 11:04:09 -0400", "from fanzine.igalia.com ([178.60.130.6]:58130)\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128)\n (Exim 4.90_1) (envelope-from <berto@igalia.com>)\n id 1jj2Gr-0006wD-FP; Wed, 10 Jun 2020 11:04:08 -0400", "from [81.0.38.199] (helo=perseus.local)\n by fanzine.igalia.com with esmtpsa\n (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim)\n id 1jj2GR-0007h7-Jp; Wed, 10 Jun 2020 17:03:39 +0200", "from berto by perseus.local with local (Exim 4.92)\n (envelope-from <berto@igalia.com>)\n id 1jj2GC-0007NT-BL; Wed, 10 Jun 2020 17:03:24 +0200" ], "DKIM-Signature": "v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com;\n s=20170329;\n h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From;\n bh=wwP+F61UHuBD2MYWJK+ZYjI142FX+Mf725oBfkWGky0=;\n b=Gr5+q/YR5Qtn1aQNXbzPMc0bF3iA+k7xsybnQlVTWyPRyKfl8SY1hPIq4kKiNGyDvSuS3ux429tlYtOKYjoQjQsCACdiyZ1dBr6PzSeRcRsQ/92Ng8BNvw65YJgK/xP8kP2BQJ69Yvuwsp5WyVmJXsqma4iopB82WBm95fS9xixvm6l2FvbvZ5dVDTyqN7Xh3OYZdrCiZNViWg2bfLIBndauZMi8chFCi7PUQC5RZju4FnYB1a+rv8ohOgLUVm0A72jiyJzP96/f9cqulzwy+LHedRcxgryNgeDJtA2POUQxurESpvUVtEHBgEllbkjl0Sq2iC9YdqN+/X2VuB/uug==;", "From": "Alberto Garcia <berto@igalia.com>", "To": "qemu-devel@nongnu.org", "Subject": "[PATCH v8 23/34] qcow2: Add subcluster support to\n discard_in_l2_slice()", "Date": "Wed, 10 Jun 2020 17:03:01 +0200", "Message-Id": "\n <402a16641f750c1069e0926c454f1da7b2eca10b.1591801197.git.berto@igalia.com>", "X-Mailer": "git-send-email 2.20.1", "In-Reply-To": "<cover.1591801197.git.berto@igalia.com>", "References": "<cover.1591801197.git.berto@igalia.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Received-SPF": "pass client-ip=178.60.130.6; envelope-from=berto@igalia.com;\n helo=fanzine.igalia.com", "X-detected-operating-system": "by eggs.gnu.org: First seen = 2020/06/10 11:03:39", "X-ACL-Warn": "Detected OS = Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy]", "X-Spam_score_int": "-20", "X-Spam_score": "-2.1", "X-Spam_bar": "--", "X-Spam_report": "(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=_AUTOLEARN", "X-Spam_action": "no action", "X-BeenThere": "qemu-devel@nongnu.org", "X-Mailman-Version": "2.1.23", "Precedence": "list", "List-Id": "<qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://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 <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Cc": "Kevin Wolf <kwolf@redhat.com>,\n Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,\n Alberto Garcia <berto@igalia.com>, qemu-block@nongnu.org,\n Derek Su <dereksu@qnap.com>, Max Reitz <mreitz@redhat.com>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "\"Qemu-devel\"\n <qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>" }, "content": "Two things need to be taken into account here:\n\n1) With full_discard == true the L2 entry must be cleared completely.\n This also includes the L2 bitmap if the image has extended L2\n entries.\n\n2) With full_discard == false we have to make the discarded cluster\n read back as zeroes. With normal L2 entries this is done with the\n QCOW_OFLAG_ZERO bit, whereas with extended L2 entries this is done\n with the individual 'all zeroes' bits for each subcluster.\n\n Note however that QCOW_OFLAG_ZERO is not supported in v2 qcow2\n images so, if there is a backing file, discard cannot guarantee\n that the image will read back as zeroes. If this is important for\n the caller it should forbid it as qcow2_co_pdiscard() does (see\n 80f5c01183 for more details).\n\nSigned-off-by: Alberto Garcia <berto@igalia.com>\nReviewed-by: Eric Blake <eblake@redhat.com>\n---\n block/qcow2-cluster.c | 52 +++++++++++++++++++------------------------\n 1 file changed, 23 insertions(+), 29 deletions(-)", "diff": "diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c\nindex 4e59bbd545..edfc8ea91c 100644\n--- a/block/qcow2-cluster.c\n+++ b/block/qcow2-cluster.c\n@@ -1847,11 +1847,17 @@ static int discard_in_l2_slice(BlockDriverState *bs, uint64_t offset,\n assert(nb_clusters <= INT_MAX);\n \n for (i = 0; i < nb_clusters; i++) {\n- uint64_t old_l2_entry;\n-\n- old_l2_entry = get_l2_entry(s, l2_slice, l2_index + i);\n+ uint64_t old_l2_entry = get_l2_entry(s, l2_slice, l2_index + i);\n+ uint64_t old_l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i);\n+ uint64_t new_l2_entry = old_l2_entry;\n+ uint64_t new_l2_bitmap = old_l2_bitmap;\n+ QCow2ClusterType cluster_type =\n+ qcow2_get_cluster_type(bs, old_l2_entry);\n \n /*\n+ * If full_discard is true, the cluster should not read back as zeroes,\n+ * but rather fall through to the backing file.\n+ *\n * If full_discard is false, make sure that a discarded area reads back\n * as zeroes for v3 images (we cannot do it for v2 without actually\n * writing a zero-filled buffer). We can skip the operation if the\n@@ -1860,40 +1866,28 @@ static int discard_in_l2_slice(BlockDriverState *bs, uint64_t offset,\n *\n * TODO We might want to use bdrv_block_status(bs) here, but we're\n * holding s->lock, so that doesn't work today.\n- *\n- * If full_discard is true, the sector should not read back as zeroes,\n- * but rather fall through to the backing file.\n */\n- switch (qcow2_get_cluster_type(bs, old_l2_entry)) {\n- case QCOW2_CLUSTER_UNALLOCATED:\n- if (full_discard || !bs->backing) {\n- continue;\n+ if (full_discard) {\n+ new_l2_entry = new_l2_bitmap = 0;\n+ } else if (bs->backing || qcow2_cluster_is_allocated(cluster_type)) {\n+ if (has_subclusters(s)) {\n+ new_l2_entry = 0;\n+ new_l2_bitmap = QCOW_L2_BITMAP_ALL_ZEROES;\n+ } else {\n+ new_l2_entry = s->qcow_version >= 3 ? QCOW_OFLAG_ZERO : 0;\n }\n- break;\n+ }\n \n- case QCOW2_CLUSTER_ZERO_PLAIN:\n- if (!full_discard) {\n- continue;\n- }\n- break;\n-\n- case QCOW2_CLUSTER_ZERO_ALLOC:\n- case QCOW2_CLUSTER_NORMAL:\n- case QCOW2_CLUSTER_COMPRESSED:\n- break;\n-\n- default:\n- abort();\n+ if (old_l2_entry == new_l2_entry && old_l2_bitmap == new_l2_bitmap) {\n+ continue;\n }\n \n /* First remove L2 entries */\n qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);\n- if (!full_discard && s->qcow_version >= 3) {\n- set_l2_entry(s, l2_slice, l2_index + i, QCOW_OFLAG_ZERO);\n- } else {\n- set_l2_entry(s, l2_slice, l2_index + i, 0);\n+ set_l2_entry(s, l2_slice, l2_index + i, new_l2_entry);\n+ if (has_subclusters(s)) {\n+ set_l2_bitmap(s, l2_slice, l2_index + i, new_l2_bitmap);\n }\n-\n /* Then decrease the refcount */\n qcow2_free_any_clusters(bs, old_l2_entry, 1, type);\n }\n", "prefixes": [ "v8", "23/34" ] }