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GET /api/1.1/patches/2229022/?format=api
{ "id": 2229022, "url": "http://patchwork.ozlabs.org/api/1.1/patches/2229022/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260427170520.101242-2-kwolf@redhat.com/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/1.1/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": "" }, "msgid": "<20260427170520.101242-2-kwolf@redhat.com>", "date": "2026-04-27T17:05:17", "name": "[1/4] commit: Drain nodes across all of bdrv_commit()", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "dfeea151a4133a66301dfc0abf44f8578e9477f0", "submitter": { "id": 2714, "url": "http://patchwork.ozlabs.org/api/1.1/people/2714/?format=api", "name": "Kevin Wolf", "email": "kwolf@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260427170520.101242-2-kwolf@redhat.com/mbox/", "series": [ { "id": 501688, "url": "http://patchwork.ozlabs.org/api/1.1/series/501688/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=501688", "date": "2026-04-27T17:05:16", "name": "qcow2: Fix corruption on discard during write with COW", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/501688/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2229022/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2229022/checks/", "tags": {}, "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=dyUA6vP5;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists1p.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)" ], "Received": [ "from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g492b6JlXz1xvV\n\tfor <incoming@patchwork.ozlabs.org>; Tue, 28 Apr 2026 03:06:31 +1000 (AEST)", "from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces@nongnu.org>)\n\tid 1wHPP4-0007Zm-Fp; Mon, 27 Apr 2026 13:05:50 -0400", "from eggs.gnu.org ([2001:470:142:3::10])\n by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <kwolf@redhat.com>) id 1wHPP3-0007Yh-3m\n for qemu-devel@nongnu.org; Mon, 27 Apr 2026 13:05:49 -0400", "from us-smtp-delivery-124.mimecast.com ([170.10.129.124])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <kwolf@redhat.com>) id 1wHPP1-0006Rm-Mc\n for qemu-devel@nongnu.org; Mon, 27 Apr 2026 13:05:48 -0400", "from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com\n (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by\n relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n cipher=TLS_AES_256_GCM_SHA384) id us-mta-339-xeNFhFwbOXqFn5IM-6mYQQ-1; Mon,\n 27 Apr 2026 13:05:43 -0400", "from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com\n (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n (No client certificate requested)\n by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS\n id CF1251800609; Mon, 27 Apr 2026 17:05:41 +0000 (UTC)", "from merkur.fritz.box (unknown [10.44.49.22])\n by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP\n id 951A5180047F; Mon, 27 Apr 2026 17:05:39 +0000 (UTC)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1777309547;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=RNf7Qtsfx36oLLaeD/N/V5PatsHP0UT/LP0p18adqyc=;\n b=dyUA6vP5yOuy1t9xK/acm8c79iojvmzZQJeoKSuzR3r8x3t1B1l9Ws9wIFjUdtXzaE3LI1\n CXmMVQ6aEYtyXSEi0aa+BF2bv+XboYLW8ByyBVOLuTMi9Hph9b712qVfW63L41zn0kJKgl\n TYkEEqL3EI2xqUTjTlOSYKHvMdMrJUo=", "X-MC-Unique": "xeNFhFwbOXqFn5IM-6mYQQ-1", "X-Mimecast-MFC-AGG-ID": "xeNFhFwbOXqFn5IM-6mYQQ_1777309542", "From": "Kevin Wolf <kwolf@redhat.com>", "To": "qemu-block@nongnu.org", "Cc": "kwolf@redhat.com, hreitz@redhat.com, den@openvz.org, stefanha@redhat.com,\n qemu-stable@nongnu.org, qemu-devel@nongnu.org", "Subject": "[PATCH 1/4] commit: Drain nodes across all of bdrv_commit()", "Date": "Mon, 27 Apr 2026 19:05:17 +0200", "Message-ID": "<20260427170520.101242-2-kwolf@redhat.com>", "In-Reply-To": "<20260427170520.101242-1-kwolf@redhat.com>", "References": "<20260427170520.101242-1-kwolf@redhat.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Scanned-By": "MIMEDefang 3.4.1 on 10.30.177.111", "Received-SPF": "pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com", "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, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001,\n SPF_HELO_PASS=-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": "2.1.29", "Precedence": "list", "List-Id": "qemu development <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>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "The whole implementation of bdrv_commit() is only correct if no new\nwrites come in while it's running: It has only a single loop checking\nthe allocation status for each block and finally calls bdrv_make_empty()\nwithout checking if that throws away any new changes.\n\nWe already have to drain while taking the graph write lock. Just extend\nthe drained section to all of bdrv_commit() to make sure that we don't\nget any inconsistencies.\n\nSigned-off-by: Kevin Wolf <kwolf@redhat.com>\n---\n block/commit.c | 10 ++++++++--\n 1 file changed, 8 insertions(+), 2 deletions(-)", "diff": "diff --git a/block/commit.c b/block/commit.c\nindex 0d9e1a16d7a..c5e3ef03a21 100644\n--- a/block/commit.c\n+++ b/block/commit.c\n@@ -518,6 +518,7 @@ int bdrv_commit(BlockDriverState *bs)\n if (!drv)\n return -ENOMEDIUM;\n \n+ bdrv_drain_all_begin();\n bdrv_graph_rdlock_main_loop();\n \n backing_file_bs = bdrv_cow_bs(bs);\n@@ -549,6 +550,10 @@ int bdrv_commit(BlockDriverState *bs)\n BLK_PERM_ALL);\n backing = blk_new(ctx, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);\n \n+ /* We drained all nodes, but still make requests through BlockBackends */\n+ blk_set_disable_request_queuing(src, true);\n+ blk_set_disable_request_queuing(backing, true);\n+\n ret = blk_insert_bs(src, bs, &local_err);\n if (ret < 0) {\n error_report_err(local_err);\n@@ -565,7 +570,7 @@ int bdrv_commit(BlockDriverState *bs)\n \n bdrv_graph_rdunlock_main_loop();\n \n- bdrv_graph_wrlock_drained();\n+ bdrv_graph_wrlock();\n bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort);\n bdrv_set_backing_hd(bs, commit_top_bs, &error_abort);\n bdrv_graph_wrunlock();\n@@ -647,7 +652,7 @@ ro_cleanup:\n blk_unref(backing);\n \n bdrv_graph_rdunlock_main_loop();\n- bdrv_graph_wrlock_drained();\n+ bdrv_graph_wrlock();\n if (bdrv_cow_bs(bs) != backing_file_bs) {\n bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);\n }\n@@ -663,6 +668,7 @@ ro_cleanup:\n \n out:\n bdrv_graph_rdunlock_main_loop();\n+ bdrv_drain_all_end();\n \n return ret;\n }\n", "prefixes": [ "1/4" ] }