From nobody Mon Feb 9 03:14:04 2026 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 ARC-Seal: i=1; a=rsa-sha256; t=1593342723; cv=none; d=zohomail.com; s=zohoarc; b=aRGt+NvgzX6pytrsx1JDaHO2jdg4dfQ3FH73g2vEKxvIw65nqntibosJ/2OGNqigqD451CG8SwobvK5n4e45NDtJHXq/jXA2+MhM37ZnDkt/g4myRsrXJS2ukHnvNFOL1SdmOIbXe9UBa/zOPB8HtRHCDzIO2sc44Gf6wmZHA3A= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1593342723; h=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=77gOALnYBOSpWkq+ohxi6HDyy635WXZgxB4d2wUbhU8=; b=mes57R1a7Q0jRLzYpR7Cn8+LTgKPuJmuCtKyLAXWRDa4uUsCIAVDBV0Syps/8i3H4mg0Aqe2LtGlOvgBm9cYaz7wo87wJ/6Y5h3mmBXyTwwOhOFyWsXPK8abb4hBZoSncHBwlo/Z22ketNAfCX2tmsz7XaIgSxXxURtIUE8MWkE= ARC-Authentication-Results: i=1; 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 Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1593342723041443.7232386679799; Sun, 28 Jun 2020 04:12:03 -0700 (PDT) Received: from localhost ([::1]:44112 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jpVE9-0003pq-Mx for importer@patchew.org; Sun, 28 Jun 2020 07:12:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48438) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jpV6N-0007M2-Ld; Sun, 28 Jun 2020 07:03:59 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:42403) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jpV6J-0000XT-Sg; Sun, 28 Jun 2020 07:03:59 -0400 Received: from 26.red-79-158-236.dynamicip.rima-tde.net ([79.158.236.26] helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1jpV5Y-0002gn-Cg; Sun, 28 Jun 2020 13:03:09 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1jpV5I-000394-6O; Sun, 28 Jun 2020 13:02:52 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=77gOALnYBOSpWkq+ohxi6HDyy635WXZgxB4d2wUbhU8=; b=pjbciEeEmj5RAUsV+g6wPAJFEzBVkA19idYEZjJohZblRwyyTkSgCCxYNwotsNMbQftFsy8h+HLinCZv7fr+vwRmKV2L1L+KIr11gcM6xJob8ezphUwwqJgzcwlIeTd575ONOYbfEiUiWtLLbRbtxZ//+saAzouUfk83nKBFYXlbcVMctCM0yb5i1nLF1Jo2l95JwZcxFsjNvys9PEE39CNY88/SBAEjFryxxdtO8VD19KXyOIq5t8aRFtvVUMdpnF5/tFD1k6gPrue+spX9IOiqiXMAQn+xpxmsZv49Jh2oMHC0gXEmR15H0rw7iw3m9kMO8dLwdAKL5Uoj0qKZIA==; From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [PATCH v9 24/34] qcow2: Add subcluster support to check_refcounts_l2() Date: Sun, 28 Jun 2020 13:02:33 +0200 Message-Id: <8f424f702967348a6180cf4bc492d7ddede5ae57.1593342067.git.berto@igalia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 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=178.60.130.6; envelope-from=berto@igalia.com; helo=fanzine.igalia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/28 07:03:08 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, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , Alberto Garcia , qemu-block@nongnu.org, Derek Su , Max Reitz 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" The offset field of an uncompressed cluster's L2 entry must be aligned to the cluster size, otherwise it is invalid. If the cluster has no data then it means that the offset points to a preallocation, so we can clear the offset field without affecting the guest-visible data. This is what 'qemu-img check' does when run in repair mode. On traditional qcow2 images this can only happen when QCOW_OFLAG_ZERO is set, and repairing such entries turns the clusters from ZERO_ALLOC into ZERO_PLAIN. Extended L2 entries have no ZERO_ALLOC clusters and no QCOW_OFLAG_ZERO but the idea is the same: if none of the subclusters are allocated then we can clear the offset field and leave the bitmap untouched. Signed-off-by: Alberto Garcia Reviewed-by: Max Reitz --- block/qcow2-refcount.c | 16 +++++++++++----- tests/qemu-iotests/060.out | 2 +- 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 770c5dbc83..aae52607eb 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -1669,12 +1669,18 @@ static int check_refcounts_l2(BlockDriverState *bs,= BdrvCheckResult *res, =20 /* Correct offsets are cluster aligned */ if (offset_into_cluster(s, offset)) { + bool contains_data; res->corruptions++; =20 - if (qcow2_get_cluster_type(bs, l2_entry) =3D=3D - QCOW2_CLUSTER_ZERO_ALLOC) - { - fprintf(stderr, "%s offset=3D%" PRIx64 ": Preallocated= zero " + if (has_subclusters(s)) { + uint64_t l2_bitmap =3D get_l2_bitmap(s, l2_table, i); + contains_data =3D (l2_bitmap & QCOW_L2_BITMAP_ALL_ALLO= C); + } else { + contains_data =3D !(l2_entry & QCOW_OFLAG_ZERO); + } + + if (!contains_data) { + fprintf(stderr, "%s offset=3D%" PRIx64 ": Preallocated= " "cluster is not properly aligned; L2 entry " "corrupted.\n", fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", @@ -1686,7 +1692,7 @@ static int check_refcounts_l2(BlockDriverState *bs, B= drvCheckResult *res, int ign =3D active ? QCOW2_OL_ACTIVE_L2 : QCOW2_OL_INACTIVE_L2; =20 - l2_entry =3D QCOW_OFLAG_ZERO; + l2_entry =3D has_subclusters(s) ? 0 : QCOW_OFLAG_Z= ERO; set_l2_entry(s, l2_table, i, l2_entry); ret =3D qcow2_pre_write_overlap_check(bs, ign, l2e_offset, l2_entry_size(s), false); diff --git a/tests/qemu-iotests/060.out b/tests/qemu-iotests/060.out index be5f8707a3..fa3d68f0df 100644 --- a/tests/qemu-iotests/060.out +++ b/tests/qemu-iotests/060.out @@ -320,7 +320,7 @@ discard 65536/65536 bytes at offset 0 qcow2: Marking image as corrupt: Preallocated zero cluster offset 0x2a00 u= naligned (guest offset: 0); further corruption events will be suppressed write failed: Input/output error --- Repairing --- -Repairing offset=3D2a00: Preallocated zero cluster is not properly aligned= ; L2 entry corrupted. +Repairing offset=3D2a00: Preallocated cluster is not properly aligned; L2 = entry corrupted. The following inconsistencies were found and repaired: =20 0 leaked clusters --=20 2.20.1