From nobody Mon Feb 9 21:40:27 2026 Delivered-To: importer@patchew.org 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; 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=1584470440; cv=none; d=zohomail.com; s=zohoarc; b=OU0tAexHytiG+DtGkGxNicvbMC1YpDrFvPdS2+su/fA+l2OLGvNAxvhsQIuduK3NSGZXh+Vg4uOdCTBm5kn0My00JKj2UoG3x6pYGDqBlII+vlZ6J7axlZ8GMEg249QaF4Z3EuRCkKNhPSB/xYllStF8FTrL4d6Y7SjxMnMOccU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1584470440; 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=snU5YlWGDhrk8dD7MLwe4YRhknZ6d9pa8+zu7OhWw2g=; b=ciDTUkqHMMcX6ft9WT6XG/H0iRXeo/lE9YMIP8YOznW7M9M4qg4Dppczq4fk5yU2fBOKPPdLWDIcuLQykpX78WtKhFyLQskkXQaRq0K4sf7UXpuvb2R9o4SuKJKCQai6aexSNCAnjo/uosTQbwq9/PiVjl6ow9Zo0sb0v6QrU1k= 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 1584470440232491.7889420980091; Tue, 17 Mar 2020 11:40:40 -0700 (PDT) Received: from localhost ([::1]:39600 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEH8p-0003jA-13 for importer@patchew.org; Tue, 17 Mar 2020 14:40:39 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48957) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEGn0-0003at-BD for qemu-devel@nongnu.org; Tue, 17 Mar 2020 14:18:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jEGmv-00009D-7B for qemu-devel@nongnu.org; Tue, 17 Mar 2020 14:18:06 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:58055) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1jEGmu-000650-9O; Tue, 17 Mar 2020 14:18:01 -0400 Received: from [81.0.35.138] (helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1jEGmD-000153-30; Tue, 17 Mar 2020 19:17:17 +0100 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1jEGlw-0006Ob-KF; Tue, 17 Mar 2020 19:17:00 +0100 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=snU5YlWGDhrk8dD7MLwe4YRhknZ6d9pa8+zu7OhWw2g=; b=FZcmKTHssrqx+j+Urw0N1CIWV32YMVWaik4Y5G8mueB6LST4mZq/BvfIOCnBYxi25KvEObsGrIzMvDc6X6ikj5SxS174+sNV0BMPmfBwfblxerhBZSvCzbrXiKz/ph+TsEAkePLkP5dLxMT5KOVFg5vqRXj2vOIE1qqtMZLPf+fJu3Eue+/pyWWQAZtf3RhDZrWoIpZnCxNCfV2+AG9Jfu2/SFUzl7a4Uubr8ZH6iXS4AU8d4p4r8/7tsX1yPxIg9oco6LUoO5gnvPTRPlZ89CaYeWYBS1bru3AVle+bkgE+so8UaO6xmQHjRnC3YV/Bb8R4iU+SwG24fOns9nSsqA==; From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [PATCH v4 17/30] qcow2: Add subcluster support to calculate_l2_meta() Date: Tue, 17 Mar 2020 19:16:14 +0100 Message-Id: <6f179204ed9ab6274a9d30b6aa9a63865a16035a.1584468723.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 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Received-From: 178.60.130.6 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 , Anton Nefedov , Alberto Garcia , qemu-block@nongnu.org, Max Reitz , Vladimir Sementsov-Ogievskiy , "Denis V . Lunev" 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" If an image has subclusters then there are more copy-on-write scenarios that we need to consider. Let's say we have a write request from the middle of subcluster #3 until the end of the cluster: - If the cluster is new, then subclusters #0 to #3 from the old cluster must be copied into the new one. - If the cluster is new but the old cluster was unallocated, then only subcluster #3 needs copy-on-write. #0 to #2 are marked as unallocated in the bitmap of the new L2 entry. - If we are overwriting an old cluster and subcluster #3 is unallocated or has the all-zeroes bit set then we need copy-on-write on subcluster #3. - If we are overwriting an old cluster and subcluster #3 was allocated then there is no need to copy-on-write. Signed-off-by: Alberto Garcia Reviewed-by: Max Reitz Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/qcow2-cluster.c | 140 +++++++++++++++++++++++++++++++++--------- 1 file changed, 110 insertions(+), 30 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 8cdf8a23b6..c6f3cc9237 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1061,56 +1061,128 @@ void qcow2_alloc_cluster_abort(BlockDriverState *b= s, QCowL2Meta *m) * If @keep_old is true it means that the clusters were already * allocated and will be overwritten. If false then the clusters are * new and we have to decrease the reference count of the old ones. + * + * Returns 1 on success, -errno on failure (in order to match the + * return value of handle_copied() and handle_alloc()). */ -static void calculate_l2_meta(BlockDriverState *bs, - uint64_t host_cluster_offset, - uint64_t guest_offset, unsigned bytes, - uint64_t *l2_slice, QCowL2Meta **m, bool kee= p_old) +static int calculate_l2_meta(BlockDriverState *bs, uint64_t host_cluster_o= ffset, + uint64_t guest_offset, unsigned bytes, + uint64_t *l2_slice, QCowL2Meta **m, bool keep= _old) { BDRVQcow2State *s =3D bs->opaque; - int l2_index =3D offset_to_l2_slice_index(s, guest_offset); - uint64_t l2_entry; + int sc_index, l2_index =3D offset_to_l2_slice_index(s, guest_offset); + uint64_t l2_entry, l2_bitmap; unsigned cow_start_from, cow_end_to; unsigned cow_start_to =3D offset_into_cluster(s, guest_offset); unsigned cow_end_from =3D cow_start_to + bytes; unsigned nb_clusters =3D size_to_clusters(s, cow_end_from); QCowL2Meta *old_m =3D *m; - QCow2ClusterType type; + QCow2SubclusterType type; =20 assert(nb_clusters <=3D s->l2_slice_size - l2_index); =20 - /* Return if there's no COW (all clusters are normal and we keep them)= */ + /* Return if there's no COW (all subclusters are normal and we are + * keeping the clusters) */ if (keep_old) { + unsigned first_sc =3D cow_start_to / s->subcluster_size; + unsigned last_sc =3D (cow_end_from - 1) / s->subcluster_size; int i; - for (i =3D 0; i < nb_clusters; i++) { - l2_entry =3D get_l2_entry(s, l2_slice, l2_index + i); - if (qcow2_get_cluster_type(bs, l2_entry) !=3D QCOW2_CLUSTER_NO= RMAL) { + for (i =3D first_sc; i <=3D last_sc; i++) { + unsigned c =3D i / s->subclusters_per_cluster; + unsigned sc =3D i % s->subclusters_per_cluster; + l2_entry =3D get_l2_entry(s, l2_slice, l2_index + c); + l2_bitmap =3D get_l2_bitmap(s, l2_slice, l2_index + c); + type =3D qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc= ); + if (type =3D=3D QCOW2_SUBCLUSTER_INVALID) { + l2_index +=3D c; /* Point to the invalid entry */ + goto fail; + } + if (type !=3D QCOW2_SUBCLUSTER_NORMAL) { break; } } - if (i =3D=3D nb_clusters) { - return; + if (i =3D=3D last_sc + 1) { + return 1; } } =20 /* Get the L2 entry of the first cluster */ l2_entry =3D get_l2_entry(s, l2_slice, l2_index); - type =3D qcow2_get_cluster_type(bs, l2_entry); + l2_bitmap =3D get_l2_bitmap(s, l2_slice, l2_index); + sc_index =3D offset_to_sc_index(s, guest_offset); + type =3D qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index); =20 - if (type =3D=3D QCOW2_CLUSTER_NORMAL && keep_old) { - cow_start_from =3D cow_start_to; + if (type =3D=3D QCOW2_SUBCLUSTER_INVALID) { + goto fail; + } + + if (!keep_old) { + switch (type) { + case QCOW2_SUBCLUSTER_NORMAL: + case QCOW2_SUBCLUSTER_COMPRESSED: + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + cow_start_from =3D 0; + break; + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: + cow_start_from =3D sc_index << s->subcluster_bits; + break; + default: + g_assert_not_reached(); + } } else { - cow_start_from =3D 0; + switch (type) { + case QCOW2_SUBCLUSTER_NORMAL: + cow_start_from =3D cow_start_to; + break; + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + cow_start_from =3D sc_index << s->subcluster_bits; + break; + default: + g_assert_not_reached(); + } } =20 /* Get the L2 entry of the last cluster */ - l2_entry =3D get_l2_entry(s, l2_slice, l2_index + nb_clusters - 1); - type =3D qcow2_get_cluster_type(bs, l2_entry); + l2_index +=3D nb_clusters - 1; + l2_entry =3D get_l2_entry(s, l2_slice, l2_index); + l2_bitmap =3D get_l2_bitmap(s, l2_slice, l2_index); + sc_index =3D offset_to_sc_index(s, guest_offset + bytes - 1); + type =3D qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index); =20 - if (type =3D=3D QCOW2_CLUSTER_NORMAL && keep_old) { - cow_end_to =3D cow_end_from; + if (type =3D=3D QCOW2_SUBCLUSTER_INVALID) { + goto fail; + } + + if (!keep_old) { + switch (type) { + case QCOW2_SUBCLUSTER_NORMAL: + case QCOW2_SUBCLUSTER_COMPRESSED: + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + cow_end_to =3D ROUND_UP(cow_end_from, s->cluster_size); + break; + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: + cow_end_to =3D ROUND_UP(cow_end_from, s->subcluster_size); + break; + default: + g_assert_not_reached(); + } } else { - cow_end_to =3D ROUND_UP(cow_end_from, s->cluster_size); + switch (type) { + case QCOW2_SUBCLUSTER_NORMAL: + cow_end_to =3D cow_end_from; + break; + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + cow_end_to =3D ROUND_UP(cow_end_from, s->subcluster_size); + break; + default: + g_assert_not_reached(); + } } =20 *m =3D g_malloc0(sizeof(**m)); @@ -1135,6 +1207,18 @@ static void calculate_l2_meta(BlockDriverState *bs, =20 qemu_co_queue_init(&(*m)->dependent_requests); QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); + +fail: + if (type =3D=3D QCOW2_SUBCLUSTER_INVALID) { + uint64_t l1_index =3D offset_to_l1_index(s, guest_offset); + uint64_t l2_offset =3D s->l1_table[l1_index] & L1E_OFFSET_MASK; + qcow2_signal_corruption(bs, true, -1, -1, "Invalid cluster entry f= ound " + " (L2 offset: %#" PRIx64 ", L2 index: %#x)= ", + l2_offset, l2_index); + return -EIO; + } + + return 1; } =20 /* @@ -1352,10 +1436,8 @@ static int handle_copied(BlockDriverState *bs, uint6= 4_t guest_offset, - offset_into_cluster(s, guest_offset)); assert(*bytes !=3D 0); =20 - calculate_l2_meta(bs, cluster_offset & L2E_OFFSET_MASK, guest_offs= et, - *bytes, l2_slice, m, true); - - ret =3D 1; + ret =3D calculate_l2_meta(bs, cluster_offset & L2E_OFFSET_MASK, + guest_offset, *bytes, l2_slice, m, true); } else { ret =3D 0; } @@ -1530,10 +1612,8 @@ static int handle_alloc(BlockDriverState *bs, uint64= _t guest_offset, *bytes =3D MIN(*bytes, nb_bytes - offset_into_cluster(s, guest_offset)= ); assert(*bytes !=3D 0); =20 - calculate_l2_meta(bs, alloc_cluster_offset, guest_offset, *bytes, l2_s= lice, - m, false); - - ret =3D 1; + ret =3D calculate_l2_meta(bs, alloc_cluster_offset, guest_offset, *byt= es, + l2_slice, m, false); =20 out: qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice); --=20 2.20.1