From patchwork Tue Mar 17 18:16:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 1256823 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=igalia.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256 header.s=20170329 header.b=FZcmKTHs; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 48hhmb0k5pz9sP7 for ; Wed, 18 Mar 2020 05:39:59 +1100 (AEDT) Received: from localhost ([::1]:39570 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEH89-0002QS-0X for incoming@patchwork.ozlabs.org; Tue, 17 Mar 2020 14:39:57 -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 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==; 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 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 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" 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 *bs, 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 keep_old) +static int calculate_l2_meta(BlockDriverState *bs, uint64_t host_cluster_offset, + uint64_t guest_offset, unsigned bytes, + uint64_t *l2_slice, QCowL2Meta **m, bool keep_old) { BDRVQcow2State *s = bs->opaque; - int l2_index = offset_to_l2_slice_index(s, guest_offset); - uint64_t l2_entry; + int sc_index, l2_index = 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 = offset_into_cluster(s, guest_offset); unsigned cow_end_from = cow_start_to + bytes; unsigned nb_clusters = size_to_clusters(s, cow_end_from); QCowL2Meta *old_m = *m; - QCow2ClusterType type; + QCow2SubclusterType type; assert(nb_clusters <= s->l2_slice_size - l2_index); - /* 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 = cow_start_to / s->subcluster_size; + unsigned last_sc = (cow_end_from - 1) / s->subcluster_size; int i; - for (i = 0; i < nb_clusters; i++) { - l2_entry = get_l2_entry(s, l2_slice, l2_index + i); - if (qcow2_get_cluster_type(bs, l2_entry) != QCOW2_CLUSTER_NORMAL) { + for (i = first_sc; i <= last_sc; i++) { + unsigned c = i / s->subclusters_per_cluster; + unsigned sc = i % s->subclusters_per_cluster; + l2_entry = get_l2_entry(s, l2_slice, l2_index + c); + l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + c); + type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc); + if (type == QCOW2_SUBCLUSTER_INVALID) { + l2_index += c; /* Point to the invalid entry */ + goto fail; + } + if (type != QCOW2_SUBCLUSTER_NORMAL) { break; } } - if (i == nb_clusters) { - return; + if (i == last_sc + 1) { + return 1; } } /* Get the L2 entry of the first cluster */ l2_entry = get_l2_entry(s, l2_slice, l2_index); - type = qcow2_get_cluster_type(bs, l2_entry); + l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index); + sc_index = offset_to_sc_index(s, guest_offset); + type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index); - if (type == QCOW2_CLUSTER_NORMAL && keep_old) { - cow_start_from = cow_start_to; + if (type == 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 = 0; + break; + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: + cow_start_from = sc_index << s->subcluster_bits; + break; + default: + g_assert_not_reached(); + } } else { - cow_start_from = 0; + switch (type) { + case QCOW2_SUBCLUSTER_NORMAL: + cow_start_from = cow_start_to; + break; + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + cow_start_from = sc_index << s->subcluster_bits; + break; + default: + g_assert_not_reached(); + } } /* Get the L2 entry of the last cluster */ - l2_entry = get_l2_entry(s, l2_slice, l2_index + nb_clusters - 1); - type = qcow2_get_cluster_type(bs, l2_entry); + l2_index += nb_clusters - 1; + l2_entry = get_l2_entry(s, l2_slice, l2_index); + l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index); + sc_index = offset_to_sc_index(s, guest_offset + bytes - 1); + type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index); - if (type == QCOW2_CLUSTER_NORMAL && keep_old) { - cow_end_to = cow_end_from; + if (type == 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 = ROUND_UP(cow_end_from, s->cluster_size); + break; + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: + cow_end_to = ROUND_UP(cow_end_from, s->subcluster_size); + break; + default: + g_assert_not_reached(); + } } else { - cow_end_to = ROUND_UP(cow_end_from, s->cluster_size); + switch (type) { + case QCOW2_SUBCLUSTER_NORMAL: + cow_end_to = cow_end_from; + break; + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + cow_end_to = ROUND_UP(cow_end_from, s->subcluster_size); + break; + default: + g_assert_not_reached(); + } } *m = g_malloc0(sizeof(**m)); @@ -1135,6 +1207,18 @@ static void calculate_l2_meta(BlockDriverState *bs, qemu_co_queue_init(&(*m)->dependent_requests); QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); + +fail: + if (type == QCOW2_SUBCLUSTER_INVALID) { + uint64_t l1_index = offset_to_l1_index(s, guest_offset); + uint64_t l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK; + qcow2_signal_corruption(bs, true, -1, -1, "Invalid cluster entry found " + " (L2 offset: %#" PRIx64 ", L2 index: %#x)", + l2_offset, l2_index); + return -EIO; + } + + return 1; } /* @@ -1352,10 +1436,8 @@ static int handle_copied(BlockDriverState *bs, uint64_t guest_offset, - offset_into_cluster(s, guest_offset)); assert(*bytes != 0); - calculate_l2_meta(bs, cluster_offset & L2E_OFFSET_MASK, guest_offset, - *bytes, l2_slice, m, true); - - ret = 1; + ret = calculate_l2_meta(bs, cluster_offset & L2E_OFFSET_MASK, + guest_offset, *bytes, l2_slice, m, true); } else { ret = 0; } @@ -1530,10 +1612,8 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, *bytes = MIN(*bytes, nb_bytes - offset_into_cluster(s, guest_offset)); assert(*bytes != 0); - calculate_l2_meta(bs, alloc_cluster_offset, guest_offset, *bytes, l2_slice, - m, false); - - ret = 1; + ret = calculate_l2_meta(bs, alloc_cluster_offset, guest_offset, *bytes, + l2_slice, m, false); out: qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);