From nobody Mon Feb 9 12:11:17 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.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 (zoho.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=1571154520; cv=none; d=zoho.com; s=zohoarc; b=GQpZ7A2BZc1/bWKFcZMR1PXwAAPG/nRW7hDZflDPJUJ0dwl3BFW2oRgc51u9QCU0YW7hrEqBXZxAtvEdrDMHoW8Xafdic+16hDlpHMp8wWiSyzpLaNAauGaCvdTUm8PuM3ua0Ja7oN4yzQhUVD3SA745NHhr5FkaPl9ayJEXM64= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1571154520; 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=LyRBVk6DPKgZU3xdCKP6t9qXcnMtdtrOc91PUHA4dPc=; b=VhO+I9xnYwsIUcLv+y23NFKeJ9JWq575ejb8A7jIpm8PRxgyEw3gV1rt5kT5WaFy7AGVQC3afWKF+elFt9ppNwuKD1EZCdu4gu8uVmQfcIVujqHQeq6IDqPZqdnhk8b6nkR8fRloU6A+tT1P5O5nnXJ4d/tc2MC8Rl5V7VVptYY= ARC-Authentication-Results: i=1; mx.zoho.com; dkim=fail; spf=pass (zoho.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 1571154520521304.8490355080585; Tue, 15 Oct 2019 08:48:40 -0700 (PDT) Received: from localhost ([::1]:49326 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iKP3u-0005Qy-3a for importer@patchew.org; Tue, 15 Oct 2019 11:48:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48570) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iKOhN-0003Ov-51 for qemu-devel@nongnu.org; Tue, 15 Oct 2019 11:25:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iKOhK-0003sX-6G for qemu-devel@nongnu.org; Tue, 15 Oct 2019 11:25:20 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:47186) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1iKOhJ-0003cN-E1; Tue, 15 Oct 2019 11:25:18 -0400 Received: from 82-181-115-92.bb.dnainternet.fi ([82.181.115.92] helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1iKOge-0003aa-21; Tue, 15 Oct 2019 17:24:36 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1iKOfm-00061b-Te; Tue, 15 Oct 2019 18:23:42 +0300 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=LyRBVk6DPKgZU3xdCKP6t9qXcnMtdtrOc91PUHA4dPc=; b=N5+CnfJTTXGuI+IyvQKw6z2MrrVDoy6tA4UmRfQ1srOdw3CmNtCZV43sI9AYN5vQd82WLcGvPRDluvB/oBUM1DSHSCxBm9JZ7TjaVX5UU4bG97qmVGphOK9Xy7EYy5qsJTbHw7BbO5De0rhp0ujQzGNjOGlcfbJ5FHklmG4Q2eJueLCwcn0FY+H0+VVhcDVE6z3z6mqvE8bx1L6eDHry4ztXAYqlrllV/8Z56GbPN/lcKuVImELWON93OdKNqoibV83H8rj8uyFYVFEoLBmoFUYpcI53MA1rgz6fceQEOYnTf1MDpoce1icFIhtIqUzm4cnI67y0AIDiUyvmVJe0HQ==; From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [RFC PATCH 13/23] qcow2: Add subcluster support to calculate_l2_meta() Date: Tue, 15 Oct 2019 18:23:24 +0300 Message-Id: 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 , "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 --- block/qcow2-cluster.c | 136 +++++++++++++++++++++++++++++++++--------- 1 file changed, 108 insertions(+), 28 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 67f90e415d..8df0f67316 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1034,14 +1034,16 @@ 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. */ -static void calculate_l2_meta(BlockDriverState *bs, uint64_t host_offset, - uint64_t guest_offset, uint64_t bytes, - uint64_t *l2_slice, QCowL2Meta **m, bool kee= p_old) +static int calculate_l2_meta(BlockDriverState *bs, uint64_t host_offset, + uint64_t guest_offset, uint64_t 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; @@ -1049,38 +1051,108 @@ static void calculate_l2_meta(BlockDriverState *bs= , uint64_t host_offset, QCowL2Meta *old_m =3D *m; QCow2ClusterType type; =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_CLUSTER_INVALID) { + l2_index +=3D c; /* Point to the invalid entry */ + goto fail; + } + if (type !=3D QCOW2_CLUSTER_NORMAL) { break; } } - if (i =3D=3D nb_clusters) { - return; + if (i =3D=3D last_sc + 1) { + return 1; } } =20 /* Get the L2 entry from 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_CLUSTER_INVALID) { + goto fail; + } + + if (!keep_old) { + switch (type) { + case QCOW2_CLUSTER_NORMAL: + case QCOW2_CLUSTER_COMPRESSED: + case QCOW2_CLUSTER_ZERO_ALLOC: + case QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER: + cow_start_from =3D 0; + break; + case QCOW2_CLUSTER_ZERO_PLAIN: + case QCOW2_CLUSTER_UNALLOCATED: + 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_CLUSTER_NORMAL: + cow_start_from =3D cow_start_to; + break; + case QCOW2_CLUSTER_ZERO_ALLOC: + case QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER: + cow_start_from =3D sc_index << s->subcluster_bits; + break; + default: + g_assert_not_reached(); + } } =20 /* Get the L2 entry from 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_CLUSTER_INVALID) { + goto fail; + } + + if (!keep_old) { + switch (type) { + case QCOW2_CLUSTER_NORMAL: + case QCOW2_CLUSTER_COMPRESSED: + case QCOW2_CLUSTER_ZERO_ALLOC: + case QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER: + cow_end_to =3D ROUND_UP(cow_end_from, s->cluster_size); + break; + case QCOW2_CLUSTER_ZERO_PLAIN: + case QCOW2_CLUSTER_UNALLOCATED: + 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_CLUSTER_NORMAL: + cow_end_to =3D cow_end_from; + break; + case QCOW2_CLUSTER_ZERO_ALLOC: + case QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER: + 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)); @@ -1105,6 +1177,18 @@ static void calculate_l2_meta(BlockDriverState *bs, = uint64_t host_offset, =20 qemu_co_queue_init(&(*m)->dependent_requests); QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); + +fail: + if (type =3D=3D QCOW2_CLUSTER_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 /* Returns true if the cluster is unallocated or has refcount > 1 */ @@ -1313,10 +1397,8 @@ 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; } @@ -1488,10 +1570,8 @@ 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