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Tue, 25 Aug 2020 08:33:20 +0000 (UTC) Received: from localhost (ovpn-113-72.ams2.redhat.com [10.36.113.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 23B0A19144; Tue, 25 Aug 2020 08:33:19 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 03/34] qcow2: Add calculate_l2_meta() Date: Tue, 25 Aug 2020 10:32:40 +0200 Message-Id: <20200825083311.1098442-4-mreitz@redhat.com> In-Reply-To: <20200825083311.1098442-1-mreitz@redhat.com> References: <20200825083311.1098442-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=mreitz@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/25 02:05:08 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.956, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no 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 , Peter Maydell , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Alberto Garcia handle_alloc() creates a QCowL2Meta structure in order to update the image metadata and perform the necessary copy-on-write operations. This patch moves that code to a separate function so it can be used from other places. Signed-off-by: Alberto Garcia Reviewed-by: Max Reitz Message-Id: Signed-off-by: Max Reitz --- block/qcow2-cluster.c | 77 +++++++++++++++++++++++++++++-------------- 1 file changed, 53 insertions(+), 24 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 71ddb0c462..6447222ba0 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1038,6 +1038,56 @@ void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m) } } +/* + * For a given write request, create a new QCowL2Meta structure, add + * it to @m and the BDRVQcow2State.cluster_allocs list. + * + * @host_cluster_offset points to the beginning of the first cluster. + * + * @guest_offset and @bytes indicate the offset and length of the + * request. + * + * 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. + */ +static void calculate_l2_meta(BlockDriverState *bs, + uint64_t host_cluster_offset, + uint64_t guest_offset, unsigned bytes, + QCowL2Meta **m, bool keep_old) +{ + BDRVQcow2State *s = bs->opaque; + unsigned cow_start_from = 0; + unsigned cow_start_to = offset_into_cluster(s, guest_offset); + unsigned cow_end_from = cow_start_to + bytes; + unsigned cow_end_to = ROUND_UP(cow_end_from, s->cluster_size); + unsigned nb_clusters = size_to_clusters(s, cow_end_from); + QCowL2Meta *old_m = *m; + + *m = g_malloc0(sizeof(**m)); + **m = (QCowL2Meta) { + .next = old_m, + + .alloc_offset = host_cluster_offset, + .offset = start_of_cluster(s, guest_offset), + .nb_clusters = nb_clusters, + + .keep_old_clusters = keep_old, + + .cow_start = { + .offset = cow_start_from, + .nb_bytes = cow_start_to - cow_start_from, + }, + .cow_end = { + .offset = cow_end_from, + .nb_bytes = cow_end_to - cow_end_from, + }, + }; + + qemu_co_queue_init(&(*m)->dependent_requests); + QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); +} + /* * Returns the number of contiguous clusters that can be used for an allocating * write, but require COW to be performed (this includes yet unallocated space, @@ -1436,35 +1486,14 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, uint64_t requested_bytes = *bytes + offset_into_cluster(s, guest_offset); int avail_bytes = nb_clusters << s->cluster_bits; int nb_bytes = MIN(requested_bytes, avail_bytes); - QCowL2Meta *old_m = *m; - - *m = g_malloc0(sizeof(**m)); - - **m = (QCowL2Meta) { - .next = old_m, - - .alloc_offset = alloc_cluster_offset, - .offset = start_of_cluster(s, guest_offset), - .nb_clusters = nb_clusters, - - .keep_old_clusters = keep_old_clusters, - - .cow_start = { - .offset = 0, - .nb_bytes = offset_into_cluster(s, guest_offset), - }, - .cow_end = { - .offset = nb_bytes, - .nb_bytes = avail_bytes - nb_bytes, - }, - }; - qemu_co_queue_init(&(*m)->dependent_requests); - QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); *host_offset = alloc_cluster_offset + offset_into_cluster(s, 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, + m, keep_old_clusters); + return 1; fail: