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[PULL 03/34] qcow2: Add calculate_l2_meta()
From: |
Max Reitz |
Subject: |
[PULL 03/34] qcow2: Add calculate_l2_meta() |
Date: |
Tue, 25 Aug 2020 10:32:40 +0200 |
From: Alberto Garcia <berto@igalia.com>
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 <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id:
<e5bc4a648dac31972bfa7a0e554be8064be78799.1594396418.git.berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
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:
--
2.26.2
- [PULL 00/34] Block patches, Max Reitz, 2020/08/25
- [PULL 01/34] qcow2: Make Qcow2AioTask store the full host offset, Max Reitz, 2020/08/25
- [PULL 02/34] qcow2: Convert qcow2_get_cluster_offset() into qcow2_get_host_offset(), Max Reitz, 2020/08/25
- [PULL 03/34] qcow2: Add calculate_l2_meta(),
Max Reitz <=
- [PULL 04/34] qcow2: Split cluster_needs_cow() out of count_cow_clusters(), Max Reitz, 2020/08/25
- [PULL 05/34] qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in handle_copied(), Max Reitz, 2020/08/25
- [PULL 06/34] qcow2: Add get_l2_entry() and set_l2_entry(), Max Reitz, 2020/08/25
- [PULL 07/34] qcow2: Document the Extended L2 Entries feature, Max Reitz, 2020/08/25
- [PULL 09/34] qcow2: Add subcluster-related fields to BDRVQcow2State, Max Reitz, 2020/08/25
- [PULL 10/34] qcow2: Add offset_to_sc_index(), Max Reitz, 2020/08/25
- [PULL 11/34] qcow2: Add offset_into_subcluster() and size_to_subclusters(), Max Reitz, 2020/08/25
- [PULL 12/34] qcow2: Add l2_entry_size(), Max Reitz, 2020/08/25
- [PULL 13/34] qcow2: Update get/set_l2_entry() and add get/set_l2_bitmap(), Max Reitz, 2020/08/25
- [PULL 08/34] qcow2: Add dummy has_subclusters() function, Max Reitz, 2020/08/25