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[PULL 04/34] qcow2: Split cluster_needs_cow() out of count_cow_clusters(
From: |
Max Reitz |
Subject: |
[PULL 04/34] qcow2: Split cluster_needs_cow() out of count_cow_clusters() |
Date: |
Tue, 25 Aug 2020 10:32:41 +0200 |
From: Alberto Garcia <berto@igalia.com>
We are going to need it in other places.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id:
<65e5d9627ca2ebe7e62deaeddf60949c33067d9d.1594396418.git.berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
block/qcow2-cluster.c | 34 +++++++++++++++++++---------------
1 file changed, 19 insertions(+), 15 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 6447222ba0..369689b27c 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1088,6 +1088,24 @@ static void calculate_l2_meta(BlockDriverState *bs,
QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
}
+/* Returns true if writing to a cluster requires COW */
+static bool cluster_needs_cow(BlockDriverState *bs, uint64_t l2_entry)
+{
+ switch (qcow2_get_cluster_type(bs, l2_entry)) {
+ case QCOW2_CLUSTER_NORMAL:
+ if (l2_entry & QCOW_OFLAG_COPIED) {
+ return false;
+ }
+ case QCOW2_CLUSTER_UNALLOCATED:
+ case QCOW2_CLUSTER_COMPRESSED:
+ case QCOW2_CLUSTER_ZERO_PLAIN:
+ case QCOW2_CLUSTER_ZERO_ALLOC:
+ return true;
+ default:
+ abort();
+ }
+}
+
/*
* 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,
@@ -1100,25 +1118,11 @@ static int count_cow_clusters(BlockDriverState *bs, int
nb_clusters,
for (i = 0; i < nb_clusters; i++) {
uint64_t l2_entry = be64_to_cpu(l2_slice[l2_index + i]);
- QCow2ClusterType cluster_type = qcow2_get_cluster_type(bs, l2_entry);
-
- switch(cluster_type) {
- case QCOW2_CLUSTER_NORMAL:
- if (l2_entry & QCOW_OFLAG_COPIED) {
- goto out;
- }
+ if (!cluster_needs_cow(bs, l2_entry)) {
break;
- case QCOW2_CLUSTER_UNALLOCATED:
- case QCOW2_CLUSTER_COMPRESSED:
- case QCOW2_CLUSTER_ZERO_PLAIN:
- case QCOW2_CLUSTER_ZERO_ALLOC:
- break;
- default:
- abort();
}
}
-out:
assert(i <= nb_clusters);
return i;
}
--
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, 2020/08/25
- [PULL 04/34] qcow2: Split cluster_needs_cow() out of count_cow_clusters(),
Max Reitz <=
- [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
- [PULL 15/34] qcow2: Add qcow2_get_subcluster_range_type(), Max Reitz, 2020/08/25