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[RFC PATCH 02/23] qcow2: Split cluster_needs_cow() out of count_cow_clus
From: |
Alberto Garcia |
Subject: |
[RFC PATCH 02/23] qcow2: Split cluster_needs_cow() out of count_cow_clusters() |
Date: |
Tue, 15 Oct 2019 18:23:13 +0300 |
We are going to need it in other places.
Signed-off-by: Alberto Garcia <address@hidden>
---
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 fe2523ed66..f462e169c0 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1068,6 +1068,24 @@ static void calculate_l2_meta(BlockDriverState *bs,
uint64_t host_offset,
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,
@@ -1080,25 +1098,11 @@ 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;
}
--
2.20.1
- [RFC PATCH 12/23] qcow2: Handle QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER, (continued)
- [RFC PATCH 12/23] qcow2: Handle QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER, Alberto Garcia, 2019/10/15
- [RFC PATCH 09/23] qcow2: Add l2_entry_size(), Alberto Garcia, 2019/10/15
- [RFC PATCH 03/23] qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in handle_copied(), Alberto Garcia, 2019/10/15
- [RFC PATCH 05/23] qcow2: Document the Extended L2 Entries feature, Alberto Garcia, 2019/10/15
- [RFC PATCH 04/23] qcow2: Add get_l2_entry() and set_l2_entry(), Alberto Garcia, 2019/10/15
- [RFC PATCH 23/23] qcow2: Add the 'extended_l2' option and the QCOW2_INCOMPAT_EXTL2 bit, Alberto Garcia, 2019/10/15
- [RFC PATCH 11/23] qcow2: Add qcow2_get_subcluster_type(), Alberto Garcia, 2019/10/15
- [RFC PATCH 08/23] qcow2: Add offset_to_sc_index(), Alberto Garcia, 2019/10/15
- [RFC PATCH 19/23] qcow2: Fix offset calculation in handle_dependencies(), Alberto Garcia, 2019/10/15
- [RFC PATCH 02/23] qcow2: Split cluster_needs_cow() out of count_cow_clusters(),
Alberto Garcia <=
- [RFC PATCH 20/23] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2(), Alberto Garcia, 2019/10/15
- [RFC PATCH 18/23] qcow2: Add subcluster support to expand_zero_clusters_in_l1(), Alberto Garcia, 2019/10/15
- [RFC PATCH 21/23] qcow2: Add subcluster support to handle_alloc_space(), Alberto Garcia, 2019/10/15
- [RFC PATCH 22/23] qcow2: Restrict qcow2_co_pwrite_zeroes() to full clusters only, Alberto Garcia, 2019/10/15
- [RFC PATCH 15/23] qcow2: Add subcluster support to zero_in_l2_slice(), Alberto Garcia, 2019/10/15
- [RFC PATCH 14/23] qcow2: Add subcluster support to qcow2_get_cluster_offset(), Alberto Garcia, 2019/10/15
- [RFC PATCH 17/23] qcow2: Add subcluster support to check_refcounts_l2(), Alberto Garcia, 2019/10/15
- [RFC PATCH 07/23] qcow2: Add subcluster-related fields to BDRVQcow2State, Alberto Garcia, 2019/10/15
- [RFC PATCH 13/23] qcow2: Add subcluster support to calculate_l2_meta(), Alberto Garcia, 2019/10/15
- Re: [RFC PATCH 00/23] Add subcluster allocation to qcow2, Eric Blake, 2019/10/15