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-rw-r--r--block/qcow2-cluster.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index a86c5a75a9..4c03639a72 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -414,6 +414,10 @@ static int coroutine_fn do_perform_cow(BlockDriverState *bs,
struct iovec iov;
int ret;
+ if (bytes == 0) {
+ return 0;
+ }
+
iov.iov_len = bytes;
iov.iov_base = qemu_try_blockalign(bs, iov.iov_len);
if (iov.iov_base == NULL) {
@@ -751,31 +755,40 @@ uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
return cluster_offset;
}
-static int perform_cow(BlockDriverState *bs, QCowL2Meta *m, Qcow2COWRegion *r)
+static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
{
BDRVQcow2State *s = bs->opaque;
+ Qcow2COWRegion *start = &m->cow_start;
+ Qcow2COWRegion *end = &m->cow_end;
int ret;
- if (r->nb_bytes == 0) {
+ if (start->nb_bytes == 0 && end->nb_bytes == 0) {
return 0;
}
qemu_co_mutex_unlock(&s->lock);
- ret = do_perform_cow(bs, m->offset, m->alloc_offset, r->offset, r->nb_bytes);
- qemu_co_mutex_lock(&s->lock);
-
+ ret = do_perform_cow(bs, m->offset, m->alloc_offset,
+ start->offset, start->nb_bytes);
if (ret < 0) {
- return ret;
+ goto fail;
}
+ ret = do_perform_cow(bs, m->offset, m->alloc_offset,
+ end->offset, end->nb_bytes);
+
+fail:
+ qemu_co_mutex_lock(&s->lock);
+
/*
* Before we update the L2 table to actually point to the new cluster, we
* need to be sure that the refcounts have been increased and COW was
* handled.
*/
- qcow2_cache_depends_on_flush(s->l2_table_cache);
+ if (ret == 0) {
+ qcow2_cache_depends_on_flush(s->l2_table_cache);
+ }
- return 0;
+ return ret;
}
int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
@@ -795,12 +808,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
}
/* copy content of unmodified sectors */
- ret = perform_cow(bs, m, &m->cow_start);
- if (ret < 0) {
- goto err;
- }
-
- ret = perform_cow(bs, m, &m->cow_end);
+ ret = perform_cow(bs, m);
if (ret < 0) {
goto err;
}