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[PATCH v5 3/6] qcow2: introduce is_cluster_free() helper
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PATCH v5 3/6] qcow2: introduce is_cluster_free() helper |
Date: |
Fri, 26 Mar 2021 23:00:42 +0300 |
We are going to change the concept of "free host cluster", so let's
clarify it now and add a helper, which we will modify later.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
block/qcow2-refcount.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 543fcf289c..1369724b41 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -962,13 +962,32 @@ int qcow2_update_cluster_refcount(BlockDriverState *bs,
/* cluster allocation functions */
+/*
+ * Cluster is free when its refcount is 0
+ *
+ * Return < 0 if failed to get refcount
+ * 0 if cluster is not free
+ * 1 if cluster is free
+ */
+static int is_cluster_free(BlockDriverState *bs, int64_t cluster_index)
+{
+ int ret;
+ uint64_t refcount;
+
+ ret = qcow2_get_refcount(bs, cluster_index, &refcount);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return refcount == 0;
+}
/* return < 0 if error */
static int64_t alloc_clusters_noref(BlockDriverState *bs, uint64_t size,
uint64_t max)
{
BDRVQcow2State *s = bs->opaque;
- uint64_t i, nb_clusters, refcount;
+ uint64_t i, nb_clusters;
int ret;
/* We can't allocate clusters if they may still be queued for discard. */
@@ -980,11 +999,11 @@ static int64_t alloc_clusters_noref(BlockDriverState *bs,
uint64_t size,
retry:
for(i = 0; i < nb_clusters; i++) {
uint64_t next_cluster_index = s->free_cluster_index++;
- ret = qcow2_get_refcount(bs, next_cluster_index, &refcount);
+ ret = is_cluster_free(bs, next_cluster_index);
if (ret < 0) {
return ret;
- } else if (refcount != 0) {
+ } else if (!ret) {
goto retry;
}
}
@@ -1031,7 +1050,7 @@ int64_t qcow2_alloc_clusters_at(BlockDriverState *bs,
uint64_t offset,
int64_t nb_clusters)
{
BDRVQcow2State *s = bs->opaque;
- uint64_t cluster_index, refcount;
+ uint64_t cluster_index;
uint64_t i;
int ret;
@@ -1044,10 +1063,10 @@ int64_t qcow2_alloc_clusters_at(BlockDriverState *bs,
uint64_t offset,
/* Check how many clusters there are free */
cluster_index = offset >> s->cluster_bits;
for(i = 0; i < nb_clusters; i++) {
- ret = qcow2_get_refcount(bs, cluster_index++, &refcount);
+ ret = is_cluster_free(bs, cluster_index++);
if (ret < 0) {
return ret;
- } else if (refcount != 0) {
+ } else if (!ret) {
break;
}
}
--
2.29.2
- [PATCH v5 0/6] qcow2: fix parallel rewrite and discard (lockless), Vladimir Sementsov-Ogievskiy, 2021/03/26
- [PATCH v5 1/6] iotests: add qcow2-discard-during-rewrite, Vladimir Sementsov-Ogievskiy, 2021/03/26
- [PATCH v5 3/6] qcow2: introduce is_cluster_free() helper,
Vladimir Sementsov-Ogievskiy <=
- [PATCH v5 2/6] qcow2: fix cache discarding in update_refcount(), Vladimir Sementsov-Ogievskiy, 2021/03/26
- [PATCH v5 4/6] qcow2: introduce inflight-write-counters, Vladimir Sementsov-Ogievskiy, 2021/03/26
- [PATCH v5 5/6] qcow2: consider in-flight-writes when freeing clusters, Vladimir Sementsov-Ogievskiy, 2021/03/26
- [PATCH v5 6/6] qcow2: do not discard host clusters during in-flight writes, Vladimir Sementsov-Ogievskiy, 2021/03/26