[PULL,16/22] qcow2: Make qcow2_free_any_clusters() free only one cluster

Commit Message

Max Reitz Sept. 15, 2020, 10:46 a.m. UTC

From: Alberto Garcia <[e-mail]>

This function takes an L2 entry and a number of clusters to free.
Although in principle it can free any type of cluster (using the L2
entry to determine its type) in practice the API is broken because
compressed clusters have a variable size and there is no way to free
more than one without having the L2 entry of each one of them.

The good news all callers are passing nb_clusters=1 so we can simply
get rid of that parameter.

Signed-off-by: Alberto Garcia <[e-mail]>
Message-Id: <[e-mail]>
Reviewed-by: Kevin Wolf <[e-mail]>
Signed-off-by: Max Reitz <[e-mail]>
---
 block/qcow2.h          | 4 ++--
 block/qcow2-cluster.c  | 6 +++---
 block/qcow2-refcount.c | 8 ++++----
 3 files changed, 9 insertions(+), 9 deletions(-)

Patch

diff --git a/block/qcow2.h b/block/qcow2.h
index 83cfa0c391..b73a4cf1f8 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -861,8 +861,8 @@  int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 void qcow2_free_clusters(BlockDriverState *bs,
                           int64_t offset, int64_t size,
                           enum qcow2_discard_type type);
-void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
-                             int nb_clusters, enum qcow2_discard_type type);
+void qcow2_free_any_cluster(BlockDriverState *bs, uint64_t l2_entry,
+                            enum qcow2_discard_type type);
 
 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
     int64_t l1_table_offset, int l1_size, int addend);
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index ce1260e746..1a67b2d928 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1096,7 +1096,7 @@  int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
      */
     if (!m->keep_old_clusters && j != 0) {
         for (i = 0; i < j; i++) {
-            qcow2_free_any_clusters(bs, old_cluster[i], 1, QCOW2_DISCARD_NEVER);
+            qcow2_free_any_cluster(bs, old_cluster[i], QCOW2_DISCARD_NEVER);
         }
     }
 
@@ -1913,7 +1913,7 @@  static int discard_in_l2_slice(BlockDriverState *bs, uint64_t offset,
             set_l2_bitmap(s, l2_slice, l2_index + i, new_l2_bitmap);
         }
         /* Then decrease the refcount */
-        qcow2_free_any_clusters(bs, old_l2_entry, 1, type);
+        qcow2_free_any_cluster(bs, old_l2_entry, type);
     }
 
     qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
@@ -2005,7 +2005,7 @@  static int zero_in_l2_slice(BlockDriverState *bs, uint64_t offset,
 
         qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
         if (unmap) {
-            qcow2_free_any_clusters(bs, old_l2_entry, 1, QCOW2_DISCARD_REQUEST);
+            qcow2_free_any_cluster(bs, old_l2_entry, QCOW2_DISCARD_REQUEST);
         }
         set_l2_entry(s, l2_slice, l2_index + i, new_l2_entry);
         if (has_subclusters(s)) {
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 51e9778ed8..8e649b008e 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1157,8 +1157,8 @@  void qcow2_free_clusters(BlockDriverState *bs,
  * Free a cluster using its L2 entry (handles clusters of all types, e.g.
  * normal cluster, compressed cluster, etc.)
  */
-void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
-                             int nb_clusters, enum qcow2_discard_type type)
+void qcow2_free_any_cluster(BlockDriverState *bs, uint64_t l2_entry,
+                            enum qcow2_discard_type type)
 {
     BDRVQcow2State *s = bs->opaque;
     QCow2ClusterType ctype = qcow2_get_cluster_type(bs, l2_entry);
@@ -1169,7 +1169,7 @@  void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
              ctype == QCOW2_CLUSTER_ZERO_ALLOC))
         {
             bdrv_pdiscard(s->data_file, l2_entry & L2E_OFFSET_MASK,
-                          nb_clusters << s->cluster_bits);
+                          s->cluster_size);
         }
         return;
     }
@@ -1192,7 +1192,7 @@  void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
                                     l2_entry & L2E_OFFSET_MASK);
         } else {
             qcow2_free_clusters(bs, l2_entry & L2E_OFFSET_MASK,
-                                nb_clusters << s->cluster_bits, type);
+                                s->cluster_size, type);
         }
         break;
     case QCOW2_CLUSTER_ZERO_PLAIN: