[PULL,04/51] block: refactor bdrv_list_refresh_perms to allow any list of nodes

diff --git a/block.c b/block.c
index f2f9178832..385ed3cd53 100644
--- a/block.c
+++ b/block.c
@@ -2521,8 +2521,12 @@  static int bdrv_node_refresh_perm(BlockDriverState *bs, BlockReopenQueue *q,
     return 0;
 }
 
-static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q,
-                                   Transaction *tran, Error **errp)
+/*
+ * @list is a product of bdrv_topological_dfs() (may be called several times) -
+ * a topologically sorted subgraph.
+ */
+static int bdrv_do_refresh_perms(GSList *list, BlockReopenQueue *q,
+                                 Transaction *tran, Error **errp)
 {
     int ret;
     BlockDriverState *bs;
@@ -2544,6 +2548,24 @@  static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q,
     return 0;
 }
 
+/*
+ * @list is any list of nodes. List is completed by all subtrees and
+ * topologically sorted. It's not a problem if some node occurs in the @list
+ * several times.
+ */
+static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q,
+                                   Transaction *tran, Error **errp)
+{
+    g_autoptr(GHashTable) found = g_hash_table_new(NULL, NULL);
+    g_autoptr(GSList) refresh_list = NULL;
+
+    for ( ; list; list = list->next) {
+        refresh_list = bdrv_topological_dfs(refresh_list, found, list->data);
+    }
+
+    return bdrv_do_refresh_perms(refresh_list, q, tran, errp);
+}
+
 void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
                               uint64_t *shared_perm)
 {
@@ -2604,7 +2626,7 @@  static int bdrv_refresh_perms(BlockDriverState *bs, Transaction *tran,
         tran = local_tran = tran_new();
     }
 
-    ret = bdrv_list_refresh_perms(list, NULL, tran, errp);
+    ret = bdrv_do_refresh_perms(list, NULL, tran, errp);
 
     if (local_tran) {
         tran_finalize(local_tran, ret);
@@ -4360,7 +4382,6 @@  int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
     BlockReopenQueueEntry *bs_entry, *next;
     AioContext *ctx;
     Transaction *tran = tran_new();
-    g_autoptr(GHashTable) found = NULL;
     g_autoptr(GSList) refresh_list = NULL;
 
     assert(qemu_get_current_aio_context() == qemu_get_aio_context());
@@ -4390,18 +4411,15 @@  int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
         bs_entry->prepared = true;
     }
 
-    found = g_hash_table_new(NULL, NULL);
     QTAILQ_FOREACH(bs_entry, bs_queue, entry) {
         BDRVReopenState *state = &bs_entry->state;
 
-        refresh_list = bdrv_topological_dfs(refresh_list, found, state->bs);
+        refresh_list = g_slist_prepend(refresh_list, state->bs);
         if (state->old_backing_bs) {
-            refresh_list = bdrv_topological_dfs(refresh_list, found,
-                                                state->old_backing_bs);
+            refresh_list = g_slist_prepend(refresh_list, state->old_backing_bs);
         }
         if (state->old_file_bs) {
-            refresh_list = bdrv_topological_dfs(refresh_list, found,
-                                                state->old_file_bs);
+            refresh_list = g_slist_prepend(refresh_list, state->old_file_bs);
         }
     }
 
@@ -5118,7 +5136,6 @@  static int bdrv_replace_node_common(BlockDriverState *from,
                                     Error **errp)
 {
     Transaction *tran = tran_new();
-    g_autoptr(GHashTable) found = NULL;
     g_autoptr(GSList) refresh_list = NULL;
     BlockDriverState *to_cow_parent = NULL;
     int ret;
@@ -5159,10 +5176,8 @@  static int bdrv_replace_node_common(BlockDriverState *from,
         bdrv_remove_child(bdrv_filter_or_cow_child(to_cow_parent), tran);
     }
 
-    found = g_hash_table_new(NULL, NULL);
-
-    refresh_list = bdrv_topological_dfs(refresh_list, found, to);
-    refresh_list = bdrv_topological_dfs(refresh_list, found, from);
+    refresh_list = g_slist_prepend(refresh_list, to);
+    refresh_list = g_slist_prepend(refresh_list, from);
 
     ret = bdrv_list_refresh_perms(refresh_list, NULL, tran, errp);
     if (ret < 0) {
@@ -5247,7 +5262,6 @@  int bdrv_replace_child_bs(BdrvChild *child, BlockDriverState *new_bs,
 {
     int ret;
     Transaction *tran = tran_new();
-    g_autoptr(GHashTable) found = NULL;
     g_autoptr(GSList) refresh_list = NULL;
     BlockDriverState *old_bs = child->bs;
 
@@ -5259,9 +5273,8 @@  int bdrv_replace_child_bs(BdrvChild *child, BlockDriverState *new_bs,
 
     bdrv_replace_child_tran(child, new_bs, tran);
 
-    found = g_hash_table_new(NULL, NULL);
-    refresh_list = bdrv_topological_dfs(refresh_list, found, old_bs);
-    refresh_list = bdrv_topological_dfs(refresh_list, found, new_bs);
+    refresh_list = g_slist_prepend(refresh_list, old_bs);
+    refresh_list = g_slist_prepend(refresh_list, new_bs);
 
     ret = bdrv_list_refresh_perms(refresh_list, NULL, tran, errp);