block: add bdrv_list_* permission update functions

Add new interface, allowing use of existing node list. It will be used
to fix bdrv_replace_node() in the further commit.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210428151804.439460-16-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

@@ -2249,7 +2249,8 @@ static int bdrv_drv_set_perm(BlockDriverState *bs, uint64_t perm,
 static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
                                 uint64_t cumulative_perms,
                                 uint64_t cumulative_shared_perms,
-                                GSList *ignore_children, Error **errp)
+                                GSList *ignore_children,
+                                Transaction *tran, Error **errp)
 {
     BlockDriver *drv = bs->drv;
     BdrvChild *c;
@@ -2297,7 +2298,7 @@ static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
         return 0;
     }
 
-    ret = bdrv_drv_set_perm(bs, cumulative_perms, cumulative_shared_perms, NULL,
+    ret = bdrv_drv_set_perm(bs, cumulative_perms, cumulative_shared_perms, tran,
                             errp);
     if (ret < 0) {
         return ret;
@@ -2316,7 +2317,56 @@ static int bdrv_node_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
         bdrv_child_perm(bs, c->bs, c, c->role, q,
                         cumulative_perms, cumulative_shared_perms,
                         &cur_perm, &cur_shared);
-        bdrv_child_set_perm_safe(c, cur_perm, cur_shared, NULL);
+        bdrv_child_set_perm_safe(c, cur_perm, cur_shared, tran);
+    }
+
+    return 0;
+}
+
+/*
+ * If use_cumulative_perms is true, use cumulative_perms and
+ * cumulative_shared_perms for first element of the list. Otherwise just refresh
+ * all permissions.
+ */
+static int bdrv_check_perm_common(GSList *list, BlockReopenQueue *q,
+                                  bool use_cumulative_perms,
+                                  uint64_t cumulative_perms,
+                                  uint64_t cumulative_shared_perms,
+                                  GSList *ignore_children,
+                                  Transaction *tran, Error **errp)
+{
+    int ret;
+    BlockDriverState *bs;
+
+    if (use_cumulative_perms) {
+        bs = list->data;
+
+        ret = bdrv_node_check_perm(bs, q, cumulative_perms,
+                                   cumulative_shared_perms,
+                                   ignore_children, tran, errp);
+        if (ret < 0) {
+            return ret;
+        }
+
+        list = list->next;
+    }
+
+    for ( ; list; list = list->next) {
+        bs = list->data;
+
+        if (bdrv_parent_perms_conflict(bs, ignore_children, errp)) {
+            return -EINVAL;
+        }
+
+        bdrv_get_cumulative_perm(bs, &cumulative_perms,
+                                 &cumulative_shared_perms);
+
+        ret = bdrv_node_check_perm(bs, q, cumulative_perms,
+                                   cumulative_shared_perms,
+                                   ignore_children, tran, errp);
+        if (ret < 0) {
+            return ret;
+        }
     }
 
     return 0;
@@ -2327,31 +2377,16 @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
                            uint64_t cumulative_shared_perms,
                            GSList *ignore_children, Error **errp)
 {
-    int ret;
+    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs);
-    BlockDriverState *root = bs;
+    return bdrv_check_perm_common(list, q, true, cumulative_perms,
-    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, root);
+                                  cumulative_shared_perms, ignore_children,
+                                  NULL, errp);
+}
 
-    for ( ; list; list = list->next) {
+static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q,
-        bs = list->data;
+                                   Transaction *tran, Error **errp)
-
+{
-        if (bs != root) {
+    return bdrv_check_perm_common(list, q, false, 0, 0, NULL, tran, errp);
-            if (bdrv_parent_perms_conflict(bs, ignore_children, errp)) {
-                return -EINVAL;
-            }
-
-            bdrv_get_cumulative_perm(bs, &cumulative_perms,
-                                     &cumulative_shared_perms);
-        }
-
-        ret = bdrv_node_check_perm(bs, q, cumulative_perms,
-                                   cumulative_shared_perms,
-                                   ignore_children, errp);
-        if (ret < 0) {
-            return ret;
-        }
-    }
-
-    return 0;
 }
 
 /*
@@ -2375,15 +2410,19 @@ static void bdrv_node_abort_perm_update(BlockDriverState *bs)
     }
 }
 
-static void bdrv_abort_perm_update(BlockDriverState *bs)
+static void bdrv_list_abort_perm_update(GSList *list)
 {
-    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs);
-
     for ( ; list; list = list->next) {
         bdrv_node_abort_perm_update((BlockDriverState *)list->data);
     }
 }
 
+static void bdrv_abort_perm_update(BlockDriverState *bs)
+{
+    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs);
+    return bdrv_list_abort_perm_update(list);
+}
+
 static void bdrv_node_set_perm(BlockDriverState *bs)
 {
     BlockDriver *drv = bs->drv;
@@ -2407,15 +2446,19 @@ static void bdrv_node_set_perm(BlockDriverState *bs)
     }
 }
 
-static void bdrv_set_perm(BlockDriverState *bs)
+static void bdrv_list_set_perm(GSList *list)
 {
-    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs);
-
     for ( ; list; list = list->next) {
         bdrv_node_set_perm((BlockDriverState *)list->data);
     }
 }
 
+static void bdrv_set_perm(BlockDriverState *bs)
+{
+    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs);
+    return bdrv_list_set_perm(list);
+}
+
 void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
                               uint64_t *shared_perm)
 {
@@ -2523,20 +2566,13 @@ static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q,
 static int bdrv_refresh_perms(BlockDriverState *bs, Error **errp)
 {
     int ret;
-    uint64_t perm, shared_perm;
+    Transaction *tran = tran_new();
+    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs);
+
+    ret = bdrv_list_refresh_perms(list, NULL, tran, errp);
+    tran_finalize(tran, ret);
 
-    if (bdrv_parent_perms_conflict(bs, NULL, errp)) {
-        return -EPERM;
-    }
-    bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
-    ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, errp);
-    if (ret < 0) {
-        bdrv_abort_perm_update(bs);
     return ret;
-    }
-    bdrv_set_perm(bs);
-
-    return 0;
 }
 
 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,