[PATCH v2 17/36] block: add bdrv_list_* permission update functions

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

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>
---
 block.c | 106 +++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 71 insertions(+), 35 deletions(-)

diff --git a/block.c b/block.c
index 4a43a33401..6996aee1cf 100644
--- a/block.c
+++ b/block.c
@@ -2176,7 +2176,8 @@ 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,
+                                GSList **tran, Error **errp)
 {
     BlockDriver *drv = bs->drv;
     BdrvChild *c;
@@ -2224,7 +2225,7 @@ 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;
@@ -2243,36 +2244,53 @@ 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;
 }
 
-static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
-                           uint64_t cumulative_perms,
-                           uint64_t cumulative_shared_perms,
-                           GSList *ignore_children, Error **errp)
+/*
+ * 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,
+                                  GSList **tran, Error **errp)
 {
     int ret;
-    BlockDriverState *root = bs;
-    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, root);
+    BlockDriverState *bs;
 
-    for ( ; list; list = list->next) {
+    if (use_cumulative_perms) {
         bs = list->data;
 
-        if (bs != root) {
-            if (!bdrv_check_parents_compliance(bs, ignore_children, errp)) {
-                return -EINVAL;
-            }
+        ret = bdrv_node_check_perm(bs, q, cumulative_perms,
+                                   cumulative_shared_perms,
+                                   ignore_children, tran, errp);
+        if (ret < 0) {
+            return ret;
+        }
 
-            bdrv_get_cumulative_perm(bs, &cumulative_perms,
-                                     &cumulative_shared_perms);
+        list = list->next;
+    }
+
+    for ( ; list; list = list->next) {
+        bs = list->data;
+
+        if (!bdrv_check_parents_compliance(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);
+                                   ignore_children, tran, errp);
         if (ret < 0) {
             return ret;
         }
@@ -2281,6 +2299,23 @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
     return 0;
 }
 
+static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
+                           uint64_t cumulative_perms,
+                           uint64_t cumulative_shared_perms,
+                           GSList *ignore_children, Error **errp)
+{
+    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs);
+    return bdrv_check_perm_common(list, q, true, cumulative_perms,
+                                  cumulative_shared_perms, ignore_children,
+                                  NULL, errp);
+}
+
+static int bdrv_list_refresh_perms(GSList *list, BlockReopenQueue *q,
+                                   GSList **tran, Error **errp)
+{
+    return bdrv_check_perm_common(list, q, false, 0, 0, NULL, tran, errp);
+}
+
 /*
  * Notifies drivers that after a previous bdrv_check_perm() call, the
  * permission update is not performed and any preparations made for it (e.g.
@@ -2302,15 +2337,19 @@ 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;
@@ -2334,15 +2373,19 @@ 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)
 {
@@ -2450,20 +2493,13 @@ 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;
+    GSList *tran = NULL;
+    g_autoptr(GSList) list = bdrv_topological_dfs(NULL, NULL, bs);
 
-    if (!bdrv_check_parents_compliance(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);
+    ret = bdrv_list_refresh_perms(list, NULL, &tran, errp);
+    tran_finalize(tran, ret);
 
-    return 0;
+    return ret;
 }
 
 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
-- 
2.21.3