diff --git a/block.c b/block.c
index c74e6e7cc1..9283c8d97b 100644
--- a/block.c
+++ b/block.c
@@ -4991,6 +4991,34 @@ static bool should_update_child(BdrvChild *c, BlockDriverState *to)
     return ret;
 }
 
+static int bdrv_replace_node_noperm(BlockDriverState *from,
+                                    BlockDriverState *to,
+                                    bool auto_skip, Transaction *tran,
+                                    Error **errp)
+{
+    BdrvChild *c, *next;
+
+    QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
+        assert(c->bs == from);
+        if (!should_update_child(c, to)) {
+            if (auto_skip) {
+                continue;
+            }
+            error_setg(errp, "Should not change '%s' link to '%s'",
+                       c->name, from->node_name);
+            return -EINVAL;
+        }
+        if (c->frozen) {
+            error_setg(errp, "Cannot change '%s' link to '%s'",
+                       c->name, from->node_name);
+            return -EPERM;
+        }
+        bdrv_replace_child_safe(c, to, tran);
+    }
+
+    return 0;
+}
+
 /*
  * With auto_skip=true bdrv_replace_node_common skips updating from parents
  * if it creates a parent-child relation loop or if parent is block-job.
@@ -5002,7 +5030,6 @@ static int bdrv_replace_node_common(BlockDriverState *from,
                                     BlockDriverState *to,
                                     bool auto_skip, Error **errp)
 {
-    BdrvChild *c, *next;
     Transaction *tran = tran_new();
     g_autoptr(GHashTable) found = NULL;
     g_autoptr(GSList) refresh_list = NULL;
@@ -5022,24 +5049,9 @@ static int bdrv_replace_node_common(BlockDriverState *from,
      * permissions based on new graph. If we fail, we'll roll-back the
      * replacement.
      */
-    QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
-        assert(c->bs == from);
-        if (!should_update_child(c, to)) {
-            if (auto_skip) {
-                continue;
-            }
-            ret = -EINVAL;
-            error_setg(errp, "Should not change '%s' link to '%s'",
-                       c->name, from->node_name);
-            goto out;
-        }
-        if (c->frozen) {
-            ret = -EPERM;
-            error_setg(errp, "Cannot change '%s' link to '%s'",
-                       c->name, from->node_name);
-            goto out;
-        }
-        bdrv_replace_child_safe(c, to, tran);
+    ret = bdrv_replace_node_noperm(from, to, auto_skip, tran, errp);
+    if (ret < 0) {
+        goto out;
     }
 
     found = g_hash_table_new(NULL, NULL);