Re: [PATCH v5 01/14] block: return status from bdrv_append and friends

[Vladimir Sementsov-Ogievskiy]

12.01.2021 20:27, Alberto Garcia wrote:

On Sat 09 Jan 2021 01:57:58 PM CET, Vladimir Sementsov-Ogievskiy wrote:

-void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
+int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
                           Error **errp)

The indentation of the second line should be adjusted, shouldn't it?

  {
+    int ret;
      bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
          bdrv_inherits_from_recursive(backing_hd, bs);

if (bdrv_is_backing_chain_frozen(bs, child_bs(bs->backing), errp)) {

-        return;
+        return -EPERM;
      }

if (backing_hd) {

@@ -2853,15 +2854,24 @@ void bdrv_set_backing_hd(BlockDriverState *bs, 
BlockDriverState *backing_hd,

      bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds,
                                      bdrv_backing_role(bs), errp);
+    if (!bs->backing) {
+        ret = -EPERM;
+        goto out;
+    }

This is not visible in the patch, but before the bdrv_attach_child()
call there's this:

     if (!backing_hd) {
         goto out;
     }

But in this case 'ret' is still uninitialized.

  out:
      bdrv_refresh_limits(bs, NULL);
+
+    return ret;
  }

-static void bdrv_replace_node_common(BlockDriverState *from,
-                                     BlockDriverState *to,
-                                     bool auto_skip, Error **errp)
+static int bdrv_replace_node_common(BlockDriverState *from,
+                                    BlockDriverState *to,
+                                    bool auto_skip, Error **errp)
  {
      BdrvChild *c, *next;
      GSList *list = NULL, *p;
@@ -4562,6 +4572,7 @@ static void bdrv_replace_node_common(BlockDriverState 
*from,
              goto out;
          }
          if (c->frozen) {
+            ret = -EPERM;
              error_setg(errp, "Cannot change '%s' link to '%s'",
                         c->name, from->node_name);
              goto out;

Same here, you set 'ret' in the second 'goto out' but not in the first.

Oops, you are right, thanks!

--
Best regards,
Vladimir