[PATCH 12/21] block: return value from bdrv_replace_node()

[Vladimir Sementsov-Ogievskiy]

Functions with errp argument are not recommened to be void-functions.
Improve bdrv_replace_node().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 include/block/block.h |  4 ++--
 block.c               | 14 ++++++++------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/include/block/block.h b/include/block/block.h
index db37a35cee..ab812e14d8 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -346,8 +346,8 @@ int bdrv_create_file(const char *filename, QemuOpts *opts, 
Error **errp);
 BlockDriverState *bdrv_new(void);
 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
                  Error **errp);
-void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
-                       Error **errp);
+int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
+                      Error **errp);
 
 int bdrv_parse_aio(const char *mode, int *flags);
 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough);
diff --git a/block.c b/block.c
index 1b10b6fb5e..5c94f5a428 100644
--- a/block.c
+++ b/block.c
@@ -4781,14 +4781,14 @@ static bool should_update_child(BdrvChild *c, 
BlockDriverState *to)
  * With auto_skip=false the error is returned if from has a parent which should
  * not be updated.
  */
-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)
 {
+    int ret = -EPERM;
     BdrvChild *c, *next;
     GSList *list = NULL, *p;
     uint64_t perm = 0, shared = BLK_PERM_ALL;
-    int ret;
 
     /* Make sure that @from doesn't go away until we have successfully attached
      * all of its parents to @to. */
@@ -4844,10 +4844,12 @@ out:
     g_slist_free(list);
     bdrv_drained_end(from);
     bdrv_unref(from);
+
+    return ret;
 }
 
-void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
-                       Error **errp)
+int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
+                      Error **errp)
 {
     return bdrv_replace_node_common(from, to, true, errp);
 }
-- 
2.21.3