[PATCH 3/4] block: implement 'resize' callback for child_of_bds class

[Fiona Ebner]

If a node below a filter node is resized, the size of the filter node
is now also refreshed (recursively for filter parents).

Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
---
 block.c                          | 12 ++++++++++++
 include/block/block_int-common.h |  2 +-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/block.c b/block.c
index bfd4340b24..449f814ebe 100644
--- a/block.c
+++ b/block.c
@@ -1497,6 +1497,17 @@ static void GRAPH_WRLOCK bdrv_child_cb_detach(BdrvChild 
*child)
     }
 }
 
+static void coroutine_fn GRAPH_RDLOCK bdrv_child_cb_resize(BdrvChild *child)
+{
+    BlockDriverState *bs = child->opaque;
+
+    if (bs->drv && bs->drv->is_filter) {
+        /* Best effort, ignore errors. */
+        bdrv_co_refresh_total_sectors(bs, bs->total_sectors);
+        bdrv_co_parent_cb_resize(bs);
+    }
+}
+
 static int bdrv_child_cb_update_filename(BdrvChild *c, BlockDriverState *base,
                                          const char *filename,
                                          bool backing_mask_protocol,
@@ -1529,6 +1540,7 @@ const BdrvChildClass child_of_bds = {
     .detach          = bdrv_child_cb_detach,
     .inactivate      = bdrv_child_cb_inactivate,
     .change_aio_ctx  = bdrv_child_cb_change_aio_ctx,
+    .resize          = bdrv_child_cb_resize,
     .update_filename = bdrv_child_cb_update_filename,
     .get_parent_aio_context = child_of_bds_get_parent_aio_context,
 };
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 692a9696d1..6670db2f85 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -1023,7 +1023,7 @@ struct BdrvChildClass {
     /*
      * Notifies the parent that the child was resized.
      */
-    void (*resize)(BdrvChild *child);
+    void GRAPH_RDLOCK_PTR (*resize)(BdrvChild *child);
 
     /*
      * Returns a name that is supposedly more useful for human users than the
-- 
2.47.2