Re: [PATCH 02/21] block: introduce blk_replace_bs

[Max Reitz]

On 17.05.21 08:44, Vladimir Sementsov-Ogievskiy wrote:
Add function to change bs inside blk.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
  include/sysemu/block-backend.h | 1 +
  block/block-backend.c          | 8 ++++++++
  2 files changed, 9 insertions(+)

diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 880e903293..aec05ef0a0 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -98,6 +98,7 @@ BlockBackend *blk_by_public(BlockBackendPublic *public);
  BlockDriverState *blk_bs(BlockBackend *blk);
  void blk_remove_bs(BlockBackend *blk);
  int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp);
+int blk_replace_bs(BlockBackend *blk, BlockDriverState *new_bs, Error **errp);
  bool bdrv_has_blk(BlockDriverState *bs);
  bool bdrv_is_root_node(BlockDriverState *bs);
  int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
diff --git a/block/block-backend.c b/block/block-backend.c
index de5496af66..b1abc6f3e6 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -870,6 +870,14 @@ int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, 
Error **errp)
      return 0;
  }
  
+/*
+ * Change BlockDriverState associated with @blk.
+ */
+int blk_replace_bs(BlockBackend *blk, BlockDriverState *new_bs, Error **errp)
+{
+    return bdrv_replace_child_bs(blk->root, new_bs, errp);
+}

Reviewed-by: Max Reitz <mre...@redhat.com>

(Looks indeed like we don’t need to do any of the things that 
blk_insert_bs() and blk_remove_bs() do besides inserting and removing 
the node.)