Re: [Qemu-devel] [PATCH for-2.4 2/5] block: Introduce bdrv_open_child()

[Max Reitz <mreitz@redhat.com>]

On 08.07.2015 21:36, Kevin Wolf wrote:
> It is the same as bdrv_open_image(), except that it doesn't only return
> success or failure, but the newly created BdrvChild object for the new
> child node.
>
> As the BdrvChild object already contains a BlockDriverState pointer (and
> this is supposed to become the only pointer so that bdrv_append() and
> friends can just change a single pointer in BdrvChild), the pbs
> parameter is removed for bdrv_open_child().
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>   block.c               | 71 +++++++++++++++++++++++++++++++++++++--------------
>   include/block/block.h |  6 +++++
>   2 files changed, 58 insertions(+), 19 deletions(-)

Are you planning on removing bdrv_open_image() later on? Because the 
version introduced here behaves differently than the one before this 
patch, in that before the error value returned by bdrv_open() was preserved.

I don't think this is noticeable at all, though, since as long as there 
is an Error object involved, the exact value returned doesn't really 
matter (but I can't verify that assumption, since the value returned by 
bdrv_open_image() seems to be preserved by a lot of nested function calls).

So:

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