Re: [Qemu-devel] [PATCH V2 3/4] blockdev: Allow snapshoting of protocols.

[Kevin Wolf]

Am 28.01.2013 18:04, schrieb Benoît Canet:
> Signed-off-by: Benoit Canet <address@hidden>
> ---
>  blockdev.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 0ce45c5..b1f388b 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -800,7 +800,8 @@ void qmp_transaction(BlockdevActionList *dev_list, Error 
> **errp)
>          /* We will manually add the backing_hd field to the bs later */
>          states->new_bs = bdrv_new("");
>          ret = bdrv_open(states->new_bs, new_image_file,
> -                        flags | BDRV_O_NO_BACKING, drv);
> +                        flags | BDRV_O_NO_BACKING,
> +                        path_has_protocol(new_image_file) ?  NULL : drv);
>          if (ret != 0) {
>              error_set(errp, QERR_OPEN_FILE_FAILED, new_image_file);
>              goto delete_and_fail;

Wait, what's happening here? I don't understand this patch and how it's
related to snapshotting non-file protocols (if this is even what you
mean). What is your exact scenario, what does the existing code do in
it, and how does this change improve it? An empty commit message is
definitely not appropriate for such a change.

In any case, using NULL as drv for bdrv_open() looks plain wrong.

Kevin