Re: [Qemu-devel] [PATCH v2] block: Close backing file early in bdrv_img_create

["Benoît Canet" <benoit.canet@irqsave.net>]

Le Friday 29 Nov 2013 à 21:41:29 (+0100), Max Reitz a écrit :
> Leaving the backing file open although it is not needed anymore can
> cause problems if it is opened through a block driver which allows
> exclusive access only and if the create function of the block driver
> used for the top image (the one being created) tries to close and reopen
> the image file (which will include opening the backing file a second
> time).
> 
> In particular, this will happen with a backing file opened through
> qemu-nbd and using qcow2 as the top image file format (which reopens the
> image to flush it to disk).
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
> v2:
>  - Minimizing the changes prevents introducing a leak of the
>    BlockDriverState in case of an error in bdrv_open() (thanks, Kevin).
> ---
>  block.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/block.c b/block.c
> index 382ea71..6d571ad 100644
> --- a/block.c
> +++ b/block.c
> @@ -4608,6 +4608,9 @@ void bdrv_img_create(const char *filename, const char *fmt,
>  
>              snprintf(buf, sizeof(buf), "%" PRId64, size);
>              set_option_parameter(param, BLOCK_OPT_SIZE, buf);
> +
> +            bdrv_unref(bs);
> +            bs = NULL;
>          } else {
>              error_setg(errp, "Image creation needs a size parameter");
>              goto out;
Reviewed-by: Benoit Canet <benoit@irqsave.net>
> -- 
> 1.8.4.2
> 
>