Re: [Qemu-devel] [PATCH V2 1/2] qcow2: free allocated cluster on fail in qcow2_write_snapshots()

[Stefan Hajnoczi]

On Fri, May 17, 2013 at 03:56:44PM +0800, Wenchao Xia wrote:
> Signed-off-by: Wenchao Xia <address@hidden>
> ---
>  block/qcow2-snapshot.c |   10 ++++++----
>  1 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
> index 992a5c8..45da32d 100644
> --- a/block/qcow2-snapshot.c
> +++ b/block/qcow2-snapshot.c
> @@ -180,13 +180,13 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
>  
>      /* Allocate space for the new snapshot list */
>      snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size);
> -    offset = snapshots_offset;
> -    if (offset < 0) {
> -        return offset;
> +    ret = offset = snapshots_offset;
> +    if (ret < 0) {
> +        goto fail;
>      }

If qcow2_alloc_clusters() failed then we must not call
qcow2_free_clusters().