Re: [Qemu-devel] [PATCH V6 2/5] qemu-img: Add infinite loop checking in bdrv_new_open()

[Jeff Cody <jcody@redhat.com>]

On Tue, Nov 05, 2013 at 10:09:18PM -0500, Xu Wang wrote:
> Every image should be checked if there is infinite loop in backing
> file chain before open it. So infinite loop check was added into
> bdrv_new_open(). If @filename is opened without the flag
> BDRV_O_NO_BACKING, the infinite loop check should be called.
> 
> Signed-off-by: Xu Wang <gesaint@linux.vnet.ibm.com>
> ---
>  qemu-img.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/qemu-img.c b/qemu-img.c
> index d5ec45b..3af7996 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -281,6 +281,14 @@ static BlockDriverState *bdrv_new_open(const char *filename,
>          drv = NULL;
>      }
>  
> +    /* check backing file loop if the whole chain need to be opened */
> +    if (!(flags & BDRV_O_NO_BACKING) &&
> +        !bdrv_backing_chain_okay(filename, fmt)) {
> +        error_report("bdrv_new_open: Open %s failed. There is loop exists "
> +                     "in the backing chain", filename);

I suggest rewording this for grammar; something like:
 +        error_report("bdrv_new_open: Open %s failed. An infinite loop exists "
 +                     "in the backing chain", filename);


> +        goto fail;
> +    }
> +
>      ret = bdrv_open(bs, filename, NULL, flags, drv, &local_err);
>      if (ret < 0) {
>          error_report("Could not open '%s': %s", filename,
> -- 
> 1.8.1.4
> 
>