Re: [Qemu-devel] [PATCH] vmdk: Switch to heap arrays for vmdk_write_cid

[Peter Xu <peterx@redhat.com>]

On Tue, Mar 08, 2016 at 02:18:35PM +0800, Fam Zheng wrote:
> It is only called once for each opened image, so we can do it the easy
> way.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block/vmdk.c | 25 ++++++++++++++-----------
>  1 file changed, 14 insertions(+), 11 deletions(-)
> 
> diff --git a/block/vmdk.c b/block/vmdk.c
> index a8db5d9..1ec2452 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -274,36 +274,39 @@ static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
>  
>  static int vmdk_write_cid(BlockDriverState *bs, uint32_t cid)

If to use heap in write, do we need to do the same for e.g.,
vmdk_parent_open() and vmdk_read_cid(), to make all things at least
aligned?

>  {
> -    char desc[DESC_SIZE], tmp_desc[DESC_SIZE];
> +    char *desc, *tmp_desc;
>      char *p_name, *tmp_str;
>      BDRVVmdkState *s = bs->opaque;
> -    int ret;
> +    int ret = 0;
>  
> +    desc = g_malloc0(DESC_SIZE);
> +    tmp_desc = g_malloc0(DESC_SIZE);
>      ret = bdrv_pread(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
>      if (ret < 0) {
> -        return ret;
> +        goto out;
>      }
>  
>      desc[DESC_SIZE - 1] = '\0';
>      tmp_str = strstr(desc, "parentCID");
>      if (tmp_str == NULL) {
> -        return -EINVAL;
> +        ret = -EINVAL;
> +        goto out;
>      }
>  
> -    pstrcpy(tmp_desc, sizeof(tmp_desc), tmp_str);
> +    pstrcpy(tmp_desc, DESC_SIZE, tmp_str);
>      p_name = strstr(desc, "CID");
>      if (p_name != NULL) {
>          p_name += sizeof("CID");
> -        snprintf(p_name, sizeof(desc) - (p_name - desc), "%" PRIx32 "\n", cid);
> -        pstrcat(desc, sizeof(desc), tmp_desc);
> +        snprintf(p_name, DESC_SIZE - (p_name - desc), "%" PRIx32 "\n", cid);
> +        pstrcat(desc, DESC_SIZE, tmp_desc);
>      }
>  
>      ret = bdrv_pwrite_sync(bs->file->bs, s->desc_offset, desc, DESC_SIZE);
> -    if (ret < 0) {
> -        return ret;
> -    }
>  
> -    return 0;
> +out:
> +    g_free(desc);
> +    g_free(tmp_desc);
> +    return ret;
>  }
>  
>  static int vmdk_is_cid_valid(BlockDriverState *bs)
> -- 
> 2.4.3
> 
> 

Besides the above nit-pick:

Reviewed-by: Peter Xu <peterx@redhat.com>