Re: [Qemu-devel] [Qemu-block] [PATCH for-2.10 1/5] block: Fix order in bdrv_replace_child()

[Jeff Cody <jcody@redhat.com>]

On Thu, Aug 03, 2017 at 05:02:57PM +0200, Kevin Wolf wrote:
> Commit 8ee03995 refactored the code incorrectly and broke the release of
> permissions on the old BDS. Instead of changing the permissions to the
> new required values after removing the old BDS from the list of
> children, it only re-obtains the permissions it already had.
> 
> Change the order of operations so that the old BDS is removed again
> before calculating the new required permissions.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/block.c b/block.c
> index ce9cce7b3c..ab908cdc50 100644
> --- a/block.c
> +++ b/block.c
> @@ -1933,6 +1933,8 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
>      BlockDriverState *old_bs = child->bs;
>      uint64_t perm, shared_perm;
>  
> +    bdrv_replace_child_noperm(child, new_bs);
> +
>      if (old_bs) {
>          /* Update permissions for old node. This is guaranteed to succeed
>           * because we're just taking a parent away, so we're loosening
> @@ -1942,8 +1944,6 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
>          bdrv_set_perm(old_bs, perm, shared_perm);
>      }
>  
> -    bdrv_replace_child_noperm(child, new_bs);
> -
>      if (new_bs) {
>          bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm);
>          bdrv_set_perm(new_bs, perm, shared_perm);
> -- 
> 2.13.3
> 
> 

Reviewed-by: Jeff Cody <jcody@redhat.com>