On 02.08.19 16:03, Kevin Wolf wrote:
> The same change as commit 2b23f28639 ('block/copy-on-read: Fix
> permissions for inactive node') made for the copy-on-read driver can be
> made for bdrv_filter_default_perms(): Retaining the old permissions from
> the BdrvChild if it is given complicates things unnecessary when in the
> end this only means that the options set in the c == NULL case (i.e.
> during child creation) are retained.

My best guess is that we had this code because this way any party could
set or remove the GRAPH_MOD permission and it would be kept through
.bdrv_child_perm() invocations.  (But I think that’s kaputt.)

> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block.c | 12 ++----------
>  1 file changed, 2 insertions(+), 10 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>