On 23.11.2015 16:59, Kevin Wolf wrote:
> qcow2 accepts a few driver-specific options that overlap semantically
> (e.g. "overlap-check" is an alias of "overlap-check.template", and any
> missing cache size option is derived from the given ones).
> 
> When bdrv_reopen() merges the set of updated options with left out
> options that should be kept at their old value, we need to consider this
> and filter out any duplicates (which would generally cause errors
> because new and old value would contradict each other).
> 
> This patch adds a .bdrv_join_options callback to BlockDriver and
> implements it for qcow2.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/qcow2.c             | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/block/block_int.h |  1 +
>  2 files changed, 48 insertions(+)

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