Re: [Qemu-devel] [PATCH v6 19/25] block: Add BlockDriver.bdrv_gather_child_options

[Kevin Wolf <kwolf@redhat.com>]

Am 29.09.2017 um 18:53 hat Max Reitz geschrieben:
> Some follow-up patches will rework the way bs->full_open_options is
> refreshed in bdrv_refresh_filename(). The new implementation will remove
> the need for the block drivers' bdrv_refresh_filename() implementations
> to set bs->full_open_options; instead, it will be generic and use static
> information from each block driver.
> 
> However, by implementing bdrv_gather_child_options(), block drivers will
> still be able to override the way the full_open_options of their
> children are incorporated into their own.
> 
> We need to implement this function for VMDK because we have to prevent
> the generic implementation from gathering the options of all children:
> It is not possible to specify options for the extents through the
> runtime options.

Sounds more like a bug than a feature.

> For quorum, the child names that would be used by the generic
> implementation and the ones that we actually want to use differ. See
> quorum_gather_child_options() for more information.

:-/

What was the conclusion of our discussion at KVM Forum again? I just
remember that this caused problems in other contexts like dynamic
reconfiguration, too.

> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  include/block/block_int.h | 13 +++++++++++++
>  block/quorum.c            | 30 ++++++++++++++++++++++++++++++
>  block/vmdk.c              | 13 +++++++++++++
>  3 files changed, 56 insertions(+)

Kevin