From abc521a9aa470421dc9285cafe16ff64f3044ac5 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Fri, 1 Feb 2019 20:29:26 +0100 Subject: block: Add BlockDriver.bdrv_gather_child_options 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. For quorum, the child names that would be used by the generic implementation and the ones that we actually (currently) want to use differ. See quorum_gather_child_options() for more information. Note that both of these are cases which are not ideal: In case of VMDK it would probably be nice to be able to specify options for all extents. In case of quorum, the current runtime option structure is simply broken and needs to be fixed (but that is left for another patch). Signed-off-by: Max Reitz Reviewed-by: Alberto Garcia Message-id: 20190201192935.18394-23-mreitz@redhat.com Signed-off-by: Max Reitz --- include/block/block_int.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'include') diff --git a/include/block/block_int.h b/include/block/block_int.h index 160e8cac1f..ab4cf2df07 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -141,6 +141,30 @@ struct BlockDriver { void (*bdrv_refresh_filename)(BlockDriverState *bs, QDict *options); + /* + * Gathers the open options for all children into @target. + * A simple format driver (without backing file support) might + * implement this function like this: + * + * QINCREF(bs->file->bs->full_open_options); + * qdict_put(target, "file", bs->file->bs->full_open_options); + * + * If not specified, the generic implementation will simply put + * all children's options under their respective name. + * + * @backing_overridden is true when bs->backing seems not to be + * the child that would result from opening bs->backing_file. + * Therefore, if it is true, the backing child's options should be + * gathered; otherwise, there is no need since the backing child + * is the one implied by the image header. + * + * Note that ideally this function would not be needed. Every + * block driver which implements it is probably doing something + * shady regarding its runtime option structure. + */ + void (*bdrv_gather_child_options)(BlockDriverState *bs, QDict *target, + bool backing_overridden); + /* * Returns an allocated string which is the directory name of this BDS: It * will be used to make relative filenames absolute by prepending this -- cgit v1.2.3