diff options
| -rw-r--r-- | block/commit.c | 1 | ||||
| -rw-r--r-- | block/mirror.c | 1 | ||||
| -rw-r--r-- | include/block/block_int-common.h | 13 |
3 files changed, 15 insertions, 0 deletions
diff --git a/block/commit.c b/block/commit.c index 38571510cb..e210e86bac 100644 --- a/block/commit.c +++ b/block/commit.c @@ -238,6 +238,7 @@ static BlockDriver bdrv_commit_top = { .bdrv_child_perm = bdrv_commit_top_child_perm, .is_filter = true, + .filtered_child_is_backing = true, }; void commit_start(const char *job_id, BlockDriverState *bs, diff --git a/block/mirror.c b/block/mirror.c index 80c0109d39..f9432af3df 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -1587,6 +1587,7 @@ static BlockDriver bdrv_mirror_top = { .bdrv_child_perm = bdrv_mirror_top_child_perm, .is_filter = true, + .filtered_child_is_backing = true, }; static BlockJob *mirror_start_job( diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index d7c0a7e96f..95392052c9 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -120,6 +120,19 @@ struct BlockDriver { */ bool is_filter; /* + * Only make sense for filter drivers, for others must be false. + * If true, filtered child is bs->backing. Otherwise it's bs->file. + * Only two internal filters use bs->backing as filtered child and has this + * field set to true: mirror_top and commit_top. + * + * Never create any more such filters! + * + * TODO: imagine how to deprecate this behavior and make all filters work + * similarly using bs->file as filtered child. + */ + bool filtered_child_is_backing; + + /* * Set to true if the BlockDriver is a format driver. Format nodes * generally do not expect their children to be other format nodes * (except for backing files), and so format probing is disabled |