In many cases we just want to know whether a BDS has at least one BB
attached, without needing to know the exact BB that is attached. In
contrast to bs->blk, this is still a valid question when more than one
BB can be attached, so just answer it by checking the parents list.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Max Reitz <mre...@redhat.com>
---
block/block-backend.c | 17 +++++++++++++++++
include/sysemu/block-backend.h | 1 +
2 files changed, 18 insertions(+)
diff --git a/block/block-backend.c b/block/block-backend.c
index 8d6fc77..9dcac97 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -395,6 +395,23 @@ BlockDriverState *blk_bs(BlockBackend *blk)
}
/*
+ * Returns true if @bs has an associated BlockBackend.
+ */
+bool bdrv_has_blk(BlockDriverState *bs)
+{
+ BdrvChild *child;
+ QLIST_FOREACH(child, &bs->parents, next_parent) {
+ if (child->role == &child_root) {
+ assert(bs->blk);
+ return true;
+ }
+ }
+
+ assert(!bs->blk);
+ return false;
+}
+
+/*
* Return @blk's DriveInfo if any, else null.
*/
DriveInfo *blk_legacy_dinfo(BlockBackend *blk)
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 79f39b8..44a222d 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -99,6 +99,7 @@ BlockBackend *blk_by_public(BlockBackendPublic *public);
BlockDriverState *blk_bs(BlockBackend *blk);
void blk_remove_bs(BlockBackend *blk);
void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs);
+bool bdrv_has_blk(BlockDriverState *bs);
void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow);
void blk_iostatus_enable(BlockBackend *blk);
--
1.8.3.1
