block: mark bdrv_drained_begin() and friends as GRAPH_UNLOCKED

All of bdrv_drain_all_begin(), bdrv_drain_all() and
bdrv_drained_begin() poll and are not allowed to be called with the
block graph lock held. Mark the function as such.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Message-ID: <20250530151125.955508-20-f.ebner@proxmox.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

include/block/block-global-state.h

@@ -192,10 +192,10 @@ int bdrv_inactivate_all(void);
 
 int bdrv_flush_all(void);
 void bdrv_close_all(void);
-void bdrv_drain_all_begin(void);
+void GRAPH_UNLOCKED bdrv_drain_all_begin(void);
 void bdrv_drain_all_begin_nopoll(void);
 void bdrv_drain_all_end(void);
-void bdrv_drain_all(void);
+void GRAPH_UNLOCKED bdrv_drain_all(void);
 
 void bdrv_aio_cancel(BlockAIOCB *acb);
 

include/block/block-io.h

@@ -431,7 +431,7 @@ bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent,
  *
  * This function can be recursive.
  */
-void bdrv_drained_begin(BlockDriverState *bs);
+void GRAPH_UNLOCKED bdrv_drained_begin(BlockDriverState *bs);
 
 /**
  * bdrv_do_drained_begin_quiesce: