block: Add bdrv_get_node_name

This returns the node name of a BDS. Remove the TODO comment and expect
the callers to be explicit.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

diff --git a/block.c b/block.c
index e8a0342..866c8b4 100644
--- a/block.c
+++ b/block.c
@@ -3817,6 +3817,11 @@
     return QTAILQ_NEXT(bs, device_list);
 }
 
+const char *bdrv_get_node_name(const BlockDriverState *bs)
+{
+    return bs->node_name;
+}
+
 /* TODO check what callers really want: bs->node_name or blk_name() */
 const char *bdrv_get_device_name(const BlockDriverState *bs)
 {

include/block/block.h

diff --git a/include/block/block.h b/include/block/block.h
index c3a68d8..610be9f 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -382,6 +382,7 @@
 int bdrv_query_missing_keys(void);
 void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
                          void *opaque);
+const char *bdrv_get_node_name(const BlockDriverState *bs);
 const char *bdrv_get_device_name(const BlockDriverState *bs);
 int bdrv_get_flags(BlockDriverState *bs);
 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,