qmp: Add QMP query-named-block-nodes to list the named BlockDriverState nodes.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index f043669..5f6308d 100644
--- a/block.c
+++ b/block.c
@@ -32,6 +32,7 @@
 #include "sysemu/sysemu.h"
 #include "qemu/notify.h"
 #include "block/coroutine.h"
+#include "block/qapi.h"
 #include "qmp-commands.h"
 #include "qemu/timer.h"
 
@@ -3291,6 +3292,23 @@
     return NULL;
 }
 
+/* Put this QMP function here so it can access the static graph_bdrv_states. */
+BlockDeviceInfoList *bdrv_named_nodes_list(void)
+{
+    BlockDeviceInfoList *list, *entry;
+    BlockDriverState *bs;
+
+    list = NULL;
+    QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
+        entry = g_malloc0(sizeof(*entry));
+        entry->value = bdrv_block_device_info(bs);
+        entry->next = list;
+        list = entry;
+    }
+
+    return list;
+}
+
 BlockDriverState *bdrv_next(BlockDriverState *bs)
 {
     if (!bs) {