block: add snapshot info query function bdrv_query_snapshot_info_list()

This patch adds function bdrv_query_snapshot_info_list(), which will
retrieve snapshot info of an image in qmp object format. The implementation
is based on the code moved from qemu-img.c with modification to fit more
for qmp based block layer API.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/qemu-img.c b/qemu-img.c
index e089c78..e3d8fe3 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1667,7 +1667,10 @@ static ImageInfoList *collect_image_info_list(const char *filename,
 
         info = g_new0(ImageInfo, 1);
         bdrv_collect_image_info(bs, info, filename);
-        bdrv_collect_snapshots(bs, info);
+        bdrv_query_snapshot_info_list(bs, &info->snapshots, NULL);
+        if (info->snapshots) {
+            info->has_snapshots = true;
+        }
 
         elem = g_new0(ImageInfoList, 1);
         elem->value = info;