[Qemu-devel] [PATCH 1/6] fix format name for backing file

[Paolo Bonzini <pbonzini@redhat.com>]

The new image's backing file is the existing image, so we need to take
the format from there.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockdev.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index d78aa51..96a893b 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -800,7 +800,8 @@ void qmp_blockdev_group_snapshot_sync(SnapshotDevList *dev_list,
         /* create new image w/backing file */
         ret = bdrv_img_create(snapshot_file, format,
                               states->old_bs->filename,
-                              drv->format_name, NULL, -1, flags);
+                              states->old_bs->drv->format_name,
+                              NULL, -1, flags);
         if (ret) {
             error_set(errp, QERR_OPEN_FILE_FAILED, snapshot_file);
             goto delete_and_fail;
-- 
1.7.7.6