qcow2: Save disk size in snapshot header

This allows that different snapshots of an image can have different
sizes, which is a requirement for enabling image resizing even with
images that have internal snapshots.

We don't do the actual support for it now, but make sure that the
additional field is present and not completely ignored in all version 3
images. When trying to load a snapshot of different size, it returns
an error.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/block/qcow2.h b/block/qcow2.h
index e4ac366cfc..ddb976a759 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -78,6 +78,7 @@ typedef struct QCowSnapshot {
     uint32_t l1_size;
     char *id_str;
     char *name;
+    uint64_t disk_size;
     uint64_t vm_state_size;
     uint32_t date_sec;
     uint32_t date_nsec;