qcow2: Version 3 images

This adds the basic infrastructure to qcow2 to handle version 3 images.
It includes code to create v3 images, allow header updates for v3 images
and checks feature bits.

It still misses support for zero clusters, so this is not a fully
compliant implementation of v3 yet.

The default for creating new images stays at v2 for now.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/block_int.h b/block_int.h
index 0e5a032e77..0acb49f100 100644
--- a/block_int.h
+++ b/block_int.h
@@ -50,6 +50,7 @@
 #define BLOCK_OPT_TABLE_SIZE    "table_size"
 #define BLOCK_OPT_PREALLOC      "preallocation"
 #define BLOCK_OPT_SUBFMT        "subformat"
+#define BLOCK_OPT_COMPAT_LEVEL  "compat"
 
 typedef struct BdrvTrackedRequest BdrvTrackedRequest;