qcow2: Add support for ImageInfoSpecific

Add a new ImageInfoSpecificQCow2 type as a subtype of ImageInfoSpecific.
This contains the compatibility level as a string and an optional
lazy_refcounts boolean (optional means mandatory for compat >= 1.1 and
not available for compat == 0.10).

Also, add qcow2_get_specific_info, which returns this information.

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

block/qcow2.c

@@ -1810,6 +1810,33 @@ static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     return 0;
 }
 
+static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs)
+{
+    BDRVQcowState *s = bs->opaque;
+    ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1);
+
+    *spec_info = (ImageInfoSpecific){
+        .kind  = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
+        {
+            .qcow2 = g_new(ImageInfoSpecificQCow2, 1),
+        },
+    };
+    if (s->qcow_version == 2) {
+        *spec_info->qcow2 = (ImageInfoSpecificQCow2){
+            .compat = g_strdup("0.10"),
+        };
+    } else if (s->qcow_version == 3) {
+        *spec_info->qcow2 = (ImageInfoSpecificQCow2){
+            .compat             = g_strdup("1.1"),
+            .lazy_refcounts     = s->compatible_features &
+                                  QCOW2_COMPAT_LAZY_REFCOUNTS,
+            .has_lazy_refcounts = true,
+        };
+    }
+
+    return spec_info;
+}
+
 #if 0
 static void dump_refcounts(BlockDriverState *bs)
 {
@@ -2130,6 +2157,7 @@ static BlockDriver bdrv_qcow2 = {
     .bdrv_snapshot_list     = qcow2_snapshot_list,
     .bdrv_snapshot_load_tmp     = qcow2_snapshot_load_tmp,
     .bdrv_get_info      = qcow2_get_info,
+    .bdrv_get_specific_info = qcow2_get_specific_info,
 
     .bdrv_save_vmstate    = qcow2_save_vmstate,
     .bdrv_load_vmstate    = qcow2_load_vmstate,

qapi-schema.json

@@ -209,6 +209,21 @@
             'date-sec': 'int', 'date-nsec': 'int',
             'vm-clock-sec': 'int', 'vm-clock-nsec': 'int' } }
 
+##
+# @ImageInfoSpecificQCow2:
+#
+# @compat: compatibility level
+#
+# @lazy-refcounts: #optional on or off; only valid for compat >= 1.1
+#
+# Since: 1.7
+##
+{ 'type': 'ImageInfoSpecificQCow2',
+  'data': {
+      'compat': 'str',
+      '*lazy-refcounts': 'bool'
+  } }
+
 ##
 # @ImageInfoSpecific:
 #
@@ -219,6 +234,7 @@
 
 { 'union': 'ImageInfoSpecific',
   'data': {
+      'qcow2': 'ImageInfoSpecificQCow2'
   } }
 
 ##