[Qemu-block] [PATCH 22/22] qcow2-dirty-bitmap: add EXTRA_DATA_COMPATIBLE flag

[Vladimir Sementsov-Ogievskiy]

If this flag is unset and exta data present the bitmap should be
read-only. For now just return error for this case.

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 block/qcow2-dirty-bitmap.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/block/qcow2-dirty-bitmap.c b/block/qcow2-dirty-bitmap.c
index 159e935..95c166c 100644
--- a/block/qcow2-dirty-bitmap.c
+++ b/block/qcow2-dirty-bitmap.c
@@ -45,6 +45,7 @@
 #define BME_RESERVED_FLAGS 0xfffffffc
 #define BME_FLAG_IN_USE 1
 #define BME_FLAG_AUTO   (1U << 1)
+#define BME_FLAG_EXTRA_DATA_COMPATIBLE   (1U << 1)
 
 /* bits [1, 8] U [56, 63] are reserved */
 #define BME_TABLE_ENTRY_RESERVED_MASK 0xff000000000001fe
@@ -333,6 +334,13 @@ static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs, 
QCow2Bitmap *bm,
         return NULL;
     }
 
+    if (!(bmh->flags & BME_FLAG_EXTRA_DATA_COMPATIBLE) &&
+            bmh->extra_data_size != 0) {
+        error_setg(errp, "Uncompatible extra data found for bitmap '%s'",
+                   bm->name);
+        return NULL;
+    }
+
     bitmap_table = g_try_malloc(bmh->bitmap_table_size * sizeof(uint64_t));
     if (bitmap_table == NULL) {
         error_setg_errno(errp, -ENOMEM,
-- 
1.8.3.1