[Qemu-block] [PATCH 21/29] qcow2-bitmap: add EXTRA_DATA_COMPATIBLE flag

[Vladimir Sementsov-Ogievskiy]

If this flag is unset and extra data is 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-bitmap.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index 1c46dcb..a00eae4 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -47,6 +47,7 @@
 #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
@@ -600,6 +601,13 @@ static BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs,
         goto fail;
     }
 
+    if (!(bmh->flags & BME_FLAG_EXTRA_DATA_COMPATIBLE) &&
+            bmh->extra_data_size != 0) {
+        error_setg(errp, "Incompatible extra data found for bitmap '%s'",
+                   name);
+        goto fail;
+    }
+
     ret = bitmap_table_load(bs, bmh, &bitmap_table);
     if (ret < 0) {
         error_setg_errno(errp, -ret,
-- 
1.8.3.1