[Qemu-devel] [PATCH 14/17] qapi: add md5 checksum of last dirty bitmap level to query-block

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/dirty-bitmap.c   | 1 +
 include/qemu/hbitmap.h | 8 ++++++++
 qapi/block-core.json   | 5 ++++-
 util/hbitmap.c         | 8 ++++++++
 4 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 7d4cade..c0e7e51 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -332,6 +332,7 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
         info->has_name = !!bm->name;
         info->name = g_strdup(bm->name);
         info->status = bdrv_dirty_bitmap_status(bm);
+        info->md5 = hbitmap_md5(bm->bitmap);
         entry->value = info;
         *plist = entry;
         plist = &entry->next;
diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index 00dbb60..6a57902 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -227,6 +227,14 @@ void hbitmap_deserialize_zeroes(HBitmap *hb, uint64_t start, uint64_t count,
 void hbitmap_deserialize_finish(HBitmap *hb);
 
 /**
+ * hbitmap_md5:
+ * @bitmap: HBitmap to operate on.
+ *
+ * Returns md5 checksum of the last level.
+ */
+char *hbitmap_md5(const HBitmap *bitmap);
+
+/**
  * hbitmap_free:
  * @hb: HBitmap to operate on.
  *
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 0a915ed..9745687 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -360,11 +360,14 @@
 #
 # @status: current status of the dirty bitmap (since 2.4)
 #
+# @md5: md5 checksum (as a hexadecimal string) of the last bitmap level
+#       (since 2.6)
+#
 # Since: 1.3
 ##
 { 'struct': 'BlockDirtyInfo',
   'data': {'*name': 'str', 'count': 'int', 'granularity': 'uint32',
-           'status': 'DirtyBitmapStatus'} }
+           'status': 'DirtyBitmapStatus', 'md5': 'str'} }
 
 ##
 # @BlockInfo:
diff --git a/util/hbitmap.c b/util/hbitmap.c
index 1e49ab7..caf4af6 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -664,3 +664,11 @@ void hbitmap_free_meta(HBitmap *hb)
     hbitmap_free(hb->meta);
     hb->meta = NULL;
 }
+
+char *hbitmap_md5(const HBitmap *bitmap)
+{
+    uint64_t size =
+        MAX((bitmap->size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1);
+    const guchar *data = (const guchar *)bitmap->levels[HBITMAP_LEVELS - 1];
+    return g_compute_checksum_for_data(G_CHECKSUM_MD5, data, size);
+}
-- 
1.8.3.1