[Qemu-devel] [PATCH 15/21] qcow2: add .bdrv_can_store_dirty_bitmap

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

Realize .bdrv_can_store_dirty_bitmap interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2-bitmap.c | 40 ++++++++++++++++++++++++++++++++++++++++
 block/qcow2.c        |  1 +
 block/qcow2.h        |  4 ++++
 3 files changed, 45 insertions(+)

diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index a975388..55b1112 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -1115,3 +1115,43 @@ fail:
 
     bitmap_list_free(bm_list);
 }
+
+bool qcow2_can_store_dirty_bitmap(BlockDriverState *bs,
+                                  const char *name,
+                                  uint32_t granularity,
+                                  Error **errp)
+{
+    BDRVQcow2State *s = bs->opaque;
+    const char *reason = NULL;
+    bool found;
+    Qcow2BitmapList *bm_list;
+
+    if (check_constraints_on_bitmap(bs, name, granularity) != 0) {
+        reason = "it doesn't satisfy the constraints";
+        goto common_errp;
+    }
+
+    if (s->nb_bitmaps == 0) {
+        return true;
+    }
+
+    bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
+                               s->bitmap_directory_size, errp);
+    if (bm_list == NULL) {
+        return false;
+    }
+
+    found = !!find_bitmap_by_name(bm_list, name);
+    bitmap_list_free(bm_list);
+    if (found) {
+        reason = "bitmap with the same name is already stored";
+        goto common_errp;
+    }
+
+    return true;
+
+common_errp:
+    error_setg(errp, "Can't make bitmap '%s' persistent in '%s', as %s.",
+               name, bdrv_get_device_or_node_name(bs), reason);
+    return false;
+}
diff --git a/block/qcow2.c b/block/qcow2.c
index 66c7f74..cb9c2a2 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3516,6 +3516,7 @@ BlockDriver bdrv_qcow2 = {
 
     .bdrv_load_autoloading_dirty_bitmaps = qcow2_load_autoloading_dirty_bitmaps,
     .bdrv_store_persistent_dirty_bitmaps = qcow2_store_persistent_dirty_bitmaps,
+    .bdrv_can_store_dirty_bitmap = qcow2_can_store_dirty_bitmap,
 };
 
 static void bdrv_qcow2_init(void)
diff --git a/block/qcow2.h b/block/qcow2.h
index d9a7643..e7a44a1 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -616,5 +616,9 @@ void qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 /* qcow2-bitmap.c functions */
 void qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
+bool qcow2_can_store_dirty_bitmap(BlockDriverState *bs,
+                                  const char *name,
+                                  uint32_t granularity,
+                                  Error **errp);
 
 #endif
-- 
1.8.3.1