[Qemu-devel] [PATCH 17/25] qcow2: add .bdrv_can_store_new_dirty_bitmap

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

Realize .bdrv_can_store_new_dirty_bitmap interface.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2-bitmap.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 block/qcow2.c        |  2 ++
 block/qcow2.h        |  4 ++++
 3 files changed, 57 insertions(+)

diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index 4a8dae9961..a07fc0c712 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -1303,3 +1303,54 @@ fail:
 
     bitmap_list_free(bm_list);
 }
+
+bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
+                                      const char *name,
+                                      uint32_t granularity,
+                                      Error **errp)
+{
+    BDRVQcow2State *s = bs->opaque;
+    bool found;
+    Qcow2BitmapList *bm_list;
+
+    if (check_constraints_on_bitmap(bs, name, granularity, errp) != 0) {
+        goto fail;
+    }
+
+    if (s->nb_bitmaps == 0) {
+        return true;
+    }
+
+    if (s->nb_bitmaps >= QCOW2_MAX_BITMAPS) {
+        error_setg(errp,
+                   "Maximum number of persistent bitmaps is already reached");
+        goto fail;
+    }
+
+    if (s->bitmap_directory_size + calc_dir_entry_size(strlen(name), 0) >
+        QCOW2_MAX_BITMAP_DIRECTORY_SIZE)
+    {
+        error_setg(errp, "Not enough space in the bitmap directory");
+        goto fail;
+    }
+
+    bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
+                               s->bitmap_directory_size, errp);
+    if (bm_list == NULL) {
+        goto fail;
+    }
+
+    found = find_bitmap_by_name(bm_list, name);
+    bitmap_list_free(bm_list);
+    if (found) {
+        error_setg(errp, "Bitmap with the same name is already stored");
+        goto fail;
+    }
+
+    return true;
+
+fail:
+    error_prepend(errp, "Can't make bitmap '%s' persistent in '%s': ",
+                  name, bdrv_get_device_or_node_name(bs));
+    return false;
+}
diff --git a/block/qcow2.c b/block/qcow2.c
index b44fd64d12..80df8e040a 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3605,6 +3605,8 @@ BlockDriver bdrv_qcow2 = {
 
     .bdrv_detach_aio_context  = qcow2_detach_aio_context,
     .bdrv_attach_aio_context  = qcow2_attach_aio_context,
+
+    .bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap,
 };
 
 static void bdrv_qcow2_init(void)
diff --git a/block/qcow2.h b/block/qcow2.h
index 4e71e9f7c1..c4700ac65d 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -631,5 +631,9 @@ int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
                                   int64_t *refcount_table_size);
 bool qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
+bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
+                                      const char *name,
+                                      uint32_t granularity,
+                                      Error **errp);
 
 #endif
-- 
2.11.1