qcow2: add .bdrv_can_store_new_dirty_bitmap

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>
Message-id: 20170628120530.31251-23-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index f82478c..a8c7e1d 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -1388,3 +1388,54 @@ int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp)
 
     return 0;
 }
+
+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;
+}