btrfs: use super write guard in sb_start_write()

Link: https://patch.msgid.link/20251104-work-guards-v1-4-5108ac78a171@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

fs/btrfs/volumes.c

@@ -4660,12 +4660,12 @@ static int balance_kthread(void *data)
 	struct btrfs_fs_info *fs_info = data;
 	int ret = 0;
 
-	sb_start_write(fs_info->sb);
+	guard(super_write)(fs_info->sb);
+
 	mutex_lock(&fs_info->balance_mutex);
 	if (fs_info->balance_ctl)
 		ret = btrfs_balance(fs_info, fs_info->balance_ctl, NULL);
 	mutex_unlock(&fs_info->balance_mutex);
-	sb_end_write(fs_info->sb);
 
 	return ret;
 }