我的备份在此之后开始失败：
[2025-09-09 09:34:50] Creating archive: blah-forum-2025-09-09-093246-v20250828181952.tar.gz
[2025-09-09 09:34:50] Making sure archive does not already exist...
[2025-09-09 09:34:50] Creating empty archive...
[2025-09-09 09:34:50] EXCEPTION: tar --create --file /var/www/discourse/public/backups/default/blah-forum-2025-09-09-093246-v20250828181952.tar --files-from /dev/null
tar: /var/www/discourse/public/backups/default/mvertigo-org-vestibular-disorders-support-forum-2025-09-09-093246-v20250828181952.tar: Cannot open: Permission denied
tar: Error is not recoverable: exiting now
查看 web_only 容器内的权限：
/var/www/discourse/public/backups# ls -l
total 4
drwxr-xr-x 2 root root 4096 Sep 6 12:37 default
如果我查看另一个实例，所有权是不同的：
/var/www/discourse/public/backups# ls -l
total 4
drwxr-xr-x 2 discourse www-data 4096 Sep 9 03:46 default
这里出了什么问题，我应该为 web_only 容器更改该目录的什么设置——它应该与标准安装的设置相同吗？