Booksonic in Docking running on Synology NAS require SYSTEM rw permissions on folders

[DavidDjerf]

Problem description

Installed Booksonic in docker on my Synology NAS DS218+.
Previously running Jellyfin with no permission issues, but Booksonic say mounted Audiobook and Podcast folders are read only.

After som troubleshooting I found this post saying that adding rw to SYSTEM user will fix the problem... and it did.
So why is this a problem for Booksonic and not Jellyfin? I have no clue, but maybe you can take a look at this or just add it to the FAQ.

Steps to reproduce

1. Get a Synology NAS runnning DiskStation ver 7.01-42218 update 3
2. Install Docker
3. Install Booksonic-Air
4. Mount any new folder for Books and podcasts
5. Scream in frustration when the folder is read only for no reason

System information

Synology NAS runnning DiskStation ver 7.01-42218 update 3
Installed from: https://registry.hub.docker.com/r/linuxserver/booksonic-air/
Version 2201.1.0 – January 13, 2022, based on Airsonic 8b28366
Server Apache Tomcat/9.0.56, java 1.8.0_312, Linux

Additional notes