How to set the default group, file permissions, and folder permissions, for an ext4 mount point?

Question

I have an ext4 disk/partition on my machine and I want to make it so, by default:

All files/folders have the group set to groupA
All files have:
- user permissions rw
- group permissions rw so folks in groupA can read and edit files
- no other permissions
All folders have:
- user permissions rwx
- group permissions rwx so folks in groupA can list folders and create new files/folders in them
- no other permissions

I thought I could do this with umask and gid in /etc/fstab but ext4 file systems do not support them.

If this matters, this is a fresh install of Debian.

I am not using ACLs and would prefer not to if possible.

Does changing permissions on the mount point (after the partition is mounted) give you what you need? — ajgringo619, Dec 14 '20 at 05:36
Yes. I can do it manually but I am trying to find a way to do this automatically for all files/folders created. — IMTheNachoMan, Dec 14 '20 at 05:39
Does this help: https://unix.stackexchange.com/questions/115631/getting-new-files-to-inherit-group-permissions-on-linux — ajgringo619, Dec 14 '20 at 05:48
Besides ACLs this is not managed by the file system at all. The mount options you have found are not defaults they are used for filesystems that don't have permissions at all like FAT32. Besides ACLs this is only controlled by the user process. So ACLs are you own option. See here https://unix.stackexchange.com/a/1315/20140 — Philip Couling, Dec 14 '20 at 11:18
@ajgringo619 No, it doesn't. Not completely. It doesn't address the default file permissions part. — IMTheNachoMan, Dec 14 '20 at 17:34

0 Answers0