No sync of folders with special group permissions in Linux

[Rotlux]

Feature request

On Manjaro Linux FreeFileSync is unable to sync the contents of shared folders with special group permissions rws
On my Manjaro Linux system there are two users "bartolo" and "egidio" who are using a shared folder with special group permissions (-> setgid flag) for shared files. I want to sync the contents of this shared folder to an external hard drive and then take the external hard drive to a remote PC for data sync. While this works with linux commands, FreeFileSync fails.

Example for this issue:
Source folder is `media` on PC SSD named "Thales"**

[bartolo@Thales media]$ ls -l
drwxrwsr-x 7 bartolo users 4096 20. Jul 22:05 media


Path:

[bartolo@Thales media]$ pwd 
/mnt/aethon/EDV/Computech_obv/Bildbearbeitung/media


Containing a subfolder with files of ownership user=egidio and group = users is to be mirrored by user bartolo:

drwxrwsr-x 2 egidio users 4096 5. Jun 15:41 Subfolder


with the files:

├── [drwxrwsr-x bartolo  users   ]  media
│   └── [drwxrwsr-x egidio   users   ]  Subfolder
│       ├── [-rw-rw-r-- egidio   users   ]  Farbtemperatur.jpg
│       ├── [-rw-rw-r-- egidio   users   ]  Mikrofoto_sharpening.jpg
│       ├── [-rw-rw-r-- egidio   users   ]  Dummy-1.txt
│       └── [-rw-rw-r-- egidio   users   ]  Dummy-2.txt


Destination folder is `media` with special group permissions on an external hard drive named "Palmira":

[bartolo@Thales media]$ ls -l
drwxrwsr-x 5 bartolo users 4096 22. Jul 22:51 media


Path:

[bartolo@Thales media]$ pwd 
/run/media/bartolo/Palmira/Backup/EDV-Crea_A/EDV/Computech_obv/Bildbearbeitung/media


FreeFileSync can't copy the contents to the destination folder on the external hard drive *"Palmira"*
FFS aborts with an error like this:
"Cannot write permissions ... not allowed [chown] -> see attachments

rsync can handle special group permissons
You can run the command as user without admin privileges:

rsync -aHAXS /mnt/aethon/EDV/ /run/media/bartolo/Palmira/Backup/EDV-Crea_A/EDV


The contents of the destination folder `media` on the external hard drive look like that after `rsync -AHAXS`

drwxrwsr-x 7 bartolo users 4096 20. Jul 22:05  media
[bartolo@bartolo-pc Bildbearbeitung]$ tree -pug
├── [drwxrwsr-x bartolo  users   ]  media
│   └── [drwxrwsr-x bartolo  users   ]  Subfolder
│       ├── [-rw-rw-r-- bartolo  users   ]  Farbtemperatur.jpg
│       ├── [-rw-rw-r-- bartolo  users   ]  Mikrofoto_sharpening.jpg
│       ├── [-rw-rw-r-- bartolo  users   ]  Dummy-1.txt
│       └── [-rw-rw-r-- bartolo  users   ]  Dummy-2.txt


Please add this functionality to FreeFileSync.

[Plerry]

Why not run the sync under separate user credentials for which you assign full permissions to said folders?

[Rotlux]

Both users "bartolo" and "egidio" belong to the group "users". Members of the group "users" have read and write permission for the files and folders mentioned above.
For linux commands (on CLI), there is no need for privilege escalation in this situation.