cifs storage solution UI buggy?

[nerdoc]

I am trying to use a FritzBox router with an attached USB storage (exported per smb3) as simple backup storage solution for my VMs. But I cant get Proxmox (6.4-15) to recognize that CIFS export correctly.
If I add a CIFS storage, the proxmox UI tells me: "create storage failed: storage 'backups_fritz_usb' is not online(500)'.
But if I have a look at the CLI:

$ mount
//192.168.178.1/BACKUPS on /mnt/pve/backups_fritz_usb type cifs (rw,relatime,vers=3.0,cache=strict,username=xxxxxx,uid=0,noforceuid,gid=0,noforcegid,addr=xx.xx.xx.xx,file_mode=0755,dir_mode=0755,soft,nounix,serverino,mapposix,rsize=65536,wsize=65536,bsize=1048576,echo_interval=60,actimeo=1)

So it IS mounted, and I can even ls the files in it. The Dialog even finds the share automatically.

So I can't really understand the error message.

But, the bigger problem, and maybe a bug? is that Proxmox does not unmount this faulty mount point again, so it stays there for not-good.

 

[nerdoc]

The next time, I get an error message:

create storage failed: mkdir /mnt/pve/backups_fritz_usb/dump:
Permission denied at /usr/share/perl5/PVE/Storage/Plugin.pm line 1175. (500)

Which I can't understand neither, as the directory actually gets created:

drwxr-xr-x 2 root   root          0 Aug  1 09:15 backups_fritz_usb

Adding it per CLI seems to do the trick...

pvesm add cifs backups_fritz_usb --server 192.168.178.1 --share BACKUPS --username xxxxx --password
Enter Password: ***********

Update:
I just found another another thread and a bug where subdirectories are not implemented (yet?) in cifs shares.
Maybe this could be related to this problem, as a AVM Fritzbox exports it's USB share per samba with a single share, and users can just access subdirectories of that. so the share is e.g. BACKUP, and within that, the usb disk is a directoy named INTENSO. this can't be changed.