Bug 436658

SUMMARY
Just upgraded from 20.10 to 21.04.

Dolphin has a list in the left sidebar called 'Remote'. In this list I have network shares from fstab which will mount on first click. The shares are mounted successfully, but Dolphin somehow doesn't get it. It thinks they are not mounted and tries every time I click on the folder to mount them again despite being already mounted. When I navigate into a mounted share I can see all files but the "TiB/GiB free" indicator doesn't work too. It shows the free space on / and not the mounted share. I also have a nfs share where everything is working. Just cifs doesn't work.
Because of that I can't normally access the shares via the sidebar but if I open the path in dolphin manually it works.

Error message from dolphin: 

An error occurred while accessing 'Home', the system responded: mount error(16): Device or resource busy
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log messages (dmesg)

I don't know what 'Home' should be, I don't have a mount with that name.


dmesg:
[ 1465.972263] CIFS: Attempting to mount \\192.168....
[ 1693.215546] CIFS: Attempting to mount \\192.168....


STEPS TO REPRODUCE
1. Add cifs shares to /etc/fstab
2. try to mount them via dolphin
3. Mount is successful, Dolphin doesn't recognize it was successful

OBSERVED RESULT

Dolphin doesn't detect that they are already mounted.


EXPECTED RESULT

Dolphin should detect mounts.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 21.04
(available in About System)
KDE Plasma Version: 5.21.4
KDE Frameworks Version: 5.80.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION