This took me way longer to figure out than I expected, so I wanted to add it here for anyone else banging their head against the wall.
Issue: I added a second drive (nvme internal) to my PC (Fedora 43 KDE) and formatted it ext4. After restarting, the drive would not be mounted but was listed in the Dolphin sidebar. Clicking that would prompt my admin password, then the drive would work perfectly as a Steam Library drive. However, I wanted it to mount automatically without prompting for my password, and there are many posts online about how to do this via KDE Partition Manager or by editing /etc/fstab. However, while these methods work for mounting a drive and making it read/write, Steam (installed through Discover, NOT flatpak) simply would not see it as a usable drive (Settings>Storage). I tried many pieces of advice from various online posts, and almost none included the oddly simple solution: Add “exec” to the /etc/fstab entry for the drive. So for example:
You can also do this using KDE Partition Manager. Find the partition you are using, right click > Unmount (if mounted). Then right click again > Edit mount point. If you have not already created a mount point, do so here. Choose a path (for example /mnt/DiskName) and make sure to check “users can mount…” and “Don’t prevent…” then click “More…” type exec and click OK. This will create an entry in /etc/fstab similar to the one above.
From what I can tell, the location of the mountpoint doesn’t really matter (I tried /mnt/[MOUNTPOINT] and /home/[YOURUSER]/mnt/[MOUNTPOINT] and they both worked). It might be important that your user:group owns the mountpoint directory. I am not sure. KDE Partition Manager automatically makes your user:group the owner if you create a path that doesn’t already exist, so I didn’t need to change anything. It may also matter that exec is near the end of the list of options in the fstab listing. I have not tested all these scenarios, but that seemed to be an issue for some people.
This all could have been a lot easier if KDE Partition Manager had a checkbox for adding exec. Finding this solution took me hours because there are so many wild goose chases if you search for solutions to this issue.
If anyone knows a better way to achieve the same thing or if there’s a security reason not to add exec to a mounted internal drive, please let me know.
Yes it does. Options are applied from left to right, and users implies noexec, so to override that, you need to have exec after users. (This similar question on Ubuntu StackExchange covers it concisely.)
Is this a drive that you want to be mounted at boot and remain permanently mounted? If so, then you could just leave “Users can mount…” unselected.
If you don’t set the users option then there’s no implicit noexec, so no need to manually set exec.
That’s a decent idea. (Maybe it would make sense for that option to be greyed out unless you also selected “Users can mount…”) You could raise it as an enhancement request on the KDE bug tracker.
I tried KDE Partition Manager but apparently I’m too stupid to understand that program so I use Gnome Disk. With Gnome Disk it is 3 clicks and my second NVMe drive which has my Steam library auto mounts at start-up and Steam has no problems seeing/using it.
I’m certain one can do the same in fstab, but I’'m too lazy to mess around in that file when i can achieve the same in 3 mouse clicks.
Oh! Thank you for explaining that the users option sets noexec. I had no idea, and now it all makes sense. I’ve never filed a bug report before, but I’ll give it a shot. If the exec checkbox were grayed out unless the users box was checked, I think that could have helped me understand what was happening. I never tried mounting it without the users option because nearly every guide I found online included it. I assumed that since I was running Steam as a user it mattered. I’m still learning all of this. Thanks for your help.
Since I’m running KDE Fedora it came with KDE Partition Manager by default, so that’s the only reason I chose it over others. No idea if gnome users would have these issues.
A previous KDE bug report noted that the existing “no binary execution” checkbox does not add an exec option to fstab. So there’s a checkbox to not allow execution, but no box for adding execution. A comment to that bug suggested that it could instead be a tri-state selector: “noexec - leave unchanged - exec” with leave unchanged selected by default and with the same behavior as the current default. I like that solution as I am sure I would have tried ticking the exec option as one of my first troubleshooting steps. I have no idea if there would be unintended consequences, though, but I guess I’ll leave that to the KDE folks.