Hi guys,
My machine is failing to unmount old BTRFS subvolumes on shutdown forcing me to hit the reset button.
I dont have them mounted in fstab and they were actually temporary subvolumes which no longer exist due to me removing compression from my drives.
Where might they being referenced so i can clean up?
Bit odd.
Not sure if this can help but might give some idea:
systemctl --all | grep mount
This will list the systemd mount units(services?). There might be some leftovers?
Its odd. I cant see anything wrong in there.
When i fully remove plex media server, including scraping out all config files things return to normal.
As soon as i reinstall plex the errors are back.
The thing is those subvolumes dont exist any more but somehow they are being referenced.
sudo btrfs subvolume list /
ID 893 gen 93521 top level 5 path @no_cow
ID 1672 gen 93648 top level 5 path @cache
ID 1673 gen 93424 top level 5 path timeshift-btrfs/snapshots/2022-02-07_17-12-03/@
ID 1674 gen 93521 top level 5 path @games
ID 1675 gen 93574 top level 5 path @steam
ID 1676 gen 93649 top level 5 path @log
ID 1677 gen 93649 top level 5 path @home
ID 1848 gen 93424 top level 5 path timeshift-btrfs/snapshots/2022-02-03_16-00-02/@
ID 1849 gen 86825 top level 5 path timeshift-btrfs/snapshots/2022-02-03_16-00-02/@home
ID 1920 gen 93648 top level 5 path @pebcak
It looks like something to do with plex’s media scanning engine thinking it sees a mount point. The question is where is it finding them.
I think BTRFS was a red herring.
Adding shutdown to mkinitcpio.conf hooks fixed it as per a hour guides and discussions on the web but im not sure of the consequences just yet.
I see you got me encapsulated in a subvolume 
HAHA not sure how i managed that.
i’ll make sure your regularly snapshotted !
In less entertaining news the problem is back. People talk about UEFI mode vs CSM in the bios with this niggle and i did recently update my gfx card driver so i can run without CSM so it could be some sort of snag around this.
