I may have a work around for this problem.
tldr:
turn off Timeshift’s “Enable BTRFS qgroups (recommended)”
It’s in Settings –> Users. Sorry, cannot recommend this feature.
Then turn off btrfs’ quotas:
‘sudo btrfs quota disable .’
why:
btrfs-transacti & btrfs-cleaner appear to be related to the kernel, they don’t seem to be executables. They certainly are part of manjaro. It’s also difficult to see them in the various monitoring tools, but good old ‘top’ shows them fine.
I found this little quote from the btrfs IRC channel:
Zygo: quota is not on my “btrfs features that work” list
You can check to see if btrfs quotas are turned on using:
‘btrfs qgroup show .’
It is not well documented in the man pages, at least not in my opinion as you need to know to check the btrfs-qgroup man page instead of the btrfs-quota man page.
Without turning off the qgroups feature in Timeshift first, it does little good to turn quotas off manually, as Timeshift will turn them back on.
My system has been suffering for weeks, after figuring this out, it’s been running fine for the last day. No more mysterious freezes. Hopefully it will continue to stick. I figured it was worth weighing in on what I’d discovered, and hope this helps everyone else.
Also, I tried using various kernels 5.10, 5.9, & 5.4 but the problem remained.