Created attachment 164271 [details]
qgroups are not being destroyed when the snapshots are. This makes btrfs-cleaner extremely slow when snapper-cleanup is run on a setup with 15 daily and 10 hourly snapshots. Every day when snapper-cleanup is run btrfs-cleaner consumes about 20 minutes of processor time and locks IO every 5-10 seconds for 5 second bursts. Disabling quotas seems to have solved this problem.
I had 2965 qgroups spread across three subvolumes according to `btrfs qgroup show /`. Attached output. cgroupid of the subvolumes are 257 (/, 30G), 258 (/home, 30G) and 259 (/data, 400G).
Running on laptop Sandy Bridge i3 @ 2.3GHz and 512GB Crucial M4 SSD.
Created attachment 164281 [details]
qgroup.c btrfs_delayed_qgroup_accounting error
Every time snapper-cleanup is run the kernel outputs an error trace regarding qgroup.c btrfs_delayed_qgroup_accounting. Attached kernel log snippet.
May be related to https://bugzilla.kernel.org/show_bug.cgi?id=81221
I also that qgroups don't get cleaned up. I'm on Fedora 22 4.1.5-200.fc22.x86_64.