Comment 5 for bug 1574363

Not sure if Docker, LXD, or btrfs. "user_subvol_rm_allowed" is enabled, issue only started appearing recently, unsure if due to Docker upgrade or LXD upgrade. Observed this error earlier but "user_subvol_rm_allowed" resolved it. However, with it enabled it still occurs now.

me@host: lxd --version
2.4.1

root@docker:~# docker info
Containers: 2
 Running: 0
 Paused: 0
 Stopped: 2
Images: 1
Server Version: 1.12.1
Storage Driver: btrfs
 Build Version: Btrfs v4.7
 Library Version: 101
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: null host bridge overlay
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Security Options: apparmor
Kernel Version: 4.4.0-43-generic
Operating System: Ubuntu 16.04.1 LTS
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 4 GiB
Name: docker
ID: FOAC:LFCO:6B2U:HWVU:NGEC:GZAS:ZKCI:EBIU:JDBP:EGB4:2NMN:4KXI
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
WARNING: No swap limit support
WARNING: bridge-nf-call-iptables is disabled
WARNING: bridge-nf-call-ip6tables is disabled
Insecure Registries:
 127.0.0.0/8

root@docker:~# docker --version
Docker version 1.12.1, build 23cf638

root@docker:~# mount | grep btrfs
/dev/md2 on / type btrfs (rw,relatime,space_cache,user_subvol_rm_allowed,subvolid=49300,subvol=/var/lib/lxd/containers/docker/rootfs)
/dev/md2 on /dev/lxd type btrfs (rw,relatime,space_cache,user_subvol_rm_allowed,subvolid=5,subvol=/var/lib/lxd/devlxd)
/dev/md2 on /dev/.lxd-mounts type btrfs (rw,relatime,space_cache,user_subvol_rm_allowed,subvolid=5,subvol=/var/lib/lxd/shmounts/docker)
/dev/md2 on /var/lib/docker/btrfs type btrfs (rw,relatime,space_cache,user_subvol_rm_allowed,subvolid=49300,subvol=/var/lib/lxd/containers/docker/rootfs/var/lib/docker/btrfs)

And finally, the error:

docker rm 681fbe3f6870
Error response from daemon: Driver btrfs failed to remove root filesystem 0c214cb543ccd067e5208c8d5374b8345ec534c54b488719f17adb5f6cd44821: Failed to rescan btrfs quota for &{}: operation not permitted