Co-authored-by: @topherbullock

Bug Report

When Baggageclaim gets initialized with btrfs set as its device driver, sets up a disk image, a loopback device (finding or creating)

Steps to Reproduce

Here's what we did to repro this:

• Deployed the Helm Chart multiple times to our K8s cluster, with image tags to select a specific K8s node.
• Ran the following docker command against the K8s cluster (using the node the worker has been scheduled on)
  docker run -it --rm --privileged --pid=host justincormack/nsenter1

Expected Results

• We expected that there wouldn't be any loopback devices left behind on the host by worker containers which have been evicted from that node

Actual Results

• From the container, we verified that we could see ~250 loopback devices (loop1, loop2, etc..) losetup --list
• We also observed that these were definitely loopback devices set up for baggageclaim, as they were all (except the one in use) backed by a missing volumes.img

Additional Context

We started looking at this to address concerns associated with this issue in the Helm charts repo helm/charts#9668

Version Info

• Concourse version: 4.2.2
• Deployment type (BOSH/Docker/binary): K8s Helm Chart
• Infrastructure/IaaS: GKE
• Did this used to work? Probably not