ImageBuild: failed to compute cache key. when using ZFS as Storage Driver

Environment

 Server Version: 19.03.8
 Storage Driver: zfs
 Kernel Version: 5.4.0-42-generic
 Tilt.dev version: v0.17.2 (but also happens with older versions)

It only happens when using ZFS as storage driver.

Sample

https://github.com/sdelrio/tiltdev-issue-zfs

Dockerfiles used in tilt

• prometheus/Dockerfile

FROM prom/prometheus:v2.15.1

COPY prometheus.yml /etc/prometheus/prometheus.yml

• grafan/Dockerfile

FROM grafana/grafana

COPY --chown=grafana:grafana ./provisioning/ /etc/grafana/provisioning/%

Logs when tilt up

• Streamlog

Successfully loaded Tiltfile (230.373436ms)
   prometheus │ 
   prometheus │ Initial Build • prometheus
   prometheus │ STEP 1/1 — Building Dockerfile: [tilt.dev/prometheus]
   prometheus │ Building Dockerfile:
   prometheus │   FROM prom/prometheus:v2.15.1
   prometheus │   
   prometheus │   COPY prometheus.yml /etc/prometheus/prometheus.yml
   prometheus │   
   prometheus │ 
   prometheus │ 
   prometheus │      Tarring context…
   prometheus │      Building image
      grafana │ 
      grafana │ Initial Build • grafana
      grafana │ STEP 1/1 — Building Dockerfile: [tilt.dev/grafana]
      grafana │ Building Dockerfile:
      grafana │   FROM grafana/grafana
      grafana │   
      grafana │   COPY --chown=grafana:grafana ./provisioning/ /etc/grafana/provisioning/
      grafana │ 
      grafana │      Tarring context…
      grafana │      Building image
   prometheus │      copy /context /
      grafana │      copy /context /
      grafana │      copy /context / [done: 229ms]
   prometheus │      copy /context / [done: 272ms]
      grafana │      [1/2] FROM docker.io/grafana/grafana@sha256:d984df30a059aa8a4782f3cf316882c38a1a509b4ef83132658301d7a53761ee
      grafana │      [2/2] COPY --chown=grafana:grafana ./provisioning/ /etc/grafana/provisioning/
      grafana │      
      grafana │      ERROR IN: [2/2] COPY --chown=grafana:grafana ./provisioning/ /etc/grafana/provisioning/
      grafana │ 
      grafana │ got unexpected error during build/deploy: ImageBuild: failed to compute cache key: failed to mount /var/lib/docker/tmp/buildkit-mount018555909: [{Type:bind Source:/var/lib/docker/zfs/graph/vag0xqoutppmvli7u640kbpjh Options:[rbind ro]}]: no such file or directory
      grafana │ ERROR: Build Failed: ImageBuild: failed to compute cache key: failed to mount /var/lib/docker/tmp/buildkit-mount018555909: [{Type:bind Source:/var/lib/docker/zfs/graph/vag0xqoutppmvli7u640kbpjh Options:[rbind ro]}]: no such file or directory
   prometheus │      [1/2] FROM docker.io/prom/prometheus:v2.15.1@sha256:169b743ceb4452266915272f9c3409d36972e41cb52f3f28644e6c0609fc54e6
   prometheus │      [2/2] COPY prometheus.yml /etc/prometheus/prometheus.yml
   prometheus │      
   prometheus │      ERROR IN: [2/2] COPY prometheus.yml /etc/prometheus/prometheus.yml
   prometheus │ 
   prometheus │ got unexpected error during build/deploy: ImageBuild: failed to compute cache key: failed to mount /var/lib/docker/tmp/buildkit-mount052540832: [{Type:bind Source:/var/lib/docker/zfs/graph/qjkwdftokr44yhvmoh0fec30r Options:[rbind ro]}]: no such file or directory
   prometheus │ ERROR: Build Failed: ImageBuild: failed to compute cache key: failed to mount /var/lib/docker/tmp/buildkit-mount052540832: [{Type:bind Source:/var/lib/docker/zfs/graph/qjkwdftokr44yhvmoh0fec30r Options:[rbind ro]}]: no such file or directory

When DOCKER_BUILKIT is disabled

When DOCKER_BUILDKIT=0 tilt up It builds correctly

Start with the linked sample and the prometheus/Dockerfile and grafan/Dockerfile under the reported ZFS storage-driver environment. Reproduce the BuildKit failure with tilt up, then compare it with DOCKER_BUILDKIT=0; done means both Dockerfiles build successfully with BuildKit enabled.