Shared ccache directory between docker containers

Hello list.

Is it safe to share the ccache directory between docker containers wrt to
locking?

We use host mounts (i.e. not volumes) like this:

docker run -v
/var/tmp/docker-build-ccache:/var/tmp/docker-build-ccache my-compile-job

We sometimes see issues when simultaneous jobs are run.

docker storage Driver: aufs
Backing Filesystem: extfs
ccache version 3.1.10

ccache: FATAL: Failed to open
/var/tmp/docker-build-ccache/tmp/tmp.cpp_stderr.docker-host.21810: No such
file or directory

The hostname of these concurrent containers is the same. PID:s in docker
are translated (they are in their own PID namespace).