This separates out the directory as returned from the graphdriver (the
"base" fs) from the root filesystem of the live container. This is
necessary as the "diff" operation needs access to the base filesystem
without all the mounts that the running container needs (/.dockerinit,
volumes, etc).
We change container in the following way:
Container.RootfsPath() returns the the directory which will be used as
the root in a running container. It is always of the form
"/var/lib/docker/container/<id>/root" and is a private bind mount to
the base filesystem. It is only available while the container is running.
Container.BasefsPath() returns the raw directory from the graph driver
without the container runtime mounts. It is availible whenever the
container is mounted (in between a container.Mount()/Unmount() pair,
which are properly refcounted).
This fixes issue #3840
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Upstream-commit: fab19d197c6cc362182f6cee4d0a6e65e799875f
Component: engine
6d81dd5d9b