After the very first init of the graph `docker info` correctly shows the
base fs type under `Backing Filesystem`. This information isn't stored
anywhere. After a restart (w/o erasing `/var/lib/docker`) `docker info`
shows an empty string under `Backing Filesystem`.
This patch records the base fs type after the first run in the metadata
or, to fix old devices that don't have this info in the metadata, just
probe the fs type of the base device at graph startup.
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
Upstream-commit: f22ee02c6d6bd16f2179e71366ec641a7d234e96
Component: engine
bc2d1566f2