I noticed some "%q!!missing!!" in my logs and found:
$ git grep 'f(.*, ".*%q.*")'
metadata/containers.go: return containers.Container{}, errors.Wrapf(errdefs.ErrNotFound, "bucket name %q")
metadata/containers.go: err = errors.Wrapf(errdefs.ErrAlreadyExists, "content %q")
metadata/namespaces.go: return errors.Wrapf(errdefs.ErrAlreadyExists, "namespace %q")
Signed-off-by: Ian Campbell <ian.campbell@docker.com>