Make it possible to select the volume driver

Use the same type of mounts for all the machine volumes.

The default could change in the future, depending on OS.

[NO NEW TESTS NEEDED]

Signed-off-by: Anders F Björklund <anders.f.bjorklund@gmail.com>

cmd/podman/machine/init.go

@@ -92,6 +92,10 @@ func init() {
 	flags.StringArrayVarP(&initOpts.Volumes, VolumeFlagName, "v", []string{}, "Volumes to mount, source:target")
 	_ = initCmd.RegisterFlagCompletionFunc(VolumeFlagName, completion.AutocompleteDefault)
 
+	VolumeDriverFlagName := "volume-driver"
+	flags.StringVar(&initOpts.VolumeDriver, VolumeDriverFlagName, "", "Optional volume driver")
+	_ = initCmd.RegisterFlagCompletionFunc(VolumeDriverFlagName, completion.AutocompleteDefault)
+
 	IgnitionPathFlagName := "ignition-path"
 	flags.StringVar(&initOpts.IgnitionPath, IgnitionPathFlagName, "", "Path to ignition file")
 	_ = initCmd.RegisterFlagCompletionFunc(IgnitionPathFlagName, completion.AutocompleteDefault)

docs/source/markdown/podman-machine-init.1.md

@@ -71,6 +71,10 @@ Podman mounts _host-dir_ in the host to _machine-dir_ in the Podman machine.
 The root filesystem is mounted read-only in the default operating system,
 so mounts must be created under the /mnt directory.
 
+#### **--volume-driver**
+
+Driver to use for mounting volumes from the host, such as `virtfs`.
+
 #### **--help**
 
 Print usage statement.

pkg/machine/config.go

@@ -19,6 +19,7 @@ type InitOptions struct {
 	IgnitionPath string
 	ImagePath    string
 	Volumes      []string
+	VolumeDriver string
 	IsDefault    bool
 	Memory       uint64
 	Name         string

pkg/machine/qemu/machine.go

@@ -172,8 +172,16 @@ func (v *MachineVM) Init(opts machine.InitOptions) (bool, error) {
 	// Add arch specific options including image location
 	v.CmdLine = append(v.CmdLine, v.addArchOptions()...)
 
-	// TODO: add to opts
-	volumeType := VolumeTypeVirtfs
+	var volumeType string
+	switch opts.VolumeDriver {
+	case "virtfs":
+		volumeType = VolumeTypeVirtfs
+	case "": // default driver
+		volumeType = VolumeTypeVirtfs
+	default:
+		err := fmt.Errorf("unknown volume driver: %s", opts.VolumeDriver)
+		return false, err
+	}
 
 	mounts := []Mount{}
 	for i, volume := range opts.Volumes {