mounts: use path-based tags instead of index-based tags

pkg/cidata/cidata.go

@@ -203,8 +203,8 @@ func templateArgs(ctx context.Context, bootScripts bool, instDir, name string, i
 	if err != nil {
 		return nil, err
 	}
-	for i, f := range instConfig.Mounts {
-		tag := fmt.Sprintf("mount%d", i)
+	for _, f := range instConfig.Mounts {
+		tag := limayaml.MountTag(f.Location, *f.MountPoint)
 		options := "defaults"
 		switch fstype {
 		case "9p", "virtiofs":

pkg/driver/krunkit/krunkit_darwin_arm64.go

@@ -81,13 +81,13 @@ func Cmdline(inst *limatype.Instance) (*exec.Cmd, error) {
 
 	// File sharing commands
 	if *inst.Config.MountType == limatype.VIRTIOFS {
-		for i, mount := range inst.Config.Mounts {
+		for _, mount := range inst.Config.Mounts {
 			if _, err := os.Stat(mount.Location); errors.Is(err, os.ErrNotExist) {
 				if err := os.MkdirAll(mount.Location, 0o750); err != nil {
 					return nil, err
 				}
 			}
-			tag := fmt.Sprintf("mount%d", i)
+			tag := limayaml.MountTag(mount.Location, *mount.MountPoint)
 			mountArg := fmt.Sprintf("virtio-fs,sharedDir=%s,mountTag=%s", mount.Location, tag)
 			args = append(args, "--device", mountArg)
 		}

pkg/driver/qemu/qemu.go

@@ -936,7 +936,7 @@ func Cmdline(ctx context.Context, cfg Config) (exe string, args []string, err er
 
 	if *y.MountType == limatype.NINEP || *y.MountType == limatype.VIRTIOFS {
 		for i, f := range y.Mounts {
-			tag := fmt.Sprintf("mount%d", i)
+			tag := limayaml.MountTag(f.Location, *f.MountPoint)
 			if err := os.MkdirAll(f.Location, 0o755); err != nil {
 				return "", nil, err
 			}

pkg/driver/vz/vm_darwin.go

@@ -575,7 +575,7 @@ func attachDisplay(inst *limatype.Instance, vmConfig *vz.VirtualMachineConfigura
 func attachFolderMounts(inst *limatype.Instance, vmConfig *vz.VirtualMachineConfiguration) error {
 	var mounts []vz.DirectorySharingDeviceConfiguration
 	if *inst.Config.MountType == limatype.VIRTIOFS {
-		for i, mount := range inst.Config.Mounts {
+		for _, mount := range inst.Config.Mounts {
 			if _, err := os.Stat(mount.Location); errors.Is(err, os.ErrNotExist) {
 				err := os.MkdirAll(mount.Location, 0o750)
 				if err != nil {
@@ -592,7 +592,7 @@ func attachFolderMounts(inst *limatype.Instance, vmConfig *vz.VirtualMachineConf
 				return err
 			}
 
-			tag := fmt.Sprintf("mount%d", i)
+			tag := limayaml.MountTag(mount.Location, *mount.MountPoint)
 			config, err := vz.NewVirtioFileSystemDeviceConfiguration(tag)
 			if err != nil {
 				return err

pkg/limayaml/defaults.go

@@ -92,6 +92,13 @@ func MACAddress(uniqueID string) string {
 	return hw.String()
 }
 
+// MountTag generates a stable mount tag from location and mountPoint.
+// Both paths are hashed to handle the same location mounted to multiple mount points.
+func MountTag(location, mountPoint string) string {
+	sha := sha256.Sum256([]byte(location + "\x00" + mountPoint))
+	return fmt.Sprintf("lima-%x", sha[0:8])
+}
+
 func defaultCPUs() int {
 	const x = 4
 	if hostCPUs := runtime.NumCPU(); hostCPUs < x {

pkg/limayaml/defaults_test.go

@@ -842,3 +842,48 @@ func TestStaticPortForwarding(t *testing.T) {
 		})
 	}
 }
+
+func TestMountTag(t *testing.T) {
+	tests := []struct {
+		name       string
+		location   string
+		mountPoint string
+	}{
+		{"home directory", "/Users/testuser", "/Users/testuser"},
+		{"nested path", "/Users/testuser/Development/project", "/mnt/project"},
+		{"root path", "/", "/mnt/root"},
+		{"tmp directory", "/tmp/lima", "/tmp/lima"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tag := MountTag(tt.location, tt.mountPoint)
+			assert.Assert(t, len(tag) > 5 && tag[:5] == "lima-")
+			assert.Assert(t, len(tag) <= 36)
+			assert.Equal(t, tag, MountTag(tt.location, tt.mountPoint))
+		})
+	}
+}
+
+func TestMountTagUniqueness(t *testing.T) {
+	mounts := []struct{ location, mountPoint string }{
+		{"/Users/user1", "/Users/user1"},
+		{"/Users/user2", "/Users/user2"},
+		{"/home/user1", "/home/user1"},
+		{"/mnt/data", "/mnt/data"},
+		{"/tmp/lima", "/tmp/lima"},
+	}
+	tags := make(map[string]bool)
+	for _, m := range mounts {
+		tag := MountTag(m.location, m.mountPoint)
+		assert.Assert(t, !tags[tag], "tag collision: %s", tag)
+		tags[tag] = true
+	}
+}
+
+func TestMountTagDuplicateLocation(t *testing.T) {
+	location := "/Users/testuser"
+	tag1 := MountTag(location, "/home/user")
+	tag2 := MountTag(location, "/mnt/home-writable")
+	assert.Assert(t, tag1 != tag2)
+}