Update Mount/Unmount arguments

Since [1], Mount() and Unmount() calls have their own structures.
Update our code accordingly.

[1] docker/go-plugins-helpers@461a12724a063

Signed-off-by: Kir Kolyshkin <[email protected]>

driver.go

@@ -228,7 +228,7 @@ func (d *ploopDriver) Remove(r volume.Request) volume.Response {
 	return volume.Response{}
 }
 
-func (d *ploopDriver) Mount(r volume.Request) volume.Response {
+func (d *ploopDriver) Mount(r volume.MountRequest) volume.Response {
 	logrus.Debugf("Mounting volume %s", r.Name)
 
 	p, err := ploop.Open(d.dd(r.Name))
@@ -258,7 +258,7 @@ func (d *ploopDriver) Mount(r volume.Request) volume.Response {
 	return volume.Response{Mountpoint: mnt}
 }
 
-func (d *ploopDriver) Unmount(r volume.Request) volume.Response {
+func (d *ploopDriver) Unmount(r volume.UnmountRequest) volume.Response {
 	logrus.Debugf("Unmounting volume %s", r.Name)
 
 	p, err := ploop.Open(d.dd(r.Name))

fstype.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+	"syscall"
+)
+
+// Given a file or directory, finds which filesystem it is on,
+// by parsing /proc/self/mountinfo and comparing dev_t
+// of the file to that in the mountinfo field.
+func GetFilesystemType(path string) (string, error) {
+	var st syscall.Stat_t
+
+	err := syscall.Stat(path, &st)
+	if err != nil {
+		return "", err
+	}
+
+	return getFSTypeByDev(st.Dev)
+}
+
+// convert minor:major string from /proc/self/mountinfo into dev_t
+func parseDev(s string) uint64 {
+	var major uint32
+	var minor uint32
+
+	n, _ := fmt.Sscanf(s, "%d:%d", &major, &minor)
+
+	if n != 2 {
+		return 0
+	}
+
+	return uint64(major<<8 + minor)
+}
+
+func getFSTypeByDev(dev uint64) (string, error) {
+	mi, err := os.Open("/proc/self/mountinfo")
+	if err != nil {
+		return "", err
+	}
+	defer mi.Close()
+
+	sc := bufio.NewScanner(mi)
+	for sc.Scan() {
+		line := strings.Split(sc.Text(), " ")
+		if len(line) < 10 {
+			return "", fmt.Errorf("Short line in /proc/self/mountinfo: %v\n", line)
+		}
+		dstr := line[2] // major:minor: value of st_dev for files on filesystem
+		fs := line[8]   // filesystem type:  name of filesystem of the form "type[.subtype]"
+		d := parseDev(dstr)
+		if d == 0 {
+			return "", fmt.Errorf("Can't parse device %s", dstr)
+		}
+		if d == dev {
+			return fs, nil
+		}
+	}
+
+	return "", nil
+}