Support nvme devices.

fs.go

@@ -22,9 +22,11 @@ import (
 	"errors"
 	"fmt"
 	"io/ioutil"
+	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
+	"syscall"
 
 	"golang.org/x/sys/unix"
 )
@@ -61,14 +63,20 @@ func (e fsResizer) String() string {
 func (e fsResizer) DepResizer() (Resizer, error) {
 	// TODO: use /proc/devices instead and stat the thing to
 	// figure out what it is, rather than using its name.
-	if strings.HasPrefix(e.fs.dev, "/dev/sd") && devEndsInNumber(e.fs.dev) {
-		return partitionResizer(e.fs.dev), nil
+	dev := e.fs.dev
+	if dev == "/dev/root" {
+		return nil, errors.New("unexpected device /dev/root from statFS")
 	}
-	if strings.HasPrefix(e.fs.dev, "/dev/mapper") ||
-		strings.HasPrefix(filepath.Base(e.fs.dev), "dm-") {
-		return lvResizer(e.fs.dev), nil
+	if (strings.HasPrefix(dev, "/dev/sd") || strings.HasPrefix(dev, "/dev/nvme")) &&
+		devEndsInNumber(dev) {
+		vlogf("fsResizer.DepResizer: returning partitionResizer(%q)", dev)
+		return partitionResizer(dev), nil
 	}
-	return nil, fmt.Errorf("don't know how to resize block device %q", e.fs.dev)
+	if strings.HasPrefix(dev, "/dev/mapper") ||
+		strings.HasPrefix(filepath.Base(dev), "dm-") {
+		return lvResizer(dev), nil
+	}
+	return nil, fmt.Errorf("don't know how to resize block device %q", dev)
 }
 
 func (e fsResizer) Resize() error {
@@ -121,8 +129,40 @@ func statFS(mnt string) (fs fsStat, err error) {
 			fs.mnt = mnt
 			fs.dev = f[0]
 			fs.fstype = f[2]
-			return fs, nil
+			if fs.dev == "/dev/root" {
+				dev, err := findDevRoot()
+				if err != nil {
+					return fs, fmt.Errorf("failed to map /dev/root to real device: %v", err)
+				}
+				fs.dev = dev
+			}
+			return fs, err
 		}
 	}
 	return fs, errors.New("mount point not found")
 }
+
+// findDevRoot finds which block device (e.g. "/dev/nvme0n1p1") patches the device number of /dev/root.
+func findDevRoot() (string, error) {
+	fis, err := ioutil.ReadDir("/dev")
+	if err != nil {
+		return "", err
+	}
+	dev := map[string]uint64{}
+	for _, fi := range fis {
+		if fi.Mode()&os.ModeDevice == 0 || fi.Mode()&os.ModeCharDevice != 0 {
+			continue
+		}
+		dev[fi.Name()] = fi.Sys().(*syscall.Stat_t).Rdev
+	}
+	wantDevnum, ok := dev["root"]
+	if !ok {
+		return "", errors.New("/dev/root not found in /dev")
+	}
+	for baseName, devNum := range dev {
+		if devNum == wantDevnum && baseName != "root" {
+			return "/dev/" + baseName, nil
+		}
+	}
+	return "", errors.New("no block device in /dev had device number like /dev/root")
+}

go.mod

@@ -1,5 +1,7 @@
 module github.com/google/embiggen-disk
 
+go 1.15
+
 require (
 	github.com/u-root/u-root v0.0.0-20180806213625-12f9029297cf
 	golang.org/x/sys v0.0.0-20180727230415-bd9dbc187b6e

main.go

@@ -51,6 +51,12 @@ func fatalf(format string, args ...interface{}) {
 	log.Fatalf(format, args...)
 }
 
+func vlogf(format string, args ...interface{}) {
+	if *verbose {
+		log.Printf(format, args...)
+	}
+}
+
 func main() {
 	flag.Parse()
 	if flag.NArg() != 1 {
@@ -62,6 +68,7 @@ func main() {
 
 	mnt := flag.Arg(0)
 	e, err := getFileSystemResizer(mnt)
+	vlogf("getFileSystemResizer(%q) = %#v, %v", mnt, e, err)
 	if err != nil {
 		fatalf("error preparing to enlarge %s: %v", mnt, err)
 	}

part.go

@@ -48,10 +48,17 @@ func diskDev(partDev string) string {
 	if !strings.HasPrefix(partDev, "/dev/") {
 		panic("bogus partition dev " + partDev)
 	}
-	if !strings.HasPrefix(partDev, "/dev/sd") {
-		panic("TODO: handle other device types; ask kernel")
+	if strings.HasPrefix(partDev, "/dev/sd") {
+		return strings.TrimRight(partDev, "0123456789")
 	}
-	return strings.TrimRight(partDev, "0123456789")
+	if strings.HasPrefix(partDev, "/dev/nvme") {
+		chopP := regexp.MustCompile(`p\d+$`)
+		if !chopP.MatchString(partDev) {
+			panic(fmt.Sprintf("partition %q doesn't look like an nvme partition", partDev))
+		}
+		return chopP.ReplaceAllString(partDev, "")
+	}
+	panic(fmt.Sprintf("Unsupport device %q; TODO: handle other device types; ask kernel", partDev))
 }
 
 func (p partitionResizer) String() string { return fmt.Sprintf("partition %s", string(p)) }
@@ -67,12 +74,15 @@ func (p partitionResizer) State() (string, error) {
 func (p partitionResizer) DepResizer() (Resizer, error) { return nil, nil }
 
 func (p partitionResizer) Resize() error {
+	vlogf("Resizing partition %q ...", string(p))
 	partDev := string(p)
 	diskDev := diskDev(partDev)
+	vlogf("Getting partition table for %q ...", diskDev)
 	pt := getPartitionTable(diskDev)
 	if len(pt.parts) == 0 {
 		log.Fatalf("device %q has no partitions", diskDev)
 	}
+	vlogf("Device %q has %d partitions.", diskDev, len(pt.parts))
 	var isGPT bool
 	switch t := pt.Meta("label"); t {
 	case "dos":
@@ -127,7 +137,7 @@ func (p partitionResizer) Resize() error {
 		fmt.Println()
 	}
 
-	size, err := readInt64File("/sys/block/sda/size")
+	size, err := readInt64File("/sys/block/" + filepath.Base(diskDev) + "/size")
 	if err != nil {
 		return err
 	}
@@ -329,7 +339,7 @@ func getPartitionTable(dev string) *partitionTable {
 	pt := new(partitionTable)
 	out, err := exec.Command("/sbin/sfdisk", "-d", dev).Output()
 	if err != nil {
-		log.Fatal(err)
+		log.Fatalf("running sfdisk -f %s: %v, %s", dev, err, out)
 	}
 	lines := strings.Split(string(out), "\n")
 	var pno int