Use faster mountinfo parser (part 1)

.travis.yml

@@ -1,25 +1,24 @@
 dist: bionic
 language: go
 go:
-  - 1.12.x
+  - 1.14.x
   - 1.13.x
-  - 1.x
   - tip
 
 matrix:
   include:
-    - go: 1.x
+    - go: 1.13.x
       name: "verify-dependencies"
       script:
         - make verify-dependencies
-    - go: 1.12.x
+    - go: 1.13.x
       name: "cgroup-systemd"
       env:
         - RUNC_USE_SYSTEMD=1
       script:
         - make BUILDTAGS="${BUILDTAGS}" all
         - sudo PATH="$PATH" make localintegration RUNC_USE_SYSTEMD=1
-    - go: 1.12.x
+    - go: 1.13.x
       name: "cgroup-v2"
       env:
         - VIRTUALBOX_VERSION=6.0

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.12-stretch
+FROM golang:1.13-stretch
 
 RUN dpkg --add-architecture armel \
     && dpkg --add-architecture armhf \

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/docker/go-units v0.3.3
 	github.com/godbus/dbus v0.0.0-20181101234600-2ff6f7ffd60f
 	github.com/golang/protobuf v1.0.0
+	github.com/moby/sys/mountinfo v0.1.0
 	github.com/mrunalp/fileutils v0.0.0-20171103030105-7d4729fb3618
 	github.com/opencontainers/runtime-spec v1.0.2-0.20190207185410-29686dbc5559
 	github.com/opencontainers/selinux v1.3.3

go.sum

@@ -18,6 +18,8 @@ github.com/golang/protobuf v1.0.0 h1:lsek0oXi8iFE9L+EXARyHIjU5rlWIhhTkjDz3vHhWWQ
 github.com/golang/protobuf v1.0.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
+github.com/moby/sys/mountinfo v0.1.0 h1:r8vMRbMAFEAfiNptYVokP+nfxPJzvRuia5e2vzXtENo=
+github.com/moby/sys/mountinfo v0.1.0/go.mod h1:w2t2Avltqx8vE7gX5l+QiBKxODu2TX0+Syr3h52Tw4o=
 github.com/mrunalp/fileutils v0.0.0-20171103030105-7d4729fb3618 h1:7InQ7/zrOh6SlFjaXFubv0xX0HsuC9qJsdqm7bNQpYM=
 github.com/mrunalp/fileutils v0.0.0-20171103030105-7d4729fb3618/go.mod h1:x8F1gnqOkIEiO4rqoeEEEqQbo7HjGMTvyoq3gej4iT0=
 github.com/opencontainers/runtime-spec v1.0.2-0.20190207185410-29686dbc5559 h1:Cef96rKLuXxeGzERI/0ve9yAzIeTpx0qz9JKFDZALYw=

libcontainer/factory_linux.go

@@ -11,15 +11,15 @@ import (
 	"runtime/debug"
 	"strconv"
 
-	"github.com/cyphar/filepath-securejoin"
+	securejoin "github.com/cyphar/filepath-securejoin"
+	"github.com/moby/sys/mountinfo"
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"github.com/opencontainers/runc/libcontainer/cgroups/fs"
 	"github.com/opencontainers/runc/libcontainer/cgroups/fs2"
 	"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/opencontainers/runc/libcontainer/configs/validate"
 	"github.com/opencontainers/runc/libcontainer/intelrdt"
-	"github.com/opencontainers/runc/libcontainer/mount"
 	"github.com/opencontainers/runc/libcontainer/utils"
 	"github.com/pkg/errors"
 
@@ -137,7 +137,7 @@ func IntelRdtFs(l *LinuxFactory) error {
 
 // TmpfsRoot is an option func to mount LinuxFactory.Root to tmpfs.
 func TmpfsRoot(l *LinuxFactory) error {
-	mounted, err := mount.Mounted(l.Root)
+	mounted, err := mountinfo.Mounted(l.Root)
 	if err != nil {
 		return err
 	}

libcontainer/factory_linux_test.go

@@ -9,8 +9,8 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/moby/sys/mountinfo"
 	"github.com/opencontainers/runc/libcontainer/configs"
-	"github.com/opencontainers/runc/libcontainer/mount"
 	"github.com/opencontainers/runc/libcontainer/utils"
 	"github.com/opencontainers/runtime-spec/specs-go"
 
@@ -101,33 +101,28 @@ func TestFactoryNewTmpfs(t *testing.T) {
 	if factory.Type() != "libcontainer" {
 		t.Fatalf("unexpected factory type: %q, expected %q", factory.Type(), "libcontainer")
 	}
-	mounted, err := mount.Mounted(lfactory.Root)
+	mounted, err := mountinfo.Mounted(lfactory.Root)
 	if err != nil {
 		t.Fatal(err)
 	}
 	if !mounted {
 		t.Fatalf("Factory Root is not mounted")
 	}
-	mounts, err := mount.GetMounts()
+	mounts, err := mountinfo.GetMounts(mountinfo.SingleEntryFilter(lfactory.Root))
 	if err != nil {
 		t.Fatal(err)
 	}
-	var found bool
-	for _, m := range mounts {
-		if m.Mountpoint == lfactory.Root {
-			if m.Fstype != "tmpfs" {
-				t.Fatalf("Fstype of root: %s, expected %s", m.Fstype, "tmpfs")
-			}
-			if m.Source != "tmpfs" {
-				t.Fatalf("Source of root: %s, expected %s", m.Source, "tmpfs")
-			}
-			found = true
-		}
-	}
-	if !found {
+	if len(mounts) != 1 {
 		t.Fatalf("Factory Root is not listed in mounts list")
 	}
-	defer unix.Unmount(root, unix.MNT_DETACH)
+	m := mounts[0]
+	if m.Fstype != "tmpfs" {
+		t.Fatalf("Fstype of root: %s, expected %s", m.Fstype, "tmpfs")
+	}
+	if m.Source != "tmpfs" {
+		t.Fatalf("Source of root: %s, expected %s", m.Source, "tmpfs")
+	}
+	unix.Unmount(root, unix.MNT_DETACH)
 }
 
 func TestFactoryLoadNotExists(t *testing.T) {

libcontainer/rootfs_linux.go

@@ -14,10 +14,10 @@ import (
 	"time"
 
 	securejoin "github.com/cyphar/filepath-securejoin"
+	"github.com/moby/sys/mountinfo"
 	"github.com/mrunalp/fileutils"
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"github.com/opencontainers/runc/libcontainer/configs"
-	"github.com/opencontainers/runc/libcontainer/mount"
 	"github.com/opencontainers/runc/libcontainer/system"
 	libcontainerUtils "github.com/opencontainers/runc/libcontainer/utils"
 	"github.com/opencontainers/selinux/go-selinux/label"
@@ -661,46 +661,26 @@ func mknodDevice(dest string, node *configs.Device) error {
 	return unix.Chown(dest, int(node.Uid), int(node.Gid))
 }
 
-func getMountInfo(mountinfo []*mount.Info, dir string) *mount.Info {
-	for _, m := range mountinfo {
-		if m.Mountpoint == dir {
-			return m
-		}
-	}
-	return nil
-}
-
 // Get the parent mount point of directory passed in as argument. Also return
 // optional fields.
 func getParentMount(rootfs string) (string, string, error) {
-	var path string
-
-	mountinfos, err := mount.GetMounts()
+	mi, err := mountinfo.GetMounts(mountinfo.ParentsFilter(rootfs))
 	if err != nil {
 		return "", "", err
 	}
-
-	mountinfo := getMountInfo(mountinfos, rootfs)
-	if mountinfo != nil {
-		return rootfs, mountinfo.Optional, nil
+	if len(mi) < 1 {
+		return "", "", fmt.Errorf("could not find parent mount of %s", rootfs)
 	}
 
-	path = rootfs
-	for {
-		path = filepath.Dir(path)
-
-		mountinfo = getMountInfo(mountinfos, path)
-		if mountinfo != nil {
-			return path, mountinfo.Optional, nil
-		}
-
-		if path == "/" {
-			break
+	// find the longest mount point
+	var idx, maxlen int
+	for i := range mi {
+		if len(mi[i].Mountpoint) > maxlen {
+			maxlen = len(mi[i].Mountpoint)
+			idx = i
 		}
 	}
-
-	// If we are here, we did not find parent mount. Something is wrong.
-	return "", "", fmt.Errorf("Could not find parent mount of %s", rootfs)
+	return mi[idx].Mountpoint, mi[idx].Optional, nil
 }
 
 // Make parent mount private if it was shared
@@ -825,25 +805,22 @@ func pivotRoot(rootfs string) error {
 }
 
 func msMoveRoot(rootfs string) error {
-	mountinfos, err := mount.GetMounts()
-	if err != nil {
-		return err
-	}
-
-	absRootfs, err := filepath.Abs(rootfs)
+	mountinfos, err := mountinfo.GetMounts(func(info *mountinfo.Info) (skip, stop bool) {
+		skip = false
+		stop = false
+		// Collect every sysfs and proc file systems, except those under the container rootfs
+		if (info.Fstype != "proc" && info.Fstype != "sysfs") || strings.HasPrefix(info.Mountpoint, rootfs) {
+			skip = true
+			return
+		}
+		return
+	})
 	if err != nil {
 		return err
 	}
 
 	for _, info := range mountinfos {
-		p, err := filepath.Abs(info.Mountpoint)
-		if err != nil {
-			return err
-		}
-		// Umount every syfs and proc file systems, except those under the container rootfs
-		if (info.Fstype != "proc" && info.Fstype != "sysfs") || filepath.HasPrefix(p, absRootfs) {
-			continue
-		}
+		p := info.Mountpoint
 		// Be sure umount events are not propagated to the host.
 		if err := unix.Mount("", p, "", unix.MS_SLAVE|unix.MS_REC, ""); err != nil {
 			return err