if mountPoint.Type != sysfsDevice {
			continue
		}
		// Check whether sysfs is 'rw'
		if len(mountPoint.Opts) > 0 && mountPoint.Opts[0] == permWritable {
			return true, nil
		}
		logger.Error(nil, "Sysfs is not writable", "mountPoint", mountPoint, "mountOptions", mountPoint.Opts)
		return false, errReadOnlySysFS
	}

	return false, errors.New("no sysfs mounted")
}

func readIntStringFile(filename string) (int, error) {

				if err != nil { // Mostly not found error
					// Check if there is a parent device:
					//   e.g. if the mount is based on /dev/nvme0n1p1, let's calculate the
					//        real device name (nvme0n1) to get its sysfs information
					parentDevPath, e := os.Readlink("/sys/class/block/" + devName)
					if e == nil {
						parentDev := filepath.Base(filepath.Dir(parentDevPath))
						qst, err = bfs.SysBlockDeviceQueueStats(parentDev)
					}

// Kubernetes app process.
package app

import (
	"context"
	"errors"
	"fmt"
	goruntime "runtime"
	"strings"
	"time"

	"github.com/google/cadvisor/machine"
	"github.com/google/cadvisor/utils/sysfs"

	v1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/watch"

	featuregatetesting "k8s.io/component-base/featuregate/testing"
	"k8s.io/kubernetes/pkg/features"
	"k8s.io/kubernetes/pkg/volume/util/fsquota/common"
)

const dummyMountData = `sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
devtmpfs /dev devtmpfs rw,nosuid,size=6133536k,nr_inodes=1533384,mode=755 0 0
tmpfs /tmp tmpfs rw,nosuid,nodev 0 0

			},
			{
				Device: "/dev/hugepages",
				Type:   "hugetlbfs",
				Path:   "/mnt/hugepages-2Mi",
				Opts:   []string{"rw", "relatime", "pagesize=2Mi"},
			},
			{
				Device: "sysfs",
				Type:   "sysfs",
				Path:   "/sys",
				Opts:   []string{"rw", "nosuid", "nodev", "noexec", "relatime"},
			},
			{
				Device: "/dev/hugepages",
				Type:   "hugetlbfs",
				Path:   "/mnt/hugepages-1Gi",

// FD is a file descriptor. The net and os packages use this type as a
// field of a larger type representing a network connection or OS file.
type FD struct {
	// Lock sysfd and serialize access to Read and Write methods.
	fdmu fdMutex

	// System file descriptor. Immutable until Close.
	Sysfd int

	// Platform dependent state of the file descriptor.
	SysFile

	// I/O poller.
	pd pollDesc

	// Semaphore signaled when file is closed.

	case "tcp", "tcp4", "tcp6":
		return true
	}
	// ConnectEx windows API does not support connectionless sockets.
	return false
}

func newFD(sysfd syscall.Handle, family, sotype int, net string) (*netFD, error) {
	ret := &netFD{
		pfd: poll.FD{
			Sysfd:         sysfd,
			IsStream:      sotype == syscall.SOCK_STREAM,
			ZeroReadIsEOF: sotype != syscall.SOCK_DGRAM && sotype != syscall.SOCK_RAW,
		},
		family: family,

	}
	defer fd.decref()
	return ignoringEINTR(func() error {
		_, err := unix.Fcntl(fd.Sysfd, syscall.F_FULLFSYNC, 0)

		// There are scenarios such as SMB mounts where fcntl will fail
		// with ENOTSUP. In those cases fallback to fsync.
		// See #64215
		if err != nil && errors.Is(err, syscall.ENOTSUP) {
			err = syscall.Fsync(fd.Sysfd)
		}
		return err
	})

	//
	// WASI preview 1 lacks a dup(2) system call. When the os and net packages
	// need to share a file/socket, instead of duplicating the underlying file
	// descriptor, we instead provide a way to copy FD instances and manage the
	// underlying file descriptor with reference counting.
	RefCountPtr *int32

	// RefCount is the reference count of Sysfd. When a copy of an FD is made,

		return 0, err
	}
	defer dst.writeUnlock()
	if err := src.readLock(); err != nil {
		return 0, err
	}
	defer src.readUnlock()
	var n int
	for {
		n, err = unix.CopyFileRange(src.Sysfd, nil, dst.Sysfd, nil, max, 0)
		if err != syscall.EINTR {
			break
		}
	}
	return int64(n), err