b8ed0bd0e3
This computes the space usage for mounted partitions. It takes in a list of mounted partitions from containerHints and computes the device's disk usage(so each mount must be a separate partition). This is useful for users who mount partitions on containers and store most of the container's persistent data on those partitions.
131 lines
3.3 KiB
Go
131 lines
3.3 KiB
Go
// +build linux
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//
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// Provides Filesystem Stats
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package fs
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/*
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extern int getBytesFree(const char *path, unsigned long long *bytes);
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extern int getBytesTotal(const char *path, unsigned long long *bytes);
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*/
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import "C"
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import (
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"fmt"
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"os/exec"
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"strconv"
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"strings"
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"syscall"
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"unsafe"
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"github.com/docker/docker/pkg/mount"
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"github.com/golang/glog"
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)
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type partition struct {
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mountpoint string
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major uint
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minor uint
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}
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type RealFsInfo struct {
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partitions map[string]partition
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}
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func NewFsInfo() (FsInfo, error) {
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mounts, err := mount.GetMounts()
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if err != nil {
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return nil, err
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}
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partitions := make(map[string]partition, 0)
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for _, mount := range mounts {
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if !strings.HasPrefix(mount.Fstype, "ext") {
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continue
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}
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// Avoid bind mounts.
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if _, ok := partitions[mount.Source]; ok {
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continue
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}
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partitions[mount.Source] = partition{mount.Mountpoint, uint(mount.Major), uint(mount.Minor)}
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}
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return &RealFsInfo{partitions}, nil
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}
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func (self *RealFsInfo) GetFsInfoForPath(mountSet map[string]bool) ([]Fs, error) {
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filesystems := make([]Fs, 0)
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deviceSet := make(map[string]bool)
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for device, partition := range self.partitions {
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if mountSet == nil || mountSet[partition.mountpoint] == true {
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total, free, err := getVfsStats(partition.mountpoint)
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if err != nil {
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glog.Errorf("Statvfs failed. Error: %v", err)
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} else if deviceSet[device] == false {
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deviceSet[device] = true
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deviceInfo := DeviceInfo{
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Device: device,
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Major: uint(partition.major),
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Minor: uint(partition.minor),
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}
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fs := Fs{deviceInfo, total, free}
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filesystems = append(filesystems, fs)
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}
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}
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}
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return filesystems, nil
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}
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func (self *RealFsInfo) GetGlobalFsInfo() ([]Fs, error) {
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return self.GetFsInfoForPath(nil)
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}
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func major(devNumber uint64) uint {
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return uint((devNumber >> 8) & 0xfff)
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}
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func minor(devNumber uint64) uint {
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return uint((devNumber & 0xff) | ((devNumber >> 12) & 0xfff00))
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}
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func (self *RealFsInfo) GetDirFsDevice(dir string) (*DeviceInfo, error) {
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var buf syscall.Stat_t
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err := syscall.Stat(dir, &buf)
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if err != nil {
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return nil, fmt.Errorf("stat failed on %s with error: %s", dir, err)
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}
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major := major(buf.Dev)
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minor := minor(buf.Dev)
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for device, partition := range self.partitions {
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if partition.major == major && partition.minor == minor {
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return &DeviceInfo{device, major, minor}, nil
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}
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}
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return nil, fmt.Errorf("could not find device with major: %d, minor: %d in cached partitions map", major, minor)
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}
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func (self *RealFsInfo) GetDirUsage(dir string) (uint64, error) {
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out, err := exec.Command("du", "-s", dir).CombinedOutput()
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if err != nil {
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return 0, fmt.Errorf("du command failed on %s with output %s - %s", dir, out, err)
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}
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usageInKb, err := strconv.ParseUint(strings.Fields(string(out))[0], 10, 64)
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if err != nil {
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return 0, fmt.Errorf("cannot parse 'du' output %s - %s", out, err)
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}
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return usageInKb * 1024, nil
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}
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func getVfsStats(path string) (total uint64, free uint64, err error) {
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_p0, err := syscall.BytePtrFromString(path)
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if err != nil {
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return 0, 0, err
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}
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res, err := C.getBytesFree((*C.char)(unsafe.Pointer(_p0)), (*_Ctype_ulonglong)(unsafe.Pointer(&free)))
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if res != 0 {
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return 0, 0, err
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}
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res, err = C.getBytesTotal((*C.char)(unsafe.Pointer(_p0)), (*_Ctype_ulonglong)(unsafe.Pointer(&total)))
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if res != 0 {
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return 0, 0, err
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}
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return total, free, nil
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}
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