376 lines
8.4 KiB
Go
376 lines
8.4 KiB
Go
![]() |
package zfs
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/*
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#include <locale.h>
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#include <stdlib.h>
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#include <dirent.h>
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#include <mntent.h>
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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"
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"os/exec"
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"path"
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"strconv"
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"strings"
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"syscall"
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"time"
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"unsafe"
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log "github.com/Sirupsen/logrus"
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"github.com/docker/docker/daemon/graphdriver"
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"github.com/docker/docker/pkg/archive"
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"github.com/docker/docker/pkg/ioutils"
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"github.com/docker/docker/pkg/parsers"
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zfs "github.com/mistifyio/go-zfs"
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)
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type ZfsOptions struct {
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fsName string
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mountPath string
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}
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func init() {
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graphdriver.Register("zfs", Init)
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}
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type Logger struct{}
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func (*Logger) Log(cmd []string) {
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log.Debugf("[zfs] %s", strings.Join(cmd, " "))
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}
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func Init(base string, opt []string) (graphdriver.Driver, error) {
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var err error
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options, err := parseOptions(opt)
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options.mountPath = base
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if err != nil {
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return nil, err
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}
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rootdir := path.Dir(base)
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if options.fsName == "" {
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err = checkRootdirFs(rootdir)
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if err != nil {
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return nil, err
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}
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}
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if _, err := exec.LookPath("zfs"); err != nil {
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return nil, fmt.Errorf("zfs command is not available")
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}
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file, err := os.OpenFile("/dev/zfs", os.O_RDWR, 600)
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defer file.Close()
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if err != nil {
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return nil, fmt.Errorf("Failed to initialize: %v", err)
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}
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if options.fsName == "" {
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options.fsName, err = lookupZfsDataset(rootdir)
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if err != nil {
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return nil, err
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}
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}
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logger := Logger{}
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zfs.SetLogger(&logger)
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dataset, err := zfs.GetDataset(options.fsName)
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if err != nil {
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return nil, fmt.Errorf("Cannot open %s", options.fsName)
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}
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return &Driver{
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dataset: dataset,
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options: options,
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}, nil
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}
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func parseOptions(opt []string) (ZfsOptions, error) {
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var options ZfsOptions
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options.fsName = ""
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for _, option := range opt {
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key, val, err := parsers.ParseKeyValueOpt(option)
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if err != nil {
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return options, err
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}
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key = strings.ToLower(key)
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switch key {
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case "zfs.fsname":
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options.fsName = val
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default:
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return options, fmt.Errorf("Unknown option %s\n", key)
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}
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}
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return options, nil
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}
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func checkRootdirFs(rootdir string) error {
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var buf syscall.Statfs_t
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if err := syscall.Statfs(rootdir, &buf); err != nil {
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fmt.Errorf("Failed to access '%s': %s", rootdir, err)
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}
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if graphdriver.FsMagic(buf.Type) != graphdriver.FsMagicZfs {
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log.Debugf("[zfs] no zfs dataset found for rootdir '%s'", rootdir)
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return graphdriver.ErrPrerequisites
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}
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return nil
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}
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var CprocMounts = C.CString("/proc/mounts")
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var CopenMod = C.CString("r")
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func lookupZfsDataset(rootdir string) (string, error) {
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var stat syscall.Stat_t
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var Cmnt C.struct_mntent
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var Cfp *C.FILE
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buf := string(make([]byte, 256, 256))
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Cbuf := C.CString(buf)
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defer free(Cbuf)
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if err := syscall.Stat(rootdir, &stat); err != nil {
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return "", fmt.Errorf("Failed to access '%s': %s", rootdir, err)
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}
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wantedDev := stat.Dev
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if Cfp = C.setmntent(CprocMounts, CopenMod); Cfp == nil {
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return "", fmt.Errorf("Failed to open /proc/mounts")
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}
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defer C.endmntent(Cfp)
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for C.getmntent_r(Cfp, &Cmnt, Cbuf, 256) != nil {
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dir := C.GoString(Cmnt.mnt_dir)
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if err := syscall.Stat(dir, &stat); err != nil {
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log.Debugf("[zfs] failed to stat '%s' while scanning for zfs mount: %v", dir, err)
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continue // may fail on fuse file systems
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}
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fs := C.GoString(Cmnt.mnt_type)
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if stat.Dev == wantedDev && fs == "zfs" {
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return C.GoString(Cmnt.mnt_fsname), nil
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}
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}
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// should never happen
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return "", fmt.Errorf("Failed to find zfs pool in /proc/mounts")
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}
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func free(p *C.char) {
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C.free(unsafe.Pointer(p))
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}
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type Driver struct {
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dataset *zfs.Dataset
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options ZfsOptions
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}
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func (d *Driver) String() string {
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return "zfs"
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}
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func (d *Driver) Cleanup() error {
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return nil
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}
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func (d *Driver) Status() [][2]string {
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parts := strings.Split(d.dataset.Name, "/")
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pool, err := zfs.GetZpool(parts[0])
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if err != nil {
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return [][2]string{
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{"error while getting pool", fmt.Sprintf("%v", err)},
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}
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}
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var quota string
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if d.dataset.Quota == 0 {
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quota = strconv.FormatUint(d.dataset.Quota, 10)
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} else {
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quota = "no"
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}
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return [][2]string{
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{"Zpool", pool.Name},
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{"Zpool Health", pool.Health},
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{"Parent Dataset", d.dataset.Name},
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{"Space Used By Parent", strconv.FormatUint(d.dataset.Used, 10)},
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{"Space Available", strconv.FormatUint(d.dataset.Avail, 10)},
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{"Parent Quota", quota},
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{"Compression", d.dataset.Compression},
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}
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}
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func cloneFilesystem(id, parent, mountpoint string) error {
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parentDataset, err := zfs.GetDataset(parent)
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if parentDataset == nil {
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return err
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}
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snapshotName := fmt.Sprintf("%d", time.Now().Nanosecond())
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snapshot, err := parentDataset.Snapshot(snapshotName /*recursive */, false)
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if snapshot == nil {
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return err
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}
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_, err = snapshot.Clone(id, map[string]string{
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"mountpoint": mountpoint,
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})
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if err != nil {
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snapshot.Destroy(zfs.DestroyDeferDeletion)
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return err
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}
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err = snapshot.Destroy(zfs.DestroyDeferDeletion)
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return err
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}
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func (d *Driver) ZfsPath(id string) string {
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return d.options.fsName + "/" + id
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}
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func (d *Driver) Create(id string, parent string) error {
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mountPoint := path.Join(d.options.mountPath, "graph", id)
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datasetName := d.ZfsPath(id)
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dataset, err := zfs.GetDataset(datasetName)
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if err == nil {
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// cleanup existing dataset from an aborted build
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dataset.Destroy(zfs.DestroyRecursiveClones)
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}
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if parent == "" {
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_, err := zfs.CreateFilesystem(datasetName, map[string]string{
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"mountpoint": mountPoint,
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})
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return err
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} else {
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return cloneFilesystem(datasetName, d.ZfsPath(parent), mountPoint)
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}
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return nil
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}
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func (d *Driver) Remove(id string) error {
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dataset, err := zfs.GetDataset(d.ZfsPath(id))
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if dataset == nil {
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return err
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}
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return dataset.Destroy(zfs.DestroyRecursive)
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}
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func (d *Driver) Get(id, mountLabel string) (string, error) {
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dataset, err := zfs.GetDataset(d.ZfsPath(id))
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if dataset == nil {
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return "", err
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} else {
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return dataset.Mountpoint, nil
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}
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}
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func (d *Driver) Put(id string) error {
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// FS is already mounted
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return nil
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}
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func (d *Driver) Exists(id string) bool {
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_, err := zfs.GetDataset(d.ZfsPath(id))
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return err == nil
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}
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func zfsChanges(dataset *zfs.Dataset) ([]archive.Change, error) {
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if dataset.Origin == "" { // should never happen
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return nil, fmt.Errorf("no origin found for dataset '%s'. expected a clone", dataset.Name)
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}
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changes, err := dataset.Diff(dataset.Origin)
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if err != nil {
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return nil, err
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}
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// for rename changes, we have to add a ADD and a REMOVE
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renameCount := 0
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for _, change := range changes {
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if change.Change == zfs.Renamed {
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renameCount++
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}
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}
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archiveChanges := make([]archive.Change, len(changes)+renameCount)
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i := 0
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for _, change := range changes {
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var changeType archive.ChangeType
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mountpointLen := len(dataset.Mountpoint)
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basePath := change.Path[mountpointLen:]
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switch change.Change {
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case zfs.Renamed:
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archiveChanges[i] = archive.Change{basePath, archive.ChangeDelete}
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newBasePath := change.NewPath[mountpointLen:]
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archiveChanges[i+1] = archive.Change{newBasePath, archive.ChangeAdd}
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i += 2
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continue
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case zfs.Created:
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changeType = archive.ChangeAdd
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case zfs.Modified:
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changeType = archive.ChangeModify
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case zfs.Removed:
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changeType = archive.ChangeDelete
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}
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archiveChanges[i] = archive.Change{basePath, changeType}
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i++
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}
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return archiveChanges, nil
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}
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func (d *Driver) Diff(id, parent string) (archive.Archive, error) {
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dataset, err := zfs.GetDataset(d.ZfsPath(id))
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if err != nil {
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return nil, err
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}
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changes, err := zfsChanges(dataset)
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if err != nil {
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return nil, err
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}
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archive, err := archive.ExportChanges(dataset.Mountpoint, changes)
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if err != nil {
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return nil, err
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}
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return ioutils.NewReadCloserWrapper(archive, func() error {
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err := archive.Close()
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d.Put(id)
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return err
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}), nil
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}
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func (d *Driver) DiffSize(id, parent string) (bytes int64, err error) {
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dataset, err := zfs.GetDataset(d.ZfsPath(id))
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if err == nil {
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return int64((*dataset).Logicalused), nil
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} else {
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return -1, err
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}
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}
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func (d *Driver) Changes(id, parent string) ([]archive.Change, error) {
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dataset, err := zfs.GetDataset(d.ZfsPath(id))
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if err != nil {
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return nil, err
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}
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return zfsChanges(dataset)
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}
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func (d *Driver) ApplyDiff(id, parent string, diff archive.ArchiveReader) (int64, error) {
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dataset, err := zfs.GetDataset(d.ZfsPath(id))
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if err != nil {
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return -1, err
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}
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_, err = archive.ApplyLayer(dataset.Mountpoint, diff)
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if err != nil {
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return -1, err
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}
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updatedDataset, err := zfs.GetDataset(d.ZfsPath(id))
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if err != nil {
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return -1, err
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}
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return int64(updatedDataset.Logicalused), nil
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}
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