func (ZpoolTests) TestOrphanedZpoolFileAdoption(c *C) {
dataset := "testpool-bananagram"
backingFilePath := fmt.Sprintf("/tmp/zfs-%s", random.String(12))
defer os.Remove(backingFilePath)
provider, err := NewProvider(&ProviderConfig{
DatasetName: dataset,
Make: &MakeDev{
BackingFilename: backingFilePath,
Size: one_gig,
},
})
defer func() {
pool, _ := gzfs.GetZpool(dataset)
if pool != nil {
pool.Destroy()
}
}()
c.Assert(err, IsNil)
c.Assert(provider, NotNil)
// add a dataset to this zpool, so we can check for it on the flip side
markerDatasetName := path.Join(dataset, "testfs")
_, err = gzfs.CreateFilesystem(markerDatasetName, nil)
c.Assert(err, IsNil)
// do a 'zpool export'
// this roughly approximates what we see after a host reboot
// (though host reboots may leave it in an even more unclean state than this)
err = exec.Command("zpool", "export", "-f", dataset).Run()
c.Assert(err, IsNil)
// sanity check that our test is doing the right thing: zpool forgot about these
_, err = gzfs.GetDataset(dataset)
c.Assert(err, NotNil)
_, err = gzfs.GetDataset(markerDatasetName)
c.Assert(err, NotNil)
// if we create another provider with the same file vdev path, it should
// pick up that file again without wrecking the dataset
provider, err = NewProvider(&ProviderConfig{
DatasetName: dataset,
Make: &MakeDev{
BackingFilename: backingFilePath,
Size: one_gig,
},
})
c.Assert(err, IsNil)
c.Assert(provider, NotNil)
_, err = gzfs.GetDataset(markerDatasetName)
c.Assert(err, IsNil)
}
func (b *Provider) SendSnapshot(vol volume.Volume, haves []json.RawMessage, output io.Writer) error {
zvol, err := b.owns(vol)
if err != nil {
return err
}
if !vol.IsSnapshot() {
return fmt.Errorf("can only send a snapshot")
}
// zfs recv can only really accept snapshots that apply to the current tip
var latestRemote string
if haves != nil && len(haves) > 0 {
have := &zfsHaves{}
if err := json.Unmarshal(haves[len(haves)-1], have); err == nil {
latestRemote = have.SnapID
}
}
// look for intersection of existing snapshots on this volume; if so do incremental
parentName := strings.SplitN(zvol.dataset.Name, "@", 2)[0]
parentDataset, err := zfs.GetDataset(parentName)
if err != nil {
return err
}
snapshots, err := parentDataset.Snapshots()
if err != nil {
return err
}
// we can fly incremental iff the latest snap on the remote is available here
useIncremental := false
if latestRemote != "" {
for _, snap := range snapshots {
if strings.SplitN(snap.Name, "@", 2)[1] == latestRemote {
useIncremental = true
break
}
}
}
// at last, send:
if useIncremental {
sendCmd := exec.Command("zfs", "send", "-i", latestRemote, zvol.dataset.Name)
sendCmd.Stdout = output
return sendCmd.Run()
}
return zvol.dataset.SendSnapshot(output)
}
func (b *Provider) RestoreVolumeState(volInfo *volume.Info, data json.RawMessage) (volume.Volume, error) {
record := &zfsVolumeRecord{}
if err := json.Unmarshal(data, record); err != nil {
return nil, fmt.Errorf("cannot restore volume %q: %s", volInfo.ID, err)
}
dataset, err := zfs.GetDataset(record.Dataset)
if err != nil {
return nil, fmt.Errorf("cannot restore volume %q: %s", volInfo.ID, err)
}
v := &zfsVolume{
info: volInfo,
provider: b,
dataset: dataset,
basemount: record.Basemount,
}
if err := b.mountDataset(v); err != nil {
return nil, err
}
b.volumes[volInfo.ID] = v
return v, nil
}
func (b *Provider) RestoreVolumeState(volInfo *volume.Info, data json.RawMessage) (volume.Volume, error) {
record := &zfsVolumeRecord{}
if err := json.Unmarshal(data, record); err != nil {
return nil, fmt.Errorf("cannot restore volume %q: %s", volInfo.ID, err)
}
dataset, err := zfs.GetDataset(record.Dataset)
if err != nil {
return nil, fmt.Errorf("cannot restore volume %q: %s", volInfo.ID, err)
}
v := &zfsVolume{
info: volInfo,
provider: b,
dataset: dataset,
basemount: record.Basemount,
}
// zfs should have already remounted filesystems; special remount case for snapshots
if v.IsSnapshot() {
if err := b.mountSnapshot(v); err != nil {
return nil, err
}
}
b.volumes[volInfo.ID] = v
return v, nil
}
func NewProvider(config *ProviderConfig) (volume.Provider, error) {
if _, err := exec.LookPath("zfs"); err != nil {
return nil, fmt.Errorf("zfs command is not available")
}
dataset, err := zfs.GetDataset(config.DatasetName)
if err != nil {
if isDatasetNotExistsError(err) {
// if the dataset doesn't exist...
if config.Make == nil {
// not much we can do without a dataset or pool to contain data
return nil, err
}
// make a zpool backed by a sparse file. it's the most portable thing we can do.
if err := os.MkdirAll(filepath.Dir(config.Make.BackingFilename), 0755); err != nil {
return nil, err
}
f, err := os.OpenFile(config.Make.BackingFilename, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0600)
if err == nil {
// if we've created a new file, size it and create a new zpool
if err = f.Truncate(config.Make.Size); err != nil {
return nil, err
}
f.Close()
if _, err = zfs.CreateZpool(
config.DatasetName,
nil,
"-mnone", // do not mount the root dataset. (we'll mount our own datasets as necessary.)
config.Make.BackingFilename,
); err != nil {
return nil, err
}
} else if err.(*os.PathError).Err == syscall.EEXIST {
// if the file already exists, check it for existing zpool
if err := zpoolImportFile(config.Make.BackingFilename); err != nil {
// if 'zpool import' didn't believe it... halt here
// we could overwrite but we'd rather stop and avoid potential data loss.
return nil, fmt.Errorf("error attempting import of existing zpool file: %s", err)
}
// note: 'zpool import' recreated *all* the volume datasets in that pool.
// currently, even if they're not known to a volume manager, they're not garbage collected.
} else {
return nil, err
}
// get the dataset again... `zfs.Zpool` isn't a `zfs.Dataset`
dataset, err = zfs.GetDataset(config.DatasetName)
if err != nil {
return nil, err
}
} else {
// any error more complicated than not_exists, and we're out of our depth
return nil, err
}
}
if config.WorkingDir == "" {
config.WorkingDir = "/var/lib/flynn/volumes/zfs/"
}
return &Provider{
config: config,
dataset: dataset,
volumes: make(map[string]*zfsVolume),
}, nil
}