rbd: introduce rbdImage as base for rbdVolume and rbdSnapshot

Because rbdVolume and rbdSnapshot are very similar, they can be based off a common struct rbdImage that contains the common attributes and functions. This makes it possible to re-use functions for snapshots, and prevents further duplication or code. Signed-off-by: Niels de Vos <ndevos@redhat.com>
2024-12-23 21:40:20 +00:00 · 2021-03-12 13:37:15 +01:00 · 2021-03-12 13:37:15 +01:00 · 10a75dd4ff
commit 10a75dd4ff
parent 3fe714c4fa
4 changed files with 171 additions and 167 deletions
--- a/internal/rbd/clone.go
+++ b/internal/rbd/clone.go
@ -46,10 +46,10 @@ import (
 func (rv *rbdVolume) checkCloneImage(ctx context.Context, parentVol *rbdVolume) (bool, error) {
 	// generate temp cloned volume
 	tempClone := rv.generateTempClone()
-	snap := &rbdSnapshot{
-		RbdSnapName: rv.RbdImageName,
-		Pool:        rv.Pool,
-	}
+	snap := &rbdSnapshot{}
+	snap.RbdSnapName = rv.RbdImageName
+	snap.Pool = rv.Pool
+
 	// check if cloned image exists
 	err := rv.getImageInfo()
 	if err == nil {
@ -145,18 +145,17 @@ func (rv *rbdVolume) generateTempClone() *rbdVolume {
 func (rv *rbdVolume) createCloneFromImage(ctx context.Context, parentVol *rbdVolume) error {
 	// generate temp cloned volume
 	tempClone := rv.generateTempClone()
-	tempSnap := &rbdSnapshot{
-		// snapshot name is same as temporary cloned image, This helps to
-		// flatten the temporary cloned images as we cannot have more than 510
-		// snapshots on an rbd image
-		RbdSnapName: tempClone.RbdImageName,
-		Pool:        rv.Pool,
-	}
+	// snapshot name is same as temporary cloned image, This helps to
+	// flatten the temporary cloned images as we cannot have more than 510
+	// snapshots on an rbd image
+	tempSnap := &rbdSnapshot{}
+	tempSnap.RbdSnapName = tempClone.RbdImageName
+	tempSnap.Pool = rv.Pool
+
+	cloneSnap := &rbdSnapshot{}
+	cloneSnap.RbdSnapName = rv.RbdImageName
+	cloneSnap.Pool = rv.Pool

-	cloneSnap := &rbdSnapshot{
-		RbdSnapName: rv.RbdImageName,
-		Pool:        rv.Pool,
-	}
 	var (
 		errClone   error
 		errFlatten error
--- a/internal/rbd/encryption.go
+++ b/internal/rbd/encryption.go
@ -61,71 +61,71 @@ const (
 )

 // checkRbdImageEncrypted verifies if rbd image was encrypted when created.
-func (rv *rbdVolume) checkRbdImageEncrypted(ctx context.Context) (rbdEncryptionState, error) {
-	value, err := rv.GetMetadata(encryptionMetaKey)
+func (ri *rbdImage) checkRbdImageEncrypted(ctx context.Context) (rbdEncryptionState, error) {
+	value, err := ri.GetMetadata(encryptionMetaKey)
 	if errors.Is(err, librbd.ErrNotFound) {
-		util.DebugLog(ctx, "image %s encrypted state not set", rv.String())
+		util.DebugLog(ctx, "image %s encrypted state not set", ri.String())
 		return rbdImageEncryptionUnknown, nil
 	} else if err != nil {
-		util.ErrorLog(ctx, "checking image %s encrypted state metadata failed: %s", rv.String(), err)
+		util.ErrorLog(ctx, "checking image %s encrypted state metadata failed: %s", ri.String(), err)
 		return rbdImageEncryptionUnknown, err
 	}

 	encrypted := rbdEncryptionState(strings.TrimSpace(value))
-	util.DebugLog(ctx, "image %s encrypted state metadata reports %q", rv.String(), encrypted)
+	util.DebugLog(ctx, "image %s encrypted state metadata reports %q", ri.String(), encrypted)
 	return encrypted, nil
 }

-func (rv *rbdVolume) ensureEncryptionMetadataSet(status rbdEncryptionState) error {
-	err := rv.SetMetadata(encryptionMetaKey, string(status))
+func (ri *rbdImage) ensureEncryptionMetadataSet(status rbdEncryptionState) error {
+	err := ri.SetMetadata(encryptionMetaKey, string(status))
 	if err != nil {
-		return fmt.Errorf("failed to save encryption status for %s: %w", rv, err)
+		return fmt.Errorf("failed to save encryption status for %s: %w", ri, err)
 	}

 	return nil
 }

-// isEncrypted returns `true` if the rbdVolume is (or needs to be) encrypted.
-func (rv *rbdVolume) isEncrypted() bool {
-	return rv.encryption != nil
+// isEncrypted returns `true` if the rbdImage is (or needs to be) encrypted.
+func (ri *rbdImage) isEncrypted() bool {
+	return ri.encryption != nil
 }

 // setupEncryption configures the metadata of the RBD image for encryption:
 // - the Data-Encryption-Key (DEK) will be generated stored for use by the KMS;
 // - the RBD image will be marked to support encryption in its metadata.
-func (rv *rbdVolume) setupEncryption(ctx context.Context) error {
-	err := rv.encryption.StoreNewCryptoPassphrase(rv.VolID)
+func (ri *rbdImage) setupEncryption(ctx context.Context) error {
+	err := ri.encryption.StoreNewCryptoPassphrase(ri.VolID)
 	if err != nil {
 		util.ErrorLog(ctx, "failed to save encryption passphrase for "+
-			"image %s: %s", rv.String(), err)
+			"image %s: %s", ri.String(), err)
 		return err
 	}

-	err = rv.ensureEncryptionMetadataSet(rbdImageEncryptionPrepared)
+	err = ri.ensureEncryptionMetadataSet(rbdImageEncryptionPrepared)
 	if err != nil {
 		util.ErrorLog(ctx, "failed to save encryption status, deleting "+
-			"image %s: %s", rv.String(), err)
+			"image %s: %s", ri.String(), err)
 		return err
 	}

 	return nil
 }

-func (rv *rbdVolume) encryptDevice(ctx context.Context, devicePath string) error {
-	passphrase, err := rv.encryption.GetCryptoPassphrase(rv.VolID)
+func (ri *rbdImage) encryptDevice(ctx context.Context, devicePath string) error {
+	passphrase, err := ri.encryption.GetCryptoPassphrase(ri.VolID)
 	if err != nil {
 		util.ErrorLog(ctx, "failed to get crypto passphrase for %s: %v",
-			rv.String(), err)
+			ri.String(), err)
 		return err
 	}

 	if err = util.EncryptVolume(ctx, devicePath, passphrase); err != nil {
-		err = fmt.Errorf("failed to encrypt volume %s: %w", rv.String(), err)
+		err = fmt.Errorf("failed to encrypt volume %s: %w", ri.String(), err)
 		util.ErrorLog(ctx, err.Error())
 		return err
 	}

-	err = rv.ensureEncryptionMetadataSet(rbdImageEncrypted)
+	err = ri.ensureEncryptionMetadataSet(rbdImageEncrypted)
 	if err != nil {
 		util.ErrorLog(ctx, err.Error())
 		return err
@ -163,7 +163,7 @@ func (rv *rbdVolume) openEncryptedDevice(ctx context.Context, devicePath string)
 	return mapperFilePath, nil
 }

-func (rv *rbdVolume) initKMS(ctx context.Context, volOptions, credentials map[string]string) error {
+func (ri *rbdImage) initKMS(ctx context.Context, volOptions, credentials map[string]string) error {
 	var (
 		err       error
 		ok        bool
@ -174,9 +174,9 @@ func (rv *rbdVolume) initKMS(ctx context.Context, volOptions, credentials map[st
 	// depending on the tenant, the KMS can be configured with other
 	// options
 	// FIXME: this works only on Kubernetes, how do other CO supply metadata?
-	rv.Owner, ok = volOptions["csi.storage.k8s.io/pvc/namespace"]
+	ri.Owner, ok = volOptions["csi.storage.k8s.io/pvc/namespace"]
 	if !ok {
-		util.DebugLog(ctx, "could not detect owner for %s", rv.String())
+		util.DebugLog(ctx, "could not detect owner for %s", ri.String())
 	}

 	encrypted, ok = volOptions["encrypted"]
@ -192,7 +192,7 @@ func (rv *rbdVolume) initKMS(ctx context.Context, volOptions, credentials map[st
 		return nil
 	}

-	err = rv.configureEncryption(volOptions["encryptionKMSID"], credentials)
+	err = ri.configureEncryption(volOptions["encryptionKMSID"], credentials)
 	if err != nil {
 		return fmt.Errorf("invalid encryption kms configuration: %w", err)
 	}
@ -200,48 +200,48 @@ func (rv *rbdVolume) initKMS(ctx context.Context, volOptions, credentials map[st
 	return nil
 }

-// configureEncryption sets up the VolumeEncryption for this rbdVolume. Once
+// configureEncryption sets up the VolumeEncryption for this rbdImage. Once
 // configured, use isEncrypted() to see if the volume supports encryption.
-func (rv *rbdVolume) configureEncryption(kmsID string, credentials map[string]string) error {
-	kms, err := util.GetKMS(rv.Owner, kmsID, credentials)
+func (ri *rbdImage) configureEncryption(kmsID string, credentials map[string]string) error {
+	kms, err := util.GetKMS(ri.Owner, kmsID, credentials)
 	if err != nil {
 		return err
 	}

-	rv.encryption, err = util.NewVolumeEncryption(kms)
+	ri.encryption, err = util.NewVolumeEncryption(kms)

 	// if the KMS can not store the DEK itself, we'll store it in the
 	// metadata of the RBD image itself
 	if errors.Is(err, util.ErrDEKStoreNeeded) {
-		rv.encryption.SetDEKStore(rv)
+		ri.encryption.SetDEKStore(ri)
 	}

 	return nil
 }

 // StoreDEK saves the DEK in the metadata, overwrites any existing contents.
-func (rv *rbdVolume) StoreDEK(volumeID, dek string) error {
-	if rv.VolID != volumeID {
-		return fmt.Errorf("volume %q can not store DEK for %q", rv.String(), volumeID)
+func (ri *rbdImage) StoreDEK(volumeID, dek string) error {
+	if ri.VolID != volumeID {
+		return fmt.Errorf("volume %q can not store DEK for %q", ri.String(), volumeID)
 	}

-	return rv.SetMetadata(metadataDEK, dek)
+	return ri.SetMetadata(metadataDEK, dek)
 }

 // FetchDEK reads the DEK from the image metadata.
-func (rv *rbdVolume) FetchDEK(volumeID string) (string, error) {
-	if rv.VolID != volumeID {
-		return "", fmt.Errorf("volume %q can not fetch DEK for %q", rv.String(), volumeID)
+func (ri *rbdImage) FetchDEK(volumeID string) (string, error) {
+	if ri.VolID != volumeID {
+		return "", fmt.Errorf("volume %q can not fetch DEK for %q", ri.String(), volumeID)
 	}

-	return rv.GetMetadata(metadataDEK)
+	return ri.GetMetadata(metadataDEK)
 }

 // RemoveDEK does not need to remove the DEK from the metadata, the image is
 // most likely getting removed.
-func (rv *rbdVolume) RemoveDEK(volumeID string) error {
-	if rv.VolID != volumeID {
-		return fmt.Errorf("volume %q can not remove DEK for %q", rv.String(), volumeID)
+func (ri *rbdImage) RemoveDEK(volumeID string) error {
+	if ri.VolID != volumeID {
+		return fmt.Errorf("volume %q can not remove DEK for %q", ri.String(), volumeID)
 	}

 	return nil
--- a/internal/rbd/rbd_journal.go
+++ b/internal/rbd/rbd_journal.go
@ -491,7 +491,8 @@ func RegenerateJournal(imageName, volumeID, pool, journalPool, requestName strin
 	)

 	options = make(map[string]string)
-	rbdVol = &rbdVolume{VolID: volumeID}
+	rbdVol = &rbdVolume{}
+	rbdVol.VolID = volumeID

 	err := vi.DecomposeCSIID(rbdVol.VolID)
 	if err != nil {
--- a/internal/rbd/rbd_util.go
+++ b/internal/rbd/rbd_util.go
@ -58,84 +58,88 @@ const (
 	thickProvisionMetaKey = ".rbd.csi.ceph.com/thick-provisioned"
 )

-// rbdVolume represents a CSI volume and its RBD image specifics.
-type rbdVolume struct {
-	// RbdImageName is the name of the RBD image backing this rbdVolume. This does not have a
-	//   JSON tag as it is not stashed in JSON encoded config maps in v1.0.0
-	// VolID is the volume ID that is exchanged with CSI drivers, identifying this rbdVol
-	// RequestName is the CSI generated volume name for the rbdVolume.  This does not have a
-	//   JSON tag as it is not stashed in JSON encoded config maps in v1.0.0
-	// VolName and MonValueFromSecret are retained from older plugin versions (<= 1.0.0)
-	//   for backward compatibility reasons
-	// JournalPool is the ceph pool in which the CSI Journal is stored
-	// Pool is where the image journal and image is stored, and could be the same as `JournalPool`
-	//   (retained as Pool instead of renaming to ImagePool or such, as this is referenced in the code extensively)
-	// DataPool is where the data for images in `Pool` are stored, this is used as the `--data-pool`
-	// 	 argument when the pool is created, and is not used anywhere else
-	TopologyPools       *[]util.TopologyConstrainedPool
-	TopologyRequirement *csi.TopologyRequirement
-	Topology            map[string]string
-	RbdImageName        string
-	NamePrefix          string
-	VolID               string `json:"volID"`
-	Monitors            string `json:"monitors"`
-	JournalPool         string
-	Pool                string `json:"pool"`
-	DataPool            string
-	RadosNamespace      string
-	ImageID             string
-	ParentName          string
-	imageFeatureSet     librbd.FeatureSet
-	AdminID             string `json:"adminId"`
-	UserID              string `json:"userId"`
-	Mounter             string `json:"mounter"`
-	ClusterID           string `json:"clusterId"`
-	RequestName         string
-	ReservedID          string
-	MapOptions          string
-	UnmapOptions        string
-	VolName             string `json:"volName"`
-	MonValueFromSecret  string `json:"monValueFromSecret"`
-	VolSize             int64  `json:"volSize"`
-	DisableInUseChecks  bool   `json:"disableInUseChecks"`
-	readOnly            bool
-	Primary             bool
-	ThickProvision      bool
-	encryption          *util.VolumeEncryption
-	// Owner is the creator (tenant, Kubernetes Namespace) of the volume.
-	Owner     string
+// rbdImage contains common attributes and methods for the rbdVolume and
+// rbdSnapshot types.
+type rbdImage struct {
+	// RbdImageName is the name of the RBD image backing this rbdVolume.
+	// This does not have a JSON tag as it is not stashed in JSON encoded
+	// config maps in v1.0.0
+	RbdImageName string
+	// ImageID contains the image id of the image
+	ImageID string
+	// VolID is the volume ID that is exchanged with CSI drivers,
+	// identifying this rbd image
+	VolID string `json:"volID"`
+
+	Monitors string
+	// JournalPool is the ceph pool in which the CSI snapshot Journal is
+	// stored
+	JournalPool string
+	// Pool is where the image snapshot journal and snapshot is stored, and
+	// could be the same as `JournalPool` (retained as Pool instead of
+	// renaming to ImagePool or such, as this is referenced in the code
+	// extensively)
+	Pool           string
+	RadosNamespace string
+	ClusterID      string `json:"clusterId"`
+	// RequestName is the CSI generated volume name for the rbdVolume.
+	// This does not have a JSON tag as it is not stashed in JSON encoded
+	// config maps in v1.0.0
+	RequestName string
+	NamePrefix  string
+
+	// encryption provides access to optional VolumeEncryption functions
+	encryption *util.VolumeEncryption
+	// Owner is the creator (tenant, Kubernetes Namespace) of the volume
+	Owner string
+
 	CreatedAt *timestamp.Timestamp
+
 	// conn is a connection to the Ceph cluster obtained from a ConnPool
 	conn *util.ClusterConnection
 	// an opened IOContext, call .openIoctx() before using
 	ioctx *rados.IOContext
 }

+// rbdVolume represents a CSI volume and its RBD image specifics.
+type rbdVolume struct {
+	rbdImage
+
+	// VolName and MonValueFromSecret are retained from older plugin versions (<= 1.0.0)
+	//   for backward compatibility reasons
+	TopologyPools       *[]util.TopologyConstrainedPool
+	TopologyRequirement *csi.TopologyRequirement
+	Topology            map[string]string
+	// DataPool is where the data for images in `Pool` are stored, this is used as the `--data-pool`
+	// 	 argument when the pool is created, and is not used anywhere else
+	DataPool           string
+	ParentName         string
+	imageFeatureSet    librbd.FeatureSet
+	AdminID            string `json:"adminId"`
+	UserID             string `json:"userId"`
+	Mounter            string `json:"mounter"`
+	ReservedID         string
+	MapOptions         string
+	UnmapOptions       string
+	VolName            string `json:"volName"`
+	MonValueFromSecret string `json:"monValueFromSecret"`
+	VolSize            int64  `json:"volSize"`
+	DisableInUseChecks bool   `json:"disableInUseChecks"`
+	readOnly           bool
+	Primary            bool
+	ThickProvision     bool
+}
+
 // rbdSnapshot represents a CSI snapshot and its RBD snapshot specifics.
 type rbdSnapshot struct {
+	rbdImage
+
 	// SourceVolumeID is the volume ID of RbdImageName, that is exchanged with CSI drivers
-	// RbdImageName is the name of the RBD image, that is this rbdSnapshot's source image
 	// RbdSnapName is the name of the RBD snapshot backing this rbdSnapshot
-	// VolID is the snapshot ID that is exchanged with CSI drivers, identifying this rbdSnapshot
-	// RequestName is the CSI generated snapshot name for the rbdSnapshot
-	// JournalPool is the ceph pool in which the CSI snapshot Journal is stored
-	// Pool is where the image snapshot journal and snapshot is stored, and could be the same as `JournalPool`
-	// ImageID contains the image id of cloned image
 	SourceVolumeID string
-	RbdImageName   string
 	ReservedID     string
-	NamePrefix     string
 	RbdSnapName    string
-	VolID          string
-	ImageID        string
-	Monitors       string
-	JournalPool    string
-	Pool           string
-	RadosNamespace string
-	CreatedAt      *timestamp.Timestamp
 	SizeBytes      int64
-	ClusterID      string
-	RequestName    string
 }

 var (
@ -143,40 +147,40 @@ var (
 )

 // Connect an rbdVolume to the Ceph cluster.
-func (rv *rbdVolume) Connect(cr *util.Credentials) error {
-	if rv.conn != nil {
+func (ri *rbdImage) Connect(cr *util.Credentials) error {
+	if ri.conn != nil {
 		return nil
 	}

 	conn := &util.ClusterConnection{}
-	if err := conn.Connect(rv.Monitors, cr); err != nil {
+	if err := conn.Connect(ri.Monitors, cr); err != nil {
 		return err
 	}

-	rv.conn = conn
+	ri.conn = conn
 	return nil
 }

 // Destroy cleans up the rbdVolume and closes the connection to the Ceph
 // cluster in case one was setup.
-func (rv *rbdVolume) Destroy() {
-	if rv.ioctx != nil {
-		rv.ioctx.Destroy()
+func (ri *rbdImage) Destroy() {
+	if ri.ioctx != nil {
+		ri.ioctx.Destroy()
 	}
-	if rv.conn != nil {
-		rv.conn.Destroy()
+	if ri.conn != nil {
+		ri.conn.Destroy()
 	}
-	if rv.isEncrypted() {
-		rv.encryption.Destroy()
+	if ri.isEncrypted() {
+		ri.encryption.Destroy()
 	}
 }

 // String returns the image-spec (pool/{namespace/}image) format of the image.
-func (rv *rbdVolume) String() string {
-	if rv.RadosNamespace != "" {
-		return fmt.Sprintf("%s/%s/%s", rv.Pool, rv.RadosNamespace, rv.RbdImageName)
+func (ri *rbdImage) String() string {
+	if ri.RadosNamespace != "" {
+		return fmt.Sprintf("%s/%s/%s", ri.Pool, ri.RadosNamespace, ri.RbdImageName)
 	}
-	return fmt.Sprintf("%s/%s", rv.Pool, rv.RbdImageName)
+	return fmt.Sprintf("%s/%s", ri.Pool, ri.RbdImageName)
 }

 // String returns the snap-spec (pool/{namespace/}image@snap) format of the snapshot.
@ -247,19 +251,19 @@ func createImage(ctx context.Context, pOpts *rbdVolume, cr *util.Credentials) er
 	return nil
 }

-func (rv *rbdVolume) openIoctx() error {
-	if rv.ioctx != nil {
+func (ri *rbdImage) openIoctx() error {
+	if ri.ioctx != nil {
 		return nil
 	}

-	ioctx, err := rv.conn.GetIoctx(rv.Pool)
+	ioctx, err := ri.conn.GetIoctx(ri.Pool)
 	if err != nil {
 		// GetIoctx() can return util.ErrPoolNotFound
 		return err
 	}

-	ioctx.SetNamespace(rv.RadosNamespace)
-	rv.ioctx = ioctx
+	ioctx.SetNamespace(ri.RadosNamespace)
+	ri.ioctx = ioctx

 	return nil
 }
@ -284,17 +288,17 @@ func (rv *rbdVolume) getImageID() error {
 	return nil
 }

-// open the rbdVolume after it has been connected.
+// open the rbdImage after it has been connected.
 // ErrPoolNotFound or ErrImageNotFound are returned in case the pool or image
 // can not be found, other errors will contain more details about other issues
 // (permission denied, ...) and are expected to relate to configuration issues.
-func (rv *rbdVolume) open() (*librbd.Image, error) {
-	err := rv.openIoctx()
+func (ri *rbdImage) open() (*librbd.Image, error) {
+	err := ri.openIoctx()
 	if err != nil {
 		return nil, err
 	}

-	image, err := librbd.OpenImage(rv.ioctx, rv.RbdImageName, librbd.NoSnapshot)
+	image, err := librbd.OpenImage(ri.ioctx, ri.RbdImageName, librbd.NoSnapshot)
 	if err != nil {
 		if errors.Is(err, librbd.ErrNotFound) {
 			err = util.JoinErrors(ErrImageNotFound, err)
@ -488,12 +492,11 @@ func deleteImage(ctx context.Context, pOpts *rbdVolume, cr *util.Credentials) er

 func (rv *rbdVolume) getCloneDepth(ctx context.Context) (uint, error) {
 	var depth uint
-	vol := rbdVolume{
-		Pool:         rv.Pool,
-		Monitors:     rv.Monitors,
-		RbdImageName: rv.RbdImageName,
-		conn:         rv.conn,
-	}
+	vol := rbdVolume{}
+	vol.Pool = rv.Pool
+	vol.Monitors = rv.Monitors
+	vol.RbdImageName = rv.RbdImageName
+	vol.conn = rv.conn

 	err := vol.openIoctx()
 	if err != nil {
@ -530,11 +533,11 @@ type trashSnapInfo struct {
 }

 func flattenClonedRbdImages(ctx context.Context, snaps []librbd.SnapInfo, pool, monitors, rbdImageName string, cr *util.Credentials) error {
-	rv := &rbdVolume{
-		Monitors:     monitors,
-		Pool:         pool,
-		RbdImageName: rbdImageName,
-	}
+	rv := &rbdVolume{}
+	rv.Monitors = monitors
+	rv.Pool = pool
+	rv.RbdImageName = rbdImageName
+
 	defer rv.Destroy()
 	err := rv.Connect(cr)
 	if err != nil {
@ -658,13 +661,13 @@ func (rv *rbdVolume) hasFeature(feature uint64) bool {
 }

 func (rv *rbdVolume) checkImageChainHasFeature(ctx context.Context, feature uint64) (bool, error) {
-	vol := rbdVolume{
-		Pool:           rv.Pool,
-		RadosNamespace: rv.RadosNamespace,
-		Monitors:       rv.Monitors,
-		RbdImageName:   rv.RbdImageName,
-		conn:           rv.conn,
-	}
+	vol := rbdVolume{}
+	vol.Pool = rv.Pool
+	vol.RadosNamespace = rv.RadosNamespace
+	vol.Monitors = rv.Monitors
+	vol.RbdImageName = rv.RbdImageName
+	vol.conn = rv.conn
+
 	err := vol.openIoctx()
 	if err != nil {
 		return false, err
@ -765,7 +768,8 @@ func genVolFromVolID(ctx context.Context, volumeID string, cr *util.Credentials,

 	// rbdVolume fields that are not filled up in this function are:
 	//              Mounter, MultiNodeWritable
-	rbdVol = &rbdVolume{VolID: volumeID}
+	rbdVol = &rbdVolume{}
+	rbdVol.VolID = volumeID

 	err = vi.DecomposeCSIID(rbdVol.VolID)
 	if err != nil {
@ -1269,8 +1273,8 @@ func (rv *rbdVolume) resize(newSize int64) error {
 	return nil
 }

-func (rv *rbdVolume) GetMetadata(key string) (string, error) {
-	image, err := rv.open()
+func (ri *rbdImage) GetMetadata(key string) (string, error) {
+	image, err := ri.open()
 	if err != nil {
 		return "", err
 	}
@ -1279,8 +1283,8 @@ func (rv *rbdVolume) GetMetadata(key string) (string, error) {
 	return image.GetMetadata(key)
 }

-func (rv *rbdVolume) SetMetadata(key, value string) error {
-	image, err := rv.open()
+func (ri *rbdImage) SetMetadata(key, value string) error {
+	image, err := ri.open()
 	if err != nil {
 		return err
 	}