fix(controller): prevent zfs volume cr deletion if snapshot exists

pkg/builder/volbuilder/build.go

@@ -21,6 +21,9 @@ import (
 	apis "github.com/openebs/zfs-localpv/pkg/apis/openebs.io/zfs/v1"
 )
 
+// MarkForDeletionAnnotation is the annotation key
+const MarkForDeletionAnnotation string = "openebs.io/marked-for-deletion"
+
 // Builder is the builder object for ZFSVolume
 type Builder struct {
 	volume *ZFSVolume
@@ -154,6 +157,15 @@ func (b *Builder) WithVolBlockSize(bs string) *Builder {
 	return b
 }
 
+// WithAnnotation sets the annotation of ZFSVolume
+func (b *Builder) WithAnnotation() *Builder {
+	if b.volume.Object.Annotations == nil {
+		b.volume.Object.Annotations = make(map[string]string)
+	}
+	b.volume.Object.Annotations[MarkForDeletionAnnotation] = "true"
+	return b
+}
+
 // WithVolumeType sets if ZFSVolume needs to be thin provisioned
 func (b *Builder) WithVolumeType(vtype string) *Builder {
 	b.volume.Object.Spec.VolumeType = vtype

pkg/driver/controller.go

@@ -503,14 +503,14 @@ func (cs *controller) DeleteVolume(
 	defer unlock()
 
 	// verify if the volume has already been deleted
-	vol, err := zfs.GetVolume(volumeID)
+	vol, err := zfs.GetZFSVolume(volumeID)
 	if vol != nil && vol.DeletionTimestamp != nil {
-		goto deleteResponse
+		return csipayload.NewDeleteVolumeResponseBuilder().Build(), nil
 	}
 
 	if err != nil {
 		if k8serror.IsNotFound(err) {
-			goto deleteResponse
+			return csipayload.NewDeleteVolumeResponseBuilder().Build(), nil
 		}
 		return nil, errors.Wrapf(
 			err,
@@ -524,19 +524,45 @@ func (cs *controller) DeleteVolume(
 		return nil, status.Error(codes.Internal, "can not delete, volume creation is in progress")
 	}
 
-	// Delete the corresponding ZV CR
-	err = zfs.DeleteVolume(volumeID)
+	// Fetch the list of snapshot for the given volume
+	snapList, err := zfs.GetSnapshotForVolume(volumeID)
 	if err != nil {
-		return nil, errors.Wrapf(
-			err,
-			"failed to handle delete volume request for {%s}",
-			volumeID,
+		return nil, status.Errorf(
+			codes.NotFound,
+			"failed to handle delete volume request for {%s}, "+
+				"validation failed checking for snapshots. Error: %s",
+			req.VolumeId,
+			err.Error(),
 		)
 	}
 
+	// Delete the corresponding ZV CR only if there are no snapshots present for the volume
+	if len(snapList.Items) == 0 {
+		err = zfs.DeleteVolume(volumeID)
+		if err != nil {
+			return nil, errors.Wrapf(
+				err,
+				"failed to handle delete volume request for {%s}",
+				volumeID,
+			)
+		}
+	} else {
+		// add annotation to the volume to indicate that it is eligible for deletion
+		// once all the snapshots are deleted and the reclaim policy is not Retain
+		// this volume will be deleted
+		err = zfs.MarkForDeletion(volumeID)
+		if err != nil {
+			return nil, errors.Wrapf(
+				err,
+				"failed to annotate volume on deletion request for {%s}",
+				volumeID,
+			)
+		}
+
+	}
+
 	sendEventOrIgnore("", volumeID, vol.Spec.Capacity, analytics.VolumeDeprovision)
 
-deleteResponse:
 	return csipayload.NewDeleteVolumeResponseBuilder().Build(), nil
 }
 
@@ -815,8 +841,36 @@ func (cs *controller) DeleteSnapshot(
 		// should succeed when an invalid snapshot id is used
 		return &csi.DeleteSnapshotResponse{}, nil
 	}
+	volumeID := snapshotID[0]
 	unlock := cs.volumeLock.LockVolumeWithSnapshot(snapshotID[0], snapshotID[1])
 	defer unlock()
+
+	// verify if the snapshot has already been deleted
+	_, err := zfs.GetZFSSnapshot(snapshotID[1])
+
+	if err != nil {
+		if k8serror.IsNotFound(err) {
+			return csipayload.NewDeleteSnapshotResponseBuilder().Build(), nil
+		}
+		return nil, errors.Wrapf(
+			err,
+			"failed to get snapshot for {%s}",
+			snapshotID[1],
+		)
+	}
+
+	// Fetch the list of snapshot for the given volume
+	snapList, err := zfs.GetSnapshotForVolume(volumeID)
+	if err != nil {
+		return nil, status.Errorf(
+			codes.FailedPrecondition,
+			"failed to handle delete snapshot request for {%s}, "+
+				"validation failed checking for snapshot list for volume. Error: %s",
+			volumeID,
+			err.Error(),
+		)
+	}
+
 	if err := zfs.DeleteSnapshot(snapshotID[1]); err != nil {
 		return nil, status.Errorf(
 			codes.Internal,
@@ -825,7 +879,34 @@ func (cs *controller) DeleteSnapshot(
 			err.Error(),
 		)
 	}
-	return &csi.DeleteSnapshotResponse{}, nil
+
+	eligibleForDeletion, err := zfs.IsVolumeEligibleForDeletion(volumeID)
+	if err != nil {
+		return nil, status.Errorf(
+			codes.FailedPrecondition,
+			"failed to handle delete snapshot request for {%s}, "+
+				"validation failed checking for eligible for deletion. Error: %s",
+			volumeID,
+			err.Error(),
+		)
+	}
+
+	klog.Infof(" The snap list size %v and eligibleForDeletion %v", len(snapList.Items), eligibleForDeletion)
+	// Delete the corresponding ZV CR only if this is the last snapshot
+	// for the volume and the corresponding pvc is deleted
+	if len(snapList.Items) == 1 && eligibleForDeletion {
+		err = zfs.DeleteVolume(volumeID)
+		if err != nil {
+			return nil, errors.Wrapf(
+				err,
+				"failed to handle delete volume request for {%s}",
+				volumeID,
+			)
+		}
+		klog.Infof("volume %s deleted after the deletion of last snapshot %s ", volumeID, snapshotID[1])
+	}
+
+	return csipayload.NewDeleteSnapshotResponseBuilder().Build(), nil
 }
 
 // ListSnapshots lists all snapshots for the

pkg/response/delete.go

@@ -39,3 +39,23 @@ func NewDeleteVolumeResponseBuilder() *DeleteVolumeResponseBuilder {
 func (b *DeleteVolumeResponseBuilder) Build() *csi.DeleteVolumeResponse {
 	return b.response
 }
+
+// DeleteSnapshotResponseBuilder helps building an
+// instance of csi DeleteSnapshotResponse
+type DeleteSnapshotResponseBuilder struct {
+	response *csi.DeleteSnapshotResponse
+}
+
+// NewDeleteSnapshotResponseBuilder returns a new
+// instance of DeleteSnapshotResponseBuilder
+func NewDeleteSnapshotResponseBuilder() *DeleteSnapshotResponseBuilder {
+	return &DeleteSnapshotResponseBuilder{
+		response: &csi.DeleteSnapshotResponse{},
+	}
+}
+
+// Build returns the constructed instance
+// of csi DeleteSnapshotResponse
+func (b *DeleteSnapshotResponseBuilder) Build() *csi.DeleteSnapshotResponse {
+	return b.response
+}

pkg/zfs/volume.go

@@ -27,6 +27,8 @@ import (
 	"github.com/openebs/zfs-localpv/pkg/builder/restorebuilder"
 	"github.com/openebs/zfs-localpv/pkg/builder/snapbuilder"
 	"github.com/openebs/zfs-localpv/pkg/builder/volbuilder"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/klog/v2"
 )
@@ -213,13 +215,6 @@ func DeleteSnapshot(snapname string) (err error) {
 	return
 }
 
-// GetVolume the corresponding ZFSVolume CR
-func GetVolume(volumeID string) (*apis.ZFSVolume, error) {
-	return volbuilder.NewKubeclient().
-		WithNamespace(OpenEBSNamespace).
-		Get(volumeID, metav1.GetOptions{})
-}
-
 // DeleteVolume deletes the corresponding ZFSVol CR
 func DeleteVolume(volumeID string) (err error) {
 	err = volbuilder.NewKubeclient().WithNamespace(OpenEBSNamespace).Delete(volumeID)
@@ -251,6 +246,18 @@ func GetZFSVolume(volumeID string) (*apis.ZFSVolume, error) {
 	return vol, err
 }
 
+// UpdateZFSVolumeAnnotation updtates the ZFSVolume CR with the given annotation
+func UpdateZFSVolumeAnnotation(vol *apis.ZFSVolume) error {
+	newVol, err := volbuilder.BuildFrom(vol).
+		WithAnnotation().Build()
+
+	if err != nil {
+		return err
+	}
+	_, err = volbuilder.NewKubeclient().WithNamespace(OpenEBSNamespace).Update(newVol)
+	return err
+}
+
 // GetZFSVolumeState returns ZFSVolume OwnerNode and State for
 // the given volume. CreateVolume request may call it again and
 // again until volume is "Ready".
@@ -441,3 +448,46 @@ func IsVolumeReady(vol *apis.ZFSVolume) bool {
 
 	return false
 }
+
+// GetSnapshotForVolume fetches all the snapshots for the given volume
+func GetSnapshotForVolume(volumeID string) (*apis.ZFSSnapshotList, error) {
+	listOptions := metav1.ListOptions{
+		LabelSelector: ZFSVolKey + "=" + volumeID,
+	}
+	snapList, err := snapbuilder.NewKubeclient().WithNamespace(OpenEBSNamespace).List(listOptions)
+	return snapList, err
+}
+
+// MarkForDeletion marks the volume for deletion by adding the annotation
+func MarkForDeletion(volumeName string) error {
+	zv, err := GetZFSVolume(volumeName)
+	if err != nil {
+		klog.Errorf("failed to get ZV %s: %v", volumeName, err)
+		return err
+	}
+
+	err = UpdateZFSVolumeAnnotation(zv)
+	if err != nil {
+		klog.Errorf("Failed to annotate the ZV with marked for deletion %s: %v", volumeName, err)
+		return err
+	}
+	return nil
+}
+
+// IsVolumeEligibleForDeletion checks if the volume can be deleted or not
+func IsVolumeEligibleForDeletion(volumeName string) (bool, error) {
+
+	zfsVol, err := GetZFSVolume(volumeName)
+	if err != nil {
+		return false, status.Errorf(
+			codes.Internal,
+			"failed to get ZFSVolume %s: %v",
+			volumeName,
+			err,
+		)
+	}
+	if zfsVol.Annotations[volbuilder.MarkForDeletionAnnotation] == "true" {
+		return true, nil
+	}
+	return false, nil
+}