cephfs: simplify error handling

This change replaces the sentinel errors in cephfs module with
standard errors created with errors.New().

Related: #1203

Signed-off-by: Sven Anderson <sven@redhat.com>

internal/cephfs/controllerserver.go

@@ -184,8 +184,7 @@ func (cs *ControllerServer) DeleteVolume(ctx context.Context, req *csi.DeleteVol
 		}
 
 		// All errors other than ErrVolumeNotFound should return an error back to the caller
-		var evnf ErrVolumeNotFound
+		if !errors.Is(err, ErrVolumeNotFound) {
-		if !errors.As(err, &evnf) {
 			return nil, status.Error(codes.Internal, err.Error())
 		}
 
@@ -221,8 +220,7 @@ func (cs *ControllerServer) DeleteVolume(ctx context.Context, req *csi.DeleteVol
 	if err = purgeVolume(ctx, volumeID(vID.FsSubvolName), cr, volOptions); err != nil {
 		klog.Errorf(util.Log(ctx, "failed to delete volume %s: %v"), volID, err)
 		// All errors other than ErrVolumeNotFound should return an error back to the caller
-		var evnf ErrVolumeNotFound
+		if !errors.Is(err, ErrVolumeNotFound) {
-		if !errors.As(err, &evnf) {
 			return nil, status.Error(codes.Internal, err.Error())
 		}
 	}

internal/cephfs/errors.go

@@ -16,49 +16,15 @@ limitations under the License.
 
 package cephfs
 
+import "errors"
+
+var (
 	// ErrInvalidVolID is returned when a CSI passed VolumeID is not conformant to any known volume ID
 	// formats.
-type ErrInvalidVolID struct {
+	ErrInvalidVolID = errors.New("invalid VolumeID")
-	err error
-}
-
-// Error returns a user presentable string of the error.
-func (e ErrInvalidVolID) Error() string {
-	return e.err.Error()
-}
-
-// Unwrap returns the encapsulated error of ErrInvalidVolID.
-func (e ErrInvalidVolID) Unwrap() error {
-	return e.err
-}
-
 	// ErrNonStaticVolume is returned when a volume is detected as not being
 	// statically provisioned.
-type ErrNonStaticVolume struct {
+	ErrNonStaticVolume = errors.New("volume not static")
-	err error
-}
-
-// Error returns a user presentable string of the error.
-func (e ErrNonStaticVolume) Error() string {
-	return e.err.Error()
-}
-
-// Unwrap returns the encapsulated error of ErrNonStaticVolume.
-func (e ErrNonStaticVolume) Unwrap() error {
-	return e.err
-}
-
 	// ErrVolumeNotFound is returned when a subvolume is not found in CephFS.
-type ErrVolumeNotFound struct {
+	ErrVolumeNotFound = errors.New("volume not found")
-	err error
+)
-}
-
-// Error returns a user presentable string of the error.
-func (e ErrVolumeNotFound) Error() string {
-	return e.err.Error()
-}
-
-// Unwrap returns the encapsulated error of ErrVolumeNotFound.
-func (e ErrVolumeNotFound) Unwrap() error {
-	return e.err
-}

internal/cephfs/fsjournal.go

@@ -72,8 +72,7 @@ func checkVolExists(ctx context.Context, volOptions *volumeOptions, secret map[s
 
 	_, err = getVolumeRootPathCeph(ctx, volOptions, cr, volumeID(vid.FsSubvolName))
 	if err != nil {
-		var evnf ErrVolumeNotFound
+		if errors.Is(err, ErrVolumeNotFound) {
-		if errors.As(err, &evnf) {
 			err = j.UndoReservation(ctx, volOptions.MetadataPool,
 				volOptions.MetadataPool, vid.FsSubvolName, volOptions.RequestName)
 			return nil, err

internal/cephfs/nodeserver.go

@@ -89,16 +89,14 @@ func (ns *NodeServer) NodeStageVolume(ctx context.Context, req *csi.NodeStageVol
 
 	volOptions, _, err := newVolumeOptionsFromVolID(ctx, string(volID), req.GetVolumeContext(), req.GetSecrets())
 	if err != nil {
-		var eivi ErrInvalidVolID
+		if !errors.Is(err, ErrInvalidVolID) {
-		if !errors.As(err, &eivi) {
 			return nil, status.Error(codes.Internal, err.Error())
 		}
 
 		// gets mon IPs from the supplied cluster info
 		volOptions, _, err = newVolumeOptionsFromStaticVolume(string(volID), req.GetVolumeContext())
 		if err != nil {
-			var ensv ErrNonStaticVolume
+			if !errors.Is(err, ErrNonStaticVolume) {
-			if !errors.As(err, &ensv) {
 				return nil, status.Error(codes.Internal, err.Error())
 			}
 

internal/cephfs/volume.go

@@ -70,7 +70,7 @@ func getVolumeRootPathCeph(ctx context.Context, volOptions *volumeOptions, cr *u
 		klog.Errorf(util.Log(ctx, "failed to get the rootpath for the vol %s(%s) stdError %s"), string(volID), err, stdErrString)
 
 		if strings.HasPrefix(stdErrString, errNotFoundString) {
-			return "", ErrVolumeNotFound{err}
+			return "", util.JoinErrors(ErrVolumeNotFound, err)
 		}
 
 		return "", err
@@ -215,7 +215,7 @@ func purgeVolume(ctx context.Context, volID volumeID, cr *util.Credentials, volO
 		klog.Errorf(util.Log(ctx, "failed to purge subvolume %s(%s) in fs %s"), string(volID), err, volOptions.FsName)
 
 		if strings.HasPrefix(err.Error(), errNotFoundString) {
-			return ErrVolumeNotFound{err}
+			return util.JoinErrors(ErrVolumeNotFound, err)
 		}
 
 		return err

internal/cephfs/volumeoptions.go

@@ -230,8 +230,8 @@ func newVolumeOptionsFromVolID(ctx context.Context, volID string, volOpt, secret
 	// before other errors
 	err := vi.DecomposeCSIID(volID)
 	if err != nil {
-		err = fmt.Errorf("error decoding volume ID (%s) (%s)", err, volID)
+		err = fmt.Errorf("error decoding volume ID (%s): %w", volID, err)
-		return nil, nil, ErrInvalidVolID{err}
+		return nil, nil, util.JoinErrors(ErrInvalidVolID, err)
 	}
 	volOptions.ClusterID = vi.ClusterID
 	vid.VolumeID = volID
@@ -372,7 +372,7 @@ func newVolumeOptionsFromStaticVolume(volID string, options map[string]string) (
 
 	val, ok := options["staticVolume"]
 	if !ok {
-		return nil, nil, ErrNonStaticVolume{err}
+		return nil, nil, ErrNonStaticVolume
 	}
 
 	if staticVol, err = strconv.ParseBool(val); err != nil {
@@ -380,7 +380,7 @@ func newVolumeOptionsFromStaticVolume(volID string, options map[string]string) (
 	}
 
 	if !staticVol {
-		return nil, nil, ErrNonStaticVolume{err}
+		return nil, nil, ErrNonStaticVolume
 	}
 
 	// Volume is static, and ProvisionVolume carries bool stating if it was provisioned, hence