nfs: make DeleteVolume (more) idempotent

Signed-off-by: Niels de Vos <ndevos@redhat.com>

internal/nfs/controller/controllerserver.go

@@ -18,7 +18,7 @@ package controller
 
 import (
 	"context"
-	"strings"
+	"errors"
 
 	"github.com/ceph/ceph-csi/internal/cephfs"
 	"github.com/ceph/ceph-csi/internal/cephfs/store"
@@ -147,11 +147,11 @@ func (cs *Server) DeleteVolume(
 
 	err = nfsVolume.DeleteExport()
 	// if the export does not exist, continue with deleting the backend volume
-	if err != nil && !strings.Contains(err.Error(), "Export does not exist") {
+	if err != nil && !errors.Is(err, ErrNotFound) {
 		return nil, status.Errorf(codes.InvalidArgument, "failed to delete export: %v", err)
 	}
 
-	log.DebugLog(ctx, "deleted NFS-export: %s", nfsVolume)
+	log.DebugLog(ctx, "NFS-export %q has been deleted", nfsVolume)
 
 	return cs.backendServer.DeleteVolume(ctx, req)
 }

internal/nfs/controller/errors.go

@@ -0,0 +1,43 @@
+/*
+Copyright 2022 The Ceph-CSI Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package controller
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	// ErrNotConnected is returned when components from the NFS
+	// ControllerServer can not connect to the Ceph cluster or NFS-Ganesha
+	// service.
+	ErrNotConnected = errors.New("not connected")
+
+	// ErrNotFound is a generic error that is the parent of other "not
+	// found" failures. Callers can check if something was "not found",
+	// even if the actual error is more specific.
+	ErrNotFound = errors.New("not found")
+
+	// ErrExportNotFound is returned by components that communicate with the
+	// NFS-Ganesha service, and have identified that the NFS-Export does
+	// not exist (anymore). This error is also a ErrNotFound.
+	ErrExportNotFound = fmt.Errorf("NFS-export %w", ErrNotFound)
+
+	// ErrFilesystemNotFound is returned in case the filesystem
+	// does not exist.
+	ErrFilesystemNotFound = fmt.Errorf("filesystem %w", ErrNotFound)
+)

internal/nfs/controller/volume.go

@@ -18,6 +18,7 @@ package controller
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"strings"
 
@@ -124,7 +125,7 @@ func (nv *NFSVolume) GetExportPath() string {
 // a new NFS-export for the volume on the Ceph managed NFS-server.
 func (nv *NFSVolume) CreateExport(backend *csi.Volume) error {
 	if !nv.connected {
-		return fmt.Errorf("can not created export for %q: not connected", nv)
+		return fmt.Errorf("can not created export for %q: %w", nv, ErrNotConnected)
 	}
 
 	fs := backend.VolumeContext["fsName"]
@@ -213,6 +214,8 @@ func (nv *NFSVolume) DeleteExport() error {
 		return nil
 	case strings.Contains(err.Error(), "API call not implemented"): // try with the old command
 		break
+	case strings.Contains(err.Error(), "Export does not exist"):
+		return ErrExportNotFound
 	default: // any other error
 		return fmt.Errorf("failed to remove %q from NFS-cluster %q: "+
 			"%w", nv, nfsCluster, err)
@@ -251,17 +254,21 @@ func (nv *NFSVolume) deleteExportCommand(cmd, nfsCluster string) []string {
 // getNFSCluster fetches the NFS-cluster name from the CephFS journal.
 func (nv *NFSVolume) getNFSCluster() (string, error) {
 	if !nv.connected {
-		return "", fmt.Errorf("can not get NFS-cluster for %q: not connected", nv)
+		return "", fmt.Errorf("can not get NFS-cluster for %q: %w", nv, ErrNotConnected)
 	}
 
 	fs := fscore.NewFileSystem(nv.conn)
 	fsName, err := fs.GetFsName(nv.ctx, nv.fscID)
-	if err != nil {
+	if err != nil && errors.Is(err, util.ErrPoolNotFound) {
+		return "", fmt.Errorf("%w for ID %x: %v", ErrFilesystemNotFound, nv.fscID, err)
+	} else if err != nil {
 		return "", fmt.Errorf("failed to get filesystem name for ID %x: %w", nv.fscID, err)
 	}
 
 	mdPool, err := fs.GetMetadataPool(nv.ctx, fsName)
-	if err != nil {
+	if err != nil && errors.Is(err, util.ErrPoolNotFound) {
+		return "", fmt.Errorf("metadata pool for %q %w: %v", fsName, ErrNotFound, err)
+	} else if err != nil {
 		return "", fmt.Errorf("failed to get metadata pool for %q: %w", fsName, err)
 	}
 
@@ -273,8 +280,10 @@ func (nv *NFSVolume) getNFSCluster() (string, error) {
 	defer j.Destroy()
 
 	clusterName, err := j.FetchAttribute(nv.ctx, mdPool, nv.objectUUID, clusterNameKey)
-	if err != nil {
-		return "", fmt.Errorf("failed to get cluster name: %w", err)
+	if err != nil && errors.Is(err, util.ErrPoolNotFound) || errors.Is(err, util.ErrKeyNotFound) {
+		return "", fmt.Errorf("cluster name for %q %w: %v", nv.objectUUID, ErrNotFound, err)
+	} else if err != nil {
+		return "", fmt.Errorf("failed to get cluster name for %q: %w", nv.objectUUID, err)
 	}
 
 	return clusterName, nil
@@ -283,17 +292,21 @@ func (nv *NFSVolume) getNFSCluster() (string, error) {
 // setNFSCluster stores the NFS-cluster name in the CephFS journal.
 func (nv *NFSVolume) setNFSCluster(clusterName string) error {
 	if !nv.connected {
-		return fmt.Errorf("can not set NFS-cluster for %q: not connected", nv)
+		return fmt.Errorf("can not set NFS-cluster for %q: %w", nv, ErrNotConnected)
 	}
 
 	fs := fscore.NewFileSystem(nv.conn)
 	fsName, err := fs.GetFsName(nv.ctx, nv.fscID)
-	if err != nil {
+	if err != nil && errors.Is(err, util.ErrPoolNotFound) {
+		return fmt.Errorf("%w for ID %x: %v", ErrFilesystemNotFound, nv.fscID, err)
+	} else if err != nil {
 		return fmt.Errorf("failed to get filesystem name for ID %x: %w", nv.fscID, err)
 	}
 
 	mdPool, err := fs.GetMetadataPool(nv.ctx, fsName)
-	if err != nil {
+	if err != nil && errors.Is(err, util.ErrPoolNotFound) {
+		return fmt.Errorf("metadata pool for %q %w: %v", fsName, ErrNotFound, err)
+	} else if err != nil {
 		return fmt.Errorf("failed to get metadata pool for %q: %w", fsName, err)
 	}