/*
Copyright 2018 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 rbd

import (
	"context"
	"errors"
	"fmt"
	"os"
	"strconv"
	"strings"

	csicommon "github.com/ceph/ceph-csi/internal/csi-common"
	"github.com/ceph/ceph-csi/internal/journal"
	"github.com/ceph/ceph-csi/internal/util"

	librbd "github.com/ceph/go-ceph/rbd"
	"github.com/container-storage-interface/spec/lib/go/csi"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"k8s.io/kubernetes/pkg/util/resizefs"
	mount "k8s.io/mount-utils"
	utilexec "k8s.io/utils/exec"
)

// NodeServer struct of ceph rbd driver with supported methods of CSI
// node server spec.
type NodeServer struct {
	*csicommon.DefaultNodeServer
	mounter mount.Interface
	// A map storing all volumes with ongoing operations so that additional operations
	// for that same volume (as defined by VolumeID) return an Aborted error
	VolumeLocks *util.VolumeLocks
}

// stageTransaction struct represents the state a transaction was when it either completed
// or failed
// this transaction state can be used to rollback the transaction.
type stageTransaction struct {
	// isStagePathCreated represents whether the mount path to stage the volume on was created or not
	isStagePathCreated bool
	// isMounted represents if the volume was mounted or not
	isMounted bool
	// isEncrypted represents if the volume was encrypted or not
	isEncrypted bool
	// devicePath represents the path where rbd device is mapped
	devicePath string
}

const (
	// values for xfsHasReflink
	xfsReflinkUnset int = iota
	xfsReflinkNoSupport
	xfsReflinkSupport
)

var (
	kernelRelease = ""
	// deepFlattenSupport holds the list of kernel which support mapping rbd
	// image with deep-flatten image feature
	// nolint:gomnd // numbers specify Kernel versions.
	deepFlattenSupport = []util.KernelVersion{
		{
			Version:      5,
			PatchLevel:   1,
			SubLevel:     0,
			ExtraVersion: 0,
			Distribution: "",
			Backport:     false,
		}, // standard 5.1+ versions
		{
			Version:      4,
			PatchLevel:   18,
			SubLevel:     0,
			ExtraVersion: 193,
			Distribution: ".el8",
			Backport:     true,
		}, // RHEL 8.2
	}

	// xfsHasReflink is set by xfsSupportsReflink(), use the function when
	// checking the support for reflink
	xfsHasReflink = xfsReflinkUnset
)

// NodeStageVolume mounts the volume to a staging path on the node.
// Implementation notes:
// - stagingTargetPath is the directory passed in the request where the volume needs to be staged
//   - We stage the volume into a directory, named after the VolumeID inside stagingTargetPath if
//    it is a file system
//   - We stage the volume into a file, named after the VolumeID inside stagingTargetPath if it is
//    a block volume
// - Order of operation execution: (useful for defer stacking and when Unstaging to ensure steps
//	are done in reverse, this is done in undoStagingTransaction)
//   - Stash image metadata under staging path
//   - Map the image (creates a device)
//   - Create the staging file/directory under staging path
//   - Stage the device (mount the device mapped for image)
// TODO: make this function less complex.
func (ns *NodeServer) NodeStageVolume(ctx context.Context, req *csi.NodeStageVolumeRequest) (*csi.NodeStageVolumeResponse, error) {
	if err := util.ValidateNodeStageVolumeRequest(req); err != nil {
		return nil, err
	}

	isBlock := req.GetVolumeCapability().GetBlock() != nil
	disableInUseChecks := false
	// MULTI_NODE_MULTI_WRITER is supported by default for Block access type volumes
	if req.VolumeCapability.AccessMode.Mode == csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER {
		if !isBlock {
			util.WarningLog(ctx, "MULTI_NODE_MULTI_WRITER currently only supported with volumes of access type `block`, invalid AccessMode for volume: %v", req.GetVolumeId())
			return nil, status.Error(codes.InvalidArgument, "rbd: RWX access mode request is only valid for volumes with access type `block`")
		}

		disableInUseChecks = true
	}

	volID := req.GetVolumeId()

	cr, err := util.NewUserCredentials(req.GetSecrets())
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}
	defer cr.DeleteCredentials()

	if acquired := ns.VolumeLocks.TryAcquire(volID); !acquired {
		util.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volID)
		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volID)
	}
	defer ns.VolumeLocks.Release(volID)

	stagingParentPath := req.GetStagingTargetPath()
	stagingTargetPath := stagingParentPath + "/" + volID

	// check is it a static volume
	staticVol := false
	val, ok := req.GetVolumeContext()["staticVolume"]
	if ok {
		if staticVol, err = strconv.ParseBool(val); err != nil {
			return nil, status.Error(codes.InvalidArgument, err.Error())
		}
	}

	// check if stagingPath is already mounted
	isNotMnt, err := isNotMountPoint(ns.mounter, stagingTargetPath)
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	} else if !isNotMnt {
		util.DebugLog(ctx, "rbd: volume %s is already mounted to %s, skipping", volID, stagingTargetPath)
		return &csi.NodeStageVolumeResponse{}, nil
	}

	// throw error when imageFeatures parameter is missing or empty
	// for backward compatibility, ignore error for non-static volumes from older cephcsi version
	if imageFeatures, ok := req.GetVolumeContext()["imageFeatures"]; checkImageFeatures(imageFeatures, ok, staticVol) {
		return nil, status.Error(codes.InvalidArgument, "missing required parameter imageFeatures")
	}

	volOptions, err := genVolFromVolumeOptions(ctx, req.GetVolumeContext(), req.GetSecrets(), disableInUseChecks)
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	volOptions.ThickProvision = isThickProvisionRequest(req.GetVolumeContext())

	// get rbd image name from the volume journal
	// for static volumes, the image name is actually the volume ID itself
	switch {
	case staticVol:
		volOptions.RbdImageName = volID
	default:
		var vi util.CSIIdentifier
		var imageAttributes *journal.ImageAttributes
		err = vi.DecomposeCSIID(volID)
		if err != nil {
			err = fmt.Errorf("error decoding volume ID (%s): %w", volID, err)
			return nil, status.Error(codes.Internal, err.Error())
		}

		j, connErr := volJournal.Connect(volOptions.Monitors, volOptions.RadosNamespace, cr)
		if connErr != nil {
			util.ErrorLog(ctx, "failed to establish cluster connection: %v", connErr)
			return nil, status.Error(codes.Internal, connErr.Error())
		}
		defer j.Destroy()

		imageAttributes, err = j.GetImageAttributes(
			ctx, volOptions.Pool, vi.ObjectUUID, false)
		if err != nil {
			err = fmt.Errorf("error fetching image attributes for volume ID (%s): %w", volID, err)
			return nil, status.Error(codes.Internal, err.Error())
		}
		volOptions.RbdImageName = imageAttributes.ImageName
	}

	volOptions.VolID = volID
	transaction := stageTransaction{}

	volOptions.MapOptions = req.GetVolumeContext()["mapOptions"]
	volOptions.UnmapOptions = req.GetVolumeContext()["unmapOptions"]

	// Stash image details prior to mapping the image (useful during Unstage as it has no
	// voloptions passed to the RPC as per the CSI spec)
	err = stashRBDImageMetadata(volOptions, stagingParentPath)
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}
	defer func() {
		if err != nil {
			ns.undoStagingTransaction(ctx, req, transaction, volOptions)
		}
	}()

	// perform the actual staging and if this fails, have undoStagingTransaction
	// cleans up for us
	transaction, err = ns.stageTransaction(ctx, req, volOptions, staticVol)
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	util.DebugLog(ctx, "rbd: successfully mounted volume %s to stagingTargetPath %s", req.GetVolumeId(), stagingTargetPath)

	return &csi.NodeStageVolumeResponse{}, nil
}

func (ns *NodeServer) stageTransaction(ctx context.Context, req *csi.NodeStageVolumeRequest, volOptions *rbdVolume, staticVol bool) (stageTransaction, error) {
	transaction := stageTransaction{}

	var err error
	var readOnly bool
	var feature bool
	var depth uint

	var cr *util.Credentials
	cr, err = util.NewUserCredentials(req.GetSecrets())
	if err != nil {
		return transaction, err
	}
	defer cr.DeleteCredentials()

	err = volOptions.Connect(cr)
	if err != nil {
		util.ErrorLog(ctx, "failed to connect to volume %v: %v", volOptions.RbdImageName, err)
		return transaction, err
	}
	defer volOptions.Destroy()

	// Allow image to be mounted on multiple nodes if it is ROX
	if req.VolumeCapability.AccessMode.Mode == csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY {
		util.ExtendedLog(ctx, "setting disableInUseChecks on rbd volume to: %v", req.GetVolumeId)
		volOptions.DisableInUseChecks = true
		volOptions.readOnly = true
	}

	if kernelRelease == "" {
		// fetch the current running kernel info
		kernelRelease, err = util.GetKernelVersion()
		if err != nil {
			return transaction, err
		}
	}
	if !util.CheckKernelSupport(kernelRelease, deepFlattenSupport) && !skipForceFlatten {
		feature, err = volOptions.checkImageChainHasFeature(ctx, librbd.FeatureDeepFlatten)
		if err != nil {
			return transaction, err
		}
		depth, err = volOptions.getCloneDepth(ctx)
		if err != nil {
			return transaction, err
		}
		if feature || depth != 0 {
			err = volOptions.flattenRbdImage(ctx, cr, true, rbdHardMaxCloneDepth, rbdSoftMaxCloneDepth)
			if err != nil {
				return transaction, err
			}
		}
	}
	// Mapping RBD image
	var devicePath string
	devicePath, err = attachRBDImage(ctx, volOptions, cr)
	if err != nil {
		return transaction, err
	}
	transaction.devicePath = devicePath
	util.DebugLog(ctx, "rbd image: %s/%s was successfully mapped at %s\n",
		req.GetVolumeId(), volOptions.Pool, devicePath)

	if volOptions.isEncrypted() {
		devicePath, err = ns.processEncryptedDevice(ctx, volOptions, devicePath)
		if err != nil {
			return transaction, err
		}
		transaction.isEncrypted = true
	}

	stagingTargetPath := getStagingTargetPath(req)

	isBlock := req.GetVolumeCapability().GetBlock() != nil
	err = ns.createStageMountPoint(ctx, stagingTargetPath, isBlock)
	if err != nil {
		return transaction, err
	}

	transaction.isStagePathCreated = true

	// nodeStage Path
	readOnly, err = ns.mountVolumeToStagePath(ctx, req, staticVol, stagingTargetPath, devicePath)
	if err != nil {
		return transaction, err
	}
	transaction.isMounted = true

	if !readOnly {
		// #nosec - allow anyone to write inside the target path
		err = os.Chmod(stagingTargetPath, 0777)
	}
	return transaction, err
}

func (ns *NodeServer) undoStagingTransaction(ctx context.Context, req *csi.NodeStageVolumeRequest, transaction stageTransaction, volOptions *rbdVolume) {
	var err error

	stagingTargetPath := getStagingTargetPath(req)
	if transaction.isMounted {
		err = ns.mounter.Unmount(stagingTargetPath)
		if err != nil {
			util.ErrorLog(ctx, "failed to unmount stagingtargetPath: %s with error: %v", stagingTargetPath, err)
			return
		}
	}

	// remove the file/directory created on staging path
	if transaction.isStagePathCreated {
		err = os.Remove(stagingTargetPath)
		if err != nil {
			util.ErrorLog(ctx, "failed to remove stagingtargetPath: %s with error: %v", stagingTargetPath, err)
			// continue on failure to unmap the image, as leaving stale images causes more issues than a stale file/directory
		}
	}

	volID := req.GetVolumeId()

	// Unmapping rbd device
	if transaction.devicePath != "" {
		err = detachRBDDevice(ctx, transaction.devicePath, volID, volOptions.UnmapOptions, transaction.isEncrypted)
		if err != nil {
			util.ErrorLog(ctx, "failed to unmap rbd device: %s for volume %s with error: %v", transaction.devicePath, volID, err)
			// continue on failure to delete the stash file, as kubernetes will fail to delete the staging path otherwise
		}
	}

	// Cleanup the stashed image metadata
	if err = cleanupRBDImageMetadataStash(req.GetStagingTargetPath()); err != nil {
		util.ErrorLog(ctx, "failed to cleanup image metadata stash (%v)", err)
		return
	}
}

func (ns *NodeServer) createStageMountPoint(ctx context.Context, mountPath string, isBlock bool) error {
	if isBlock {
		// #nosec:G304, intentionally creating file mountPath, not a security issue
		pathFile, err := os.OpenFile(mountPath, os.O_CREATE|os.O_RDWR, 0600)
		if err != nil {
			util.ErrorLog(ctx, "failed to create mountPath:%s with error: %v", mountPath, err)
			return status.Error(codes.Internal, err.Error())
		}
		if err = pathFile.Close(); err != nil {
			util.ErrorLog(ctx, "failed to close mountPath:%s with error: %v", mountPath, err)
			return status.Error(codes.Internal, err.Error())
		}

		return nil
	}

	err := os.Mkdir(mountPath, 0750)
	if err != nil {
		if !os.IsExist(err) {
			util.ErrorLog(ctx, "failed to create mountPath:%s with error: %v", mountPath, err)
			return status.Error(codes.Internal, err.Error())
		}
	}

	return nil
}

// NodePublishVolume mounts the volume mounted to the device path to the target
// path.
func (ns *NodeServer) NodePublishVolume(ctx context.Context, req *csi.NodePublishVolumeRequest) (*csi.NodePublishVolumeResponse, error) {
	err := util.ValidateNodePublishVolumeRequest(req)
	if err != nil {
		return nil, err
	}
	targetPath := req.GetTargetPath()
	isBlock := req.GetVolumeCapability().GetBlock() != nil
	stagingPath := req.GetStagingTargetPath()
	volID := req.GetVolumeId()
	stagingPath += "/" + volID

	if acquired := ns.VolumeLocks.TryAcquire(volID); !acquired {
		util.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volID)
		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volID)
	}
	defer ns.VolumeLocks.Release(volID)

	// Check if that target path exists properly
	notMnt, err := ns.createTargetMountPath(ctx, targetPath, isBlock)
	if err != nil {
		return nil, err
	}

	if !notMnt {
		return &csi.NodePublishVolumeResponse{}, nil
	}

	// Publish Path
	err = ns.mountVolume(ctx, stagingPath, req)
	if err != nil {
		return nil, err
	}

	util.DebugLog(ctx, "rbd: successfully mounted stagingPath %s to targetPath %s", stagingPath, targetPath)
	return &csi.NodePublishVolumeResponse{}, nil
}

func (ns *NodeServer) mountVolumeToStagePath(ctx context.Context, req *csi.NodeStageVolumeRequest, staticVol bool, stagingPath, devicePath string) (bool, error) {
	readOnly := false
	fsType := req.GetVolumeCapability().GetMount().GetFsType()
	diskMounter := &mount.SafeFormatAndMount{Interface: ns.mounter, Exec: utilexec.New()}
	// rbd images are thin-provisioned and return zeros for unwritten areas.  A freshly created
	// image will not benefit from discard and we also want to avoid as much unnecessary zeroing
	// as possible.  Open-code mkfs here because FormatAndMount() doesn't accept custom mkfs
	// options.
	//
	// Note that "freshly" is very important here.  While discard is more of a nice to have,
	// lazy_journal_init=1 is plain unsafe if the image has been written to before and hasn't
	// been zeroed afterwards (unlike the name suggests, it leaves the journal completely
	// uninitialized and carries a risk until the journal is overwritten and wraps around for
	// the first time).
	existingFormat, err := diskMounter.GetDiskFormat(devicePath)
	if err != nil {
		util.ErrorLog(ctx, "failed to get disk format for path %s, error: %v", devicePath, err)
		return readOnly, err
	}

	opt := []string{"_netdev"}
	opt = csicommon.ConstructMountOptions(opt, req.GetVolumeCapability())
	isBlock := req.GetVolumeCapability().GetBlock() != nil
	rOnly := "ro"

	if req.VolumeCapability.AccessMode.Mode == csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY ||
		req.VolumeCapability.AccessMode.Mode == csi.VolumeCapability_AccessMode_SINGLE_NODE_READER_ONLY {
		if !csicommon.MountOptionContains(opt, rOnly) {
			opt = append(opt, rOnly)
		}
	}
	if csicommon.MountOptionContains(opt, rOnly) {
		readOnly = true
	}

	if fsType == "xfs" {
		opt = append(opt, "nouuid")
	}

	if existingFormat == "" && !staticVol && !readOnly {
		args := []string{}
		switch fsType {
		case "ext4":
			args = []string{"-m0", "-Enodiscard,lazy_itable_init=1,lazy_journal_init=1", devicePath}
		case "xfs":
			args = []string{"-K", devicePath}
			// always disable reflink
			// TODO: make enabling an option, see ceph/ceph-csi#1256
			if ns.xfsSupportsReflink() {
				args = append(args, "-m", "reflink=0")
			}
		}
		if len(args) > 0 {
			cmdOut, cmdErr := diskMounter.Exec.Command("mkfs."+fsType, args...).CombinedOutput()
			if cmdErr != nil {
				util.ErrorLog(ctx, "failed to run mkfs error: %v, output: %v", cmdErr, string(cmdOut))
				return readOnly, cmdErr
			}
		}
	}

	if isBlock {
		opt = append(opt, "bind")
		err = diskMounter.Mount(devicePath, stagingPath, fsType, opt)
	} else {
		err = diskMounter.FormatAndMount(devicePath, stagingPath, fsType, opt)
	}
	if err != nil {
		util.ErrorLog(ctx,
			"failed to mount device path (%s) to staging path (%s) for volume "+
				"(%s) error: %s Check dmesg logs if required.",
			devicePath,
			stagingPath,
			req.GetVolumeId(),
			err)
	}
	return readOnly, err
}

func (ns *NodeServer) mountVolume(ctx context.Context, stagingPath string, req *csi.NodePublishVolumeRequest) error {
	// Publish Path
	fsType := req.GetVolumeCapability().GetMount().GetFsType()
	readOnly := req.GetReadonly()
	mountOptions := []string{"bind", "_netdev"}
	isBlock := req.GetVolumeCapability().GetBlock() != nil
	targetPath := req.GetTargetPath()

	mountOptions = csicommon.ConstructMountOptions(mountOptions, req.GetVolumeCapability())

	util.DebugLog(ctx, "target %v\nisBlock %v\nfstype %v\nstagingPath %v\nreadonly %v\nmountflags %v\n",
		targetPath, isBlock, fsType, stagingPath, readOnly, mountOptions)

	if readOnly {
		mountOptions = append(mountOptions, "ro")
	}
	if err := util.Mount(stagingPath, targetPath, fsType, mountOptions); err != nil {
		return status.Error(codes.Internal, err.Error())
	}

	return nil
}

func (ns *NodeServer) createTargetMountPath(ctx context.Context, mountPath string, isBlock bool) (bool, error) {
	// Check if that mount path exists properly
	notMnt, err := mount.IsNotMountPoint(ns.mounter, mountPath)
	if err == nil {
		return notMnt, err
	}
	if !os.IsNotExist(err) {
		return false, status.Error(codes.Internal, err.Error())
	}
	if isBlock {
		// #nosec
		pathFile, e := os.OpenFile(mountPath, os.O_CREATE|os.O_RDWR, 0750)
		if e != nil {
			util.DebugLog(ctx, "Failed to create mountPath:%s with error: %v", mountPath, err)
			return notMnt, status.Error(codes.Internal, e.Error())
		}
		if err = pathFile.Close(); err != nil {
			util.DebugLog(ctx, "Failed to close mountPath:%s with error: %v", mountPath, err)
			return notMnt, status.Error(codes.Internal, err.Error())
		}
	} else {
		// Create a mountpath directory
		if err = util.CreateMountPoint(mountPath); err != nil {
			return notMnt, status.Error(codes.Internal, err.Error())
		}
	}
	notMnt = true
	return notMnt, err
}

// NodeUnpublishVolume unmounts the volume from the target path.
func (ns *NodeServer) NodeUnpublishVolume(ctx context.Context, req *csi.NodeUnpublishVolumeRequest) (*csi.NodeUnpublishVolumeResponse, error) {
	err := util.ValidateNodeUnpublishVolumeRequest(req)
	if err != nil {
		return nil, err
	}

	targetPath := req.GetTargetPath()
	volID := req.GetVolumeId()

	if acquired := ns.VolumeLocks.TryAcquire(volID); !acquired {
		util.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volID)
		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volID)
	}
	defer ns.VolumeLocks.Release(volID)

	notMnt, err := mount.IsNotMountPoint(ns.mounter, targetPath)
	if err != nil {
		if os.IsNotExist(err) {
			// targetPath has already been deleted
			util.DebugLog(ctx, "targetPath: %s has already been deleted", targetPath)
			return &csi.NodeUnpublishVolumeResponse{}, nil
		}
		return nil, status.Error(codes.NotFound, err.Error())
	}
	if notMnt {
		if err = os.RemoveAll(targetPath); err != nil {
			return nil, status.Error(codes.Internal, err.Error())
		}
		return &csi.NodeUnpublishVolumeResponse{}, nil
	}

	if err = ns.mounter.Unmount(targetPath); err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	if err = os.RemoveAll(targetPath); err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	util.DebugLog(ctx, "rbd: successfully unbound volume %s from %s", req.GetVolumeId(), targetPath)

	return &csi.NodeUnpublishVolumeResponse{}, nil
}

// getStagingTargetPath concats either NodeStageVolumeRequest's or
// NodeUnstageVolumeRequest's target path with the volumeID.
func getStagingTargetPath(req interface{}) string {
	switch vr := req.(type) {
	case *csi.NodeStageVolumeRequest:
		return vr.GetStagingTargetPath() + "/" + vr.GetVolumeId()
	case *csi.NodeUnstageVolumeRequest:
		return vr.GetStagingTargetPath() + "/" + vr.GetVolumeId()
	}

	return ""
}

// NodeUnstageVolume unstages the volume from the staging path.
func (ns *NodeServer) NodeUnstageVolume(ctx context.Context, req *csi.NodeUnstageVolumeRequest) (*csi.NodeUnstageVolumeResponse, error) {
	var err error
	if err = util.ValidateNodeUnstageVolumeRequest(req); err != nil {
		return nil, err
	}

	volID := req.GetVolumeId()

	if acquired := ns.VolumeLocks.TryAcquire(volID); !acquired {
		util.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volID)
		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volID)
	}
	defer ns.VolumeLocks.Release(volID)

	stagingParentPath := req.GetStagingTargetPath()
	stagingTargetPath := getStagingTargetPath(req)

	notMnt, err := mount.IsNotMountPoint(ns.mounter, stagingTargetPath)
	if err != nil {
		if !os.IsNotExist(err) {
			return nil, status.Error(codes.NotFound, err.Error())
		}
		// Continue on ENOENT errors as we may still have the image mapped
		notMnt = true
	}
	if !notMnt {
		// Unmounting the image
		err = ns.mounter.Unmount(stagingTargetPath)
		if err != nil {
			util.ExtendedLog(ctx, "failed to unmount targetPath: %s with error: %v", stagingTargetPath, err)
			return nil, status.Error(codes.Internal, err.Error())
		}
		util.DebugLog(ctx, "successfully unmounted volume (%s) from staging path (%s)",
			req.GetVolumeId(), stagingTargetPath)
	}

	if err = os.Remove(stagingTargetPath); err != nil {
		// Any error is critical as Staging path is expected to be empty by Kubernetes, it otherwise
		// keeps invoking Unstage. Hence any errors removing files within this path is a critical
		// error
		if !os.IsNotExist(err) {
			util.ErrorLog(ctx, "failed to remove staging target path (%s): (%v)", stagingTargetPath, err)
			return nil, status.Error(codes.Internal, err.Error())
		}
	}

	imgInfo, err := lookupRBDImageMetadataStash(stagingParentPath)
	if err != nil {
		util.UsefulLog(ctx, "failed to find image metadata: %v", err)
		// It is an error if it was mounted, as we should have found the image metadata file with
		// no errors
		if !notMnt {
			return nil, status.Error(codes.Internal, err.Error())
		}

		// If not mounted, and error is anything other than metadata file missing, it is an error
		if !errors.Is(err, ErrMissingStash) {
			return nil, status.Error(codes.Internal, err.Error())
		}

		// It was not mounted and image metadata is also missing, we are done as the last step in
		// in the staging transaction is complete
		return &csi.NodeUnstageVolumeResponse{}, nil
	}

	// Unmapping rbd device
	imageSpec := imgInfo.String()
	if err = detachRBDImageOrDeviceSpec(ctx, imageSpec, true, imgInfo.NbdAccess, imgInfo.Encrypted, req.GetVolumeId(), imgInfo.UnmapOptions); err != nil {
		util.ErrorLog(ctx, "error unmapping volume (%s) from staging path (%s): (%v)", req.GetVolumeId(), stagingTargetPath, err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	util.DebugLog(ctx, "successfully unmapped volume (%s)", req.GetVolumeId())

	if err = cleanupRBDImageMetadataStash(stagingParentPath); err != nil {
		util.ErrorLog(ctx, "failed to cleanup image metadata stash (%v)", err)
		return nil, status.Error(codes.Internal, err.Error())
	}

	return &csi.NodeUnstageVolumeResponse{}, nil
}

// NodeExpandVolume resizes rbd volumes.
func (ns *NodeServer) NodeExpandVolume(ctx context.Context, req *csi.NodeExpandVolumeRequest) (*csi.NodeExpandVolumeResponse, error) {
	volumeID := req.GetVolumeId()
	if volumeID == "" {
		return nil, status.Error(codes.InvalidArgument, "volume ID must be provided")
	}

	// Get volume path
	// With Kubernetes version>=v1.19.0, expand request carries volume_path and
	// staging_target_path, what csi requires is staging_target_path.
	volumePath := req.GetStagingTargetPath()
	if volumePath == "" {
		// If Kubernetes version < v1.19.0 the volume_path would be
		// having the staging_target_path information
		volumePath = req.GetVolumePath()
	}
	if volumePath == "" {
		return nil, status.Error(codes.InvalidArgument, "volume path must be provided")
	}

	if acquired := ns.VolumeLocks.TryAcquire(volumeID); !acquired {
		util.ErrorLog(ctx, util.VolumeOperationAlreadyExistsFmt, volumeID)
		return nil, status.Errorf(codes.Aborted, util.VolumeOperationAlreadyExistsFmt, volumeID)
	}
	defer ns.VolumeLocks.Release(volumeID)

	devicePath, err := getDevicePath(ctx, volumePath)
	if err != nil {
		return nil, status.Error(codes.Internal, err.Error())
	}

	diskMounter := &mount.SafeFormatAndMount{Interface: ns.mounter, Exec: utilexec.New()}
	// TODO check size and return success or error
	volumePath += "/" + volumeID
	resizer := resizefs.NewResizeFs(diskMounter)
	ok, err := resizer.Resize(devicePath, volumePath)
	if !ok {
		return nil, status.Errorf(codes.Internal, "rbd: resize failed on path %s, error: %v", req.GetVolumePath(), err)
	}
	return &csi.NodeExpandVolumeResponse{}, nil
}

func getDevicePath(ctx context.Context, volumePath string) (string, error) {
	imgInfo, err := lookupRBDImageMetadataStash(volumePath)
	if err != nil {
		util.ErrorLog(ctx, "failed to find image metadata: %v", err)
	}
	device, found := findDeviceMappingImage(ctx, imgInfo.Pool, imgInfo.RadosNamespace, imgInfo.ImageName, imgInfo.NbdAccess)
	if found {
		return device, nil
	}
	return "", fmt.Errorf("failed to get device for stagingtarget path %v", volumePath)
}

// NodeGetCapabilities returns the supported capabilities of the node server.
func (ns *NodeServer) NodeGetCapabilities(ctx context.Context, req *csi.NodeGetCapabilitiesRequest) (*csi.NodeGetCapabilitiesResponse, error) {
	return &csi.NodeGetCapabilitiesResponse{
		Capabilities: []*csi.NodeServiceCapability{
			{
				Type: &csi.NodeServiceCapability_Rpc{
					Rpc: &csi.NodeServiceCapability_RPC{
						Type: csi.NodeServiceCapability_RPC_STAGE_UNSTAGE_VOLUME,
					},
				},
			},
			{
				Type: &csi.NodeServiceCapability_Rpc{
					Rpc: &csi.NodeServiceCapability_RPC{
						Type: csi.NodeServiceCapability_RPC_GET_VOLUME_STATS,
					},
				},
			},
			{
				Type: &csi.NodeServiceCapability_Rpc{
					Rpc: &csi.NodeServiceCapability_RPC{
						Type: csi.NodeServiceCapability_RPC_EXPAND_VOLUME,
					},
				},
			},
		},
	}, nil
}

func (ns *NodeServer) processEncryptedDevice(ctx context.Context, volOptions *rbdVolume, devicePath string) (string, error) {
	imageSpec := volOptions.String()
	encrypted, err := volOptions.checkRbdImageEncrypted(ctx)
	if err != nil {
		util.ErrorLog(ctx, "failed to get encryption status for rbd image %s: %v",
			imageSpec, err)
		return "", err
	}

	switch {
	case encrypted == rbdImageRequiresEncryption:
		// If we get here, it means the image was created with a
		// ceph-csi version that creates a passphrase for the encrypted
		// device in NodeStage. New versions moved that to
		// CreateVolume.
		// Use the same setupEncryption() as CreateVolume does, and
		// continue with the common process to crypt-format the device.
		err = volOptions.setupEncryption(ctx)
		if err != nil {
			util.ErrorLog(ctx, "failed to setup encryption for rbd"+
				"image %s: %v", imageSpec, err)
			return "", err
		}

		// make sure we continue with the encrypting of the device
		fallthrough
	case encrypted == rbdImageEncryptionPrepared:
		diskMounter := &mount.SafeFormatAndMount{Interface: ns.mounter, Exec: utilexec.New()}
		// TODO: update this when adding support for static (pre-provisioned) PVs
		var existingFormat string
		existingFormat, err = diskMounter.GetDiskFormat(devicePath)
		if err != nil {
			return "", fmt.Errorf("failed to get disk format for path %s: %w", devicePath, err)
		}

		switch existingFormat {
		case "":
			err = volOptions.encryptDevice(ctx, devicePath)
			if err != nil {
				return "", fmt.Errorf("failed to encrypt rbd image %s: %w", imageSpec, err)
			}
		case "crypt", "crypto_LUKS":
			util.WarningLog(ctx, "rbd image %s is encrypted, but encryption state was not updated",
				imageSpec)
			err = volOptions.ensureEncryptionMetadataSet(rbdImageEncrypted)
			if err != nil {
				return "", fmt.Errorf("failed to update encryption state for rbd image %s", imageSpec)
			}
		default:
			return "", fmt.Errorf("can not encrypt rbdImage %s that already has file system: %s",
				imageSpec, existingFormat)
		}
	case encrypted != rbdImageEncrypted:
		return "", fmt.Errorf("rbd image %s found mounted with unexpected encryption status %s",
			imageSpec, encrypted)
	}

	devicePath, err = volOptions.openEncryptedDevice(ctx, devicePath)
	if err != nil {
		return "", err
	}

	return devicePath, nil
}

// xfsSupportsReflink checks if mkfs.xfs supports the "-m reflink=0|1"
// argument. In case it is supported, return true.
func (ns *NodeServer) xfsSupportsReflink() bool {
	// return cached value, if set
	if xfsHasReflink != xfsReflinkUnset {
		return xfsHasReflink == xfsReflinkSupport
	}

	// run mkfs.xfs in the same namespace as formatting would be done in
	// mountVolumeToStagePath()
	diskMounter := &mount.SafeFormatAndMount{Interface: ns.mounter, Exec: utilexec.New()}
	out, err := diskMounter.Exec.Command("mkfs.xfs").CombinedOutput()
	if err != nil {
		// mkfs.xfs should fail with an error message (and help text)
		if strings.Contains(string(out), "reflink=0|1") {
			xfsHasReflink = xfsReflinkSupport
			return true
		}
	}

	xfsHasReflink = xfsReflinkNoSupport
	return false
}

// NodeGetVolumeStats returns volume stats.
func (ns *NodeServer) NodeGetVolumeStats(ctx context.Context, req *csi.NodeGetVolumeStatsRequest) (*csi.NodeGetVolumeStatsResponse, error) {
	var err error
	targetPath := req.GetVolumePath()
	if targetPath == "" {
		err = fmt.Errorf("targetpath %v is empty", targetPath)
		return nil, status.Error(codes.InvalidArgument, err.Error())
	}

	stat, err := os.Stat(targetPath)
	if err != nil {
		return nil, status.Errorf(codes.InvalidArgument, "failed to get stat for targetpath %q: %v", targetPath, err)
	}

	if stat.Mode().IsDir() {
		return csicommon.FilesystemNodeGetVolumeStats(ctx, targetPath)
	} else if (stat.Mode() & os.ModeDevice) == os.ModeDevice {
		return blockNodeGetVolumeStats(ctx, targetPath)
	}

	return nil, fmt.Errorf("targetpath %q is not a block device", targetPath)
}

// blockNodeGetVolumeStats gets the metrics for a `volumeMode: Block` type of
// volume. At the moment, only the size of the block-device can be returned, as
// there are no secrets in the NodeGetVolumeStats request that enables us to
// connect to the Ceph cluster.
//
// TODO: https://github.com/container-storage-interface/spec/issues/371#issuecomment-756834471
func blockNodeGetVolumeStats(ctx context.Context, targetPath string) (*csi.NodeGetVolumeStatsResponse, error) {
	args := []string{"--noheadings", "--bytes", "--output=SIZE", targetPath}
	lsblkSize, _, err := util.ExecCommand(ctx, "/bin/lsblk", args...)
	if err != nil {
		err = fmt.Errorf("lsblk %v returned an error: %w", args, err)
		util.ErrorLog(ctx, err.Error())
		return nil, status.Error(codes.Internal, err.Error())
	}

	size, err := strconv.ParseInt(strings.TrimSpace(lsblkSize), 10, 64)
	if err != nil {
		err = fmt.Errorf("failed to convert %q to bytes: %w", lsblkSize, err)
		util.ErrorLog(ctx, err.Error())
		return nil, status.Error(codes.Internal, err.Error())
	}

	return &csi.NodeGetVolumeStatsResponse{
		Usage: []*csi.VolumeUsage{
			{
				Total: size,
				Unit:  csi.VolumeUsage_BYTES,
			},
		},
	}, nil
}