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Update Unstage transaction to undo steps done in Stage

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In unstage we now adhere to the transaction (or order of steps)
done in Stage. To enable this we stash the image meta data
into a local file on the staging path for use with unstage
request.

This helps in unmapping a stale map, in case the mount or
other steps in the transaction are complete.

Signed-off-by: ShyamsundarR <srangana@redhat.com>
This commit is contained in:
ShyamsundarR 2019-08-03 18:11:28 -04:00 committed by mergify[bot]
parent 44f7b1fe4b
commit 885ec7049d
4 changed files with 214 additions and 119 deletions
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9
pkg/rbd/errors.go
View File

@ -57,3 +57,12 @@ type ErrInvalidVolID struct {
func (e ErrInvalidVolID) Error() string {
return e.err.Error()
}
// ErrMissingStash is returned when the image metadata stash file is not found
type ErrMissingStash struct {
err error
}
func (e ErrMissingStash) Error() string {
return e.err.Error()
}

202
pkg/rbd/nodeserver.go
View File

@ -19,8 +19,6 @@ package rbd
import (
"fmt"
"os"
"os/exec"
"regexp"
"strings"
csicommon "github.com/ceph/ceph-csi/pkg/csi-common"
@ -45,9 +43,15 @@ type NodeServer struct {
// 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
// it is a file system
// - We stage the volume into a file, named after the VolumeID inside stagingTargetPath if it is
// a block volume
// 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)
func (ns *NodeServer) NodeStageVolume(ctx context.Context, req *csi.NodeStageVolumeRequest) (*csi.NodeStageVolumeResponse, error) {
if err := util.ValidateNodeStageVolumeRequest(req); err != nil {
return nil, err
@ -89,8 +93,8 @@ func (ns *NodeServer) NodeStageVolume(ctx context.Context, req *csi.NodeStageVol
isLegacyVolume = true
}
stagingTargetPath := req.GetStagingTargetPath()
stagingTargetPath += "/" + volID
stagingParentPath := req.GetStagingTargetPath()
stagingTargetPath := stagingParentPath + "/" + req.GetVolumeId()
idLk := nodeVolumeIDLocker.Lock(volID)
defer nodeVolumeIDLocker.Unlock(idLk, volID)
@ -113,22 +117,29 @@ func (ns *NodeServer) NodeStageVolume(ctx context.Context, req *csi.NodeStageVol
}
volOptions.RbdImageName = volName
isMounted := false
isStagePathCreated := false
devicePath := ""
// 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(stagingParentPath, devicePath, volID, isStagePathCreated, isMounted)
}
}()
// Mapping RBD image
devicePath, err := attachRBDImage(volOptions, cr)
devicePath, err = attachRBDImage(volOptions, cr)
if err != nil {
return nil, status.Error(codes.Internal, err.Error())
}
klog.V(4).Infof("rbd image: %s/%s was successfully mapped at %s\n", req.GetVolumeId(), volOptions.Pool, devicePath)
isMounted := false
isStagePathCreated := false
// if mounting to stagingpath fails unmap the rbd device. this wont leave any
// stale rbd device if unstage is not called
defer func() {
if err != nil {
ns.cleanupStagingPath(stagingTargetPath, devicePath, volID, isStagePathCreated, isMounted)
}
}()
err = ns.createStageMountPoint(stagingTargetPath, isBlock)
if err != nil {
return nil, status.Error(codes.Internal, err.Error())
@ -152,24 +163,40 @@ func (ns *NodeServer) NodeStageVolume(ctx context.Context, req *csi.NodeStageVol
return &csi.NodeStageVolumeResponse{}, nil
}
func (ns *NodeServer) cleanupStagingPath(stagingTargetPath, devicePath, volID string, isStagePathCreated, isMounted bool) {
func (ns *NodeServer) undoStagingTransaction(stagingParentPath, devicePath, volID string, isStagePathCreated, isMounted bool) {
var err error
stagingTargetPath := stagingParentPath + "/" + volID
if isMounted {
err = ns.mounter.Unmount(stagingTargetPath)
if err != nil {
klog.Errorf("failed to unmount stagingtargetPath: %s with error: %v", stagingTargetPath, err)
return
}
}
// remove the block file created on staging path
// remove the file/directory created on staging path
if isStagePathCreated {
err = os.Remove(stagingTargetPath)
if err != nil {
klog.Errorf("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
}
}
// Unmapping rbd device
if err = detachRBDDevice(devicePath); err != nil {
klog.Errorf("failed to unmap rbd device: %s for volume %s with error: %v", devicePath, volID, err)
if devicePath != "" {
err = detachRBDDevice(devicePath)
if err != nil {
klog.Errorf("failed to unmap rbd device: %s for volume %s with error: %v", 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(stagingParentPath); err != nil {
klog.Errorf("failed to cleanup image metadata stash (%v)", err)
return
}
}
@ -190,8 +217,10 @@ func (ns *NodeServer) createStageMountPoint(mountPath string, isBlock bool) erro
err := os.Mkdir(mountPath, 0750)
if err != nil {
klog.Errorf("failed to create mountPath:%s with error: %v", mountPath, err)
return status.Error(codes.Internal, err.Error())
if !os.IsExist(err) {
klog.Errorf("failed to create mountPath:%s with error: %v", mountPath, err)
return status.Error(codes.Internal, err.Error())
}
}
return nil
@ -372,7 +401,7 @@ func (ns *NodeServer) NodeUnpublishVolume(ctx context.Context, req *csi.NodeUnpu
return nil, status.Error(codes.Internal, err.Error())
}
klog.Infof("rbd: successfully unbinded volume %s from %s", req.GetVolumeId(), targetPath)
klog.Infof("rbd: successfully unbound volume %s from %s", req.GetVolumeId(), targetPath)
return &csi.NodeUnpublishVolumeResponse{}, nil
}
@ -384,111 +413,72 @@ func (ns *NodeServer) NodeUnstageVolume(ctx context.Context, req *csi.NodeUnstag
return nil, err
}
stagingTargetPath := req.GetStagingTargetPath()
stagingTargetPath += "/" + req.GetVolumeId()
stagingParentPath := req.GetStagingTargetPath()
stagingTargetPath := stagingParentPath + "/" + req.GetVolumeId()
notMnt, err := mount.IsNotMountPoint(ns.mounter, stagingTargetPath)
if err != nil {
if os.IsNotExist(err) {
// staging targetPath has already been deleted
klog.V(4).Infof("stagingTargetPath: %s has already been deleted", stagingTargetPath)
return &csi.NodeUnstageVolumeResponse{}, nil
if !os.IsNotExist(err) {
return nil, status.Error(codes.NotFound, err.Error())
}
return nil, status.Error(codes.NotFound, err.Error())
// Continue on ENOENT errors as we may still have the image mapped
notMnt = true
}
if notMnt {
// TODO: IsNotExist error should have been caught above
if err = os.Remove(stagingTargetPath); err != nil {
if !notMnt {
// Unmounting the image
err = ns.mounter.Unmount(stagingTargetPath)
if err != nil {
klog.V(3).Infof("failed to unmount targetPath: %s with error: %v", stagingTargetPath, err)
return nil, status.Error(codes.Internal, err.Error())
}
return &csi.NodeUnstageVolumeResponse{}, nil
}
// Unmount the volume
devicePath, cnt, err := mount.GetDeviceNameFromMount(ns.mounter, stagingTargetPath)
if err != nil {
return nil, status.Error(codes.Internal, err.Error())
}
if err = ns.unmount(stagingTargetPath, devicePath, cnt); err != nil {
return nil, err
}
if err = os.Remove(stagingTargetPath); err != nil {
return nil, status.Error(codes.Internal, err.Error())
}
klog.Infof("rbd: successfully unmounted volume %s from %s", req.GetVolumeId(), stagingTargetPath)
return &csi.NodeUnstageVolumeResponse{}, nil
}
func (ns *NodeServer) unmount(targetPath, devicePath string, cnt int) error {
var err error
// Bind mounted device needs to be resolved by using resolveBindMountedBlockDevice
if devicePath == "devtmpfs" {
devicePath, err = resolveBindMountedBlockDevice(targetPath)
if err != nil {
return status.Error(codes.Internal, err.Error())
// 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) {
klog.Errorf("failed to remove staging target path (%s): (%v)", stagingTargetPath, err)
return nil, status.Error(codes.Internal, err.Error())
}
klog.V(4).Infof("NodeUnpublishVolume: devicePath: %s, (original)cnt: %d\n", devicePath, cnt)
// cnt for GetDeviceNameFromMount is broken for bind mouted device,
// it counts total number of mounted "devtmpfs", instead of counting this device.
// So, forcibly setting cnt to 1 here.
// TODO : fix this properly
cnt = 1
}
klog.V(4).Infof("NodeUnpublishVolume: targetPath: %s, devicePath: %s\n", targetPath, devicePath)
// Unmounting the image
err = ns.mounter.Unmount(targetPath)
imgInfo, err := lookupRBDImageMetadataStash(stagingParentPath)
if err != nil {
klog.V(3).Infof("failed to unmount targetPath: %s with error: %v", targetPath, err)
return status.Error(codes.Internal, err.Error())
}
klog.V(2).Infof("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())
}
cnt--
if cnt != 0 {
// TODO should this be fixed not to success, so that driver can retry unmounting?
return nil
// If not mounted, and error is anything other than metadata file missing, it is an error
if _, ok := err.(ErrMissingStash); !ok {
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
if err = detachRBDDevice(devicePath); err != nil {
klog.V(3).Infof("failed to unmap rbd device: %s with error: %v", devicePath, err)
return status.Error(codes.Internal, err.Error())
imageSpec := imgInfo.Pool + "/" + imgInfo.ImageName
if err = detachRBDImageOrDeviceSpec(imageSpec, true, imgInfo.NbdAccess); err != nil {
klog.Errorf("error unmapping volume (%s) from staging path (%s): (%v)",
req.GetVolumeId(), stagingTargetPath, err)
return nil, status.Error(codes.Internal, err.Error())
}
return nil
}
func resolveBindMountedBlockDevice(mountPath string) (string, error) {
// #nosec
cmd := exec.Command("findmnt", "-n", "-o", "SOURCE", "--first-only", "--target", mountPath)
out, err := cmd.CombinedOutput()
if err != nil {
klog.V(2).Infof("Failed findmnt command for path %s: %s %v", mountPath, out, err)
return "", err
}
return parseFindMntResolveSource(string(out))
}
klog.Infof("successfully unmounted volume (%s) from staging path (%s)",
req.GetVolumeId(), stagingTargetPath)
// parse output of "findmnt -o SOURCE --first-only --target" and return just the SOURCE
func parseFindMntResolveSource(out string) (string, error) {
// cut trailing newline
out = strings.TrimSuffix(out, "\n")
// Check if out is a mounted device
reMnt := regexp.MustCompile("^(/[^/]+(?:/[^/]*)*)$")
if match := reMnt.FindStringSubmatch(out); match != nil {
return match[1], nil
if err = cleanupRBDImageMetadataStash(stagingParentPath); err != nil {
klog.Errorf("failed to cleanup image metadata stash (%v)", err)
return nil, status.Error(codes.Internal, err.Error())
}
// Check if out is a block device
// nolint
reBlk := regexp.MustCompile("^devtmpfs\\[(/[^/]+(?:/[^/]*)*)\\]$")
if match := reBlk.FindStringSubmatch(out); match != nil {
return fmt.Sprintf("/dev%s", match[1]), nil
}
return "", fmt.Errorf("parseFindMntResolveSource: %s doesn't match to any expected findMnt output", out)
return &csi.NodeUnstageVolumeResponse{}, nil
}
// NodeGetCapabilities returns the supported capabilities of the node server

46
pkg/rbd/rbd_attach.go
View File

@ -37,6 +37,13 @@ const (
accessTypeNbd = "nbd"
rbd = "rbd"
// Output strings returned during invocation of "rbd unmap --device-type... <imageSpec>" when
// image is not found to be mapped. Used to ignore errors when attempting to unmap such images.
// The %s format specifier should contain the <imageSpec> string
// NOTE: When using devicePath instead of imageSpec, the error strings are different
rbdUnmapCmdkRbdMissingMap = "rbd: %s: not a mapped image or snapshot"
rbdUnmapCmdNbdMissingMap = "rbd-nbd: %s is not mapped"
)
var hasNBD = false
@ -195,23 +202,18 @@ func createPath(volOpt *rbdVolume, cr *util.Credentials) (string, error) {
mapOptions := []string{
"--id", cr.ID,
"-m", volOpt.Monitors,
"--keyfile=" + cr.KeyFile}
// Construct map and unmap variants for the command
mapOptions = append(mapOptions, "map", imagePath)
unmapOptions := []string{"unmap", imagePath}
"--keyfile=" + cr.KeyFile,
"map", imagePath,
}
// Choose access protocol
useNBD := false
accessType := accessTypeKRbd
if volOpt.Mounter == rbdTonbd && hasNBD {
accessType = accessTypeNbd
useNBD = true
}
// Update options with device type selection
mapOptions = append(mapOptions, "--device-type", accessType)
unmapOptions = append(unmapOptions, "--device-type", accessType)
// Execute map
output, err := execCommand(rbd, mapOptions)
@ -248,20 +250,38 @@ func waitForrbdImage(backoff wait.Backoff, volOptions *rbdVolume, cr *util.Crede
}
func detachRBDDevice(devicePath string) error {
nbdType := false
if strings.HasPrefix(devicePath, "/dev/nbd") {
nbdType = true
}
return detachRBDImageOrDeviceSpec(devicePath, false, nbdType)
}
// detachRBDImageOrDeviceSpec detaches an rbd imageSpec or devicePath, with additional checking
// when imageSpec is used to decide if image is already unmapped
func detachRBDImageOrDeviceSpec(imageOrDeviceSpec string, isImageSpec, ndbType bool) error {
var err error
var output []byte
klog.V(3).Infof("rbd: unmap device %s", devicePath)
accessType := accessTypeKRbd
if strings.HasPrefix(devicePath, "/dev/nbd") {
if ndbType {
accessType = accessTypeNbd
}
options := []string{"unmap", "--device-type", accessType, devicePath}
options := []string{"unmap", "--device-type", accessType, imageOrDeviceSpec}
output, err = execCommand(rbd, options)
if err != nil {
return fmt.Errorf("rbd: unmap failed %v, rbd output: %s", err, string(output))
// Messages for krbd and nbd differ, hence checking either of them for missing mapping
// This is not applicable when a device path is passed in
if isImageSpec &&
(strings.Contains(string(output), fmt.Sprintf(rbdUnmapCmdkRbdMissingMap, imageOrDeviceSpec)) ||
strings.Contains(string(output), fmt.Sprintf(rbdUnmapCmdNbdMissingMap, imageOrDeviceSpec))) {
// Devices found not to be mapped are treated as a successful detach
klog.Infof("image or device spec (%s) not mapped", imageOrDeviceSpec)
return nil
}
return fmt.Errorf("rbd: unmap for spec (%s) failed (%v): (%s)", imageOrDeviceSpec, err, string(output))
}
return nil

76
pkg/rbd/rbd_util.go
View File

@ -19,7 +19,10 @@ package rbd
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"strings"
"time"
@ -704,3 +707,76 @@ func getSnapInfo(monitors string, cr *util.Credentials, poolName, imageName, sna
return snpInfo, ErrSnapNotFound{snapName, fmt.Errorf("snap (%s) for image (%s) not found",
snapName, poolName+"/"+imageName)}
}
// rbdImageMetadataStash strongly typed JSON spec for stashed RBD image metadata
type rbdImageMetadataStash struct {
Version int `json:"Version"`
Pool string `json:"pool"`
ImageName string `json:"image"`
NbdAccess bool `json:"accessType"`
}
// file name in which image metadata is stashed
const stashFileName = "image-meta.json"
// stashRBDImageMetadata stashes required fields into the stashFileName at the passed in path, in
// JSON format
func stashRBDImageMetadata(volOptions *rbdVolume, path string) error {
var imgMeta = rbdImageMetadataStash{
Version: 1, // Stash a v1 for now, in case of changes later, there are no checks for this at present
Pool: volOptions.Pool,
ImageName: volOptions.RbdImageName,
}
imgMeta.NbdAccess = false
if volOptions.Mounter == rbdTonbd && hasNBD {
imgMeta.NbdAccess = true
}
encodedBytes, err := json.Marshal(imgMeta)
if err != nil {
return fmt.Errorf("failed to marshall JSON image metadata for image (%s) in pool (%s): (%v)",
volOptions.RbdImageName, volOptions.Pool, err)
}
fPath := filepath.Join(path, stashFileName)
err = ioutil.WriteFile(fPath, encodedBytes, 0600)
if err != nil {
return fmt.Errorf("failed to stash JSON image metadata for image (%s) in pool (%s) at path (%s): (%v)",
volOptions.RbdImageName, volOptions.Pool, fPath, err)
}
return nil
}
// lookupRBDImageMetadataStash reads and returns stashed image metadata at passed in path
func lookupRBDImageMetadataStash(path string) (rbdImageMetadataStash, error) {
var imgMeta rbdImageMetadataStash
fPath := filepath.Join(path, stashFileName)
encodedBytes, err := ioutil.ReadFile(fPath)
if err != nil {
if !os.IsNotExist(err) {
return imgMeta, fmt.Errorf("failed to read stashed JSON image metadata from path (%s): (%v)", fPath, err)
}
return imgMeta, ErrMissingStash{err}
}
err = json.Unmarshal(encodedBytes, &imgMeta)
if err != nil {
return imgMeta, fmt.Errorf("failed to unmarshall stashed JSON image metadata from path (%s): (%v)", fPath, err)
}
return imgMeta, nil
}
// cleanupRBDImageMetadataStash cleans up any stashed metadata at passed in path
func cleanupRBDImageMetadataStash(path string) error {
fPath := filepath.Join(path, stashFileName)
if err := os.Remove(fPath); err != nil {
return fmt.Errorf("failed to cleanup stashed JSON data (%s): (%v)", fPath, err)
}
return nil
}