feat(zfs-localpv): initial commit

provisioning and deprovisioning of
the volumes on the node where zfs pool
has already been setup. Pool name and the volume
parameters has to be given in storage class
which will be used to provision the volume.

Signed-off-by: Pawan <pawan@mayadata.io>

pkg/zfs/mount.go

@@ -0,0 +1,145 @@
+package zfs
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/Sirupsen/logrus"
+	apis "github.com/openebs/zfs-localpv/pkg/apis/openebs.io/core/v1alpha1"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"k8s.io/kubernetes/pkg/util/mount"
+)
+
+// FormatAndMountZvol formats and mounts the created volume to the desired mount path
+func FormatAndMountZvol(devicePath string, mountInfo *apis.MountInfo) error {
+	mounter := &mount.SafeFormatAndMount{Interface: mount.New(""), Exec: mount.NewOsExec()}
+
+	err := mounter.FormatAndMount(devicePath, mountInfo.MountPath, mountInfo.FSType, mountInfo.MountOptions)
+	if err != nil {
+		logrus.Errorf(
+			"zfspv: failed to mount volume %s [%s] to %s, error %v",
+			devicePath, mountInfo.FSType, mountInfo.MountPath, err,
+		)
+		return err
+	}
+
+	logrus.Infof("created zvol %v and mounted %v fs %v", devicePath, mountInfo.MountPath, mountInfo.FSType)
+	return nil
+}
+
+// UmountVolume unmounts the volume and the corresponding mount path is removed
+func UmountVolume(vol *apis.ZFSVolume, targetPath string,
+) error {
+	mounter := &mount.SafeFormatAndMount{Interface: mount.New(""), Exec: mount.NewOsExec()}
+
+	_, _, err := mount.GetDeviceNameFromMount(mounter, targetPath)
+	if err != nil {
+		logrus.Errorf(
+			"zfspv umount volume: failed to get device from mnt: %s\nError: %v",
+			targetPath, err,
+		)
+		return err
+	}
+
+	if pathExists, pathErr := mount.PathExists(targetPath); pathErr != nil {
+		return fmt.Errorf("Error checking if path exists: %v", pathErr)
+	} else if !pathExists {
+		logrus.Warningf(
+			"Warning: Unmount skipped because path does not exist: %v",
+			targetPath,
+		)
+		return nil
+	}
+
+	if err = mounter.Unmount(targetPath); err != nil {
+		logrus.Errorf(
+			"zfspv umount volume: failed to unmount: %s\nError: %v",
+			targetPath, err,
+		)
+		return err
+	}
+
+	if err := os.RemoveAll(targetPath); err != nil {
+		logrus.Errorf("zfspv: failed to remove mount path Error: %v", err)
+		return err
+	}
+
+	logrus.Infof("umount done path %v", targetPath)
+
+	return nil
+}
+
+// GetMounts gets mountpoints for the specified volume
+func GetMounts(devicepath string) ([]string, error) {
+
+	var (
+		currentMounts []string
+		err           error
+		mountList     []mount.MountPoint
+	)
+
+	dev, err := filepath.EvalSymlinks(devicepath)
+	if err != nil {
+		return nil, err
+	}
+	mounter := mount.New("")
+	// Get list of mounted paths present with the node
+	if mountList, err = mounter.List(); err != nil {
+		return nil, err
+	}
+	for _, mntInfo := range mountList {
+		if mntInfo.Device == dev {
+			currentMounts = append(currentMounts, mntInfo.Path)
+		}
+	}
+	return currentMounts, nil
+}
+
+// CreateAndMountZvol creates the zfs Volume
+// and mounts the disk to the specified path
+func CreateAndMountZvol(vol *apis.ZFSVolume, mount *apis.MountInfo) error {
+	if len(mount.MountPath) == 0 {
+		return status.Error(codes.InvalidArgument, "mount path missing in request")
+	}
+
+	if len(vol.Spec.OwnerNodeID) > 0 &&
+		vol.Spec.OwnerNodeID != NodeID {
+		return status.Error(codes.Internal, "volume is owned by different node")
+	}
+
+	devicePath, err := createZvol(vol)
+	if err != nil {
+		return status.Error(codes.Internal, err.Error())
+	}
+
+	err = UpdateZvolInfo(vol)
+	if err != nil {
+		return status.Error(codes.Internal, err.Error())
+	}
+
+	/*
+	 * This check is the famous *Wall Of North*
+	 * It will not let the volume to be mounted
+	 * at more than two places. The volume should
+	 * be unmounted before proceeding to the mount
+	 * operation.
+	 */
+	currentMounts, err := GetMounts(devicePath)
+	if err != nil {
+		return err
+	} else if len(currentMounts) >= 1 {
+		logrus.Errorf(
+			"can not mount, more than one mounts for volume:%s dev %s mounts: %v",
+			vol.Name, devicePath, currentMounts,
+		)
+		return status.Error(codes.Internal, "device already mounted")
+	}
+	err = FormatAndMountZvol(devicePath, mount)
+	if err != nil {
+		return status.Error(codes.Internal, err.Error())
+	}
+
+	return err
+}