chore(refactor): move xfs and mount code out of zfs package

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

pkg/xfs/xfs_util.go

@@ -0,0 +1,112 @@
+/*
+Copyright 2020 The OpenEBS 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 xfs
+
+import (
+	"github.com/openebs/zfs-localpv/pkg/mount"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"strings"
+
+	"k8s.io/klog"
+)
+
+func xfsTempMount(device string) error {
+	pvol := strings.Split(device, "/")
+	volname := pvol[len(pvol)-1]
+
+	// evaluate the symlink to get the dev path for volume
+	dev, err := filepath.EvalSymlinks(device)
+	if err != nil {
+		return err
+	}
+
+	// create a temporary directory to mount the xfs file system
+	tmpdir := "/tmp/" + volname
+	err = os.Mkdir(tmpdir, 0755)
+	if os.IsNotExist(err) {
+		klog.Errorf("xfs: failed to create tmpdir %s error: %s", tmpdir, err.Error())
+		return err
+	}
+
+	/*
+	 * Device might have already mounted at the tmp path but umount might have failed
+	 * in previous attempt. Checking here if device is not mounted then only attempt
+	 * to mount it, otherwise proceed with the umount.
+	 */
+	curMounts, err := mount.GetMounts(dev)
+	if err != nil {
+		klog.Errorf("xfs: get mounts failed dev: %s err: %v", device, err.Error())
+		return err
+	} else if len(curMounts) == 0 {
+		// mount with nouuid, so that it can play the log
+		cmd := exec.Command("mount", "-o", "nouuid", device, tmpdir)
+		out, err := cmd.CombinedOutput()
+		if err != nil {
+			klog.Errorf("xfs: failed to mount device %s => %s error: %s", device, tmpdir, string(out))
+			return err
+		}
+	} else {
+		klog.Infof("xfs: device already mounted %s => [%v]", device, curMounts)
+	}
+
+	// log has been replayed, unmount the volume
+	cmd := exec.Command("umount", tmpdir)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		klog.Errorf("xfs: failed to umount tmpdir %s error: %s", tmpdir, string(out))
+		return err
+	}
+
+	// remove the tmp directory
+	err = os.Remove(tmpdir)
+	if err != nil {
+		// don't return error, reconciliation is not needed as umount is done
+		klog.Errorf("xfs: failed to remove tmpdir %s error: %s", tmpdir, err.Error())
+	}
+	return nil
+}
+
+/*
+* We have to generate a new UUID for the cloned volumes with xfs filesystem
+* otherwise system won't let anyone mount it if UUID is same. Here, since cloned
+* volume refers to the same block because of the way ZFS clone works, it will
+* also have the same UUID.
+* There might be something there in the xfs log, we have to clear them
+* so that filesystem is clean and we can generate the UUID for it.
+ */
+
+// GenerateUUID generates a new UUID for the given device
+func GenerateUUID(device string) error {
+	// temporary mount the volume with nouuid to replay the logs
+	err := xfsTempMount(device)
+	if err != nil {
+		return err
+	}
+
+	// for mounting the cloned volume for xfs, a new UUID has to be generated
+	cmd := exec.Command("xfs_admin", "-U", "generate", device)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		klog.Errorf("xfs: uuid generate failed for device %s error: %s", device, string(out))
+		return err
+	}
+	klog.Infof("xfs: generated UUID for the device %s \n %v", device, string(out))
+	return nil
+}