fix(xfs): clearing the xfs log before generating UUID

pkg/zfs/xfs_util.go

@@ -0,0 +1,90 @@
+/*
+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 zfs
+
+import (
+	"os"
+	"os/exec"
+
+	"github.com/Sirupsen/logrus"
+	"strings"
+)
+
+func xfs_temp_mount(volume string) error {
+	device := ZFS_DEVPATH + volume
+	pvol := strings.Split(volume, "/")
+
+	// create a temporary directory to mount the xfs file system
+	tmpdir := "/tmp/" + pvol[1]
+	err := os.Mkdir(tmpdir, 0755)
+	if err != nil {
+		logrus.Errorf("xfs: failed to create tmpdir %s error: %s", tmpdir, err.Error())
+		return err
+	}
+
+	// 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 {
+		logrus.Errorf("xfs: failed to mount volume %s=>%s error: %s", device, tmpdir, string(out))
+		return err
+	}
+
+	// log has been replayed, unmount the volume
+	cmd = exec.Command("umount", tmpdir)
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		logrus.Errorf("xfs: failed to umount tmpdir %s error: %s", tmpdir, string(out))
+		return err
+	}
+
+	// remove the directory
+	err = os.Remove(tmpdir)
+	if err != nil {
+		logrus.Errorf("xfs: failed to remove tmpdir %s error: %s", tmpdir, err.Error())
+		return err
+	}
+	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.
+ */
+func xfs_generate_uuid(volume string) error {
+	device := ZFS_DEVPATH + volume
+
+	// temporary mount the volume with nouuid to replay the logs
+	err := xfs_temp_mount(volume)
+	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 {
+		logrus.Errorf("xfs: uuid generate failed %s error: %s", volume, string(out))
+		return err
+	}
+	logrus.Infof("xfs: generated UUID for the cloned volume %s \n %v", volume, string(out))
+	return nil
+}

pkg/zfs/zfs_util.go

@@ -362,14 +362,7 @@ func CreateClone(vol *apis.ZFSVolume) error {
 	}
 
 	if vol.Spec.FsType == "xfs" {
-		// for mounting the cloned volume for xfs, a new UUID has to be generated
-		device := ZFS_DEVPATH + volume
-		cmd := exec.Command("xfs_admin", "-U", "generate", device)
-		out, err := cmd.CombinedOutput()
-		if err != nil {
-			logrus.Errorf("zfspv: Clone XFS uuid generate failed error: %s", string(out))
-			return err
-		}
+		return xfs_generate_uuid(volume)
 	}
 	return nil
 }