lxd/storage/drivers: Fix linter errors

Signed-off-by: Wesley Hershberger <wesley.hershberger@canonical.com>

lxd/storage/drivers/driver_lvm.go

@@ -503,6 +503,8 @@ func (d *lvm) Delete(op *operations.Operation) error {
 	return nil
 }
 
+// Validate checks that all provide keys are supported and that no conflicting
+// or missing configuration is present.
 func (d *lvm) Validate(config map[string]string) error {
 	rules := map[string]func(value string) error{
 		"size": validate.Optional(validate.IsSize),

lxd/storage/drivers/driver_zfs.go

@@ -623,6 +623,7 @@ func (d *zfs) Unmount() (bool, error) {
 	return true, nil
 }
 
+// GetResources returns utilization statistics for the storage pool.
 func (d *zfs) GetResources() (*api.ResourcesStoragePool, error) {
 	// Get the total amount of space.
 	availableStr, err := d.getDatasetProperty(d.config["zfs.pool_name"], "available")
@@ -655,7 +656,8 @@ func (d *zfs) GetResources() (*api.ResourcesStoragePool, error) {
 	return &res, nil
 }
 
-// MigrationType returns the type of transfer methods to be used when doing migrations between pools in preference order.
+// MigrationTypes returns the type of transfer methods to be used when doing
+// migrations between pools in preference order.
 func (d *zfs) MigrationTypes(contentType ContentType, refresh bool, copySnapshots bool) []migration.Type {
 	var rsyncFeatures []string
 

lxd/storage/drivers/driver_zfs_volumes.go

@@ -1024,7 +1024,7 @@ func (d *zfs) CreateVolumeFromMigration(vol VolumeCopy, conn io.ReadWriteCloser,
 			return fmt.Errorf("Failed sending ZFS migration header: %w", err)
 		}
 
-		err = conn.Close() //End the frame.
+		err = conn.Close() // End the frame.
 		if err != nil {
 			return fmt.Errorf("Failed closing ZFS migration header frame: %w", err)
 		}
@@ -2517,7 +2517,7 @@ func (d *zfs) MigrateVolume(vol VolumeCopy, conn io.ReadWriteCloser, volSrcArgs
 			return fmt.Errorf("Failed sending ZFS migration header: %w", err)
 		}
 
-		err = conn.Close() //End the frame.
+		err = conn.Close() // End the frame.
 		if err != nil {
 			return fmt.Errorf("Failed closing ZFS migration header frame: %w", err)
 		}
@@ -3187,7 +3187,7 @@ func (d *zfs) mountVolumeSnapshot(snapVol Volume, snapshotDataset string, mountP
 	return cleanup, nil
 }
 
-// UnmountVolume simulates unmounting a volume snapshot.
+// UnmountVolumeSnapshot simulates unmounting a volume snapshot.
 func (d *zfs) UnmountVolumeSnapshot(snapVol Volume, op *operations.Operation) (bool, error) {
 	unlock, err := snapVol.MountLock()
 	if err != nil {

lxd/storage/drivers/utils.go

@@ -819,18 +819,20 @@ func loopFileSizeDefault() (uint64, error) {
 // It tries to enable direct I/O if supported.
 func loopDeviceSetup(sourcePath string) (string, error) {
 	out, err := shared.RunCommand("losetup", "--find", "--nooverlap", "--direct-io=on", "--show", sourcePath)
-	if err != nil {
-		if strings.Contains(err.Error(), "direct io") || strings.Contains(err.Error(), "Invalid argument") {
-			out, err = shared.RunCommand("losetup", "--find", "--nooverlap", "--show", sourcePath)
-			if err != nil {
-				return "", err
-			}
-		} else {
-			return "", err
-		}
+	if err == nil {
+		return strings.TrimSpace(out), nil
+	}
+
+	if !(strings.Contains(err.Error(), "direct io") || strings.Contains(err.Error(), "Invalid argument")) {
+		return "", err
+	}
+
+	out, err = shared.RunCommand("losetup", "--find", "--nooverlap", "--show", sourcePath)
+	if err == nil {
+		return strings.TrimSpace(out), nil
 	}
 
-	return strings.TrimSpace(out), nil
+	return "", err
 }
 
 // loopFileAutoDetach enables auto detach mode for a loop device.