From aaa080a520dfc119e73bfb4710c4192064c56088 Mon Sep 17 00:00:00 2001
From: Santosh Pillai <sapillai@redhat.com>
Date: Mon, 18 Apr 2022 15:38:09 +0530
Subject: [PATCH] feat: create thin pool

Signed-off-by: Santosh Pillai <sapillai@redhat.com>
---
 pkg/vgmanager/lvm.go                  | 42 +++++++++++++++++++
 pkg/vgmanager/vgmanager_controller.go | 59 +++++++++++++++++++++++----
 2 files changed, 94 insertions(+), 7 deletions(-)

diff --git a/pkg/vgmanager/lvm.go b/pkg/vgmanager/lvm.go
index 765c35175..b3a9917d3 100644
--- a/pkg/vgmanager/lvm.go
+++ b/pkg/vgmanager/lvm.go
@@ -37,6 +37,7 @@ const (
 	vgExtendCmd = "/usr/sbin/vgextend"
 	vgRemoveCmd = "/usr/sbin/vgremove"
 	pvRemoveCmd = "/usr/sbin/pvremove"
+	lvCreateCmd = "/usr/sbin/lvcreate"
 )
 
 // vgsOutput represents the output of the `vgs --reportformat json` command
@@ -58,6 +59,18 @@ type pvsOutput struct {
 	} `json:"report"`
 }
 
+// lvsOutput represents the output of the `lvs --reportformat json` command
+type lvsOutput struct {
+	Report []struct {
+		Lv []struct {
+			Name     string `json:"lv_name"`
+			VgName   string `json:"vg_name"`
+			PoolName string `json:"pool_lv"`
+			LvAttr   string `json:"lv_attr"`
+		} `json:"pv"`
+	} `json:"report"`
+}
+
 // VolumeGroup represents a volume group of linux lvm.
 type VolumeGroup struct {
 	// Name is the name of the volume group
@@ -214,6 +227,35 @@ func ListVolumeGroups(exec internal.Executor) ([]VolumeGroup, error) {
 	return vgList, nil
 }
 
+// ListLogicalVolumes returns list of logical volumes for a volume group
+func ListLogicalVolumes(exec internal.Executor, vgName string) ([]string, error) {
+	res, err := GetLVSOutput(exec, vgName)
+	if err != nil {
+		return []string{}, err
+	}
+
+	lvs := []string{}
+	for _, report := range res.Report {
+		for _, lv := range report.Lv {
+			lvs = append(lvs, lv.Name)
+		}
+	}
+	return lvs, nil
+}
+
+// GetLVSOutput returns the output for `lvs` command in json format
+func GetLVSOutput(exec internal.Executor, vgName string) (*lvsOutput, error) {
+	res := new(lvsOutput)
+	args := []string{
+		"lvs", "-S", fmt.Sprintf("vgname=%s", vgName), "--reportformat", "json",
+	}
+	if err := execute(exec, res, args...); err != nil {
+		return nil, err
+	}
+
+	return res, nil
+}
+
 func execute(exec internal.Executor, v interface{}, args ...string) error {
 	output, err := exec.ExecuteCommandWithOutputAsHost(lvmCmd, args...)
 	if err != nil {
diff --git a/pkg/vgmanager/vgmanager_controller.go b/pkg/vgmanager/vgmanager_controller.go
index 495db61cb..ac667c582 100644
--- a/pkg/vgmanager/vgmanager_controller.go
+++ b/pkg/vgmanager/vgmanager_controller.go
@@ -20,6 +20,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/go-logr/logr"
@@ -43,7 +44,8 @@ import (
 )
 
 const (
-	ControllerName = "vg-manager"
+	ControllerName   = "vg-manager"
+	DefaultChunkSize = "512"
 )
 
 // SetupWithManager sets up the controller with the Manager.
@@ -188,16 +190,30 @@ func (r *VGReconciler) reconcile(ctx context.Context, req ctrl.Request, volumeGr
 	}
 
 	if !found {
-		lvmdConfig.DeviceClasses = append(lvmdConfig.DeviceClasses, &lvmd.DeviceClass{
-			Name:        volumeGroup.Name,
-			VolumeGroup: volumeGroup.Name,
-			Default:     true,
-		})
+		dc := &lvmd.DeviceClass{
+			Name:           volumeGroup.Name,
+			VolumeGroup:    volumeGroup.Name,
+			Default:        true,
+			ThinPoolConfig: &lvmd.ThinPoolConfig{},
+		}
+
+		if volumeGroup.Spec.ThinPoolConfig != nil {
+			dc.Type = lvmd.TypeThin
+			dc.ThinPoolConfig.Name = volumeGroup.Spec.ThinPoolConfig.Name
+			dc.ThinPoolConfig.OverprovisionRatio = float64(volumeGroup.Spec.ThinPoolConfig.OverprovisionRatio)
+		}
+
+		lvmdConfig.DeviceClasses = append(lvmdConfig.DeviceClasses, dc)
+	}
+
+	// Create thin pool
+	err = r.addThinPoolToVG(volumeGroup.Name, volumeGroup.Spec.ThinPoolConfig)
+	if err != nil {
+		r.Log.Error(err, "failed to create thin pool", "VGName", "ThinPool", volumeGroup.Name, volumeGroup.Spec.ThinPoolConfig.Name)
 	}
 
 	// apply and save lvmconfig
 	// pass config to configChannel only if config has changed
-
 	if !cmp.Equal(existingLvmdConfig, lvmdConfig) {
 		err := saveLVMDConfig(lvmdConfig)
 		if err != nil {
@@ -224,6 +240,35 @@ func (r *VGReconciler) reconcile(ctx context.Context, req ctrl.Request, volumeGr
 	return ctrl.Result{RequeueAfter: requeueAfter}, nil
 }
 
+func (r *VGReconciler) addThinPoolToVG(vgName string, config *lvmv1alpha1.ThinPoolConfig) error {
+	resp, err := GetLVSOutput(r.executor, vgName)
+	if err != nil {
+		return fmt.Errorf("failed to list logical volumes in the volume group %q. %v", vgName, err)
+	}
+
+	for _, report := range resp.Report {
+		for _, lv := range report.Lv {
+			if lv.Name == config.Name {
+				if strings.Contains(lv.LvAttr, "t") {
+					r.Log.Info("lvm thinpool already exists", "VGName", vgName, "ThinPool", config.Name)
+					return nil
+				}
+
+				return fmt.Errorf("failed to create thin pool %q. Logical volume with same name already exists", config.Name)
+			}
+		}
+	}
+
+	args := []string{"-l", fmt.Sprintf("%d%%FREE", config.SizePercent), "-c", DefaultChunkSize, "-T", fmt.Sprintf("%s/%s", vgName, config.Name)}
+
+	_, err = r.executor.ExecuteCommandWithOutputAsHost(lvCreateCmd, args...)
+	if err != nil {
+		return fmt.Errorf("failed to create thin pool %q in the volume group %q. %v", config.Name, vgName, err)
+	}
+
+	return nil
+}
+
 func (r *VGReconciler) processDelete(ctx context.Context, volumeGroup *lvmv1alpha1.LVMVolumeGroup) error {
 
 	// Read the lvmd config file