Enable errcheck linter and resolve found issues.

Signed-off-by: Xun Jiang <blackpiglet@gmail.com>

pkg/controller/backup_controller.go

@@ -561,8 +561,7 @@ func (b *backupReconciler) validateAndGetSnapshotLocations(backup *velerov1api.B
 				continue
 			}
 			location := &velerov1api.VolumeSnapshotLocation{}
-			b.kbClient.Get(context.Background(), kbclient.ObjectKey{Namespace: backup.Namespace, Name: defaultLocation}, location)
-			if err != nil {
+			if err := b.kbClient.Get(context.Background(), kbclient.ObjectKey{Namespace: backup.Namespace, Name: defaultLocation}, location); err != nil {
 				errors = append(errors, fmt.Sprintf("error getting volume snapshot location named %s: %v", defaultLocation, err))
 				continue
 			}

pkg/controller/backup_repository_controller.go

@@ -96,7 +96,9 @@ func (r *BackupRepoReconciler) invalidateBackupReposForBSL(bslObj client.Object)
 
 	for i := range list.Items {
 		r.logger.WithField("BSL", bsl.Name).Infof("Invalidating Backup Repository %s", list.Items[i].Name)
-		r.patchBackupRepository(context.Background(), &list.Items[i], repoNotReady("re-establish on BSL change"))
+		if err := r.patchBackupRepository(context.Background(), &list.Items[i], repoNotReady("re-establish on BSL change")); err != nil {
+			r.logger.WithField("BSL", bsl.Name).WithError(err).Errorf("fail to patch BackupRepository %s", list.Items[i].Name)
+		}
 	}
 
 	return []reconcile.Request{}

pkg/controller/backup_sync_controller.go

@@ -18,6 +18,7 @@ package controller
 
 import (
 	"context"
+	"fmt"
 	"time"
 
 	snapshotv1api "github.com/kubernetes-csi/external-snapshotter/client/v4/apis/volumesnapshot/v1"
@@ -397,7 +398,10 @@ func backupSyncSourceOrderFunc(objList client.ObjectList) client.ObjectList {
 				cpBsl := bsl
 				bslArray = append(bslArray, &cpBsl)
 			}
-			meta.SetList(resultBSLList, bslArray)
+			if err := meta.SetList(resultBSLList, bslArray); err != nil {
+				fmt.Printf("fail to sort BSL list: %s", err.Error())
+				return &velerov1api.BackupStorageLocationList{}
+			}
 
 			return resultBSLList
 		}

pkg/controller/restore_controller.go

@@ -305,10 +305,7 @@ func (r *restoreReconciler) validateAndComplete(restore *api.Restore) backupInfo
 		}))
 
 		backupList := &api.BackupList{}
-		r.kbClient.List(context.Background(), backupList, &client.ListOptions{
-			LabelSelector: selector,
-		})
-		if err != nil {
+		if err := r.kbClient.List(context.Background(), backupList, &client.ListOptions{LabelSelector: selector}); err != nil {
 			restore.Status.ValidationErrors = append(restore.Status.ValidationErrors, "Unable to list backups for schedule")
 			return backupInfo{}
 		}