Use errgroups instead of sync.WaitGroup as needed (#8354)

cmd/xl-v1-metadata.go

@@ -24,11 +24,11 @@ import (
 	"net/http"
 	"path"
 	"sort"
-	"sync"
 	"time"
 
 	xhttp "github.com/minio/minio/cmd/http"
 	"github.com/minio/minio/cmd/logger"
+	"github.com/minio/minio/pkg/sync/errgroup"
 	"github.com/minio/sha256-simd"
 )
 
@@ -452,31 +452,23 @@ func renameXLMetadata(ctx context.Context, disks []StorageAPI, srcBucket, srcEnt
 
 // writeUniqueXLMetadata - writes unique `xl.json` content for each disk in order.
 func writeUniqueXLMetadata(ctx context.Context, disks []StorageAPI, bucket, prefix string, xlMetas []xlMetaV1, quorum int) ([]StorageAPI, error) {
-	var wg sync.WaitGroup
-	var mErrs = make([]error, len(disks))
+	g := errgroup.WithNErrs(len(disks))
 
 	// Start writing `xl.json` to all disks in parallel.
-	for index, disk := range disks {
-		if disk == nil {
-			mErrs[index] = errDiskNotFound
-			continue
-		}
-		wg.Add(1)
-
-		// Pick one xlMeta for a disk at index.
-		xlMetas[index].Erasure.Index = index + 1
-
-		// Write `xl.json` in a routine.
-		go func(index int, disk StorageAPI, xlMeta xlMetaV1) {
-			defer wg.Done()
-
-			// Write unique `xl.json` for a disk at index.
-			mErrs[index] = writeXLMetadata(ctx, disk, bucket, prefix, xlMeta)
-		}(index, disk, xlMetas[index])
+	for index := range disks {
+		index := index
+		g.Go(func() error {
+			if disks[index] == nil {
+				return errDiskNotFound
+			}
+			// Pick one xlMeta for a disk at index.
+			xlMetas[index].Erasure.Index = index + 1
+			return writeXLMetadata(ctx, disks[index], bucket, prefix, xlMetas[index])
+		}, index)
 	}
 
 	// Wait for all the routines.
-	wg.Wait()
+	mErrs := g.Wait()
 
 	err := reduceWriteQuorumErrs(ctx, mErrs, objectOpIgnoredErrs, quorum)
 	return evalDisks(disks, mErrs), err