add '.healing.bin' for tracking currently healing disk (#10573)

add a hint on the disk to allow for tracking fresh disk
being healed, to allow for restartable heals, and also
use this as a way to track and remove disks.

There are more pending changes where we should move
all the disk formatting logic to backend drives, this
PR doesn't deal with this refactor instead makes it
easier to track healing in the future.

cmd/erasure-bucket.go

@@ -85,31 +85,40 @@ func undoDeleteBucket(storageDisks []StorageAPI, bucket string) {
 
 // getBucketInfo - returns the BucketInfo from one of the load balanced disks.
 func (er erasureObjects) getBucketInfo(ctx context.Context, bucketName string) (bucketInfo BucketInfo, err error) {
-	var bucketErrs []error
-	for _, disk := range er.getLoadBalancedDisks() {
-		if disk == nil {
-			bucketErrs = append(bucketErrs, errDiskNotFound)
-			continue
-		}
-		volInfo, serr := disk.StatVol(ctx, bucketName)
-		if serr == nil {
-			return BucketInfo(volInfo), nil
-		}
-		err = serr
-		// For any reason disk went offline continue and pick the next one.
-		if IsErrIgnored(err, bucketMetadataOpIgnoredErrs...) {
-			bucketErrs = append(bucketErrs, err)
-			continue
-		}
-		// Any error which cannot be ignored, we return quickly.
-		return BucketInfo{}, err
+	storageDisks := er.getDisks()
+
+	g := errgroup.WithNErrs(len(storageDisks))
+	var bucketsInfo = make([]BucketInfo, len(storageDisks))
+	// Undo previous make bucket entry on all underlying storage disks.
+	for index := range storageDisks {
+		index := index
+		g.Go(func() error {
+			if storageDisks[index] == nil {
+				return errDiskNotFound
+			}
+			volInfo, err := storageDisks[index].StatVol(ctx, bucketName)
+			if err != nil {
+				return err
+			}
+			bucketsInfo[index] = BucketInfo(volInfo)
+			return nil
+		}, index)
 	}
+
+	errs := g.Wait()
+
+	for i, err := range errs {
+		if err == nil {
+			return bucketsInfo[i], nil
+		}
+	}
+
 	// If all our errors were ignored, then we try to
 	// reduce to one error based on read quorum.
 	// `nil` is deliberately passed for ignoredErrs
 	// because these errors were already ignored.
-	readQuorum := getReadQuorum(len(er.getDisks()))
-	return BucketInfo{}, reduceReadQuorumErrs(ctx, bucketErrs, nil, readQuorum)
+	readQuorum := getReadQuorum(len(storageDisks))
+	return BucketInfo{}, reduceReadQuorumErrs(ctx, errs, nil, readQuorum)
 }
 
 // GetBucketInfo - returns BucketInfo for a bucket.