fix: calling statfs() call moves the disk head (#18203)

if erasure upgrade is needed rely on the in-memory
values, instead of performing a "DiskInfo()" call.

https://brendangregg.com/blog/2016-09-03/sudden-disk-busy.html

for HDDs these are problematic, lets avoid this because
there is no value in "being" absolutely strict here
in terms of parity. We are okay to increase parity
as we see based on the in-memory online/offline ratio.

cmd/erasure-object.go

@@ -47,7 +47,6 @@ import (
 	"github.com/minio/pkg/v2/sync/errgroup"
 	"github.com/minio/pkg/v2/wildcard"
 	"github.com/tinylib/msgp/msgp"
-	uatomic "go.uber.org/atomic"
 )
 
 // list all errors which can be ignored in object operations.
@@ -1097,47 +1096,31 @@ func (er erasureObjects) putObject(ctx context.Context, bucket string, object st
 		// If we have offline disks upgrade the number of erasure codes for this object.
 		parityOrig := parityDrives
 
-		atomicParityDrives := uatomic.NewInt64(0)
-		atomicOfflineDrives := uatomic.NewInt64(0)
-
-		// Start with current parityDrives
-		atomicParityDrives.Store(int64(parityDrives))
-
-		var wg sync.WaitGroup
+		var offlineDrives int
 		for _, disk := range storageDisks {
 			if disk == nil {
-				atomicParityDrives.Inc()
-				atomicOfflineDrives.Inc()
+				parityDrives++
+				offlineDrives++
 				continue
 			}
 			if !disk.IsOnline() {
-				atomicParityDrives.Inc()
-				atomicOfflineDrives.Inc()
+				parityDrives++
+				offlineDrives++
 				continue
 			}
-			wg.Add(1)
-			go func(disk StorageAPI) {
-				defer wg.Done()
-				di, err := disk.DiskInfo(ctx, false)
-				if err != nil || di.ID == "" {
-					atomicOfflineDrives.Inc()
-					atomicParityDrives.Inc()
-				}
-			}(disk)
 		}
-		wg.Wait()
 
-		if int(atomicOfflineDrives.Load()) >= (len(storageDisks)+1)/2 {
+		if offlineDrives >= (len(storageDisks)+1)/2 {
 			// if offline drives are more than 50% of the drives
 			// we have no quorum, we shouldn't proceed just
 			// fail at that point.
 			return ObjectInfo{}, toObjectErr(errErasureWriteQuorum, bucket, object)
 		}
 
-		parityDrives = int(atomicParityDrives.Load())
 		if parityDrives >= len(storageDisks)/2 {
 			parityDrives = len(storageDisks) / 2
 		}
+
 		if parityOrig != parityDrives {
 			userDefined[minIOErasureUpgraded] = strconv.Itoa(parityOrig) + "->" + strconv.Itoa(parityDrives)
 		}