introduce 'mc admin config set alias/ api odirect=on' (#17753)

change disable_odirect=off -> odirect=on to make it
easier to understand, instead of making it double
negative.

cmd/xl-storage.go

@@ -284,7 +284,7 @@ func newXLStorage(ep Endpoint, cleanUp bool) (s *xlStorage, err error) {
 		s.formatLegacy = format.Erasure.DistributionAlgo == formatErasureVersionV2DistributionAlgoV1
 	}
 
-	if !globalAPIConfig.isDisableODirect() {
+	if globalAPIConfig.odirectEnabled() {
 		// Return an error if ODirect is not supported
 		// unless it is a single erasure disk mode
 		if err := s.checkODirectDiskSupport(); err == nil {
@@ -1480,7 +1480,7 @@ func (s *xlStorage) readAllData(ctx context.Context, volumeDir string, filePath
 		return nil, time.Time{}, ctx.Err()
 	}
 
-	odirectEnabled := !globalAPIConfig.isDisableODirect() && s.oDirect
+	odirectEnabled := globalAPIConfig.odirectEnabled() && s.oDirect
 	var f *os.File
 	if odirectEnabled {
 		f, err = OpenFileDirectIO(filePath, readMode, 0o666)
@@ -1761,7 +1761,7 @@ func (s *xlStorage) ReadFileStream(ctx context.Context, volume, path string, off
 		return nil, err
 	}
 
-	odirectEnabled := !globalAPIConfig.isDisableODirect() && s.oDirect
+	odirectEnabled := globalAPIConfig.odirectEnabled() && s.oDirect
 
 	var file *os.File
 	if odirectEnabled {
@@ -1898,7 +1898,7 @@ func (s *xlStorage) writeAllDirect(ctx context.Context, filePath string, fileSiz
 		return osErrToFileErr(err)
 	}
 
-	odirectEnabled := !globalAPIConfig.isDisableODirect() && s.oDirect
+	odirectEnabled := globalAPIConfig.odirectEnabled() && s.oDirect
 
 	var w *os.File
 	if odirectEnabled {