refactoring

weed/storage/backend/volume_create.go

@@ -0,0 +1,20 @@
+// +build !linux,!windows
+
+package backend
+
+import (
+	"os"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+)
+
+func CreateVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (BackendStorageFile, error) {
+	file, e := os.OpenFile(fileName, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
+	if e != nil {
+		return nil, e
+	}
+	if preallocate > 0 {
+		glog.V(0).Infof("Preallocated disk space for %s is not supported", fileName)
+	}
+	return NewDiskFile(file), nil
+}