refactoring

weed/storage/backend/memory_map/memory_map_backend.go

@@ -3,12 +3,10 @@ package memory_map
 import (
 	"os"
 	"time"
-
-	"github.com/chrislusf/seaweedfs/weed/storage/backend"
 )
 
 var (
-	_ backend.BackendStorageFile = &MemoryMappedFile{}
+	// _ backend.BackendStorageFile = &MemoryMappedFile{} // remove this to break import cycle
 )
 
 type MemoryMappedFile struct {

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
+}

weed/storage/backend/volume_create_linux.go

@@ -0,0 +1,22 @@
+// +build linux
+
+package backend
+
+import (
+	"os"
+	"syscall"
+
+	"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 {
+		syscall.Fallocate(int(file.Fd()), 1, 0, preallocate)
+		glog.V(0).Infof("Preallocated %d bytes disk space for %s", preallocate, fileName)
+	}
+	return NewDiskFile(file), nil
+}

weed/storage/backend/volume_create_windows.go

@@ -0,0 +1,32 @@
+// +build windows
+
+package backend
+
+import (
+	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map"
+	"golang.org/x/sys/windows"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/storage/backend/memory_map/os_overloads"
+)
+
+func CreateVolumeFile(fileName string, preallocate int64, memoryMapSizeMB uint32) (BackendStorageFile, error) {
+	if preallocate > 0 {
+		glog.V(0).Infof("Preallocated disk space for %s is not supported", fileName)
+	}
+
+	if memoryMapSizeMB > 0 {
+		file, e := os_overloads.OpenFile(fileName, windows.O_RDWR|windows.O_CREAT, 0644, true)
+		if e != nil {
+			return nil, e
+		}
+		return memory_map.NewMemoryMappedFile(file, memoryMapSizeMB), nil
+	} else {
+		file, e := os_overloads.OpenFile(fileName, windows.O_RDWR|windows.O_CREAT|windows.O_TRUNC, 0644, false)
+		if e != nil {
+			return nil, e
+		}
+		return NewDiskFile(file), nil
+	}
+
+}