Revert "Refactor for Sync method (#3426)"

This reverts commit 670cb759f82815461bc854569542582da51a6199.

with the pr
weed/storage () - (master) > go test -count=1 ./...
ok  	github.com/seaweedfs/seaweedfs/weed/storage	18.486s
?   	github.com/seaweedfs/seaweedfs/weed/storage/backend	[no test files]
ok  	github.com/seaweedfs/seaweedfs/weed/storage/backend/memory_map	0.025s
?   	github.com/seaweedfs/seaweedfs/weed/storage/backend/s3_backend	[no test files]
ok  	github.com/seaweedfs/seaweedfs/weed/storage/erasure_coding	0.864s
?   	github.com/seaweedfs/seaweedfs/weed/storage/idx	[no test files]
ok  	github.com/seaweedfs/seaweedfs/weed/storage/needle	0.110s
ok  	github.com/seaweedfs/seaweedfs/weed/storage/needle_map	24.414s
ok  	github.com/seaweedfs/seaweedfs/weed/storage/super_block	0.203s
?   	github.com/seaweedfs/seaweedfs/weed/storage/types	[no test files]
?   	github.com/seaweedfs/seaweedfs/weed/storage/volume_info	[no test files]
weed/storage () - (master) >
weed/storage () - (master) >

without the pr
weed/storage () - (master) >
weed/storage () - (master) > go test -count=1 ./...
ok  	github.com/seaweedfs/seaweedfs/weed/storage	1.617s
?   	github.com/seaweedfs/seaweedfs/weed/storage/backend	[no test files]
ok  	github.com/seaweedfs/seaweedfs/weed/storage/backend/memory_map	0.026s
?   	github.com/seaweedfs/seaweedfs/weed/storage/backend/s3_backend	[no test files]
ok  	github.com/seaweedfs/seaweedfs/weed/storage/erasure_coding	0.906s
?   	github.com/seaweedfs/seaweedfs/weed/storage/idx	[no test files]
ok  	github.com/seaweedfs/seaweedfs/weed/storage/needle	0.202s
ok  	github.com/seaweedfs/seaweedfs/weed/storage/needle_map	24.533s
ok  	github.com/seaweedfs/seaweedfs/weed/storage/super_block	0.280s
?   	github.com/seaweedfs/seaweedfs/weed/storage/types	[no test files]
?   	github.com/seaweedfs/seaweedfs/weed/storage/volume_info	[no test files]

4 files changed, 7 insertions, 69 deletions

diff --git a/weed/storage/backend/disk_file.go b/weed/storage/backend/disk_file.go
index 93a2f8ccc..0dd153d5d 100644
--- a/weed/storage/backend/disk_file.go
+++ b/weed/storage/backend/disk_file.go
@@ -1,11 +1,10 @@
 package backend
 
 import (
-	"os"
-	"time"
-
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	. "github.com/seaweedfs/seaweedfs/weed/storage/types"
+	"os"
+	"time"
 )
 
 var (
@@ -80,3 +79,8 @@ func (df *DiskFile) GetStat() (datSize int64, modTime time.Time, err error) {
 func (df *DiskFile) Name() string {
 	return df.fullFilePath
 }
+
+func (df *DiskFile) Sync() error {
+	return nil
+	// return df.File.Sync()
+}
diff --git a/weed/storage/backend/disk_file_darwin.go b/weed/storage/backend/disk_file_darwin.go
deleted file mode 100644
index 76be810db..000000000
--- a/weed/storage/backend/disk_file_darwin.go
+++ /dev/null
@@ -1,43 +0,0 @@
-//go:build darwin
-// +build darwin
-
-package backend
-
-import (
-	"syscall"
-
-	"golang.org/x/sys/unix"
-)
-
-const (
-	// Using default File.Sync function, same as fcntl(fd, F_FULLFSYNC)
-	DM_SYNC = 1
-
-	// Using syscall.Fsync function, for MacOS this is not safe but is very fast.
-	DM_FSYNC = 2
-
-	// Using fcntl with F_BARRIERFSYNC parameter, for more details please refer:
-	// https://developer.apple.com/documentation/xcode/reducing-disk-writes
-	DM_BFSYNC = 3
-
-	F_BARRIERFSYNC = 85
-)
-
-var (
-	// By default using F_BARRIERFSYNC
-	DarwinSyncMode = DM_BFSYNC
-)
-
-func (df *DiskFile) Sync() error {
-	switch DarwinSyncMode {
-	case DM_SYNC:
-		return df.File.Sync()
-	case DM_BFSYNC:
-		fd := df.File.Fd()
-		_, err := unix.FcntlInt(fd, F_BARRIERFSYNC, 0)
-		return err
-	default:
-		fd := df.File.Fd()
-		return syscall.Fsync(int(fd))
-	}
-}
diff --git a/weed/storage/backend/disk_file_linux.go b/weed/storage/backend/disk_file_linux.go
deleted file mode 100644
index a38489dcf..000000000
--- a/weed/storage/backend/disk_file_linux.go
+++ /dev/null
@@ -1,14 +0,0 @@
-//go:build linux
-// +build linux
-
-package backend
-
-import (
-	"syscall"
-)
-
-// Using Fdatasync to optimize file sync operation
-func (df *DiskFile) Sync() error {
-	fd := df.File.Fd()
-	return syscall.Fdatasync(int(fd))
-}
diff --git a/weed/storage/backend/disk_file_others.go b/weed/storage/backend/disk_file_others.go
deleted file mode 100644
index 08d29d217..000000000
--- a/weed/storage/backend/disk_file_others.go
+++ /dev/null
@@ -1,9 +0,0 @@
-//go:build !linux && !darwin
-// +build !linux,!darwin
-
-package backend
-
-// Using default sync operation
-func (df *DiskFile) Sync() error {
-	return df.File.Sync()
-}