From 670cb759f82815461bc854569542582da51a6199 Mon Sep 17 00:00:00 2001
From: Rain Li <blacktear23@gmail.com>
Date: Wed, 10 Aug 2022 23:21:57 +0800
Subject: [PATCH] Refactor for Sync method (#3426)

---
 weed/storage/backend/disk_file.go        | 10 ++----
 weed/storage/backend/disk_file_darwin.go | 43 ++++++++++++++++++++++++
 weed/storage/backend/disk_file_linux.go  | 14 ++++++++
 weed/storage/backend/disk_file_others.go |  9 +++++
 4 files changed, 69 insertions(+), 7 deletions(-)
 create mode 100644 weed/storage/backend/disk_file_darwin.go
 create mode 100644 weed/storage/backend/disk_file_linux.go
 create mode 100644 weed/storage/backend/disk_file_others.go

diff --git a/weed/storage/backend/disk_file.go b/weed/storage/backend/disk_file.go
index 0dd153d5d..93a2f8ccc 100644
--- a/weed/storage/backend/disk_file.go
+++ b/weed/storage/backend/disk_file.go
@@ -1,10 +1,11 @@
 package backend
 
 import (
-	"github.com/seaweedfs/seaweedfs/weed/glog"
-	. "github.com/seaweedfs/seaweedfs/weed/storage/types"
 	"os"
 	"time"
+
+	"github.com/seaweedfs/seaweedfs/weed/glog"
+	. "github.com/seaweedfs/seaweedfs/weed/storage/types"
 )
 
 var (
@@ -79,8 +80,3 @@ 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
new file mode 100644
index 000000000..76be810db
--- /dev/null
+++ b/weed/storage/backend/disk_file_darwin.go
@@ -0,0 +1,43 @@
+//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
new file mode 100644
index 000000000..a38489dcf
--- /dev/null
+++ b/weed/storage/backend/disk_file_linux.go
@@ -0,0 +1,14 @@
+//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
new file mode 100644
index 000000000..08d29d217
--- /dev/null
+++ b/weed/storage/backend/disk_file_others.go
@@ -0,0 +1,9 @@
+//go:build !linux && !darwin
+// +build !linux,!darwin
+
+package backend
+
+// Using default sync operation
+func (df *DiskFile) Sync() error {
+	return df.File.Sync()
+}