add option for O_SYNC writes for standalone FS backend (#9581)

cmd/common-main.go

@@ -186,6 +186,11 @@ func handleCommonEnvVars() {
 		logger.Fatal(config.ErrInvalidBrowserValue(err), "Invalid MINIO_BROWSER value in environment variable")
 	}
 
+	globalFSOSync, err = config.ParseBool(env.Get(config.EnvFSOSync, config.EnableOff))
+	if err != nil {
+		logger.Fatal(config.ErrInvalidFSOSyncValue(err), "Invalid MINIO_FS_OSYNC value in environment variable")
+	}
+
 	domains := env.Get(config.EnvDomain, "")
 	if len(domains) != 0 {
 		for _, domainName := range strings.Split(domains, config.ValueSeparator) {

cmd/config/constants.go

@@ -32,6 +32,7 @@ const (
 	EnvRegionName   = "MINIO_REGION_NAME"
 	EnvPublicIPs    = "MINIO_PUBLIC_IPS"
 	EnvEndpoints    = "MINIO_ENDPOINTS"
+	EnvFSOSync      = "MINIO_FS_OSYNC"
 
 	// API sub-system
 	EnvAPIRequestsMax      = "MINIO_API_REQUESTS_MAX"

cmd/config/errors.go

@@ -24,6 +24,12 @@ var (
 		"Browser can only accept `on` and `off` values. To disable web browser access, set this value to `off`",
 	)
 
+	ErrInvalidFSOSyncValue = newErrFn(
+		"Invalid O_SYNC value",
+		"Please check the passed value",
+		"Can only accept `on` and `off` values. To enable O_SYNC for fs backend, set this value to `on`",
+	)
+
 	ErrInvalidDomainValue = newErrFn(
 		"Invalid domain value",
 		"Please check the passed value",

cmd/fs-v1-helpers.go

@@ -321,7 +321,11 @@ func fsCreateFile(ctx context.Context, filePath string, reader io.Reader, buf []
 		return 0, err
 	}
 
-	writer, err := lock.Open(filePath, os.O_CREATE|os.O_WRONLY, 0666)
+	flags := os.O_CREATE | os.O_WRONLY
+	if globalFSOSync {
+		flags = flags | os.O_SYNC
+	}
+	writer, err := lock.Open(filePath, flags, 0666)
 	if err != nil {
 		return 0, osErrToFSFileErr(err)
 	}

cmd/fs-v1-multipart.go

@@ -112,7 +112,7 @@ func (fs *FSObjects) backgroundAppend(ctx context.Context, bucket, object, uploa
 		}
 
 		partPath := pathJoin(uploadIDDir, entry)
-		err = mioutil.AppendFile(file.filePath, partPath)
+		err = mioutil.AppendFile(file.filePath, partPath, globalFSOSync)
 		if err != nil {
 			reqInfo := logger.GetReqInfo(ctx).AppendTags("partPath", partPath)
 			reqInfo.AppendTags("filepath", file.filePath)
@@ -638,7 +638,7 @@ func (fs *FSObjects) CompleteMultipartUpload(ctx context.Context, bucket string,
 		}
 		for _, part := range parts {
 			partPath := getPartFile(entries, part.PartNumber, part.ETag)
-			if err = mioutil.AppendFile(appendFilePath, pathJoin(uploadIDDir, partPath)); err != nil {
+			if err = mioutil.AppendFile(appendFilePath, pathJoin(uploadIDDir, partPath), globalFSOSync); err != nil {
 				logger.LogIf(ctx, err)
 				return oi, toObjectErr(err)
 			}

cmd/globals.go

@@ -280,6 +280,8 @@ var (
 	// fix the system.
 	globalSafeMode bool
 
+	// If writes to FS backend should be O_SYNC.
+	globalFSOSync bool
 	// Add new variable global values here.
 )
 

pkg/ioutil/append-file_nix.go

@@ -24,8 +24,12 @@ import (
 )
 
 // AppendFile - appends the file "src" to the file "dst"
-func AppendFile(dst string, src string) error {
+func AppendFile(dst string, src string, osync bool) error {
-	appendFile, err := os.OpenFile(dst, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666)
+	flags := os.O_WRONLY | os.O_APPEND | os.O_CREATE
+	if osync {
+		flags = flags | os.O_SYNC
+	}
+	appendFile, err := os.OpenFile(dst, flags, 0666)
 	if err != nil {
 		return err
 	}

pkg/ioutil/append-file_windows.go

@@ -24,7 +24,7 @@ import (
 )
 
 // AppendFile - appends the file "src" to the file "dst"
-func AppendFile(dst string, src string) error {
+func AppendFile(dst string, src string, osync bool) error {
 	appendFile, err := lock.Open(dst, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0644)
 	if err != nil {
 		return err

pkg/ioutil/ioutil_test.go

@@ -61,7 +61,7 @@ func TestAppendFile(t *testing.T) {
 	f.WriteString("bbbbbbbbbb")
 	f.Close()
 
-	if err = AppendFile(name1, name2); err != nil {
+	if err = AppendFile(name1, name2, false); err != nil {
 		t.Error(err)
 	}