etcd-io__etcd/pkg/fileutil/preallocate.go

// Copyright 2015 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// +build linux

package fileutil

import (
	"os"
	"syscall"
)

func Preallocate(f *os.File, sizeInBytes int) error {
	// use mode = 1 to keep size
	// see FALLOC_FL_KEEP_SIZE
	return syscall.Fallocate(int(f.Fd()), 1, 0, int64(sizeInBytes))
}