github.com/umbrellaKitties/go-ethereum@v0.0.1/consensus/ethash/mmap_help_linux.go (about)

     1  // Copyright 2021 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  //go:build linux
    18  // +build linux
    19  
    20  package ethash
    21  
    22  import (
    23  	"os"
    24  
    25  	"golang.org/x/sys/unix"
    26  )
    27  
    28  // ensureSize expands the file to the given size. This is to prevent runtime
    29  // errors later on, if the underlying file expands beyond the disk capacity,
    30  // even though it ostensibly is already expanded, but due to being sparse
    31  // does not actually occupy the full declared size on disk.
    32  func ensureSize(f *os.File, size int64) error {
    33  	// Docs: https://www.man7.org/linux/man-pages/man2/fallocate.2.html
    34  	return unix.Fallocate(int(f.Fd()), 0, 0, size)
    35  }