57 lines
1.4 KiB
Go
57 lines
1.4 KiB
Go
// Copyright (C) 2019 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at https://mozilla.org/MPL/2.0/.
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//go:build linux
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// +build linux
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package fs
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import (
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"io"
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"golang.org/x/sys/unix"
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)
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func init() {
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registerCopyRangeImplementation(CopyRangeMethodIoctl, copyRangeImplementationForBasicFile(copyRangeIoctl))
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}
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func copyRangeIoctl(src, dst basicFile, srcOffset, dstOffset, size int64) error {
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fi, err := src.Stat()
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if err != nil {
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return err
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}
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if srcOffset+size > fi.Size() {
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return io.ErrUnexpectedEOF
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}
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// https://www.man7.org/linux/man-pages/man2/ioctl_ficlonerange.2.html
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// If src_length is zero, the ioctl reflinks to the end of the source file.
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if srcOffset+size == fi.Size() {
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size = 0
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}
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if srcOffset == 0 && dstOffset == 0 && size == 0 {
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// Optimization for whole file copies.
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_, err := withFileDescriptors(src, dst, func(srcFd, dstFd uintptr) (int, error) {
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return 0, unix.IoctlFileClone(int(dstFd), int(srcFd))
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})
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return err
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}
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_, err = withFileDescriptors(src, dst, func(srcFd, dstFd uintptr) (int, error) {
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params := unix.FileCloneRange{
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Src_fd: int64(srcFd),
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Src_offset: uint64(srcOffset),
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Src_length: uint64(size),
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Dest_offset: uint64(dstOffset),
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}
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return 0, unix.IoctlFileCloneRange(int(dstFd), ¶ms)
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})
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return err
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}
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