mirror of
https://github.com/yunionio/cloudpods.git
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61 lines
1.4 KiB
Go
61 lines
1.4 KiB
Go
// Copyright 2019 Yunion
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build linux
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// +build linux
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package sparsefile
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import (
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"io"
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"os"
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"syscall"
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"golang.org/x/sys/unix"
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)
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const (
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SEEK_DATA = 3
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SEEK_HOLE = 4
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)
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func detectHoles(file *os.File) ([]sSparseHole, error) {
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holes := []sSparseHole{}
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offset := int64(0)
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for {
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start, err := unix.Seek(int(file.Fd()), offset, SEEK_HOLE)
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if err != nil {
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if e, ok := err.(syscall.Errno); ok && e == syscall.ENXIO {
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break
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}
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return nil, err
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}
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end, err := unix.Seek(int(file.Fd()), start, SEEK_DATA)
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if err != nil {
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if e, ok := err.(syscall.Errno); ok && e == syscall.ENXIO {
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end, _ = file.Seek(0, io.SeekEnd)
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if end > start {
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holes = append(holes, sSparseHole{Offset: start, Length: end - start})
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}
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break
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}
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return nil, err
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}
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offset = end
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holes = append(holes, sSparseHole{Offset: start, Length: end - start})
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}
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return holes, nil
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}
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