89 lines
1.7 KiB
Go
89 lines
1.7 KiB
Go
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package cowutils
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import (
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"context"
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"os"
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"golang.org/x/sys/unix"
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)
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func DedupeFiles(ctx context.Context, paths []string) (deduped uint64, err error) {
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srcF, err := os.Open(paths[0])
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if err != nil {
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return deduped, err
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}
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defer srcF.Close()
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srcStat, err := srcF.Stat()
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if err != nil {
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return deduped, err
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}
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srcFd := int(srcF.Fd())
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srcSize := srcStat.Size()
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fsStat := unix.Statfs_t{}
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err = unix.Fstatfs(srcFd, &fsStat)
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if err != nil {
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return deduped, err
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}
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if int64(fsStat.Bsize) > srcSize { // for btrfs it means file residing in metadata and can't be deduplicated
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return deduped, nil
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}
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blockSize := uint64((srcSize % int64(fsStat.Bsize)) * int64(fsStat.Bsize))
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fdr := unix.FileDedupeRange{
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Src_offset: 0,
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Src_length: blockSize,
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Info: []unix.FileDedupeRangeInfo{},
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}
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for _, dst := range paths[1:] {
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if ctx.Err() != nil {
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return deduped, ctx.Err()
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}
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destF, err := os.OpenFile(dst, os.O_RDWR, os.ModePerm)
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if err != nil {
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return deduped, err
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}
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// defer in cycle is intended, file must be closed only at the end of the function,
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// and, most importantly, this keeps GC from closing descriptor while dudupe in progress
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defer destF.Close()
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fdr.Info = append(fdr.Info, unix.FileDedupeRangeInfo{
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Dest_fd: int64(destF.Fd()),
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Dest_offset: 0,
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})
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}
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if len(fdr.Info) == 0 {
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return deduped, nil
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}
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if ctx.Err() != nil {
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return deduped, ctx.Err()
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}
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fdr.Src_offset = 0
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for i := range fdr.Info {
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fdr.Info[i].Dest_offset = 0
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}
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err = unix.IoctlFileDedupeRange(srcFd, &fdr)
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if err != nil {
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return deduped, err
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}
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for i := range fdr.Info {
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deduped += fdr.Info[i].Bytes_deduped
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fdr.Info[i].Status = 0
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fdr.Info[i].Bytes_deduped = 0
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}
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return deduped, nil
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}
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