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package main
import (
"bufio"
"fmt"
"io"
"os"
"os/exec"
"path/filepath"
"runtime"
"strconv"
"strings"
"time"
"lib/statusline"
)
//#include <unistd.h>
import "C"
var arg_max = int(C.sysconf(C._SC_ARG_MAX))
func errhandle(err error) {
if err != nil {
panic(err)
}
}
func getFiemaps(paths []string) map[string][]string {
var err error
for i := range paths {
paths[i], err = filepath.Abs(paths[i])
errhandle(err)
}
ret := map[string][]string{}
sl := statusline.NewAsyncStatusLine(os.Stderr, time.Second/2)
cnt := 0
sl.Put("Mapping extents...")
cmd := exec.Command("find", append(paths, "-type", "f", "-exec", "./cow-extent-map", "-m", "--", "{}", "+")...)
stdout, err := cmd.StdoutPipe()
errhandle(err)
cmd.Stderr = os.Stderr
errhandle(cmd.Start())
rd := bufio.NewReader(stdout)
for {
// read filename
filename, err := rd.ReadString('\x00')
if filename == "" && err == io.EOF {
break
}
errhandle(err)
filename = strings.TrimSuffix(filename, "\x00")
if !strings.HasPrefix(filename, "/") {
panic("ugly filename")
}
// read extents
fiemap, err := rd.ReadString('\x00')
errhandle(err)
fiemap = strings.TrimSuffix(fiemap, "\x00")
if !(strings.HasPrefix(fiemap, "logical=") || fiemap == "") {
panic("ugly fiemap")
}
// do stuff
ret[fiemap] = append(ret[fiemap], filename)
cnt++
sl.Put(fmt.Sprintf("Mapping extents... %d", cnt))
}
errhandle(cmd.Wait())
sl.End()
fmt.Fprintf(os.Stderr, "Mapping extents... done; mapped %d files\n", cnt)
return ret
}
func getChecksums(paths []string) map[string][]string {
ret := map[string][]string{}
sl := statusline.NewAsyncStatusLine(os.Stderr, time.Second/2)
cnt := 0
sl.Put(fmt.Sprintf("Generating checksums for files... %d/%d", cnt, len(paths)))
for len(paths) > 0 {
_paths := paths
arg_len := 0
for i := range _paths {
arg_len += len(_paths[i]) + 1
if arg_len > arg_max/2 {
_paths = _paths[:i-1]
break
}
}
paths = paths[len(_paths):]
cmd := exec.Command("sha256sum", append([]string{"--"}, _paths...)...)
stdout, err := cmd.StdoutPipe()
errhandle(err)
cmd.Stderr = os.Stderr
errhandle(cmd.Start())
rd := bufio.NewReader(stdout)
for {
line, err := rd.ReadString('\n')
if line == "" && err == io.EOF {
break
}
errhandle(err)
parts := strings.SplitN(strings.TrimSuffix(line, "\n"), " ", 2)
if len(parts) != 2 {
panic("wut")
}
checksum := parts[0]
filename := strings.TrimPrefix(parts[1], " ")
ret[checksum] = append(ret[checksum], filename)
cnt++
sl.Put(fmt.Sprintf("Generating checksums for files... %d/%d", cnt, len(paths)))
}
errhandle(cmd.Wait())
}
sl.End()
fmt.Fprintf(os.Stderr, "Generating checksums for files... done; summed %d files\n", cnt)
return ret
}
func main() {
// we have low parallelism, don't let syscalls fan-out weird
// on many-core systems
runtime.GOMAXPROCS(2)
fiemap2filenames := getFiemaps(os.Args[1:])
fmt.Fprintf(os.Stderr, "building list of spanning files...")
filename2fiemap := map[string]string{}
for fiemap, filenames := range fiemap2filenames {
for _, filename := range filenames {
if _, ok := filename2fiemap[filename]; ok {
panic("not ok")
}
filename2fiemap[filename] = fiemap
}
}
spanningFiles := make([]string, len(fiemap2filenames))
i := 0
for _, filenames := range fiemap2filenames {
spanningFiles[i] = filenames[0]
i++
}
fmt.Fprintf(os.Stderr, " done\n")
checksum2filenames := getChecksums(spanningFiles)
checksum2fiemaps := map[string][]string{}
for checksum, filenames := range checksum2filenames {
for _, filename := range filenames {
checksum2fiemaps[checksum] = append(checksum2fiemaps[checksum], filename2fiemap[filename])
}
}
for checksum, fiemaps := range checksum2fiemaps {
if len(fiemaps) < 2 {
delete(checksum2fiemaps, checksum)
}
}
fmt.Fprintf(os.Stderr, "Deduplicating %d sets of files...\n", len(checksum2fiemaps))
for checksum, fiemaps := range checksum2fiemaps {
// choose the fiemap with the fewest extents
minFiemap := fiemaps[0]
minFiemapLen := strings.Count(minFiemap, "\n")
for _, fiemap := range fiemaps {
fiemapLen := strings.Count(fiemap, "\n")
if fiemapLen < minFiemapLen {
minFiemap = fiemap
minFiemapLen = fiemapLen
}
}
srcFile := fiemap2filenames[minFiemap][0]
var dupFiles []string
for _, fiemap := range fiemaps {
if fiemap == minFiemap {
continue
}
dupFiles = append(dupFiles, fiemap2filenames[fiemap]...)
}
stat, err := os.Stat(srcFile)
errhandle(err)
args := []string{
"-r", "--", strconv.FormatInt(stat.Size(), 10),
srcFile, "0",
}
for _, dupFile := range dupFiles {
args = append(args, dupFile, "0")
}
cmd := exec.Command("./cow-dedupe-range", args...)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
fmt.Println("#", checksum)
fmt.Println(cmd.Args)
errhandle(cmd.Run())
}
}
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