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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 myStatusLine() statusline.StatusLine {
return statusline.StopWatch(statusline.RateLimit(statusline.New(os.Stderr), time.Second/2), time.Second)
}
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 := myStatusLine()
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.Put(fmt.Sprintf("Mapping extents... done; mapped %d files", cnt))
sl.End(true)
return ret
}
func getChecksums(cmd []string, paths []string) map[string][]string {
ret := map[string][]string{}
sl := myStatusLine()
cnt := 0
sl.Put(fmt.Sprintf("Generating checksums (%v) for files... %d/%d", cmd, cnt, len(paths)))
pathsTodo := paths
for len(pathsTodo) > 0 {
pathsDoing := pathsTodo
arg_len := 0
for i := range pathsDoing {
arg_len += len(pathsDoing[i]) + 1
if arg_len > arg_max/2 {
pathsDoing = pathsDoing[:i-1]
break
}
}
pathsTodo = pathsTodo[len(pathsDoing):]
cmd := exec.Command(cmd[0], append(cmd[1:], pathsDoing...)...)
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 (%v) for files... %d/%d", cmd, cnt, len(paths)))
}
errhandle(cmd.Wait())
}
sl.Put(fmt.Sprintf("Generating checksums (%v) for files... done; summed %d files", cmd, cnt))
sl.End(true)
return ret
}
func pruneSingles(key2vals map[string][]string) {
for key, vals := range key2vals {
if len(vals) < 2 {
delete(key2vals, key)
}
}
}
func dedupe(srcFile string, dupFiles []string) error {
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)
return cmd.Run()
}
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:])
sl := statusline.StopWatch(statusline.New(os.Stderr), time.Second)
sl.Put( "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++
}
sl.Put(fmt.Sprintf("Building list of spanning files... done; %d files", len(spanningFiles)))
sl.End(true)
size2filenames := getChecksums([]string{"stat", "--printf=%s %n\\n", "--"}, spanningFiles)
fmt.Fprintf(" -> %d sets", len(size2filenames))
pruneSingles(size2filenames)
fmt.Fprintf(" -> %d non-trivial sets\n", len(size2filenames))
sl = myStatusLine()
sizeCnt := 0
for size, filenames := range size2filenames {
// The list of specific files in size2filenames isn't
// significant; they'e just proxies for fiemaps.
sizeStatus := fmt.Sprintf("Working on size-set %d/%d of %d fiemaps",
sizeCnt, len(size2filenames), len(filenames))
sl.Put(sizeStatus)
// Now do strict hashing, instead of the incredibly
// sloppy (but fast) size-bucketing.
checksum2filenames := getChecksums([]string{"sha256sum", "--"}, filenames)
pruneSingles(checksum2filenames)
// And loop over the smaller, precise buckets
sumCnt := 0
for checksum, filenames := range checksum2fiemaps {
sl.Put(fmt.Sprintf("%s :: sha256-set %d/%d of %d fiemaps", sizeStatus, sumCnt, len(checksum2filenames), len(filenames)))
var fiemaps []string
for _, filename := range filenames {
fiemaps = append(fiemaps, filename2fiemap[filename])
}
// Now we 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
}
}
// Set srcFile and dupFiles based on that
srcFile := fiemap2filenames[minFiemap][0]
var dupFiles []string
for _, fiemap := range fiemaps {
if fiemap == minFiemap {
continue
}
dupFiles = append(dupFiles, fiemap2filenames[fiemap]...)
}
// And actually dedupe those
dedupe(srcFile, dupFiles) // XXX ignore error?
sumCnt++
}
sizeCnt++
}
sl.Put(fmt.Sprintf("Working on size-set %d/%d... done", sizeCnt, len(size2filenames)))
sl.End(true)
}
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