err = dc.ReadNil()
				if err != nil {
					err = msgp.WrapError(err, "Compress")
					return
				}
				z.Compress = nil
			} else {
				if z.Compress == nil {
					z.Compress = new(bool)
				}
				*z.Compress, err = dc.ReadBool()
				if err != nil {
					err = msgp.WrapError(err, "Compress")
					return
				}
			}
		case "SmallerThan":
			if dc.IsNil() {
				err = dc.ReadNil()

	var found int
	var notFound int
	var foundNotEmpty int
	var otherFound int
	for _, readErr := range errs {
		switch {
		case readErr == nil:
			found++
		case readErr == errFileNotFound || readErr == errVolumeNotFound:
			notFound++
		case readErr == errVolumeNotEmpty:
			foundNotEmpty++
		default:
			otherFound++
		}
	}
	found = found + foundNotEmpty + otherFound

	if err != io.EOF {
		t.Fatal(err)
	}
}

func Test_metacacheReader_readAll(t *testing.T) {
	r := loadMetacacheSample(t)
	defer r.Close()
	var readErr error
	objs := make(chan metaCacheEntry, 1)
	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		readErr = r.readAll(context.Background(), objs)
		wg.Done()
	}()
	want := loadMetacacheSampleNames
	i := 0
	for entry := range objs {

//sys	pread(fd int, p []byte, offset int64) (n int, err error)
//sys	pwrite(fd int, p []byte, offset int64) (n int, err error)
//sys	read(fd int, p []byte) (n int, err error)
//sys	readdir_r(dir uintptr, entry *Dirent, result **Dirent) (res Errno)
//sys	Readlink(path string, buf []byte) (n int, err error)
//sys	Rename(from string, to string) (err error)
//sys	Revoke(path string) (err error)

	}

	// This code assumes that d.r strips supported whitespace ('\r' and '\n').

	// Refill buffer.
	for d.nbuf < 4 && d.readErr == nil {
		nn := len(p) / 3 * 4
		if nn < 4 {
			nn = 4
		}
		if nn > len(d.buf) {
			nn = len(d.buf)
		}
		nn, d.readErr = d.r.Read(d.buf[d.nbuf:nn])
		d.nbuf += nn
	}

	if d.nbuf < 4 {
		if d.enc.padChar == NoPadding && d.nbuf > 0 {

func xremoveall(p string) {
	if vflag > 2 {
		errprintf("rm -r %s\n", p)
	}
	os.RemoveAll(p)
}

// xreaddir replaces dst with a list of the names of the files and subdirectories in dir.
// The names are relative to dir; they are not full paths.
func xreaddir(dir string) []string {
	f, err := os.Open(dir)
	if err != nil {
		fatalf("%v", err)
	}
	defer f.Close()

		// error is returned.
		{r: badReader{data: []byte("MY====="), errs: []error{badErr}},
			res: "", err: badErr},
		// Reader returns invalid input data (too short) but no error.  Verify io.ErrUnexpectedEOF
		// is returned.
		{r: badReader{data: []byte("MY====="), errs: []error{nil}},
			res: "", err: io.ErrUnexpectedEOF},
		// Reader returns invalid input data and an error.  Verify the reader and not the

	repeats     uint     // the number of copies of lastByte to output.
}

// NewReader returns an io.Reader which decompresses bzip2 data from r.
// If r does not also implement [io.ByteReader],
// the decompressor may read more data than necessary from r.
func NewReader(r io.Reader) io.Reader {
	bz2 := new(reader)
	bz2.br = newBitReader(r)
	return bz2
}

const bzip2FileMagic = 0x425a // "BZ"

	diffStats := getDiffStats(latestStats, currentStats)

	updateResourceMetrics(driveSubsystem, readsPerSec, float64(diffStats.ReadIOs)/diffInSeconds, labels, false)
	readKib := float64(diffStats.ReadSectors*sectorSize) / kib
	updateResourceMetrics(driveSubsystem, readsKBPerSec, readKib/diffInSeconds, labels, false)

	updateResourceMetrics(driveSubsystem, writesPerSec, float64(diffStats.WriteIOs)/diffInSeconds, labels, false)

	//
	// If the requested file does not exist it should return an error for which
	// os.IsNotExist(err) returns true.
	ReadFile(ctx context.Context, rev, file string, maxSize int64) (data []byte, err error)

	// ReadZip downloads a zip file for the subdir subdirectory
	// of the given revision to a new file in a given temporary directory.
	// It should refuse to read more than maxSize bytes.