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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build !plan9
package renameio
import (
"encoding/binary"
"errors"
"internal/testenv"
"io/ioutil"
"math/rand"
"os"
"path/filepath"
"runtime"
"strings"
"sync"
"sync/atomic"
"syscall"
"testing"
"time"
"cmd/go/internal/robustio"
)
func TestConcurrentReadsAndWrites(t *testing.T) {
if runtime.GOOS == "darwin" && strings.HasSuffix(testenv.Builder(), "-10_14") {
testenv.SkipFlaky(t, 33041)
}
dir, err := ioutil.TempDir("", "renameio")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(dir)
path := filepath.Join(dir, "blob.bin")
const chunkWords = 8 << 10
buf := make([]byte, 2*chunkWords*8)
for i := uint64(0); i < 2*chunkWords; i++ {
binary.LittleEndian.PutUint64(buf[i*8:], i)
}
var attempts int64 = 128
if !testing.Short() {
attempts *= 16
}
const parallel = 32
var sem = make(chan bool, parallel)
var (
writeSuccesses, readSuccesses int64 // atomic
writeErrnoSeen, readErrnoSeen sync.Map
)
for n := attempts; n > 0; n-- {
sem <- true
go func() {
defer func() { <-sem }()
time.Sleep(time.Duration(rand.Intn(100)) * time.Microsecond)
offset := rand.Intn(chunkWords)
chunk := buf[offset*8 : (offset+chunkWords)*8]
if err := WriteFile(path, chunk, 0666); err == nil {
atomic.AddInt64(&writeSuccesses, 1)
} else if robustio.IsEphemeralError(err) {
var (
errno syscall.Errno
dup bool
)
if errors.As(err, &errno) {
_, dup = writeErrnoSeen.LoadOrStore(errno, true)
}
if !dup {
t.Logf("ephemeral error: %v", err)
}
} else {
t.Errorf("unexpected error: %v", err)
}
time.Sleep(time.Duration(rand.Intn(100)) * time.Microsecond)
data, err := ReadFile(path)
if err == nil {
atomic.AddInt64(&readSuccesses, 1)
} else if robustio.IsEphemeralError(err) {
var (
errno syscall.Errno
dup bool
)
if errors.As(err, &errno) {
_, dup = readErrnoSeen.LoadOrStore(errno, true)
}
if !dup {
t.Logf("ephemeral error: %v", err)
}
return
} else {
t.Errorf("unexpected error: %v", err)
return
}
if len(data) != 8*chunkWords {
t.Errorf("read %d bytes, but each write is a %d-byte file", len(data), 8*chunkWords)
return
}
u := binary.LittleEndian.Uint64(data)
for i := 1; i < chunkWords; i++ {
next := binary.LittleEndian.Uint64(data[i*8:])
if next != u+1 {
t.Errorf("wrote sequential integers, but read integer out of sequence at offset %d", i)
return
}
u = next
}
}()
}
for n := parallel; n > 0; n-- {
sem <- true
}
var minWriteSuccesses int64 = attempts
if runtime.GOOS == "windows" {
// Windows produces frequent "Access is denied" errors under heavy rename load.
// As long as those are the only errors and *some* of the writes succeed, we're happy.
minWriteSuccesses = attempts / 4
}
if writeSuccesses < minWriteSuccesses {
t.Errorf("%d (of %d) writes succeeded; want ≥ %d", writeSuccesses, attempts, minWriteSuccesses)
} else {
t.Logf("%d (of %d) writes succeeded (ok: ≥ %d)", writeSuccesses, attempts, minWriteSuccesses)
}
var minReadSuccesses int64 = attempts
switch runtime.GOOS {
case "windows":
// Windows produces frequent "Access is denied" errors under heavy rename load.
// As long as those are the only errors and *some* of the reads succeed, we're happy.
minReadSuccesses = attempts / 4
case "darwin":
// The filesystem on macOS 10.14 occasionally fails with "no such file or
// directory" errors. See https://golang.org/issue/33041. The flake rate is
// fairly low, so ensure that at least 75% of attempts succeed.
minReadSuccesses = attempts - (attempts / 4)
}
if readSuccesses < minReadSuccesses {
t.Errorf("%d (of %d) reads succeeded; want ≥ %d", readSuccesses, attempts, minReadSuccesses)
} else {
t.Logf("%d (of %d) reads succeeded (ok: ≥ %d)", readSuccesses, attempts, minReadSuccesses)
}
}
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