mirror of
https://gitlab.com/pulsechaincom/go-pulse.git
synced 2024-12-25 04:47:17 +00:00
615 lines
16 KiB
Go
615 lines
16 KiB
Go
// Copyright 2019 The go-ethereum Authors
|
|
// This file is part of the go-ethereum library.
|
|
//
|
|
// The go-ethereum library is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Lesser General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// The go-ethereum library is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Lesser General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Lesser General Public License
|
|
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
package rawdb
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"math/rand"
|
|
"os"
|
|
"path/filepath"
|
|
"testing"
|
|
"time"
|
|
|
|
"github.com/ethereum/go-ethereum/metrics"
|
|
)
|
|
|
|
func init() {
|
|
rand.Seed(time.Now().Unix())
|
|
}
|
|
|
|
// Gets a chunk of data, filled with 'b'
|
|
func getChunk(size int, b int) []byte {
|
|
data := make([]byte, size)
|
|
for i := range data {
|
|
data[i] = byte(b)
|
|
}
|
|
return data
|
|
}
|
|
|
|
// TestFreezerBasics test initializing a freezertable from scratch, writing to the table,
|
|
// and reading it back.
|
|
func TestFreezerBasics(t *testing.T) {
|
|
t.Parallel()
|
|
// set cutoff at 50 bytes
|
|
f, err := newCustomTable(os.TempDir(),
|
|
fmt.Sprintf("unittest-%d", rand.Uint64()),
|
|
metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge(), 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
defer f.Close()
|
|
// Write 15 bytes 255 times, results in 85 files
|
|
for x := 0; x < 255; x++ {
|
|
data := getChunk(15, x)
|
|
f.Append(uint64(x), data)
|
|
}
|
|
|
|
//print(t, f, 0)
|
|
//print(t, f, 1)
|
|
//print(t, f, 2)
|
|
//
|
|
//db[0] = 000000000000000000000000000000
|
|
//db[1] = 010101010101010101010101010101
|
|
//db[2] = 020202020202020202020202020202
|
|
|
|
for y := 0; y < 255; y++ {
|
|
exp := getChunk(15, y)
|
|
got, err := f.Retrieve(uint64(y))
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if !bytes.Equal(got, exp) {
|
|
t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
|
|
}
|
|
}
|
|
// Check that we cannot read too far
|
|
_, err = f.Retrieve(uint64(255))
|
|
if err != errOutOfBounds {
|
|
t.Fatal(err)
|
|
}
|
|
}
|
|
|
|
// TestFreezerBasicsClosing tests same as TestFreezerBasics, but also closes and reopens the freezer between
|
|
// every operation
|
|
func TestFreezerBasicsClosing(t *testing.T) {
|
|
t.Parallel()
|
|
// set cutoff at 50 bytes
|
|
var (
|
|
fname = fmt.Sprintf("basics-close-%d", rand.Uint64())
|
|
rm, wm, sg = metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
f *freezerTable
|
|
err error
|
|
)
|
|
f, err = newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 15 bytes 255 times, results in 85 files
|
|
for x := 0; x < 255; x++ {
|
|
data := getChunk(15, x)
|
|
f.Append(uint64(x), data)
|
|
f.Close()
|
|
f, err = newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
}
|
|
defer f.Close()
|
|
|
|
for y := 0; y < 255; y++ {
|
|
exp := getChunk(15, y)
|
|
got, err := f.Retrieve(uint64(y))
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if !bytes.Equal(got, exp) {
|
|
t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
|
|
}
|
|
f.Close()
|
|
f, err = newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
}
|
|
}
|
|
|
|
// TestFreezerRepairDanglingHead tests that we can recover if index entries are removed
|
|
func TestFreezerRepairDanglingHead(t *testing.T) {
|
|
t.Parallel()
|
|
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
fname := fmt.Sprintf("dangling_headtest-%d", rand.Uint64())
|
|
|
|
{ // Fill table
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 15 bytes 255 times
|
|
for x := 0; x < 255; x++ {
|
|
data := getChunk(15, x)
|
|
f.Append(uint64(x), data)
|
|
}
|
|
// The last item should be there
|
|
if _, err = f.Retrieve(0xfe); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
f.Close()
|
|
}
|
|
// open the index
|
|
idxFile, err := os.OpenFile(filepath.Join(os.TempDir(), fmt.Sprintf("%s.ridx", fname)), os.O_RDWR, 0644)
|
|
if err != nil {
|
|
t.Fatalf("Failed to open index file: %v", err)
|
|
}
|
|
// Remove 4 bytes
|
|
stat, err := idxFile.Stat()
|
|
if err != nil {
|
|
t.Fatalf("Failed to stat index file: %v", err)
|
|
}
|
|
idxFile.Truncate(stat.Size() - 4)
|
|
idxFile.Close()
|
|
// Now open it again
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// The last item should be missing
|
|
if _, err = f.Retrieve(0xff); err == nil {
|
|
t.Errorf("Expected error for missing index entry")
|
|
}
|
|
// The one before should still be there
|
|
if _, err = f.Retrieve(0xfd); err != nil {
|
|
t.Fatalf("Expected no error, got %v", err)
|
|
}
|
|
}
|
|
}
|
|
|
|
// TestFreezerRepairDanglingHeadLarge tests that we can recover if very many index entries are removed
|
|
func TestFreezerRepairDanglingHeadLarge(t *testing.T) {
|
|
t.Parallel()
|
|
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
fname := fmt.Sprintf("dangling_headtest-%d", rand.Uint64())
|
|
|
|
{ // Fill a table and close it
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 15 bytes 255 times
|
|
for x := 0; x < 0xff; x++ {
|
|
data := getChunk(15, x)
|
|
f.Append(uint64(x), data)
|
|
}
|
|
// The last item should be there
|
|
if _, err = f.Retrieve(f.items - 1); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
f.Close()
|
|
}
|
|
// open the index
|
|
idxFile, err := os.OpenFile(filepath.Join(os.TempDir(), fmt.Sprintf("%s.ridx", fname)), os.O_RDWR, 0644)
|
|
if err != nil {
|
|
t.Fatalf("Failed to open index file: %v", err)
|
|
}
|
|
// Remove everything but the first item, and leave data unaligned
|
|
// 0-indexEntry, 1-indexEntry, corrupt-indexEntry
|
|
idxFile.Truncate(indexEntrySize + indexEntrySize + indexEntrySize/2)
|
|
idxFile.Close()
|
|
// Now open it again
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// The first item should be there
|
|
if _, err = f.Retrieve(0); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// The second item should be missing
|
|
if _, err = f.Retrieve(1); err == nil {
|
|
t.Errorf("Expected error for missing index entry")
|
|
}
|
|
// We should now be able to store items again, from item = 1
|
|
for x := 1; x < 0xff; x++ {
|
|
data := getChunk(15, ^x)
|
|
f.Append(uint64(x), data)
|
|
}
|
|
f.Close()
|
|
}
|
|
// And if we open it, we should now be able to read all of them (new values)
|
|
{
|
|
f, _ := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
for y := 1; y < 255; y++ {
|
|
exp := getChunk(15, ^y)
|
|
got, err := f.Retrieve(uint64(y))
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if !bytes.Equal(got, exp) {
|
|
t.Fatalf("test %d, got \n%x != \n%x", y, got, exp)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// TestSnappyDetection tests that we fail to open a snappy database and vice versa
|
|
func TestSnappyDetection(t *testing.T) {
|
|
t.Parallel()
|
|
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
fname := fmt.Sprintf("snappytest-%d", rand.Uint64())
|
|
// Open with snappy
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 15 bytes 255 times
|
|
for x := 0; x < 0xff; x++ {
|
|
data := getChunk(15, x)
|
|
f.Append(uint64(x), data)
|
|
}
|
|
f.Close()
|
|
}
|
|
// Open without snappy
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, false)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if _, err = f.Retrieve(0); err == nil {
|
|
f.Close()
|
|
t.Fatalf("expected empty table")
|
|
}
|
|
}
|
|
|
|
// Open with snappy
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// There should be 255 items
|
|
if _, err = f.Retrieve(0xfe); err != nil {
|
|
f.Close()
|
|
t.Fatalf("expected no error, got %v", err)
|
|
}
|
|
}
|
|
|
|
}
|
|
func assertFileSize(f string, size int64) error {
|
|
stat, err := os.Stat(f)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if stat.Size() != size {
|
|
return fmt.Errorf("error, expected size %d, got %d", size, stat.Size())
|
|
}
|
|
return nil
|
|
|
|
}
|
|
|
|
// TestFreezerRepairDanglingIndex checks that if the index has more entries than there are data,
|
|
// the index is repaired
|
|
func TestFreezerRepairDanglingIndex(t *testing.T) {
|
|
t.Parallel()
|
|
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
fname := fmt.Sprintf("dangling_indextest-%d", rand.Uint64())
|
|
|
|
{ // Fill a table and close it
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 15 bytes 9 times : 150 bytes
|
|
for x := 0; x < 9; x++ {
|
|
data := getChunk(15, x)
|
|
f.Append(uint64(x), data)
|
|
}
|
|
// The last item should be there
|
|
if _, err = f.Retrieve(f.items - 1); err != nil {
|
|
f.Close()
|
|
t.Fatal(err)
|
|
}
|
|
f.Close()
|
|
// File sizes should be 45, 45, 45 : items[3, 3, 3)
|
|
}
|
|
// Crop third file
|
|
fileToCrop := filepath.Join(os.TempDir(), fmt.Sprintf("%s.0002.rdat", fname))
|
|
// Truncate third file: 45 ,45, 20
|
|
{
|
|
if err := assertFileSize(fileToCrop, 45); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
file, err := os.OpenFile(fileToCrop, os.O_RDWR, 0644)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
file.Truncate(20)
|
|
file.Close()
|
|
}
|
|
// Open db it again
|
|
// It should restore the file(s) to
|
|
// 45, 45, 15
|
|
// with 3+3+1 items
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if f.items != 7 {
|
|
f.Close()
|
|
t.Fatalf("expected %d items, got %d", 7, f.items)
|
|
}
|
|
if err := assertFileSize(fileToCrop, 15); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
}
|
|
}
|
|
|
|
func TestFreezerTruncate(t *testing.T) {
|
|
|
|
t.Parallel()
|
|
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
fname := fmt.Sprintf("truncation-%d", rand.Uint64())
|
|
|
|
{ // Fill table
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 15 bytes 30 times
|
|
for x := 0; x < 30; x++ {
|
|
data := getChunk(15, x)
|
|
f.Append(uint64(x), data)
|
|
}
|
|
// The last item should be there
|
|
if _, err = f.Retrieve(f.items - 1); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
f.Close()
|
|
}
|
|
// Reopen, truncate
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
defer f.Close()
|
|
f.truncate(10) // 150 bytes
|
|
if f.items != 10 {
|
|
t.Fatalf("expected %d items, got %d", 10, f.items)
|
|
}
|
|
// 45, 45, 45, 15 -- bytes should be 15
|
|
if f.headBytes != 15 {
|
|
t.Fatalf("expected %d bytes, got %d", 15, f.headBytes)
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// TestFreezerRepairFirstFile tests a head file with the very first item only half-written.
|
|
// That will rewind the index, and _should_ truncate the head file
|
|
func TestFreezerRepairFirstFile(t *testing.T) {
|
|
t.Parallel()
|
|
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
fname := fmt.Sprintf("truncationfirst-%d", rand.Uint64())
|
|
{ // Fill table
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 80 bytes, splitting out into two files
|
|
f.Append(0, getChunk(40, 0xFF))
|
|
f.Append(1, getChunk(40, 0xEE))
|
|
// The last item should be there
|
|
if _, err = f.Retrieve(f.items - 1); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
f.Close()
|
|
}
|
|
// Truncate the file in half
|
|
fileToCrop := filepath.Join(os.TempDir(), fmt.Sprintf("%s.0001.rdat", fname))
|
|
{
|
|
if err := assertFileSize(fileToCrop, 40); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
file, err := os.OpenFile(fileToCrop, os.O_RDWR, 0644)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
file.Truncate(20)
|
|
file.Close()
|
|
}
|
|
// Reopen
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if f.items != 1 {
|
|
f.Close()
|
|
t.Fatalf("expected %d items, got %d", 0, f.items)
|
|
}
|
|
// Write 40 bytes
|
|
f.Append(1, getChunk(40, 0xDD))
|
|
f.Close()
|
|
// Should have been truncated down to zero and then 40 written
|
|
if err := assertFileSize(fileToCrop, 40); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
}
|
|
}
|
|
|
|
// TestFreezerReadAndTruncate tests:
|
|
// - we have a table open
|
|
// - do some reads, so files are open in readonly
|
|
// - truncate so those files are 'removed'
|
|
// - check that we did not keep the rdonly file descriptors
|
|
func TestFreezerReadAndTruncate(t *testing.T) {
|
|
t.Parallel()
|
|
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
fname := fmt.Sprintf("read_truncate-%d", rand.Uint64())
|
|
{ // Fill table
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 15 bytes 30 times
|
|
for x := 0; x < 30; x++ {
|
|
data := getChunk(15, x)
|
|
f.Append(uint64(x), data)
|
|
}
|
|
// The last item should be there
|
|
if _, err = f.Retrieve(f.items - 1); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
f.Close()
|
|
}
|
|
// Reopen and read all files
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 50, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if f.items != 30 {
|
|
f.Close()
|
|
t.Fatalf("expected %d items, got %d", 0, f.items)
|
|
}
|
|
for y := byte(0); y < 30; y++ {
|
|
f.Retrieve(uint64(y))
|
|
}
|
|
// Now, truncate back to zero
|
|
f.truncate(0)
|
|
// Write the data again
|
|
for x := 0; x < 30; x++ {
|
|
data := getChunk(15, ^x)
|
|
if err := f.Append(uint64(x), data); err != nil {
|
|
t.Fatalf("error %v", err)
|
|
}
|
|
}
|
|
f.Close()
|
|
}
|
|
}
|
|
|
|
func TestOffset(t *testing.T) {
|
|
t.Parallel()
|
|
rm, wm, sg := metrics.NewMeter(), metrics.NewMeter(), metrics.NewGauge()
|
|
fname := fmt.Sprintf("offset-%d", rand.Uint64())
|
|
{ // Fill table
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 40, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Write 6 x 20 bytes, splitting out into three files
|
|
f.Append(0, getChunk(20, 0xFF))
|
|
f.Append(1, getChunk(20, 0xEE))
|
|
|
|
f.Append(2, getChunk(20, 0xdd))
|
|
f.Append(3, getChunk(20, 0xcc))
|
|
|
|
f.Append(4, getChunk(20, 0xbb))
|
|
f.Append(5, getChunk(20, 0xaa))
|
|
f.printIndex()
|
|
f.Close()
|
|
}
|
|
// Now crop it.
|
|
{
|
|
// delete files 0 and 1
|
|
for i := 0; i < 2; i++ {
|
|
p := filepath.Join(os.TempDir(), fmt.Sprintf("%v.%04d.rdat", fname, i))
|
|
if err := os.Remove(p); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
}
|
|
// Read the index file
|
|
p := filepath.Join(os.TempDir(), fmt.Sprintf("%v.ridx", fname))
|
|
indexFile, err := os.OpenFile(p, os.O_RDWR, 0644)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
indexBuf := make([]byte, 7*indexEntrySize)
|
|
indexFile.Read(indexBuf)
|
|
|
|
// Update the index file, so that we store
|
|
// [ file = 2, offset = 4 ] at index zero
|
|
|
|
tailId := uint32(2) // First file is 2
|
|
itemOffset := uint32(4) // We have removed four items
|
|
zeroIndex := indexEntry{
|
|
offset: tailId,
|
|
filenum: itemOffset,
|
|
}
|
|
buf := zeroIndex.marshallBinary()
|
|
// Overwrite index zero
|
|
copy(indexBuf, buf)
|
|
// Remove the four next indices by overwriting
|
|
copy(indexBuf[indexEntrySize:], indexBuf[indexEntrySize*5:])
|
|
indexFile.WriteAt(indexBuf, 0)
|
|
// Need to truncate the moved index items
|
|
indexFile.Truncate(indexEntrySize * (1 + 2))
|
|
indexFile.Close()
|
|
|
|
}
|
|
// Now open again
|
|
{
|
|
f, err := newCustomTable(os.TempDir(), fname, rm, wm, sg, 40, true)
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
f.printIndex()
|
|
// It should allow writing item 6
|
|
f.Append(6, getChunk(20, 0x99))
|
|
|
|
// It should be fine to fetch 4,5,6
|
|
if got, err := f.Retrieve(4); err != nil {
|
|
t.Fatal(err)
|
|
} else if exp := getChunk(20, 0xbb); !bytes.Equal(got, exp) {
|
|
t.Fatalf("expected %x got %x", exp, got)
|
|
}
|
|
if got, err := f.Retrieve(5); err != nil {
|
|
t.Fatal(err)
|
|
} else if exp := getChunk(20, 0xaa); !bytes.Equal(got, exp) {
|
|
t.Fatalf("expected %x got %x", exp, got)
|
|
}
|
|
if got, err := f.Retrieve(6); err != nil {
|
|
t.Fatal(err)
|
|
} else if exp := getChunk(20, 0x99); !bytes.Equal(got, exp) {
|
|
t.Fatalf("expected %x got %x", exp, got)
|
|
}
|
|
|
|
// It should error at 0, 1,2,3
|
|
for i := 0; i < 4; i++ {
|
|
if _, err := f.Retrieve(uint64(i)); err == nil {
|
|
t.Fatal("expected err")
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// TODO (?)
|
|
// - test that if we remove several head-files, aswell as data last data-file,
|
|
// the index is truncated accordingly
|
|
// Right now, the freezer would fail on these conditions:
|
|
// 1. have data files d0, d1, d2, d3
|
|
// 2. remove d2,d3
|
|
//
|
|
// However, all 'normal' failure modes arising due to failing to sync() or save a file should be
|
|
// handled already, and the case described above can only (?) happen if an external process/user
|
|
// deletes files from the filesystem.
|