Параллельный метод асинхронного обратного вызова ввода-вывода

Я реализовал асинхронный ввод-вывод с обратным вызовом, когда я беспокоюсь о параллелизме. Я оспариваю вам это, так как я всегда работаю с одним и тем же файлом и файлом ОС физическое В основном, ввод-вывод является синхронной операцией, поэтому мне не понадобится механизм блокировки в моем методе обратного вызова — но я вполне могу ошибаться — введите SO: o) У меня есть менеджер буфера, который помещает прочитанные данные в свой буферный кеш когда операция чтения завершена, и механизм состояний для каждой перекрытой операции на основе состояний перечисления EOverlappedStates; «I / O не запущен», «Success» и «Error». Как вы думаете, мне нужно заблокировать метод обратного вызова для обеспечения параллелизма в многопоточной программе, такой как наша?

Открыть файл:

OS_FILE_HANDLE CUniformDiskInterface::OpenFile(const wchar_t *fileName, bool *fileExists, bool readData, bool writeData, bool overlap,
bool disableDiskCache, bool disableOsCache, bool randomAccess, bool sequentalScan) {
// Set access method
DWORD desiredAccess = readData ? GENERIC_READ : 0;
desiredAccess |= writeData ? GENERIC_WRITE : 0;

// Set file flags
DWORD fileFlags = disableDiskCache ? FILE_FLAG_WRITE_THROUGH : 0;
fileFlags |= disableOsCache ? FILE_FLAG_NO_BUFFERING : 0;
fileFlags |= randomAccess ? FILE_FLAG_RANDOM_ACCESS : 0;
fileFlags |= sequentalScan ? FILE_FLAG_SEQUENTIAL_SCAN : 0;
fileFlags |= !fileFlags ? FILE_ATTRIBUTE_NORMAL : 0;
fileFlags |= overlap ? FILE_FLAG_OVERLAPPED : 0;

HANDLE hOutputFile = CreateFile(
fileName,
desiredAccess,
0,
NULL,
OPEN_EXISTING,
fileFlags,
NULL);

Читать файл:

_UINT64 CUniformDiskInterface::ReadFromFile(OS_FILE_HANDLE hFile, void *outData, _UINT64 bytesToRead, OVERLAPPED *overlapped, LPOVERLAPPED_COMPLETION_ROUTINE completionRoutine) {
DWORD wBytesRead = 0;

BOOL result = completionRoutine ?
ReadFileEx(hFile, outData, (DWORD)(bytesToRead), overlapped, completionRoutine) :
ReadFile(hFile, outData, (DWORD)(bytesToRead), &wBytesRead, overlapped);

if (!result)
{
int errorCode = GetLastError();
if (errorCode != ERROR_IO_PENDING )
{
wstringstream err(wstringstream::in | wstringstream::out);
err << L"Can't read sectors from file. [ReadFile] error #" << errorCode << L".";
throw new FileIOException(L"CUniformDiskInterface", L"ReadFromFile", err.str().c_str(), GETDATE, GETFILE, GETLINE);
}
}

return (_UINT64)wBytesRead; }

Расширенная перекрывающаяся структура:

            /*!
\enum EOverlappedStates
\brief The different overlapped states
\details Used as inter-thread communication while waiting for the I/O operation to complete
*/
enum EOverlappedStates
{
/** The I/O operation has not started or in in-progress */
EOverlappedNotStarted,

/** The I/O operation is done and was successful */
EOverlappedSuccess,

/** The I/O operation is done but there was an error */
EOverlappedError
};

/*!
\struct OverlappedEx
\brief Extended overlapped structure
*/
struct OverlappedEx : OVERLAPPED
{
/** The buffer manager that is designated to cache the record when it's loaded */
CBufferManager *bufferManger;

/** Transaction ID related to this disk I/O operation */
_UINT64 transactionId;

/** Start disk sector of the record */
_UINT64 startDiskSector;

/** Buffer */
void *buffer;

/** Number of bytes in \c buffer */
_UINT64 bufferSize;

/** Current overlapped I/O state. Used for inter-thread communication while waiting for the I/O to complete */
EOverlappedStates state;

/** Error code, or \c 0 if no error */
_UINT32 errorCode;
};

Метод обратного вызова:

    /*! \brief Callback routine after a overlapped read has completed
\details Fills the buffer managers buffer cache with the read data
\todo This callback method may be a bottleneck, so look into how to handle this better
*/
VOID WINAPI CompletedReadRoutine(DWORD dwErr, DWORD cbBytesRead, LPOVERLAPPED lpOverLap)
{
OverlappedEx *overlapped = (OverlappedEx*)lpOverLap;
overlapped->errorCode = (_UINT32)dwErr;

if (!dwErr && cbBytesRead)
{
overlapped->state = EOverlappedSuccess;
overlapped->bufferManger->AddBuffer(overlapped->startDiskSector, overlapped->buffer, overlapped->bufferSize);
}
else
{
// An error occurred
overlapped->state = EOverlappedError;
}
}

Использование:

    _UINT64 startDiskSector = location / sectorByteSize;
void *buffer = bufferManager->GetBuffer(startDiskSector);
if (!buffer)
{
/*
The disk sector was not cached, so get the data from the disk and cache in internal memory with
the buffer manager
*/
buffer = new char[recordByteSize];

// Create a overlapped structure to enable disk async I/O operations
OverlappedEx *overlapped = new OverlappedEx;
memset(overlapped, 0, sizeof(OverlappedEx));
overlapped->Offset = (DWORD)(startDiskSector & 0xffffffffULL);
overlapped->OffsetHigh = (DWORD)(startDiskSector >> 31ULL);
overlapped->hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
overlapped->bufferManger = bufferManager;
overlapped->startDiskSector = startDiskSector;
overlapped->buffer = buffer;
overlapped->bufferSize = recordByteSize;
overlapped->state = EOverlappedNotStarted;

// Read from disk
diskApi.ReadFromFile(fileHandle, buffer, sectorByteSize, overlapped, CompletedReadRoutine);
return overlapped;
}