c++ - DeviceIoControl 返回意外的物理扇区大小

Question

我使用 DeviceIoControl 返回物理磁盘扇区的大小。它总是返回 512 个字节，直到最近它开始返回 4096 个字节。检查生成的 STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR 我发现逻辑和物理字节大小已经调换了位置 - 磁盘扇区的逻辑字节大小不应该总是大于或等于物理扇区大小吗？

#include <Windows.h>
#include <iostream>
#include <Windows.h>

#pragma comment(lib, "Kernel32.lib")

int main()
{
    HANDLE hDevice;

    char cDisk = 'c';   // Get metadata about the C:\ disk

    // Build the logical drive path and get the drive device handle
    std::wstring logicalDrive = L"\\\\.\\";
    wchar_t drive[3];
    drive[0] = cDisk;
    drive[1] = L':';
    drive[2] = L'\0';
    logicalDrive.append(drive);

    hDevice = CreateFile(
        logicalDrive.c_str(),
        0, 
        0,
        NULL,
        OPEN_EXISTING,
        0,
        NULL);

    if (hDevice == INVALID_HANDLE_VALUE)
    {
        std::cerr << "Error\n";
        return -1;
    }   

    // Now that we have the device handle for the disk, let us get disk's metadata
    DWORD outsize;
    STORAGE_PROPERTY_QUERY storageQuery;
    memset(&storageQuery, 0, sizeof(STORAGE_PROPERTY_QUERY));
    storageQuery.PropertyId = StorageAccessAlignmentProperty;
    storageQuery.QueryType  = PropertyStandardQuery;

    STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR diskAlignment = {0};
    memset(&diskAlignment, 0, sizeof(STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR));

    if (!DeviceIoControl(hDevice, 
        IOCTL_STORAGE_QUERY_PROPERTY, 
        &storageQuery, 
        sizeof(STORAGE_PROPERTY_QUERY), 
        &diskAlignment,
        sizeof(STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR), 
        &outsize,
        NULL)
        )
    {
        std::cerr << "Error\n";
        return -1;
    }

    std::cout << "Physical sector size: " diskAlignment.BytesPerPhysicalSector << std::endl;
    std::cout << "Logical sector size: " diskAlignment.BytesPerLogicalSector << std::endl;

    return 0;
}

运行上述代码的结果是:

Physical sector size: 4096
Logical sector size: 512

运行 fsutil 会得到同样的意外结果。

C:\WINDOWS\system32>fsutil fsinfo ntfsinfo c:
NTFS Version   :                  3.1
LFS Version    :                  2.0
Number Sectors :                  0x000000001741afff
Total Clusters :                  0x0000000002e835ff
Free Clusters  :                  0x0000000000999d28
Total Reserved :                  0x0000000000003260
Bytes Per Sector  :               512
Bytes Per Physical Sector :       4096
Bytes Per Cluster :               4096
Bytes Per FileRecord Segment    : 1024
Clusters Per FileRecord Segment : 0

我做错了什么？

Answer 1

这里没有错。来自 MSDN 的“文件缓冲”一文:

Application developers should take note of new types of storage devices being introduced into the market with a physical media sector size of 4,096 bytes. The industry name for these devices is "Advanced Format". As there may be compatibility issues with directly introducing 4,096 bytes as the unit of addressing for the media, a temporary compatibility solution is to introduce devices that emulate a regular 512-byte sector storage device but make available information about the true sector size through standard ATA and SCSI commands. As a result of this emulation, there are in essence two sector sizes that developers will need to understand:

• Logical Sector: The unit that is used for logical block addressing for the media. We can also think of it as the smallest unit of write
  that the storage can accept. This is the "emulation".
• Physical Sector: The unit for which read and write operations to the device are completed in a single operation. This is the unit of atomic write, and what unbuffered I/O will need to be aligned to in
  order to have optimal performance and reliability characteristics.