从 WriteFile 到物理磁盘的访问被拒绝错误，win7

我正在尝试将一些数据从特定的物理扇区写入 SD 卡。我从一家公司收到了执行此操作的代码，他们说它在 windows-xp 上工作正常。这与以下情况相同Win Vista/7 下的 WriteFile 错误 #5“拒绝访问”
这是将数据写入 SD 卡的部分（在我的 cae drv 值为“F”）。从其他人那里读到，我添加了锁定和卸载，但锁定失败（并且也卸载）。我对windows编程不太熟悉。谁能告诉我这段代码有什么问题吗？谢谢你的帮助。 （顺便说一句，我正在锁定 3GiB）

u32 HDD_write(u8 drv, u32 SecAddr, u32 blocks, u8 *buf) 
{
  u32 ret = 0;
  u32 ldistanceLow, ldistanceHigh, dwpointer, bytestoread, numread;
  char cur_drv[100];
  HANDLE g_hDevice;

  sprintf(cur_drv, "\\\\.\\%c:",drv); // , (u32)drv);
  g_hDevice = CreateFile(cur_drv, GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

  if(g_hDevice == INVALID_HANDLE_VALUE)
    return 0;

  // lock and dismount
  ret = LockFile(g_hDevice, 0, 0, 3 * 1023 * 1023 * 1023, 0);
  printf("ret = %d", ret);
  DeviceIoControl(g_hDevice, FSCTL_DISMOUNT_VOLUME, NULL, 0, NULL, 0, NULL, NULL);
  printf("error = %d", GetLastError());

  ldistanceLow = SecAddr << 9;
  ldistanceHigh = SecAddr >> (32-9);
  dwpointer = SetFilePointer(g_hDevice, ldistanceLow, (long *)&ldistanceHigh, FILE_BEGIN);

  if(dwpointer != 0xFFFFFFFF) {
    bytestoread = blocks * 512;
    ret = WriteFile(g_hDevice, buf, bytestoread, (unsigned long *)&numread, NULL);
    if(ret)   ret = 1;
    else      {
        ret = 0;
        printf("error = %d", GetLastError());
    }
  }

  CloseHandle(g_hDevice);
  return ret;
}

我几天前解决了这个问题，忘记在这里检查我的问题。 这是我使用的代码。创建文件时（对于分区磁盘），块设备也需要 GENERIC_READ。而且钥匙是先卸后锁。

u32 HDD_write(u8 drv, u32 SecAddr, u32 blocks, u8 *buf) {
  u32 ret = 0;
  u32 ldistanceLow, ldistanceHigh, dwpointer, bytestoread, numread;
  char cur_drv[100];
  HANDLE g_hDevice;
  DWORD status;

  //sprintf(cur_drv, "\\\\.\\PhysicalDrive%d", drv);
  sprintf(cur_drv, "\\\\.\\%c:",drv);
  g_hDevice = CreateFile(cur_drv, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

  if(g_hDevice == INVALID_HANDLE_VALUE)
    return 0;

// dismout and lock added by ckim

  if (!DeviceIoControl(g_hDevice, FSCTL_DISMOUNT_VOLUME,
      NULL, 0, NULL, 0, &status, NULL))
  {
      DWORD err = GetLastError();
      printf("Error %d attempting to dismount volume, error code\n",err);
  }

  // lock volume
  if (!DeviceIoControl(g_hDevice, FSCTL_LOCK_VOLUME,
      NULL, 0, NULL, 0, &status, NULL))
  {
      printf("Error %d attempting to lock device\n", GetLastError());
  }

  ldistanceLow = SecAddr << 9;
  ldistanceHigh = SecAddr >> (32-9);
  dwpointer = SetFilePointer(g_hDevice, ldistanceLow, (long *)&ldistanceHigh, FILE_BEGIN);

  if(dwpointer != 0xFFFFFFFF) {
    bytestoread = blocks * 512;
    ret = WriteFile(g_hDevice, buf, bytestoread, (unsigned long *)&numread, NULL);
    if(ret)   ret = 1;
    else      {
        ret = 0;
        printf("error = %d", GetLastError());
    }
  }

  CloseHandle(g_hDevice);
  return ret;
}