SetVolumeMountPoint return fail with error 87 Why ?

Gova_Gimer · November 5, 2021, 9:57pm

Hello,
I developped my virtualdisk and the function setvolumemountpoint fail with error 87.
The ioctl function ‘IOCTL_MOUNTDEV_QUERY_DEVICE_NAME’ return the name of my driver.
Can you help please ?

Sample code user debugging :

* 1. HANDLE hDevice;

1. ```
    wchar_t  szDeviceName[512];
```

    wcscpy_s(szDeviceName,L"\\\\?\\Volume{cd4cfca8-484c-8042-550e-916f0206fb8f}");

1. ```
    BYTE byBuffer[1024];
```
1. ```
    PMOUNTDEV_NAME pMountDevName;
```

     hDevice = CreateFile(szDeviceName, FILE_GENERIC_READ | FILE_GENERIC_WRITE,

        FILE_SHARE_READ | FILE_SHARE_WRITE,

1. ```
        NULL, OPEN_EXISTING, 0, NULL);
```

    if (hDevice == INVALID_HANDLE_VALUE)

1. ```
        return 1;
```
1. ```
    ULONGLONG lw = 0;
```
1. ```
    DWORD cbBytesReturned = 0;
```
1. ```
    int err;
```
1. ```
    DISK_GEOMETRY diskg;
```

        BOOL bSuccess = DeviceIoControl(hDevice,

            IOCTL_DISK_UPDATE_DRIVE_SIZE,

1. ```
            NULL, 0,
```

            (LPVOID)&diskg, sizeof(diskg),//sizeof(byBuffer),

1. ```
            &cbBytesReturned,
```
1. ```
            (LPOVERLAPPED)NULL);
```
1. ```
        err = GetLastError();
```

         bSuccess = DeviceIoControl(hDevice,

            IOCTL_DISK_GET_LENGTH_INFO,

1. ```
            NULL, 0,
```

            (LPVOID)&lw, 8,//sizeof(byBuffer),

1. ```
            &cbBytesReturned,
```
1. ```
            (LPOVERLAPPED)NULL);
```
1. ```
         err = GetLastError();
```

         STORAGE_DEVICE_NUMBER storageDeviceNumber;

         bSuccess = DeviceIoControl(hDevice,

             IOCTL_STORAGE_GET_DEVICE_NUMBER,

1. ```
             NULL, 0,
```

             (LPVOID)&storageDeviceNumber, sizeof(storageDeviceNumber),//sizeof(byBuffer),

1. ```
             &cbBytesReturned,
```
1. ```
             (LPOVERLAPPED)NULL);
```
1. ```
         err = GetLastError();
```

         PARTITION_INFORMATION_EX ts = { 0 };

             bSuccess = DeviceIoControl(hDevice,

                 IOCTL_DISK_GET_PARTITION_INFO_EX,

1. ```
                 NULL, 0,
```

                 (LPVOID)&ts, sizeof(ts),//sizeof(byBuffer),

1. ```
                 &cbBytesReturned,
```
1. ```
                 (LPOVERLAPPED)NULL);
```
1. ```
             err = GetLastError();
```

    bSuccess = DeviceIoControl(hDevice,

        IOCTL_MOUNTDEV_QUERY_DEVICE_NAME,

1. ```
        NULL, 0,
```

        (LPVOID)byBuffer,100,//sizeof(byBuffer),

1. ```
        &cbBytesReturned,
```
1. ```
        (LPOVERLAPPED)NULL);
```
1. ```
    err = GetLastError();
```

    pMountDevName = (PMOUNTDEV_NAME)byBuffer;

    printf("\n%.*ls\n", pMountDevName->NameLength / sizeof(WCHAR),

1. ```
        pMountDevName->Name);
```
1. ```
    bSuccess = CloseHandle(hDevice);
```

code for mounting drive into empty directory which fail with error 87.

1. wcscpy_s(szUniqueVolumeName, L"\\?\Volume{cd4cfca8-484c-8042-550e-916f0206fb8f}\");

    BOOL b=SetVolumeMountPoint(L"c:\\mnt2\\", szUniqueVolumeName);

The name volume disk is correct THEN why SetVolumeMountPoint don’t work !.

Thank for solve this problem !