How to get allocated blocks for VHDx? queryChangesVirtualDisk gives ACCESS DENIED.
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I am trying out VirtualDisk APIs, So far I am able to Open a VHDX file, get some of the properties by using GetVirtualDiskInformation. But I am not able to get RCT information and ChangedAreas. 1)Opendisk is done with VIRTUAL_DISK_ACCESS_GET_INFO flag. 2)GetVirtualDiskInformation a. Works fine when version flag is set to GET_VIRTUAL_DISK_INFO_SIZE, able to fetch sector size and other information b. Gives ERROR_INSUFFICIENT_BUFFER(122) when version flag is set to GET_VIRTUAL_DISK_INFO_CHANGE_TRACKING_STATE to access diskInfo->ChangeTrackingState.MostRecentId
PGET\_VIRTUAL\_DISK\_INFO diskInfo; ULONG diskInfoSize = sizeof(GET\_VIRTUAL\_DISK\_INFO); std::wcout << "size of diskinfo structure " << diskInfoSize << std::endl; diskInfo = (PGET\_VIRTUAL\_DISK\_INFO)malloc(diskInfoSize); diskInfo->Version = GET\_VIRTUAL\_DISK\_INFO\_SIZE; res = GetVirtualDiskInformation(vhdHandle, &diskInfoSize, diskInfo, NULL); long physicalSize = diskInfo->Size.PhysicalSize; long virtualSize = diskInfo->Size.VirtualSize; long sectorSize = diskInfo->Size.SectorSize; long blockSize = diskInfo->Size.BlockSize; std::wcout << "physicalSize :" << physicalSize << std::endl; std::wcout << "virtualSize :" << virtualSize << std::endl; std::wcout << "sectorSize :" << sectorSize << std::endl; std::wcout << "blockSize :" << blockSize << std::endl; diskInfo->Version = GET\_VIRTUAL\_DISK\_INFO\_CHANGE\_TRACKING\_STATE; res = GetVirtualDiskInformation(vhdHandle, &diskInfoSize, diskInfo, NULL); std::wcout << "\\nrct id:" << diskInfo->ChangeTrackingState.MostRecentId << std::endl;3)queryChangesVirtualDisk gives ACCESS DENIED.
ULONG64 byteOffset = 0L; ULONG64 byteLength = 19327352832; QUERY\_CHANGES\_VIRTUAL\_DISK\_RANGE\* changedAreas = NULL; ULONG rangeCount = 0L; ULONG64 processedLength = 0L; res = QueryChangesVirtualDisk(vhdHandle, "rctX:c2eb01d9:ccb1:405d:acb6:f0e76d055906:00000001", byteOffset, byteLength, QUERY\_CHANGES\_VIRTUAL\_DISK\_FLAG\_NONE, changedAreas, &rangeCount, &processedLength);Can someone please give some ideas on what I am doing wrong?
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I am trying out VirtualDisk APIs, So far I am able to Open a VHDX file, get some of the properties by using GetVirtualDiskInformation. But I am not able to get RCT information and ChangedAreas. 1)Opendisk is done with VIRTUAL_DISK_ACCESS_GET_INFO flag. 2)GetVirtualDiskInformation a. Works fine when version flag is set to GET_VIRTUAL_DISK_INFO_SIZE, able to fetch sector size and other information b. Gives ERROR_INSUFFICIENT_BUFFER(122) when version flag is set to GET_VIRTUAL_DISK_INFO_CHANGE_TRACKING_STATE to access diskInfo->ChangeTrackingState.MostRecentId
PGET\_VIRTUAL\_DISK\_INFO diskInfo; ULONG diskInfoSize = sizeof(GET\_VIRTUAL\_DISK\_INFO); std::wcout << "size of diskinfo structure " << diskInfoSize << std::endl; diskInfo = (PGET\_VIRTUAL\_DISK\_INFO)malloc(diskInfoSize); diskInfo->Version = GET\_VIRTUAL\_DISK\_INFO\_SIZE; res = GetVirtualDiskInformation(vhdHandle, &diskInfoSize, diskInfo, NULL); long physicalSize = diskInfo->Size.PhysicalSize; long virtualSize = diskInfo->Size.VirtualSize; long sectorSize = diskInfo->Size.SectorSize; long blockSize = diskInfo->Size.BlockSize; std::wcout << "physicalSize :" << physicalSize << std::endl; std::wcout << "virtualSize :" << virtualSize << std::endl; std::wcout << "sectorSize :" << sectorSize << std::endl; std::wcout << "blockSize :" << blockSize << std::endl; diskInfo->Version = GET\_VIRTUAL\_DISK\_INFO\_CHANGE\_TRACKING\_STATE; res = GetVirtualDiskInformation(vhdHandle, &diskInfoSize, diskInfo, NULL); std::wcout << "\\nrct id:" << diskInfo->ChangeTrackingState.MostRecentId << std::endl;3)queryChangesVirtualDisk gives ACCESS DENIED.
ULONG64 byteOffset = 0L; ULONG64 byteLength = 19327352832; QUERY\_CHANGES\_VIRTUAL\_DISK\_RANGE\* changedAreas = NULL; ULONG rangeCount = 0L; ULONG64 processedLength = 0L; res = QueryChangesVirtualDisk(vhdHandle, "rctX:c2eb01d9:ccb1:405d:acb6:f0e76d055906:00000001", byteOffset, byteLength, QUERY\_CHANGES\_VIRTUAL\_DISK\_FLAG\_NONE, changedAreas, &rangeCount, &processedLength);Can someone please give some ideas on what I am doing wrong?
Hi, I do see at least one problem in your code:
ULONG diskInfoSize = sizeof(GET_VIRTUAL_DISK_INFO);
should be changed to:
ULONG diskInfoSize = sizeof(GET_VIRTUAL_DISK_INFO) + sizeof(GUID);
cazorla19 wrote:
queryChangesVirtualDisk gives ACCESS DENIED.
Could you show me the flags you are passing to OpenVirtualDisk? Best Wishes, -David Delaune
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Hi, I do see at least one problem in your code:
ULONG diskInfoSize = sizeof(GET_VIRTUAL_DISK_INFO);
should be changed to:
ULONG diskInfoSize = sizeof(GET_VIRTUAL_DISK_INFO) + sizeof(GUID);
cazorla19 wrote:
queryChangesVirtualDisk gives ACCESS DENIED.
Could you show me the flags you are passing to OpenVirtualDisk? Best Wishes, -David Delaune
Hi David, I have tried OpenVirtualDisk with VIRTUAL_DISK_ACCESS_GET_INFO as suggested in msdn portal. I also tried with VIRTUAL_DISK_ACCESS_READ, both times I got same error.
OPEN\_VIRTUAL\_DISK\_PARAMETERS openParameters; openParameters.Version = OPEN\_VIRTUAL\_DISK\_VERSION\_1; openParameters.Version1.RWDepth = OPEN\_VIRTUAL\_DISK\_RW\_DEPTH\_DEFAULT; \_VIRTUAL\_STORAGE\_TYPE storageType; storageType.DeviceId = VIRTUAL\_STORAGE\_TYPE\_DEVICE\_UNKNOWN; storageType.VendorId = VIRTUAL\_STORAGE\_TYPE\_VENDOR\_UNKNOWN;DWORD res = OpenVirtualDisk(&storageType, path,
VIRTUAL_DISK_ACCESS_GET_INFO,
OPEN_VIRTUAL_DISK_FLAG_NONE,
&openParameters,
&vhdHandle);Also, I changed diskInfoSize as suggested but still got the same 'insufficient buffer size' error.
ULONG diskInfoSize = sizeof(GET_VIRTUAL_DISK_INFO) + sizeof(GUID);
Increasing the diskinfo size definitely helped me in getting rct id using GetVirtualDiskInformation,
WCHAR changeTrackingInfo\[2048\]; ZeroMemory(changeTrackingInfo, sizeof(changeTrackingInfo)); PGET\_VIRTUAL\_DISK\_INFO diskInfo; ULONG diskInfoSize = sizeof(GET\_VIRTUAL\_DISK\_INFO) + sizeof(changeTrackingInfo);queryChangesVirtualDisk gives ACCESS DENIED is not resolved. Regards, Hari
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Quote:
This value is not supported before Windows 10 and Windows Server 2016.
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it. ― Confucian Analects: Rules of Confucius about his food
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Hi Gerry, I am trying in a Windows2016 hyperV, and guest VM has windows 10. Also, I am able to get changed blocks by using WMI queries. But VHD API is giving ACCESS_DENIED_ERROR. Regards, Hari
The first thing I'd do is confirm "without" a VM. And then I'd try Oracle's VmBox. Then try running as "admin" in the VM, etc.
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it. ― Confucian Analects: Rules of Confucius about his food
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Hi David, I have tried OpenVirtualDisk with VIRTUAL_DISK_ACCESS_GET_INFO as suggested in msdn portal. I also tried with VIRTUAL_DISK_ACCESS_READ, both times I got same error.
OPEN\_VIRTUAL\_DISK\_PARAMETERS openParameters; openParameters.Version = OPEN\_VIRTUAL\_DISK\_VERSION\_1; openParameters.Version1.RWDepth = OPEN\_VIRTUAL\_DISK\_RW\_DEPTH\_DEFAULT; \_VIRTUAL\_STORAGE\_TYPE storageType; storageType.DeviceId = VIRTUAL\_STORAGE\_TYPE\_DEVICE\_UNKNOWN; storageType.VendorId = VIRTUAL\_STORAGE\_TYPE\_VENDOR\_UNKNOWN;DWORD res = OpenVirtualDisk(&storageType, path,
VIRTUAL_DISK_ACCESS_GET_INFO,
OPEN_VIRTUAL_DISK_FLAG_NONE,
&openParameters,
&vhdHandle);Also, I changed diskInfoSize as suggested but still got the same 'insufficient buffer size' error.
ULONG diskInfoSize = sizeof(GET_VIRTUAL_DISK_INFO) + sizeof(GUID);
Increasing the diskinfo size definitely helped me in getting rct id using GetVirtualDiskInformation,
WCHAR changeTrackingInfo\[2048\]; ZeroMemory(changeTrackingInfo, sizeof(changeTrackingInfo)); PGET\_VIRTUAL\_DISK\_INFO diskInfo; ULONG diskInfoSize = sizeof(GET\_VIRTUAL\_DISK\_INFO) + sizeof(changeTrackingInfo);queryChangesVirtualDisk gives ACCESS DENIED is not resolved. Regards, Hari
Hi Hari, Kinda looks like you are breaking the rules of nearly everything in the Remarks section for the OpenVirtualDisk function for a permanently attached virtual disk. This is working for me, code is ugly, there is no error handling... it's just a code sample:
#include
#include
#include
#include
#include
#include
#include#pragma comment(lib, "wbemuuid.lib")
#pragma comment(lib, "virtdisk.lib")const GUID VIRTUAL_STORAGE_TYPE_VENDOR_MICROSOFT = {0xec984aec, 0xa0f9, 0x47e9, 0x90, 0x1f, 0x71, 0x41, 0x5a, 0x66, 0x34, 0x5b};
const GUID VIRTUAL_STORAGE_TYPE_VENDOR_UNKNOWN = { 0x00000000, 0x0000, 0x0000, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };int main()
{
HANDLE vhdHandle = NULL;
VIRTUAL_STORAGE_TYPE storageType = {};
ULONG status = 0L;//storageType.DeviceId = VIRTUAL\_STORAGE\_TYPE\_DEVICE\_VHDX; //storageType.VendorId = VIRTUAL\_STORAGE\_TYPE\_VENDOR\_MICROSOFT; storageType.DeviceId = VIRTUAL\_STORAGE\_TYPE\_DEVICE\_UNKNOWN; storageType.VendorId = VIRTUAL\_STORAGE\_TYPE\_VENDOR\_UNKNOWN; PCWSTR virtualDiskPath = L"D:\\\\VirtualMachines\\\\x64\_Windows8.1\\\\x64\_Windows8.1\\\\Virtual Hard Disks\\\\x64\_Windows8.1.vhdx"; OPEN\_VIRTUAL\_DISK\_PARAMETERS\* pOpenParameter = NULL; status = OpenVirtualDisk(&storageType, virtualDiskPath,VIRTUAL\_DISK\_ACCESS\_ATTACH\_RW | VIRTUAL\_DISK\_ACCESS\_GET\_INFO | VIRTUAL\_DISK\_ACCESS\_DETACH,OPEN\_VIRTUAL\_DISK\_FLAG\_NONE, pOpenParameter, &vhdHandle); if (ERROR\_SUCCESS == status) { DWORD sizeUsed = GET\_VIRTUAL\_DISK\_INFO\_SIZE; WCHAR changeTrackingInfo\[sizeof(GET\_VIRTUAL\_DISK\_INFO) + sizeof(GUID)\]; ::ZeroMemory(changeTrackingInfo, sizeof(changeTrackingInfo)); PGET\_VIRTUAL\_DISK\_INFO virtualDiskInfo = (GET\_VIRTUAL\_DISK\_INFO\*)changeTrackingInfo; virtualDiskInfo->Version = (GET\_VIRTUAL\_DISK\_INFO\_VERSION)GET\_VIRTUAL\_DISK\_INFO\_CHANGE\_TRACKING\_STATE; ULONG virtualDiskInfoSize = sizeof(changeTrackingInfo); status = GetVirtualDiskInformation(vhdHandle, &virtualDiskInfoSize, virtualDiskInfo, &sizeUsed); if (ERROR\_SUCCESS == status) { ULONG64 virtualDiskSize = virtualDiskInfo->Size.VirtualSize; printf("Disk Infomation:\\n"); GUID virtualDiskGuid = virtualDiskInfo->Identifier; wchar\_t szGUID\[64\] = { 0 }; StringFromGUID2(virtualDiskGuid, szGUID, 64); wprintf(L"ChangeTrackingState.Enabled:%d\\n", vi -
Hi Hari, Kinda looks like you are breaking the rules of nearly everything in the Remarks section for the OpenVirtualDisk function for a permanently attached virtual disk. This is working for me, code is ugly, there is no error handling... it's just a code sample:
#include
#include
#include
#include
#include
#include
#include#pragma comment(lib, "wbemuuid.lib")
#pragma comment(lib, "virtdisk.lib")const GUID VIRTUAL_STORAGE_TYPE_VENDOR_MICROSOFT = {0xec984aec, 0xa0f9, 0x47e9, 0x90, 0x1f, 0x71, 0x41, 0x5a, 0x66, 0x34, 0x5b};
const GUID VIRTUAL_STORAGE_TYPE_VENDOR_UNKNOWN = { 0x00000000, 0x0000, 0x0000, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };int main()
{
HANDLE vhdHandle = NULL;
VIRTUAL_STORAGE_TYPE storageType = {};
ULONG status = 0L;//storageType.DeviceId = VIRTUAL\_STORAGE\_TYPE\_DEVICE\_VHDX; //storageType.VendorId = VIRTUAL\_STORAGE\_TYPE\_VENDOR\_MICROSOFT; storageType.DeviceId = VIRTUAL\_STORAGE\_TYPE\_DEVICE\_UNKNOWN; storageType.VendorId = VIRTUAL\_STORAGE\_TYPE\_VENDOR\_UNKNOWN; PCWSTR virtualDiskPath = L"D:\\\\VirtualMachines\\\\x64\_Windows8.1\\\\x64\_Windows8.1\\\\Virtual Hard Disks\\\\x64\_Windows8.1.vhdx"; OPEN\_VIRTUAL\_DISK\_PARAMETERS\* pOpenParameter = NULL; status = OpenVirtualDisk(&storageType, virtualDiskPath,VIRTUAL\_DISK\_ACCESS\_ATTACH\_RW | VIRTUAL\_DISK\_ACCESS\_GET\_INFO | VIRTUAL\_DISK\_ACCESS\_DETACH,OPEN\_VIRTUAL\_DISK\_FLAG\_NONE, pOpenParameter, &vhdHandle); if (ERROR\_SUCCESS == status) { DWORD sizeUsed = GET\_VIRTUAL\_DISK\_INFO\_SIZE; WCHAR changeTrackingInfo\[sizeof(GET\_VIRTUAL\_DISK\_INFO) + sizeof(GUID)\]; ::ZeroMemory(changeTrackingInfo, sizeof(changeTrackingInfo)); PGET\_VIRTUAL\_DISK\_INFO virtualDiskInfo = (GET\_VIRTUAL\_DISK\_INFO\*)changeTrackingInfo; virtualDiskInfo->Version = (GET\_VIRTUAL\_DISK\_INFO\_VERSION)GET\_VIRTUAL\_DISK\_INFO\_CHANGE\_TRACKING\_STATE; ULONG virtualDiskInfoSize = sizeof(changeTrackingInfo); status = GetVirtualDiskInformation(vhdHandle, &virtualDiskInfoSize, virtualDiskInfo, &sizeUsed); if (ERROR\_SUCCESS == status) { ULONG64 virtualDiskSize = virtualDiskInfo->Size.VirtualSize; printf("Disk Infomation:\\n"); GUID virtualDiskGuid = virtualDiskInfo->Identifier; wchar\_t szGUID\[64\] = { 0 }; StringFromGUID2(virtualDiskGuid, szGUID, 64); wprintf(L"ChangeTrackingState.Enabled:%d\\n", viMany thanks for your inputs. Tried your sample code in my environment, OpenVirtualDisk failed with 32 ERROR_SHARING_VIOLATION. Steps I have followed till now, 1. Create a production snapshot on the VM. 2. Convert the snapshot to the reference point(snapshot gets merged automatically) using wmi commands. 3. Added some files to VM disk. 4. Create another production snapshot on the VM so that any changes in VM will be written to avhdx file. 5. Try to open the parent vhdx using VHD APIs. 6. Get a resilient change tracking identifier using ChangeTrackingState.MostRecentId 7. Query for changed areas using VHD API QueryChangesVirtualDisk. So far I am able to get till step six by passing only VIRTUAL_DISK_ACCESS_GET_INFO flag for OpenVirtualDisk. step 7 gives ACCESS_DENIED.
void openDiskEx()
{
HANDLE vhdHandle = NULL;
VIRTUAL_STORAGE_TYPE storageType = {};
ULONG status = 0L;storageType.DeviceId = VIRTUAL\_STORAGE\_TYPE\_DEVICE\_UNKNOWN; storageType.VendorId = VIRTUAL\_STORAGE\_TYPE\_VENDOR\_UNKNOWN; PCWSTR virtualDiskPath = L"C:\\\\Hyper-V\\\\Virtual Hard Disks\\\\Lacazette\\\\Windows2016.vhdx"; OPEN\_VIRTUAL\_DISK\_PARAMETERS\* pOpenParameter = NULL; status = OpenVirtualDisk(&storageType, virtualDiskPath, VIRTUAL\_DISK\_ACCESS\_ATTACH\_RW | VIRTUAL\_DISK\_ACCESS\_GET\_INFO | VIRTUAL\_DISK\_ACCESS\_DETACH, OPEN\_VIRTUAL\_DISK\_FLAG\_NONE, pOpenParameter, &vhdHandle); std::cout << "opendisk:" << status<< std::endl; if (ERROR\_SUCCESS == status) { DWORD sizeUsed = GET\_VIRTUAL\_DISK\_INFO\_SIZE; WCHAR changeTrackingInfo\[sizeof(GET\_VIRTUAL\_DISK\_INFO) + sizeof(GUID)\]; ::ZeroMemory(changeTrackingInfo, sizeof(changeTrackingInfo)); PGET\_VIRTUAL\_DISK\_INFO virtualDiskInfo = (GET\_VIRTUAL\_DISK\_INFO\*)changeTrackingInfo; virtualDiskInfo->Version = (GET\_VIRTUAL\_DISK\_INFO\_VERSION)GET\_VIRTUAL\_DISK\_INFO\_CHANGE\_TRACKING\_STATE; ULONG virtualDiskInfoSize = sizeof(changeTrackingInfo); status = GetVirtualDiskInformation(vhdHandle, &virtualDiskInfoSize, virtualDiskInfo, &sizeUsed); std::cout << "GetVirtualDiskInformation:" << status << std::endl; if (ERROR\_SUCCESS == status) { ULONG64 virtualDiskSize = virtualDiskInfo->Size.VirtualSize; printf("Disk Infomation:\\n"); GUID virtualDiskGuid = virtualDiskInfo->Identifier; wchar\_t szGUID\[64\] = { 0 }; StringFromGUID2(virtualDiskGuid, szGUID, 64); wprintf(L"ChangeTrackingState.Enabled:%d -
Many thanks for your inputs. Tried your sample code in my environment, OpenVirtualDisk failed with 32 ERROR_SHARING_VIOLATION. Steps I have followed till now, 1. Create a production snapshot on the VM. 2. Convert the snapshot to the reference point(snapshot gets merged automatically) using wmi commands. 3. Added some files to VM disk. 4. Create another production snapshot on the VM so that any changes in VM will be written to avhdx file. 5. Try to open the parent vhdx using VHD APIs. 6. Get a resilient change tracking identifier using ChangeTrackingState.MostRecentId 7. Query for changed areas using VHD API QueryChangesVirtualDisk. So far I am able to get till step six by passing only VIRTUAL_DISK_ACCESS_GET_INFO flag for OpenVirtualDisk. step 7 gives ACCESS_DENIED.
void openDiskEx()
{
HANDLE vhdHandle = NULL;
VIRTUAL_STORAGE_TYPE storageType = {};
ULONG status = 0L;storageType.DeviceId = VIRTUAL\_STORAGE\_TYPE\_DEVICE\_UNKNOWN; storageType.VendorId = VIRTUAL\_STORAGE\_TYPE\_VENDOR\_UNKNOWN; PCWSTR virtualDiskPath = L"C:\\\\Hyper-V\\\\Virtual Hard Disks\\\\Lacazette\\\\Windows2016.vhdx"; OPEN\_VIRTUAL\_DISK\_PARAMETERS\* pOpenParameter = NULL; status = OpenVirtualDisk(&storageType, virtualDiskPath, VIRTUAL\_DISK\_ACCESS\_ATTACH\_RW | VIRTUAL\_DISK\_ACCESS\_GET\_INFO | VIRTUAL\_DISK\_ACCESS\_DETACH, OPEN\_VIRTUAL\_DISK\_FLAG\_NONE, pOpenParameter, &vhdHandle); std::cout << "opendisk:" << status<< std::endl; if (ERROR\_SUCCESS == status) { DWORD sizeUsed = GET\_VIRTUAL\_DISK\_INFO\_SIZE; WCHAR changeTrackingInfo\[sizeof(GET\_VIRTUAL\_DISK\_INFO) + sizeof(GUID)\]; ::ZeroMemory(changeTrackingInfo, sizeof(changeTrackingInfo)); PGET\_VIRTUAL\_DISK\_INFO virtualDiskInfo = (GET\_VIRTUAL\_DISK\_INFO\*)changeTrackingInfo; virtualDiskInfo->Version = (GET\_VIRTUAL\_DISK\_INFO\_VERSION)GET\_VIRTUAL\_DISK\_INFO\_CHANGE\_TRACKING\_STATE; ULONG virtualDiskInfoSize = sizeof(changeTrackingInfo); status = GetVirtualDiskInformation(vhdHandle, &virtualDiskInfoSize, virtualDiskInfo, &sizeUsed); std::cout << "GetVirtualDiskInformation:" << status << std::endl; if (ERROR\_SUCCESS == status) { ULONG64 virtualDiskSize = virtualDiskInfo->Size.VirtualSize; printf("Disk Infomation:\\n"); GUID virtualDiskGuid = virtualDiskInfo->Identifier; wchar\_t szGUID\[64\] = { 0 }; StringFromGUID2(virtualDiskGuid, szGUID, 64); wprintf(L"ChangeTrackingState.Enabled:%dcazorla19 wrote:
OpenVirtualDisk failed with 32 ERROR_SHARING_VIOLATION.
That obviously means that the virtual disk is locked/mounted and being used by another process. Are you trying to read the change tracking on running Hyper-V virtual machine? I don't think you can do that.
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cazorla19 wrote:
OpenVirtualDisk failed with 32 ERROR_SHARING_VIOLATION.
That obviously means that the virtual disk is locked/mounted and being used by another process. Are you trying to read the change tracking on running Hyper-V virtual machine? I don't think you can do that.
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Yes, I am trying to read the change tracking information when the Virtual machine is online.
Ok, If you can't read the change tracking information from an Administrator account with both SE_BACKUP_NAME and SE_MANAGE_VOLUME_NAME privileges then I don't think it will be possible. Also since the virtual drive is mounted you should change the access mask from VIRTUAL_DISK_ACCESS_ATTACH_RW to VIRTUAL_DISK_ACCESS_ATTACH_RO. I am actually in a Hyper-V environment right now so if I get some time later today I will look into it more. The code sample I gave you is working for me on my offline virtual machines. Best Wishes, -David Delaune
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I am trying out VirtualDisk APIs, So far I am able to Open a VHDX file, get some of the properties by using GetVirtualDiskInformation. But I am not able to get RCT information and ChangedAreas. 1)Opendisk is done with VIRTUAL_DISK_ACCESS_GET_INFO flag. 2)GetVirtualDiskInformation a. Works fine when version flag is set to GET_VIRTUAL_DISK_INFO_SIZE, able to fetch sector size and other information b. Gives ERROR_INSUFFICIENT_BUFFER(122) when version flag is set to GET_VIRTUAL_DISK_INFO_CHANGE_TRACKING_STATE to access diskInfo->ChangeTrackingState.MostRecentId
PGET\_VIRTUAL\_DISK\_INFO diskInfo; ULONG diskInfoSize = sizeof(GET\_VIRTUAL\_DISK\_INFO); std::wcout << "size of diskinfo structure " << diskInfoSize << std::endl; diskInfo = (PGET\_VIRTUAL\_DISK\_INFO)malloc(diskInfoSize); diskInfo->Version = GET\_VIRTUAL\_DISK\_INFO\_SIZE; res = GetVirtualDiskInformation(vhdHandle, &diskInfoSize, diskInfo, NULL); long physicalSize = diskInfo->Size.PhysicalSize; long virtualSize = diskInfo->Size.VirtualSize; long sectorSize = diskInfo->Size.SectorSize; long blockSize = diskInfo->Size.BlockSize; std::wcout << "physicalSize :" << physicalSize << std::endl; std::wcout << "virtualSize :" << virtualSize << std::endl; std::wcout << "sectorSize :" << sectorSize << std::endl; std::wcout << "blockSize :" << blockSize << std::endl; diskInfo->Version = GET\_VIRTUAL\_DISK\_INFO\_CHANGE\_TRACKING\_STATE; res = GetVirtualDiskInformation(vhdHandle, &diskInfoSize, diskInfo, NULL); std::wcout << "\\nrct id:" << diskInfo->ChangeTrackingState.MostRecentId << std::endl;3)queryChangesVirtualDisk gives ACCESS DENIED.
ULONG64 byteOffset = 0L; ULONG64 byteLength = 19327352832; QUERY\_CHANGES\_VIRTUAL\_DISK\_RANGE\* changedAreas = NULL; ULONG rangeCount = 0L; ULONG64 processedLength = 0L; res = QueryChangesVirtualDisk(vhdHandle, "rctX:c2eb01d9:ccb1:405d:acb6:f0e76d055906:00000001", byteOffset, byteLength, QUERY\_CHANGES\_VIRTUAL\_DISK\_FLAG\_NONE, changedAreas, &rangeCount, &processedLength);Can someone please give some ideas on what I am doing wrong?
hi, have you resolve the problem?