IVdsVolume::Extend method (vds.h)

Article
02/09/2023

[Beginning with Windows 8 and Windows Server 2012, the Virtual Disk Service COM interface is superseded by the Windows Storage Management API.]

Expands the size of the current volume by adding disk extents to each member of each plex.

Syntax

HRESULT Extend(
  [in]  VDS_INPUT_DISK *pInputDiskArray,
  [in]  LONG           lNumberOfDisks,
  [out] IVdsAsync      **ppAsync
);

Parameters

[in] pInputDiskArray

Pointer to an array of VDS_INPUT_DISK structures; one structure for each disk.

Note Callers should not use a default member index in conjunction with the Extend method, unless the volume has only one plex with only one member.

[in] lNumberOfDisks

The total number of disks in the volume. Callers can pass zero when the volume plexes contain enough space to extend the volume; pInputDiskArray must be NULL.

[out] ppAsync

The address of an IVdsAsync interface pointer, which VDS initializes on return. Callers must release the interface. Use this pointer to cancel, wait for, or query the status of the operation. If you call the IVdsAsync::Wait method on this interface and a success HRESULT value is returned, you must release the interfaces returned in the VDS_ASYNC_OUTPUT structure by calling the IUnknown::Release method on each interface pointer. However, if Wait returns a failure HRESULT value, or if the pHrResult parameter of Wait receives a failure HRESULT value, the interface pointers in the VDS_ASYNC_OUTPUT structure are NULL and do not need to be released. You can test for success or failure HRESULT values by using the SUCCEEDED and FAILED macros defined in Winerror.h.

Return value

This method can return standard HRESULT values, such as E_INVALIDARG or E_OUTOFMEMORY, and VDS-specific return values. It can also return converted system error codes using the HRESULT_FROM_WIN32 macro. Errors can originate from VDS itself or from the underlying VDS provider that is being used. Possible return values include the following.

Return code/value	Description
S_OK	The method competed successfully.
VDS_E_CANNOT_EXTEND 0x8004240EL	The volume cannot be extended because the file system on the volume does not support the operation.
VDS_E_NOT_ENOUGH_SPACE 0x8004240FL	There is not enough space to extend the volume.
VDS_E_VOLUME_NOT_HEALTHY 0x8004243EL	The volume is not healthy.

Remarks

This method extends a simple volume on the same disk, or creates a spanned volume by extending the volume to multiple disks. Callers can extend a volume on a basic disk, however the disk extent must be contiguous with the volume.

VDS automatically extends the file system to fit the extended volume size. The file system must support this operation. VDS extends the file system, but not the volume, if a caller fails to specify the extents to be used.

Extend and shrink operations are supported only on NTFS and RAW volumes.

VDS applies the following rules when extending a volume:

For simple and spanned plex types, VDS extends the sole member of the plex with any disk extent not already contributing to another plex—whether the extent is on the same disk or not. VDS uses disk extents in the order given by the caller, ignoring the member index of the extent. Unless on a basic disk, VDS can extend the sole member of a plex with any disk extent on the same disk or on a different disk.
For striped and striped with parity plex types, VDS assigns an extent to the member of the plex as follows:
- The extent goes to the member index specified by the caller.
- The extent goes to the member index that occupies the same disk when the caller fails to specify a member ID.
VDS never assigns an extent to multiple members on the same disk. The caller must specify a member for all extents or none; the caller cannot specify a member for some extents and not for others.

When the caller passes NULL for pInputDiskArray and zero for lNumberOfDisks, VDS returns S_FALSE in the async object and S_OK for the method. In this case, S_OK indicates that VDS has started the operation, but the operation is synchronous.

Implementers must return a pointer to the IVdsAsync interface for this method, regardless of whether the call initiates an asynchronous operation.

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	vds.h
Library	Uuid.lib