IVdsLunMpio::GetPathInfo method

[Beginning with Windows 8 and Windows Server 2012, the Virtual Disk Service COM interface is superseded by the Windows Storage Management API.]

Returns an array of VDS_PATH_INFO structures, one for each path to the LUN.

Syntax


HRESULT GetPathInfo(
  [out] VDS_PATH_INFO **ppPaths,
  [out] LONG          *plNumberOfPaths
);

Parameters

ppPaths [out]

The address of a variable that receives an array of VDS_PATH_INFO structures. Callers must free each element in the array, and the array itself, by using the CoTaskMemFree function.

plNumberOfPaths [out]

The address of a variable that receives the number of elements in the array returned in the ppPaths parameter.

The number of paths returned by this method will match the number of paths returned by the IVdsLunMpio::GetLoadBalancePolicy method.

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/valueDescription
S_OK

The path information was successfully returned.

VDS_E_PROVIDER_CACHE_CORRUPT
0x8004241FL

The cache of the provider is corrupted. This indicates a software or communication problem inside a provider that caches information about the attached devices. The caller can use the IVdsHwProvider::Reenumerate method followed by the IVdsHwProvider::Refresh method to restore the cache.

VDS_E_OBJECT_DELETED
0x8004240BL

The LUN object is no longer present.

VDS_E_OBJECT_STATUS_FAILED
0x80042431L

The LUN is in a failed state and is unable to perform the requested operation.

VDS_E_ANOTHER_CALL_IN_PROGRESS
0x80042404L

Another operation is in progress. This operation cannot proceed until previous operations are complete.

 

Notes to Implementers

To match a LUN path with an HBA port WWN:

  1. From your DSM, retrieve the PDOSCSI_ADDR structure that is associated with your LUN path. Note the value of the PortNumber member.
  2. Using the HBA API, enumerate the adapters.
  3. For each adapter, enumerate its ports.
  4. For each port, get the attributes.
    • The attributes structure should have an OSDeviceName member, which is a string of the form \\.\ScsiX:, where the value of X corresponds to the SCSI port number. Note that the case of the string is insensitive. Also note that the value of X can be more than one digit.
    • If the value of X matches the PortNumber from step 1, then you have found the corresponding port. Retrieve the WWN from the PortWWN member of the attributes structure.

For more information about these structures, see the T11 committee's Fibre Channel HBA API specification.

You need to return information only for paths on the computer where your hardware provider is installed.

Remarks

Hardware providers do not need to return the VDS_OBJECT_ID at hbaPortProp.id of VDS_PATH_INFO and should just set this to GUID_NULL. This ID will be filled in by the system when this call is passed back to applications. If the service cannot find the corresponding HBA port, GUID_NULL will be used. The application will interpret this to mean that the HBA port is unknown to VDS.

Requirements

Minimum supported client

Windows Vista [desktop apps only]

Minimum supported server

Windows Server 2003 R2 [desktop apps only]

Redistributable

VDS 1.1

Header

Vds.h

Library

Uuid.lib

See also

VDS_PATH_INFO
IVdsLunMpio

 

 

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