MRxCreate routine

Article
03/14/2023

TheMRxCreate routine is called by RDBSS to request that the network mini-redirector create a file system object.

Syntax

PMRX_CALLDOWN MRxCreate;

NTSTATUS MRxCreate(
  _Inout_ PRX_CONTEXT RxContext
)
{ ... }

Parameters

RxContext [in, out]
A pointer to the RX_CONTEXT structure. This parameter contains the IRP that is requesting the operation.

Return value

MRxCreate returns STATUS_SUCCESS on success or an appropriate NTSTATUS value, such as one of the following:

Return code	Description
STATUS_INSUFFICIENT_RESOURCES	There were insufficient resources to complete the operation.
STATUS_NETWORK_ACCESS_DENIED	Network access was denied. This error can be returned if the network mini-redirector was asked to open a new file on a read-only share.
STATUS_NOT_IMPLEMENTED	A feature that is requested, such as remote boot or a remote page file, is not implemented.
STATUS_NOT_SUPPORTED	A feature that is requested, such as extended attributes, is not supported.
STATUS_OBJECT_NAME_COLLISION	The network mini-redirector was asked to create a file that already exists.
STATUS_OBJECT_NAME_NOT_FOUND	The object name was not found. This error can be returned if the network mini-redirector was asked to open a file that doesn't exist.
STATUS_OBJECT_PATH_NOT_FOUND	The object path was not found. This error can be returned if an NTFS stream object was requested and the remote file system does not support streams.
STATUS_REPARSE	A reparse is required to handle a symbolic link.
STATUS_RETRY	The operation should be retried. This error can be returned if the network mini-redirector encountered a sharing violation or an access denied error.

Remarks

MRxCreate is called by RDBSS to request that the network mini-redirector open a file system object across the network. This call is issued by RDBSS in response to receiving an IRP_MJ_CREATE request.

Before calling MRxCreate, RDBSS modifies the following members in the RX_CONTEXT structure pointed to by the RxContext parameter:

pRelevantSrvOpen is set to the SRV_OPEN structure.

Create.pSrvCall is set to the SRV_CALL structure.

Create.NtCreateParameters is set to the requested NT_CREATE_PARAMETERS.

In the context of a network mini-redirector, a file object refers to the associated file control block (FCB) and file object extension (FOBX) structures. There is a one to one correspondence between file objects and FOBXs. Many file objects will refer to the same FCB, which represents a single file on a remote server. A client can have several different open requests (NtCreateFile requests) on the same FCB and each of these will create a new file object. RDBSS and network mini-redirectors can choose to send fewer MRxCreate requests than the NtCreateFile requests received, in effect sharing an SRV_OPEN structure among several FOBXs.

If the MRxCreate request was for a file overwrite and MRxCreate returned STATUS_SUCCESS, then RDBSS will acquire the paging I/O resource and truncate the file. If the file is being cached by cache manager, RDBSS will update the sizes the cache manager has with the ones just received from the server.

Before returning, MRxCreate must set the CurrentIrp->IoStatus.Information member of the RX_CONTEXT structure pointed to by the RxContext parameter.

Requirements

Target platform	Desktop
Header	Mrx.h (include Mrx.h)