PMRX_EXTENDFILE_CALLDOWN callback function (mrx.h)

Article
10/12/2023

The MRxExtendForCache routine is called by RDBSS to request that a network mini-redirector extend a file when the file is being cached by the cache manager.

Syntax

PMRX_EXTENDFILE_CALLDOWN PmrxExtendfileCalldown;

ULONG PmrxExtendfileCalldown(
  IN OUT PRX_CONTEXT RxContext,
  IN OUT PLARGE_INTEGER NewFileSize,
  OUT PLARGE_INTEGER NewAllocationSize
)
{...}

Parameters

RxContext

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

NewFileSize

[in, out] A pointer to the LARGE_INTEGER structure indicating the byte count of the new file size.

NewAllocationSize

[out] A pointer to the LARGE_INTEGER structure for storing the new allocation size when MRxExtendForCache returns.

Return value

MRxExtendForCache returns STATUS_SUCCESS on success or an error code on failure.

Remarks

MRxExtendForCache handles network requests to extend the file for cached I/O.

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

LowIoContext.Operation is set to LOWIO_OP_WRITE
LowIoContext.ParamsFor.ReadWrite.Flags has the LOWIO_READWRITEFLAG_EXTENDING_FILESIZE bit set

A network mini-redirector that caches file or directory information may need to invalidate its cache information when the file is extended.

Requirements

Requirement	Value
Target Platform	Desktop
Header	mrx.h (include Mrx.h)