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/************************************************************************* 
* 
* File: close.c 
* 
* Module: Sample File System Driver (Kernel mode execution only) 
* 
* Description: 
*	Should contain code to handle the "Close" dispatch entry point. 
*	This file serves as a placeholder. Please update this file as part 
*	of designing and implementing your FSD. 
* 
* Author: R. Nagar 
* 
* (c) 1996-97 Rajeev Nagar, All Rights Reserved 
* 
*************************************************************************/ 
 
#include			"sfsd.h" 
 
// define the file specific bug-check id 
#define			SFSD_BUG_CHECK_ID				SFSD_FILE_CLOSE 
 
 
 
/************************************************************************* 
* 
* Function: SFsdClose() 
* 
* Description: 
*	The I/O Manager will invoke this routine to handle a close 
*	request 
* 
* Expected Interrupt Level (for execution) : 
* 
*  IRQL_PASSIVE_LEVEL (invocation at higher IRQL will cause execution 
*	to be deferred to a worker thread context) 
* 
* Return Value: Does not matter! 
* 
*************************************************************************/ 
NTSTATUS SFsdClose( 
PDEVICE_OBJECT		DeviceObject,		// the logical volume device object 
PIRP					Irp)					// I/O Request Packet 
{ 
	NTSTATUS				RC = STATUS_SUCCESS; 
   PtrSFsdIrpContext	PtrIrpContext = NULL; 
	BOOLEAN				AreWeTopLevel = FALSE; 
 
	FsRtlEnterFileSystem(); 
	ASSERT(DeviceObject); 
	ASSERT(Irp); 
 
	// set the top level context 
	AreWeTopLevel = SFsdIsIrpTopLevel(Irp); 
 
	try { 
 
		// get an IRP context structure and issue the request 
		PtrIrpContext = SFsdAllocateIrpContext(Irp, DeviceObject); 
		ASSERT(PtrIrpContext); 
 
		RC = SFsdCommonClose(PtrIrpContext, Irp); 
 
	} except (SFsdExceptionFilter(PtrIrpContext, GetExceptionInformation())) { 
 
		RC = SFsdExceptionHandler(PtrIrpContext, Irp); 
 
		SFsdLogEvent(SFSD_ERROR_INTERNAL_ERROR, RC); 
	} 
 
	if (AreWeTopLevel) { 
		IoSetTopLevelIrp(NULL); 
	} 
 
	FsRtlExitFileSystem(); 
 
	return(RC); 
} 
 
 
 
 
/************************************************************************* 
* 
* Function: SFsdCommonClose() 
* 
* Description: 
*	The actual work is performed here. This routine may be invoked in one' 
*	of the two possible contexts: 
*	(a) in the context of a system worker thread 
*	(b) in the context of the original caller 
* 
* Expected Interrupt Level (for execution) : 
* 
*  IRQL_PASSIVE_LEVEL 
* 
* Return Value: Does not matter! 
* 
*************************************************************************/ 
NTSTATUS	SFsdCommonClose( 
PtrSFsdIrpContext			PtrIrpContext, 
PIRP							PtrIrp) 
{ 
	NTSTATUS					RC = STATUS_SUCCESS; 
	PIO_STACK_LOCATION	PtrIoStackLocation = NULL; 
	PFILE_OBJECT			PtrFileObject = NULL; 
	PtrSFsdFCB				PtrFCB = NULL; 
	PtrSFsdCCB				PtrCCB = NULL; 
	PtrSFsdVCB				PtrVCB = NULL; 
	PtrSFsdNTRequiredFCB	PtrReqdFCB = NULL; 
	PERESOURCE				PtrResourceAcquired = NULL; 
	IO_STATUS_BLOCK		LocalIoStatus; 
 
	BOOLEAN					CompleteIrp = TRUE; 
	BOOLEAN					PostRequest = FALSE; 
 
	BOOLEAN					CanWait = FALSE; 
 
	try { 
		// First, get a pointer to the current I/O stack location 
		PtrIoStackLocation = IoGetCurrentIrpStackLocation(PtrIrp); 
		ASSERT(PtrIoStackLocation); 
 
		PtrFileObject = PtrIoStackLocation->FileObject; 
		ASSERT(PtrFileObject); 
 
		// Get the FCB and CCB pointers 
		PtrCCB = (PtrSFsdCCB)(PtrFileObject->FsContext2); 
		ASSERT(PtrCCB); 
		PtrFCB = PtrCCB->PtrFCB; 
		ASSERT(PtrFCB); 
 
		PtrVCB =	(PtrSFsdVCB)(PtrIrpContext->TargetDeviceObject->DeviceExtension); 
		ASSERT(PtrVCB); 
		ASSERT(PtrVCB->NodeIdentifier.NodeType == SFSD_NODE_TYPE_VCB); 
 
		// Steps you will probably take at this point are: 
		// (a) Acquire the VCB exclusively 
		// (b) Acquire the file (FCB) exclusively 
		// (c) Delete the CCB structure (free memory) 
		// (d) If this is the last close, release the FCB structure (unless you keep these 
		//		 around for "delayed close" functionality. 
		// Note that it is often the case that the close dispatch entry point is invoked 
		// in the most inconvenient of situations (when it is not possible, for example, 
		// to safely acquire certain required resources without deadlocking or waiting). 
		// Therefore, be extremely careful in implementing this close dispatch entry point. 
		// Also note that you do not have the option of returning a failure code from the 
		// close dispatch entry point; the system expects that the close will always succeed. 
 
		try_exit:	NOTHING; 
 
	} finally { 
 
		// See the read/write examples for how to fill in this portion 
 
	} // end of "finally" processing 
 
	return(RC); 
}