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![Pierre Schweitzer](/assets/img/avatar_default.png)
This implies that a sample for W10. It has been backported to NT5.2; not sure how it would work on a W2K3 (feel free to test!)
486 lines
12 KiB
C
486 lines
12 KiB
C
/*++
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Copyright (c) 1989-2000 Microsoft Corporation
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Module Name:
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FspDisp.c
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Abstract:
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This module implements the main dispatch procedure/thread for the Fat
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Fsp
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--*/
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#include "fatprocs.h"
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//
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// Internal support routine, spinlock wrapper.
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//
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PVOID
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FatRemoveOverflowEntry (
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IN PVOLUME_DEVICE_OBJECT VolDo
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);
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//
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// Define our local debug trace level
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//
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#define Dbg (DEBUG_TRACE_FSP_DISPATCHER)
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(PAGE, FatFspDispatch)
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#endif
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VOID
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NTAPI
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FatFspDispatch (
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_In_ PVOID Context
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)
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/*++
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Routine Description:
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This is the main FSP thread routine that is executed to receive
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and dispatch IRP requests. Each FSP thread begins its execution here.
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There is one thread created at system initialization time and subsequent
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threads created as needed.
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Arguments:
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Context - Supplies the thread id.
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Return Value:
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None - This routine never exits
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--*/
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{
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NTSTATUS Status = STATUS_SUCCESS;
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PIRP Irp;
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PIRP_CONTEXT IrpContext;
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PIO_STACK_LOCATION IrpSp;
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BOOLEAN VcbDeleted;
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BOOLEAN ExceptionCompletedIrp = FALSE;
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PVOLUME_DEVICE_OBJECT VolDo;
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UCHAR MajorFunction = 0;
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PAGED_CODE();
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IrpContext = (PIRP_CONTEXT)Context;
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Irp = IrpContext->OriginatingIrp;
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IrpSp = IoGetCurrentIrpStackLocation( Irp );
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//
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// Now because we are the Fsp we will force the IrpContext to
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// indicate true on Wait.
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//
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SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT | IRP_CONTEXT_FLAG_IN_FSP);
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//
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// If this request has an associated volume device object, remember it.
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//
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if ( IrpSp->FileObject != NULL ) {
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VolDo = CONTAINING_RECORD( IrpSp->DeviceObject,
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VOLUME_DEVICE_OBJECT,
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DeviceObject );
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} else {
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VolDo = NULL;
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}
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//
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// Now case on the function code. For each major function code,
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// either call the appropriate FSP routine or case on the minor
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// function and then call the FSP routine. The FSP routine that
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// we call is responsible for completing the IRP, and not us.
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// That way the routine can complete the IRP and then continue
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// post processing as required. For example, a read can be
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// satisfied right away and then read can be done.
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//
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// We'll do all of the work within an exception handler that
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// will be invoked if ever some underlying operation gets into
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// trouble (e.g., if FatReadSectorsSync has trouble).
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//
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while ( TRUE ) {
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ExceptionCompletedIrp = FALSE;
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DebugTrace(0, Dbg, "FatFspDispatch: Irp = %p\n", Irp);
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//
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// If this Irp was top level, note it in our thread local storage.
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//
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FsRtlEnterFileSystem();
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if ( FlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_RECURSIVE_CALL) ) {
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IoSetTopLevelIrp( (PIRP)FSRTL_FSP_TOP_LEVEL_IRP );
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} else {
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IoSetTopLevelIrp( Irp );
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}
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MajorFunction = IrpContext->MajorFunction;
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_SEH2_TRY {
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switch ( MajorFunction ) {
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//
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// For Create Operation,
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//
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case IRP_MJ_CREATE:
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Status = FatCommonCreate( IrpContext, Irp );
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break;
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//
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// For close operations. We do a little kludge here in case
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// this close causes a volume to go away. It will NULL the
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// VolDo local variable so that we will not try to look at
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// the overflow queue.
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//
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case IRP_MJ_CLOSE:
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{
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PVCB Vcb;
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PFCB Fcb;
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PCCB Ccb;
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TYPE_OF_OPEN TypeOfOpen;
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//
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// Extract and decode the file object
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//
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TypeOfOpen = FatDecodeFileObject( IrpSp->FileObject, &Vcb, &Fcb, &Ccb );
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//
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// Do the close. We have a slightly different format
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// for this call because of the async closes.
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//
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Status = FatCommonClose( Vcb,
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Fcb,
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Ccb,
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TypeOfOpen,
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TRUE,
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TRUE,
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&VcbDeleted );
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//
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// If the VCB was deleted, do not try to access it later.
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//
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if (VcbDeleted) {
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VolDo = NULL;
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}
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NT_ASSERT(Status == STATUS_SUCCESS);
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FatCompleteRequest( IrpContext, Irp, Status );
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break;
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}
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//
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// For read operations
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//
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case IRP_MJ_READ:
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(VOID) FatCommonRead( IrpContext, Irp );
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break;
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//
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// For write operations,
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//
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case IRP_MJ_WRITE:
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(VOID) FatCommonWrite( IrpContext, Irp );
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break;
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//
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// For Query Information operations,
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//
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case IRP_MJ_QUERY_INFORMATION:
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(VOID) FatCommonQueryInformation( IrpContext, Irp );
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break;
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//
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// For Set Information operations,
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//
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case IRP_MJ_SET_INFORMATION:
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(VOID) FatCommonSetInformation( IrpContext, Irp );
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break;
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//
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// For Query EA operations,
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//
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case IRP_MJ_QUERY_EA:
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(VOID) FatCommonQueryEa( IrpContext, Irp );
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break;
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//
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// For Set EA operations,
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//
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case IRP_MJ_SET_EA:
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(VOID) FatCommonSetEa( IrpContext, Irp );
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break;
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//
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// For Flush buffers operations,
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//
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case IRP_MJ_FLUSH_BUFFERS:
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(VOID) FatCommonFlushBuffers( IrpContext, Irp );
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break;
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//
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// For Query Volume Information operations,
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//
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case IRP_MJ_QUERY_VOLUME_INFORMATION:
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(VOID) FatCommonQueryVolumeInfo( IrpContext, Irp );
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break;
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//
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// For Set Volume Information operations,
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//
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case IRP_MJ_SET_VOLUME_INFORMATION:
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(VOID) FatCommonSetVolumeInfo( IrpContext, Irp );
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break;
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//
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// For File Cleanup operations,
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//
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case IRP_MJ_CLEANUP:
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(VOID) FatCommonCleanup( IrpContext, Irp );
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break;
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//
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// For Directory Control operations,
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//
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case IRP_MJ_DIRECTORY_CONTROL:
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(VOID) FatCommonDirectoryControl( IrpContext, Irp );
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break;
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//
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// For File System Control operations,
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//
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case IRP_MJ_FILE_SYSTEM_CONTROL:
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(VOID) FatCommonFileSystemControl( IrpContext, Irp );
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break;
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//
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// For Lock Control operations,
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//
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case IRP_MJ_LOCK_CONTROL:
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(VOID) FatCommonLockControl( IrpContext, Irp );
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break;
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//
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// For Device Control operations,
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//
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case IRP_MJ_DEVICE_CONTROL:
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(VOID) FatCommonDeviceControl( IrpContext, Irp );
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break;
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//
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// For the Shutdown operation,
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//
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case IRP_MJ_SHUTDOWN:
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(VOID) FatCommonShutdown( IrpContext, Irp );
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break;
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//
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// For plug and play operations.
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//
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case IRP_MJ_PNP:
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//
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// I don't believe this should ever occur, but allow for the unexpected.
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//
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(VOID) FatCommonPnp( IrpContext, Irp );
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break;
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//
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// For any other major operations, return an invalid
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// request.
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//
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default:
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FatCompleteRequest( IrpContext, Irp, STATUS_INVALID_DEVICE_REQUEST );
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break;
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}
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} _SEH2_EXCEPT(FatExceptionFilter( IrpContext, _SEH2_GetExceptionInformation() )) {
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//
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// We had some trouble trying to perform the requested
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// operation, so we'll abort the I/O request with
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// the error status that we get back from the
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// execption code.
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//
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(VOID) FatProcessException( IrpContext, Irp, _SEH2_GetExceptionCode() );
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ExceptionCompletedIrp = TRUE;
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} _SEH2_END;
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IoSetTopLevelIrp( NULL );
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FsRtlExitFileSystem();
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if (MajorFunction == IRP_MJ_CREATE && !ExceptionCompletedIrp && Status != STATUS_PENDING) {
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//
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// Creates are completed here. IrpContext is also freed here.
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//
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FatCompleteRequest( IrpContext, Irp, Status );
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}
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//
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// If there are any entries on this volume's overflow queue, service
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// them.
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//
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if ( VolDo != NULL ) {
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PVOID Entry;
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//
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// We have a volume device object so see if there is any work
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// left to do in its overflow queue.
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//
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Entry = FatRemoveOverflowEntry( VolDo );
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//
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// There wasn't an entry, break out of the loop and return to
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// the Ex Worker thread.
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//
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if ( Entry == NULL ) {
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break;
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}
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//
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// Extract the IrpContext, Irp, and IrpSp, and loop.
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//
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IrpContext = CONTAINING_RECORD( Entry,
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IRP_CONTEXT,
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WorkQueueItem.List );
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SetFlag(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT | IRP_CONTEXT_FLAG_IN_FSP);
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Irp = IrpContext->OriginatingIrp;
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IrpSp = IoGetCurrentIrpStackLocation( Irp );
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continue;
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} else {
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break;
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}
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}
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return;
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}
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//
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// Internal support routine, spinlock wrapper.
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//
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PVOID
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FatRemoveOverflowEntry (
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IN PVOLUME_DEVICE_OBJECT VolDo
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)
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{
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PVOID Entry;
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KIRQL SavedIrql;
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KeAcquireSpinLock( &VolDo->OverflowQueueSpinLock, &SavedIrql );
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if (VolDo->OverflowQueueCount > 0) {
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//
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// There is overflow work to do in this volume so we'll
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// decrement the Overflow count, dequeue the IRP, and release
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// the Event
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//
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VolDo->OverflowQueueCount -= 1;
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Entry = RemoveHeadList( &VolDo->OverflowQueue );
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} else {
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VolDo->PostedRequestCount -= 1;
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Entry = NULL;
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}
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KeReleaseSpinLock( &VolDo->OverflowQueueSpinLock, SavedIrql );
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return Entry;
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}
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