NTSTATUS
CdFsdDispatch (
_In_ PDEVICE_OBJECT DeviceObject,
_Inout_ PIRP Irp
)
/*++
Routine Description:
This is the driver entry to all of the Fsd dispatch points.
Conceptually the Io routine will call this routine on all requests
to the file system. We case on the type of request and invoke the
correct handler for this type of request. There is an exception filter
to catch any exceptions in the CDFS code as well as the CDFS process
exception routine.
This routine allocates and initializes the IrpContext for this request as
well as updating the top-level thread context as necessary. We may loop
in this routine if we need to retry the request for any reason. The
status code STATUS_CANT_WAIT is used to indicate this. Suppose the disk
in the drive has changed. An Fsd request will proceed normally until it
recognizes this condition. STATUS_VERIFY_REQUIRED is raised at that point
and the exception code will handle the verify and either return
STATUS_CANT_WAIT or STATUS_PENDING depending on whether the request was
posted.
Arguments:
DeviceObject - Supplies the volume device object for this request
Irp - Supplies the Irp being processed
Return Value:
NTSTATUS - The FSD status for the IRP
--*/
{
THREAD_CONTEXT ThreadContext = {0};
PIRP_CONTEXT IrpContext = NULL;
BOOLEAN Wait;
#ifdef CD_SANITY
PVOID PreviousTopLevel;
#endif
NTSTATUS Status;
#if DBG
KIRQL SaveIrql = KeGetCurrentIrql();
#endif
ASSERT_OPTIONAL_IRP( Irp );
UNREFERENCED_PARAMETER( DeviceObject );
FsRtlEnterFileSystem();
#ifdef CD_SANITY
PreviousTopLevel = IoGetTopLevelIrp();
#endif
//
// Loop until this request has been completed or posted.
//
do {
//
// Use a try-except to handle the exception cases.
//
try {
//
// If the IrpContext is NULL then this is the first pass through
// this loop.
//
if (IrpContext == NULL) {
//
// Decide if this request is waitable an allocate the IrpContext.
// If the file object in the stack location is NULL then this
// is a mount which is always waitable. Otherwise we look at
// the file object flags.
//
if (IoGetCurrentIrpStackLocation( Irp )->FileObject == NULL) {
Wait = TRUE;
} else {
Wait = CanFsdWait( Irp );
}
IrpContext = CdCreateIrpContext( Irp, Wait );
//
// Update the thread context information.
//
CdSetThreadContext( IrpContext, &ThreadContext );
#ifdef CD_SANITY
NT_ASSERT( !CdTestTopLevel ||
SafeNodeType( IrpContext->TopLevel ) == CDFS_NTC_IRP_CONTEXT );
#endif
//
// Otherwise cleanup the IrpContext for the retry.
//
} else {
//
// Set the MORE_PROCESSING flag to make sure the IrpContext
// isn't inadvertently deleted here. Then cleanup the
// IrpContext to perform the retry.
//
SetFlag( IrpContext->Flags, IRP_CONTEXT_FLAG_MORE_PROCESSING );
CdCleanupIrpContext( IrpContext, FALSE );
}
//
// Case on the major irp code.
//
switch (IrpContext->MajorFunction) {
case IRP_MJ_CREATE :
Status = CdCommonCreate( IrpContext, Irp );
break;
case IRP_MJ_CLOSE :
Status = CdCommonClose( IrpContext, Irp );
break;
case IRP_MJ_READ :
//
// If this is an Mdl complete request, don't go through
// common read.
//
if (FlagOn( IrpContext->MinorFunction, IRP_MN_COMPLETE )) {
Status = CdCompleteMdl( IrpContext, Irp );
} else {
Status = CdCommonRead( IrpContext, Irp );
}
break;
case IRP_MJ_WRITE :
Status = CdCommonWrite( IrpContext, Irp );
break;
case IRP_MJ_QUERY_INFORMATION :
Status = CdCommonQueryInfo( IrpContext, Irp );
break;
case IRP_MJ_SET_INFORMATION :
Status = CdCommonSetInfo( IrpContext, Irp );
break;
case IRP_MJ_QUERY_VOLUME_INFORMATION :
Status = CdCommonQueryVolInfo( IrpContext, Irp );
break;
case IRP_MJ_DIRECTORY_CONTROL :
Status = CdCommonDirControl( IrpContext, Irp );
break;
case IRP_MJ_FILE_SYSTEM_CONTROL :
Status = CdCommonFsControl( IrpContext, Irp );
break;
case IRP_MJ_DEVICE_CONTROL :
Status = CdCommonDevControl( IrpContext, Irp );
break;
case IRP_MJ_LOCK_CONTROL :
Status = CdCommonLockControl( IrpContext, Irp );
break;
case IRP_MJ_CLEANUP :
Status = CdCommonCleanup( IrpContext, Irp );
break;
case IRP_MJ_PNP :
Status = CdCommonPnp( IrpContext, Irp );
break;
case IRP_MJ_SHUTDOWN :
Status = CdCommonShutdown( IrpContext, Irp );
break;
default :
Status = STATUS_INVALID_DEVICE_REQUEST;
CdCompleteRequest( IrpContext, Irp, Status );
}
} except( CdExceptionFilter( IrpContext, GetExceptionInformation() )) {
Status = CdProcessException( IrpContext, Irp, GetExceptionCode() );
}
} while (Status == STATUS_CANT_WAIT);
#ifdef CD_SANITY
NT_ASSERT( !CdTestTopLevel ||
(PreviousTopLevel == IoGetTopLevelIrp()) );
#endif
FsRtlExitFileSystem();
NT_ASSERT( SaveIrql == KeGetCurrentIrql( ));
return Status;
}
VOID
CdFspDispatch (
IN PIRP_CONTEXT IrpContext
)
/*++
Routine Description:
This is the main FSP thread routine that is executed to receive
and dispatch IRP requests. Each FSP thread begins its execution here.
There is one thread created at system initialization time and subsequent
threads created as needed.
Arguments:
IrpContext - IrpContext for a request to process.
Return Value:
None
--*/
{
THREAD_CONTEXT ThreadContext;
NTSTATUS Status;
PIRP Irp = IrpContext->Irp;
PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation( Irp );
PVOLUME_DEVICE_OBJECT VolDo = NULL;
//
// If this request has an associated volume device object, remember it.
//
if (IrpSp->FileObject != NULL) {
VolDo = CONTAINING_RECORD( IrpSp->DeviceObject,
VOLUME_DEVICE_OBJECT,
DeviceObject );
}
//
// Now case on the function code. For each major function code,
// either call the appropriate worker routine. This routine that
// we call is responsible for completing the IRP, and not us.
// That way the routine can complete the IRP and then continue
// post processing as required. For example, a read can be
// satisfied right away and then read can be done.
//
// We'll do all of the work within an exception handler that
// will be invoked if ever some underlying operation gets into
// trouble.
//
while ( TRUE ) {
//
// Set all the flags indicating we are in the Fsp.
//
SetFlag( IrpContext->Flags, IRP_CONTEXT_FSP_FLAGS );
FsRtlEnterFileSystem();
CdSetThreadContext( IrpContext, &ThreadContext );
while (TRUE) {
try {
//
// Reinitialize for the next try at completing this
// request.
//
Status =
IrpContext->ExceptionStatus = STATUS_SUCCESS;
//
// Initialize the Io status field in the Irp.
//
Irp->IoStatus.Status = STATUS_SUCCESS;
Irp->IoStatus.Information = 0;
//
// Case on the major irp code.
//
switch (IrpContext->MajorFunction) {
case IRP_MJ_CREATE :
CdCommonCreate( IrpContext, Irp );
break;
case IRP_MJ_CLOSE :
ASSERT( FALSE );
break;
case IRP_MJ_READ :
CdCommonRead( IrpContext, Irp );
break;
case IRP_MJ_QUERY_INFORMATION :
CdCommonQueryInfo( IrpContext, Irp );
break;
case IRP_MJ_SET_INFORMATION :
CdCommonQueryInfo( IrpContext, Irp );
break;
case IRP_MJ_QUERY_VOLUME_INFORMATION :
CdCommonQueryVolInfo( IrpContext, Irp );
break;
case IRP_MJ_DIRECTORY_CONTROL :
CdCommonDirControl( IrpContext, Irp );
break;
case IRP_MJ_FILE_SYSTEM_CONTROL :
CdCommonFsControl( IrpContext, Irp );
break;
case IRP_MJ_DEVICE_CONTROL :
CdCommonDevControl( IrpContext, Irp );
break;
case IRP_MJ_LOCK_CONTROL :
CdCommonLockControl( IrpContext, Irp );
break;
case IRP_MJ_CLEANUP :
CdCommonCleanup( IrpContext, Irp );
break;
default :
Status = STATUS_INVALID_DEVICE_REQUEST;
CdCompleteRequest( IrpContext, Irp, Status );
}
} except( CdExceptionFilter( IrpContext, GetExceptionInformation() )) {
Status = CdProcessException( IrpContext, Irp, GetExceptionCode() );
}
//
// Break out of the loop if we didn't get CANT_WAIT.
//
if (Status != STATUS_CANT_WAIT) { break; }
//
// We are retrying this request. Cleanup the IrpContext for the retry.
//
SetFlag( IrpContext->Flags, IRP_CONTEXT_FLAG_MORE_PROCESSING );
CdCleanupIrpContext( IrpContext, FALSE );
}
FsRtlExitFileSystem();
//
// If there are any entries on this volume's overflow queue, service
// them.
//
if (VolDo != NULL) {
KIRQL SavedIrql;
PVOID Entry = NULL;
//
// We have a volume device object so see if there is any work
// left to do in its overflow queue.
//
KeAcquireSpinLock( &VolDo->OverflowQueueSpinLock, &SavedIrql );
if (VolDo->OverflowQueueCount > 0) {
//
// There is overflow work to do in this volume so we'll
// decrement the Overflow count, dequeue the IRP, and release
// the Event
//
VolDo->OverflowQueueCount -= 1;
Entry = RemoveHeadList( &VolDo->OverflowQueue );
}
KeReleaseSpinLock( &VolDo->OverflowQueueSpinLock, SavedIrql );
//
// There wasn't an entry, break out of the loop and return to
// the Ex Worker thread.
//
if (Entry == NULL) { break; }
//
// Extract the IrpContext , Irp, set wait to TRUE, and loop.
//
IrpContext = CONTAINING_RECORD( Entry,
IRP_CONTEXT,
WorkQueueItem.List );
Irp = IrpContext->Irp;
IrpSp = IoGetCurrentIrpStackLocation( Irp );
continue;
}
break;
}
//
// Decrement the PostedRequestCount if there was a volume device object.
//
if (VolDo) {
InterlockedDecrement( &VolDo->PostedRequestCount );
}
return;
}