close.c

windows 2000中的UDF文件系统的驱动程序.只有读的功能,不支持未关闭的盘片.只支持UDF2.0以下版本,不支持VAT格式的UDF.

/*++

Copyright (c) 1989  Microsoft Corporation

Module Name:

    Close.c

Abstract:

    This module implements the File Close routine for Udfs called by the
    Fsd/Fsp dispatch routines.

    The close operation interacts with both the async and delayed close queues
    in the UdfData structure.  Since close may be called recursively we may
    violate the locking order in acquiring the Vcb or Fcb.  In this case
    we may move the request to the async close queue.  If this is the last
    reference on the Fcb and there is a chance the user may reopen this
    file again soon we would like to defer the close.  In this case we
    may move the request to the delayed close queue.

    Once we are past the decode file operation there is no need for the
    file object.  If we are moving the request to either of the work
    queues then we remember all of the information from the file object and
    complete the request with STATUS_SUCCESS.  The Io system can then
    reuse the file object and we can complete the request when convenient.

    The async close queue consists of requests which we would like to
    complete as soon as possible.  They are queued using the original
    IrpContext where some of the fields have been overwritten with
    information from the file object.  We will extract this information,
    cleanup the IrpContext and then call the close worker routine.

    The delayed close queue consists of requests which we would like to
    defer the close for.  We keep size of this list within a range
    determined by the size of the system.  We let it grow to some maximum
    value and then shrink to some minimum value.  We allocate a small
    structure which contains the key information from the file object
    and use this information along with an IrpContext on the stack
    to complete the request.

Author:

    Dan Lovinger    [DanLo]     04-Nov-1996

Revision History:

--*/

#include "UdfProcs.h"

//
//  The Bug check file id for this module
//

#define BugCheckFileId                   (UDFS_BUG_CHECK_CLOSE)

//
//  The local debug trace level
//

#define Dbg                              (UDFS_DEBUG_LEVEL_CLOSE)

//
//  Local support routines
//

BOOLEAN
UdfCommonClosePrivate (
    IN PIRP_CONTEXT IrpContext,
    IN PVCB Vcb,
    IN PFCB Fcb,
    IN ULONG UserReference,
    IN BOOLEAN FromFsd
    );

VOID
UdfQueueClose (
    IN PIRP_CONTEXT IrpContext,
    IN PFCB Fcb,
    IN ULONG UserReference,
    IN BOOLEAN DelayedClose
    );

PIRP_CONTEXT
UdfRemoveClose (
    IN PVCB Vcb OPTIONAL
    );

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, UdfCommonClose)
#pragma alloc_text(PAGE, UdfCommonClosePrivate)
#pragma alloc_text(PAGE, UdfQueueClose)
#pragma alloc_text(PAGE, UdfRemoveClose)
#endif


VOID
UdfFspClose (
    IN PVCB Vcb OPTIONAL
    )

/*++

Routine Description:

    This routine is called to process the close queues in the UdfData.  If the
    Vcb is passed then we want to remove all of the closes for this Vcb.
    Otherwise we will do as many of the delayed closes as we need to do.

Arguments:

    Vcb - If specified then we are looking for all of the closes for the
        given Vcb.

Return Value:

    None

--*/

{
    PIRP_CONTEXT IrpContext;
    IRP_CONTEXT StackIrpContext;

    THREAD_CONTEXT ThreadContext;

    PFCB Fcb;
    ULONG UserReference;

    ULONG VcbHoldCount = 0;
    PVCB CurrentVcb = NULL;

    BOOLEAN ReleaseUdfData = FALSE;

    PAGED_CODE();

    //
    //  Check input.
    //

    ASSERT_OPTIONAL_VCB( Vcb );

    FsRtlEnterFileSystem();

    //
    //  Continue processing until there are no more closes to process.
    //

    while (IrpContext = UdfRemoveClose( Vcb )) {

        //
        //  If we don't have an IrpContext then use the one on the stack.
        //  Initialize it for this request.
        //

        if (SafeNodeType( IrpContext ) != UDFS_NTC_IRP_CONTEXT ) {

            //
            //  Update the local values from the IrpContextLite.
            //

            Fcb = ((PIRP_CONTEXT_LITE) IrpContext)->Fcb;
            UserReference = ((PIRP_CONTEXT_LITE) IrpContext)->UserReference;

            //
            //  Update the stack irp context with the values from the
            //  IrpContextLite.
            //

            UdfInitializeStackIrpContext( &StackIrpContext,
                                          (PIRP_CONTEXT_LITE) IrpContext );

            //
            //  Free the IrpContextLite.
            //

            UdfFreeIrpContextLite( (PIRP_CONTEXT_LITE) IrpContext );

            //
            //  Remember we have the IrpContext from the stack.
            //

            IrpContext = &StackIrpContext;

        //
        //  Otherwise cleanup the existing IrpContext.
        //

        } else {

            //
            //  Remember the Fcb and user reference count.
            //

            Fcb = (PFCB) IrpContext->Irp;
            IrpContext->Irp = NULL;

            UserReference = (ULONG) IrpContext->ExceptionStatus;
            IrpContext->ExceptionStatus = STATUS_SUCCESS;
        }

        //
        //  We have an IrpContext.  Now we need to set the top level thread
        //  context.
        //

        SetFlag( IrpContext->Flags, IRP_CONTEXT_FSP_FLAGS );

        //
        //  If we were given a Vcb then there is a request on top of this.
        //

        if (ARGUMENT_PRESENT( Vcb )) {

            ClearFlag( IrpContext->Flags,
                       IRP_CONTEXT_FLAG_TOP_LEVEL | IRP_CONTEXT_FLAG_TOP_LEVEL_UDFS );
        }

        UdfSetThreadContext( IrpContext, &ThreadContext );

        //
        //  If we have hit the maximum number of requests to process without
        //  releasing the Vcb then release the Vcb now.  If we are holding
        //  a different Vcb to this one then release the previous Vcb.
        //
        //  In either case acquire the current Vcb.
        //
        //  We use the MinDelayedCloseCount from the UdfData since it is
        //  a convenient value based on the system size.  Only thing we are trying
        //  to do here is prevent this routine starving other threads which
        //  may need this Vcb exclusively.
        //

        ReleaseUdfData = !ARGUMENT_PRESENT( Vcb ) &&
                         (Fcb->Vcb->VcbCondition != VcbMounted) &&
                         (Fcb->Vcb->VcbCondition != VcbMountInProgress) &&
                         (Fcb->Vcb->VcbCleanup == 0);

        if (ReleaseUdfData ||
            (VcbHoldCount > UdfData.MinDelayedCloseCount) ||
            (Fcb->Vcb != CurrentVcb)) {

            if (CurrentVcb != NULL) {

                UdfReleaseVcb( IrpContext, CurrentVcb );
            }

            if (ReleaseUdfData) {

                UdfAcquireUdfData( IrpContext );
            }

            CurrentVcb = Fcb->Vcb;
            UdfAcquireVcbShared( IrpContext, CurrentVcb, FALSE );

            VcbHoldCount = 0;

        } else {

            VcbHoldCount += 1;
        }

        DebugTrace(( +1, Dbg,
                     "UdfFspClose, Fcb %08x %4s Vcb %d/%d Fcb %d/%d\n",
                     Fcb,
                     ( UserReference? "USER" : "SYS" ),
                     CurrentVcb->VcbReference,
                     CurrentVcb->VcbUserReference,
                     Fcb->FcbReference,
                     Fcb->FcbUserReference ));

        //
        //  Call our worker routine to perform the close operation.
        //

        UdfCommonClosePrivate( IrpContext, CurrentVcb, Fcb, UserReference, FALSE );

        //
        //  If the reference count on this Vcb is below our residual reference
        //  then check if we should dismount the volume.
        //

        if (ReleaseUdfData) {

            UdfReleaseVcb( IrpContext, CurrentVcb );
            UdfCheckForDismount( IrpContext, CurrentVcb, FALSE );

            CurrentVcb = NULL;

            UdfReleaseUdfData( IrpContext );
            ReleaseUdfData = FALSE;
        }

        //
        //  Complete the current request to cleanup the IrpContext.
        //

        UdfCompleteRequest( IrpContext, NULL, STATUS_SUCCESS );

        DebugTrace(( -1, Dbg, "UdfFspClose -> VOID\n" ));
    }

    //
    //  Release any Vcb we may still hold.
    //

    if (CurrentVcb != NULL) {

        UdfReleaseVcb( IrpContext, CurrentVcb );
    }

    FsRtlExitFileSystem();
    return;
}


NTSTATUS
UdfCommonClose (
    IN PIRP_CONTEXT IrpContext,
    IN PIRP Irp
    )

/*++

Routine Description:

    This routine is the Fsd entry for the close operation.  We decode the file
    object to find the UDFS structures and type of open.  We call our internal
    worker routine to perform the actual work.  If the work wasn't completed
    then we post to one of our worker queues.  The Ccb isn't needed after this
    point so we delete the Ccb and return STATUS_SUCCESS to our caller in all
    cases.

Arguments:

    Irp - Supplies the Irp to process

Return Value:

    STATUS_SUCCESS

--*/

{
    TYPE_OF_OPEN TypeOfOpen;

    PVCB Vcb;
    PFCB Fcb;
    PCCB Ccb;
    ULONG UserReference = 0;

    BOOLEAN DelayedClose;
    BOOLEAN ReleaseUdfData = FALSE;

    PAGED_CODE();

    //
    //  Check input.
    //

    ASSERT_IRP_CONTEXT( IrpContext );
    ASSERT_IRP( Irp );

    //
    //  If we were called with our file system device object instead of a
    //  volume device object, just complete this request with STATUS_SUCCESS.
    //

    if (IrpContext->Vcb == NULL) {

        UdfCompleteRequest( IrpContext, Irp, STATUS_SUCCESS );
        return STATUS_SUCCESS;
    }

    //
    //  Decode the file object to get the type of open and Fcb/Ccb.
    //

    TypeOfOpen = UdfDecodeFileObject( IoGetCurrentIrpStackLocation( Irp )->FileObject,
                                      &Fcb,
                                      &Ccb );

    //
    //  No work to do for unopened file objects.
    //

    if (TypeOfOpen == UnopenedFileObject) {

        UdfCompleteRequest( IrpContext, Irp, STATUS_SUCCESS );

        return STATUS_SUCCESS;
    }

    Vcb = Fcb->Vcb;

    //
    //  Call the worker routine to perform the actual work.  This routine
    //  should never raise except for a fatal error.
    //

    if (Ccb != NULL) {

        UserReference = 1;

        //
        //  We can always deallocate the Ccb if present.
        //

        UdfDeleteCcb( IrpContext, Ccb );
    }

    //
    //  If this is a user file or directory then check if we should post
    //  this to the delayed close queue.  This has to be the last reference
    //  for a user file or directory open.
    //

    if ((Vcb->VcbCondition == VcbMounted) &&
        (Fcb->FcbReference == 1) &&
        ((TypeOfOpen == UserFileOpen) ||
         (TypeOfOpen == UserDirectoryOpen))) {

        UdfQueueClose( IrpContext, Fcb, UserReference, TRUE );
        IrpContext = NULL;

    //
    //  Otherwise try to process this close.  Post to the async close queue
    //  if we can't acquire all of the resources.
    //

    } else {

        //
        //  If we may be dismounting this volume then acquire the UdfData
        //  resource.
        //
	//  Since we now must make volumes go away as soon as reasonable after
	//  the last user handles closes, key off of the cleanup count.  It is
	//  OK to do this more than neccesary.  Since this Fcb could be holding
	//  a number of other Fcbs (and thus their references), a simple check
	//  on reference count is not appropriate.
        //

        if ((Vcb->VcbCleanup == 0) &&
            (Vcb->VcbCondition != VcbMounted) &&
            (Vcb->VcbCondition != VcbMountInProgress) &&
            FlagOn( IrpContext->Flags, IRP_CONTEXT_FLAG_TOP_LEVEL_UDFS )) {

            UdfAcquireUdfData( IrpContext );
            ReleaseUdfData = TRUE;
        }

        if (!UdfCommonClosePrivate( IrpContext, Vcb, Fcb, UserReference, TRUE )) {

            //
            //  If we didn't complete the request then post the request as needed.
            //

            UdfQueueClose( IrpContext, Fcb, UserReference, FALSE );
            IrpContext = NULL;

        //
        //  Check whether we should be dismounting the volume and then complete
        //  the request.
        //

        } else if (ReleaseUdfData) {

            UdfCheckForDismount( IrpContext, Vcb, FALSE );
        }
    }

    //
    //  Always complete this request with STATUS_SUCCESS.
    //

    UdfCompleteRequest( IrpContext, Irp, STATUS_SUCCESS );

    if (ReleaseUdfData) {

        UdfReleaseUdfData( IrpContext );
    }

    //
    //  Always return STATUS_SUCCESS for closes.
    //

    return STATUS_SUCCESS;
}