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346 lines
6.8 KiB
346 lines
6.8 KiB
/*++
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Copyright (c) 1996-2000 Microsoft Corporation
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Module Name:
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ResrcSup.c
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Abstract:
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This module implements the Udfs Resource acquisition routines
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// @@BEGIN_DDKSPLIT
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Author:
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Dan Lovinger [DanLo] 10-Jul-1996
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Tom Jolly [tomjolly] 21-Jan-2000
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Revision History:
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// @@END_DDKSPLIT
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--*/
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#include "UdfProcs.h"
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//
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// The Bug check file id for this module
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//
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#define BugCheckFileId (UDFS_BUG_CHECK_RESRCSUP)
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//
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// The local debug trace level
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//
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#define Dbg (UDFS_DEBUG_LEVEL_RESRCSUP)
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(PAGE, UdfAcquireForCache)
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#pragma alloc_text(PAGE, UdfAcquireForCreateSection)
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#pragma alloc_text(PAGE, UdfAcquireResource)
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#pragma alloc_text(PAGE, UdfNoopAcquire)
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#pragma alloc_text(PAGE, UdfNoopRelease)
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#pragma alloc_text(PAGE, UdfReleaseForCreateSection)
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#pragma alloc_text(PAGE, UdfReleaseFromCache)
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#endif
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BOOLEAN
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UdfAcquireResource (
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IN PIRP_CONTEXT IrpContext,
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IN PERESOURCE Resource,
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IN BOOLEAN IgnoreWait,
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IN TYPE_OF_ACQUIRE Type
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)
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/*++
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Routine Description:
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This is the single routine used to acquire file system resources. It
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looks at the IgnoreWait flag to determine whether to try to acquire the
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resource without waiting. Returning TRUE/FALSE to indicate success or
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failure. Otherwise it is driven by the WAIT flag in the IrpContext and
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will raise CANT_WAIT on a failure.
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Arguments:
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Resource - This is the resource to try and acquire.
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IgnoreWait - If TRUE then this routine will not wait to acquire the
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resource and will return a boolean indicating whether the resource was
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acquired. Otherwise we use the flag in the IrpContext and raise
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if the resource is not acquired.
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Type - Indicates how we should try to get the resource.
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Return Value:
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BOOLEAN - TRUE if the resource is acquired. FALSE if not acquired and
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IgnoreWait is specified. Otherwise we raise CANT_WAIT.
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--*/
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{
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BOOLEAN Wait = FALSE;
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BOOLEAN Acquired;
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PAGED_CODE();
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//
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// We look first at the IgnoreWait flag, next at the flag in the Irp
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// Context to decide how to acquire this resource.
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//
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if (!IgnoreWait && FlagOn( IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT )) {
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Wait = TRUE;
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}
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//
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// Attempt to acquire the resource either shared or exclusively.
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//
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switch (Type) {
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case AcquireExclusive:
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Acquired = ExAcquireResourceExclusiveLite( Resource, Wait );
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break;
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case AcquireShared:
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Acquired = ExAcquireResourceSharedLite( Resource, Wait );
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break;
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case AcquireSharedStarveExclusive:
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Acquired = ExAcquireSharedStarveExclusive( Resource, Wait );
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break;
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default:
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ASSERT( FALSE );
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Acquired = FALSE;
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}
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//
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// If not acquired and the user didn't specifiy IgnoreWait then
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// raise CANT_WAIT.
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//
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if (!Acquired && !IgnoreWait) {
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UdfRaiseStatus( IrpContext, STATUS_CANT_WAIT );
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}
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return Acquired;
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}
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BOOLEAN
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UdfAcquireForCache (
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IN PFCB Fcb,
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IN BOOLEAN Wait
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)
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/*++
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Routine Description:
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The address of this routine is specified when creating a CacheMap for
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a file. It is subsequently called by the Lazy Writer for synchronization.
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Arguments:
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Fcb - The pointer supplied as context to the cache initialization
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routine.
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Wait - TRUE if the caller is willing to block.
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Return Value:
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None
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--*/
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{
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PAGED_CODE();
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ASSERT(IoGetTopLevelIrp() == NULL);
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IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
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return ExAcquireResourceSharedLite( Fcb->Resource, Wait );
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}
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VOID
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UdfReleaseFromCache (
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IN PFCB Fcb
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)
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/*++
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Routine Description:
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The address of this routine is specified when creating a CacheMap for
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a virtual file. It is subsequently called by the Lazy Writer to release
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a resource acquired above.
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Arguments:
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Fcb - The pointer supplied as context to the cache initialization
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routine.
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Return Value:
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None
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--*/
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{
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PAGED_CODE();
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ASSERT(IoGetTopLevelIrp() == (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
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IoSetTopLevelIrp( NULL );
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ExReleaseResourceLite( Fcb->Resource );
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}
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BOOLEAN
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UdfNoopAcquire (
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IN PVOID Fcb,
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IN BOOLEAN Wait
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)
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/*++
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Routine Description:
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This routine does nothing.
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Arguments:
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Fcb - The Fcb/Vcb which was specified as a context parameter for this
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routine.
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Wait - TRUE if the caller is willing to block.
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Return Value:
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TRUE
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--*/
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{
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PAGED_CODE();
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return TRUE;
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}
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VOID
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UdfNoopRelease (
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IN PVOID Fcb
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)
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/*++
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Routine Description:
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This routine does nothing.
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Arguments:
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Fcb - The Fcb/Vcb which was specified as a context parameter for this
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routine.
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Return Value:
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None
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--*/
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{
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PAGED_CODE();
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}
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VOID
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UdfAcquireForCreateSection (
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IN PFILE_OBJECT FileObject
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)
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/*++
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Routine Description:
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This is the callback routine for MM to use to acquire the file exclusively.
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Arguments:
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FileObject - File object for a Udffs stream.
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Return Value:
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None
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--*/
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{
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PAGED_CODE();
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//
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// Get the Fcb resource exclusively.
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//
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ExAcquireResourceExclusiveLite( &((PFCB) FileObject->FsContext)->FcbNonpaged->FcbResource,
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TRUE );
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//
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// Take the File resource shared. We need this later on when MM calls
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// QueryStandardInfo to get the file size.
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//
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// If we don't use StarveExclusive, then we can get wedged behind an
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// exclusive waiter who is waiting on someone else holding it shared in the
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// read->initializecachemap path (which calls createsection) who is in turn
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// waiting on us to finish the create section.
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//
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ExAcquireSharedStarveExclusive( ((PFCB) FileObject->FsContext)->Resource,
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TRUE );
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}
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VOID
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UdfReleaseForCreateSection (
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IN PFILE_OBJECT FileObject
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)
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/*++
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Routine Description:
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This is the callback routine for MM to use to release a file acquired with
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the AcquireForCreateSection call above.
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Arguments:
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FileObject - File object for a Udffs stream.
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Return Value:
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None
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--*/
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{
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PAGED_CODE();
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//
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// Release the resources.
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//
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ExReleaseResourceLite( &((PFCB) FileObject->FsContext)->FcbNonpaged->FcbResource );
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ExReleaseResourceLite( ((PFCB) FileObject->FsContext)->Resource );
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}
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