resrcsup.c File Reference

#include "fatprocs.h"

Include dependency graph for resrcsup.c:

Go to the source code of this file.

Functions
	_Requires_lock_held_ (_Global_critical_region_)
	_Function_class_ (FAST_IO_ACQUIRE_FOR_CCFLUSH)
BOOLEAN NTAPI	FatNoOpAcquire (IN PVOID Fcb, IN BOOLEAN Wait)
VOID NTAPI	FatNoOpRelease (IN PVOID Fcb)

Function Documentation

_Function_class_()

_Function_class_

(

FAST_IO_ACQUIRE_FOR_CCFLUSH

)

Definition at line 662 of file resrcsup.c.

{
    PFCB Fcb;
    PCCB Ccb;
    PVCB Vcb;
    PFSRTL_COMMON_FCB_HEADER Header;
    TYPE_OF_OPEN Type;
 
    PAGED_CODE();
    UNREFERENCED_PARAMETER( DeviceObject );
 
    //
    //  Once again, the hack for making this look like
    //  a recursive call if needed. We cannot let ourselves
    //  verify under something that has resources held.
    //
    //  This value is good.  We should never try to acquire
    //  the file this way underneath of the cache.
    //
 
    NT_ASSERT( IoGetTopLevelIrp() != (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP );
 
    if (IoGetTopLevelIrp() == NULL) {
 
        IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
    }
 
    //
    //  Time for some exposition.
    //
    //  Lockorder for FAT is main->bcb->pagingio. Invert this at your obvious peril.
    //  The default logic for AcquireForCcFlush breaks this since in writethrough
    //  unpinrepinned we will grab the bcb then Mm will use the callback (which
    //  orders us with respect to the MmCollidedFlushEvent) to help us. If for
    //  directories/ea we then grab the main we are out of order.
    //
    //  Fortunately, we do not need main. We only need paging - just look at the write
    //  path. This is basic pre-acquisition.
    //
    //  Regular files require both resources, and are safe since we never pin them.
    //
 
    //
    //  Note that we do not need to disable APC delivery to guard
    //  against a rogue user issuing a suspend APC. That is because
    //  it is guaranteed that the caller is either in the system context,
    //  to which a user cannot deliver a suspend APC, or the caller has
    //  already disabled kernel APC delivery before calling. This is true
    //  for all the other pre-acquire routines as well.
    //
 
    Type = FatDecodeFileObject( FileObject, &Vcb, &Fcb, &Ccb );
    Header = (PFSRTL_COMMON_FCB_HEADER) FileObject->FsContext;
 
    if (Type < DirectoryFile) {
 
        if (Header->Resource) {
 
            if (!ExIsResourceAcquiredSharedLite( Header->Resource )) {
 
                ExAcquireResourceExclusiveLite( Header->Resource, TRUE );
 
            } else {
 
                ExAcquireResourceSharedLite( Header->Resource, TRUE );
            }
        }
    }
 
    if (Header->PagingIoResource) {
 
        ExAcquireResourceSharedLite( Header->PagingIoResource, TRUE );
    }
 
    return STATUS_SUCCESS;
}

_Requires_lock_held_()

_Requires_lock_held_

(

_Global_critical_region_

)

Definition at line 35 of file resrcsup.c.

{
    PAGED_CODE();
 
#ifdef _MSC_VER
#pragma prefast( suppress: 28137, "prefast wants the wait to be a constant, but that isn't possible for the way fastfat is designed" )
#endif
    if (ExAcquireResourceExclusiveLite( &Vcb->Resource, BooleanFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT))) {
 
        if (!NoOpCheck) {
 
            _SEH2_TRY {
 
                FatVerifyOperationIsLegal( IrpContext );
 
            } _SEH2_FINALLY {
 
                if ( _SEH2_AbnormalTermination() ) {
 
                    FatReleaseVcb( IrpContext, Vcb );
                }
            } _SEH2_END;
        }
 
        return TRUE;
    }
 
    return FALSE;
}

FatNoOpAcquire()

BOOLEAN NTAPI FatNoOpAcquire	(	IN PVOID	Fcb,
		IN BOOLEAN	Wait
	)

Definition at line 795 of file resrcsup.c.

{
    UNREFERENCED_PARAMETER( Fcb );
    UNREFERENCED_PARAMETER( Wait );
 
    PAGED_CODE();
 
    //
    //  This is a kludge because Cc is really the top level.  We it
    //  enters the file system, we will think it is a resursive call
    //  and complete the request with hard errors or verify.  It will
    //  have to deal with them, somehow....
    //
 
    NT_ASSERT(IoGetTopLevelIrp() == NULL);
 
    IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
 
    return TRUE;
}

FatNoOpRelease()

VOID NTAPI FatNoOpRelease

(

IN PVOID

Fcb

)

Definition at line 842 of file resrcsup.c.

{
    PAGED_CODE();
 
    //
    //  Clear the kludge at this point.
    //
 
    NT_ASSERT(IoGetTopLevelIrp() == (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
 
    IoSetTopLevelIrp( NULL );
 
    UNREFERENCED_PARAMETER( Fcb );
 
    return;
}