cmcb.c

一个windows 文件系统驱动源码

/*
 * COPYRIGHT:        See COPYRIGHT.TXT
 * PROJECT:          Ext2 File System Driver for WinNT/2K/XP
 * FILE:             cmcb.c
 * PROGRAMMER:       Matt Wu <[e-mail]>
 * HOMEPAGE:         http://ext2.yeah.net
 * UPDATE HISTORY: 
 */

/* INCLUDES *****************************************************************/

#include "ntifs.h"
#include "ext2fs.h"

/* GLOBALS ***************************************************************/

extern PEXT2_GLOBAL g_gExt2Global;

/* DEFINITIONS *************************************************************/

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, Ext2AcquireForLazyWrite)
#pragma alloc_text(PAGE, Ext2ReleaseFromLazyWrite)
#pragma alloc_text(PAGE, Ext2AcquireForReadAhead)
#pragma alloc_text(PAGE, Ext2ReleaseFromReadAhead)
#pragma alloc_text(PAGE, Ext2NoOpRelease)
#pragma alloc_text(PAGE, Ext2NoOpRelease)
#endif


BOOLEAN
Ext2AcquireForLazyWrite (IN PVOID    Context,
             IN BOOLEAN  Wait)
{
    //
    // On a readonly filesystem this function still has to exist but it
    // doesn't need to do anything.
    
    PEXT2_FCB    Fcb;
    
    Fcb = (PEXT2_FCB) Context;
    
    ASSERT(Fcb != NULL);
    
    ASSERT((Fcb->Identifier.Type == EXT2FCB) &&
        (Fcb->Identifier.Size == sizeof(EXT2_FCB)));
#if DBG
    Ext2DbgPrint(D_CMCB, "Ext2AcquireForLazyWrite: %-16.16s %-31s %s\n",
        Ext2DbgGetCurrentProcessName(),
        "ACQUIRE_FOR_LAZY_WRITE",
        Fcb->AnsiFileName.Buffer        );
#endif
    
    if (!IsFlagOn(Fcb->Vcb->Flags, VCB_READ_ONLY))
    {
        if(!ExAcquireResourceExclusiveLite(
            &Fcb->PagingIoResource, Wait))
            return FALSE;
    }

    ASSERT(IoGetTopLevelIrp() == NULL);

    IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);

    return TRUE;
}

VOID
Ext2ReleaseFromLazyWrite (IN PVOID Context)
{
    //
    // On a readonly filesystem this function still has to exist but it
    // doesn't need to do anything.
    PEXT2_FCB Fcb;
    
    Fcb = (PEXT2_FCB) Context;
    
    ASSERT(Fcb != NULL);
    
    ASSERT((Fcb->Identifier.Type == EXT2FCB) &&
        (Fcb->Identifier.Size == sizeof(EXT2_FCB)));
#if DBG 
    Ext2DbgPrint(D_CMCB, "Ext2ReleaseFromLazyWrite: %-16.16s %-31s %s\n",
        Ext2DbgGetCurrentProcessName(),
        "RELEASE_FROM_LAZY_WRITE",
        Fcb->AnsiFileName.Buffer
        );
#endif

    if (!IsFlagOn(Fcb->Vcb->Flags, VCB_READ_ONLY))
    {
        ExReleaseResource(&Fcb->PagingIoResource);
    }

    ASSERT(IoGetTopLevelIrp() == (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);

    IoSetTopLevelIrp( NULL );

}

BOOLEAN
Ext2AcquireForReadAhead (IN PVOID    Context,
             IN BOOLEAN  Wait)
{
    PEXT2_FCB    Fcb;
    
    Fcb = (PEXT2_FCB) Context;
    
    ASSERT(Fcb != NULL);
    
    ASSERT((Fcb->Identifier.Type == EXT2FCB) &&
        (Fcb->Identifier.Size == sizeof(EXT2_FCB)));
#if DBG
    Ext2DbgPrint(D_CMCB, "Ext2AcquireForReadAhead: %-16.16s %-31s %s\n",
        Ext2DbgGetCurrentProcessName(),
        "ACQUIRE_FOR_READ_AHEAD",
        Fcb->AnsiFileName.Buffer        );
#endif

    if (!ExAcquireResourceShared(
        &Fcb->MainResource, Wait  ))
        return FALSE;

    ASSERT(IoGetTopLevelIrp() == NULL);

    IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);

    return TRUE;
}

VOID
Ext2ReleaseFromReadAhead (IN PVOID Context)
{
    PEXT2_FCB Fcb;
    
    Fcb = (PEXT2_FCB) Context;
    
    ASSERT(Fcb != NULL);
    
    ASSERT((Fcb->Identifier.Type == EXT2FCB) &&
        (Fcb->Identifier.Size == sizeof(EXT2_FCB)));
#if DBG
    Ext2DbgPrint(D_CMCB, "Ext2ReleaseFromReadAhead: %-16.16s %-31s %s\n",
        Ext2DbgGetCurrentProcessName(),
        "RELEASE_FROM_READ_AHEAD",
        Fcb->AnsiFileName.Buffer     );
#endif  

    IoSetTopLevelIrp( NULL );

    ExReleaseResource(&Fcb->MainResource);
}

BOOLEAN
Ext2NoOpAcquire (
    IN PVOID Fcb,
    IN BOOLEAN Wait
    )
{
    UNREFERENCED_PARAMETER( Fcb );
    UNREFERENCED_PARAMETER( Wait );

    //
    //  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....
    //

    ASSERT(IoGetTopLevelIrp() == NULL);

    IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);

    return TRUE;
}

VOID
Ext2NoOpRelease (
    IN PVOID Fcb
    )
{
    //
    //  Clear the kludge at this point.
    //

    ASSERT(IoGetTopLevelIrp() == (PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);

    IoSetTopLevelIrp( NULL );

    UNREFERENCED_PARAMETER( Fcb );

    return;
}