cachesup.c

winddk src目录下的文件系统驱动源码压缩!

/*++

Copyright (c) 1990-2000 Microsoft Corporation

Module Name:

    cache.c

Abstract:

    This module implements the cache management routines for the Fat
    FSD and FSP, by calling the Common Cache Manager.


--*/

#include "FatProcs.h"

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

#define BugCheckFileId                   (FAT_BUG_CHECK_CACHESUP)

//
//  Local debug trace level
//

#define Dbg                              (DEBUG_TRACE_CACHESUP)

#if DBG

BOOLEAN
FatIsCurrentOperationSynchedForDcbTeardown (
    IN PIRP_CONTEXT IrpContext,
    IN PDCB Dcb
    );

#endif

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, FatCloseEaFile)
#pragma alloc_text(PAGE, FatCompleteMdl)
#pragma alloc_text(PAGE, FatOpenDirectoryFile)
#pragma alloc_text(PAGE, FatOpenEaFile)
#pragma alloc_text(PAGE, FatPinMappedData)
#pragma alloc_text(PAGE, FatPrepareWriteDirectoryFile)
#pragma alloc_text(PAGE, FatPrepareWriteVolumeFile)
#pragma alloc_text(PAGE, FatReadDirectoryFile)
#pragma alloc_text(PAGE, FatReadVolumeFile)
#pragma alloc_text(PAGE, FatRepinBcb)
#pragma alloc_text(PAGE, FatSyncUninitializeCacheMap)
#pragma alloc_text(PAGE, FatUnpinRepinnedBcbs)
#pragma alloc_text(PAGE, FatZeroData)
#if DBG
#pragma alloc_text(PAGE, FatIsCurrentOperationSynchedForDcbTeardown)
#endif
#endif


VOID
FatReadVolumeFile (
    IN PIRP_CONTEXT IrpContext,
    IN PVCB Vcb,
    IN VBO StartingVbo,
    IN ULONG ByteCount,
    OUT PBCB *Bcb,
    OUT PVOID *Buffer
    )

/*++

Routine Description:

    This routine is called when the specified range of sectors is to be
    read into the cache.  In fat, the volume file only contains the boot
    sector, reserved sectors, and the "fat(s)."  Thus the volume file is
    of fixed size and only extends up to (but not not including) the root
    directory entry, and will never move or change size.

    The fat volume file is also peculiar in that, since it starts at the
    logical beginning of the disk, Vbo == Lbo.

Arguments:

    Vcb - Pointer to the VCB for the volume

    StartingVbo - The virtual offset of the first desired byte

    ByteCount - Number of bytes desired

    Bcb - Returns a pointer to the BCB which is valid until unpinned

    Buffer - Returns a pointer to the sectors, which is valid until unpinned

--*/

{
    LARGE_INTEGER Vbo;

    PAGED_CODE();

    //
    //  Check to see that all references are within the Bios Parameter Block
    //  or the fat(s).  A special case is made when StartingVbo == 0 at
    //  mounting time since we do not know how big the fat is.
    //

    ASSERT( ((StartingVbo == 0) || ((StartingVbo + ByteCount) <= (ULONG)
            (FatRootDirectoryLbo( &Vcb->Bpb ) + PAGE_SIZE))));

    DebugTrace(+1, Dbg, "FatReadVolumeFile\n", 0);
    DebugTrace( 0, Dbg, "Vcb         = %08lx\n", Vcb);
    DebugTrace( 0, Dbg, "StartingVbo = %08lx\n", StartingVbo);
    DebugTrace( 0, Dbg, "ByteCount   = %08lx\n", ByteCount);

    //
    //  Call the Cache manager to attempt the transfer.
    //

    Vbo.QuadPart = StartingVbo;

    if (!CcMapData( Vcb->VirtualVolumeFile,
                    &Vbo,
                    ByteCount,
                    BooleanFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT),
                    Bcb,
                    Buffer )) {

        ASSERT( !FlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT) );

        //
        // Could not read the data without waiting (cache miss).
        //

        FatRaiseStatus( IrpContext, STATUS_CANT_WAIT );
    }

    DbgDoit( IrpContext->PinCount += 1 )

    DebugTrace(-1, Dbg, "FatReadVolumeFile -> VOID, *BCB = %08lx\n", *Bcb);

    return;
}


VOID
FatPrepareWriteVolumeFile (
    IN PIRP_CONTEXT IrpContext,
    IN PVCB Vcb,
    IN VBO StartingVbo,
    IN ULONG ByteCount,
    OUT PBCB *Bcb,
    OUT PVOID *Buffer,
    IN BOOLEAN Reversible,
    IN BOOLEAN Zero
    )

/*++

Routine Description:

    This routine first looks to see if the specified range of sectors,
    is already in the cache.  If so, it increments the BCB PinCount,
    sets the BCB dirty, and returns with the location of the sectors.

    If the sectors are not in the cache and Wait is TRUE, it finds a
    free BCB (potentially causing a flush), and clears out the entire
    buffer.  Once this is done, it increments the BCB PinCount, sets the
    BCB dirty, and returns with the location of the sectors.

    If the sectors are not in the cache and Wait is FALSE, this routine
    raises STATUS_CANT_WAIT.

Arguments:

    Vcb - Pointer to the VCB for the volume

    StartingVbo - The virtual offset of the first byte to be written

    ByteCount - Number of bytes to be written

    Bcb - Returns a pointer to the BCB which is valid until unpinned

    Buffer - Returns a pointer to the sectors, which is valid until unpinned

    Reversible - Supplies TRUE if the specified range of modification should
        be repinned so that the operation can be reversed in a controlled
        fashion if errors are encountered.
    
    Zero - Supplies TRUE if the specified range of bytes should be zeroed

--*/

{
    LARGE_INTEGER Vbo;

    PAGED_CODE();
    
    //
    //  Check to see that all references are within the Bios Parameter Block
    //  or the fat(s).
    //

    ASSERT( ((StartingVbo + ByteCount) <= (ULONG)
            (FatRootDirectoryLbo( &Vcb->Bpb ))));

    DebugTrace(+1, Dbg, "FatPrepareWriteVolumeFile\n", 0);
    DebugTrace( 0, Dbg, "Vcb         = %08lx\n", Vcb);
    DebugTrace( 0, Dbg, "StartingVbo = %08lx\n", (ULONG)StartingVbo);
    DebugTrace( 0, Dbg, "ByteCount   = %08lx\n", ByteCount);
    DebugTrace( 0, Dbg, "Zero        = %08lx\n", Zero);

    //
    //  Call the Cache manager to attempt the transfer.
    //

    Vbo.QuadPart = StartingVbo;

    if (!CcPinRead( Vcb->VirtualVolumeFile,
                    &Vbo,
                    ByteCount,
                    BooleanFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT),
                    Bcb,
                    Buffer )) {

        ASSERT( !FlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT) );

        //
        // Could not read the data without waiting (cache miss).
        //

        FatRaiseStatus( IrpContext, STATUS_CANT_WAIT );
    }

    //
    //  This keeps the data pinned until we complete the request
    //  and writes the dirty bit through to the disk.
    //

    DbgDoit( IrpContext->PinCount += 1 )

    try {

        if (Zero) {
            
            RtlZeroMemory( *Buffer, ByteCount );
        }

        FatSetDirtyBcb( IrpContext, *Bcb, Vcb, Reversible );

    } finally {

        if (AbnormalTermination()) {

            FatUnpinBcb(IrpContext, *Bcb);
        }
    }

    DebugTrace(-1, Dbg, "FatPrepareWriteVolumeFile -> VOID, *Bcb = %08lx\n", *Bcb);

    return;
}


VOID
FatReadDirectoryFile (
    IN PIRP_CONTEXT IrpContext,
    IN PDCB Dcb,
    IN VBO StartingVbo,
    IN ULONG ByteCount,
    IN BOOLEAN Pin,
    OUT PBCB *Bcb,
    OUT PVOID *Buffer,
    OUT PNTSTATUS Status
    )

/*++

Routine Description:

    This routine is called when the specified range of sectors is to be
    read into the cache.  If the desired range falls beyond the current
    cache mapping, the fat will be searched, and if the desired range can
    be satisfied, the cache mapping will be extended and the MCB updated
    accordingly.

Arguments:

    Dcb - Pointer to the DCB for the directory

    StartingVbo - The virtual offset of the first desired byte

    ByteCount - Number of bytes desired

    Pin - Tells us if we should pin instead of just mapping.

    Bcb - Returns a pointer to the BCB which is valid until unpinned

    Buffer - Returns a pointer to the sectors, which is valid until unpinned

    Status - Returns the status of the operation.

--*/

{
    LARGE_INTEGER Vbo;

    PAGED_CODE();
    
    DebugTrace(+1, Dbg, "FatReadDirectoryFile\n", 0);
    DebugTrace( 0, Dbg, "Dcb         = %08lx\n", Dcb);
    DebugTrace( 0, Dbg, "StartingVbo = %08lx\n", StartingVbo);
    DebugTrace( 0, Dbg, "ByteCount   = %08lx\n", ByteCount);

    //
    //  Check for the zero case
    //

    if (ByteCount == 0) {

        DebugTrace(0, Dbg, "Nothing to read\n", 0);

        *Bcb = NULL;
        *Buffer = NULL;
        *Status = STATUS_SUCCESS;

        DebugTrace(-1, Dbg, "FatReadDirectoryFile -> VOID\n", 0);
        return;
    }

    //
    //  If we need to create a directory file and initialize the
    //  cachemap, do so.
    //

    FatOpenDirectoryFile( IrpContext, Dcb );

    //
    //  Now if the transfer is beyond the allocation size return EOF.
    //

    if (StartingVbo >= Dcb->Header.AllocationSize.LowPart) {

        DebugTrace(0, Dbg, "End of file read for directory\n", 0);

        *Bcb = NULL;
        *Buffer = NULL;
        *Status = STATUS_END_OF_FILE;

        DebugTrace(-1, Dbg, "FatReadDirectoryFile -> VOID\n", 0);
        return;
    }

    //
    // If the caller is trying to read past the EOF, truncate the
    // read.
    //

    ByteCount = (Dcb->Header.AllocationSize.LowPart - StartingVbo < ByteCount) ?
                 Dcb->Header.AllocationSize.LowPart - StartingVbo : ByteCount;

    ASSERT( ByteCount != 0 );

    //
    //  Call the Cache manager to attempt the transfer.
    //

    Vbo.QuadPart = StartingVbo;

    if (Pin ?

        !CcPinRead( Dcb->Specific.Dcb.DirectoryFile,
                    &Vbo,
                    ByteCount,
                    BooleanFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT),
                    Bcb,
                    Buffer )
        :

        !CcMapData( Dcb->Specific.Dcb.DirectoryFile,
                    &Vbo,
                    ByteCount,
                    BooleanFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT),
                    Bcb,
                    Buffer ) ) {

        //
        // Could not read the data without waiting (cache miss).
        //

        *Bcb = NULL;
        *Buffer = NULL;
        FatRaiseStatus( IrpContext, STATUS_CANT_WAIT );
    }

    DbgDoit( IrpContext->PinCount += 1 )

    *Status = STATUS_SUCCESS;

    DebugTrace(-1, Dbg, "FatReadDirectoryFile -> VOID, *BCB = %08lx\n", *Bcb);

    return;
}


VOID
FatPrepareWriteDirectoryFile (
    IN PIRP_CONTEXT IrpContext,
    IN PDCB Dcb,
    IN VBO StartingVbo,
    IN ULONG ByteCount,
    OUT PBCB *Bcb,
    OUT PVOID *Buffer,
    IN BOOLEAN Zero,
    IN BOOLEAN Reversible,
    OUT PNTSTATUS Status
    )

/*++

Routine Description:

    This routine first looks to see if the specified range of sectors
    is already in the cache.  If so, it increments the BCB PinCount,
    sets the BCB dirty, and returns TRUE with the location of the sectors.

    The IrpContext->Flags .. Wait == TRUE/FALSE actions of this routine are identical to
    FatPrepareWriteVolumeFile() above.

Arguments:

    Dcb - Pointer to the DCB for the directory

    StartingVbo - The virtual offset of the first byte to be written

    ByteCount - Number of bytes to be written

    Bcb - Returns a pointer to the BCB which is valid until unpinned

    Buffer - Returns a pointer to the sectors, which is valid until unpinned

    Zero - Supplies TRUE if the specified range of bytes should be zeroed
    
    Reversible - Supplies TRUE if the specified range of modification should
        be repinned so that the operation can be reversed in a controlled
        fashion if errors are encountered.