copy.c File Reference

#include <ntoskrnl.h>
#include <debug.h>

Include dependency graph for copy.c:

Go to the source code of this file.

Macros
#define	NDEBUG
#define	MAX_ZERO_LENGTH   (256 * 1024)

Typedefs
typedef enum _CC_CAN_WRITE_RETRY	CC_CAN_WRITE_RETRY

Enumerations
enum	_CC_CAN_WRITE_RETRY { FirstTry = 0, RetryAllowRemote = 253, RetryForceCheckPerFile = 254, RetryMasterLocked = 255 }

Functions
VOID NTAPI	MiZeroPhysicalPage (IN PFN_NUMBER PageFrameIndex)
VOID NTAPI	CcInitCacheZeroPage (VOID)
VOID	CcPostDeferredWrites (VOID)
VOID	CcPerformReadAhead (IN PFILE_OBJECT FileObject)
BOOLEAN NTAPI	CcCanIWrite (IN PFILE_OBJECT FileObject, IN ULONG BytesToWrite, IN BOOLEAN Wait, IN BOOLEAN Retrying)
static int	CcpCheckInvalidUserBuffer (PEXCEPTION_POINTERS Except, PVOID Buffer, ULONG Length)
BOOLEAN NTAPI	CcCopyRead (IN PFILE_OBJECT FileObject, IN PLARGE_INTEGER FileOffset, IN ULONG Length, IN BOOLEAN Wait, OUT PVOID Buffer, OUT PIO_STATUS_BLOCK IoStatus)
BOOLEAN NTAPI	CcCopyWrite (IN PFILE_OBJECT FileObject, IN PLARGE_INTEGER FileOffset, IN ULONG Length, IN BOOLEAN Wait, IN PVOID Buffer)
VOID NTAPI	CcDeferWrite (IN PFILE_OBJECT FileObject, IN PCC_POST_DEFERRED_WRITE PostRoutine, IN PVOID Context1, IN PVOID Context2, IN ULONG BytesToWrite, IN BOOLEAN Retrying)
VOID NTAPI	CcFastCopyRead (IN PFILE_OBJECT FileObject, IN ULONG FileOffset, IN ULONG Length, IN ULONG PageCount, OUT PVOID Buffer, OUT PIO_STATUS_BLOCK IoStatus)
VOID NTAPI	CcFastCopyWrite (IN PFILE_OBJECT FileObject, IN ULONG FileOffset, IN ULONG Length, IN PVOID Buffer)
BOOLEAN NTAPI	CcZeroData (IN PFILE_OBJECT FileObject, IN PLARGE_INTEGER StartOffset, IN PLARGE_INTEGER EndOffset, IN BOOLEAN Wait)

Variables
static PFN_NUMBER	CcZeroPage = 0
ULONG	CcRosTraceLevel = CC_API_DEBUG
ULONG	CcFastMdlReadWait
ULONG	CcFastMdlReadNotPossible
ULONG	CcFastReadNotPossible
ULONG	CcFastReadWait
ULONG	CcFastReadNoWait
ULONG	CcFastReadResourceMiss
ULONG	CcDataPages = 0
ULONG	CcDataFlushes = 0

Macro Definition Documentation

MAX_ZERO_LENGTH

#define MAX_ZERO_LENGTH   (256 * 1024)

Definition at line 21 of file copy.c.

NDEBUG

#define NDEBUG

Definition at line 14 of file copy.c.

Typedef Documentation

CC_CAN_WRITE_RETRY

typedef enum _CC_CAN_WRITE_RETRY CC_CAN_WRITE_RETRY

Enumeration Type Documentation

_CC_CAN_WRITE_RETRY

enum _CC_CAN_WRITE_RETRY

Enumerator
FirstTry
RetryAllowRemote
RetryForceCheckPerFile
RetryMasterLocked

Definition at line 23 of file copy.c.

{
    FirstTry = 0,
    RetryAllowRemote = 253,
    RetryForceCheckPerFile = 254,
    RetryMasterLocked = 255,
} CC_CAN_WRITE_RETRY;

Function Documentation

CcCanIWrite()

BOOLEAN NTAPI CcCanIWrite	(	IN PFILE_OBJECT	FileObject,
		IN ULONG	BytesToWrite,
		IN BOOLEAN	Wait,
		IN BOOLEAN	Retrying
	)

Definition at line 281 of file copy.c.

{
    KIRQL OldIrql;
    KEVENT WaitEvent;
    ULONG Length, Pages;
    BOOLEAN PerFileDefer;
    DEFERRED_WRITE Context;
    PFSRTL_COMMON_FCB_HEADER Fcb;
    CC_CAN_WRITE_RETRY TryContext;
    PROS_SHARED_CACHE_MAP SharedCacheMap;

    CCTRACE(CC_API_DEBUG, "FileObject=%p BytesToWrite=%lu Wait=%d Retrying=%d\n",
        FileObject, BytesToWrite, Wait, Retrying);

    /* Write through is always OK */
    if (BooleanFlagOn(FileObject->Flags, FO_WRITE_THROUGH))
    {
        return TRUE;
    }

    TryContext = Retrying;
    /* Allow remote file if not from posted */
    if (IoIsFileOriginRemote(FileObject) && TryContext < RetryAllowRemote)
    {
        return TRUE;
    }

    /* Don't exceed max tolerated size */
    Length = MAX_ZERO_LENGTH;
    if (BytesToWrite < MAX_ZERO_LENGTH)
    {
        Length = BytesToWrite;
    }

    Pages = BYTES_TO_PAGES(Length);

    /* By default, assume limits per file won't be hit */
    PerFileDefer = FALSE;
    Fcb = FileObject->FsContext;
    /* Do we have to check for limits per file? */
    if (TryContext >= RetryForceCheckPerFile ||
        BooleanFlagOn(Fcb->Flags, FSRTL_FLAG_LIMIT_MODIFIED_PAGES))
    {
        /* If master is not locked, lock it now */
        if (TryContext != RetryMasterLocked)
        {
            OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
        }

        /* Let's not assume the file is cached... */
        if (FileObject->SectionObjectPointer != NULL &&
            FileObject->SectionObjectPointer->SharedCacheMap != NULL)
        {
            SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;
            /* Do we have limits per file set? */
            if (SharedCacheMap->DirtyPageThreshold != 0 &&
                SharedCacheMap->DirtyPages != 0)
            {
                /* Yes, check whether they are blocking */
                if (Pages + SharedCacheMap->DirtyPages > SharedCacheMap->DirtyPageThreshold)
                {
                    PerFileDefer = TRUE;
                }
            }
        }

        /* And don't forget to release master */
        if (TryContext != RetryMasterLocked)
        {
            KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
        }
    }

    /* So, now allow write if:
     * - Not the first try or we have no throttling yet
     * AND:
     * - We don't exceed threshold!
     * - We don't exceed what Mm can allow us to use
     *   + If we're above top, that's fine
     *   + If we're above bottom with limited modified pages, that's fine
     *   + Otherwise, throttle!
     */
    if ((TryContext != FirstTry || IsListEmpty(&CcDeferredWrites)) &&
        CcTotalDirtyPages + Pages < CcDirtyPageThreshold &&
        (MmAvailablePages > MmThrottleTop ||
         (MmModifiedPageListHead.Total < 1000 && MmAvailablePages > MmThrottleBottom)) &&
        !PerFileDefer)
    {
        return TRUE;
    }

    /* If we can wait, we'll start the wait loop for waiting till we can
     * write for real
     */
    if (!Wait)
    {
        return FALSE;
    }

    /* Initialize our wait event */
    KeInitializeEvent(&WaitEvent, NotificationEvent, FALSE);

    /* And prepare a dummy context */
    Context.NodeTypeCode = NODE_TYPE_DEFERRED_WRITE;
    Context.NodeByteSize = sizeof(DEFERRED_WRITE);
    Context.FileObject = FileObject;
    Context.BytesToWrite = BytesToWrite;
    Context.LimitModifiedPages = BooleanFlagOn(Fcb->Flags, FSRTL_FLAG_LIMIT_MODIFIED_PAGES);
    Context.Event = &WaitEvent;

    /* And queue it */
    if (Retrying)
    {
        /* To the top, if that's a retry */
        ExInterlockedInsertHeadList(&CcDeferredWrites,
                                    &Context.DeferredWriteLinks,
                                    &CcDeferredWriteSpinLock);
    }
    else
    {
        /* To the bottom, if that's a first time */
        ExInterlockedInsertTailList(&CcDeferredWrites,
                                    &Context.DeferredWriteLinks,
                                    &CcDeferredWriteSpinLock);
    }

    /* Now make sure that the lazy scan writer will be active */
    OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
    if (!LazyWriter.ScanActive)
        CcScheduleLazyWriteScan(TRUE);
    KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);

#if DBG
    DPRINT1("Actively deferring write for: %p\n", FileObject);
    DPRINT1("Because:\n");
    if (CcTotalDirtyPages + Pages >= CcDirtyPageThreshold)
        DPRINT1("    There are too many cache dirty pages: %x + %x >= %x\n", CcTotalDirtyPages, Pages, CcDirtyPageThreshold);
    if (MmAvailablePages <= MmThrottleTop)
        DPRINT1("    Available pages are below throttle top: %lx <= %lx\n", MmAvailablePages, MmThrottleTop);
    if (MmModifiedPageListHead.Total >= 1000)
        DPRINT1("    There are too many modified pages: %lu >= 1000\n", MmModifiedPageListHead.Total);
    if (MmAvailablePages <= MmThrottleBottom)
        DPRINT1("    Available pages are below throttle bottom: %lx <= %lx\n", MmAvailablePages, MmThrottleBottom);
#endif
    /* Now, we'll loop until our event is set. When it is set, it means that caller
     * can immediately write, and has to
     */
    do
    {
        CcPostDeferredWrites();
    } while (KeWaitForSingleObject(&WaitEvent, Executive, KernelMode, FALSE, &CcIdleDelay) != STATUS_SUCCESS);

    return TRUE;
}

Referenced by CcPostDeferredWrites().

CcCopyRead()

BOOLEAN NTAPI CcCopyRead	(	IN PFILE_OBJECT	FileObject,
		IN PLARGE_INTEGER	FileOffset,
		IN ULONG	Length,
		IN BOOLEAN	Wait,
		OUT PVOID	Buffer,
		OUT PIO_STATUS_BLOCK	IoStatus
	)

Definition at line 465 of file copy.c.

{
    PROS_VACB Vacb;
    PROS_SHARED_CACHE_MAP SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;
    NTSTATUS Status;
    LONGLONG CurrentOffset;
    LONGLONG ReadEnd = FileOffset->QuadPart + Length;
    ULONG ReadLength = 0;

    CCTRACE(CC_API_DEBUG, "FileObject=%p FileOffset=%I64d Length=%lu Wait=%d\n",
        FileObject, FileOffset->QuadPart, Length, Wait);

    DPRINT("CcCopyRead(FileObject 0x%p, FileOffset %I64x, "
           "Length %lu, Wait %u, Buffer 0x%p, IoStatus 0x%p)\n",
           FileObject, FileOffset->QuadPart, Length, Wait,
           Buffer, IoStatus);

    if (!SharedCacheMap)
        return FALSE;

    /* Documented to ASSERT, but KMTests test this case... */
    // ASSERT((FileOffset->QuadPart + Length) <= SharedCacheMap->FileSize.QuadPart);

    CurrentOffset = FileOffset->QuadPart;
    while(CurrentOffset < ReadEnd)
    {
        Status = CcRosGetVacb(SharedCacheMap, CurrentOffset, &Vacb);
        if (!NT_SUCCESS(Status))
        {
            ExRaiseStatus(Status);
            return FALSE;
        }

        _SEH2_TRY
        {
            ULONG VacbOffset = CurrentOffset % VACB_MAPPING_GRANULARITY;
            ULONG VacbLength = min(Length, VACB_MAPPING_GRANULARITY - VacbOffset);
            SIZE_T CopyLength = VacbLength;

            if (!CcRosEnsureVacbResident(Vacb, Wait, FALSE, VacbOffset, VacbLength))
                return FALSE;

            _SEH2_TRY
            {
                RtlCopyMemory(Buffer, (PUCHAR)Vacb->BaseAddress + VacbOffset, CopyLength);
            }
            _SEH2_EXCEPT(CcpCheckInvalidUserBuffer(_SEH2_GetExceptionInformation(), Buffer, VacbLength))
            {
                ExRaiseStatus(STATUS_INVALID_USER_BUFFER);
            }
            _SEH2_END;

            ReadLength += VacbLength;

            Buffer = (PVOID)((ULONG_PTR)Buffer + VacbLength);
            CurrentOffset += VacbLength;
            Length -= VacbLength;
        }
        _SEH2_FINALLY
        {
            CcRosReleaseVacb(SharedCacheMap, Vacb, FALSE, FALSE);
        }
        _SEH2_END;
    }

    IoStatus->Status = STATUS_SUCCESS;
    IoStatus->Information = ReadLength;

#if 0
    /* If that was a successful sync read operation, let's handle read ahead */
    if (Length == 0 && Wait)
    {
        PPRIVATE_CACHE_MAP PrivateCacheMap = FileObject->PrivateCacheMap;

        /* If file isn't random access and next read may get us cross VACB boundary,
         * schedule next read
         */
        if (!BooleanFlagOn(FileObject->Flags, FO_RANDOM_ACCESS) &&
            (CurrentOffset - 1) / VACB_MAPPING_GRANULARITY != (CurrentOffset + ReadLength - 1) / VACB_MAPPING_GRANULARITY)
        {
            CcScheduleReadAhead(FileObject, FileOffset, ReadLength);
        }

        /* And update read history in private cache map */
        PrivateCacheMap->FileOffset1.QuadPart = PrivateCacheMap->FileOffset2.QuadPart;
        PrivateCacheMap->BeyondLastByte1.QuadPart = PrivateCacheMap->BeyondLastByte2.QuadPart;
        PrivateCacheMap->FileOffset2.QuadPart = FileOffset->QuadPart;
        PrivateCacheMap->BeyondLastByte2.QuadPart = FileOffset->QuadPart + ReadLength;
    }
#endif

    return TRUE;
}

Referenced by CcFastCopyRead().

CcCopyWrite()

BOOLEAN NTAPI CcCopyWrite	(	IN PFILE_OBJECT	FileObject,
		IN PLARGE_INTEGER	FileOffset,
		IN ULONG	Length,
		IN BOOLEAN	Wait,
		IN PVOID	Buffer
	)

Definition at line 570 of file copy.c.

{
    PROS_VACB Vacb;
    PROS_SHARED_CACHE_MAP SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;
    NTSTATUS Status;
    LONGLONG CurrentOffset;
    LONGLONG WriteEnd;

    CCTRACE(CC_API_DEBUG, "FileObject=%p FileOffset=%I64d Length=%lu Wait=%d Buffer=%p\n",
        FileObject, FileOffset->QuadPart, Length, Wait, Buffer);

    DPRINT("CcCopyWrite(FileObject 0x%p, FileOffset %I64x, "
           "Length %lu, Wait %u, Buffer 0x%p)\n",
           FileObject, FileOffset->QuadPart, Length, Wait, Buffer);

    if (!SharedCacheMap)
        return FALSE;

    Status = RtlLongLongAdd(FileOffset->QuadPart, Length, &WriteEnd);
    if (!NT_SUCCESS(Status))
        ExRaiseStatus(Status);

    ASSERT(WriteEnd <= SharedCacheMap->SectionSize.QuadPart);

    CurrentOffset = FileOffset->QuadPart;
    while(CurrentOffset < WriteEnd)
    {
        ULONG VacbOffset = CurrentOffset % VACB_MAPPING_GRANULARITY;
        ULONG VacbLength = min(WriteEnd - CurrentOffset, VACB_MAPPING_GRANULARITY - VacbOffset);

        Status = CcRosGetVacb(SharedCacheMap, CurrentOffset, &Vacb);
        if (!NT_SUCCESS(Status))
        {
            ExRaiseStatus(Status);
            return FALSE;
        }

        _SEH2_TRY
        {
            if (!CcRosEnsureVacbResident(Vacb, Wait, FALSE, VacbOffset, VacbLength))
            {
                return FALSE;
            }

            _SEH2_TRY
            {
                RtlCopyMemory((PVOID)((ULONG_PTR)Vacb->BaseAddress + VacbOffset), Buffer, VacbLength);
            }
            _SEH2_EXCEPT(CcpCheckInvalidUserBuffer(_SEH2_GetExceptionInformation(), Buffer, VacbLength))
            {
                ExRaiseStatus(STATUS_INVALID_USER_BUFFER);
            }
            _SEH2_END;

            Buffer = (PVOID)((ULONG_PTR)Buffer + VacbLength);
            CurrentOffset += VacbLength;

            /* Tell Mm */
            Status = MmMakePagesDirty(NULL, Add2Ptr(Vacb->BaseAddress, VacbOffset), VacbLength);
            if (!NT_SUCCESS(Status))
                ExRaiseStatus(Status);
        }
        _SEH2_FINALLY
        {
            /* Do not mark the VACB as dirty if an exception was raised */
            CcRosReleaseVacb(SharedCacheMap, Vacb, !_SEH2_AbnormalTermination(), FALSE);
        }
        _SEH2_END;
    }

    /* Flush if needed */
    if (FileObject->Flags & FO_WRITE_THROUGH)
        CcFlushCache(FileObject->SectionObjectPointer, FileOffset, Length, NULL);

    return TRUE;
}

Referenced by CcFastCopyWrite().

CcDeferWrite()

VOID NTAPI CcDeferWrite	(	IN PFILE_OBJECT	FileObject,
		IN PCC_POST_DEFERRED_WRITE	PostRoutine,
		IN PVOID	Context1,
		IN PVOID	Context2,
		IN ULONG	BytesToWrite,
		IN BOOLEAN	Retrying
	)

Definition at line 657 of file copy.c.

{
    KIRQL OldIrql;
    PDEFERRED_WRITE Context;
    PFSRTL_COMMON_FCB_HEADER Fcb;

    CCTRACE(CC_API_DEBUG, "FileObject=%p PostRoutine=%p Context1=%p Context2=%p BytesToWrite=%lu Retrying=%d\n",
        FileObject, PostRoutine, Context1, Context2, BytesToWrite, Retrying);

    /* Try to allocate a context for queueing the write operation */
    Context = ExAllocatePoolWithTag(NonPagedPool, sizeof(DEFERRED_WRITE), 'CcDw');
    /* If it failed, immediately execute the operation! */
    if (Context == NULL)
    {
        PostRoutine(Context1, Context2);
        return;
    }

    Fcb = FileObject->FsContext;

    /* Otherwise, initialize the context */
    RtlZeroMemory(Context, sizeof(DEFERRED_WRITE));
    Context->NodeTypeCode = NODE_TYPE_DEFERRED_WRITE;
    Context->NodeByteSize = sizeof(DEFERRED_WRITE);
    Context->FileObject = FileObject;
    Context->PostRoutine = PostRoutine;
    Context->Context1 = Context1;
    Context->Context2 = Context2;
    Context->BytesToWrite = BytesToWrite;
    Context->LimitModifiedPages = BooleanFlagOn(Fcb->Flags, FSRTL_FLAG_LIMIT_MODIFIED_PAGES);

    /* And queue it */
    if (Retrying)
    {
        /* To the top, if that's a retry */
        ExInterlockedInsertHeadList(&CcDeferredWrites,
                                    &Context->DeferredWriteLinks,
                                    &CcDeferredWriteSpinLock);
    }
    else
    {
        /* To the bottom, if that's a first time */
        ExInterlockedInsertTailList(&CcDeferredWrites,
                                    &Context->DeferredWriteLinks,
                                    &CcDeferredWriteSpinLock);
    }

    /* Try to execute the posted writes */
    CcPostDeferredWrites();

    /* Schedule a lazy writer run to handle deferred writes */
    OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
    if (!LazyWriter.ScanActive)
    {
        CcScheduleLazyWriteScan(FALSE);
    }
    KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
}

CcFastCopyRead()

VOID NTAPI CcFastCopyRead	(	IN PFILE_OBJECT	FileObject,
		IN ULONG	FileOffset,
		IN ULONG	Length,
		IN ULONG	PageCount,
		OUT PVOID	Buffer,
		OUT PIO_STATUS_BLOCK	IoStatus
	)

Definition at line 727 of file copy.c.

{
    LARGE_INTEGER LargeFileOffset;
    BOOLEAN Success;

    CCTRACE(CC_API_DEBUG, "FileObject=%p FileOffset=%lu Length=%lu PageCount=%lu Buffer=%p\n",
        FileObject, FileOffset, Length, PageCount, Buffer);

    DBG_UNREFERENCED_PARAMETER(PageCount);

    LargeFileOffset.QuadPart = FileOffset;
    Success = CcCopyRead(FileObject,
                         &LargeFileOffset,
                         Length,
                         TRUE,
                         Buffer,
                         IoStatus);
    ASSERT(Success == TRUE);
}

CcFastCopyWrite()

VOID NTAPI CcFastCopyWrite	(	IN PFILE_OBJECT	FileObject,
		IN ULONG	FileOffset,
		IN ULONG	Length,
		IN PVOID	Buffer
	)

Definition at line 758 of file copy.c.

{
    LARGE_INTEGER LargeFileOffset;
    BOOLEAN Success;

    CCTRACE(CC_API_DEBUG, "FileObject=%p FileOffset=%lu Length=%lu Buffer=%p\n",
        FileObject, FileOffset, Length, Buffer);

    LargeFileOffset.QuadPart = FileOffset;
    Success = CcCopyWrite(FileObject,
                          &LargeFileOffset,
                          Length,
                          TRUE,
                          Buffer);
    ASSERT(Success == TRUE);
}

CcInitCacheZeroPage()

VOID NTAPI CcInitCacheZeroPage

(

VOID

)

Definition at line 56 of file copy.c.

{
    NTSTATUS Status;

    MI_SET_USAGE(MI_USAGE_CACHE);
    //MI_SET_PROCESS2(PsGetCurrentProcess()->ImageFileName);
    Status = MmRequestPageMemoryConsumer(MC_SYSTEM, TRUE, &CcZeroPage);
    if (!NT_SUCCESS(Status))
    {
        DbgPrint("Can't allocate CcZeroPage.\n");
        KeBugCheck(CACHE_MANAGER);
    }
    MiZeroPhysicalPage(CcZeroPage);
}

Referenced by CcInitView().

CcpCheckInvalidUserBuffer()

static int CcpCheckInvalidUserBuffer ( PEXCEPTION_POINTERS  Except, PVOID  Buffer, ULONG  Length  )

static

Definition at line 442 of file copy.c.

{
    ULONG_PTR ExceptionAddress;
    ULONG_PTR BeginAddress = (ULONG_PTR)Buffer;
    ULONG_PTR EndAddress = (ULONG_PTR)Buffer + Length;

    if (Except->ExceptionRecord->ExceptionCode != STATUS_ACCESS_VIOLATION)
        return EXCEPTION_CONTINUE_SEARCH;
    if (Except->ExceptionRecord->NumberParameters < 2)
        return EXCEPTION_CONTINUE_SEARCH;

    ExceptionAddress = Except->ExceptionRecord->ExceptionInformation[1];
    if ((ExceptionAddress >= BeginAddress) && (ExceptionAddress < EndAddress))
        return EXCEPTION_EXECUTE_HANDLER;

    return EXCEPTION_CONTINUE_SEARCH;
}

Referenced by CcCopyRead(), and CcCopyWrite().

CcPerformReadAhead()

VOID CcPerformReadAhead

(

IN PFILE_OBJECT

FileObject

)

Definition at line 130 of file copy.c.

{
    NTSTATUS Status;
    LONGLONG CurrentOffset;
    KIRQL OldIrql;
    PROS_SHARED_CACHE_MAP SharedCacheMap;
    PROS_VACB Vacb;
    ULONG PartialLength;
    ULONG Length;
    PPRIVATE_CACHE_MAP PrivateCacheMap;
    BOOLEAN Locked;

    SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;

    /* Critical:
     * PrivateCacheMap might disappear in-between if the handle
     * to the file is closed (private is attached to the handle not to
     * the file), so we need to lock the master lock while we deal with
     * it. It won't disappear without attempting to lock such lock.
     */
    OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
    PrivateCacheMap = FileObject->PrivateCacheMap;
    /* If the handle was closed since the read ahead was scheduled, just quit */
    if (PrivateCacheMap == NULL)
    {
        KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
        ObDereferenceObject(FileObject);
        return;
    }
    /* Otherwise, extract read offset and length and release private map */
    else
    {
        KeAcquireSpinLockAtDpcLevel(&PrivateCacheMap->ReadAheadSpinLock);
        CurrentOffset = PrivateCacheMap->ReadAheadOffset[1].QuadPart;
        Length = PrivateCacheMap->ReadAheadLength[1];
        KeReleaseSpinLockFromDpcLevel(&PrivateCacheMap->ReadAheadSpinLock);
    }
    KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);

    /* Time to go! */
    DPRINT("Doing ReadAhead for %p\n", FileObject);
    /* Lock the file, first */
    if (!SharedCacheMap->Callbacks->AcquireForReadAhead(SharedCacheMap->LazyWriteContext, FALSE))
    {
        Locked = FALSE;
        goto Clear;
    }

    /* Remember it's locked */
    Locked = TRUE;

    /* Don't read past the end of the file */
    if (CurrentOffset >= SharedCacheMap->FileSize.QuadPart)
    {
        goto Clear;
    }
    if (CurrentOffset + Length > SharedCacheMap->FileSize.QuadPart)
    {
        Length = SharedCacheMap->FileSize.QuadPart - CurrentOffset;
    }

    /* Next of the algorithm will lock like CcCopyData with the slight
     * difference that we don't copy data back to an user-backed buffer
     * We just bring data into Cc
     */
    PartialLength = CurrentOffset % VACB_MAPPING_GRANULARITY;
    if (PartialLength != 0)
    {
        PartialLength = min(Length, VACB_MAPPING_GRANULARITY - PartialLength);
        Status = CcRosRequestVacb(SharedCacheMap,
                                  ROUND_DOWN(CurrentOffset, VACB_MAPPING_GRANULARITY),
                                  &Vacb);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("Failed to request VACB: %lx!\n", Status);
            goto Clear;
        }

        Status = CcRosEnsureVacbResident(Vacb, TRUE, FALSE,
                CurrentOffset % VACB_MAPPING_GRANULARITY, PartialLength);
        if (!NT_SUCCESS(Status))
        {
            CcRosReleaseVacb(SharedCacheMap, Vacb, FALSE, FALSE);
            DPRINT1("Failed to read data: %lx!\n", Status);
            goto Clear;
        }

        CcRosReleaseVacb(SharedCacheMap, Vacb, FALSE, FALSE);

        Length -= PartialLength;
        CurrentOffset += PartialLength;
    }

    while (Length > 0)
    {
        ASSERT(CurrentOffset % VACB_MAPPING_GRANULARITY == 0);
        PartialLength = min(VACB_MAPPING_GRANULARITY, Length);
        Status = CcRosRequestVacb(SharedCacheMap,
                                  CurrentOffset,
                                  &Vacb);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("Failed to request VACB: %lx!\n", Status);
            goto Clear;
        }

        Status = CcRosEnsureVacbResident(Vacb, TRUE, FALSE, 0, PartialLength);
        if (!NT_SUCCESS(Status))
        {
            CcRosReleaseVacb(SharedCacheMap, Vacb, FALSE, FALSE);
            DPRINT1("Failed to read data: %lx!\n", Status);
            goto Clear;
        }

        CcRosReleaseVacb(SharedCacheMap, Vacb, FALSE, FALSE);

        Length -= PartialLength;
        CurrentOffset += PartialLength;
    }

Clear:
    /* See previous comment about private cache map */
    OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
    PrivateCacheMap = FileObject->PrivateCacheMap;
    if (PrivateCacheMap != NULL)
    {
        /* Mark read ahead as unactive */
        KeAcquireSpinLockAtDpcLevel(&PrivateCacheMap->ReadAheadSpinLock);
        InterlockedAnd((volatile long *)&PrivateCacheMap->UlongFlags, ~PRIVATE_CACHE_MAP_READ_AHEAD_ACTIVE);
        KeReleaseSpinLockFromDpcLevel(&PrivateCacheMap->ReadAheadSpinLock);
    }
    KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);

    /* If file was locked, release it */
    if (Locked)
    {
        SharedCacheMap->Callbacks->ReleaseFromReadAhead(SharedCacheMap->LazyWriteContext);
    }

    /* And drop our extra reference (See: CcScheduleReadAhead) */
    ObDereferenceObject(FileObject);

    return;
}

Referenced by CcWorkerThread().

CcPostDeferredWrites()

VOID CcPostDeferredWrites

(

VOID

)

Definition at line 73 of file copy.c.

{
    LIST_ENTRY ToInsertBack;

    InitializeListHead(&ToInsertBack);

    /* We'll try to write as much as we can */
    while (TRUE)
    {
        PDEFERRED_WRITE DeferredWrite;
        PLIST_ENTRY ListEntry;

        DeferredWrite = NULL;

        ListEntry = ExInterlockedRemoveHeadList(&CcDeferredWrites, &CcDeferredWriteSpinLock);

        if (!ListEntry)
            break;

        DeferredWrite = CONTAINING_RECORD(ListEntry, DEFERRED_WRITE, DeferredWriteLinks);

        /* Check if we can write */
        if (CcCanIWrite(DeferredWrite->FileObject, DeferredWrite->BytesToWrite, FALSE, RetryForceCheckPerFile))
        {
            /* If we have an event, set it and go along */
            if (DeferredWrite->Event)
            {
                KeSetEvent(DeferredWrite->Event, IO_NO_INCREMENT, FALSE);
            }
            /* Otherwise, call the write routine and free the context */
            else
            {
                DeferredWrite->PostRoutine(DeferredWrite->Context1, DeferredWrite->Context2);
                ExFreePoolWithTag(DeferredWrite, 'CcDw');
            }
            continue;
        }

        /* Keep it for later */
        InsertHeadList(&ToInsertBack, &DeferredWrite->DeferredWriteLinks);

        /* If we don't accept modified pages, stop here */
        if (!DeferredWrite->LimitModifiedPages)
        {
            break;
        }
    }

    /* Insert what we couldn't write back in the list */
    while (!IsListEmpty(&ToInsertBack))
    {
        PLIST_ENTRY ListEntry = RemoveTailList(&ToInsertBack);
        ExInterlockedInsertHeadList(&CcDeferredWrites, ListEntry, &CcDeferredWriteSpinLock);
    }
}

Referenced by CcCanIWrite(), CcDeferWrite(), and CcLazyWriteScan().

CcZeroData()

BOOLEAN NTAPI CcZeroData	(	IN PFILE_OBJECT	FileObject,
		IN PLARGE_INTEGER	StartOffset,
		IN PLARGE_INTEGER	EndOffset,
		IN BOOLEAN	Wait
	)

Definition at line 784 of file copy.c.

{
    NTSTATUS Status;
    LARGE_INTEGER WriteOffset;
    LONGLONG Length;
    PROS_VACB Vacb;
    PROS_SHARED_CACHE_MAP SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;

    CCTRACE(CC_API_DEBUG, "FileObject=%p StartOffset=%I64u EndOffset=%I64u Wait=%d\n",
        FileObject, StartOffset->QuadPart, EndOffset->QuadPart, Wait);

    DPRINT("CcZeroData(FileObject 0x%p, StartOffset %I64x, EndOffset %I64x, "
           "Wait %u)\n", FileObject, StartOffset->QuadPart, EndOffset->QuadPart,
           Wait);

    Length = EndOffset->QuadPart - StartOffset->QuadPart;
    WriteOffset.QuadPart = StartOffset->QuadPart;

    if (!SharedCacheMap)
    {
        /* Make this a non-cached write */
        IO_STATUS_BLOCK Iosb;
        KEVENT Event;
        PMDL Mdl;
        ULONG i;
        ULONG CurrentLength;
        PPFN_NUMBER PfnArray;

        /* Setup our Mdl */
        Mdl = IoAllocateMdl(NULL, min(Length, MAX_ZERO_LENGTH), FALSE, FALSE, NULL);
        if (!Mdl)
            ExRaiseStatus(STATUS_INSUFFICIENT_RESOURCES);

        PfnArray = MmGetMdlPfnArray(Mdl);
        for (i = 0; i < BYTES_TO_PAGES(Mdl->ByteCount); i++)
            PfnArray[i] = CcZeroPage;
        Mdl->MdlFlags |= MDL_PAGES_LOCKED;

        /* Perform the write sequencially */
        while (Length > 0)
        {
            CurrentLength = min(Length, MAX_ZERO_LENGTH);

            Mdl->ByteCount = CurrentLength;

            KeInitializeEvent(&Event, NotificationEvent, FALSE);
            Status = IoSynchronousPageWrite(FileObject, Mdl, &WriteOffset, &Event, &Iosb);
            if (Status == STATUS_PENDING)
            {
                KeWaitForSingleObject(&Event, Executive, KernelMode, FALSE, NULL);
                Status = Iosb.Status;
            }
            if (Mdl->MdlFlags & MDL_MAPPED_TO_SYSTEM_VA)
            {
                MmUnmapLockedPages(Mdl->MappedSystemVa, Mdl);
            }
            if (!NT_SUCCESS(Status))
            {
                IoFreeMdl(Mdl);
                ExRaiseStatus(Status);
            }
            WriteOffset.QuadPart += CurrentLength;
            Length -= CurrentLength;
        }

        IoFreeMdl(Mdl);

        return TRUE;
    }

    /* See if we should simply truncate the valid data length */
    if ((StartOffset->QuadPart < SharedCacheMap->ValidDataLength.QuadPart) && (EndOffset->QuadPart >= SharedCacheMap->ValidDataLength.QuadPart))
    {
        DPRINT1("Truncating VDL.\n");
        SharedCacheMap->ValidDataLength = *StartOffset;
        return TRUE;
    }

    ASSERT(EndOffset->QuadPart <= SharedCacheMap->SectionSize.QuadPart);

    while(WriteOffset.QuadPart < EndOffset->QuadPart)
    {
        ULONG VacbOffset = WriteOffset.QuadPart % VACB_MAPPING_GRANULARITY;
        ULONG VacbLength = min(Length, VACB_MAPPING_GRANULARITY - VacbOffset);

        Status = CcRosGetVacb(SharedCacheMap, WriteOffset.QuadPart, &Vacb);
        if (!NT_SUCCESS(Status))
        {
            ExRaiseStatus(Status);
            return FALSE;
        }

        _SEH2_TRY
        {
            if (!CcRosEnsureVacbResident(Vacb, Wait, FALSE, VacbOffset, VacbLength))
            {
                return FALSE;
            }

            RtlZeroMemory((PVOID)((ULONG_PTR)Vacb->BaseAddress + VacbOffset), VacbLength);

            WriteOffset.QuadPart += VacbLength;
            Length -= VacbLength;

            /* Tell Mm */
            Status = MmMakePagesDirty(NULL, Add2Ptr(Vacb->BaseAddress, VacbOffset), VacbLength);
            if (!NT_SUCCESS(Status))
                ExRaiseStatus(Status);
        }
        _SEH2_FINALLY
        {
            /* Do not mark the VACB as dirty if an exception was raised */
            CcRosReleaseVacb(SharedCacheMap, Vacb, !_SEH2_AbnormalTermination(), FALSE);
        }
        _SEH2_END;
    }

    /* Flush if needed */
    if (FileObject->Flags & FO_WRITE_THROUGH)
        CcFlushCache(FileObject->SectionObjectPointer, StartOffset, EndOffset->QuadPart - StartOffset->QuadPart, NULL);

    return TRUE;
}

MiZeroPhysicalPage()

VOID NTAPI MiZeroPhysicalPage

(

IN PFN_NUMBER

PageFrameIndex

)

Definition at line 122 of file pfnlist.c.

{
    KIRQL OldIrql;
    PVOID VirtualAddress;
    PEPROCESS Process = PsGetCurrentProcess();

    /* Map in hyperspace, then wipe it using XMMI or MEMSET */
    VirtualAddress = MiMapPageInHyperSpace(Process, PageFrameIndex, &OldIrql);
    ASSERT(VirtualAddress);
    KeZeroPages(VirtualAddress, PAGE_SIZE);
    MiUnmapPageInHyperSpace(Process, VirtualAddress, OldIrql);
}

Referenced by CcInitCacheZeroPage(), MiAllocatePagesForMdl(), MiArchCreateProcessAddressSpace(), MiSessionCreateInternal(), MiSessionInitializeWorkingSetList(), and MmCreateProcessAddressSpace().

Variable Documentation

CcDataFlushes

ULONG CcDataFlushes = 0

Definition at line 44 of file copy.c.

Referenced by IoSynchronousPageWrite(), and QSI_DEF().

CcDataPages

ULONG CcDataPages = 0

Definition at line 43 of file copy.c.

Referenced by IoSynchronousPageWrite(), and QSI_DEF().

CcFastMdlReadNotPossible

ULONG CcFastMdlReadNotPossible

Definition at line 33 of file copy.c.

CcFastMdlReadWait

ULONG CcFastMdlReadWait

Definition at line 32 of file copy.c.

CcFastReadNotPossible

ULONG CcFastReadNotPossible

Definition at line 34 of file copy.c.

CcFastReadNoWait

ULONG CcFastReadNoWait

Definition at line 36 of file copy.c.

CcFastReadResourceMiss

ULONG CcFastReadResourceMiss

Definition at line 37 of file copy.c.

CcFastReadWait

ULONG CcFastReadWait

Definition at line 35 of file copy.c.

CcRosTraceLevel

ULONG CcRosTraceLevel = CC_API_DEBUG

Definition at line 31 of file copy.c.

CcZeroPage

PFN_NUMBER CcZeroPage = 0

static

Definition at line 19 of file copy.c.

Referenced by CcInitCacheZeroPage(), and CcZeroData().