read.cpp File Reference

#include "udffs.h"

Include dependency graph for read.cpp:

Go to the source code of this file.

Macros
#define	UDF_BUG_CHECK_ID   UDF_FILE_READ
#define	OVERFLOW_READ_THRESHHOLD   (0x1000)
#define	UDF_REQ_NOT_VIA_CACHE_MGR(ptr)   (!MmIsRecursiveIoFault() && ((ptr)->ImageSectionObject != NULL))

Functions
NTSTATUS NTAPI	UDFRead (PDEVICE_OBJECT DeviceObject, PIRP Irp)
NTSTATUS	UDFPostStackOverflowRead (IN PtrUDFIrpContext PtrIrpContext, IN PIRP Irp, IN PtrUDFFCB Fcb)
VOID NTAPI	UDFStackOverflowRead (IN PVOID Context, IN PKEVENT Event)
NTSTATUS	UDFCommonRead (PtrUDFIrpContext PtrIrpContext, PIRP Irp)
PVOID	UDFGetCallersBuffer (PtrUDFIrpContext PtrIrpContext, PIRP Irp)
NTSTATUS	UDFLockCallersBuffer (PtrUDFIrpContext PtrIrpContext, PIRP Irp, BOOLEAN IsReadOperation, uint32 Length)
NTSTATUS	UDFUnlockCallersBuffer (PtrUDFIrpContext PtrIrpContext, PIRP Irp, PVOID SystemBuffer)
VOID	UDFMdlComplete (PtrUDFIrpContext PtrIrpContext, PIRP Irp, PIO_STACK_LOCATION IrpSp, BOOLEAN ReadCompletion)

Macro Definition Documentation

OVERFLOW_READ_THRESHHOLD

#define OVERFLOW_READ_THRESHHOLD   (0x1000)

Definition at line 29 of file read.cpp.

UDF_BUG_CHECK_ID

#define UDF_BUG_CHECK_ID   UDF_FILE_READ

Definition at line 20 of file read.cpp.

UDF_REQ_NOT_VIA_CACHE_MGR

#define UDF_REQ_NOT_VIA_CACHE_MGR

(

ptr

)

(!MmIsRecursiveIoFault() && ((ptr)->ImageSectionObject != NULL))

Function Documentation

UDFCommonRead()

NTSTATUS UDFCommonRead	(	PtrUDFIrpContext	PtrIrpContext,
		PIRP	Irp
	)

Definition at line 229 of file read.cpp.

{
    NTSTATUS                RC = STATUS_SUCCESS;
    PIO_STACK_LOCATION      IrpSp = NULL;
    LARGE_INTEGER           ByteOffset;
    ULONG                   ReadLength = 0, TruncatedLength = 0;
    SIZE_T                  NumberBytesRead = 0;
    PFILE_OBJECT            FileObject = NULL;
    PtrUDFFCB               Fcb = NULL;
    PtrUDFCCB               Ccb = NULL;
    PVCB                    Vcb = NULL;
    PtrUDFNTRequiredFCB     NtReqFcb = NULL;
    PERESOURCE              PtrResourceAcquired = NULL;
    PERESOURCE              PtrResourceAcquired2 = NULL;
    PVOID                   SystemBuffer = NULL;
    PIRP                    TopIrp;
//    uint32                  KeyValue = 0;

    ULONG                   Res1Acq = 0;
    ULONG                   Res2Acq = 0;

    BOOLEAN                 CacheLocked = FALSE;

    BOOLEAN                 CanWait = FALSE;
    BOOLEAN                 PagingIo = FALSE;
    BOOLEAN                 NonBufferedIo = FALSE;
    BOOLEAN                 SynchronousIo = FALSE;

    TmPrint(("UDFCommonRead: irp %x\n", Irp));

    _SEH2_TRY {

        TopIrp = IoGetTopLevelIrp();
        switch((ULONG_PTR)TopIrp) {
        case FSRTL_FSP_TOP_LEVEL_IRP:
            UDFPrint(("  FSRTL_FSP_TOP_LEVEL_IRP\n"));
            break;
        case FSRTL_CACHE_TOP_LEVEL_IRP:
            UDFPrint(("  FSRTL_CACHE_TOP_LEVEL_IRP\n"));
            break;
        case FSRTL_MOD_WRITE_TOP_LEVEL_IRP:
            UDFPrint(("  FSRTL_MOD_WRITE_TOP_LEVEL_IRP\n"));
//            BrutePoint()
            break;
        case FSRTL_FAST_IO_TOP_LEVEL_IRP:
            UDFPrint(("  FSRTL_FAST_IO_TOP_LEVEL_IRP\n"));
//            BrutePoint()
            break;
        case NULL:
            UDFPrint(("  NULL TOP_LEVEL_IRP\n"));
            break;
        default:
            if(TopIrp == Irp) {
                UDFPrint(("  TOP_LEVEL_IRP\n"));
            } else {
                UDFPrint(("  RECURSIVE_IRP, TOP = %x\n", TopIrp));
            }
            break;
        }
        // First, get a pointer to the current I/O stack location
        IrpSp = IoGetCurrentIrpStackLocation(Irp);
        ASSERT(IrpSp);
        MmPrint(("    Enter Irp, MDL=%x\n", Irp->MdlAddress));
        if(Irp->MdlAddress) {
            UDFTouch(Irp->MdlAddress);
        }

        // If this happens to be a MDL read complete request, then
        // there is not much processing that the FSD has to do.
        if (IrpSp->MinorFunction & IRP_MN_COMPLETE) {
            // Caller wants to tell the Cache Manager that a previously
            // allocated MDL can be freed.
            UDFMdlComplete(PtrIrpContext, Irp, IrpSp, TRUE);
            // The IRP has been completed.
            try_return(RC = STATUS_SUCCESS);
        }

        // If this is a request at IRQL DISPATCH_LEVEL, then post
        // the request (your FSD may choose to process it synchronously
        // if you implement the support correctly; obviously you will be
        // quite constrained in what you can do at such IRQL).
        if (IrpSp->MinorFunction & IRP_MN_DPC) {
            try_return(RC = STATUS_PENDING);
        }

        FileObject = IrpSp->FileObject;
        ASSERT(FileObject);

        // Get the FCB and CCB pointers
        Ccb = (PtrUDFCCB)(FileObject->FsContext2);
        ASSERT(Ccb);
        Fcb = Ccb->Fcb;
        ASSERT(Fcb);
        Vcb = Fcb->Vcb;

        if(Fcb->FCBFlags & UDF_FCB_DELETED) {
            ASSERT(FALSE);
            try_return(RC = STATUS_ACCESS_DENIED);
        }

        // check for stack overflow
        if (IoGetRemainingStackSize() < OVERFLOW_READ_THRESHHOLD) {
            RC = UDFPostStackOverflowRead( PtrIrpContext, Irp, Fcb );
            try_return(RC);
        }

        // Disk based file systems might decide to verify the logical volume
        //  (if required and only if removable media are supported) at this time
        // As soon as Tray is locked, we needn't call UDFVerifyVcb()

        ByteOffset = IrpSp->Parameters.Read.ByteOffset;

        CanWait = (PtrIrpContext->IrpContextFlags & UDF_IRP_CONTEXT_CAN_BLOCK) ? TRUE : FALSE;
        PagingIo = (Irp->Flags & IRP_PAGING_IO) ? TRUE : FALSE;
        NonBufferedIo = (Irp->Flags & IRP_NOCACHE) ? TRUE : FALSE;
        SynchronousIo = (FileObject->Flags & FO_SYNCHRONOUS_IO) ? TRUE : FALSE;
        UDFPrint(("    Flags: %s %s %s %s\n",
                      CanWait ? "W" : "w", PagingIo ? "Pg" : "pg",
                      NonBufferedIo ? "NBuf" : "buff", SynchronousIo ? "Snc" : "Asc"));

        if(!NonBufferedIo &&
           (Fcb->NodeIdentifier.NodeType != UDF_NODE_TYPE_VCB)) {
            if(UDFIsAStream(Fcb->FileInfo)) {
                UDFNotifyFullReportChange( Vcb, Fcb->FileInfo,
                                           FILE_NOTIFY_CHANGE_LAST_ACCESS,
                                           FILE_ACTION_MODIFIED_STREAM);
            } else {
                UDFNotifyFullReportChange( Vcb, Fcb->FileInfo,
                                           FILE_NOTIFY_CHANGE_LAST_ACCESS,
                                           FILE_ACTION_MODIFIED);
            }
        }

        // Get some of the parameters supplied to us
        ReadLength = IrpSp->Parameters.Read.Length;
        if (ReadLength == 0) {
            // a 0 byte read can be immediately succeeded
            try_return(RC);
        }
        UDFPrint(("    ByteOffset = %I64x, ReadLength = %x\n", ByteOffset.QuadPart, ReadLength));

        // Is this a read of the volume itself ?
        if (Fcb->NodeIdentifier.NodeType == UDF_NODE_TYPE_VCB) {
            // Yup, we need to send this on to the disk driver after
            //  validation of the offset and length.
            Vcb = (PVCB)Fcb;
            Vcb->VCBFlags |= UDF_VCB_SKIP_EJECT_CHECK;
            if(!CanWait)
                try_return(RC = STATUS_PENDING);


            if(PtrIrpContext->IrpContextFlags & UDF_IRP_CONTEXT_FLUSH2_REQUIRED) {

                UDFPrint(("  UDF_IRP_CONTEXT_FLUSH2_REQUIRED\n"));
                PtrIrpContext->IrpContextFlags &= ~UDF_IRP_CONTEXT_FLUSH2_REQUIRED;

                if(!(Vcb->VCBFlags & UDF_VCB_FLAGS_RAW_DISK)) {
                    UDFCloseAllSystemDelayedInDir(Vcb, Vcb->RootDirFCB->FileInfo);
                }
#ifdef UDF_DELAYED_CLOSE
                UDFCloseAllDelayed(Vcb);
#endif //UDF_DELAYED_CLOSE

            }

            if(PtrIrpContext->IrpContextFlags & UDF_IRP_CONTEXT_FLUSH_REQUIRED) {

                UDFPrint(("  UDF_IRP_CONTEXT_FLUSH_REQUIRED\n"));
                PtrIrpContext->IrpContextFlags &= ~UDF_IRP_CONTEXT_FLUSH_REQUIRED;

                // Acquire the volume resource exclusive
                UDFAcquireResourceExclusive(&(Vcb->VCBResource), TRUE);
                PtrResourceAcquired = &(Vcb->VCBResource);

                UDFFlushLogicalVolume(NULL, NULL, Vcb, 0);

                UDFReleaseResource(PtrResourceAcquired);
                PtrResourceAcquired = NULL;
            }

            // Acquire the volume resource shared ...
            UDFAcquireResourceShared(&(Vcb->VCBResource), TRUE);
            PtrResourceAcquired = &(Vcb->VCBResource);

#if 0
            if(PagingIo) {
                CollectStatistics(Vcb, MetaDataReads);
                CollectStatisticsEx(Vcb, MetaDataReadBytes, NumberBytesRead);
            }
#endif

            // Forward the request to the lower level driver
            // Lock the callers buffer
            if (!NT_SUCCESS(RC = UDFLockCallersBuffer(PtrIrpContext, Irp, TRUE, ReadLength))) {
                try_return(RC);
            }
            SystemBuffer = UDFGetCallersBuffer(PtrIrpContext, Irp);
            if(!SystemBuffer) {
                try_return(RC = STATUS_INVALID_USER_BUFFER);
            }
            if(Vcb->VCBFlags & UDF_VCB_FLAGS_VOLUME_MOUNTED) {
                 RC = UDFReadData(Vcb, TRUE, ByteOffset.QuadPart,
                                ReadLength, FALSE, (PCHAR)SystemBuffer,
                                &NumberBytesRead);
            } else {
                 RC = UDFTRead(Vcb, SystemBuffer, ReadLength,
                                (ULONG)(ByteOffset.QuadPart >> Vcb->BlockSizeBits),
                                &NumberBytesRead);
            }
            UDFUnlockCallersBuffer(PtrIrpContext, Irp, SystemBuffer);
            try_return(RC);
        }
        Vcb->VCBFlags |= UDF_VCB_SKIP_EJECT_CHECK;

        // If the read request is directed to a page file (if your FSD
        // supports paging files), send the request directly to the disk
        // driver. For requests directed to a page file, you have to trust
        // that the offsets will be set correctly by the VMM. You should not
        // attempt to acquire any FSD resources either.
        if(Fcb->FCBFlags & UDF_FCB_PAGE_FILE) {
            NonBufferedIo = TRUE;
        }

        if(ByteOffset.HighPart == -1) {
            if(ByteOffset.LowPart == FILE_USE_FILE_POINTER_POSITION) {
                ByteOffset = FileObject->CurrentByteOffset;
            }
        }

        // If this read is directed to a directory, it is not allowed
        //  by the UDF FSD.
        if(Fcb->FCBFlags & UDF_FCB_DIRECTORY) {
            RC = STATUS_INVALID_DEVICE_REQUEST;
            try_return(RC);
        }

        NtReqFcb = Fcb->NTRequiredFCB;

        Res1Acq = UDFIsResourceAcquired(&(NtReqFcb->MainResource));
        if(!Res1Acq) {
            Res1Acq = PtrIrpContext->IrpContextFlags & UDF_IRP_CONTEXT_RES1_ACQ;
        }
        Res2Acq = UDFIsResourceAcquired(&(NtReqFcb->PagingIoResource));
        if(!Res2Acq) {
            Res2Acq = PtrIrpContext->IrpContextFlags & UDF_IRP_CONTEXT_RES2_ACQ;
        }

#if 0
        if(PagingIo) {
            CollectStatistics(Vcb, UserFileReads);
            CollectStatisticsEx(Vcb, UserFileReadBytes, NumberBytesRead);
        }
#endif

        // This is a good place for oplock related processing.

        // If this is the normal file we have to check for
        // write access according to the current state of the file locks.
        if (!PagingIo &&
            !FsRtlCheckLockForReadAccess( &(NtReqFcb->FileLock), Irp )) {
                try_return( RC = STATUS_FILE_LOCK_CONFLICT );
        }

        // Validate start offset and length supplied.
        //  If start offset is > end-of-file, return an appropriate error. Note
        // that since a FCB resource has already been acquired, and since all
        // file size changes require acquisition of both FCB resources,
        // the contents of the FCB and associated data structures
        // can safely be examined.

        //  Also note that we are using the file size in the "Common FCB Header"
        // to perform the check. However, your FSD might decide to keep a
        // separate copy in the FCB (or some other representation of the
        //  file associated with the FCB).

        TruncatedLength = ReadLength;
        if (ByteOffset.QuadPart >= NtReqFcb->CommonFCBHeader.FileSize.QuadPart) {
            // Starting offset is >= file size
            try_return(RC = STATUS_END_OF_FILE);
        }
        // We can also go ahead and truncate the read length here
        //  such that it is contained within the file size
        if( NtReqFcb->CommonFCBHeader.FileSize.QuadPart < (ByteOffset.QuadPart + ReadLength) ) {
            TruncatedLength = (ULONG)(NtReqFcb->CommonFCBHeader.FileSize.QuadPart - ByteOffset.QuadPart);
            // we can't get ZERO here
        }
        UDFPrint(("    TruncatedLength = %x\n", TruncatedLength));

        // There are certain complications that arise when the same file stream
        // has been opened for cached and non-cached access. The FSD is then
        // responsible for maintaining a consistent view of the data seen by
        // the caller.
        // Also, it is possible for file streams to be mapped in both as data files
        // and as an executable. This could also lead to consistency problems since
        // there now exist two separate sections (and pages) containing file
        // information.

        // The test below flushes the data cached in system memory if the current
        // request madates non-cached access (file stream must be cached) and
        // (a) the current request is not paging-io which indicates it is not
        //       a recursive I/O operation OR originating in the Cache Manager
        // (b) OR the current request is paging-io BUT it did not originate via
        //       the Cache Manager (or is a recursive I/O operation) and we do
        //       have an image section that has been initialized.
#define UDF_REQ_NOT_VIA_CACHE_MGR(ptr)  (!MmIsRecursiveIoFault() && ((ptr)->ImageSectionObject != NULL))

        if(NonBufferedIo &&
           (NtReqFcb->SectionObject.DataSectionObject != NULL)) {
            if(!PagingIo) {

/*                // We hold the main resource exclusive here because the flush
                // may generate a recursive write in this thread.  The PagingIo
                // resource is held shared so the drop-and-release serialization
                // below will work.
                if(!UDFAcquireResourceExclusive(&(NtReqFcb->MainResource), CanWait)) {
                    try_return(RC = STATUS_PENDING);
                }
                PtrResourceAcquired = &(NtReqFcb->MainResource);

                // We hold PagingIo shared around the flush to fix a
                // cache coherency problem.
                UDFAcquireResourceShared(&(NtReqFcb->PagingIoResource), TRUE );*/

                MmPrint(("    CcFlushCache()\n"));
                CcFlushCache(&(NtReqFcb->SectionObject), &ByteOffset, TruncatedLength, &(Irp->IoStatus));

/*                UDFReleaseResource(&(NtReqFcb->PagingIoResource));
                UDFReleaseResource(PtrResourceAcquired);
                PtrResourceAcquired = NULL;
                // If the flush failed, return error to the caller
                if(!NT_SUCCESS(RC = Irp->IoStatus.Status)) {
                    try_return(RC);
                }

                // Acquiring and immediately dropping the resource serializes
                // us behind any other writes taking place (either from the
                // lazy writer or modified page writer).*/
                if(!Res2Acq) {
                    UDFAcquireResourceExclusive(&(NtReqFcb->PagingIoResource), TRUE );
                    UDFReleaseResource(&(NtReqFcb->PagingIoResource));
                }
            }
        }
    
        // Acquire the appropriate FCB resource shared
        if (PagingIo) {
            // Try to acquire the FCB PagingIoResource shared
            if(!Res2Acq) {
                if (!UDFAcquireResourceShared(&(NtReqFcb->PagingIoResource), CanWait)) {
                    try_return(RC = STATUS_PENDING);
                }
                // Remember the resource that was acquired
                PtrResourceAcquired2 = &(NtReqFcb->PagingIoResource);
            }
        } else {
            // Try to acquire the FCB MainResource shared
            if(NonBufferedIo) {
                if(!Res2Acq) {
                    if(!UDFAcquireSharedWaitForExclusive(&(NtReqFcb->PagingIoResource), CanWait)) {
                        try_return(RC = STATUS_PENDING);
                    }
                    PtrResourceAcquired2 = &(NtReqFcb->PagingIoResource);
                }
            } else {
                if(!Res1Acq) {
                    UDF_CHECK_PAGING_IO_RESOURCE(NtReqFcb);
                    if(!UDFAcquireResourceShared(&(NtReqFcb->MainResource), CanWait)) {
                        try_return(RC = STATUS_PENDING);
                    }
                    // Remember the resource that was acquired
                    PtrResourceAcquired = &(NtReqFcb->MainResource);
                }
            }
        }

        // This is also a good place to set whether fast-io can be performed
        // on this particular file or not. Your FSD must make it's own
        // determination on whether or not to allow fast-io operations.
        // Commonly, fast-io is not allowed if any byte range locks exist
        // on the file or if oplocks prevent fast-io. Practically any reason
        // choosen by your FSD could result in your setting FastIoIsNotPossible
        // OR FastIoIsQuestionable instead of FastIoIsPossible.

        NtReqFcb->CommonFCBHeader.IsFastIoPossible = UDFIsFastIoPossible(Fcb);
/*        if(NtReqFcb->CommonFCBHeader.IsFastIoPossible == FastIoIsPossible)
            NtReqFcb->CommonFCBHeader.IsFastIoPossible = FastIoIsQuestionable;*/

#ifdef UDF_DISABLE_SYSTEM_CACHE_MANAGER
        NonBufferedIo = TRUE;
#endif

        if(Fcb && Fcb->FileInfo && Fcb->FileInfo->Dloc) {
            AdPrint(("UDFCommonRead: DataLoc %x, Mapping %x\n", &Fcb->FileInfo->Dloc->DataLoc, Fcb->FileInfo->Dloc->DataLoc.Mapping));
        }

        //  Branch here for cached vs non-cached I/O
        if (!NonBufferedIo) {

            if(FileObject->Flags & FO_WRITE_THROUGH) {
                CanWait = TRUE;
            }
            // The caller wishes to perform cached I/O. Initiate caching if
            // this is the first cached I/O operation using this file object
            if (!(FileObject->PrivateCacheMap)) {
                // This is the first cached I/O operation. You must ensure
                // that the FCB Common FCB Header contains valid sizes at this time
                MmPrint(("    CcInitializeCacheMap()\n"));
                CcInitializeCacheMap(FileObject, (PCC_FILE_SIZES)(&(NtReqFcb->CommonFCBHeader.AllocationSize)),
                    FALSE,      // We will not utilize pin access for this file
                    &(UDFGlobalData.CacheMgrCallBacks), // callbacks
                    NtReqFcb);        // The context used in callbacks
                MmPrint(("    CcSetReadAheadGranularity()\n"));
                CcSetReadAheadGranularity(FileObject, Vcb->SystemCacheGran);
            }

            // Check and see if this request requires a MDL returned to the caller
            if (IrpSp->MinorFunction & IRP_MN_MDL) {
                // Caller does want a MDL returned. Note that this mode
                // implies that the caller is prepared to block
                MmPrint(("    CcMdlRead()\n"));
//                CcMdlRead(FileObject, &ByteOffset, TruncatedLength, &(Irp->MdlAddress), &(Irp->IoStatus));
//                NumberBytesRead = Irp->IoStatus.Information;
//                RC = Irp->IoStatus.Status;
                NumberBytesRead = 0;
                RC = STATUS_INVALID_PARAMETER;

                try_return(RC);
            }

            // This is a regular run-of-the-mill cached I/O request. Let the
            // Cache Manager worry about it!
            // First though, we need a buffer pointer (address) that is valid
            SystemBuffer = UDFGetCallersBuffer(PtrIrpContext, Irp);
            if(!SystemBuffer)
                try_return(RC = STATUS_INVALID_USER_BUFFER);
            ASSERT(SystemBuffer);
            MmPrint(("    CcCopyRead()\n"));
            if (!CcCopyRead(FileObject, &(ByteOffset), TruncatedLength, CanWait, SystemBuffer, &(Irp->IoStatus))) {
                // The caller was not prepared to block and data is not immediately
                // available in the system cache
                try_return(RC = STATUS_PENDING);
            }

            UDFUnlockCallersBuffer(PtrIrpContext, Irp, SystemBuffer);
            // We have the data
            RC = Irp->IoStatus.Status;
            NumberBytesRead = Irp->IoStatus.Information;

            try_return(RC);

        } else {

            MmPrint(("    Read NonBufferedIo\n"));

#if 1
            if((ULONG_PTR)TopIrp == FSRTL_MOD_WRITE_TOP_LEVEL_IRP) {
                UDFPrint(("FSRTL_MOD_WRITE_TOP_LEVEL_IRP => CanWait\n"));
                CanWait = TRUE;
            } else
            if((ULONG_PTR)TopIrp == FSRTL_CACHE_TOP_LEVEL_IRP) {
                UDFPrint(("FSRTL_CACHE_TOP_LEVEL_IRP => CanWait\n"));
                CanWait = TRUE;
            }

            if(NtReqFcb->AcqSectionCount || NtReqFcb->AcqFlushCount) {
                MmPrint(("    AcqCount (%d/%d)=> CanWait ?\n", NtReqFcb->AcqSectionCount, NtReqFcb->AcqFlushCount));
                CanWait = TRUE;
            } else
            {}
/*            if((TopIrp != Irp)) {
                UDFPrint(("(TopIrp != Irp) => CanWait\n"));
                CanWait = TRUE;
            } else*/
#endif
            if(KeGetCurrentIrql() > PASSIVE_LEVEL) {
                MmPrint(("    !PASSIVE_LEVEL\n"));
                CanWait = FALSE;
                PtrIrpContext->IrpContextFlags |= UDF_IRP_CONTEXT_FORCED_POST;
            }
            if(!CanWait && UDFIsFileCached__(Vcb, Fcb->FileInfo, ByteOffset.QuadPart, TruncatedLength, FALSE)) {
                MmPrint(("    Locked => CanWait\n"));
                CacheLocked = TRUE;
                CanWait = TRUE;
            }

            // Send the request to lower level drivers
            if(!CanWait) {
                try_return(RC = STATUS_PENDING);
            }

//                ASSERT(NT_SUCCESS(RC));
            if(!Res2Acq) {
                if(UDFAcquireResourceSharedWithCheck(&(NtReqFcb->PagingIoResource)))
                    PtrResourceAcquired2 = &(NtReqFcb->PagingIoResource);
            }

            RC = UDFLockCallersBuffer(PtrIrpContext, Irp, TRUE, TruncatedLength);
            if(!NT_SUCCESS(RC)) {
                try_return(RC);
            }

            SystemBuffer = UDFGetCallersBuffer(PtrIrpContext, Irp);
            if(!SystemBuffer) {
                try_return(RC = STATUS_INVALID_USER_BUFFER);
            }

            RC = UDFReadFile__(Vcb, Fcb->FileInfo, ByteOffset.QuadPart, TruncatedLength,
                           CacheLocked, (PCHAR)SystemBuffer, &NumberBytesRead);
/*                // AFAIU, CacheManager wants this:
            if(!NT_SUCCESS(RC)) {
                NumberBytesRead = 0;
            }*/

            UDFUnlockCallersBuffer(PtrIrpContext, Irp, SystemBuffer);

#if 0
            if(PagingIo) {
                CollectStatistics(Vcb, UserDiskReads);
            } else {
                CollectStatistics2(Vcb, NonCachedDiskReads);
            }
#endif

            try_return(RC);

            // For paging-io, the FSD has to trust the VMM to do the right thing

            // Here is a common method used by Windows NT native file systems
            // that are in the process of sending a request to the disk driver.
            // First, mark the IRP as pending, then invoke the lower level driver
            // after setting a completion routine.
            // Meanwhile, this particular thread can immediately return a
            // STATUS_PENDING return code.
            // The completion routine is then responsible for completing the IRP
            // and unlocking appropriate resources

            // Also, at this point, the FSD might choose to utilize the
            // information contained in the ValidDataLength field to simply
            // return zeroes to the caller for reads extending beyond current
            // valid data length.

        }

try_exit:   NOTHING;

    } _SEH2_FINALLY {

        if(CacheLocked) {
            WCacheEODirect__(&(Vcb->FastCache), Vcb);
        }

        // Release any resources acquired here ...
        if(PtrResourceAcquired2) {
            UDFReleaseResource(PtrResourceAcquired2);
        }
        if(PtrResourceAcquired) {
            if(NtReqFcb &&
               (PtrResourceAcquired ==
                &(NtReqFcb->MainResource))) {
                UDF_CHECK_PAGING_IO_RESOURCE(NtReqFcb);
            }
            UDFReleaseResource(PtrResourceAcquired);
        }

        // Post IRP if required
        if(RC == STATUS_PENDING) {

            // Lock the callers buffer here. Then invoke a common routine to
            // perform the post operation.
            if (!(IrpSp->MinorFunction & IRP_MN_MDL)) {
                RC = UDFLockCallersBuffer(PtrIrpContext, Irp, TRUE, ReadLength);
                ASSERT(NT_SUCCESS(RC));
            }
            if(PagingIo) {
                if(Res1Acq) {
                    PtrIrpContext->IrpContextFlags |= UDF_IRP_CONTEXT_RES1_ACQ;
                }
                if(Res2Acq) {
                    PtrIrpContext->IrpContextFlags |= UDF_IRP_CONTEXT_RES2_ACQ;
                }
            }
            // Perform the post operation which will mark the IRP pending
            // and will return STATUS_PENDING back to us
            RC = UDFPostRequest(PtrIrpContext, Irp);

        } else {
            // For synchronous I/O, the FSD must maintain the current byte offset
            // Do not do this however, if I/O is marked as paging-io
            if (SynchronousIo && !PagingIo && NT_SUCCESS(RC)) {
                FileObject->CurrentByteOffset.QuadPart = ByteOffset.QuadPart + NumberBytesRead;
            }
            // If the read completed successfully and this was not a paging-io
            // operation, set a flag in the CCB that indicates that a read was
            // performed and that the file time should be updated at cleanup
            if (NT_SUCCESS(RC) && !PagingIo) {
                FileObject->Flags |= FO_FILE_FAST_IO_READ;
                Ccb->CCBFlags |= UDF_CCB_ACCESSED;
            }

            if(!_SEH2_AbnormalTermination()) {
                Irp->IoStatus.Status = RC;
                Irp->IoStatus.Information = NumberBytesRead;
                UDFPrint(("    NumberBytesRead = %x\n", NumberBytesRead));
                // Free up the Irp Context
                UDFReleaseIrpContext(PtrIrpContext);
                // complete the IRP
                MmPrint(("    Complete Irp, MDL=%x\n", Irp->MdlAddress));
                if(Irp->MdlAddress) {
                    UDFTouch(Irp->MdlAddress);
                }
                IoCompleteRequest(Irp, IO_DISK_INCREMENT);
            }
        } // can we complete the IRP ?
    } _SEH2_END; // end of "__finally" processing

    return(RC);
} // end UDFCommonRead()

Referenced by UDFCommonDispatch(), UDFRead(), and UDFStackOverflowRead().

UDFGetCallersBuffer()

PVOID UDFGetCallersBuffer	(	PtrUDFIrpContext	PtrIrpContext,
		PIRP	Irp
	)

Definition at line 871 of file read.cpp.

{
    VOID            *ReturnedBuffer = NULL;

    UDFPrint(("UDFGetCallersBuffer: \n"));

    // If an MDL is supplied, use it.
    if(Irp->MdlAddress) {
        MmPrint(("    UDFGetCallersBuffer: MmGetSystemAddressForMdl(Irp->MdlAddress) MDL=%x\n", Irp->MdlAddress));
//        ReturnedBuffer = MmGetSystemAddressForMdlSafe(Irp->MdlAddress, NormalPagePriority);
        ReturnedBuffer = MmGetSystemAddressForMdlSafer(Irp->MdlAddress);
    } else
    if (PtrIrpContext->IrpContextFlags & UDF_IRP_CONTEXT_BUFFER_LOCKED) {
        // Free buffer
#ifndef POST_LOCK_PAGES
        MmPrint(("    UDFGetCallersBuffer: MmGetSystemAddressForMdl(PtrIrpContext->PtrMdl) MDL=%x\n", PtrIrpContext->PtrMdl));
        ReturnedBuffer = MmGetSystemAddressForMdlSafe(PtrIrpContext->PtrMdl, NormalPagePriority);
#else //POST_LOCK_PAGES
            if(PtrIrpContext->TransitionBuffer) {
                MmPrint(("    UDFGetCallersBuffer: TransitionBuffer\n"));
                return PtrIrpContext->TransitionBuffer;
            }

            _SEH2_TRY {
                MmPrint(("    MmProbeAndLockPages()\n"));
                MmProbeAndLockPages(PtrIrpContext->PtrMdl, Irp->RequestorMode,
                                    ((PtrIrpContext->MajorFunction == IRP_MJ_READ) ? IoWriteAccess:IoReadAccess));
#ifdef UDF_DBG
                LockBufferCounter++;
#endif //UDF_DBG
            } _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
                //RC = STATUS_INVALID_USER_BUFFER;
                BrutePoint();
                return NULL;
            } _SEH2_END;

            MmPrint(("    MmGetSystemAddressForMdlSafer()\n"));
        ReturnedBuffer = MmGetSystemAddressForMdlSafer(PtrIrpContext->PtrMdl);
#endif //POST_LOCK_PAGES
    } else {
        MmPrint(("    UDFGetCallersBuffer: Irp->UserBuffer\n"));
        ReturnedBuffer = Irp->UserBuffer;
    }

    return(ReturnedBuffer);
} // end UDFGetCallersBuffer()

Referenced by UDFCommonRead(), UDFCommonWrite(), and UDFGetVolumeBitmap().

UDFLockCallersBuffer()

NTSTATUS UDFLockCallersBuffer	(	PtrUDFIrpContext	PtrIrpContext,
		PIRP	Irp,
		BOOLEAN	IsReadOperation,
		uint32	Length
	)

Definition at line 936 of file read.cpp.

{
    NTSTATUS            RC = STATUS_SUCCESS;
    PMDL                PtrMdl = NULL;

    UDFPrint(("UDFLockCallersBuffer: \n"));

    ASSERT(Irp);
    
    _SEH2_TRY {
        // Is a MDL already present in the IRP
        if (!(Irp->MdlAddress)) {
            // Allocate a MDL
/*
            if(!IsReadOperation) {
                MmPrint(("  Allocate TransitionBuffer\n"));
                PtrIrpContext->TransitionBuffer = (PCHAR)DbgAllocatePool(NonPagedPool, Length);
                if(!PtrIrpContext->TransitionBuffer) {
                    RC = STATUS_INSUFFICIENT_RESOURCES;
                    try_return(RC);
                }
                _SEH2_TRY {
                    RtlCopyMemory(PtrIrpContext->TransitionBuffer, Irp->UserBuffer, Length);
                } _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
                    RC = STATUS_INVALID_USER_BUFFER;
                } _SEH2_END;
            } else*/ {

                MmPrint(("  IoAllocateMdl()\n"));
//                if (!(PtrMdl = IoAllocateMdl(Irp->UserBuffer, Length, FALSE, FALSE, NULL))) {

                // This will place allocated Mdl to Irp
                if (!(PtrMdl = IoAllocateMdl(Irp->UserBuffer, Length, FALSE, FALSE, Irp))) {
                    RC = STATUS_INSUFFICIENT_RESOURCES;
                    try_return(RC);
                }
                MmPrint(("    Alloc MDL=%x\n", PtrMdl));
#ifdef UDF_DBG
                BuildMdlCounter++;
#endif //UDF_DBG
            }
            // Probe and lock the pages described by the MDL
            // We could encounter an exception doing so, swallow the exception
            // NOTE: The exception could be due to an unexpected (from our
            // perspective), invalidation of the virtual addresses that comprise
            // the passed in buffer
#ifndef POST_LOCK_PAGES
            _SEH2_TRY {
                MmPrint(("    MmProbeAndLockPages()\n"));
                MmProbeAndLockPages(PtrMdl, Irp->RequestorMode, (IsReadOperation ? IoWriteAccess:IoReadAccess));
            } _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
                MmPrint(("    MmProbeAndLockPages() failed\n"));
                Irp->MdlAddress = NULL;
                RC = STATUS_INVALID_USER_BUFFER;
            } _SEH2_END;
#endif //POST_LOCK_PAGES

            if(NT_SUCCESS(RC)) {
                PtrIrpContext->IrpContextFlags |= UDF_IRP_CONTEXT_BUFFER_LOCKED;
                PtrIrpContext->PtrMdl = PtrMdl;
            }
        } else {
            MmPrint(("    UDFLockCallersBuffer: do nothing, MDL=%x\n", Irp->MdlAddress));
            UDFTouch(Irp->MdlAddress);
        }

try_exit:   NOTHING;

    } _SEH2_FINALLY {
        if (!NT_SUCCESS(RC) && PtrMdl) {
            MmPrint(("    Free MDL=%x\n", PtrMdl));
            IoFreeMdl(PtrMdl);
        }
    } _SEH2_END;

    return(RC);
} // end UDFLockCallersBuffer()

Referenced by UDFCommonRead(), UDFCommonWrite(), and UDFQueryDirectory().

UDFMdlComplete()

VOID UDFMdlComplete	(	PtrUDFIrpContext	PtrIrpContext,
		PIRP	Irp,
		PIO_STACK_LOCATION	IrpSp,
		BOOLEAN	ReadCompletion
	)

Definition at line 1117 of file read.cpp.

{
    NTSTATUS                RC = STATUS_SUCCESS;
    PFILE_OBJECT            FileObject = NULL;

    UDFPrint(("UDFMdlComplete: \n"));

    FileObject = IrpSp->FileObject;
    ASSERT(FileObject);

    UDFTouch(Irp->MdlAddress);
    // Not much to do here.
    if (ReadCompletion) {
        MmPrint(("    CcMdlReadComplete() MDL=%x\n", Irp->MdlAddress));
        CcMdlReadComplete(FileObject, Irp->MdlAddress);
    } else {
        // The Cache Manager needs the byte offset in the I/O stack location.
        MmPrint(("    CcMdlWriteComplete() MDL=%x\n", Irp->MdlAddress));
        CcMdlWriteComplete(FileObject, &(IrpSp->Parameters.Write.ByteOffset), Irp->MdlAddress);
    }

    // Clear the MDL address field in the IRP so the IoCompleteRequest()
    // does not __try to play around with the MDL.
    Irp->MdlAddress = NULL;

    // Free up the Irp Context.
    UDFReleaseIrpContext(PtrIrpContext);

    // Complete the IRP.
    Irp->IoStatus.Status = RC;
    Irp->IoStatus.Information = 0;
    IoCompleteRequest(Irp, IO_NO_INCREMENT);

    return;
}

Referenced by UDFCommonRead(), and UDFCommonWrite().

UDFPostStackOverflowRead()

NTSTATUS UDFPostStackOverflowRead	(	IN PtrUDFIrpContext	PtrIrpContext,
		IN PIRP	Irp,
		IN PtrUDFFCB	Fcb
	)

Definition at line 118 of file read.cpp.

{
    PKEVENT Event;
    PERESOURCE Resource;

    UDFPrint(("Getting too close to stack limit pass request to Fsp\n"));

    //  Allocate an event and get shared on the resource we will
    //  be later using the common read.
    Event = (PKEVENT)MyAllocatePool__(NonPagedPool, sizeof(KEVENT));
    if(!Event)
        return STATUS_INSUFFICIENT_RESOURCES;
    KeInitializeEvent( Event, NotificationEvent, FALSE );

    if ((Irp->Flags & IRP_PAGING_IO) && (Fcb->NTRequiredFCB->CommonFCBHeader.PagingIoResource)) {
        Resource = Fcb->NTRequiredFCB->CommonFCBHeader.PagingIoResource;
    } else {
        Resource = Fcb->NTRequiredFCB->CommonFCBHeader.Resource;
    }

    UDFAcquireResourceShared( Resource, TRUE );

    _SEH2_TRY {
        //  If this read is the result of a verify, we have to
        //  tell the overflow read routne to temporarily
        //  hijack the Vcb->VerifyThread field so that reads
        //  can go through.
        FsRtlPostStackOverflow(PtrIrpContext, Event, UDFStackOverflowRead);
        //  And wait for the worker thread to complete the item
        DbgWaitForSingleObject(Event, NULL);

    } _SEH2_FINALLY {

        UDFReleaseResource( Resource );
        MyFreePool__( Event );
    } _SEH2_END;

    return STATUS_PENDING;

} // end UDFPostStackOverflowRead()

Referenced by UDFCommonRead().

UDFRead()

NTSTATUS NTAPI UDFRead	(	PDEVICE_OBJECT	DeviceObject,
		PIRP	Irp
	)

Definition at line 53 of file read.cpp.

{
    NTSTATUS            RC = STATUS_SUCCESS;
    PtrUDFIrpContext    PtrIrpContext = NULL;
    BOOLEAN             AreWeTopLevel = FALSE;

    TmPrint(("UDFRead: \n"));

    FsRtlEnterFileSystem();
    ASSERT(DeviceObject);
    ASSERT(Irp);

    // set the top level context
    AreWeTopLevel = UDFIsIrpTopLevel(Irp);
    ASSERT(!UDFIsFSDevObj(DeviceObject));

    _SEH2_TRY {

        // get an IRP context structure and issue the request
        PtrIrpContext = UDFAllocateIrpContext(Irp, DeviceObject);
        if(PtrIrpContext) {
            RC = UDFCommonRead(PtrIrpContext, Irp);
        } else {
            RC = STATUS_INSUFFICIENT_RESOURCES;
            Irp->IoStatus.Status = RC;
            Irp->IoStatus.Information = 0;
            // complete the IRP
            IoCompleteRequest(Irp, IO_DISK_INCREMENT);
        }

    } _SEH2_EXCEPT(UDFExceptionFilter(PtrIrpContext, _SEH2_GetExceptionInformation())) {

        RC = UDFExceptionHandler(PtrIrpContext, Irp);

        UDFLogEvent(UDF_ERROR_INTERNAL_ERROR, RC);
    } _SEH2_END;

    if (AreWeTopLevel) {
        IoSetTopLevelIrp(NULL);
    }

    FsRtlExitFileSystem();

    return(RC);
} // end UDFRead()

Referenced by UDFInitializeFunctionPointers().

UDFStackOverflowRead()

VOID NTAPI UDFStackOverflowRead	(	IN PVOID	Context,
		IN PKEVENT	Event
	)

Definition at line 185 of file read.cpp.

{
    PtrUDFIrpContext PtrIrpContext = (PtrUDFIrpContext)Context;
    NTSTATUS RC;

    UDFPrint(("UDFStackOverflowRead: \n"));
    //  Make it now look like we can wait for I/O to complete
    PtrIrpContext->IrpContextFlags |= UDF_IRP_CONTEXT_CAN_BLOCK;

    //  Do the read operation protected by a try-except clause
    _SEH2_TRY {
        UDFCommonRead(PtrIrpContext, PtrIrpContext->Irp);
    } _SEH2_EXCEPT(UDFExceptionFilter(PtrIrpContext, _SEH2_GetExceptionInformation())) {
        RC = UDFExceptionHandler(PtrIrpContext, PtrIrpContext->Irp);
        UDFLogEvent(UDF_ERROR_INTERNAL_ERROR, RC);
    } _SEH2_END;

    //  Set the stack overflow item's event to tell the original
    //  thread that we're done.
    KeSetEvent( Event, 0, FALSE );
} // end UDFStackOverflowRead()

Referenced by UDFPostStackOverflowRead().

UDFUnlockCallersBuffer()

NTSTATUS UDFUnlockCallersBuffer	(	PtrUDFIrpContext	PtrIrpContext,
		PIRP	Irp,
		PVOID	SystemBuffer
	)

Definition at line 1034 of file read.cpp.

{
    NTSTATUS            RC = STATUS_SUCCESS;

    UDFPrint(("UDFUnlockCallersBuffer: \n"));

    ASSERT(Irp);

    _SEH2_TRY {
        // Is a nonPaged buffer already present in the IRP
        if (PtrIrpContext->IrpContextFlags & UDF_IRP_CONTEXT_BUFFER_LOCKED) {

            UDFPrint(("  UDF_IRP_CONTEXT_BUFFER_LOCKED MDL=%x, Irp MDL=%x\n", PtrIrpContext->PtrMdl, Irp->MdlAddress));
            if(PtrIrpContext->TransitionBuffer) {
                MmPrint(("    UDFUnlockCallersBuffer: free TransitionBuffer\n"));
                DbgFreePool(PtrIrpContext->TransitionBuffer);
                PtrIrpContext->TransitionBuffer = NULL;
                PtrIrpContext->IrpContextFlags &= ~UDF_IRP_CONTEXT_BUFFER_LOCKED;
                try_return(RC);
            }
            // Free buffer
            KeFlushIoBuffers( PtrIrpContext->PtrMdl, TRUE, FALSE );
//            MmPrint(("    IrpCtx->Mdl, MmUnmapLockedPages()\n"));
//            MmUnmapLockedPages(SystemBuffer, PtrIrpContext->PtrMdl);

            // This will be done in IoCompleteIrp !!!

            //MmPrint(("    MmUnlockPages()\n"));
            //MmUnlockPages(PtrIrpContext->PtrMdl);

#ifdef UDF_DBG
            LockBufferCounter--;
#endif //UDF_DBG

            // This will be done in IoCompleteIrp !!!

            //IoFreeMdl(PtrIrpContext->PtrMdl);

#ifdef UDF_DBG
            BuildMdlCounter--;
#endif //UDF_DBG
            UDFTouch(PtrIrpContext->PtrMdl);
            PtrIrpContext->PtrMdl = NULL;
            PtrIrpContext->IrpContextFlags &= ~UDF_IRP_CONTEXT_BUFFER_LOCKED;
        } else
        if(Irp->MdlAddress) {
//            MmPrint(("    Irp->Mdl, MmUnmapLockedPages()\n"));
//            MmUnmapLockedPages(SystemBuffer, Irp->MdlAddress);
            UDFPrint(("  UDF_IRP_CONTEXT_BUFFER_LOCKED MDL=%x, Irp MDL=%x\n", PtrIrpContext->PtrMdl, Irp->MdlAddress));
            UDFTouch(Irp->MdlAddress);
            KeFlushIoBuffers( Irp->MdlAddress,
                              ((IoGetCurrentIrpStackLocation(Irp))->MajorFunction) == IRP_MJ_READ,
                              FALSE );
        } else
        { ; }

try_exit:   NOTHING;

    } _SEH2_FINALLY {
        NOTHING;
    } _SEH2_END;

    return(RC);
} // end UDFUnlockCallersBuffer()

Referenced by UDFCommonRead(), UDFCommonWrite(), and UDFGetVolumeBitmap().