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1062 lines
34 KiB
1062 lines
34 KiB
/*++
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Copyright (c) 1989 Microsoft Corporation
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Module Name:
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FastIo2.c
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Abstract:
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This module REimplements the fsrtl copy read/write routines.
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Author:
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Joe Linn [JoeLinn] 9-Nov-1994
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Revision History:
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--*/
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#include "precomp.h"
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#pragma hdrstop
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#ifndef FlagOn
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//
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// This macro returns TRUE if a flag in a set of flags is on and FALSE
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// otherwise
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//
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#define FlagOn(Flags,SingleFlag) ((Flags) & (SingleFlag))
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#endif
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BOOLEAN
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FsRtlCopyRead2 (
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IN PFILE_OBJECT FileObject,
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IN PLARGE_INTEGER FileOffset,
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IN ULONG Length,
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IN BOOLEAN Wait,
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IN ULONG LockKey,
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OUT PVOID Buffer,
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OUT PIO_STATUS_BLOCK IoStatus,
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IN PDEVICE_OBJECT DeviceObject,
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IN ULONG_PTR TopLevelIrpValue
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);
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BOOLEAN
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FsRtlCopyWrite2 (
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IN PFILE_OBJECT FileObject,
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IN PLARGE_INTEGER FileOffset,
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IN ULONG Length,
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IN BOOLEAN Wait,
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IN ULONG LockKey,
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IN PVOID Buffer,
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OUT PIO_STATUS_BLOCK IoStatus,
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IN PDEVICE_OBJECT DeviceObject,
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IN ULONG_PTR TopLevelIrpValue
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);
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(PAGE, FsRtlCopyRead2)
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#pragma alloc_text(PAGE, FsRtlCopyWrite2)
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#endif
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BOOLEAN
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FsRtlCopyRead2 (
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IN PFILE_OBJECT FileObject,
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IN PLARGE_INTEGER FileOffset,
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IN ULONG Length,
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IN BOOLEAN Wait,
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IN ULONG LockKey,
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OUT PVOID Buffer,
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OUT PIO_STATUS_BLOCK IoStatus,
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IN PDEVICE_OBJECT DeviceObject,
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IN ULONG_PTR TopLevelIrpValue
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)
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/*++
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Routine Description:
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This routine does a fast cached read bypassing the usual file system
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entry routine (i.e., without the Irp). It is used to do a copy read
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of a cached file object. For a complete description of the arguments
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see CcCopyRead.
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Arguments:
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FileObject - Pointer to the file object being read.
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FileOffset - Byte offset in file for desired data.
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Length - Length of desired data in bytes.
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Wait - FALSE if caller may not block, TRUE otherwise
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Buffer - Pointer to output buffer to which data should be copied.
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IoStatus - Pointer to standard I/O status block to receive the status
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for the transfer.
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Return Value:
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FALSE - if Wait was supplied as FALSE and the data was not delivered, or
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if there is an I/O error.
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TRUE - if the data is being delivered
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--*/
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{
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PFSRTL_COMMON_FCB_HEADER Header;
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BOOLEAN Status = TRUE;
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ULONG PageCount = ADDRESS_AND_SIZE_TO_SPAN_PAGES((ULongToPtr(FileOffset->LowPart)), Length);
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LARGE_INTEGER BeyondLastByte;
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PDEVICE_OBJECT targetVdo;
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PAGED_CODE();
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//
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// Special case a read of zero length
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//
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if (Length != 0) {
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//
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// Get a real pointer to the common fcb header
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//
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BeyondLastByte.QuadPart = FileOffset->QuadPart + (LONGLONG)Length;
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Header = (PFSRTL_COMMON_FCB_HEADER)FileObject->FsContext;
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//
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// Enter the file system
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//
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FsRtlEnterFileSystem();
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//
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// Increment performance counters and get the resource
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//
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if (Wait) {
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//
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// Acquired shared on the common fcb header
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//
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(VOID)ExAcquireResourceSharedLite( Header->Resource, TRUE );
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} else {
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//
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// Acquired shared on the common fcb header, and return if we
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// don't get it
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//
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if (!ExAcquireResourceSharedLite( Header->Resource, FALSE )) {
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FsRtlExitFileSystem();
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//the ntfs guys dont do this AND it causes a compile error for me so
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//comment it out
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//CcFastReadResourceMiss += 1;
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return FALSE;
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}
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}
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//
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// Now that the File is acquired shared, we can safely test if it
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// is really cached and if we can do fast i/o and if not, then
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// release the fcb and return.
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//
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if ((FileObject->PrivateCacheMap == NULL) ||
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(Header->IsFastIoPossible == FastIoIsNotPossible)) {
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ExReleaseResourceLite( Header->Resource );
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FsRtlExitFileSystem();
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return FALSE;
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}
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//
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// Check if fast I/O is questionable and if so then go ask the
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// file system the answer
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//
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if (Header->IsFastIoPossible == FastIoIsQuestionable) {
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PFAST_IO_DISPATCH FastIoDispatch;
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ASSERT(!KeIsExecutingDpc());
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targetVdo = IoGetRelatedDeviceObject( FileObject );
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FastIoDispatch = targetVdo->DriverObject->FastIoDispatch;
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//
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// All file systems that set "Is Questionable" had better support
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// fast I/O
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//
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ASSERT(FastIoDispatch != NULL);
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ASSERT(FastIoDispatch->FastIoCheckIfPossible != NULL);
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//
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// Call the file system to check for fast I/O. If the answer is
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// anything other than GoForIt then we cannot take the fast I/O
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// path.
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//
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if (!FastIoDispatch->FastIoCheckIfPossible( FileObject,
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FileOffset,
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Length,
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Wait,
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LockKey,
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TRUE, // read operation
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IoStatus,
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targetVdo )) {
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//
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// Fast I/O is not possible so release the Fcb and return.
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//
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ExReleaseResourceLite( Header->Resource );
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FsRtlExitFileSystem();
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return FALSE;
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}
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}
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//
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// Check for read past file size.
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//
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if ( BeyondLastByte.QuadPart > Header->FileSize.QuadPart ) {
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if ( FileOffset->QuadPart >= Header->FileSize.QuadPart ) {
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IoStatus->Status = STATUS_END_OF_FILE;
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IoStatus->Information = 0;
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ExReleaseResourceLite( Header->Resource );
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FsRtlExitFileSystem();
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return TRUE;
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}
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Length = (ULONG)( Header->FileSize.QuadPart - FileOffset->QuadPart );
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}
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//
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// We can do fast i/o so call the cc routine to do the work and then
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// release the fcb when we've done. If for whatever reason the
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// copy read fails, then return FALSE to our caller.
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//
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// Also mark this as the top level "Irp" so that lower file system
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// levels will not attempt a pop-up
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//
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//PsGetCurrentThread()->TopLevelIrp = FSRTL_FAST_IO_TOP_LEVEL_IRP;
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PsGetCurrentThread()->TopLevelIrp = TopLevelIrpValue;
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try {
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if (Wait && ((BeyondLastByte.HighPart | Header->FileSize.HighPart) == 0)) {
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CcFastCopyRead( FileObject,
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FileOffset->LowPart,
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Length,
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PageCount,
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Buffer,
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IoStatus );
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FileObject->Flags |= FO_FILE_FAST_IO_READ;
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ASSERT( (IoStatus->Status == STATUS_END_OF_FILE) ||
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((FileOffset->LowPart + IoStatus->Information) <= Header->FileSize.LowPart));
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} else {
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Status = CcCopyRead( FileObject,
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FileOffset,
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Length,
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Wait,
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Buffer,
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IoStatus );
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FileObject->Flags |= FO_FILE_FAST_IO_READ;
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ASSERT( !Status || (IoStatus->Status == STATUS_END_OF_FILE) ||
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(((ULONGLONG)FileOffset->QuadPart + IoStatus->Information) <= (ULONGLONG)Header->FileSize.QuadPart));
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}
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if (Status) {
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FileObject->CurrentByteOffset.QuadPart = FileOffset->QuadPart + IoStatus->Information;
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}
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} except( FsRtlIsNtstatusExpected(GetExceptionCode())
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? EXCEPTION_EXECUTE_HANDLER
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: EXCEPTION_CONTINUE_SEARCH ) {
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Status = FALSE;
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}
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PsGetCurrentThread()->TopLevelIrp = 0;
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ExReleaseResourceLite( Header->Resource );
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FsRtlExitFileSystem();
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return Status;
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} else {
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//
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// A zero length transfer was requested.
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//
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IoStatus->Status = STATUS_SUCCESS;
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IoStatus->Information = 0;
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return TRUE;
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}
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}
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BOOLEAN
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FsRtlCopyWrite2 (
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IN PFILE_OBJECT FileObject,
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IN PLARGE_INTEGER FileOffset,
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IN ULONG Length,
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IN BOOLEAN Wait,
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IN ULONG LockKey,
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IN PVOID Buffer,
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OUT PIO_STATUS_BLOCK IoStatus,
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IN PDEVICE_OBJECT DeviceObject,
|
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IN ULONG_PTR TopLevelIrpValue
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)
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/*++
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Routine Description:
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|
|
This routine does a fast cached write bypassing the usual file system
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entry routine (i.e., without the Irp). It is used to do a copy write
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of a cached file object. For a complete description of the arguments
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see CcCopyWrite.
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Arguments:
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FileObject - Pointer to the file object being write.
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FileOffset - Byte offset in file for desired data.
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Length - Length of desired data in bytes.
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Wait - FALSE if caller may not block, TRUE otherwise
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Buffer - Pointer to output buffer to which data should be copied.
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IoStatus - Pointer to standard I/O status block to receive the status
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for the transfer.
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Return Value:
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FALSE - if Wait was supplied as FALSE and the data was not delivered, or
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if there is an I/O error.
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TRUE - if the data is being delivered
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--*/
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{
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PFSRTL_COMMON_FCB_HEADER Header;
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BOOLEAN AcquiredShared = FALSE;
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BOOLEAN Status = TRUE;
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BOOLEAN FileSizeChanged = FALSE;
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BOOLEAN WriteToEndOfFile = (BOOLEAN)((FileOffset->LowPart == FILE_WRITE_TO_END_OF_FILE) &&
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(FileOffset->HighPart == -1));
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PAGED_CODE();
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//
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// Get a real pointer to the common fcb header
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//
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Header = (PFSRTL_COMMON_FCB_HEADER)FileObject->FsContext;
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//
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// Do we need to verify the volume? If so, we must go to the file
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// system. Also return FALSE if FileObject is write through, the
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// File System must do that.
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//
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if (CcCanIWrite( FileObject, Length, Wait, FALSE ) &&
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!FlagOn(FileObject->Flags, FO_WRITE_THROUGH) &&
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CcCopyWriteWontFlush(FileObject, FileOffset, Length)) {
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//
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// Assume our transfer will work
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//
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IoStatus->Status = STATUS_SUCCESS;
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IoStatus->Information = Length;
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//
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// Special case the zero byte length
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//
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if (Length != 0) {
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//
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// Enter the file system
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//
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FsRtlEnterFileSystem();
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//
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// Split into separate paths for increased performance. First
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// we have the faster path which only supports Wait == TRUE and
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// 32 bits. We will make an unsafe test on whether the fast path
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// is ok, then just return FALSE later if we were wrong. This
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// should virtually never happen.
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//
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// IMPORTANT NOTE: It is very important that any changes mad to
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// this path also be applied to the 64-bit path
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// which is the else of this test!
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//
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if (Wait && (Header->AllocationSize.HighPart == 0)) {
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ULONG Offset, NewFileSize;
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ULONG OldFileSize;
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ULONG OldValidDataLength;
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BOOLEAN Wrapped;
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//
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// Make our best guess on whether we need the file exclusive
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// or shared. Note that we do not check FileOffset->HighPart
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// until below.
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//
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NewFileSize = FileOffset->LowPart + Length;
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if (WriteToEndOfFile || (NewFileSize > Header->ValidDataLength.LowPart)) {
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//
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// Acquired shared on the common fcb header
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//
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ExAcquireResourceExclusiveLite( Header->Resource, TRUE );
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} else {
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//
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// Acquired shared on the common fcb header
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//
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ExAcquireResourceSharedLite( Header->Resource, TRUE );
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AcquiredShared = TRUE;
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}
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//
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// We have the fcb shared now check if we can do fast i/o
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// and if the file space is allocated, and if not then
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// release the fcb and return.
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//
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if (WriteToEndOfFile) {
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Offset = Header->FileSize.LowPart;
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NewFileSize = Header->FileSize.LowPart + Length;
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Wrapped = NewFileSize < Header->FileSize.LowPart;
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} else {
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Offset = FileOffset->LowPart;
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NewFileSize = FileOffset->LowPart + Length;
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Wrapped = (NewFileSize < FileOffset->LowPart) || (FileOffset->HighPart != 0);
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}
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//
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// Now that the File is acquired shared, we can safely test
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// if it is really cached and if we can do fast i/o and we
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// do not have to extend. If not then release the fcb and
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// return.
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//
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// Get out if we have too much to zero. This case is not important
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// for performance, and a file system supporting sparseness may have
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// a way to do this more efficiently.
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//
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if ((FileObject->PrivateCacheMap == NULL) ||
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(Header->IsFastIoPossible == FastIoIsNotPossible) ||
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(NewFileSize > Header->AllocationSize.LowPart) ||
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(Offset >= (Header->ValidDataLength.LowPart + 0x2000)) ||
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(Header->AllocationSize.HighPart != 0) || Wrapped) {
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ExReleaseResourceLite( Header->Resource );
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FsRtlExitFileSystem();
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return FALSE;
|
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}
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|
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//
|
|
// If we will be extending ValidDataLength, we will have to
|
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// get the Fcb exclusive, and make sure that FastIo is still
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// possible. We should only execute this block of code very
|
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// rarely, when the unsafe test for ValidDataLength failed
|
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// above.
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//
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if (AcquiredShared && (NewFileSize > Header->ValidDataLength.LowPart)) {
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ExReleaseResourceLite( Header->Resource );
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ExAcquireResourceExclusiveLite( Header->Resource, TRUE );
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|
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//
|
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// If writing to end of file, we must recalculate new size.
|
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//
|
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|
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if (WriteToEndOfFile) {
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|
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Offset = Header->FileSize.LowPart;
|
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NewFileSize = Header->FileSize.LowPart + Length;
|
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Wrapped = NewFileSize < Header->FileSize.LowPart;
|
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}
|
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|
|
if ((FileObject->PrivateCacheMap == NULL) ||
|
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(Header->IsFastIoPossible == FastIoIsNotPossible) ||
|
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(NewFileSize > Header->AllocationSize.LowPart) ||
|
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(Header->AllocationSize.HighPart != 0) || Wrapped) {
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|
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ExReleaseResourceLite( Header->Resource );
|
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FsRtlExitFileSystem();
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|
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return FALSE;
|
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}
|
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}
|
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|
|
//
|
|
// Check if fast I/O is questionable and if so then go ask
|
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// the file system the answer
|
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//
|
|
|
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if (Header->IsFastIoPossible == FastIoIsQuestionable) {
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|
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PDEVICE_OBJECT targetVdo = IoGetRelatedDeviceObject( FileObject );
|
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PFAST_IO_DISPATCH FastIoDispatch = targetVdo->DriverObject->FastIoDispatch;
|
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IO_STATUS_BLOCK IoStatus;
|
|
|
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//
|
|
// All file system then set "Is Questionable" had better
|
|
// support fast I/O
|
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//
|
|
|
|
ASSERT(FastIoDispatch != NULL);
|
|
ASSERT(FastIoDispatch->FastIoCheckIfPossible != NULL);
|
|
|
|
//
|
|
// Call the file system to check for fast I/O. If the
|
|
// answer is anything other than GoForIt then we cannot
|
|
// take the fast I/O path.
|
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//
|
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|
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ASSERT(FILE_WRITE_TO_END_OF_FILE == 0xffffffff);
|
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|
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if (!FastIoDispatch->FastIoCheckIfPossible( FileObject,
|
|
FileOffset->QuadPart != (LONGLONG)-1 ?
|
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FileOffset : &Header->FileSize,
|
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Length,
|
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TRUE,
|
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LockKey,
|
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FALSE, // write operation
|
|
&IoStatus,
|
|
targetVdo )) {
|
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|
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//
|
|
// Fast I/O is not possible so release the Fcb and
|
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// return.
|
|
//
|
|
|
|
ExReleaseResourceLite( Header->Resource );
|
|
FsRtlExitFileSystem();
|
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|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Now see if we will change FileSize. We have to do it now
|
|
// so that our reads are not nooped.
|
|
//
|
|
|
|
if (NewFileSize > Header->FileSize.LowPart) {
|
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|
|
FileSizeChanged = TRUE;
|
|
OldFileSize = Header->FileSize.LowPart;
|
|
OldValidDataLength = Header->ValidDataLength.LowPart;
|
|
Header->FileSize.LowPart = NewFileSize;
|
|
}
|
|
|
|
//
|
|
// We can do fast i/o so call the cc routine to do the work
|
|
// and then release the fcb when we've done. If for whatever
|
|
// reason the copy write fails, then return FALSE to our
|
|
// caller.
|
|
//
|
|
// Also mark this as the top level "Irp" so that lower file
|
|
// system levels will not attempt a pop-up
|
|
//
|
|
|
|
PsGetCurrentThread()->TopLevelIrp = TopLevelIrpValue;
|
|
|
|
try {
|
|
|
|
//
|
|
// See if we have to do some zeroing
|
|
//
|
|
|
|
if (Offset > Header->ValidDataLength.LowPart) {
|
|
|
|
LARGE_INTEGER ZeroEnd;
|
|
|
|
ZeroEnd.LowPart = Offset;
|
|
ZeroEnd.HighPart = 0;
|
|
|
|
CcZeroData( FileObject,
|
|
&Header->ValidDataLength,
|
|
&ZeroEnd,
|
|
TRUE );
|
|
}
|
|
|
|
CcFastCopyWrite( FileObject,
|
|
Offset,
|
|
Length,
|
|
Buffer );
|
|
|
|
} except( FsRtlIsNtstatusExpected(GetExceptionCode())
|
|
? EXCEPTION_EXECUTE_HANDLER
|
|
: EXCEPTION_CONTINUE_SEARCH ) {
|
|
|
|
Status = FALSE;
|
|
}
|
|
|
|
PsGetCurrentThread()->TopLevelIrp = 0;
|
|
|
|
//
|
|
// If we succeeded, see if we have to update FileSize or
|
|
// ValidDataLength.
|
|
//
|
|
|
|
if (Status) {
|
|
|
|
//
|
|
// In the case of ValidDataLength, we really have to
|
|
// check again since we did not do this when we acquired
|
|
// the resource exclusive.
|
|
//
|
|
|
|
if (NewFileSize > Header->ValidDataLength.LowPart) {
|
|
|
|
Header->ValidDataLength.LowPart = NewFileSize;
|
|
}
|
|
|
|
//
|
|
// Set this handle as having modified the file
|
|
//
|
|
|
|
FileObject->Flags |= FO_FILE_MODIFIED;
|
|
|
|
if (FileSizeChanged) {
|
|
|
|
CcGetFileSizePointer(FileObject)->LowPart = NewFileSize;
|
|
|
|
FileObject->Flags |= FO_FILE_SIZE_CHANGED;
|
|
}
|
|
|
|
//
|
|
// Also update the file position pointer
|
|
//
|
|
|
|
FileObject->CurrentByteOffset.LowPart = Offset + Length;
|
|
FileObject->CurrentByteOffset.HighPart = 0;
|
|
|
|
//
|
|
// If we did not succeed, then we must restore the original
|
|
// FileSize while holding the PagingIoResource exclusive if
|
|
// it exists.
|
|
//
|
|
|
|
} else if (FileSizeChanged) {
|
|
|
|
if ( Header->PagingIoResource != NULL ) {
|
|
|
|
(VOID)ExAcquireResourceExclusiveLite( Header->PagingIoResource, TRUE );
|
|
Header->FileSize.LowPart = OldFileSize;
|
|
Header->ValidDataLength.LowPart = OldValidDataLength;
|
|
ExReleaseResourceLite( Header->PagingIoResource );
|
|
|
|
} else {
|
|
|
|
Header->FileSize.LowPart = OldFileSize;
|
|
Header->ValidDataLength.LowPart = OldValidDataLength;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Here is the 64-bit or no-wait path.
|
|
//
|
|
|
|
} else {
|
|
|
|
LARGE_INTEGER Offset, NewFileSize;
|
|
LARGE_INTEGER OldFileSize;
|
|
LARGE_INTEGER OldValidDataLength;
|
|
|
|
ASSERT(!KeIsExecutingDpc());
|
|
|
|
//
|
|
// Make our best guess on whether we need the file exclusive
|
|
// or shared.
|
|
//
|
|
|
|
NewFileSize.QuadPart = FileOffset->QuadPart + (LONGLONG)Length;
|
|
|
|
if (WriteToEndOfFile || (NewFileSize.QuadPart > Header->ValidDataLength.QuadPart)) {
|
|
|
|
//
|
|
// Acquired shared on the common fcb header, and return
|
|
// if we don't get it.
|
|
//
|
|
|
|
if (!ExAcquireResourceExclusiveLite( Header->Resource, Wait )) {
|
|
|
|
FsRtlExitFileSystem();
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
} else {
|
|
|
|
//
|
|
// Acquired shared on the common fcb header, and return
|
|
// if we don't get it.
|
|
//
|
|
|
|
if (!ExAcquireResourceSharedLite( Header->Resource, Wait )) {
|
|
|
|
FsRtlExitFileSystem();
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
AcquiredShared = TRUE;
|
|
}
|
|
|
|
|
|
//
|
|
// We have the fcb shared now check if we can do fast i/o
|
|
// and if the file space is allocated, and if not then
|
|
// release the fcb and return.
|
|
//
|
|
|
|
if (WriteToEndOfFile) {
|
|
|
|
Offset = Header->FileSize;
|
|
NewFileSize.QuadPart = Header->FileSize.QuadPart + (LONGLONG)Length;
|
|
|
|
} else {
|
|
|
|
Offset = *FileOffset;
|
|
NewFileSize.QuadPart = FileOffset->QuadPart + (LONGLONG)Length;
|
|
}
|
|
|
|
//
|
|
// Now that the File is acquired shared, we can safely test
|
|
// if it is really cached and if we can do fast i/o and we
|
|
// do not have to extend. If not then release the fcb and
|
|
// return.
|
|
//
|
|
// Get out if we are about to zero too much as well, as commented above.
|
|
//
|
|
|
|
if ((FileObject->PrivateCacheMap == NULL) ||
|
|
(Header->IsFastIoPossible == FastIoIsNotPossible) ||
|
|
(Offset.QuadPart >= (Header->ValidDataLength.QuadPart + 0x2000)) ||
|
|
( NewFileSize.QuadPart > Header->AllocationSize.QuadPart ) ) {
|
|
|
|
ExReleaseResourceLite( Header->Resource );
|
|
FsRtlExitFileSystem();
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// If we will be extending ValidDataLength, we will have to
|
|
// get the Fcb exclusive, and make sure that FastIo is still
|
|
// possible. We should only execute this block of code very
|
|
// rarely, when the unsafe test for ValidDataLength failed
|
|
// above.
|
|
//
|
|
|
|
if (AcquiredShared && ( NewFileSize.QuadPart > Header->ValidDataLength.QuadPart )) {
|
|
|
|
ExReleaseResourceLite( Header->Resource );
|
|
|
|
if (!ExAcquireResourceExclusiveLite( Header->Resource, Wait )) {
|
|
|
|
FsRtlExitFileSystem();
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// If writing to end of file, we must recalculate new size.
|
|
//
|
|
|
|
if (WriteToEndOfFile) {
|
|
|
|
Offset = Header->FileSize;
|
|
NewFileSize.QuadPart = Header->FileSize.QuadPart + (LONGLONG)Length;
|
|
}
|
|
|
|
if ((FileObject->PrivateCacheMap == NULL) ||
|
|
(Header->IsFastIoPossible == FastIoIsNotPossible) ||
|
|
( NewFileSize.QuadPart > Header->AllocationSize.QuadPart ) ) {
|
|
|
|
ExReleaseResourceLite( Header->Resource );
|
|
FsRtlExitFileSystem();
|
|
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Check if fast I/O is questionable and if so then go ask
|
|
// the file system the answer
|
|
//
|
|
|
|
if (Header->IsFastIoPossible == FastIoIsQuestionable) {
|
|
|
|
PDEVICE_OBJECT targetVdo = IoGetRelatedDeviceObject( FileObject );
|
|
PFAST_IO_DISPATCH FastIoDispatch = targetVdo->DriverObject->FastIoDispatch;
|
|
IO_STATUS_BLOCK IoStatus;
|
|
|
|
//
|
|
// All file system then set "Is Questionable" had better
|
|
// support fast I/O
|
|
//
|
|
|
|
ASSERT(FastIoDispatch != NULL);
|
|
ASSERT(FastIoDispatch->FastIoCheckIfPossible != NULL);
|
|
|
|
//
|
|
// Call the file system to check for fast I/O. If the
|
|
// answer is anything other than GoForIt then we cannot
|
|
// take the fast I/O path.
|
|
//
|
|
|
|
ASSERT(FILE_WRITE_TO_END_OF_FILE == 0xffffffff);
|
|
|
|
if (!FastIoDispatch->FastIoCheckIfPossible( FileObject,
|
|
FileOffset->QuadPart != (LONGLONG)-1 ?
|
|
FileOffset : &Header->FileSize,
|
|
Length,
|
|
Wait,
|
|
LockKey,
|
|
FALSE, // write operation
|
|
&IoStatus,
|
|
targetVdo )) {
|
|
|
|
//
|
|
// Fast I/O is not possible so release the Fcb and
|
|
// return.
|
|
//
|
|
|
|
ExReleaseResourceLite( Header->Resource );
|
|
FsRtlExitFileSystem();
|
|
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Now see if we will change FileSize. We have to do it now
|
|
// so that our reads are not nooped.
|
|
//
|
|
|
|
if ( NewFileSize.QuadPart > Header->FileSize.QuadPart ) {
|
|
|
|
FileSizeChanged = TRUE;
|
|
OldFileSize = Header->FileSize;
|
|
OldValidDataLength = Header->ValidDataLength;
|
|
|
|
//
|
|
// Deal with an extremely rare pathalogical case here the
|
|
// file size wraps.
|
|
//
|
|
|
|
if ( (Header->FileSize.HighPart != NewFileSize.HighPart) &&
|
|
(Header->PagingIoResource != NULL) ) {
|
|
|
|
(VOID)ExAcquireResourceExclusiveLite( Header->PagingIoResource, TRUE );
|
|
Header->FileSize = NewFileSize;
|
|
ExReleaseResourceLite( Header->PagingIoResource );
|
|
|
|
} else {
|
|
|
|
Header->FileSize = NewFileSize;
|
|
}
|
|
}
|
|
|
|
//
|
|
// We can do fast i/o so call the cc routine to do the work
|
|
// and then release the fcb when we've done. If for whatever
|
|
// reason the copy write fails, then return FALSE to our
|
|
// caller.
|
|
//
|
|
// Also mark this as the top level "Irp" so that lower file
|
|
// system levels will not attempt a pop-up
|
|
//
|
|
|
|
PsGetCurrentThread()->TopLevelIrp = TopLevelIrpValue;
|
|
|
|
try {
|
|
|
|
//
|
|
// See if we have to do some zeroing
|
|
//
|
|
|
|
if ( Offset.QuadPart > Header->ValidDataLength.QuadPart ) {
|
|
|
|
Status = CcZeroData( FileObject,
|
|
&Header->ValidDataLength,
|
|
&Offset,
|
|
Wait );
|
|
}
|
|
|
|
if (Status) {
|
|
|
|
Status = CcCopyWrite( FileObject,
|
|
&Offset,
|
|
Length,
|
|
Wait,
|
|
Buffer );
|
|
}
|
|
|
|
} except( FsRtlIsNtstatusExpected(GetExceptionCode())
|
|
? EXCEPTION_EXECUTE_HANDLER
|
|
: EXCEPTION_CONTINUE_SEARCH ) {
|
|
|
|
Status = FALSE;
|
|
}
|
|
|
|
PsGetCurrentThread()->TopLevelIrp = 0;
|
|
|
|
//
|
|
// If we succeeded, see if we have to update FileSize or
|
|
// ValidDataLength.
|
|
//
|
|
|
|
if (Status) {
|
|
|
|
//
|
|
// In the case of ValidDataLength, we really have to
|
|
// check again since we did not do this when we acquired
|
|
// the resource exclusive.
|
|
//
|
|
|
|
if ( NewFileSize.QuadPart > Header->ValidDataLength.QuadPart ) {
|
|
|
|
//
|
|
// Deal with an extremely rare pathalogical case here
|
|
// the ValidDataLength wraps.
|
|
//
|
|
|
|
if ( (Header->ValidDataLength.HighPart != NewFileSize.HighPart) &&
|
|
(Header->PagingIoResource != NULL) ) {
|
|
|
|
(VOID)ExAcquireResourceExclusiveLite( Header->PagingIoResource, TRUE );
|
|
Header->ValidDataLength = NewFileSize;
|
|
ExReleaseResourceLite( Header->PagingIoResource );
|
|
|
|
} else {
|
|
|
|
Header->ValidDataLength = NewFileSize;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Set this handle as having modified the file
|
|
//
|
|
|
|
FileObject->Flags |= FO_FILE_MODIFIED;
|
|
|
|
if (FileSizeChanged) {
|
|
|
|
*CcGetFileSizePointer(FileObject) = NewFileSize;
|
|
|
|
FileObject->Flags |= FO_FILE_SIZE_CHANGED;
|
|
}
|
|
|
|
//
|
|
// Also update the current file position pointer
|
|
//
|
|
|
|
FileObject->CurrentByteOffset.QuadPart = Offset.QuadPart + Length;
|
|
|
|
//
|
|
// If we did not succeed, then we must restore the original
|
|
// FileSize while holding the PagingIoResource exclusive if
|
|
// it exists.
|
|
//
|
|
|
|
} else if (FileSizeChanged) {
|
|
|
|
if ( Header->PagingIoResource != NULL ) {
|
|
|
|
(VOID)ExAcquireResourceExclusiveLite( Header->PagingIoResource, TRUE );
|
|
Header->FileSize = OldFileSize;
|
|
Header->ValidDataLength = OldValidDataLength;
|
|
ExReleaseResourceLite( Header->PagingIoResource );
|
|
|
|
} else {
|
|
|
|
Header->FileSize = OldFileSize;
|
|
Header->ValidDataLength = OldValidDataLength;
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
ExReleaseResourceLite( Header->Resource );
|
|
FsRtlExitFileSystem();
|
|
|
|
return Status;
|
|
|
|
} else {
|
|
|
|
//
|
|
// A zero length transfer was requested.
|
|
//
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
} else {
|
|
|
|
//
|
|
// The volume must be verified or the file is write through.
|
|
//
|
|
|
|
return FALSE;
|
|
}
|
|
}
|
|
|