Leaked source code of windows server 2003
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/*++
Copyright (c) 1990 Microsoft Corporation
Module Name:
LbcbSup.c
Abstract:
This module provides support for manipulating log buffer control blocks.
Author:
Brian Andrew [BrianAn] 20-June-1991
Revision History:
--*/
#include "lfsprocs.h"
//
// The debug trace level
//
#define Dbg (DEBUG_TRACE_LBCB_SUP)
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, LfsFlushToLsnPriv)
#pragma alloc_text(PAGE, LfsGetLbcb)
#endif
extern LARGE_INTEGER LiMinus1;
VOID
LfsFlushToLsnPriv (
IN PLFCB Lfcb,
IN LSN Lsn,
IN BOOLEAN RestartLsn
)
/*++
Routine Description:
This routine is the worker routine which performs the work of flushing
a particular Lsn to disk. This routine is always called with the
Lfcb acquired. This routines makes no guarantee about whether the Lfcb
is acquired on exit.
Arguments:
Lfcb - This is the file control block for the log file.
Lsn - This is the Lsn to flush to disk.
RestartLsn - whether this lsn is a lfs restart lsn
Return Value:
None.
--*/
{
LSN FlushedLsn;
volatile LARGE_INTEGER StartTime;
LFS_WAITER LfsWaiter;
BOOLEAN OwnedExclusive;
BOOLEAN Flush;
PAGED_CODE();
DebugTrace( +1, Dbg, "LfsFlushLbcb: Entered\n", 0 );
DebugTrace( 0, Dbg, "Lfcb -> %08lx\n", Lfcb );
DebugTrace( 0, Dbg, "Lbcb -> %08lx\n", Lbcb );
KeQueryTickCount( &StartTime );
//
// Convert max lsn to the current lsn which will not change since we hold the
// lfcb at least shared at this point and writers need it exclusive
// We do not care if the log progresses beyond this point
//
if (!RestartLsn && (Lsn.QuadPart > Lfcb->RestartArea->CurrentLsn.QuadPart)) {
Lsn = Lfcb->RestartArea->CurrentLsn;
}
//
// Init a wait entry - this is a lightweight operation
//
KeInitializeEvent( &LfsWaiter.Event, SynchronizationEvent, FALSE );
LfsWaiter.Lsn.QuadPart = Lsn.QuadPart;
//
// We loop here until the desired Lsn has made it to disk.
// If we are able to do the I/O, we will perform it.
//
OwnedExclusive = ExIsResourceAcquiredExclusiveLite( &Lfcb->Sync->Resource );
while (TRUE) {
Flush = FALSE;
ExAcquireFastMutexUnsafe( &Lfcb->Sync->Mutex );
if (RestartLsn) {
FlushedLsn = Lfcb->LastFlushedRestartLsn;
} else {
FlushedLsn = Lfcb->LastFlushedLsn;
}
//
// Check if we still need to flush or can immediately return
//
if (Lsn.QuadPart <= FlushedLsn.QuadPart) {
ExReleaseFastMutexUnsafe( &Lfcb->Sync->Mutex );
break;
}
if (Lfcb->Sync->LfsIoState == LfsNoIoInProgress) {
Lfcb->Sync->LfsIoState = LfsClientThreadIo;
Lfcb->LfsIoThread = ExGetCurrentResourceThread();
Flush = TRUE;
} else {
PLFS_WAITER TempWaiter = (PLFS_WAITER)Lfcb->WaiterList.Flink;
//
// Insert the wait entry in the sorted list of waiters -
// find its place first
//
while ((PVOID)TempWaiter != &Lfcb->WaiterList) {
if (TempWaiter->Lsn.QuadPart > Lsn.QuadPart) {
break;
}
TempWaiter = (PLFS_WAITER)TempWaiter->Waiters.Flink;
}
InsertTailList( &TempWaiter->Waiters, &LfsWaiter.Waiters );
}
ExReleaseFastMutexUnsafe( &Lfcb->Sync->Mutex );
//
//
// If we can do the Io, call down to flush the Lfcb.
//
if (Flush) {
LfsFlushLfcb( Lfcb, Lsn, RestartLsn );
break;
}
//
// Otherwise we release the Lfcb and immediately wait on the event.
//
InterlockedIncrement( &Lfcb->Waiters );
LfsReleaseLfcb( Lfcb );
KeWaitForSingleObject( &LfsWaiter.Event,
Executive,
KernelMode,
FALSE,
NULL );
if (OwnedExclusive) {
LfsAcquireLfcbExclusive( Lfcb );
} else {
LfsAcquireLfcbShared( Lfcb );
}
InterlockedDecrement( &Lfcb->Waiters );
}
DebugTrace( -1, Dbg, "LfsFlushToLsnPriv: Exit\n", 0 );
return;
}
PLBCB
LfsGetLbcb (
IN PLFCB Lfcb
)
/*++
Routine Description:
This routine is called to add a Lbcb to the active queue.
Arguments:
Lfcb - This is the file control block for the log file.
Return Value:
PLBCB - Pointer to the Lbcb allocated.
--*/
{
PLBCB Lbcb = NULL;
PVOID PageHeader;
PBCB PageHeaderBcb = NULL;
BOOLEAN WrappedOrUsaError;
PAGED_CODE();
DebugTrace( +1, Dbg, "LfsGetLbcb: Entered\n", 0 );
DebugTrace( 0, Dbg, "Lfcb -> %08lx\n", Lfcb );
//
// Use a try-finally to facilitate cleanup.
//
try {
//
// Pin the desired record page.
//
LfsPreparePinWriteData( Lfcb,
Lfcb->NextLogPage,
(ULONG)Lfcb->LogPageSize,
FlagOn( Lfcb->Flags, LFCB_REUSE_TAIL ),
&PageHeader,
&PageHeaderBcb );
#ifdef LFS_CLUSTER_CHECK
//
// Check the page to see if there is already data on this page with the current sequence
// number. Useful to track cases where ntfs didn't find the correct end of the log or
// where the cluster service has the volume mounted twice.
//
if (LfsTestCheckLbcb &&
*((PULONG) PageHeader) == LFS_SIGNATURE_RECORD_PAGE_ULONG) {
LSN LastLsn = ((PLFS_RECORD_PAGE_HEADER) PageHeader)->Copy.LastLsn;
//
// This is not an exhaustive test but should be sufficient to catch the typical case.
//
ASSERT( FlagOn( Lfcb->Flags, LFCB_NO_LAST_LSN | LFCB_REUSE_TAIL ) ||
(LfsLsnToSeqNumber( Lfcb, LastLsn ) < (ULONGLONG) Lfcb->SeqNumber) ||
(Lfcb->NextLogPage == Lfcb->FirstLogPage) );
}
#endif
//
// Put our signature into the page so we won't fail if we
// see a previous 'BAAD' signature.
//
*((PULONG) PageHeader) = LFS_SIGNATURE_RECORD_PAGE_ULONG;
//
// Now allocate an Lbcb.
//
LfsAllocateLbcb( Lfcb, &Lbcb );
//
// If we are at the beginning of the file we test that the
// sequence number won't wrap to 0.
//
if (!FlagOn( Lfcb->Flags, LFCB_NO_LAST_LSN | LFCB_REUSE_TAIL )
&& ( Lfcb->NextLogPage == Lfcb->FirstLogPage )) {
Lfcb->SeqNumber = Lfcb->SeqNumber + 1;
//
// If the sequence number is going from 0 to 1, then
// this is the first time the log file has wrapped. We want
// to remember this because it means that we can now do
// large spiral writes.
//
if (Int64ShllMod32( Lfcb->SeqNumber, Lfcb->FileDataBits ) == 0) {
DebugTrace( 0, Dbg, "Log sequence number about to wrap: Lfcb -> %08lx\n", Lfcb );
KeBugCheckEx( FILE_SYSTEM, 4, 0, 0, 0 );
}
//
// If this number is greater or equal to the wrap sequence number in
// the Lfcb, set the wrap flag in the Lbcb.
//
if (!FlagOn( Lfcb->Flags, LFCB_LOG_WRAPPED )
&& ( Lfcb->SeqNumber >= Lfcb->SeqNumberForWrap )) {
SetFlag( Lbcb->LbcbFlags, LBCB_LOG_WRAPPED );
SetFlag( Lfcb->Flags, LFCB_LOG_WRAPPED );
}
}
//
// Now initialize the rest of the Lbcb fields.
//
Lbcb->FileOffset = Lfcb->NextLogPage;
Lbcb->SeqNumber = Lfcb->SeqNumber;
Lbcb->BufferOffset = Lfcb->LogPageDataOffset;
//
// Store the next page in the Lfcb.
//
LfsNextLogPageOffset( Lfcb,
Lfcb->NextLogPage,
&Lfcb->NextLogPage,
&WrappedOrUsaError );
Lbcb->Length = Lfcb->LogPageSize;
Lbcb->PageHeader = PageHeader;
Lbcb->LogPageBcb = PageHeaderBcb;
Lbcb->ResourceThread = ExGetCurrentResourceThread();
Lbcb->ResourceThread = (ERESOURCE_THREAD) ((ULONG) Lbcb->ResourceThread | 3);
//
// If we are reusing a previous page then set a flag in
// the Lbcb to indicate that we should flush a copy
// first.
//
if (FlagOn( Lfcb->Flags, LFCB_REUSE_TAIL )) {
SetFlag( Lbcb->LbcbFlags, LBCB_FLUSH_COPY );
ClearFlag( Lfcb->Flags, LFCB_REUSE_TAIL );
(ULONG)Lbcb->BufferOffset = Lfcb->ReusePageOffset;
Lbcb->Flags = ((PLFS_RECORD_PAGE_HEADER) PageHeader)->Flags;
Lbcb->LastLsn = ((PLFS_RECORD_PAGE_HEADER) PageHeader)->Copy.LastLsn;
Lbcb->LastEndLsn = ((PLFS_RECORD_PAGE_HEADER) PageHeader)->Header.Packed.LastEndLsn;
}
//
// Put the Lbcb on the active queue
//
InsertTailList( &Lfcb->LbcbActive, &Lbcb->ActiveLinks );
SetFlag( Lbcb->LbcbFlags, LBCB_ON_ACTIVE_QUEUE );
//
// Now that we have succeeded, set the owner thread to Thread + 1 so the resource
// package will know not to peek in this thread. It may be deallocated before
// we release the Bcb during flush.
//
CcSetBcbOwnerPointer( Lbcb->LogPageBcb, (PVOID) Lbcb->ResourceThread );
} finally {
DebugUnwind( LfsGetLbcb );
//
// If an error occurred, we need to clean up any blocks which
// have not been added to the active queue.
//
if (AbnormalTermination()) {
if (Lbcb != NULL) {
LfsDeallocateLbcb( Lfcb, Lbcb );
Lbcb = NULL;
}
//
// Unpin the system page if pinned.
//
if (PageHeaderBcb != NULL) {
CcUnpinData( PageHeaderBcb );
}
}
DebugTrace( -1, Dbg, "LfsGetLbcb: Exit\n", 0 );
}
return Lbcb;
}