/*++
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, LfsFlushLbcb)
#pragma alloc_text(PAGE, LfsFlushToLsnPriv)
#pragma alloc_text(PAGE, LfsGetLbcb)
#endif
VOID
LfsFlushLbcb (
IN PLFCB Lfcb,
IN PLBCB Lbcb
)
/*++
Routine Description:
This routine is called to make sure the data within an Lbcb makes it out
to disk. The Lbcb must either already be in the workque or it must be
a restart Lbcb.
Arguments:
Lfcb - This is the file control block for the log file.
Lbcb - This is the Lbcb to flush.
Return Value:
None.
--*/
{
LSN LastLsn;
PLSN FlushedLsn;
PAGED_CODE();
DebugTrace( +1, Dbg, "LfsFlushLbcb: Entered\n", 0 );
DebugTrace( 0, Dbg, "Lfcb -> %08lx\n", Lfcb );
DebugTrace( 0, Dbg, "Lbcb -> %08lx\n", Lbcb );
LastLsn = Lbcb->LastEndLsn;
//
// If this is a restart area we use the restart counter in the
// Lfcb. Otherwise we can use the LastFlushedLsn value in the
// Lfcb. This way we can determine that the Lbcb that interests
// us has made it out to disk.
//
if (LfsLbcbIsRestart( Lbcb )) {
FlushedLsn = &Lfcb->LastFlushedRestartLsn;
} else {
FlushedLsn = &Lfcb->LastFlushedLsn;
}
//
// 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.
//
do {
//
//
// If we can do the Io, call down to flush the Lfcb.
//
if (Lfcb->LfsIoState == LfsNoIoInProgress) {
LfsFlushLfcb( Lfcb, Lbcb );
break;
}
//
// Otherwise we release the Lfcb and immediately wait on the event.
//
LfsReleaseLfcb( Lfcb );
KeWaitForSingleObject( &Lfcb->Sync->Event,
Executive,
KernelMode,
FALSE,
NULL );
LfsAcquireLfcb( Lfcb );
} while ( LastLsn.QuadPart > FlushedLsn->QuadPart );
DebugTrace( -1, Dbg, "LfsFlushLbcb: Exit\n", 0 );
return;
}
VOID
LfsFlushToLsnPriv (
IN PLFCB Lfcb,
IN LSN Lsn
)
/*++
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.
Return Value:
None.
--*/
{
PAGED_CODE();
DebugTrace( +1, Dbg, "LfsFlushToLsnPriv: Entered\n", 0 );
DebugTrace( 0, Dbg, "Lfcb -> %08lx\n", Lfcb );
DebugTrace( 0, Dbg, "Lsn (Low) -> %08lx\n", Lsn.LowPart );
DebugTrace( 0, Dbg, "Lsn (High) -> %08lx\n", Lsn.HighPart );
//
// We check if the Lsn is in the valid range. Raising an
// exception if not.
//
if ( Lsn.QuadPart > Lfcb->RestartArea->CurrentLsn.QuadPart ) {
DebugTrace( 0, Dbg, "Lsn is not in the file\n", 0 );
ExRaiseStatus( STATUS_INVALID_PARAMETER );
}
//
// If the Lsn has already been flushed we are done.
// Otherwise we need to look through the workqueues and the
// active queue.
//
if ( Lsn.QuadPart > Lfcb->LastFlushedLsn.QuadPart ) {
PLIST_ENTRY ThisEntry;
PLBCB ThisLbcb;
//
// Check the workqueue first. We are looking for the last
// buffer block of a log page block which contains this
// Lsn.
//
ThisEntry = Lfcb->LbcbWorkque.Flink;
//
// We keep looping.
//
while (TRUE) {
ThisLbcb = CONTAINING_RECORD( ThisEntry,
LBCB,
WorkqueLinks );
//
// We pass over any restart areas. We also skip any
// Lbcb's which do not contain the end of a log record.
//
if (!LfsLbcbIsRestart( ThisLbcb )
&& FlagOn( ThisLbcb->Flags, LOG_PAGE_LOG_RECORD_END )) {
//
// If the last complete Lsn in this Lbcb is greater or equal
// to the desired Lsn, we exit the loop.
//
if ( ThisLbcb->LastEndLsn.QuadPart >= Lsn.QuadPart ) {
break;
}
}
//
// Otherwise move to the next Lbcb.
//
ThisEntry = ThisEntry->Flink;
ASSERT( ThisEntry != &Lfcb->LbcbWorkque );
}
//
// If we are not supporting a packed log file and this Lbcb is from
// the active queue, we need to check that losing the tail of the
// will not swallow up any of our reserved space.
//
if (!FlagOn( Lfcb->Flags, LFCB_PACK_LOG )
&& FlagOn( ThisLbcb->LbcbFlags, LBCB_ON_ACTIVE_QUEUE )) {
LONGLONG CurrentAvail;
LONGLONG UnusedBytes;
//
// Find the unused bytes.
//
UnusedBytes = 0;
LfsCurrentAvailSpace( Lfcb,
&CurrentAvail,
(PULONG)&UnusedBytes );
CurrentAvail = CurrentAvail - Lfcb->TotalUndoCommitment;
if ( UnusedBytes > CurrentAvail ) {
DebugTrace( -1, Dbg, "Have to preserve these bytes for possible aborts\n", 0 );
ExRaiseStatus( STATUS_LOG_FILE_FULL );
}
//
// We want to make sure we don't write any more data into this
// page. Remove this from the active queue.
//
RemoveEntryList( &ThisLbcb->ActiveLinks );
ClearFlag( ThisLbcb->LbcbFlags, LBCB_ON_ACTIVE_QUEUE );
}
//
// We now have the Lbcb we want to flush to disk.
//
LfsFlushLbcb( Lfcb, ThisLbcb );
}
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,
&PageHeader,
&PageHeaderBcb );
//
// 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 );
KeBugCheck( FILE_SYSTEM );
}
//
// 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();
//
// 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 );
} 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;
}
