LARGE_INTEGER
CcGetDirtyPages (
__in PVOID LogHandle,
__in PDIRTY_PAGE_ROUTINE DirtyPageRoutine,
__in PVOID Context1,
__in PVOID Context2
)
/*++
Routine Description:
This routine may be called to return all of the dirty pages in all files
for a given log handle. Each page is returned by an individual call to
the Dirty Page Routine. The Dirty Page Routine is defined by a prototype
in ntos\inc\cache.h.
Arguments:
LogHandle - Log Handle which must match the log handle previously stored
for all files which are to be returned.
DirtyPageRoutine -- The routine to call as each dirty page for this log
handle is found.
Context1 - First context parameter to be passed to the Dirty Page Routine.
Context2 - First context parameter to be passed to the Dirty Page Routine.
Return Value:
LARGE_INTEGER - Oldest Lsn found of all the dirty pages, or 0 if no dirty pages
--*/
{
PSHARED_CACHE_MAP SharedCacheMap;
PBCB Bcb, BcbToUnpin = NULL;
KLOCK_QUEUE_HANDLE LockHandle;
LARGE_INTEGER SavedFileOffset, SavedOldestLsn, SavedNewestLsn;
ULONG SavedByteLength;
LARGE_INTEGER OldestLsn = {0,0};
//
// Synchronize with changes to the SharedCacheMap list.
//
CcAcquireMasterLock( &LockHandle.OldIrql );
SharedCacheMap = CONTAINING_RECORD( CcDirtySharedCacheMapList.SharedCacheMapLinks.Flink,
SHARED_CACHE_MAP,
SharedCacheMapLinks );
//
// Use try/finally for cleanup. The only spot where we can raise is out of the
// filesystem callback, but we have the exception handler out here so we aren't
// constantly setting/unsetting it.
//
try {
while (&SharedCacheMap->SharedCacheMapLinks != &CcDirtySharedCacheMapList.SharedCacheMapLinks) {
//
// Skip over cursors, SharedCacheMaps for other LogHandles, and ones with
// no dirty pages
//
if (!FlagOn(SharedCacheMap->Flags, IS_CURSOR) && (SharedCacheMap->LogHandle == LogHandle) &&
(SharedCacheMap->DirtyPages != 0)) {
//
// This SharedCacheMap should stick around for a while in the dirty list.
//
CcIncrementOpenCount( SharedCacheMap, 'pdGS' );
SharedCacheMap->DirtyPages += 1;
CcReleaseMasterLock( LockHandle.OldIrql );
//
// Set our initial resume point and point to first Bcb in List.
//
KeAcquireInStackQueuedSpinLock( &SharedCacheMap->BcbSpinLock, &LockHandle );
Bcb = CONTAINING_RECORD( SharedCacheMap->BcbList.Flink, BCB, BcbLinks );
//
// Scan to the end of the Bcb list.
//
while (&Bcb->BcbLinks != &SharedCacheMap->BcbList) {
//
// If the Bcb is dirty, then capture the inputs for the
// callback routine so we can call without holding a spinlock.
//
if ((Bcb->NodeTypeCode == CACHE_NTC_BCB) && Bcb->Dirty) {
SavedFileOffset = Bcb->FileOffset;
SavedByteLength = Bcb->ByteLength;
SavedOldestLsn = Bcb->OldestLsn;
SavedNewestLsn = Bcb->NewestLsn;
//
// Increment PinCount so the Bcb sticks around
//
Bcb->PinCount += 1;
KeReleaseInStackQueuedSpinLock( &LockHandle );
//
// Any Bcb to unref from a previous loop?
//
if (BcbToUnpin != NULL) {
CcUnpinFileData( BcbToUnpin, TRUE, UNREF );
BcbToUnpin = NULL;
}
//
// Call the file system. This callback may raise status.
//
(*DirtyPageRoutine)( SharedCacheMap->FileObject,
&SavedFileOffset,
SavedByteLength,
&SavedOldestLsn,
&SavedNewestLsn,
Context1,
Context2 );
//
// Possibly update OldestLsn
//
if ((SavedOldestLsn.QuadPart != 0) &&
((OldestLsn.QuadPart == 0) || (SavedOldestLsn.QuadPart < OldestLsn.QuadPart ))) {
OldestLsn = SavedOldestLsn;
}
//
// Now reacquire the spinlock and scan from the resume point
// point to the next Bcb to return in the descending list.
//
KeAcquireInStackQueuedSpinLock( &SharedCacheMap->BcbSpinLock, &LockHandle );
//
// Normally the Bcb can stay around a while, but if not,
// we will just remember it for the next time we do not
// have the spin lock. We cannot unpin it now, because
// we would lose our place in the list.
//
// This is cheating, but it works and is sane since we're
// already traversing the bcb list - dropping the bcb count
// is OK, as long as we don't hit zero. Zero requires a
// slight bit more attention that shouldn't be replicated.
// (unmapping the view)
//
if (Bcb->PinCount > 1) {
Bcb->PinCount -= 1;
} else {
BcbToUnpin = Bcb;
}
}
Bcb = CONTAINING_RECORD( Bcb->BcbLinks.Flink, BCB, BcbLinks );
}
KeReleaseInStackQueuedSpinLock( &LockHandle );
//
// We need to unref any Bcb we are holding before moving on to
// the next SharedCacheMap, or else CcDeleteSharedCacheMap will
// also delete this Bcb.
//
if (BcbToUnpin != NULL) {
CcUnpinFileData( BcbToUnpin, TRUE, UNREF );
BcbToUnpin = NULL;
}
CcAcquireMasterLock( &LockHandle.OldIrql );
//
// Now release the SharedCacheMap, leaving it in the dirty list.
//
CcDecrementOpenCount( SharedCacheMap, 'pdGF' );
SharedCacheMap->DirtyPages -= 1;
}
//
// Now loop back for the next cache map.
//
SharedCacheMap =
CONTAINING_RECORD( SharedCacheMap->SharedCacheMapLinks.Flink,
SHARED_CACHE_MAP,
SharedCacheMapLinks );
}
CcReleaseMasterLock( LockHandle.OldIrql );
} finally {
//
// Drop the Bcb if we are being ejected. We are guaranteed that the
// only raise is from the callback, at which point we have an incremented
// pincount.
//
if (AbnormalTermination()) {
CcUnpinFileData( Bcb, TRUE, UNPIN );
}
}
return OldestLsn;
}
VOID
CcPrepareMdlWrite (
IN PFILE_OBJECT FileObject,
IN PLARGE_INTEGER FileOffset,
IN ULONG Length,
OUT PMDL *MdlChain,
OUT PIO_STATUS_BLOCK IoStatus
)
/*++
Routine Description:
This routine attempts to lock the specified file data in the cache
and return a description of it in an Mdl along with the correct
I/O status. Pages to be completely overwritten may be satisfied
with emtpy pages. It is *not* safe to call this routine from Dpc level.
This call is synchronous and raises on error.
When this call returns, the caller may immediately begin
to transfer data into the buffers via the Mdl.
When the call returns with TRUE, the pages described by the Mdl are
locked in memory, but not mapped in system space. If the caller
needs the pages mapped in system space, then it must map them.
On the subsequent call to CcMdlWriteComplete the pages will be
unmapped if they were mapped, and in any case unlocked and the Mdl
deallocated.
Arguments:
FileObject - Pointer to the file object for a file which was
opened with NO_INTERMEDIATE_BUFFERING clear, i.e., for
which CcInitializeCacheMap was called by the file system.
FileOffset - Byte offset in file for desired data.
Length - Length of desired data in bytes.
MdlChain - On output it returns a pointer to an Mdl chain describing
the desired data. Note that even if FALSE is returned,
one or more Mdls may have been allocated, as may be ascertained
by the IoStatus.Information field (see below).
IoStatus - Pointer to standard I/O status block to receive the status
for the in-transfer of the data. (STATUS_SUCCESS guaranteed
for cache hits, otherwise the actual I/O status is returned.)
The I/O Information Field indicates how many bytes have been
successfully locked down in the Mdl Chain.
Return Value:
None
--*/
{
PSHARED_CACHE_MAP SharedCacheMap;
PVOID CacheBuffer;
LARGE_INTEGER FOffset;
PMDL Mdl = NULL;
PMDL MdlTemp;
LARGE_INTEGER Temp;
ULONG SavedState = 0;
ULONG ZeroFlags = 0;
ULONG Information = 0;
KIRQL OldIrql;
ULONG ActivePage;
ULONG PageIsDirty;
PVACB Vacb = NULL;
DebugTrace(+1, me, "CcPrepareMdlWrite\n", 0 );
DebugTrace( 0, me, " FileObject = %08lx\n", FileObject );
DebugTrace2(0, me, " FileOffset = %08lx, %08lx\n", FileOffset->LowPart,
FileOffset->HighPart );
DebugTrace( 0, me, " Length = %08lx\n", Length );
//
// Get pointer to SharedCacheMap.
//
SharedCacheMap = FileObject->SectionObjectPointer->SharedCacheMap;
//
// See if we have an active Vacb, that we need to free.
//
GetActiveVacb( SharedCacheMap, OldIrql, Vacb, ActivePage, PageIsDirty );
//
// If there is an end of a page to be zeroed, then free that page now,
// so it does not cause our data to get zeroed. If there is an active
// page, free it so we have the correct ValidDataGoal.
//
if ((Vacb != NULL) || (SharedCacheMap->NeedToZero != NULL)) {
CcFreeActiveVacb( SharedCacheMap, Vacb, ActivePage, PageIsDirty );
Vacb = NULL;
}
FOffset = *FileOffset;
//
// Put try-finally around the loop to deal with exceptions
//
try {
//
// Not all of the transfer will come back at once, so we have to loop
// until the entire transfer is complete.
//
while (Length != 0) {
ULONG ReceivedLength;
LARGE_INTEGER BeyondLastByte;
//
// Map and see how much we could potentially access at this
// FileOffset, then cut it down if it is more than we need.
//
CacheBuffer = CcGetVirtualAddress( SharedCacheMap,
FOffset,
&Vacb,
&ReceivedLength );
if (ReceivedLength > Length) {
ReceivedLength = Length;
}
BeyondLastByte.QuadPart = FOffset.QuadPart + (LONGLONG)ReceivedLength;
//
// At this point we can calculate the ZeroFlags.
//
//
// We can always zero middle pages, if any.
//
ZeroFlags = ZERO_MIDDLE_PAGES;
//
// See if we are completely overwriting the first or last page.
//
if (((FOffset.LowPart & (PAGE_SIZE - 1)) == 0) &&
(ReceivedLength >= PAGE_SIZE)) {
ZeroFlags |= ZERO_FIRST_PAGE;
}
if ((BeyondLastByte.LowPart & (PAGE_SIZE - 1)) == 0) {
ZeroFlags |= ZERO_LAST_PAGE;
}
//
// See if the entire transfer is beyond valid data length,
// or at least starting from the second page.
//
Temp = FOffset;
Temp.LowPart &= ~(PAGE_SIZE -1);
ExAcquireFastLock( &SharedCacheMap->BcbSpinLock, &OldIrql );
Temp.QuadPart = SharedCacheMap->ValidDataGoal.QuadPart - Temp.QuadPart;
ExReleaseFastLock( &SharedCacheMap->BcbSpinLock, OldIrql );
if (Temp.QuadPart <= 0) {
ZeroFlags |= ZERO_FIRST_PAGE | ZERO_MIDDLE_PAGES | ZERO_LAST_PAGE;
} else if ((Temp.HighPart == 0) && (Temp.LowPart <= PAGE_SIZE)) {
ZeroFlags |= ZERO_MIDDLE_PAGES | ZERO_LAST_PAGE;
}
(VOID)CcMapAndRead( SharedCacheMap,
&FOffset,
ReceivedLength,
ZeroFlags,
TRUE,
CacheBuffer );
//
// Now attempt to allocate an Mdl to describe the mapped data.
//
DebugTrace( 0, mm, "IoAllocateMdl:\n", 0 );
DebugTrace( 0, mm, " BaseAddress = %08lx\n", CacheBuffer );
DebugTrace( 0, mm, " Length = %08lx\n", ReceivedLength );
Mdl = IoAllocateMdl( CacheBuffer,
ReceivedLength,
FALSE,
FALSE,
NULL );
DebugTrace( 0, mm, " <Mdl = %08lx\n", Mdl );
if (Mdl == NULL) {
DebugTrace( 0, 0, "Failed to allocate Mdl\n", 0 );
ExRaiseStatus( STATUS_INSUFFICIENT_RESOURCES );
}
DebugTrace( 0, mm, "MmProbeAndLockPages:\n", 0 );
DebugTrace( 0, mm, " Mdl = %08lx\n", Mdl );
MmDisablePageFaultClustering(&SavedState);
MmProbeAndLockPages( Mdl, KernelMode, IoWriteAccess );
MmEnablePageFaultClustering(SavedState);
SavedState = 0;
//
// Now that some data (maybe zeros) is locked in memory and
// set dirty, it is safe, and necessary for us to advance
// valid data goal, so that we will not subsequently ask
// for a zero page. Note if we are extending valid data,
// our caller has the file exclusive.
//
ExAcquireFastLock( &SharedCacheMap->BcbSpinLock, &OldIrql );
if (BeyondLastByte.QuadPart > SharedCacheMap->ValidDataGoal.QuadPart) {
SharedCacheMap->ValidDataGoal = BeyondLastByte;
}
ExReleaseFastLock( &SharedCacheMap->BcbSpinLock, OldIrql );
//
// Unmap the data now, now that the pages are locked down.
//
CcFreeVirtualAddress( Vacb );
Vacb = NULL;
//
// Now link the Mdl into the caller's chain
//
if ( *MdlChain == NULL ) {
*MdlChain = Mdl;
} else {
MdlTemp = CONTAINING_RECORD( *MdlChain, MDL, Next );
while (MdlTemp->Next != NULL) {
MdlTemp = MdlTemp->Next;
}
MdlTemp->Next = Mdl;
}
Mdl = NULL;
//
// Assume we did not get all the data we wanted, and set FOffset
// to the end of the returned data.
//
FOffset = BeyondLastByte;
//
// Update number of bytes transferred.
//
Information += ReceivedLength;
//
// Calculate length left to transfer.
//
Length -= ReceivedLength;
}
}
finally {
if (AbnormalTermination()) {
if (SavedState != 0) {
MmEnablePageFaultClustering(SavedState);
}
if (Vacb != NULL) {
CcFreeVirtualAddress( Vacb );
}
if (Mdl != NULL) {
IoFreeMdl( Mdl );
}
//
// Otherwise loop to deallocate the Mdls
//
FOffset = *FileOffset;
while (*MdlChain != NULL) {
MdlTemp = (*MdlChain)->Next;
DebugTrace( 0, mm, "MmUnlockPages/IoFreeMdl:\n", 0 );
DebugTrace( 0, mm, " Mdl = %08lx\n", *MdlChain );
MmUnlockPages( *MdlChain );
//
// Extract the File Offset for this part of the transfer, and
// tell the lazy writer to write these pages, since we have
// marked them dirty. Ignore the only exception (allocation
// error), and console ourselves for having tried.
//
CcSetDirtyInMask( SharedCacheMap, &FOffset, (*MdlChain)->ByteCount );
FOffset.QuadPart = FOffset.QuadPart + (LONGLONG)((*MdlChain)->ByteCount);
IoFreeMdl( *MdlChain );
*MdlChain = MdlTemp;
}
DebugTrace(-1, me, "CcPrepareMdlWrite -> Unwinding\n", 0 );
}
else {
IoStatus->Status = STATUS_SUCCESS;
IoStatus->Information = Information;
//
// Make sure the SharedCacheMap does not go away while
// the Mdl write is in progress. We decrment below.
//
CcAcquireMasterLock( &OldIrql );
CcIncrementOpenCount( SharedCacheMap, 'ldmP' );
CcReleaseMasterLock( OldIrql );
}
}
DebugTrace( 0, me, " <MdlChain = %08lx\n", *MdlChain );
DebugTrace(-1, me, "CcPrepareMdlWrite -> VOID\n", 0 );
return;
}
