NTSTATUS
CdCommonCleanup (
IN PIRP_CONTEXT IrpContext,
IN PIRP Irp
)
/*++
Routine Description:
This is the common routine for cleanup of a file/directory called by both
the fsd and fsp threads.
Cleanup is invoked whenever the last handle to a file object is closed.
This is different than the Close operation which is invoked when the last
reference to a file object is deleted.
The function of cleanup is to essentially "cleanup" the file/directory
after a user is done with it. The Fcb/Dcb remains around (because MM
still has the file object referenced) but is now available for another
user to open (i.e., as far as the user is concerned the is now closed).
See close for a more complete description of what close does.
We do no synchronization in this routine until we get to the point
where we modify the counts, share access and volume lock field.
We need to update the Fcb and Vcb to show that a user handle has been closed.
The following structures and fields are affected.
Vcb:
VolumeLockFileObject - Did the user lock the volume with this file object.
VcbState - Check if we are unlocking the volume here.
VcbCleanup - Count of outstanding handles on the volume.
DirNotifyQueue - If this file object has pending DirNotify Irps.
Fcb:
ShareAccess - If this is a user handle.
FcbCleanup - Count of outstanding handles on this Fcb.
Oplock - Any outstanding oplocks on this file object.
FileLock - Any outstanding filelocks on this file object.
Arguments:
Irp - Supplies the Irp to process
Return Value:
NTSTATUS - The return status for the operation.
--*/
{
PFILE_OBJECT FileObject;
TYPE_OF_OPEN TypeOfOpen;
BOOLEAN SendUnlockNotification = FALSE;
BOOLEAN AttemptTeardown;
PVCB Vcb;
PFCB Fcb;
PCCB Ccb;
KIRQL SavedIrql;
ASSERT_IRP_CONTEXT( IrpContext );
ASSERT_IRP( Irp );
//
// If we were called with our file system device object instead of a
// volume device object, just complete this request with STATUS_SUCCESS.
//
if (IrpContext->Vcb == NULL) {
CdCompleteRequest( IrpContext, Irp, STATUS_SUCCESS );
return STATUS_SUCCESS;
}
//
// Get the file object out of the Irp and decode the type of open.
//
FileObject = IoGetCurrentIrpStackLocation( Irp )->FileObject;
TypeOfOpen = CdDecodeFileObject( IrpContext,
FileObject,
&Fcb,
&Ccb );
//
// No work here for either an UnopenedFile object or a StreamFileObject.
//
if (TypeOfOpen <= StreamFileOpen) {
CdCompleteRequest( IrpContext, Irp, STATUS_SUCCESS );
return STATUS_SUCCESS;
}
//
// Keep a local pointer to the Vcb.
//
Vcb = Fcb->Vcb;
//
// Synchronise with reads while we set the cleanup complete
// flag on this fileobject. Once this flag is set, any further
// reads will be rejected (CdVerifyFcbOperation)
//
CdAcquireFileExclusive( IrpContext, Fcb);
//
// Set the flag in the FileObject to indicate that cleanup is complete.
//
SetFlag( FileObject->Flags, FO_CLEANUP_COMPLETE );
CdReleaseFile( IrpContext, Fcb);
//
// Acquire the current file.
//
CdAcquireFcbExclusive( IrpContext, Fcb, FALSE );
//
// Use a try-finally to facilitate cleanup.
//
try {
//
// Case on the type of open that we are trying to cleanup.
//
switch (TypeOfOpen) {
case UserDirectoryOpen:
//
// Check if we need to complete any dir notify Irps on this file object.
//
FsRtlNotifyCleanup( Vcb->NotifySync,
&Vcb->DirNotifyList,
Ccb );
break;
case UserFileOpen:
//
// Coordinate the cleanup operation with the oplock state.
// Oplock cleanup operations can always cleanup immediately so no
// need to check for STATUS_PENDING.
//
FsRtlCheckOplock( &Fcb->Oplock,
Irp,
IrpContext,
NULL,
NULL );
//
// Unlock all outstanding file locks.
//
if (Fcb->FileLock != NULL) {
FsRtlFastUnlockAll( Fcb->FileLock,
FileObject,
IoGetRequestorProcess( Irp ),
NULL );
}
//
// Cleanup the cache map.
//
CcUninitializeCacheMap( FileObject, NULL, NULL );
//
// Check the fast io state.
//
CdLockFcb( IrpContext, Fcb );
Fcb->IsFastIoPossible = CdIsFastIoPossible( Fcb );
CdUnlockFcb( IrpContext, Fcb );
break;
case UserVolumeOpen :
break;
default :
CdBugCheck( TypeOfOpen, 0, 0 );
}
//
// Now lock the Vcb in order to modify the fields in the in-memory
// structures.
//
CdLockVcb( IrpContext, Vcb );
//
// Decrement the cleanup counts in the Vcb and Fcb.
//
CdDecrementCleanupCounts( IrpContext, Fcb );
//
// If the cleanup count hit zero and the volume is not mounted, we
// will want to try to spark teardown.
//
AttemptTeardown = (Vcb->VcbCleanup == 0 && Vcb->VcbCondition == VcbNotMounted);
//
// If this file object has locked the volume then perform the unlock operation.
// We do this regardless of explicit or implicit (no share DASD open) lock.
//
if (FileObject == Vcb->VolumeLockFileObject) {
ASSERT( FlagOn( Vcb->VcbState, VCB_STATE_LOCKED));
IoAcquireVpbSpinLock( &SavedIrql );
ClearFlag( Vcb->Vpb->Flags, VPB_LOCKED);
ClearFlag( Vcb->VcbState, VCB_STATE_LOCKED );
Vcb->VolumeLockFileObject = NULL;
SendUnlockNotification = TRUE;
IoReleaseVpbSpinLock( SavedIrql );
}
CdUnlockVcb( IrpContext, Vcb );
//
// We must clean up the share access at this time, since we may not
// get a Close call for awhile if the file was mapped through this
// File Object.
//
IoRemoveShareAccess( FileObject, &Fcb->ShareAccess );
} finally {
CdReleaseFcb( IrpContext, Fcb );
if (SendUnlockNotification) {
FsRtlNotifyVolumeEvent( FileObject, FSRTL_VOLUME_UNLOCK );
}
}
//
// If appropriate, try to spark teardown by purging the volume. Should
// this very fileobject we were cleaning up be the last reason for the
// volume to remain, teardown will commence on completion of this Irp.
//
if (AttemptTeardown) {
CdAcquireVcbExclusive( IrpContext, Vcb, FALSE );
try {
CdPurgeVolume( IrpContext, Vcb, FALSE );
} finally {
CdReleaseVcb( IrpContext, Vcb );
}
}
//
// If this is a normal termination then complete the request
//
CdCompleteRequest( IrpContext, Irp, STATUS_SUCCESS );
return STATUS_SUCCESS;
}
BOOLEAN
CdCheckForDismount (
IN PIRP_CONTEXT IrpContext,
IN PVCB Vcb,
IN BOOLEAN Force
)
/*++
Routine Description:
This routine is called to check if a volume is ready for dismount. This
occurs when only file system references are left on the volume.
If the dismount is not currently underway and the user reference count
has gone to zero then we can begin the dismount.
If the dismount is in progress and there are no references left on the
volume (we check the Vpb for outstanding references as well to catch
any create calls dispatched to the file system) then we can delete
the Vcb.
Arguments:
Vcb - Vcb for the volume to try to dismount.
Force - Whether we will force this volume to be dismounted.
Return Value:
BOOLEAN - True if the Vcb was not gone by the time this function finished,
False if it was deleted.
This is only a trustworthy indication to the caller if it had the vcb
exclusive itself.
--*/
{
BOOLEAN UnlockVcb = TRUE;
BOOLEAN VcbPresent = TRUE;
KIRQL SavedIrql;
ASSERT_IRP_CONTEXT( IrpContext );
ASSERT_VCB( Vcb );
ASSERT_EXCLUSIVE_CDDATA;
//
// Acquire and lock this Vcb to check the dismount state.
//
CdAcquireVcbExclusive( IrpContext, Vcb, FALSE );
//
// Lets get rid of any pending closes for this volume.
//
CdFspClose( Vcb );
CdLockVcb( IrpContext, Vcb );
//
// If the dismount is not already underway then check if the
// user reference count has gone to zero or we are being forced
// to disconnect. If so start the teardown on the Vcb.
//
if (Vcb->VcbCondition != VcbDismountInProgress) {
if (Vcb->VcbUserReference <= CDFS_RESIDUAL_USER_REFERENCE || Force) {
CdUnlockVcb( IrpContext, Vcb );
UnlockVcb = FALSE;
VcbPresent = CdDismountVcb( IrpContext, Vcb );
}
//
// If the teardown is underway and there are absolutely no references
// remaining then delete the Vcb. References here include the
// references in the Vcb and Vpb.
//
} else if (Vcb->VcbReference == 0) {
IoAcquireVpbSpinLock( &SavedIrql );
//
// If there are no file objects and no reference counts in the
// Vpb we can delete the Vcb. Don't forget that we have the
// last reference in the Vpb.
//
if (Vcb->Vpb->ReferenceCount == 1) {
IoReleaseVpbSpinLock( SavedIrql );
CdUnlockVcb( IrpContext, Vcb );
UnlockVcb = FALSE;
CdDeleteVcb( IrpContext, Vcb );
VcbPresent = FALSE;
} else {
IoReleaseVpbSpinLock( SavedIrql );
}
}
//
// Unlock the Vcb if still held.
//
if (UnlockVcb) {
CdUnlockVcb( IrpContext, Vcb );
}
//
// Release any resources still acquired.
//
if (VcbPresent) {
CdReleaseVcb( IrpContext, Vcb );
}
return VcbPresent;
}
BOOLEAN
CdDismountVcb (
IN PIRP_CONTEXT IrpContext,
IN PVCB Vcb
)
/*++
Routine Description:
This routine is called when all of the user references to a volume are
gone. We will initiate all of the teardown any system resources.
If all of the references to this volume are gone at the end of this routine
then we will complete the teardown of this Vcb and mark the current Vpb
as not mounted. Otherwise we will allocated a new Vpb for this device
and keep the current Vpb attached to the Vcb.
Arguments:
Vcb - Vcb for the volume to dismount.
Return Value:
BOOLEAN - TRUE if we didn't delete the Vcb, FALSE otherwise.
--*/
{
PVPB OldVpb;
BOOLEAN VcbPresent = TRUE;
KIRQL SavedIrql;
BOOLEAN FinalReference;
ASSERT_EXCLUSIVE_CDDATA;
ASSERT_EXCLUSIVE_VCB( Vcb );
CdLockVcb( IrpContext, Vcb );
//
// We should only take this path once.
//
ASSERT( Vcb->VcbCondition != VcbDismountInProgress );
//
// Mark the Vcb as DismountInProgress.
//
Vcb->VcbCondition = VcbDismountInProgress;
if (Vcb->XASector != NULL) {
CdFreePool( &Vcb->XASector );
Vcb->XASector = 0;
Vcb->XADiskOffset = 0;
}
//
// Remove our reference to the internal Fcb's. The Fcb's will then
// be removed in the purge path below.
//
if (Vcb->RootIndexFcb != NULL) {
Vcb->RootIndexFcb->FcbReference -= 1;
Vcb->RootIndexFcb->FcbUserReference -= 1;
}
if (Vcb->PathTableFcb != NULL) {
Vcb->PathTableFcb->FcbReference -= 1;
Vcb->PathTableFcb->FcbUserReference -= 1;
}
if (Vcb->VolumeDasdFcb != NULL) {
Vcb->VolumeDasdFcb->FcbReference -= 1;
Vcb->VolumeDasdFcb->FcbUserReference -= 1;
}
CdUnlockVcb( IrpContext, Vcb );
//
// Purge the volume.
//
CdPurgeVolume( IrpContext, Vcb, TRUE );
//
// Empty the delayed and async close queues.
//
CdFspClose( Vcb );
OldVpb = Vcb->Vpb;
//
// Remove the mount volume reference.
//
CdLockVcb( IrpContext, Vcb );
Vcb->VcbReference -= 1;
//
// Acquire the Vpb spinlock to check for Vpb references.
//
IoAcquireVpbSpinLock( &SavedIrql );
//
// Remember if this is the last reference on this Vcb. We incremented
// the count on the Vpb earlier so we get one last crack it. If our
// reference has gone to zero but the vpb reference count is greater
// than zero then the Io system will be responsible for deleting the
// Vpb.
//
FinalReference = (BOOLEAN) ((Vcb->VcbReference == 0) &&
(OldVpb->ReferenceCount == 1));
//
// There is a reference count in the Vpb and in the Vcb. We have
// incremented the reference count in the Vpb to make sure that
// we have last crack at it. If this is a failed mount then we
// want to return the Vpb to the IO system to use for the next
// mount request.
//
if (OldVpb->RealDevice->Vpb == OldVpb) {
//
// If not the final reference then swap out the Vpb. We must
// preserve the REMOVE_PENDING flag so that the device is
// not remounted in the middle of a PnP remove operation.
//
if (!FinalReference) {
ASSERT( Vcb->SwapVpb != NULL );
Vcb->SwapVpb->Type = IO_TYPE_VPB;
Vcb->SwapVpb->Size = sizeof( VPB );
Vcb->SwapVpb->RealDevice = OldVpb->RealDevice;
Vcb->SwapVpb->RealDevice->Vpb = Vcb->SwapVpb;
Vcb->SwapVpb->Flags = FlagOn( OldVpb->Flags, VPB_REMOVE_PENDING );
IoReleaseVpbSpinLock( SavedIrql );
//
// Indicate we used up the swap.
//
Vcb->SwapVpb = NULL;
CdUnlockVcb( IrpContext, Vcb );
//
// We want to leave the Vpb for the IO system. Mark it
// as being not mounted. Go ahead and delete the Vcb as
// well.
//
} else {
//
// Make sure to remove the last reference on the Vpb.
//
OldVpb->ReferenceCount -= 1;
OldVpb->DeviceObject = NULL;
ClearFlag( Vcb->Vpb->Flags, VPB_MOUNTED );
ClearFlag( Vcb->Vpb->Flags, VPB_LOCKED );
//
// Clear the Vpb flag so we know not to delete it.
//
Vcb->Vpb = NULL;
IoReleaseVpbSpinLock( SavedIrql );
CdUnlockVcb( IrpContext, Vcb );
CdDeleteVcb( IrpContext, Vcb );
VcbPresent = FALSE;
}
//
// Someone has already swapped in a new Vpb. If this is the final reference
// then the file system is responsible for deleting the Vpb.
//
} else if (FinalReference) {
//
// Make sure to remove the last reference on the Vpb.
//
OldVpb->ReferenceCount -= 1;
IoReleaseVpbSpinLock( SavedIrql );
CdUnlockVcb( IrpContext, Vcb );
CdDeleteVcb( IrpContext, Vcb );
VcbPresent = FALSE;
//
// The current Vpb is no longer the Vpb for the device (the IO system
// has already allocated a new one). We leave our reference in the
// Vpb and will be responsible for deleting it at a later time.
//
} else {
IoReleaseVpbSpinLock( SavedIrql );
CdUnlockVcb( IrpContext, Vcb );
}
//
// Let our caller know whether the Vcb is still present.
//
return VcbPresent;
}
BOOLEAN
CdCommonClosePrivate (
IN PIRP_CONTEXT IrpContext,
IN PVCB Vcb,
IN PFCB Fcb,
IN ULONG UserReference,
IN BOOLEAN FromFsd
)
/*++
Routine Description:
This is the worker routine for the close operation. We can be called in
an Fsd thread or from a worker Fsp thread. If called from the Fsd thread
then we acquire the resources without waiting. Otherwise we know it is
safe to wait.
We check to see whether we should post this request to the delayed close
queue. If we are to process the close here then we acquire the Vcb and
Fcb. We will adjust the counts and call our teardown routine to see
if any of the structures should go away.
Arguments:
Vcb - Vcb for this volume.
Fcb - Fcb for this request.
UserReference - Number of user references for this file object. This is
zero for an internal stream.
FromFsd - This request was called from an Fsd thread. Indicates whether
we should wait to acquire resources.
DelayedClose - Address to store whether we should try to put this on
the delayed close queue. Ignored if this routine can process this
close.
Return Value:
BOOLEAN - TRUE if this thread processed the close, FALSE otherwise.
--*/
{
BOOLEAN RemovedFcb;
PAGED_CODE();
ASSERT_IRP_CONTEXT( IrpContext );
ASSERT_FCB( Fcb );
//
// Try to acquire the Vcb and Fcb. If we can't acquire them then return
// and let our caller know he should post the request to the async
// queue.
//
if (CdAcquireVcbShared( IrpContext, Vcb, FromFsd )) {
if (!CdAcquireFcbExclusive( IrpContext, Fcb, FromFsd )) {
//
// We couldn't get the Fcb. Release the Vcb and let our caller
// know to post this request.
//
CdReleaseVcb( IrpContext, Vcb );
return FALSE;
}
//
// We didn't get the Vcb. Let our caller know to post this request.
//
} else {
return FALSE;
}
//
// Lock the Vcb and decrement the reference counts.
//
CdLockVcb( IrpContext, Vcb );
CdDecrementReferenceCounts( IrpContext, Fcb, 1, UserReference );
CdUnlockVcb( IrpContext, Vcb );
//
// Call our teardown routine to see if this object can go away.
// If we don't remove the Fcb then release it.
//
CdTeardownStructures( IrpContext, Fcb, &RemovedFcb );
if (!RemovedFcb) {
CdReleaseFcb( IrpContext, Fcb );
}
//
// Release the Vcb and return to our caller. Let him know we completed
// this request.
//
CdReleaseVcb( IrpContext, Vcb );
return TRUE;
}
NTSTATUS
CdPnpSurpriseRemove (
_Inout_ PIRP_CONTEXT IrpContext,
_Inout_ PIRP Irp,
_Inout_ PVCB Vcb
)
/*++
Routine Description:
This routine handles the PnP surprise remove operation. This is another
type of notification that the underlying storage device for the volume we
have is gone, and is excellent indication that the volume will never reappear.
The filesystem is responsible for initiation or completion the dismount.
For the most part, only "real" drivers care about the distinction of a
surprise remove, which is a result of our noticing that a user (usually)
physically reached into the machine and pulled something out.
Surprise will be followed by a Remove when all references have been shut down.
Arguments:
Irp - Supplies the Irp to process
Vcb - Supplies the volume being removed.
Return Value:
NTSTATUS - The return status for the operation
--*/
{
NTSTATUS Status;
KEVENT Event;
BOOLEAN VcbPresent = TRUE;
PAGED_CODE();
ASSERT_EXCLUSIVE_CDDATA;
//
// SURPRISE - a device was physically yanked away without
// any warning. This means external forces.
//
CdAcquireVcbExclusive( IrpContext, Vcb, FALSE );
//
// Invalidate the volume right now.
//
// The intent here is to make every subsequent operation
// on the volume fail and grease the rails toward dismount.
// By definition there is no going back from a SURPRISE.
//
CdLockVcb( IrpContext, Vcb );
if (Vcb->VcbCondition != VcbDismountInProgress) {
CdUpdateVcbCondition( Vcb, VcbInvalid);
}
CdUnlockVcb( IrpContext, Vcb );
//
// We need to pass this down before starting the dismount, which
// could disconnect us immediately from the stack.
//
//
// Get the next stack location, and copy over the stack location
//
IoCopyCurrentIrpStackLocationToNext( Irp );
//
// Set up the completion routine
//
KeInitializeEvent( &Event, NotificationEvent, FALSE );
IoSetCompletionRoutine( Irp,
CdPnpCompletionRoutine,
&Event,
TRUE,
TRUE,
TRUE );
//
// Send the request and wait.
//
Status = IoCallDriver(Vcb->TargetDeviceObject, Irp);
if (Status == STATUS_PENDING) {
(VOID)KeWaitForSingleObject( &Event,
Executive,
KernelMode,
FALSE,
NULL );
Status = Irp->IoStatus.Status;
}
//
// Now make our dismount happen. This may not vaporize the
// Vcb, of course, since there could be any number of handles
// outstanding since this is an out of band notification.
//
VcbPresent = CdCheckForDismount( IrpContext, Vcb, TRUE );
//
// Release the Vcb if it could still remain.
//
if (VcbPresent) {
CdReleaseVcb( IrpContext, Vcb );
}
else {
_Analysis_assume_lock_not_held_(Vcb->VcbResource);
}
CdReleaseCdData( IrpContext );
//
// Cleanup our IrpContext and complete the IRP.
//
CdCompleteRequest( IrpContext, Irp, Status );
return Status;
}
NTSTATUS
CdPnpRemove (
_Inout_ PIRP_CONTEXT IrpContext,
_Inout_ PIRP Irp,
_Inout_ PVCB Vcb
)
/*++
Routine Description:
This routine handles the PnP remove operation. This is our notification
that the underlying storage device for the volume we have is gone, and
an excellent indication that the volume will never reappear. The filesystem
is responsible for initiation or completion the dismount.
Arguments:
Irp - Supplies the Irp to process
Vcb - Supplies the volume being removed.
Return Value:
NTSTATUS - The return status for the operation
--*/
{
NTSTATUS Status;
KEVENT Event;
BOOLEAN VcbPresent = TRUE;
PAGED_CODE();
ASSERT_EXCLUSIVE_CDDATA;
//
// REMOVE - a storage device is now gone. We either got
// QUERY'd and said yes OR got a SURPRISE OR a storage
// stack failed to spin back up from a sleep/stop state
// (the only case in which this will be the first warning).
//
// Note that it is entirely unlikely that we will be around
// for a REMOVE in the first two cases, as we try to intiate
// dismount.
//
//
// Acquire the global resource so that we can try to vaporize
// the volume, and the vcb resource itself.
//
CdAcquireVcbExclusive( IrpContext, Vcb, FALSE );
//
// The device will be going away. Remove our lock and find
// out if we ever had one in the first place.
//
Status = CdUnlockVolumeInternal( IrpContext, Vcb, NULL );
//
// If the volume had not been locked, we must invalidate the
// volume to ensure it goes away properly. The remove will
// succeed.
//
if (!NT_SUCCESS( Status )) {
CdLockVcb( IrpContext, Vcb );
if (Vcb->VcbCondition != VcbDismountInProgress) {
CdUpdateVcbCondition( Vcb, VcbInvalid);
}
CdUnlockVcb( IrpContext, Vcb );
Status = STATUS_SUCCESS;
}
//
// We need to pass this down before starting the dismount, which
// could disconnect us immediately from the stack.
//
//
// Get the next stack location, and copy over the stack location
//
IoCopyCurrentIrpStackLocationToNext( Irp );
//
// Set up the completion routine
//
KeInitializeEvent( &Event, NotificationEvent, FALSE );
IoSetCompletionRoutine( Irp,
CdPnpCompletionRoutine,
&Event,
TRUE,
TRUE,
TRUE );
//
// Send the request and wait.
//
Status = IoCallDriver(Vcb->TargetDeviceObject, Irp);
if (Status == STATUS_PENDING) {
(VOID)KeWaitForSingleObject( &Event,
Executive,
KernelMode,
FALSE,
NULL );
Status = Irp->IoStatus.Status;
}
//
// Now make our dismount happen. This may not vaporize the
// Vcb, of course, since there could be any number of handles
// outstanding if we were not preceeded by a QUERY.
//
// PnP will take care of disconnecting this stack if we
// couldn't get off of it immediately.
//
VcbPresent = CdCheckForDismount( IrpContext, Vcb, TRUE );
//
// Release the Vcb if it could still remain.
//
if (VcbPresent) {
CdReleaseVcb( IrpContext, Vcb );
}
else {
_Analysis_assume_lock_not_held_(Vcb->VcbResource);
}
CdReleaseCdData( IrpContext );
//
// Cleanup our IrpContext and complete the IRP.
//
CdCompleteRequest( IrpContext, Irp, Status );
return Status;
}
NTSTATUS
CdPnpQueryRemove (
_Inout_ PIRP_CONTEXT IrpContext,
_Inout_ PIRP Irp,
_Inout_ PVCB Vcb
)
/*++
Routine Description:
This routine handles the PnP query remove operation. The filesystem
is responsible for answering whether there are any reasons it sees
that the volume can not go away (and the device removed). Initiation
of the dismount begins when we answer yes to this question.
Query will be followed by a Cancel or Remove.
Arguments:
Irp - Supplies the Irp to process
Vcb - Supplies the volume being queried.
Return Value:
NTSTATUS - The return status for the operation
--*/
{
NTSTATUS Status;
KEVENT Event;
BOOLEAN VcbPresent = TRUE;
PAGED_CODE();
ASSERT_EXCLUSIVE_CDDATA;
//
// Having said yes to a QUERY, any communication with the
// underlying storage stack is undefined (and may block)
// until the bounding CANCEL or REMOVE is sent.
//
// Acquire the global resource so that we can try to vaporize the volume,
// and the vcb resource itself.
//
CdAcquireVcbExclusive( IrpContext, Vcb, FALSE );
//
// Drop a reference on the Vcb to keep it around after we drop the locks.
//
CdLockVcb( IrpContext, Vcb);
Vcb->VcbReference += 1;
CdUnlockVcb( IrpContext, Vcb);
CdReleaseCdData( IrpContext);
Status = CdLockVolumeInternal( IrpContext, Vcb, NULL );
//
// Reacquire the global lock, which means dropping the Vcb resource.
//
CdReleaseVcb( IrpContext, Vcb );
CdAcquireCdData( IrpContext );
CdAcquireVcbExclusive( IrpContext, Vcb, FALSE );
//
// Remove our extra reference.
//
CdLockVcb( IrpContext, Vcb);
Vcb->VcbReference -= 1;
CdUnlockVcb( IrpContext, Vcb);
if (NT_SUCCESS( Status )) {
//
// We need to pass this down before starting the dismount, which
// could disconnect us immediately from the stack.
//
//
// Get the next stack location, and copy over the stack location
//
IoCopyCurrentIrpStackLocationToNext( Irp );
//
// Set up the completion routine
//
KeInitializeEvent( &Event, NotificationEvent, FALSE );
IoSetCompletionRoutine( Irp,
CdPnpCompletionRoutine,
&Event,
TRUE,
TRUE,
TRUE );
//
// Send the request and wait.
//
Status = IoCallDriver(Vcb->TargetDeviceObject, Irp);
if (Status == STATUS_PENDING) {
(VOID)KeWaitForSingleObject( &Event,
Executive,
KernelMode,
FALSE,
NULL );
Status = Irp->IoStatus.Status;
}
//
// Now if no one below us failed already, initiate the dismount
// on this volume, make it go away. PnP needs to see our internal
// streams close and drop their references to the target device.
//
// Since we were able to lock the volume, we are guaranteed to
// move this volume into dismount state and disconnect it from
// the underlying storage stack. The force on our part is actually
// unnecesary, though complete.
//
// What is not strictly guaranteed, though, is that the closes
// for the metadata streams take effect synchronously underneath
// of this call. This would leave references on the target device
// even though we are disconnected!
//
if (NT_SUCCESS( Status )) {
VcbPresent = CdCheckForDismount( IrpContext, Vcb, TRUE );
NT_ASSERT( !VcbPresent || Vcb->VcbCondition == VcbDismountInProgress );
}
//
// Note: Normally everything will complete and the internal streams will
// vaporise. However there is some code in the system which drops additional
// references on fileobjects, including our internal stream file objects,
// for (WMI) tracing purposes. If that happens to run concurrently with our
// teardown, our internal streams will not vaporise until those references
// are removed. So it's possible that the volume still remains at this
// point. The pnp query remove will fail due to our references on the device.
// To be cleaner we will return an error here. We could pend the pnp
// IRP until the volume goes away, but since we don't know when that will
// be, and this is a very rare case, we'll just fail the query.
//
// The reason this is the case is that handles/fileobjects place a reference
// on the device objects they overly. In the filesystem case, these references
// are on our target devices. PnP correcly thinks that if references remain
// on the device objects in the stack that someone has a handle, and that this
// counts as a reason to not succeed the query - even though every interrogated
// driver thinks that it is OK.
//
if (NT_SUCCESS( Status) && VcbPresent && (Vcb->VcbReference != 0)) {
Status = STATUS_DEVICE_BUSY;
}
}
//
// Release the Vcb if it could still remain.
//
if (VcbPresent) {
CdReleaseVcb( IrpContext, Vcb );
}
else {
_Analysis_assume_lock_not_held_(Vcb->VcbResource);
}
CdReleaseCdData( IrpContext );
//
// Cleanup our IrpContext and complete the IRP if neccesary.
//
CdCompleteRequest( IrpContext, Irp, Status );
return Status;
}
VOID
CdFindPrefix (
_In_ PIRP_CONTEXT IrpContext,
_Inout_ PFCB *CurrentFcb,
_Inout_ PUNICODE_STRING RemainingName,
_In_ BOOLEAN IgnoreCase
)
/*++
Routine Description:
This routine begins from the given CurrentFcb and walks through all of
components of the name looking for the longest match in the prefix
splay trees. The search is relative to the starting Fcb so the
full name may not begin with a '\'. On return this routine will
update Current Fcb with the lowest point it has travelled in the
tree. It will also hold only that resource on return and it must
hold that resource.
Arguments:
CurrentFcb - Address to store the lowest Fcb we find on this search.
On return we will have acquired this Fcb. On entry this is the
Fcb to examine.
RemainingName - Supplies a buffer to store the exact case of the name being
searched for. Initially will contain the upcase name based on the
IgnoreCase flag.
IgnoreCase - Indicates if we are doing a case-insensitive compare.
Return Value:
None
--*/
{
UNICODE_STRING LocalRemainingName;
UNICODE_STRING FinalName;
PNAME_LINK NameLink;
PPREFIX_ENTRY PrefixEntry;
PAGED_CODE();
//
// Make a local copy of the input strings.
//
LocalRemainingName = *RemainingName;
//
// Loop until we find the longest matching prefix.
//
while (TRUE) {
//
// If there are no characters left or we are not at an IndexFcb then
// return immediately.
//
if ((LocalRemainingName.Length == 0) ||
(SafeNodeType( *CurrentFcb ) != CDFS_NTC_FCB_INDEX)) {
return;
}
//
// Split off the next component from the name.
//
CdDissectName( IrpContext,
&LocalRemainingName,
&FinalName );
//
// Check if this name is in the splay tree for this Scb.
//
if (IgnoreCase) {
NameLink = CdFindNameLink( IrpContext,
&(*CurrentFcb)->IgnoreCaseRoot,
&FinalName );
//
// Get the prefix entry from this NameLink. Don't access any
// fields within it until we verify we have a name link.
//
PrefixEntry = (PPREFIX_ENTRY) CONTAINING_RECORD( NameLink,
PREFIX_ENTRY,
IgnoreCaseName );
} else {
NameLink = CdFindNameLink( IrpContext,
&(*CurrentFcb)->ExactCaseRoot,
&FinalName );
PrefixEntry = (PPREFIX_ENTRY) CONTAINING_RECORD( NameLink,
PREFIX_ENTRY,
ExactCaseName );
}
//
// If we didn't find a match then exit.
//
if (NameLink == NULL) { return; }
//
// If this is a case-insensitive match then copy the exact case of the name into
// the input buffer.
//
if (IgnoreCase) {
RtlCopyMemory( FinalName.Buffer,
PrefixEntry->ExactCaseName.FileName.Buffer,
PrefixEntry->ExactCaseName.FileName.Length );
}
//
// Update the caller's remaining name string to reflect the fact that we found
// a match.
//
*RemainingName = LocalRemainingName;
//
// Move down to the next component in the tree. Acquire without waiting.
// If this fails then lock the Fcb to reference this Fcb and then drop
// the parent and acquire the child.
//
if (!CdAcquireFcbExclusive( IrpContext, PrefixEntry->Fcb, TRUE )) {
//
// If we can't wait then raise CANT_WAIT.
//
if (!FlagOn( IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT )) {
CdRaiseStatus( IrpContext, STATUS_CANT_WAIT );
}
CdLockVcb( IrpContext, IrpContext->Vcb );
PrefixEntry->Fcb->FcbReference += 1;
CdUnlockVcb( IrpContext, IrpContext->Vcb );
CdReleaseFcb( IrpContext, *CurrentFcb );
CdAcquireFcbExclusive( IrpContext, PrefixEntry->Fcb, FALSE );
CdLockVcb( IrpContext, IrpContext->Vcb );
PrefixEntry->Fcb->FcbReference -= 1;
CdUnlockVcb( IrpContext, IrpContext->Vcb );
} else {
CdReleaseFcb( IrpContext, *CurrentFcb );
}
*CurrentFcb = PrefixEntry->Fcb;
}
}
