close.c

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/*
 * PROJECT:     VFAT Filesystem
 * LICENSE:     GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
 * PURPOSE:     File close routines
 * COPYRIGHT:   Copyright 1998 Jason Filby <jasonfilby@yahoo.com>
 *              Copyright 2014-2018 Pierre Schweitzer <pierre@reactos.org>
 */
 
/* INCLUDES *****************************************************************/
 
#include "vfat.h"
 
#define NDEBUG
#include <debug.h>
 
/* FUNCTIONS ****************************************************************/
 
VOID
VfatCommonCloseFile(
    PDEVICE_EXTENSION DeviceExt,
    PVFATFCB pFcb)
{
    /* Nothing to do for volumes or for the FAT file object */
    if (BooleanFlagOn(pFcb->Flags, FCB_IS_FAT | FCB_IS_VOLUME))
    {
        return;
    }
 
    /* If cache is still initialized, release it
     * This only affects directories
     */
    if (pFcb->OpenHandleCount == 0 && BooleanFlagOn(pFcb->Flags, FCB_CACHE_INITIALIZED))
    {
        PFILE_OBJECT tmpFileObject;
        tmpFileObject = pFcb->FileObject;
        if (tmpFileObject != NULL)
        {
            pFcb->FileObject = NULL;
            CcUninitializeCacheMap(tmpFileObject, NULL, NULL);
            ClearFlag(pFcb->Flags, FCB_CACHE_INITIALIZED);
            ObDereferenceObject(tmpFileObject);
        }
    }
 
#ifdef KDBG
    pFcb->Flags |= FCB_CLOSED;
#endif
 
    /* Release the FCB, we likely cause its deletion */
    vfatReleaseFCB(DeviceExt, pFcb);
}
 
VOID
NTAPI
VfatCloseWorker(
    IN PDEVICE_OBJECT DeviceObject,
    IN PVOID Context)
{
    PLIST_ENTRY Entry;
    PVFATFCB pFcb;
    PDEVICE_EXTENSION Vcb;
    PVFAT_CLOSE_CONTEXT CloseContext;
    BOOLEAN ConcurrentDeletion;
 
    /* Start removing work items */
    ExAcquireFastMutex(&VfatGlobalData->CloseMutex);
    while (!IsListEmpty(&VfatGlobalData->CloseListHead))
    {
        Entry = RemoveHeadList(&VfatGlobalData->CloseListHead);
        CloseContext = CONTAINING_RECORD(Entry, VFAT_CLOSE_CONTEXT, CloseListEntry);
 
        /* One less */
        --VfatGlobalData->CloseCount;
        /* Reset its entry to detect concurrent deletions */
        InitializeListHead(&CloseContext->CloseListEntry);
        ExReleaseFastMutex(&VfatGlobalData->CloseMutex);
 
        /* Get the elements */
        Vcb = CloseContext->Vcb;
        pFcb = CloseContext->Fcb;
        ExAcquireResourceExclusiveLite(&Vcb->DirResource, TRUE);
        /* If it didn't got deleted in between */
        if (BooleanFlagOn(pFcb->Flags, FCB_DELAYED_CLOSE))
        {
            /* Close it! */
            DPRINT("Late closing: %wZ\n", &pFcb->PathNameU);
            ClearFlag(pFcb->Flags, FCB_DELAYED_CLOSE);
            pFcb->CloseContext = NULL;
            VfatCommonCloseFile(Vcb, pFcb);
            ConcurrentDeletion = FALSE;
        }
        else
        {
            /* Otherwise, mark not to delete it */
            ConcurrentDeletion = TRUE;
        }
        ExReleaseResourceLite(&Vcb->DirResource);
 
        /* If we were the fastest, delete the context */
        if (!ConcurrentDeletion)
        {
            ExFreeToPagedLookasideList(&VfatGlobalData->CloseContextLookasideList, CloseContext);
        }
 
        /* Lock again the list */
        ExAcquireFastMutex(&VfatGlobalData->CloseMutex);
    }
 
    /* We're done, bye! */
    VfatGlobalData->CloseWorkerRunning = FALSE;
    ExReleaseFastMutex(&VfatGlobalData->CloseMutex);
}
 
NTSTATUS
VfatPostCloseFile(
    PDEVICE_EXTENSION DeviceExt,
    PFILE_OBJECT FileObject)
{
    PVFAT_CLOSE_CONTEXT CloseContext;
 
    /* Allocate a work item */
    CloseContext = ExAllocateFromPagedLookasideList(&VfatGlobalData->CloseContextLookasideList);
    if (CloseContext == NULL)
    {
        return STATUS_INSUFFICIENT_RESOURCES;
    }
 
    /* Set relevant fields */
    CloseContext->Vcb = DeviceExt;
    CloseContext->Fcb = FileObject->FsContext;
    CloseContext->Fcb->CloseContext = CloseContext;
 
    /* Acquire the lock to insert in list */
    ExAcquireFastMutex(&VfatGlobalData->CloseMutex);
 
    /* One more element */
    InsertTailList(&VfatGlobalData->CloseListHead, &CloseContext->CloseListEntry);
    ++VfatGlobalData->CloseCount;
 
    /* If we have more than 16 items in list, and no worker thread
     * start a new one
     */
    if (VfatGlobalData->CloseCount > 16 && !VfatGlobalData->CloseWorkerRunning)
    {
        VfatGlobalData->CloseWorkerRunning = TRUE;
        IoQueueWorkItem(VfatGlobalData->CloseWorkItem, VfatCloseWorker, CriticalWorkQueue, NULL);
    }
 
    /* We're done */
    ExReleaseFastMutex(&VfatGlobalData->CloseMutex);
 
    return STATUS_SUCCESS;
}
 
/*
 * FUNCTION: Closes a file
 */
NTSTATUS
VfatCloseFile(
    PDEVICE_EXTENSION DeviceExt,
    PFILE_OBJECT FileObject)
{
    PVFATFCB pFcb;
    PVFATCCB pCcb;
    BOOLEAN IsVolume;
    NTSTATUS Status = STATUS_SUCCESS;
 
    DPRINT("VfatCloseFile(DeviceExt %p, FileObject %p)\n",
            DeviceExt, FileObject);
 
    /* FIXME : update entry in directory? */
    pCcb = (PVFATCCB) (FileObject->FsContext2);
    pFcb = (PVFATFCB) (FileObject->FsContext);
 
    if (pFcb == NULL)
    {
        return STATUS_SUCCESS;
    }
 
    IsVolume = BooleanFlagOn(pFcb->Flags, FCB_IS_VOLUME);
 
    if (pCcb)
    {
        vfatDestroyCCB(pCcb);
    }
 
    /* If we have to close immediately, or if delaying failed, close */
    if (VfatGlobalData->ShutdownStarted || !BooleanFlagOn(pFcb->Flags, FCB_DELAYED_CLOSE) ||
        !NT_SUCCESS(VfatPostCloseFile(DeviceExt, FileObject)))
    {
        VfatCommonCloseFile(DeviceExt, pFcb);
    }
 
    FileObject->FsContext2 = NULL;
    FileObject->FsContext = NULL;
    FileObject->SectionObjectPointer = NULL;
 
#ifdef ENABLE_SWAPOUT
    if (IsVolume && DeviceExt->OpenHandleCount == 0)
    {
        VfatCheckForDismount(DeviceExt, FALSE);
    }
#endif
 
    return Status;
}
 
/*
 * FUNCTION: Closes a file
 */
NTSTATUS
VfatClose(
    PVFAT_IRP_CONTEXT IrpContext)
{
    NTSTATUS Status;
 
    DPRINT("VfatClose(DeviceObject %p, Irp %p)\n", IrpContext->DeviceObject, IrpContext->Irp);
 
    if (IrpContext->DeviceObject == VfatGlobalData->DeviceObject)
    {
        DPRINT("Closing file system\n");
        IrpContext->Irp->IoStatus.Information = 0;
        return STATUS_SUCCESS;
    }
    if (!ExAcquireResourceExclusiveLite(&IrpContext->DeviceExt->DirResource, BooleanFlagOn(IrpContext->Flags, IRPCONTEXT_CANWAIT)))
    {
        return VfatMarkIrpContextForQueue(IrpContext);
    }
 
    Status = VfatCloseFile(IrpContext->DeviceExt, IrpContext->FileObject);
    ExReleaseResourceLite(&IrpContext->DeviceExt->DirResource);
 
    IrpContext->Irp->IoStatus.Information = 0;
 
    return Status;
}
 
/* EOF */