彻底刷新文件系统的缓存

最新推荐文章于 2019-11-20 11:02:24 发布

转载最新推荐文章于 2019-11-20 11:02:24 发布 · 3.3k 阅读

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本文详细介绍了如何使用Windows内核API彻底刷新文件系统的缓存，包括释放资源、刷新缓存、关闭缓存等关键步骤，对于提高系统性能具有重要意义。

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彻底刷新文件系统的缓存 [转载]

void PurgeFileSystemBuffers(PFILE_OBJECT FileObject)
{
KeEnterCriticalRegion();
if(ExAcquireResourceExclusiveLite(((PFSRTL_COMMON_FCB_HEADER)FileObject->FsContext)->Resource,FALSE))
{
    if(FileObject->SectionObjectPointer)
    {
        IoSetTopLevelIrp((PIRP)FSRTL_FSP_TOP_LEVEL_IRP );
        CcFlushCache( FileObject->SectionObjectPointer,NULL, 0,NULL);
        if(FileObject->SectionObjectPointer->ImageSectionObject)
        {
            MmFlushImageSection(
                FileObject->SectionObjectPointer,
                MmFlushForWrite//MmFlushForDelete//

                );
        }
        if(FileObject->SectionObjectPointer->DataSectionObject)
        {
            CcPurgeCacheSection( FileObject->SectionObjectPointer,
                NULL,
                0,
                TRUE);//为TRUE，会强迫所有的FileObject重新初始化Cache

        }
        if(FileObject->PrivateCacheMap)
        {
            CcUninitializeCacheMap(FileObject,NULL,NULL);;
        }
        if(FileObject->SectionObjectPointer->DataSectionObject)
        {
            //Interval.QuadPart = DELAY_ONE_MILLISECOND * 500;//500ms

            //KeDelayExecutionThread(KernelMode, FALSE, &Interval);

            MmForceSectionClosed( FileObject->SectionObjectPointer,
                TRUE//改为TRUE,彻底刷新缓存!!!

                );
        }
        IoSetTopLevelIrp(NULL);
    }
    ExReleaseResourceLite(((PFSRTL_COMMON_FCB_HEADER)FileObject->FsContext)->Resource );
}
KeLeaveCriticalRegion();
}

参考2：

void ManageFileCache(PFILE_OBJECT pFileObject)
   {

      PFSRTL_COMMON_FCB_HEADER pFcb;
      LARGE_INTEGER liInterval;
      //BOOLEAN bNeedReleaseResource = FALSE;

      //BOOLEAN bNeedReleasePagingIoResource = FALSE;

      KIRQL irql;
      BOOLEAN bLockedResource=FALSE;
      BOOLEAN bLockedPagingIoResource=FALSE;
      BOOLEAN bReleaseResource=FALSE;
      BOOLEAN bReleasePagingIoResource=FALSE;



      pFcb =(PFSRTL_COMMON_FCB_HEADER)pFileObject->FsContext;
      if(pFcb ==NULL)
      {
          return;
      }

      irql = KeGetCurrentIrql();
      if(irql >= DISPATCH_LEVEL)
      {
          return;
      }
      liInterval.QuadPart =-1 *(LONGLONG)50;

    //KeEnterCriticalRegion();

      bLockedPagingIoResource = ExIsResourceAcquiredExclusiveLite(pFcb->PagingIoResource);
      bLockedResource=ExIsResourceAcquiredExclusiveLite(pFcb->Resource);

      if(!bLockedPagingIoResource)
         bReleasePagingIoResource=TRUE;

      if(!bLockedResource)
         bReleaseResource=TRUE;

      while(!bLockedPagingIoResource ||!bLockedResource)
      {
      if(!bLockedResource)
         {
             if(ExAcquireResourceExclusiveLite(pFcb->Resource,FALSE)==TRUE)
               bLockedResource=TRUE;
           else
               goto clear;

         }
         if(!bLockedPagingIoResource)
         {
             if(ExAcquireResourceExclusiveLite(pFcb->PagingIoResource,FALSE)==TRUE)
               bLockedPagingIoResource=TRUE;
           else
               goto clear;

         }

       if(bLockedPagingIoResource && bLockedResource)
           break;
       clear:
           if(bLockedPagingIoResource)
           {
               ExReleaseResourceLite(pFcb->PagingIoResource);
               bLockedPagingIoResource =FALSE;
           }
        if(bLockedResource)
        {
            ExReleaseResourceLite(pFcb->Resource);
               bLockedResource=FALSE;
          }
           KeLeaveCriticalRegion();
           if(irql == PASSIVE_LEVEL)
          {
              KeDelayExecutionThread(KernelMode,FALSE,&liInterval);
          }
          else
          {
              KEVENT waitEvent;
              KeInitializeEvent(&waitEvent, NotificationEvent,FALSE);
              KeWaitForSingleObject(&waitEvent, Executive, KernelMode,FALSE,&liInterval);
             }
           KeEnterCriticalRegion();
       }

      //加锁完毕

      if(pFileObject->SectionObjectPointer !=NULL)
         {
            IO_STATUS_BLOCK ioStatus;
          CcFlushCache(pFileObject->SectionObjectPointer,NULL, 0,&ioStatus);

          if(pFileObject->SectionObjectPointer->ImageSectionObject !=NULL)
             MmFlushImageSection(pFileObject->SectionObjectPointer, MmFlushForWrite);//MmFlushForDelete


          if(pFileObject->SectionObjectPointer->DataSectionObject !=NULL)
             CcPurgeCacheSection(pFileObject->SectionObjectPointer ,NULL, 0,FALSE);
       }

      if(bReleasePagingIoResource)
         {
           ExReleaseResourceLite(pFcb->PagingIoResource);
           bLockedPagingIoResource =FALSE;
      }
      if(bReleaseResource)
      {
        ExReleaseResourceLite(pFcb->Resource);
           bLockedResource=FALSE;
       }

      KeLeaveCriticalRegion();

   }