[ros-kernel] RE: Re: Kernel Bug

[Mark W. <ma...@np...>]

If you have a diff, you can just run patch.  No need to find the line as
patch can cope (to a certain extent) with lines shifting about, which may
have changed if the developer's version of the file is different from the
patch submitters.  It's also easier for the submitter as they can be sure
that they haven't missed a change, plus they don't have to go and find line
numbers themselves.  I don't think that anyone is going to reject a
submission made in this way, but it's worht pointing out that for the future
this is a better way to submit patches.  For generating diffs, I use the GNU
diff program included with cygwin (www.cygwin.com).

Cheers,

Mark

> -----Original Message-----
> From: Guido de Jong [mailto:gui...@ch...]
> Sent: 25 September 2001 20:38
> To: ros...@re...
> Subject: [ros-kernel] Re: Kernel Bug
>
>
> Now I don't too much about ReactOS programming, but IMHO Jack was
> quite plain
> about it:
>
> There is this function called MiReadPage() which you can find in
> mm/section.c, lines 252-337. This function does a call to IOReadPage() in
> line 290, if the page in cache is not up-to-date. According to
> Jack it is not
> an error if this function returns STATUS_END_OF_FILE, which
> apparently is not
> equal to NT_SUCCESS(). So he added
>
> 	&& Status != STATUS_END_OF_FILE
>
> to line 295. IMHO it will have been even better if you add
>
> 	&& (Status != STATUS_END_OF_FILE)
>
> in stead. Do you really need a diff for this?
>
> See added line numbers below.
>
> - Guido
>
>
> On Tuesday 25 September 2001 20:27, Jason Filby wrote:
> > Has anyone tested/updated the tree with this update and the latest
> > one from Jack?
> >
> > Jack: it seems that most developers prefer that you send them the
> > "diffs".. but I don't think I have diff installed?..
> >
> > - Jason
> >
> > --- "Jack (Butch) Griffin" <bu...@qw...> wrote:
> > > I have been playing with the ReactOS operating system and trying to
> > > get a
> > > console mode app written in vistual C++ to run.  The app is your
> > > basic hello
> > > world application.  I did not really expect that the complete
> > > infra-structure was in place for this to run, but I figured it
> > > would point
> > > out what was missing and give me a starting point for beginning to
> > > learn
> > > about the design of this OS.
> > >
> > > Anyway I have found a problem and do not know who should get the
> > > updated
> > > code.  The problem is in MiReadPage() and the updated code is
> > > below.  The
> > > only change is that STATUS_END_OF_FILE is a legimate return from
> > > IoPageRead().  It does not mean an error occurred, just that the
> > > file did
> > > not contain enough data to fill the page.  Function that call
> > > MiReadPage()
> > > assume that the data read are OK if the return value is
> > > STATUS_END_OF_FILE,
> > > so the update of the Page pointer must be done in this case.
> > >
> > > Thanks
> > > Jack Griffin
>
> 252: NTSTATUS
> MiReadPage(PMEMORY_AREA MemoryArea,
> 	   PLARGE_INTEGER Offset,
> 	   PVOID* Page)
> {
>   IO_STATUS_BLOCK IoStatus;
>   PFILE_OBJECT FileObject;
>   PMDL Mdl;
>   NTSTATUS Status;
>   PREACTOS_COMMON_FCB_HEADER Fcb;
>
>   FileObject = MemoryArea->Data.SectionData.Section->FileObject;
>   Fcb = (PREACTOS_COMMON_FCB_HEADER)FileObject->FsContext;
>
>   if (FileObject->Flags & FO_DIRECT_CACHE_PAGING_READ &&
>       (Offset->QuadPart % PAGESIZE) == 0)
>     {
>       ULONG BaseOffset;
>       PVOID BaseAddress;
>       BOOLEAN UptoDate;
>       PCACHE_SEGMENT CacheSeg;
>       LARGE_INTEGER SegOffset;
>       PHYSICAL_ADDRESS Addr;
>       Status = CcRosGetCacheSegment(Fcb->Bcb,
> 				 (ULONG)Offset->QuadPart,
> 				 &BaseOffset,
> 				 &BaseAddress,
> 				 &UptoDate,
> 				 &CacheSeg);
>       if (!NT_SUCCESS(Status))
> 	{
> 	  return(Status);
> 	}
>       if (!UptoDate)
> 	{
> 	  Mdl = MmCreateMdl(NULL, BaseAddress, Fcb->Bcb->CacheSegmentSize);
> 	  MmBuildMdlForNonPagedPool(Mdl);
> 	  SegOffset.QuadPart = BaseOffset;
> 290:	  Status = IoPageRead(FileObject,
> 			      Mdl,
> 			      &SegOffset,
> 			      &IoStatus,
> 			      TRUE);
> 295:	  if (!NT_SUCCESS(Status) && Status != STATUS_END_OF_FILE)
> 	    {
> 	      CcRosReleaseCacheSegment(Fcb->Bcb, CacheSeg, FALSE);
> 	      return(Status);
> 	    }
> 	}
>       Addr = MmGetPhysicalAddress(BaseAddress +
> 				  Offset->QuadPart - BaseOffset);
>       (*Page) = (PVOID)(ULONG)Addr.QuadPart;
>       MmReferencePage((*Page));
>
>       CcRosReleaseCacheSegment(Fcb->Bcb, CacheSeg, TRUE);
>       return(STATUS_SUCCESS);
>     }
>   else
>     {
>       /*
>        * Allocate a page, this is rather complicated by the possibility
>        * we might have to move other things out of memory
>        */
>       (*Page) = MmAllocPage(0);
>       while ((*Page) == NULL)
> 	{
> 	  MmWaitForFreePages();
> 	  (*Page) = MmAllocPage(0);
> 	}
>
>       /*
>        * Create an mdl to hold the page we are going to read data into.
>        */
>       Mdl = MmCreateMdl(NULL, NULL, PAGESIZE);
>       MmBuildMdlFromPages(Mdl, (PULONG)Page);
>       /*
>        * Call the FSD to read the page
>        */
>       Status = IoPageRead(FileObject,
> 			  Mdl,
> 			  Offset,
> 			  &IoStatus,
> 			  FALSE);
>       return(Status);
>     }
> 337: }
>
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