Re: [PATCH v17 04/10] fs/ntfs3: Add file operations and implementation

[Matthew Wilcox]

On Sun, Jan 03, 2021 at 11:57:32PM +0200, Kari Argillander wrote:
> > +		/*
> > +		 * mirror of len, but signed, because run_packed_size()
> > +		 * works with signed int only
> > +		 */
> > +		len64 = len;
> > +
> > +		/* how much bytes is packed len64 */
> > +		size_size = run_packed_size(&len64);
> 
> Does (s64 *)&len work just fine?

No.  run_packed_size() is going to load/store eight bytes to/from that
pointer.  You can't just cast a pointer to a different size and expect
it to work (it might happen to work, particularly on little-endian,
but big-endian is going to get completely the wrong value).