[OpenAFS-devel] afs_buffer.c:DRead()

[Nickolai Zeldovich]

>     tfile = afs_CFileOpen(fid[0]);
>     sizep = (afs_int32 *)tfile;
>     if (page * AFS_BUFFER_PAGESIZE >= *sizep) {
>         give_up...
> 
> Since tfile is really a struct osi_file *, this can't possibly work except
> by accident.

This does seem very backwards, but as far as I can tell, it actually does
work.  As afs_osi.h says:

  struct osi_file {
      afs_int32 size;             /* file size in bytes XXX Must be first field XXX */
      ...
  }

so sizep points at osi_file.size, and dereferencing it should infact give
you the size value.  I'm really unclear on why they decided to manually
decode struct fields, instead of using, oh, say, tfile->size.  Oh, I guess
tfile is void*; but casting it to osi_file seems like a much better way
to do it than this..

-- kolya