Re: [PATCH 06/14] Pramfs: Include files

From: Arnd Bergmann
Date: Sat Jun 13 2009 - 19:00:27 EST


On Saturday 13 June 2009, Sam Ravnborg wrote:
> > + union {
> > + struct {
> > + /*
> > + * ptr to row block of 2D block pointer array,
> > + * file block #'s 0 to (blocksize/4)^2 - 1.
> > + */
> > + off_t row_block;
>
> It is my understanding that we shall use: __kernel_off_t
> in exported headers.

That is a correct understanding in general, however this case is
different, because it describes an on-disk data structure,
not a kernel to user space interface. Here, __kernel_off_t is just
as wrong as off_t, because it will differ between 32 and 64 bit
architectures, making the fs layout incompatible. I'd suggest
simply defining this as __u64.

Moreover, file system layout should be described in terms of
big-endian or little-endian types (e.g. __be64 or __le64),
together with the right accessor functions.

Arnd <><
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