Re: [RFC][PATCH] Set JBD2_FEATURE_INCOMPAT_64BIT on filesystems larger than 32-bit blocks (take 2).

["Jose R. Santos" <jrs@us.ibm.com>]

On Tue, 05 Jun 2007 16:03:44 +0200
Laurent Vivier <Laurent.Vivier@bull.net> wrote:
> Jose R. Santos wrote:
> > Hi Laurent,
> > 
> > In this particular case though, the value of s_blocks_count_hi should not be
> > uses on its own.  The correct way would be to use ext4_blocks_count() which
> > already does the endian conversion.  If you think the code could confuse
> > people as to how to access the data in s_blocks_count_hi, wouldn't hiding it
> > through the use of a macro make more sense than doing an unnecessary endian
> > conversion?
> > 
> 
> Yes, I think the code could confuse people, but I don't think defining "Yet
> Another Macro" is a good choice (IMHO).
> 
> I think we can resolve this (non-)issue by two ways:
> - using le32_to_cpu() (but I agree it does an unnecessary endian conversion on
> big-endian systems)

I just think that adding extra instructions for the sake of slightly
better code readability is wrong, especially when the value
s_blocks_count_hi should not be used on its own.

> - put a comment on the line (but are we allowed to put comments in kernel source
> code... ;-) )

One advantage of a macro here is that we would make the code more
explicit and should be able to eliminate the need for those 4 lines of
comments that this patch adds.

> Regards
> Laurent


-JRS