[Cluster-devel] [PATCH] libgfs2: Import gfs2_ondisk.h

[Andrew Price <anprice@redhat.com>]

On 09/04/2019 13:03, Christoph Hellwig wrote:
> On Tue, Apr 09, 2019 at 10:41:53AM +0100, Andrew Price wrote:
>> Give gfs2-utils its own copy of gfs2_ondisk.h which uses userspace
>> types. This allows us to always support the latest ondisk structures and
>> obsoletes a lot of #ifdef GFS2_HAS_<FEATURE> blocks and configure.ac
>> checks.
>>
>> gfs2_ondisk.h was changed simply by search-and-replace of the kernel int
>> types with the uintN_t, i.e.:
>>
>> :%s/__u\(8\|16\|32\|64\)/uint\1_t/g
>> :%s/__be\(64\|32\|16\|8\)/uint\1_t/g
>>
>> and the linux/types.h include replaced with stdint.h
> 
> Why?

Because I'd like to be able to build gfs2-utils on FreeBSD one day. Plus 
we get the handy stuff in inttypes.h to use, Linux doesn't have that.

> At least the be types give you really useful type checking with
> sparse, which can be trivially wired up in userspace as well.

If you mean the bitwise annotations that only sparse checks, we're 
fairly safe in gfs2-utils in that anything represented by a struct is 
going to have been parsed through one of the libgfs2/ondisk.c functions 
so will be the right endianness. I run sparse over this code very rarely 
anyway.

> Also
> keeping the file 1:1 the same is going to make your life much easier
> in the future..

It's really no difficulty to run the above substitutions the next time 
the file changes, but gfs2_ondisk.h changes once in a blue moon anyway 
so the maintenance overhead is going to be tiny.

Andy