On Jan 4, 2014, at 4:54 PM, Hitoshi Mitake wrote:
> On Sat, Jan 4, 2014 at 11:52 PM, Vyacheslav Dubeyko <slava@xxxxxxxxxxx> wrote:
>>
>> On Jan 4, 2014, at 4:29 PM, Hitoshi Mitake wrote:
>>
>>> Current nilfs_check_ondisk_sizes() checks sizes of important structs
>>> at run time. The checking should be done at build time. This patch
>>> adds a new macro, BUILD_BUG_ON(), for this purpose. It is similar to
>>> static_assert() of C++11. If an argument is true, the macro causes a
>>> bulid error.
>>>
>>> Below is an example of BUILD_BUG_ON(). When the checked conditions are
>>> true like below:
>>>
>>> /* intentional change for testing BUILD_BUG_ON() */
>>>
>>> static __attribute__((used)) void nilfs_check_ondisk_sizes(void)
>>> {
>>> BUILD_BUG_ON(sizeof(struct nilfs_inode) > NILFS_MIN_BLOCKSIZE);
>>
>> So, why do we need to have function for the case of checking on compilation
>> phase?
>
> Just for excluding the checking from other part of code and improve readability.
>
I think that we can have only macro instead of the function nilfs_check_ondisk_sizes().
And this macros can be placed in the begin of main() call. I think that it will be enough
for the compilation phase check.
>>
>> I suppose that we need to have some run-time check anyway. Your approach
>> is correct for the current state of the code. But I feel a necessity in run-time check
>> anyway. Maybe it looks like a paranoia. :) Maybe it needs to extend checking
>> in this place.
>
> Do you mean both of the build time check and the run time check? If
> so, I agree with your opinion. I'll send v2 based on this policy.
>
I mean that block size can be different during volume creation and maybe
it makes sense to extend a block size related checking for run-time phase.
That's all. But right now I haven't any concrete suggestions.
Thanks,
Vyacheslav Dubeyko.
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