[lustre-devel] Using loff_t or u64 for PFL port

[James Simmons]

> On Oct 28, 2018, at 21:49, James Simmons <jsimmons at infradead.org> wrote:
> > 
> > 
> > While doing the PFL port I noticed a inconsistent use of loff_t and u64.
> > While in Greg's branch several patches landed to make the prototypes
> > match the function with changing any unmatching loff_t/u64 to use u64.
> > I don't know if using u64 solely as the proper solution. What is the
> > proper unit to use?
> 
> James, could you please clarify what part of the code you are referencing?

I see where the divergence happened. The linux client commit 

21aef7d9d6544 (staging/lustre: get rid of obd_* typedefs)

Changed the old obd_off to u64 while in the OpenSFS branch some were
changed to loff_t. A good example is 

int lov_stripe_offset(struct lov_stripe_md *lsm, int index,
		      loff_t lov_off, int stripeno, loff_t *obd_off);

For upstream client its:

int lov_stripe_offset(struct lov_stripe_md *lsm, u64 lov_off,
                      int stripeno, u64 *u64);

The big difference between the two is that loff_t can be a negative
value. I can compile a list of the difference so an audit cna be done.
Then we can go over what should be loff_t and what should be u64.