Re: [PATCH] f2fs: adjust the way of calculating nat block

[Fan Li <fanofcode.li@samsung.com>]

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Thursday, March 09, 2017 5:56 AM
> To: Fan Li
> Cc: linux-f2fs-devel@lists.sourceforge.net
> Subject: Re: [f2fs-dev] [PATCH] f2fs: adjust the way of calculating nat block
> 
> On 03/08, Fan Li wrote:
> > use a slightly simpler expression to calculate nat block with nid.
> >
> > Signed-off-by: Fan Li <fanofcode.li@samsung.com>
> > ---
> >  fs/f2fs/node.h | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h index 2f9603f..f9fb5b8
> > 100644
> > --- a/fs/f2fs/node.h
> > +++ b/fs/f2fs/node.h
> > @@ -200,13 +200,11 @@ static inline pgoff_t current_nat_addr(struct f2fs_sb_info *sbi, nid_t start)
> >         struct f2fs_nm_info *nm_i = NM_I(sbi);
> >         pgoff_t block_off;
> >         pgoff_t block_addr;
> > -       int seg_off;
> >
> >         block_off = NAT_BLOCK_OFFSET(start);
> > -       seg_off = block_off >> sbi->log_blocks_per_seg;
> >
> >         block_addr = (pgoff_t)(nm_i->nat_blkaddr +
> > -               (seg_off << sbi->log_blocks_per_seg << 1) +
> > +               (block_off << 1) -
> 
> NAK. This breaks the behavior.

OK, I'm guessing by "breaks the behavior", you mean make the code hard to understand?
I was concerned the same thing, but with the context, I think most people will be able to
 see right through it, and it saves some calculation, makes code as simple as possible, I
just think maybe it's worthy.


> 
> Thanks,
> 
> >                 (block_off & (sbi->blocks_per_seg - 1)));
> >
> >         if (f2fs_test_bit(block_off, nm_i->nat_bitmap))
> > --
> > 2.7.4



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