Re: [PATCH] DAX: use proper length when the range is not aligned to PAGE_SIZE

[Liu Bo <bo.li.liu@oracle.com>]

On Fri, Nov 04, 2016 at 10:48:22PM +0100, Jan Kara wrote:
> On Fri 04-11-16 12:17:11, Liu Bo wrote:
> > Currently if we write to [2k, 6k] where pos is 2k and end is 6k,
> > get_block() will be called twice, but we can save one get_block
> > by sending two blocks together to get_block.
> > 
> > Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> 
> Thanks for the patch but this code is going to be ripped out soon (in the
> next merge window) in favor of iomap DAX implementation. So there's not
> much point in fixing this...

I see, thanks for the explanation.

Thanks,

-liubo
> 
> 								Honza
> 
> > ---
> >  fs/dax.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/dax.c b/fs/dax.c
> > index 53eb6a0..8d4bd5f 100644
> > --- a/fs/dax.c
> > +++ b/fs/dax.c
> > @@ -172,7 +172,7 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
> >  			long size;
> >  
> >  			if (pos == bh_max) {
> > -				bh->b_size = PAGE_ALIGN(end - pos);
> > +				bh->b_size = PAGE_ALIGN(end - (pos - first));
> >  				bh->b_state = 0;
> >  				rc = get_block(inode, block, bh, rw == WRITE);
> >  				if (rc)
> > -- 
> > 2.5.5
> > 
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR