Re: [PATCH 11/13] xfs: expose block size in stat

[Pankaj Raghav (Samsung)]

On Mon, Feb 26, 2024 at 11:44:16PM +1100, Dave Chinner wrote:
> On Mon, Feb 26, 2024 at 10:49:34AM +0100, Pankaj Raghav (Samsung) wrote:
> > From: Dave Chinner <dchinner@xxxxxxxxxx>
> > 
> > For block size larger than page size, the unit of efficient IO is
> > the block size, not the page size. Leaving stat() to report
> > PAGE_SIZE as the block size causes test programs like fsx to issue
> > illegal ranges for operations that require block size alignment
> > (e.g. fallocate() insert range). Hence update the preferred IO size
> > to reflect the block size in this case.
> > 
> > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> > dd2d535e3fb29d ("xfs: cleanup calculating the stat optimal I/O size")]
> > Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> 
> Something screwed up there, and you haven't put your own SOB on
> this.
Oops. I will add it.

> 
> > ---
> >  fs/xfs/xfs_iops.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> > index a0d77f5f512e..1b4edfad464f 100644
> > --- a/fs/xfs/xfs_iops.c
> > +++ b/fs/xfs/xfs_iops.c
> > @@ -543,7 +543,7 @@ xfs_stat_blksize(
> >  			return 1U << mp->m_allocsize_log;
> >  	}
> >  
> > -	return PAGE_SIZE;
> > +	return max_t(unsigned long, PAGE_SIZE, mp->m_sb.sb_blocksize);
> >  }
> 
> This function returns a uint32_t, same type as
> mp->m_sb.sb_blocksize. The comparision should use uint32_t casts,
> not unsigned long.
> 
Yeah. Something like this instead of using unsigned long:

return max_t(uint32_t, PAGE_SIZE, mp->m_sb.sb_blocksize);

> ALso, this bears no resemblence to the original patch I wrote back in
> 2018. Please remove my SOB from it - you can state that "this change
> is based on a patch originally from Dave Chinner" to credit the
> history of it, but it's certainly not the patch I wrote 6 years ago
> and so my SOB does not belong on it.
Ok.

> 
> -Dave.
> -- 
> Dave Chinner
> david@xxxxxxxxxxxxx