Re: [RFC PATCH V2] iomap: add support to track dirty state of sub pages

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, Aug 18, 2020 at 05:50:19PM +0100, Matthew Wilcox wrote:
> On Tue, Aug 18, 2020 at 09:12:29AM -0700, Darrick J. Wong wrote:
> > On Tue, Aug 18, 2020 at 04:53:05PM +0100, Matthew Wilcox wrote:
> > > It would be better to use the same wording as below:
> > > 
> > > > +	bitmap_zero(iop->state, PAGE_SIZE * 2 / SECTOR_SIZE);
> > 
> > ISTR there was some reason why '512' was hardcoded in here instead of
> > SECTOR_SIZE.  I /think/ it was so that iomap.h did not then have a hard
> > dependency on blkdev.h and everything else that requires...
> 
> That ship already sailed.  I over-trimmed this line:
> 
> -       bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
> 
> Looks like Christoph changed his mind sometime between that message
> and the first commit: 9dc55f1389f9569acf9659e58dd836a9c70df217

Aha, I think the complaint was about SECTOR_SIZE use in iomap.h, not the
fs/iomap/ code.  This patch doesn't touch the header.  I will stop
babbling and go back to reading it. ;)

--D

> My THP patches convert the bit array to be per-block rather than
> per-sector, so this is all going to go away soon ;-)
> 
> > https://lore.kernel.org/linux-xfs/20181215105155.GD1575@lst.de/