Re: [RFC PATCH v3 07/26] iomap: don't increase i_size if it's not a write operation

[Dave Chinner]

On Sat, Feb 17, 2024 at 04:55:51PM +0800, Zhang Yi wrote:
> On 2024/2/13 13:46, Christoph Hellwig wrote:
> > Wouldn't it make more sense to just move the size manipulation to the
> > write-only code?  An untested version of that is below.  With this
> 
> Sorry for the late reply and thanks for your suggestion, The reason why
> I introduced this new helper iomap_write_end_simple() is I don't want to
> open code __iomap_put_folio() in each caller since corresponding to
> iomap_write_begin(), it's the responsibility for iomap_write_end_*() to
> put and unlock folio, so I'd like to keep it in iomap_write_end_*().

Just because we currently put the folio in iomap_write_end_*(), it
doesn't mean we must always do it that way.

> But I don't feel strongly about it, it's also fine by me to just move
> the size manipulation to the write-only code if you think it's better.

I agree with Christoph that it's better to move the i_size update
into iomap_write_iter() than it is to implement a separate write_end
function that does not update the i_size. The iter functions already
do work directly on the folio that iomap_write_begin() returns, so
having them drop the folio when everything is done isn't a huge
deal...

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx