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Date:   Thu, 18 May 2023 06:23:44 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Brian Foster <bfoster@redhat.com>
Cc:     Ritesh Harjani <ritesh.list@gmail.com>, linux-xfs@vger.kernel.org,
        linux-fsdevel@vger.kernel.org,
        Matthew Wilcox <willy@infradead.org>,
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        Ojaswin Mujoo <ojaswin@linux.ibm.com>,
        Disha Goel <disgoel@linux.ibm.com>,
        Aravinda Herle <araherle@in.ibm.com>
Subject: Re: [RFCv5 5/5] iomap: Add per-block dirty state tracking to improve
 performance
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On Wed, May 17, 2023 at 02:48:12PM -0400, Brian Foster wrote:
> But I also wonder.. if we can skip the iop alloc on full folio buffered
> overwrites, isn't that also true of mapped writes to folios that don't
> already have an iop?

Yes.

> I.e., I think what I was trying to do in the
> previous diff was actually something like this:
> 
> bool iomap_dirty_folio(struct address_space *mapping, struct folio *folio)
> {
>         iop_set_range_dirty(mapping->host, folio, 0, folio_size(folio));
>         return filemap_dirty_folio(mapping, folio);
> }
> 
> ... which would only dirty the full iop if it already exists. Thoughts?

That does sound pretty good to me, and I can't think of any obvious
pitfall.