linux-ext4 - Re: [PATCH 03/10] ext4: Convert mpage_release_unused_pages() to use filemap_get

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Message-ID: <YqFvGgKTyGPxStkx@infradead.org>
Date:   Wed, 8 Jun 2022 20:55:06 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     Christoph Hellwig <hch@...radead.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
        linux-mm@...ck.org, linux-nilfs@...r.kernel.org
Subject: Re: [PATCH 03/10] ext4: Convert mpage_release_unused_pages() to use
 filemap_get_folios()

On Wed, Jun 08, 2022 at 05:02:40PM +0100, Matthew Wilcox wrote:
> On Wed, Jun 08, 2022 at 01:02:22AM -0700, Christoph Hellwig wrote:
> > On Sun, Jun 05, 2022 at 08:38:47PM +0100, Matthew Wilcox (Oracle) wrote:
> > > If the folio is large, it may overlap the beginning or end of the
> > > unused range.  If it does, we need to avoid invalidating it.
> > 
> > It's never going to be larger for ext4, is it?  But either way,
> > those precautions looks fine.
> 
> I don't want to say "never".  Today, it's not, but if ext4 ever does
> gain support for large folios, then this is a precaution it will need
> to take.  I'm trying not to leave traps when I do conversions.

FYI, this wasn't an objection to the patch, just a hint that the commit
log could spell this out a bit better.