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Date: Thu, 4 Jan 2024 22:08:42 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
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Subject: Re: [PATCH RFC v3 for-6.8/block 02/17] xen/blkback: use bdev api in
 xen_update_blkif_status()
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 <20231221085712.1766333-3-yukuai1@huaweicloud.com>
 <20240104110631.3vspsvxbbvcpdqdu@quack3>
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On Thu, Jan 04, 2024 at 12:06:31PM +0100, Jan Kara wrote:
> This function uses invalidate_inode_pages2() while invalidate_bdev() ends
> up using mapping_try_invalidate() and there are subtle behavioral
> differences between these two (for example invalidate_inode_pages2() tries
> to clean dirty pages using the ->launder_folio method). So I think you'll
> need helper like invalidate_bdev2() for this.

That assues that the existing code actually does this intentionally,
which seems doubtful.  But the change in behavior does not to be
documented and explained.