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From: Christoph Hellwig <hch@infradead.org>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: Christoph Hellwig <hch@infradead.org>, Qu Wenruo <wqu@suse.com>,
	linux-fsdevel@vger.kernel.org,
	linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: About using on-stack fsdata pointer for write_begin() and write_end() callbacks
Date: Mon, 11 Nov 2024 22:06:25 -0800	[thread overview]
Message-ID: <ZzLwYZqwf7k5GlRV@infradead.org> (raw)
In-Reply-To: <03f86d46-0de3-4c7b-901f-1ae16b554186@gmx.com>

On Tue, Nov 12, 2024 at 04:33:56PM +1030, Qu Wenruo wrote:
> IIRC it's related to the get_user_page() shenanigans but not 100% sure.

While there might be a few stragglers left, everyone should be using
pin_user_pages when manipulating page contents.  The long tolerated
just pin and mark dirty is officially a bug now.

> I'm talking about the iomap_set_range_dirty() call inside
> iomap_writepage_map(), for the "if (i_blocks_per_folio() > 1)" branch.

That does not set the page dirty.  It propagatates the per-folio
dirty state into the per-block dirty bitmap allocated in the line
above.


  reply	other threads:[~2024-11-12  6:06 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-11  4:27 About using on-stack fsdata pointer for write_begin() and write_end() callbacks Qu Wenruo
2024-11-11  5:52 ` Christoph Hellwig
2024-11-11  7:36   ` Qu Wenruo
2024-11-12  5:05     ` Christoph Hellwig
2024-11-12  5:31       ` Qu Wenruo
2024-11-12  5:41         ` Christoph Hellwig
2024-11-12  6:03           ` Qu Wenruo
2024-11-12  6:06             ` Christoph Hellwig [this message]
2024-11-12  6:13               ` Qu Wenruo

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