Received-SPF: pass (google.com: domain of linux-ext4+bounces-82-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
Date: Wed, 22 Nov 2023 05:11:18 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>,
	linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [RFC 2/3] ext2: Convert ext2 regular file buffered I/O to use
 iomap
Message-ID: <ZV399sCMq+p57Yh3@infradead.org>
References: <cover.1700506526.git.ritesh.list@gmail.com>
 <f5e84d3a63de30def2f3800f534d14389f6ba137.1700506526.git.ritesh.list@gmail.com>
 <20231122122946.wg3jqvem6fkg3tgw@quack3>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231122122946.wg3jqvem6fkg3tgw@quack3>

On Wed, Nov 22, 2023 at 01:29:46PM +0100, Jan Kara wrote:
> writeback bit set. XFS plays the revalidation sequence counter games
> because of this so we'd have to do something similar for ext2. Not that I'd
> care as much about ext2 writeback performance but it should not be that
> hard and we'll definitely need some similar solution for ext4 anyway. Can
> you give that a try (as a followup "performance improvement" patch).

Darrick has mentioned that he is looking into lifting more of the
validation sequence counter validation into iomap.

In the meantime I have a series here that at least maps multiple blocks
inside a folio in a single go, which might be worth trying with ext2 as
well:

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/iomap-map-multiple-blocks