Received-SPF: pass (google.com: domain of linux-kernel+bounces-100256-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
Date: Tue, 12 Mar 2024 05:24:00 -0700
From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Zhang Yi <yi.zhang@huaweicloud.com>, linux-xfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	hch@infradead.org, brauner@kernel.org, david@fromorbit.com,
	tytso@mit.edu, jack@suse.cz, yi.zhang@huawei.com,
	chengzhihao1@huawei.com, yukuai3@huawei.com
Subject: Re: [PATCH 4/4] iomap: cleanup iomap_write_iter()
Message-ID: <ZfBJYG5OHgLGewHv@infradead.org>
References: <20240311122255.2637311-1-yi.zhang@huaweicloud.com>
 <20240311122255.2637311-5-yi.zhang@huaweicloud.com>
 <20240311160739.GV1927156@frogsfrogsfrogs>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240311160739.GV1927156@frogsfrogsfrogs>

On Mon, Mar 11, 2024 at 09:07:39AM -0700, Darrick J. Wong wrote:
> If at some point iomap_write_end actually starts returning partial write
> completions (e.g. you wrote 250 bytes, but for some reason the pagecache
> only acknowledges 100 bytes were written) then this code no longer
> reverts the iter or truncates posteof pagecache correctly...

I don't think it makes sense to return a partial write from
iomap_write_end.  But to make that clear it really should not return
a byte count by a boolean.  I've been wanting to make that cleanup
for a while, but it would reach all the way into buffer.c.