From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: axboe@kernel.dk, djwong@kernel.org, linux-block@vger.kernel.org
Subject: Re: [PATCH] loop: stop using vfs_iter_{read,write} for buffered I/O
Date: Tue, 15 Apr 2025 11:41:00 +0800 [thread overview]
Message-ID: <Z_3VTGpuLQ1BcqvG@fedora> (raw)
In-Reply-To: <20250409130940.3685677-1-hch@lst.de>
On Wed, Apr 09, 2025 at 03:09:40PM +0200, Christoph Hellwig wrote:
> vfs_iter_{read,write} always perform direct I/O when the file has the
> O_DIRECT flag set, which breaks disabling direct I/O using the
> LOOP_SET_STATUS / LOOP_SET_STATUS64 ioctls.
>
> This was recenly reported as a regression, but as far as I can tell
> was only uncovered by better checking for block sizes and has been
> around since the direct I/O support was added.
>
> Fix this by using the existing aio code that calls the raw read/write
> iter methods instead. Note that despite the comments there is no need
> for block drivers to ever call flush_dcache_page themselves, and the
> call is a left-over from prehistoric times.
>
> Fixes: ab1cb278bc70 ("block: loop: introduce ioctl command of LOOP_SET_DIRECT_IO")
> Reported-by: Darrick J. Wong <djwong@kernel.org>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Looks fine,
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Thanks,
Ming
next prev parent reply other threads:[~2025-04-15 3:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-09 13:09 [PATCH] loop: stop using vfs_iter_{read,write} for buffered I/O Christoph Hellwig
2025-04-09 13:44 ` Ming Lei
2025-04-10 7:34 ` Christoph Hellwig
2025-04-10 22:07 ` Darrick J. Wong
2025-04-15 3:33 ` Ming Lei
2025-04-15 3:41 ` Ming Lei [this message]
2025-04-16 0:47 ` Darrick J. Wong
2025-04-16 0:59 ` Jens Axboe
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