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	id 5E3296732A; Tue,  4 Aug 2026 16:04:45 +0200 (CEST)
Date: Tue, 4 Aug 2026 16:04:45 +0200
From: Christoph Hellwig <hch@lst.de>
To: Tal Zussman <tz2294@columbia.edu>
Cc: Jens Axboe <axboe@kernel.dk>,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	"Darrick J. Wong" <djwong@kernel.org>,
	Christoph Hellwig <hch@lst.de>, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, Sashiko <sashiko-bot@kernel.org>
Subject: Re: [PATCH 2/2] block: take i_rwsem for the direct I/O write
 fallback
Message-ID: <20260804140445.GB8894@lst.de>
References: <20260802-blkdev-fixes-v1-0-a82fc549fd74@columbia.edu> <20260802-blkdev-fixes-v1-2-a82fc549fd74@columbia.edu> <d30b6c9f-e479-4cca-8dfa-576d7562d2fc@columbia.edu>
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On Sun, Aug 02, 2026 at 08:11:41PM +0300, Tal Zussman wrote:
> >  	} else {
> >  		/*
> >  		 * Take i_rwsem and invalidate_lock to avoid racing with
> > 
> 
> I seem to have stumbled into a Sashiko rabbit hole of issues with IOCB_NOWAIT
> and IOCB_ATOMIC here... [1].
> I'll wait a day or two and send an update along with some additional fixes
> I've spotted.

I think IOCB_ATOMIC vs fallback to buffered I/O is a generally
unsolved issue.  I know ext4 just has a warning, but I'm not
sure how to avoid creating the problem in the first place.