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Date: Mon, 14 Jul 2025 15:30:14 +0200
From: Christoph Hellwig <hch@lst.de>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Christoph Hellwig <hch@lst.de>, John Garry <john.g.garry@oracle.com>,
	"Darrick J. Wong" <djwong@kernel.org>,
	linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-block@vger.kernel.org, linux-nvme@lists.infradead.org
Subject: Re: Do we need an opt-in for file systems use of hw atomic writes?
Message-ID: <20250714133014.GA10090@lst.de>
References: <20250714131713.GA8742@lst.de> <20250714132407.GC41071@mit.edu>
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On Mon, Jul 14, 2025 at 09:24:07AM -0400, Theodore Ts'o wrote:
> > Is is just me, or would it be a good idea to require an explicit
> > opt-in to user hardware atomics?
> 
> How common do we think broken atomics implementations; is this
> something that we could solve using a blacklist of broken devices?

I don't know.  But cheap consumer SSDs can basically exhibit any
brokenness you can imagine.  And claiming to support atomics basically
just means filling out a single field in identify with a non-zero
value.  So my hopes of only seeing it in a few devices is low,
moreover we will only notice it was broken when people lost data.