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Date: Wed, 28 Jan 2026 04:47:01 +0100
From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Carlos Maiolino <cem@kernel.org>,
	Hans Holmberg <hans.holmberg@wdc.com>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 07/10] xfs: don't mark all discard issued by zoned GC
 as sync
Message-ID: <20260128034701.GD30989@lst.de>
References: <20260127160619.330250-1-hch@lst.de> <20260127160619.330250-8-hch@lst.de> <20260128013818.GG5945@frogsfrogsfrogs>
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On Tue, Jan 27, 2026 at 05:38:18PM -0800, Darrick J. Wong wrote:
> On Tue, Jan 27, 2026 at 05:05:47PM +0100, Christoph Hellwig wrote:
> > Discard are not usually sync when issued from zoned garbage collection,
> > so drop the REQ_SYNC flag.
> 
> Cc: <stable@vger.kernel.org> # v6.15
> 
> > Fixes: 080d01c41d44 ("xfs: implement zoned garbage collection")
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> What does REQ_SYNC even mean for a discard, anyway?

It expedites a few things in the block submission path basically.
And deep magic in the I/O schedulers, but I'm not sure if that
even applies to discard.