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Date:   Wed, 20 Apr 2022 11:12:00 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH] f2fs: use flush command instead of FUA for zoned device
Message-ID: <YmBM8KEZ9JttevxH@google.com>
References: <20220419215703.1271395-1-jaegeuk@kernel.org>
 <Yl+XIjiuFRN9Pzxv@infradead.org>
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On 04/19, Christoph Hellwig wrote:
> On Tue, Apr 19, 2022 at 02:57:03PM -0700, Jaegeuk Kim wrote:
> > The block layer for zoned disk can reorder the FUA'ed IOs. Let's use flush
> > command to keep the write order.
> 
> The block layer can reorder all commands.  Given that FUA only affects
> the command itself that should not matter.  What is this trying to fix?

Not for zoned disk, as I mentioned. The mq-deadline serializes write commands
but I got an reordered command, if there's a FUA|PREFLUSH command, which emits
EIO by the disk.