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Date:   Wed, 19 Apr 2023 06:30:44 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Bart Van Assche <bvanassche@acm.org>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Ming Lei <ming.lei@redhat.com>
Subject: Re: [PATCH v2 06/11] block: mq-deadline: Disable head insertion
 for zoned writes
Message-ID: <20230419043044.GC25329@lst.de>
References: <20230418224002.1195163-1-bvanassche@acm.org> <20230418224002.1195163-7-bvanassche@acm.org>
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On Tue, Apr 18, 2023 at 03:39:57PM -0700, Bart Van Assche wrote:
> Make sure that zoned writes (REQ_OP_WRITE and REQ_OP_WRITE_ZEROES) are
> submitted in LBA order. This patch does not affect REQ_OP_WRITE_APPEND
> requests.

As said before this is not correct.  What we need to instead is to
support proper patch insertation when the at_head flag is set so
that the requests get inserted before the existing requests, but
in ordered they are passed to the I/O scheduler.

This also needs to be done for the other two I/O schedulers.