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Date:   Tue, 10 Jan 2023 07:58:22 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Pankaj Raghav <p.raghav@samsung.com>
Cc:     axboe@kernel.dk, kernel@pankajraghav.com,
        linux-kernel@vger.kernel.org, hare@suse.de, bvanassche@acm.org,
        snitzer@kernel.org, dm-devel@redhat.com,
        damien.lemoal@opensource.wdc.com, linux-nvme@lists.infradead.org,
        hch@lst.de, linux-block@vger.kernel.org, gost.dev@samsung.com
Subject: Re: [PATCH 7/7] dm: call dm_zone_endio after the target endio
 callback for zoned devices
Message-ID: <20230110065822.GF10289@lst.de>
References: <20230106083317.93938-1-p.raghav@samsung.com> <CGME20230106083323eucas1p2f0f6d5d5c1c3713be35b841157ae463e@eucas1p2.samsung.com> <20230106083317.93938-8-p.raghav@samsung.com>
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On Fri, Jan 06, 2023 at 09:33:17AM +0100, Pankaj Raghav wrote:
> dm_zone_endio() updates the bi_sector of orig bio for zoned devices that
> uses either native append or append emulation, and it is called before the
> endio of the target. But target endio can still update the clone bio
> after dm_zone_endio is called, thereby, the orig bio does not contain
> the updated information anymore.
> 
> Currently, this is not a problem as the targets that support zoned devices
> such as dm-zoned, dm-linear, and dm-crypt do not have an endio function,
> and even if they do (such as dm-flakey), they don't modify the
> bio->bi_iter.bi_sector of the cloned bio that is used to update the
> orig_bio's bi_sector in dm_zone_endio function.
> 
> Call dm_zone_endio for zoned devices after calling the target's endio
> function.

This looks sensible, but I fail to see why we need this or how it fits
into the earlier block layer part of the series.