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Date: Tue, 2 Dec 2025 14:29:43 +0100
From: Christoph Hellwig <hch@lst.de>
To: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: linux-btrfs@vger.kernel.org, Naohiro Aota <naohiro.aota@wdc.com>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] btrfs: zoned: don't zone append to conventional zone
Message-ID: <20251202132943.GA25391@lst.de>
References: <20251202101631.155235-1-johannes.thumshirn@wdc.com>
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On Tue, Dec 02, 2025 at 11:16:31AM +0100, Johannes Thumshirn wrote:
> In case of a zoned RAID, it can happen that a data write is targeting a
> sequential write required zone and a conventional zone. In this case the
> bio will be marked as REQ_OP_ZONE_APPEND but for the conventional zone,
> this needs to be REQ_OP_WRITE.
> 
> This is a partial revert of commit d5e4377d5051 ("btrfs: split zone append
> bios in btrfs_submit_bio") which was introduced before zoned RAID.

Hmm, how does the BLOCK_GROUP_FLAG_SEQUENTIAL_ZONE flag used by
btrfs_use_zone_append actually work for the raid code?

Either way, this is a bit ugly as we now special case zone append in
multiple places.  Can we just pass the use_append flag down to
btrfs_submit_dev_bio and only set REQ_OP_ZONE_APPEND there to keep it
all tidy?