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Date:   Mon, 24 Jul 2023 08:04:10 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Naohiro Aota <naohiro.aota@wdc.com>
Cc:     linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 2/8] btrfs: zoned: defer advancing meta_write_pointer
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References: <cover.1690171333.git.naohiro.aota@wdc.com>
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> @@ -1773,23 +1773,15 @@ bool btrfs_check_meta_write_pointer(struct btrfs_fs_info *fs_info,
>  		*cache_ret = cache;
>  	}
>  
> +	/* Someone already start writing this eb. */
> +	if (cache->meta_write_pointer > eb->start)
> +		return true;

This is actually a behavior change and not mentioned in the commit log.
How is this supposed to work?  If eb->start is before the write pointer
we're going to get a write reordering problem.

The other bits in the patch look like a very nice improvement, though.