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Date:   Sun, 26 Mar 2023 22:22:39 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc:     Christoph Hellwig <hch@infradead.org>, Qu Wenruo <wqu@suse.com>,
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Subject: Re: [PATCH v4 04/13] btrfs: introduce a new helper to submit write
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On Mon, Mar 27, 2023 at 12:32:22PM +0800, Qu Wenruo wrote:
> > Not crossing the stripe boundary is not enough, for zone append it
> > also must not cross the zone append limit, which (at least in theory)
> > can be arbitrarily small.
> 
> Do you mean that we can have some real zone append limit which is even
> smaller than 64K?
> 
> If so, then the write helper can be more complex than I thought...

In theory it can be as small as a single LBA.  It might make sense
to require a minimum of 64k for btrfs, and reject the writable mount
if it is not, as a device with just a 64k zone append limit or smaller
would be really horrible to use anyway.