On 25/03/2020 10:48, hch@infradead.org wrote:

On Wed, Mar 25, 2020 at 09:45:39AM +0000, Johannes Thumshirn wrote:

quoted

Can you please elaborate on that? Why doesn't this hold true for a
normal file system? If we split the DIO write into multiple BIOs with
zone-append, there is nothing which guarantees the order of the written
data (at least as far as I can see).

Of course nothing gurantees the order.  But the whole point is that the
order does not matter.

Ok now I'm totally lost. The order of data inside an extent does matter, 
otherwise we have data corruption.