Re: [PATCH v4 08/12] file-posix: remove the zone append write granularity check

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Mon, Sep 07, 2026 at 01:07:43PM +0200, Niklas Cassel wrote:
> The check rejects a zone append whose individual iovec lengths are not
> multiples of the zone write granularity. That is stricter than the
> constraint it is meant to enforce, which applies to the size of the
> request as a whole. A request whose total is properly aligned but which
> is split across, say, a 512 byte and a 3584 byte iovec is refused here,
> even though the iovec boundaries do not survive into the scatter gather
> list that reaches the device.
> 
> Nor is the driver the right place to enforce it. The kernel and the
> device validate writes to a sequential zone themselves, which is why the
> same function already passes the request length down without comparing it
> against BlockLimits.max_append_sectors. The sector granularity that holds
> for every backend is now checked once in bdrv_co_zone_append(), and a
> frontend enforces the granularity it advertises to its guest.
> 
> Drop the check. BlockLimits.write_granularity is now set in one place, by
> this driver from the zone_write_granularity queue attribute, and read in
> one place, by the frontend that reports it.
> 
> Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> ---
>  block/file-posix.c | 16 +---------------
>  1 file changed, 1 insertion(+), 15 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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