Re: [PATCH v3 08/10] null_blk: Support REQ_OP_ZONE_APPEND

On 2020/03/28 2:26, Christoph Hellwig wrote:

On Sat, Mar 28, 2020 at 01:50:10AM +0900, Johannes Thumshirn wrote:

quoted

From: Damien Le Moal <redacted>

Support REQ_OP_ZONE_APPEND requests for zone mode null_blk devices.
Use the internally tracked zone write pointer position as the actual
write position, which is returned using the command request __sector
field in the case of an mq device and using the command BIO sector in
the case of a BIO device. Since the write position is used for data copy
in the case of a memory backed device, reverse the order in which
null_handle_zoned() and null_handle_memory_backed() are called to ensure
that null_handle_memory_backed() sees the correct write position for
REQ_OP_ZONE_APPEND operations.

I think moving null_zone_write earlier actually is a bug-fixd as is
as we should not touch memory if the zone condition or write pointer
isn't valid for a write.  I'd suggest splitting that out as a bug fix
and move it to the start of the series so that Jens can pick it up
ASAP.

OK. Will do that.

Johannes,

If you agree, I will send a patch separately for the move of null_handle_zoned()
before the memcopy. While at it, I think I could also take patch 7 from this
series and send it together with the reset all cleanup using req flag. That will
make a mini series for cleaning & fixing null blk.

Otherwise this looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

-- 
Damien Le Moal
Western Digital Research