Re: [PATCH] zonefs: do not use append if device does not support it

[Damien Le Moal]

On 6/27/23 12:45, Christoph Hellwig wrote:
> On Mon, Jun 26, 2023 at 06:47:52PM +0200, Andreas Hindborg wrote:
>> From: "Andreas Hindborg (Samsung)" <nmi@xxxxxxxxxxxx>
>>
>> Zonefs will try to use `zonefs_file_dio_append()` for direct sync writes even if
>> device `max_zone_append_sectors` is zero. This will cause the IO to fail as the
>> io vector is truncated to zero. It also causes a call to
>> `invalidate_inode_pages2_range()` with end set to UINT_MAX, which is probably
>> not intentional. Thus, do not use append when device does not support it.
> 
> How do you even manage to hit this code?  Zone Append is a mandatory
> feature and driver need to check it is available.

ublk driver probably is missing that check ? I have not looked at the code for
zone support.

But thinking of it, we probably would be better off having a generic check for
"q->limits.max_zone_append_sectors != 0" in blk_revalidate_disk_zones().

-- 
Damien Le Moal
Western Digital Research