Re: [PATCH v3] common/rc: Modify _require_batched_discard to improve test coverage

[Ojaswin Mujoo]

Greetings,

Please let me know if there are any reviews/suggestions on this
patch.

Thank you!

On Mon, May 16, 2022 at 02:15:05PM +0530, Ojaswin Mujoo wrote:
> A recent ext4 patch discussed [1] that some devices (eg LVMs) can
> have a discard granularity as big as 42MB which makes it larger
> than the group size of ext4 FS with 1k BS.  This causes the FITRIM
> IOCTL to fail.
> 
> This case was not correctly handled by this test since
> "_require_batched_discard" incorrectly interpreted the FITRIM
> failure as SCRATCH_DEV not supporting the IOCTL. This caused the test
> to report "not run" instead of "failed" in case of large discard granularity.
> 
> Fix "_require_batched_discard" to use a more accurate method
> to determine if discard is supported.
> 
> [1] commit 173b6e383d2
>     ext4: avoid trim error on fs with small groups
> 
> Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
> Reviewed-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx>
> ---
> 
> Changes since v2 [1] 
> 
> *  Eliminated redundant $ret variable
> 
> [1]
> https://lore.kernel.org/all/20220516063951.87838-1-ojaswin@xxxxxxxxxxxxx/