2022-05-16 09:46:41

by Ojaswin Mujoo

Subject: [PATCH v2] common/rc: Modify _require_batched_discard to improve test coverage

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 <[email protected]>
Reviewed-by: Ritesh Harjani <[email protected]>
---

Changes since v1 [1]

* Changed $RET to a local variable
* Fixed the grep command

[1]
https://lore.kernel.org/all/[email protected]/

common/rc | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/common/rc b/common/rc
index e2d3d72a..f366e409 100644
--- a/common/rc
+++ b/common/rc
@@ -3858,7 +3858,13 @@ _require_batched_discard()
exit 1
fi
_require_fstrim
- $FSTRIM_PROG $1 > /dev/null 2>&1 || _notrun "FITRIM not supported on $1"
+
+ grep -q "not supported" <($FSTRIM_PROG $1 2>&1)
+ local ret=$?
+ if [ "$ret" = "0" ]
+ then
+ _notrun "FITRIM not supported on $1"
+ fi
}

_require_dumpe2fs()
--
2.27.0

2022-05-16 11:13:59

by Zorro Lang

Subject: Re: [PATCH v2] common/rc: Modify _require_batched_discard to improve test coverage

On Mon, May 16, 2022 at 12:09:51PM +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 <[email protected]>
> Reviewed-by: Ritesh Harjani <[email protected]>
> ---
>
> Changes since v1 [1]
>
> * Changed $RET to a local variable
> * Fixed the grep command
>
> [1]
> https://lore.kernel.org/all/[email protected]/
>
> common/rc | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/common/rc b/common/rc
> index e2d3d72a..f366e409 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -3858,7 +3858,13 @@ _require_batched_discard()
> exit 1
> fi
> _require_fstrim
> - $FSTRIM_PROG $1 > /dev/null 2>&1 || _notrun "FITRIM not supported on $1"
> +
> + grep -q "not supported" <($FSTRIM_PROG $1 2>&1)
> + local ret=$?
> + if [ "$ret" = "0" ]

Oh I forgot to ask why we need to add a variable (ret), to record the return
value at here. Why can't use "$?" directly? e.g.

grep -q "not supported" <($FSTRIM_PROG $1 2>&1)
if [ $? -eq 0 ]

Others look good to me.

Thanks,
Zorro

> + then
> + _notrun "FITRIM not supported on $1"
> + fi
> }
>
> _require_dumpe2fs()
> --
> 2.27.0
>