Re: [PATCH v2 2/2] fsx: Add '-a' option to skip unsupported keep size automatically

From: Xiao Yang <yangx.jy@cn.fujitsu.com>
To: fstests <fstests@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] fsx: Add '-a' option to skip unsupported keep size automatically
Date: Tue, 7 Jan 2020 10:10:29 +0800	[thread overview]
Message-ID: <5E13E895.8020005@cn.fujitsu.com> (raw)
In-Reply-To: <CAOQ4uxh91oRB03UGuqhSgASeY7-OtQD3wMRdOQ-SL0UBgdMPHQ@mail.gmail.com>

On 2020/1/6 19:24, Amir Goldstein wrote:
> A very strong NACK!
>
> Why are you making this change?
> Did you read the description of the tests and try to understand the sequence
> prescribed in the replay-ops file?
>
> Those are reproducers to specific issues that require a very specific sequence
> of operations and it seems to me that 'keep_size' is there for a reason in every
> one of those tests.
>
> For example, take the test generic/456, which I wrote, it has this link in the
> comment above fsxops to a very elaborate email from Ted explaining the
> problem:https://marc.info/?l=linux-ext4&m=151137380830381&w=2
>
> You cannot just remove 'keep_size' from the test because then the test
> doesn't do what it is intended to do.
>
> Did you read my reply to Eryu's patch which he referred you to?
> https://spinics.net/lists/fstests/msg08007.html
>
> Instead of allowing test generic/456 to run on fs which doesn't support
> FL_KEEP_SIZE, you should change the test to*require*  support for
> FL_KEEP_SIZE as well as require support for punch/zero/collapse:
>
> _require_xfs_io_command "falloc" "-k"
> _require_xfs_io_command "fpunch"
> _require_xfs_io_command "fzero"
> _require_xfs_io_command "fcollapse"
>
> Same for the other tests that you changed to ignore keep_size.

Hi Amir,

Thanks for your comment.

I had a doubt and asked Eryu after sending the second patch:
https://www.spinics.net/lists/fstests/msg13278.html

Current fsx skips all unsupported ops(e.g. punch_hole, zero_range, 
collapse_range) automatically even if they are specified by 
--replay-ops.  Is this existing logic wrong?

I read your suggestion before, but i just have a worry:
xfs_io commands cannot detect the supported flags of fallocate() 
correctly in one case(i.e. xfs_io commands are not supported but 
fallocate(2) supports flags).

fsx has many test_ functions to check these flags, so we can make fsx 
call only these test_ functions by adding a option and then report "not 
run" by analyzing the generated output.

Best Regards,
Xiao Yang