linux-ext4 - Re: [PATCH v3 5/6] common/config: Introduce

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Message-ID: <0e4817b5-bd20-4ea6-93f4-ec0bee9bf833@gmail.com>
Date: Tue, 8 Apr 2025 21:45:53 +0530
From: "Nirjhar Roy (IBM)" <nirjhar.roy.lists@...il.com>
To: "Ritesh Harjani (IBM)" <ritesh.list@...il.com>, fstests@...r.kernel.org
Cc: linux-ext4@...r.kernel.org, linux-xfs@...r.kernel.org,
 ojaswin@...ux.ibm.com, djwong@...nel.org, zlang@...nel.org,
 david@...morbit.com
Subject: Re: [PATCH v3 5/6] common/config: Introduce _exit wrapper around exit
 command


On 4/8/25 14:43, Ritesh Harjani (IBM) wrote:
> "Nirjhar Roy (IBM)" <nirjhar.roy.lists@...il.com> writes:
>
>> We should always set the value of status correctly when we are exiting.
>> Else, "$?" might not give us the correct value.
>> If we see the following trap
>> handler registration in the check script:
>>
>> if $OPTIONS_HAVE_SECTIONS; then
>>       trap "_kill_seq; _summary; exit \$status" 0 1 2 3 15
>> else
>>       trap "_kill_seq; _wrapup; exit \$status" 0 1 2 3 15
>> fi
>>
>> So, "exit 1" will exit the check script without setting the correct
>> return value. I ran with the following local.config file:
>>
>> [xfs_4k_valid]
>> FSTYP=xfs
>> TEST_DEV=/dev/loop0
>> TEST_DIR=/mnt1/test
>> SCRATCH_DEV=/dev/loop1
>> SCRATCH_MNT=/mnt1/scratch
>>
>> [xfs_4k_invalid]
>> FSTYP=xfs
>> TEST_DEV=/dev/loop0
>> TEST_DIR=/mnt1/invalid_dir
>> SCRATCH_DEV=/dev/loop1
>> SCRATCH_MNT=/mnt1/scratch
>>
>> This caused the init_rc() to catch the case of invalid _test_mount
>> options. Although the check script correctly failed during the execution
>> of the "xfs_4k_invalid" section, the return value was 0, i.e "echo $?"
>> returned 0. This is because init_rc exits with "exit 1" without
>> correctly setting the value of "status". IMO, the correct behavior
>> should have been that "$?" should have been non-zero.
>>
>> The next patch will replace exit with _exit.
>>
>> Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@...il.com>
>> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@...il.com>
>> Reviewed-by: Dave Chinner <dchinner@...hat.com>
>> ---
>>   common/config | 8 ++++++++
>>   1 file changed, 8 insertions(+)
>>
>> diff --git a/common/config b/common/config
>> index 79bec87f..eb6af35a 100644
>> --- a/common/config
>> +++ b/common/config
>> @@ -96,6 +96,14 @@ export LOCAL_CONFIGURE_OPTIONS=${LOCAL_CONFIGURE_OPTIONS:=--enable-readline=yes}
>>   
>>   export RECREATE_TEST_DEV=${RECREATE_TEST_DEV:=false}
>>   
>> +# This functions sets the exit code to status and then exits. Don't use
>> +# exit directly, as it might not set the value of "status" correctly.
> ...as it might not set the value of "$status" correctly, which is used
> as an exit code in the trap handler routine set up by the check script.
>
>> +_exit()
>> +{
>> +	status="$1"
>> +	exit "$status"
>> +}
>> +
> I agree with Darrick’s suggestion here. It’s safer to update status only
> when an argument is passed - otherwise, it’s easy to trip over this.
>
> Let’s also avoid defaulting status to 0 inside _exit(). That way, if the
> caller forgets to pass an argument but has explicitly set status
> earlier, we preserve the intended value.
>
> We should update _exit() with...
>
> test -n "$1" && status="$1"

Okay, so in that case if someone does "status=<value>;_exit", we should 
end up with the "<value>" instead of something else, right?

--NR

>
> -ritesh
>
>
>>   # Handle mkfs.$fstyp which does (or does not) require -f to overwrite
>>   set_mkfs_prog_path_with_opts()
>>   {
>> -- 
>> 2.34.1

-- 
Nirjhar Roy
Linux Kernel Developer
IBM, Bangalore