Re: [PATCH v3 2/3] common/rc: Add a new _require_scratch_extsize helper function

[Nirjhar Roy <nirjhar@linux.ibm.com>]

On 11/21/24 13:23, Ritesh Harjani (IBM) wrote:
> Nirjhar Roy <nirjhar@linux.ibm.com> writes:
>
>> _require_scratch_extsize helper function will be used in the
>> the next patch to make the test run only on filesystems with
>> extsize support.
>>
>> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
>> Signed-off-by: Nirjhar Roy <nirjhar@linux.ibm.com>
>> ---
>>   common/rc | 17 +++++++++++++++++
>>   1 file changed, 17 insertions(+)
>>
>> diff --git a/common/rc b/common/rc
>> index cccc98f5..995979e9 100644
>> --- a/common/rc
>> +++ b/common/rc
>> @@ -48,6 +48,23 @@ _test_fsxattr_xflag()
>>   	grep -q "fsxattr.xflags.*\[.*$2.*\]" <($XFS_IO_PROG -c "stat -v" "$1")
>>   }
>>   
>> +# This test requires extsize support on the  filesystem
>> +_require_scratch_extsize()
>> +{
>> +	_require_scratch
> _require_xfs_io_command "extsize"
>
> ^^^ Don't we need this too?
Yes, good point. I will add this in the next revision.
>
>> +	_scratch_mkfs > /dev/null
>> +	_scratch_mount
>> +	local filename=$SCRATCH_MNT/$RANDOM
>> +	local blksz=$(_get_block_size $SCRATCH_MNT)
>> +	local extsz=$(( blksz*2 ))
>> +	local res=$($XFS_IO_PROG -c "open -f $filename" -c "extsize $extsz" \
>> +		-c "extsize")
>> +	_scratch_unmount
>> +	grep -q "\[$extsz\] $filename" <(echo $res) || \
>> +		_notrun "this test requires extsize support on the filesystem"
> Why grep when we can simply just check the return value of previous xfs_io command?
No, I don't think we can rely on the return value of xfs_io. For ex, 
let's look at the following set of commands which are ran on an ext4 system:

root@AMARPC: /mnt1/test$ xfs_io -V
xfs_io version 5.13.0
root@AMARPC: /mnt1/test$ touch new
root@AMARPC: /mnt1/test$ xfs_io -c "extsize 8k"  new
foreign file active, extsize command is for XFS filesystems only
root@AMARPC: /mnt1/test$ echo "$?"
0
This incorrect return value might have been fixed in some later versions 
of xfs_io but there are still versions where we can't solely rely on the 
return value.
>
>> +}
>> +
>> +
> ^^ Extra newline.

Noted. I will fix this.

--NR

>
>>   # Write a byte into a range of a file
>>   _pwrite_byte() {
>>   	local pattern="$1"
>> -- 
>> 2.43.5

-- 
---
Nirjhar Roy
Linux Kernel Developer
IBM, Bangalore