Re: [PATCH v2 1/2] common/rc,xfs/207: Adding a common helper function to check xflag bits on a given file

[Ritesh Harjani (IBM) <ritesh.list@gmail.com>]

"Darrick J. Wong" <djwong@kernel.org> writes:

> On Fri, Nov 15, 2024 at 09:45:58AM +0530, Nirjhar Roy wrote:
>> This patch defines a common helper function to test whether any of
>> fsxattr xflags field is set or not. We will use this helper in the next
>> patch for checking extsize (e) flag.
>> 
>> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
>> Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
>> Signed-off-by: Nirjhar Roy <nirjhar@linux.ibm.com>
>> ---
>>  common/rc     |  7 +++++++
>>  tests/xfs/207 | 13 ++-----------
>>  2 files changed, 9 insertions(+), 11 deletions(-)
>> 
>> diff --git a/common/rc b/common/rc
>> index 2af26f23..fc18fc94 100644
>> --- a/common/rc
>> +++ b/common/rc
>> @@ -41,6 +41,13 @@ _md5_checksum()
>>  	md5sum $1 | cut -d ' ' -f1
>>  }
>>  
>> +# Check whether a fsxattr xflags character ($2) field is set on a given file ($1).
>> +# e.g, fsxattr.xflags =  0x80000800 [----------e-----X]
>> +_test_fsx_xflags_field()
>
> How about we call this "_test_fsxattr_xflag" instead?
>
> fsx is already something else in fstests.
>
>> +{
>> +    grep -q "fsxattr.xflags.*\[.*$2.*\]" <($XFS_IO_PROG -c "stat" "$1")
>> +}
>
> Not sure why this lost the xfs_io | grep -q structure.  The return value
> of the whole expression will always be the return value of the last
> command in the pipeline.
>

I guess it was suggested here [1]

[1]: https://lore.kernel.org/all/20241025025651.okneano7d324nl4e@dell-per750-06-vm-08.rhts.eng.pek2.redhat.com/

root-> grep -q "hello" <(echo "hello world"); echo $?
0

The cmd is not using the unnamed pipes ("|") any more. It's spawning the
process () which does echo "hello world" and creating a named pipe or
say temporary FD <() which is being read by grep now. So we still will
have the correct return value. Slightly inefficitent compared to unnamed
pipes though I agree. 

> (Correct?  I hate bash...)
>

root-> ls -la <(echo "hello world");
lr-x------ 1 root root 64 Nov 16 00:42 /dev/fd/63 -> 'pipe:[74211850]'

Did I make you hate it more? ;) 


-ritesh

> --D
>
>> +
>>  # Write a byte into a range of a file
>>  _pwrite_byte() {
>>  	local pattern="$1"
>> diff --git a/tests/xfs/207 b/tests/xfs/207
>> index bbe21307..4f6826f3 100755
>> --- a/tests/xfs/207
>> +++ b/tests/xfs/207
>> @@ -21,15 +21,6 @@ _require_cp_reflink
>>  _require_xfs_io_command "fiemap"
>>  _require_xfs_io_command "cowextsize"
>>  
>> -# Takes the fsxattr.xflags line,
>> -# i.e. fsxattr.xflags = 0x0 [--------------C-]
>> -# and tests whether a flag character is set
>> -test_xflag()
>> -{
>> -    local flg=$1
>> -    grep -q "\[.*${flg}.*\]" && echo "$flg flag set" || echo "$flg flag unset"
>> -}
>> -
>>  echo "Format and mount"
>>  _scratch_mkfs > $seqres.full 2>&1
>>  _scratch_mount >> $seqres.full 2>&1
>> @@ -65,14 +56,14 @@ echo "Set cowextsize and check flag"
>>  $XFS_IO_PROG -c "cowextsize 1048576" $testdir/file3 | _filter_scratch
>>  _scratch_cycle_mount
>>  
>> -$XFS_IO_PROG -c "stat" $testdir/file3 | grep 'fsxattr.xflags' | test_xflag "C"
>> +_test_fsx_xflags_field "$testdir/file3" "C" && echo "C flag set" || echo "C flag unset"
>>  $XFS_IO_PROG -c "cowextsize" $testdir/file3 | _filter_scratch
>>  
>>  echo "Unset cowextsize and check flag"
>>  $XFS_IO_PROG -c "cowextsize 0" $testdir/file3 | _filter_scratch
>>  _scratch_cycle_mount
>>  
>> -$XFS_IO_PROG -c "stat" $testdir/file3 | grep 'fsxattr.xflags' | test_xflag "C"
>> +_test_fsx_xflags_field "$testdir/file3" "C" && echo "C flag set" || echo "C flag unset"
>>  $XFS_IO_PROG -c "cowextsize" $testdir/file3 | _filter_scratch
>>  
>>  status=0
>> -- 
>> 2.43.5
>> 
>>