Re: [PATCH 3/3] xfs: refactor filesystem realtime geometry detection logic

[Zorro Lang <zlang@kernel.org>]

On Tue, Oct 18, 2022 at 03:45:38PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> There are a lot of places where we open-code detecting the realtime
> extent size and extent count of a specific filesystem.  Refactor this
> into a couple of helpers to clean up the code.
> 
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  common/populate |    2 +-
>  common/xfs      |   29 +++++++++++++++++++++++++++--
>  tests/xfs/146   |    2 +-
>  tests/xfs/147   |    2 +-
>  tests/xfs/530   |    3 +--
>  5 files changed, 31 insertions(+), 7 deletions(-)
> 
> 
> diff --git a/common/populate b/common/populate
> index 23b2fecf69..d9d4c6c300 100644
> --- a/common/populate
> +++ b/common/populate
> @@ -323,7 +323,7 @@ _scratch_xfs_populate() {
>  	fi
>  
>  	# Realtime Reverse-mapping btree
> -	is_rt="$($XFS_INFO_PROG "${SCRATCH_MNT}" | grep -c 'rtextents=[1-9]')"
> +	is_rt="$(_xfs_get_rtextents "$SCRATCH_MNT")"
>  	if [ $is_rmapbt -gt 0 ] && [ $is_rt -gt 0 ]; then
>  		echo "+ rtrmapbt btree"
>  		nr="$((blksz * 2 / 32))"
> diff --git a/common/xfs b/common/xfs
> index 6445bfd9db..20da537a9d 100644
> --- a/common/xfs
> +++ b/common/xfs
> @@ -174,6 +174,24 @@ _scratch_mkfs_xfs()
>  	return $mkfs_status
>  }
>  
> +# Get the number of realtime extents of a mounted filesystem.
> +_xfs_get_rtextents()
> +{
> +	local path="$1"
> +
> +	$XFS_INFO_PROG "$path" | grep 'rtextents' | \
> +		sed -e 's/^.*rtextents=\([0-9]*\).*$/\1/g'

Same as patch 2/3, how about:

	$XFS_INFO_PROG "$path" | sed -n "s/^.*rtextents=\([[:digit:]]*\).*/\1/p"

and ...

> +}
> +
> +# Get the realtime extent size of a mounted filesystem.
> +_xfs_get_rtextsize()
> +{
> +	local path="$1"
> +
> +	$XFS_INFO_PROG "$path" | grep 'realtime.*extsz' | \
> +		sed -e 's/^.*extsz=\([0-9]*\).*$/\1/g'

...
	$XFS_INFO_PROG "$path" | sed -n "s/^realtime.*extsz=\([[:digit:]]*\).*/\1/p"

> +}
> +
>  # Get the size of an allocation unit of a file.  Normally this is just the
>  # block size of the file, but for realtime files, this is the realtime extent
>  # size.
> @@ -191,7 +209,7 @@ _xfs_get_file_block_size()
>  	while ! $XFS_INFO_PROG "$path" &>/dev/null && [ "$path" != "/" ]; do
>  		path="$(dirname "$path")"
>  	done
> -	$XFS_INFO_PROG "$path" | grep realtime | sed -e 's/^.*extsz=\([0-9]*\).*$/\1/g'
> +	_xfs_get_rtextsize "$path"
>  }
>  
>  # Decide if this path is a file on the realtime device
> @@ -436,13 +454,20 @@ _require_xfs_crc()
>  # third option is -v, echo 1 for success and 0 for not.
>  #
>  # Starting with xfsprogs 4.17, this also works for unmounted filesystems.
> +# The feature 'realtime' looks for rtextents > 0.
>  _xfs_has_feature()
>  {
>  	local fs="$1"
>  	local feat="$2"
>  	local verbose="$3"
> +	local feat_regex="1"
>  
> -	local answer="$($XFS_INFO_PROG "$fs" 2>&1 | grep -w -c "$feat=1")"
> +	if [ "$feat" = "realtime" ]; then
> +		feat="rtextents"
> +		feat_regex="[1-9][0-9]*"
> +	fi

How about use this format:

case "$feat" in
realtime)
	feat="rtextents"
	feat_regex="[1-9][0-9]*"
	;;
...)
	feat="..."
	feat_regex="..."
	;;
*)
	feat="$2“
	feat_regex="1"
	;;
esac

due to I think you might add more "$feat" which not simply equal to 1/0 later :)

Others looks good to me.

Thanks,
Zorro

> +
> +	local answer="$($XFS_INFO_PROG "$fs" 2>&1 | grep -E -w -c "$feat=$feat_regex")"
>  	if [ "$answer" -ne 0 ]; then
>  		test "$verbose" = "-v" && echo 1
>  		return 0
> diff --git a/tests/xfs/146 b/tests/xfs/146
> index 5516d396bf..123bdff59f 100755
> --- a/tests/xfs/146
> +++ b/tests/xfs/146
> @@ -31,7 +31,7 @@ _scratch_mkfs > $seqres.full
>  _scratch_mount >> $seqres.full
>  
>  blksz=$(_get_block_size $SCRATCH_MNT)
> -rextsize=$($XFS_INFO_PROG $SCRATCH_MNT | grep realtime.*extsz | sed -e 's/^.*extsz=\([0-9]*\).*$/\1/g')
> +rextsize=$(_xfs_get_rtextsize "$SCRATCH_MNT")
>  rextblks=$((rextsize / blksz))
>  
>  echo "blksz $blksz rextsize $rextsize rextblks $rextblks" >> $seqres.full
> diff --git a/tests/xfs/147 b/tests/xfs/147
> index e21fdd330c..33b3c99633 100755
> --- a/tests/xfs/147
> +++ b/tests/xfs/147
> @@ -29,7 +29,7 @@ _scratch_mkfs -r extsize=256k > $seqres.full
>  _scratch_mount >> $seqres.full
>  
>  blksz=$(_get_block_size $SCRATCH_MNT)
> -rextsize=$($XFS_INFO_PROG $SCRATCH_MNT | grep realtime.*extsz | sed -e 's/^.*extsz=\([0-9]*\).*$/\1/g')
> +rextsize=$(_xfs_get_rtextsize "$SCRATCH_MNT")
>  rextblks=$((rextsize / blksz))
>  
>  echo "blksz $blksz rextsize $rextsize rextblks $rextblks" >> $seqres.full
> diff --git a/tests/xfs/530 b/tests/xfs/530
> index c960738db7..56f5e7ebdb 100755
> --- a/tests/xfs/530
> +++ b/tests/xfs/530
> @@ -73,8 +73,7 @@ _try_scratch_mount || _notrun "Couldn't mount fs with synthetic rt volume"
>  formatted_blksz="$(_get_block_size $SCRATCH_MNT)"
>  test "$formatted_blksz" -ne "$dbsize" && \
>  	_notrun "Tried to format with $dbsize blocksize, got $formatted_blksz."
> -$XFS_INFO_PROG $SCRATCH_MNT | grep -E -q 'realtime.*blocks=0' && \
> -	_notrun "Filesystem should have a realtime volume"
> +_require_xfs_has_feature "$SCRATCH_MNT" realtime
>  
>  echo "Consume free space"
>  fillerdir=$SCRATCH_MNT/fillerdir
>