[PATCH 3/4] xfs: refactor filesystem realtime geometry detection logic

["Darrick J. Wong" <djwong@kernel.org>]

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      |   31 +++++++++++++++++++++++++++++--
 tests/xfs/146   |    2 +-
 tests/xfs/147   |    2 +-
 tests/xfs/530   |    3 +--
 5 files changed, 33 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 9b6575b5f2..a995e0b5da 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'
+}
+
+# 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'
+}
+
 # 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"
 }
 
 # Get the directory block size of a mounted filesystem.
@@ -427,13 +445,22 @@ _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")"
+	case "$feat" in
+	"realtime")
+		feat="rtextents"
+		feat_regex="[1-9][0-9]*"
+		;;
+	esac
+
+	local answer="$($XFS_INFO_PROG "$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