[PATCH v5 1/8] common/rc: Introduce new helpers for DAX mount options and FS_XFLAG_DAX

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

1) _require_scratch_dax_mountopt() checks both old and new DAX mount option
2) _require_dax_iflag() checks FS_XFLAG_DAX

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
---

V4->V5:
1) Rename _require_scratch_dax_iflag to _require_dax_iflag
2) Redirect the output of _try_scratch_mount to /dev/null

 common/rc | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/common/rc b/common/rc
index f17b19f2..498ce230 100644
--- a/common/rc
+++ b/common/rc
@@ -3188,6 +3188,41 @@ _require_scratch_dax()
 	_scratch_unmount
 }
 
+_require_scratch_dax_mountopt()
+{
+	local mountopt=$1
+	local output
+
+	_require_scratch
+	_scratch_mkfs > /dev/null 2>&1
+	_try_scratch_mount "-o $mountopt" > /dev/null 2>&1 || \
+		_notrun "mount $SCRATCH_DEV with $mountopt failed"
+
+	output=$(_fs_options $SCRATCH_DEV)
+
+	# For new dax mount option, /proc/mounts shows different outputs if we
+	# mount with -o dax=inode on ext4 and xfs so skip checking it.
+	# /proc/mounts shows 'dax=inode' on ext4 but shows nothing on xfs.
+	if [ "$mountopt" != "dax=inode" ]; then
+		echo $output | grep -qw "$mountopt" || \
+			_notrun "$SCRATCH_DEV $FSTYP does not support -o $mountopt"
+	fi
+
+	# For new dax mount option, /proc/mounts shows "dax=never" if we
+	# mount with -o dax on xfs and underlying device doesn't support dax.
+	if [ "$mountopt" = "dax" ]; then
+		echo $output | grep -qw "dax=never" && \
+			_notrun "$SCRATCH_DEV $FSTYP does not support -o $mountopt"
+	fi
+
+	_scratch_unmount
+}
+
+_require_dax_iflag()
+{
+	_require_xfs_io_command "chattr" "x"
+}
+
 # Does norecovery support by this fs?
 _require_norecovery()
 {
-- 
2.21.0