generic/508: fix to check inode creation time feature on scratch mountpoint

_require_btime() just check inode creation time feature on TEST_DIR
mountpoint, but generic/508 needs to do that check on SCRATCH_MNT
mountpoint. Let's add _require_scratch_btime() for that, meanwhile
handling scratch_{mkfs,mount,umount} inside the function to decouple
with caller.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

common/rc

@@ -3830,6 +3830,19 @@ _require_btime()
 	rm -f $TEST_DIR/test_creation_time
 }
 
+_require_scratch_btime()
+{
+	_require_scratch
+	_scratch_mkfs > /dev/null 2>&1
+	_scratch_mount
+
+	$XFS_IO_PROG -f $SCRATCH_MNT/test_creation_time -c "statx -v" \
+		| grep btime >>$seqres.full 2>&1 || \
+		_notrun "inode creation time not supported by this filesystem"
+
+	_scratch_unmount
+}
+
 init_rc
 
 ################################################################################

tests/generic/508

@@ -46,10 +46,10 @@ _supported_os Linux
 _require_test_lsattr
 _require_statx
 _require_xfs_io_command "statx" "-v"
-_require_btime
 
 _require_scratch
 _require_scratch_shutdown
+_require_scratch_btime
 
 _scratch_mkfs >/dev/null 2>&1
 _require_metadata_journaling $SCRATCH_DEV