[PATCH v6 02/12] common/rc: Add fio atomic write helpers

[Ojaswin Mujoo <ojaswin@linux.ibm.com>]

The main motivation of adding this function on top of _require_fio is
that there has been a case in fio where atomic= option was added but
later it was changed to noop since kernel didn't yet have support for
atomic writes. It was then again utilized to do atomic writes in a later
version, once kernel got the support. Due to this there is a point in
fio where _require_fio w/ atomic=1 will succeed even though it would
not be doing atomic writes.

Hence, add an internal helper __require_fio_version to require specific
versions of fio to work past such issues. Further, add the high level
_require_fio_atomic_writes helper which tests can use to ensure fio
has the right version for atomic writes.

Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
---
 common/rc | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/common/rc b/common/rc
index 28fbbcbb..8a023b9d 100644
--- a/common/rc
+++ b/common/rc
@@ -6000,6 +6000,49 @@ _max() {
 	echo $ret
 }
 
+# Due to reasons explained in fio commit 40f1fc11d, fio version between
+# v3.33 and v3.38 have atomic= feature but it is a no-op and doesn't do
+# RWF_ATOMIC write. Hence, use this helper to ensure fio has the
+# required support. Currently, the simplest way we have is to ensure
+# the version.
+_require_fio_atomic_writes() {
+	__require_fio_version "3.38+"
+}
+
+# Check the required fio version. Examples:
+#   __require_fio_version 3.38 (matches 3.38 only)
+#   __require_fio_version 3.38+ (matches 3.38 and above)
+#   __require_fio_version 3.38- (matches 3.38 and below)
+#
+# Internal helper, avoid using directly in tests.
+__require_fio_version() {
+	local req_ver="$1"
+	local fio_ver
+
+	_require_fio
+	_require_math
+
+	fio_ver=$(fio -v | cut -d"-" -f2)
+
+	case "$req_ver" in
+	*+)
+		req_ver=${req_ver%+}
+		test $(_math "$fio_ver >= $req_ver") -eq 1 || \
+			_notrun "need fio >= $req_ver (found $fio_ver)"
+		;;
+	*-)
+		req_ver=${req_ver%-}
+		test $(_math "$fio_ver <= $req_ver") -eq 1 || \
+			_notrun "need fio <= $req_ver (found $fio_ver)"
+		;;
+	*)
+		req_ver=${req_ver%-}
+		test $(_math "$fio_ver == $req_ver") -eq 1 || \
+			_notrun "need fio = $req_ver (found $fio_ver)"
+		;;
+	esac
+}
+
 ################################################################################
 # make sure this script returns success
 /bin/true
-- 
2.49.0