[PATCH 1/4] common/rc: Add helper to calculate percetage of free space available

It calculates percentage of filesystem available space and returns it
in MB. This helper will be used in the following test/generic fixes.

Signed-off-by: Lukas Herbolt <[email protected]>
---
 common/rc | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/common/rc b/common/rc
index 5fe44e2158ff..32c566cdb68a 100644
--- a/common/rc
+++ b/common/rc
@@ -6189,6 +6189,14 @@ _require_fanotify_ioerrors()
 	_notrun "$FSTYP does not support fanotify ioerrors"
 }
 
+# Returns percentage of available space on given mount point.
+# usage example:
+# _mb_pct_of_available_space <mount point> <percents>
+#
+_mb_pct_of_available_space()
+{
+        _df_device $1 | $AWK_PROG -v pct=$2 '{printf "%.f", (($5*(pct/100))/1024)}'
+}
 ################################################################################
 # make sure this script returns success
 /bin/true
-- 
2.53.0