nfs-iostat.py: divide by zero with fresh mount

When an export is freshly mounted, /proc/self/mountstats displays age = 0.
This causes nfs-iostat.py to divide by zero throwing an error.  When we
have age = 0, other stats are greater than 0, so we'll set age = 1 and
print the relevant stats.

Signed-off-by: Kevin Constantine <kevin.constantine@disneyanimation.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

diff --git a/tools/nfs-iostat/nfs-iostat.py b/tools/nfs-iostat/nfs-iostat.py
index 2d0b1433b948ef4884a987f3bd556376294f413c..1207674e4ad7c19b95fbddfe0de7931708015856 100644 (file)
--- a/tools/nfs-iostat/nfs-iostat.py
+++ b/tools/nfs-iostat/nfs-iostat.py
@@ -366,6 +366,12 @@ class DeviceData:
         sends = float(self.__rpc_data['rpcsends'])
         if sample_time == 0:
             sample_time = float(self.__nfs_data['age'])
+        #  sample_time could still be zero if the export was just mounted.
+        #  Set it to 1 to avoid divide by zero errors in this case since we'll
+        #  likely still have relevant mount statistics to show.
+        #
+        if sample_time == 0:
+            sample_time = 1;
         if sends != 0:
             backlog = (float(self.__rpc_data['backlogutil']) / sends) / sample_time
         else: