2020-08-24 15:08:25

by Kenneth Dsouza

Subject: [PATCH] nfs-iostat: divide by zero with fresh mount

When an export is freshly mounted, /proc/self/mountstats displays age = 0.
This causes nfs-iostat 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.

This will prevent a backtrace like this from occurring if nfsiostat is run.

nfsiostat -s 1
Traceback (most recent call last):
File "/usr/sbin/nfsiostat", line 662, in <module>
iostat_command(prog)
File "/usr/sbin/nfsiostat", line 644, in iostat_command
print_iostat_summary(old_mountstats, mountstats, devices, sample_time, options)
File "/usr/sbin/nfsiostat", line 490, in print_iostat_summary
devicelist.sort(key=lambda x: stats[x].ops(time), reverse=True)
File "/usr/sbin/nfsiostat", line 490, in <lambda>
devicelist.sort(key=lambda x: stats[x].ops(time), reverse=True)
File "/usr/sbin/nfsiostat", line 383, in ops
return (sends / sample_time)
ZeroDivisionError: float division by zero

Signed-off-by: Kenneth D'souza <[email protected]>
---
tools/nfs-iostat/nfs-iostat.py | 2 ++
1 file changed, 2 insertions(+)

diff --git a/tools/nfs-iostat/nfs-iostat.py b/tools/nfs-iostat/nfs-iostat.py
index 5556f692..0c6c6dda 100755
--- a/tools/nfs-iostat/nfs-iostat.py
+++ b/tools/nfs-iostat/nfs-iostat.py
@@ -383,6 +383,8 @@ class DeviceData:
sends = float(self.__rpc_data['rpcsends'])
if sample_time == 0:
sample_time = float(self.__nfs_data['age'])
+ if sample_time == 0:
+ sample_time = 1;
return (sends / sample_time)

def display_iostats(self, sample_time, which):
--
2.21.3

2020-08-31 15:01:07

by Steve Dickson

Subject: Re: [PATCH] nfs-iostat: divide by zero with fresh mount

On 8/24/20 11:05 AM, Kenneth D'souza wrote:
> When an export is freshly mounted, /proc/self/mountstats displays age = 0.
> This causes nfs-iostat 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.
>
> This will prevent a backtrace like this from occurring if nfsiostat is run.
>
> nfsiostat -s 1
> Traceback (most recent call last):
> File "/usr/sbin/nfsiostat", line 662, in <module>
> iostat_command(prog)
> File "/usr/sbin/nfsiostat", line 644, in iostat_command
> print_iostat_summary(old_mountstats, mountstats, devices, sample_time, options)
> File "/usr/sbin/nfsiostat", line 490, in print_iostat_summary
> devicelist.sort(key=lambda x: stats[x].ops(time), reverse=True)
> File "/usr/sbin/nfsiostat", line 490, in <lambda>
> devicelist.sort(key=lambda x: stats[x].ops(time), reverse=True)
> File "/usr/sbin/nfsiostat", line 383, in ops
> return (sends / sample_time)
> ZeroDivisionError: float division by zero
>
> Signed-off-by: Kenneth D'souza <[email protected]>
Committed... (tag: nfs-utils-2-5-2-rc4)

steved.
> ---
> tools/nfs-iostat/nfs-iostat.py | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/tools/nfs-iostat/nfs-iostat.py b/tools/nfs-iostat/nfs-iostat.py
> index 5556f692..0c6c6dda 100755
> --- a/tools/nfs-iostat/nfs-iostat.py
> +++ b/tools/nfs-iostat/nfs-iostat.py
> @@ -383,6 +383,8 @@ class DeviceData:
> sends = float(self.__rpc_data['rpcsends'])
> if sample_time == 0:
> sample_time = float(self.__nfs_data['age'])
> + if sample_time == 0:
> + sample_time = 1;
> return (sends / sample_time)
>
> def display_iostats(self, sample_time, which):
>