** Description changed:

- ## DRAFT ###
- 
  [Impact]
  With v4.19, Linux gained extra fields in /proc/diskstats:
  
https://github.com/torvalds/linux/commit/bdca3c87fb7ad1cc61d231d37eb0d8f90d001e0c
  
  [Test Case]
  
  * Follow the procedure here:
  https://collectd.org/wiki/index.php/First_steps
  
  and make sure disk plugin is working with let's say v4.15, then move to
  >5.0 and graph will stop working, because current collectd is expecting
  a precise total of fields (14), but it is now 18:
  
  15 - discards completed successfully
  16 - discards merged
  17 - sectors discarded
  18 - time spent discarding
  
- 
  $ uname -r
  4.18.0-25-generic
  
  $ awk '{ print NF }' /proc/diskstats
  14
  
  -----
  
  $ uname -r
  5.0.0-41-generic
  
  $ awk '{ print NF }' /proc/diskstats
  18
  
  [Regression Potential]
  
+ The fix has been tested in Bionic with both a kernel lt (14 fields) and
+ gt (18 fields) than v4.19 and confirmed to work in both scenarios.
+ 
+ If a regression have to happen it will only affect and be limited to the
+ disk plugin. It won't affect any core functionnality nor other plugins.
+ 
+ The fix is found upstream for quite sometime and in Ubuntu such as 
Eoan/Focal(devel release).
+  
+ 
  [Other Informations]
  
  Upstream bug & fix:
  
  https://github.com/collectd/collectd/issues/2951
  
https://github.com/collectd/collectd/commit/6ce52f70cc1e6450df3454f19743a29295b84050
- 
https://github.com/collectd/collectd/commit/42f8dc033f5009dda7202ceee97e57bbbedf6fc3
  
  $ git describe --contains 6ce52f70cc1e6450df3454f19743a29295b84050
  collectd-5.8.1~3
  
   => collectd | 5.7.2-2ubuntu1.1 | bionic-updates/universe
   collectd | 5.8.1-1.3ubuntu1 | eoan/universe
   collectd | 5.9.2.g-1ubuntu4 | focal/universe

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https://bugs.launchpad.net/bugs/1865895

Title:
  /proc/diskstats format changes in kernel v4.19

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