kern/48426: nfsstat shows negative counts

[oster%netbsd.org@localhost]

>Number:         48426
>Category:       kern
>Synopsis:       nfsstat shows negative counts
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Dec 06 20:40:00 +0000 2013
>Originator:     Greg Oster
>Release:        NetBSD 6.1.2
>Organization:
>Environment:
        
        
System: NetBSD mickey 6.1.2 NetBSD 6.1.2 (QUAD) #0: Thu Sep 26 15:35:44 CST 
2013 
oster@quad:/u1/builds/build242/src/obj/amd64/u1/builds/build242/src/sys/arch/amd64/compile/QUAD
 amd64
Architecture: x86_64
Machine: amd64
>Description:

nfsstat shows negative count values.  For example:

Client Info:
RPC Counts: (176595266 calls)
      null         getattr         setattr          lookup          access
         0  0%    96191690 54%      694127  0%    28335421 16%     5543767  3%
  readlink            read           write          create           mkdir
      1348  0%     2769302  1%    26090532 14%      666888  0%       15792  0%
   symlink           mknod          remove           rmdir          rename
       615  0%           2  0%      281455  0%       15681  0%      446339  0%
      link         readdir     readdirplus          fsstat          fsinfo
      6326  0%      666711  0%           0  0%    13574917  7%           5  0%
  pathconf          commit
     36406  0%     1257942  0%
RPC Info:
   timeout         invalid      unexpected         retries        requests
         1               0               2              17       176595266
Cache Info:
 attrcache     lookupcache            read           write        readlink
-153914704 293%   269765890 90%  -841091842 100%    40898680 71%    18241964 99%
   readdir     direofcache
   5236935 90%     1339656 65%

Server Info:
RPC Counts: (1 call)
      null         getattr         setattr          lookup          access
         1 100%           0  0%           0  0%           0  0%           0  0%
  readlink            read           write          create           mkdir
         0  0%           0  0%           0  0%           0  0%           0  0%
   symlink           mknod          remove           rmdir          rename
         0  0%           0  0%           0  0%           0  0%           0  0%
      link         readdir     readdirplus          fsstat          fsinfo
         0  0%           0  0%           0  0%           0  0%           0  0%
  pathconf          commit
         0  0%           0  0%
Server Errors:
RPC errors          faults
         0               0
Server Cache Stats:
inprogress            idem        non-idem          misses
         0               0               0               1
Server Write Gathering:
    writes       write RPC       OPs saved
         0               0               0  0%


>How-To-Repeat:

        Run /usr/bin/nfsstat on a NetBSD 6.1.2 NFS client that has
been doing a fair bit of activity.  It is expected that this problem
exists in -current as well, but my test box needs to transfer a lot
more data before the counters overflow and that can be confirmed.

>Fix:

        As David Holland suggests, making 'struct nfsstats' use
something larger than integers for counters would be a good first
step.


>Unformatted: