[comp.sys.sun] "I'm out running around"

scottt@nosun.west.sun.com (Scott Todd) (06/12/90)

I had a truely annoying problem earlier today, Files in my network were
being temporarly replaced with files of the right length and date/time.
These files were filled with the string "I'm out running around", and were
padded to length with nulls.

I get the impression that the replacement part is a known problem with
Sun-NFS.  Can anyone out there tell me what the problem is?  And, what
causes it to be set off?

Also, I am very curious where the message "I'm out running around" comes
from.  I'm running 4.0.3c on about 40 Sun's mostly SPARC Stations and
386i's.  The main server is a 4/390.

Scott Todd
Cadre
...!sun!nosun!microcase!scottt

jayl@cs.utexas.edu (Jay Lessert) (06/13/90)

In article <8772@brazos.Rice.edu> Scott Todd writes:
>
>I had a truely annoying problem earlier today, Files in my network were
>being temporarly replaced with files of the right length and date/time.
>These files were filled with the string "I'm out running around", and were
>padded to length with nulls.

Bugid 1026933, "NFS Confused File".  Exists in SunOS 4.0.x and 4.1.

As of about a month ago, the bug and appropriate fixes were very well
understood by Sun.  A fully-QA'ed production patch for 4.0.3 is currently
scheduled to be released in July.  The same for 4.1 should be available
much sooner (maybe even now), since there are fewer (or no) other NFS
patches to be compatible with...

Grossly oversimplified (all my feeble brain is capable of understanding),
the problem is that an NFS client can become confused about whether a
given linked list of vmpages is allocated or not, and to which file.  So
the system literally reads a vmpage, thinking it contains "file1" already
in memory, when in fact that vmpage has more recently been used to write
"file2".  Oops.  Nothing wrong with the *real* contents of the file (on
disk on the server).  Our experience is that the best thing to do is
immediately reboot the client.

One thing for sure is that your NFS client has an application program that
writes the string "I'm out running around" to a file.  This application
may or may not contribute to triggering the bug.  In the hardware
configuration you mention (mostly SS1's with a single 4/390 server) there
is probably nothing you can do to prevent the bug from occurring.

Jay Lessert  {ogicse,sun,decwrl}!bit!jayl
Bipolar Integrated Technology, Inc.
503-629-5490  (fax)503-690-1498

pvo@sapphire.oce.orst.edu (Paul O'Neill) (06/14/90)

mysun% ls -alFgt | head
total 1407
-rw-rw-r--  1 pvo      pvo            23 Jun 13 20:41 .msgfile
drwxrwxr-x 12 pvo      pvo         13312 Jun 13 03:43 ./
-rw-rw-r--  1 pvo      pvo         24052 Jun 13 03:43 .newsrc
-rw-rw-r--  1 pvo      pvo           671 Jun 13 03:42 .article
-rw-rw-r--  1 pvo      pvo            31 Jun 13 03:38 .rnlast
-rw-rw-r--  1 pvo      pvo         24038 Jun 13 03:37 .newsrc.2
-rw-rw-r--  1 pvo      pvo         24052 Jun 13 03:37 .newsrc.1
-rw-------  1 pvo      pvo            61 Jun 13 00:42 dead.letter
-rw-rw-r--  1 pvo      pvo         24052 Jun 12 22:49 .oldnewsrc
mysun% cat .msgfile
I'm out running around.mysun% 
mysun% cd wrkv/calentool
/home/server/usr3/pvo/calentool
mysun% grep 'running around' *.c
calentool.c:                    fprintf(msgf, "I'm out running around.");
mysun% 

.msgfile is used by the `nlock' screenlocking program.

Other than this, how do you like calentool?   (It took me 6 months to find
this one.  At first I thought it was a worm or virus!   :-)

Paul O'Neill                 pvo@oce.orst.edu
Coastal Imaging Lab
OSU--Oceanography
Corvallis, OR  97331         503-737-3251