#10140 NORM Not Tri: External device large Journal does not display

[Zarro Boogs per Child]

#10140: External device large Journal does not display
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           Reporter:  mikus             |       Owner:  tomeu                            
               Type:  defect            |      Status:  new                              
           Priority:  normal            |   Milestone:  Not Triaged                      
          Component:  journal-activity  |     Version:  Development build as of this date
         Resolution:                    |    Keywords:                                   
        Next_action:  never set         |    Verified:  0                                
Deployment_affected:                    |   Blockedby:                                   
           Blocking:                    |  
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Comment(by Quozl):

 Technical analysis; not a request for comment or a reply to the reported
 issue.

 Reviewed the system dump.  The dump is valid given the uptime 1:31; it is
 not post-reboot.  The filesystem /media/CAVE is mounted.  This system has
 ample swap space, so a memory depletion issue is unlikely.  There was
 nothing in dmesg to suggest a memory depletion issue.  The sugar-session
 process (2139) showed a VmPeak of 60328 kB, compared with a typical
 startup VmPeak value of 44268 kB.

 sugar/shell.log shows a recursion loop may have been entered; the media
 contains a path, of
 /media/CAVE/olpc/isolation/1/uid_to_home_dir/10015/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/instance/tmp
 for which permission was denied.

 sugar/shell.log first reference to /media/CAVE was at 1283514412, and the
 last timestamp in the log was at 1283519777, an offset of 89 minutes,
 which is entirely consistent with the uptime.

 Diagnosis: the journal is continuing to read the media while exploring an
 infinite filesystem loop caused by symbolic links.

 Interim conclusion: the journal scan logic should be taught to avoid
 infinite loops.  If there is logic already present, then it is failing to
 trigger on the subject filesystem.  The journal scan logic might also be
 taught to avoid scanning filesystems that contain more than a usual amount
 of files.

 Reviewed the earlier system dump from four months ago.  No evidence of
 filesystem infinite loop, but sugar/shell.log does show ''permission
 denied'' and ''no such file or directory errors'' reading the target
 media.

 Alternate diagnosis: any error reading the target media might cause this
 symptom.  This is testable.

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Ticket URL: <http://dev.laptop.org/ticket/10140#comment:2>
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