#9972 NORM Not Tri: openfirmware writes fail on an ext2 filesystem of certain size range

[Zarro Boogs per Child]

#9972: openfirmware writes fail on an ext2 filesystem of certain size range
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           Reporter:  Quozl                |       Owner:  wmb at firmworks.com
               Type:  defect               |      Status:  assigned         
           Priority:  normal               |   Milestone:  Not Triaged      
          Component:  ofw - open firmware  |     Version:  not specified    
         Resolution:                       |    Keywords:                   
        Next_action:  never set            |    Verified:  0                
Deployment_affected:                       |   Blockedby:                   
           Blocking:                       |  
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Changes (by wmb at firmworks.com):

  * status:  new => assigned


Comment:

 The problem is EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER

 In "classic" ext2, every block group contained a backup copy of the
 superblock and the group descriptors.  With SPARSE enabled, only groups 0,
 1, and powers of 3, 5, and 7 have backup copies.

 OFW was trying to write backups to every group, and in doing so, overwrote
 inode bitmaps for those groups that should not have backups.

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Ticket URL: <http://dev.laptop.org/ticket/9972#comment:3>
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