IJ54044: THE 'THIN INODE' CAN BE SHARED WITH POLICY FILE.

APAR status

• Closed as program error.

Error description

• Because of the limitation in the current implementation in
  managing reserved inode pool, 'thin inode' can be shared
  erroneously with policy file while it is still assigned to the
  emergency space on the file system with SSS6K and FCM4 drives.
  This will trigger an 'assert' because of the corruption by being
  shared the same inode. And, it could also the file system
  metadata corruption by itself which will have consequence its
  own.
  

Local fix

Problem summary

• Because of the limitation in the current implementation in
  managing reserved inode pool, 'thin inode' can be shared
  erroneously with policy file while it is still assigned to the
  emergency space on the file system with SSS6K and FCM4 drives.
  This will trigger an 'assert' because of the corruption by being
  shared the same inode. And, it could also the file system
  metadata corruption by itself which will have consequence its
  own.
  

Problem conclusion

• Benefits of the solution:
  The 'thin inode' will no longer be shared.
  
  Work Around:
  None
  
  Problem trigger:
  Run 'mmchpolicy' command multiple times.
  
  Symptom:
  
  After one of the commands run, the 'thin inode' in the internal
  dump will reset to -1 indicating that the 'thin inode' is
  deallocated and 'nBlocks' will be 0 indicating the emergency
  space is deleted.[root@c145f11san04b sju]# mmfsadm dump stripe |
  egrep "State of|thin inode"State of StripeGroup "test" at
  0x18042A6A5B0, uid 7491A8C0:67D9B824, local id 1:      
  
  0: name 'system' Valid nDisks 32 nInUse 32 id 0 poolFlags 2
  thin inode 41 nBlocks 519      
  
  1: name 'data' Valid nDisks 16 nInUse 16 id 65537 poolFlags 2
  thin inode 42 nBlocks 526      
  
  2: name 'flash' Valid nDisks 8 nInUse 8 id 65538 poolFlags 2
  thin inode 43 nBlocks 526
  [root@c145f11san04b sju]# mmchpolicy test
  /home/sju/policy-default
  ...
  [root@c145f11san04b sju]# mmchmgr test c145f11san04a
  [root@c145f11san04b sju]# mmchpolicy test
  /home/sju/policy-default
  [root@c145f11san04b sju]# mmfsadm dump stripe | grep "policy
  file inode"    policy file inode: 41
  
  Platforms affected:
  Linux/AIX
  
  Functional Area affected:
  thin-provisioning
  
  Customer Impact:
  High Importance
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  SPEC SCALE STD

• Fixed component ID

  5737F33AP

Applicable component levels