IJ25652: DATA INTEGRITY ISSUE DUE TO RACE CONDITION BETWEEN TRACK WRITE AND METADATA FLUSH OPERATION

APAR status

• Closed as program error.

Error description

• Cannot commit some log records successfully.
  But it might have updated the VtrackMap.
  Due to the resign, update to the
  memory metadata may not have
  happened.  In such a scenario,
  if another thread is trying to do
  a VtrackMap flush operation it
  successfully writes the Metadata
  block, then the metadata version
  updated by the VtrackMap entry
  and Metadata block will be the
  same, although the log will
  contain the latest version
  of the record.
  

Local fix

Problem summary

• Cannot commit some log records successfully.
  But it might have updated the VtrackMap.
  Due to the resign, update to the
  memory metadata may not have
  happened.  In such a scenario,
  if another thread is trying to do
  a VtrackMap flush operation it
  successfully writes the Metadata
  block, then the metadata version
  updated by the VtrackMap entry
  and Metadata block will be the
  same, although the log will
  contain the latest version
  of the record.
  

Problem conclusion

•  Benefits of the solution:  
  This fix will help to avoid skipping log replay.
  Work around: NA
  Problem trigger:
  A RG resign during a track write operation
  Symptom:  Error output/message
  Platforms affected: ALL Linux OS environments
  Functional Area affected: ESS/GNR
  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:

  IJ25859

Fix information

• Fixed component name

  SPEC SCALE STD

• Fixed component ID

  5737F33AP

Applicable component levels