[LU-8650] DNE disabled REP-ACK Created: 29/Sep/16  Updated: 16/May/17  Due: 29/Oct/16  Resolved: 09/May/17

Status: Resolved
Project: Lustre
Component/s: None
Affects Version/s: Lustre 2.8.0
Fix Version/s: Lustre 2.10.0

Type: Bug Priority: Critical
Reporter: Lai Siyao Assignee: Lai Siyao
Resolution: Fixed Votes: 0
Labels: None

Issue Links:
Related
is related to LU-9504 LBUG ptlrpc_handle_rs()) ASSERTION( l... Resolved
Severity: 3
Rank (Obsolete): 9223372036854775807

 Description   

LU-7903 reveals that REP-ACK is disabled in 2.8, this was introduced in LU-3538 http://review.whamcloud.com/#/c/12530/, which is to support DNE Commit-on-Sharing, but it disabled REP-ACK, while Commit-on-Sharing doesn't take effect for local operations (operation which involves only one MDT) either, this may cause single MDT recovery fail.

To fix this, we need to enable REP-ACK, and also make sure http://review.whamcloud.com/#/c/12530/ work as designed. The implementation will be like this:
1. save local locks upon unlock as before, but don't convert locks into COS mode.
2. reply_out_callback() wakes up ptlrpc_handle_rs(), if reply is not committed yet, convert locks into COS mode, otherwise decref locks like before.
3. later when the operation is committed, ptlrpc_commit_replies() wakes up ptlrpc_handle_rs() again, which will decref locks like before.



 Comments   
Comment by Gerrit Updater [ 29/Sep/16 ]

Lai Siyao (lai.siyao@intel.com) uploaded a new patch: http://review.whamcloud.com/22807
Subject: LU-8650 mdt: enable REP-ACK for DNE
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: b21a27b28be8aaca657733f1fb2e845e394885ef

Comment by Oleg Drokin [ 04/Oct/16 ]

So does this affect single MDT installs too? Or is this DNE only?

Comment by Lai Siyao [ 07/Oct/16 ]

This won't affect single MDT installs, because it disabled REP-ACK when Sync-on-Lock-Cancel is enabled, which is set on DNE only.

Comment by Gerrit Updater [ 09/May/17 ]

Oleg Drokin (oleg.drokin@intel.com) merged in patch https://review.whamcloud.com/22807/
Subject: LU-8650 mdt: enable REP-ACK for DNE
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 6dc05f00218798e400433feeda7ad6f271b535d8

Comment by Peter Jones [ 09/May/17 ]

Landed for 2.10

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