[LU-17871] FLOCK ownlocks may be not set

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Labels: LTS15
• Severity: 3
• Assignee: Andriy Skulysh
• Reporter: Andriy Skulysh

Description

Fixes LUS-10623/ LU-15402 ldlm: speedup RD flock enqueue

The fix helps to avoid following kernel panic:

[1751308.091508] LustreError: 19554:0:(ldlm_flock.c:234:ldlm_flock_deadlock()) ASSERTION( req != lock ) failed: 
[1751308.095644] LustreError: 19554:0:(ldlm_flock.c:234:ldlm_flock_deadlock()) LBUG 
[1751308.097405] Pid: 19554, comm: mdt03_004 4.18.0-477.27.1.el8_lustre.ddn17.x86_64 #1 SMP Tue Apr 9 21:59:53 UTC 2024 
[1751308.101036] Call Trace TBD: 
[1751308.102285] [<0>] libcfs_call_trace+0x6f/0xa0 [libcfs]
[1751308.103518] [<0>] lbug_with_loc+0x3f/0x70 [libcfs]
[1751308.104824] [<0>] ldlm_flock_deadlock.isra.10+0x1b4/0x200 [ptlrpc]
[1751308.106324] [<0>] ldlm_process_flock_lock+0x287/0x1ee0 [ptlrpc]
[1751308.107768] [<0>] ldlm_lock_enqueue+0x253/0xaa0 [ptlrpc]
[1751308.109024] [<0>] ldlm_handle_enqueue0+0x61a/0x16d0 [ptlrpc]
[1751308.110340] [<0>] tgt_enqueue+0xa4/0x200 [ptlrpc]
[1751308.111507] [<0>] tgt_request_handle+0xc9c/0x1960 [ptlrpc]
[1751308.112820] [<0>] ptlrpc_server_handle_request+0x323/0xbd0 [ptlrpc]
[1751308.114266] [<0>] ptlrpc_main+0xbf7/0x1510 [ptlrpc]
[1751308.115445] [<0>] kthread+0x134/0x150
[1751308.116363] [<0>] ret_from_fork+0x1f/0x40
[1751308.117393] Kernel panic - not syncing: LBUG  

Issue Links

• is duplicated by: LU-18071 Single client job -o flock zombie flock remains on file, -o local flock works fine

Comments

[Yang Sheng]

Could you please explain why ownlock can impact ldlm_flock_deadlock? It is really a issue while the ownlock not set, But i don't think it will trigger LBUG in ldlm_flock_deadlock. They are totally unrelated.

[Peter Jones]

Merged for 2.16

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/c/fs/lustre-release/+/55184/
Subject: LU-17871 ldlm: FLOCK ownlocks may be not set
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: ede8d928d6c47551371512c80dfa4f159260e7e2

[Gerrit Updater]

"Andriy Skulysh <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/c/fs/lustre-release/+/55184
Subject: LU-17871 ldlm: FLOCK ownlocks may be not set
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 8fdbca934b47560bbfc70e876944f18fe6d28864