[LU-9783] fiemap deadlock Created: 19/Jul/17  Updated: 19/Jul/17  Resolved: 19/Jul/17

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

Type: Bug Priority: Minor
Reporter: Andriy Skulysh Assignee: WC Triage
Resolution: Duplicate Votes: 0
Labels: None

Severity: 3
Rank (Obsolete): 9223372036854775807

 Description   

It is a side effect of LU-3219. When fiemap is used with FIEMAP_FLAG_SYNC flag OST locks spare regions one by one. It may lead to a deadlock with another client which tries to get write lock on a region covering 2 spare regions.
So scenario is following :
1) client 1 calls fiemap, OST locks first spare region
2) client 2 enqueues PW lock on whole file, it conflicts with first spare region
3) OST tries to lock second spare region, but it conflicts with PW waiting lock.

 Comments   
Comment by Gerrit Updater [ 19/Jul/17 ]

Andriy Skulysh (andriy.skulysh@seagate.com) uploaded a new patch: https://review.whamcloud.com/28101
Subject: LU-9783 ofd: fiemap deadlock
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 931fced5e621698f69955a4c14ec395d1a25bd97

Comment by Andriy Skulysh [ 19/Jul/17 ]

Please ignore this bug, the fix was submitted earlier in LU-9543

Comment by Peter Jones [ 19/Jul/17 ]

ok - thanks Andriy!

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