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Bug 236277

Summary: direct I/O locking confused dlm
Product: Red Hat Enterprise Linux 5 Reporter: Nate Straz <nstraz>
Component: kernelAssignee: David Teigland <teigland>
Status: CLOSED DUPLICATE QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: medium    
Version: 5.0CC: cluster-maint
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
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Clone Of: Environment:
Last Closed: 2007-04-19 13:50:10 UTC Type: ---
Regression: --- Mount Type: ---
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Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description Nate Straz 2007-04-12 20:07:13 UTC 
Description of problem:

We were running a simultaneous streaming direct I/O test case on two nodes, kool
and salem.  The dd ran on salem, but kool didn't make any progress.  After
killing the dd on salem, the dd on kool remained stuck.  Here is the relevant
output from debugfs.

Kool (node 4):
Resource ffff81005faec0c0 Name (len=24) "       2             40a"  
Local Copy, Master is node 5
Granted Queue
Conversion Queue
01550021 PR (CW) Master:     02dc0022
Waiting Queue


Salem (node 5):
Resource ffff81006628ac80 Name (len=24) "       2             40a"  
Master Copy
Granted Queue
02960031 CW
Conversion Queue
02dc0022 NL (CW) Remote:   4 01550021
Waiting Queue

Test case:
1. create file which is 1/2 of memory.

dd if=/dev/urandom bs=1024k count=1024 of=largefile

2. on both nodes, read the file until the I/O speed stabalizes.

for i in `seq 10`; do dd if=largefile of=/dev/null bs=4k; done

3. on both nodes, read the file with direct I/O
for i in `seq 10`; do dd if=largefile of=/dev/null bs=4k iflag=direct; done


Version-Release number of selected component (if applicable):
2.6.21-rc6 + gfs from CVS HEAD

How reproducible:


Steps to Reproduce:
1.
2.
3.
  
Actual results:


Expected results:


Additional info:
Comment 1 David Teigland 2007-04-19 13:50:10 UTC 

*** This bug has been marked as a duplicate of 234086 ***