Bug 236277 - direct I/O locking confused dlm
direct I/O locking confused dlm
Status: CLOSED DUPLICATE of bug 234086
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
medium Severity medium
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Assigned To: David Teigland
Red Hat Kernel QE team
Depends On:
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Reported: 2007-04-12 16:07 EDT by Nate Straz
Modified: 2009-09-03 12:51 EDT (History)
1 user (show)

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Doc Type: Bug Fix
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Last Closed: 2007-04-19 09:50:10 EDT
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Description Nate Straz 2007-04-12 16:07:13 EDT
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:
Actual results:

Expected results:

Additional info:
Comment 1 David Teigland 2007-04-19 09:50:10 EDT

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

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