Bug 481027

Summary: backport the fix to the misordered write bug in dm-exception-store.c to the next RHEL4/RHEL5 updates
Product: Red Hat Enterprise Linux 5 Reporter: luping.nju
Component: device-mapperAssignee: LVM and device-mapper development team <lvm-team>
Status: CLOSED DUPLICATE QA Contact: Cluster QE <mspqa-list>
Severity: medium Docs Contact:
Priority: low    
Version: 5.3CC: agk, christophe.varoqui, dwysocha, egoggin, heinzm, iannis, jbrassow, junichi.nomura, kueda, lmb, mbroz, prockai, tranlan
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2010-06-23 15:23:37 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description luping.nju 2009-01-21 19:43:34 UTC 
Description of problem:

In dm-exception-store.c, when a metatdata chunk is filled in, the code firstly write to disk the current metadata chunk and then zero out the next metadata chunk. This could end up with a inconsistent exception data structure on disk if there is a power outage / kernel crash coming in between the two writes.

The bug has actually been fixed in the current mainstream kernel by Mikulas Patocka. See the following link:

http://lkml.indiana.edu/hypermail/linux/kernel/0810.3/0020.html

But I am not sure if it's going to be in the next RHEL4/RHEL5 updates. So here I am requesting to have this included in the next updates.

Version-Release number of selected component (if applicable):

It exists on all the stable RHEL4/RHEL5 releases

How reproducible:

It's hard to reproduce in real life, but we can certainly simulate this by manually put a "die" in between the two writes.

Additional info:
Comment 2 Milan Broz 2010-06-23 15:23:37 UTC 

*** This bug has been marked as a duplicate of bug 496102 ***