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Bug 639412

Summary:	block: must prevent merges of discard and write requests [rhel-6.0.z]
Product:	Red Hat Enterprise Linux 6	Reporter:	RHEL Program Management <pm-rhel>
Component:	kernel	Assignee:	Frantisek Hrbata <fhrbata>
Status:	CLOSED ERRATA	QA Contact:	Gris Ge <fge>
Severity:	urgent	Docs Contact:
Priority:	urgent
Version:	6.1	CC:	bdonahue, chellwig, coughlan, dhoward, fge, fhrbata, jmoyer, jpirko, kzhang, msnitzer, mzywusko, pcfe, pm-eus, qcai, snagar, syeghiay, vgoyal, yugzhang
Target Milestone:	rc	Keywords:	ZStream
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel-2.6.32-71.3.1.el6	Doc Type:	Bug Fix
Doc Text:	Previously, a write request may have merged with a discard request. This could have posed a potential risk for 3rd party drivers which could possibly issue a discard without waiting properly. With this update, discarding of write block I/O requests by preventing merges of discard and write requests in one block I/O has been introduced, thus, resolving the possible risks.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2010-11-10 19:10:43 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:
Bug Depends On:	637805
Bug Blocks:

Description RHEL Program Management 2010-10-01 17:05:23 UTC

This bug has been copied from bug #637805 and has been proposed
to be backported to 6.0 z-stream (EUS).

Comment 2 Frantisek Hrbata 2010-10-04 07:14:37 UTC

in 2.6.32-71.3.1.el6

Comment 5 Barry Donahue 2010-10-21 14:58:06 UTC

The bug was found upstream and there is no reproducible test case.

Comment 7 errata-xmlrpc 2010-11-10 19:10:43 UTC

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2010-0842.html

Comment 8 Martin Prpič 2010-11-11 11:55:06 UTC

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Previously, a write request may have merged with a discard request. This could have posed a potential risk for 3rd party drivers which could possibly issue a discard without waiting properly. With this update, discarding of write block I/O requests by preventing merges of discard and write requests in one block I/O has been introduced, thus, resolving the possible risks.