Bug 587605

Summary:	Failed to re-base qcow2 snapshot
Product:	Red Hat Enterprise Linux 5	Reporter:	Qunfang Zhang <qzhang>
Component:	kvm	Assignee:	Virtualization Maintenance <virt-maint>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	high	Docs Contact:
Priority:	high
Version:	5.6	CC:	ehabkost, kwolf, lihuang, llim, mjenner, ndai, tburke, virt-maint, ykaul
Target Milestone:	rc	Keywords:	Regression
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kvm-83-180.el5	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-01-13 23:35:18 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 Qunfang Zhang 2010-04-30 11:19:38 UTC

Description of problem:
Install a RHEL5.5-64 guest and create snapshot chains
Base image (RHEL5.5-64.qcow2) -- > sn1 --> sn2 --> sn3 --> sn4 --> sn5

Then rebase sn2 to base image, failed.
#qemu-img rebase -b sn3 -F qcow2 -f qcow2 sn5

Version-Release number of selected component (if applicable):
kvm-83-172.el5
2.6.18-194.el5

How reproducible:
100%

Steps to Reproduce:
1.Install a rhel5.5-64 qcow2 format image and create snapshot chain.
2.Rebase snapshot
3.
  
Actual results:
#qemu-img rebase -b sn3 -F qcow2 -f qcow2 sn5
qemu-img: Error while writing to COW image: Permission denied

Expected results:
Rebase successfully.

Additional info:

Comment 1 Kevin Wolf 2010-04-30 12:02:55 UTC

Does this work with 170? Looks like it's related to Naphtali's read-only support which was added in 171. Adding him to CC.

Comment 2 Qunfang Zhang 2010-05-04 05:19:28 UTC

Re-test in kvm-170, and this issue does not exist.

This time I only create sn1,sn2 and sn3, write some file in each snapshot, and then rebase sn3 to sn1.
# qemu-img rebase -b sn1 -F qcow2 -f qcow2 sn3

in kvm-170:
# qemu-img rebase -b sn1 -F qcow2 -f qcow2 sn3
# qemu-img info sn3
image: sn3
file format: qcow2
virtual size: 80G (85899345920 bytes)
disk size: 230M
cluster_size: 65536
backing file: sn1 (actual path: sn1)

in kvm-172:
[root@localhost ~]# qemu-img rebase -b sn1 -F qcow2 -f qcow2 sn3
qemu-img: Error while writing to COW image: Permission denied

Comment 8 Qunfang Zhang 2010-05-14 07:00:30 UTC

Verified on kvm-83-180.el5, passed.

Comment 10 Qunfang Zhang 2010-11-02 06:31:29 UTC

Verified on kvm-83-207.el5, host install tree: RHEL5.6-Server-20101029.0, with the steps in bug description. passed.
So, I will change the status to VERIFIED.

Comment 12 errata-xmlrpc 2011-01-13 23:35:18 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-2011-0028.html