Bug 587605 - Failed to re-base qcow2 snapshot
Summary: Failed to re-base qcow2 snapshot
Alias: None
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kvm
Version: 5.6
Hardware: All
OS: Linux
Target Milestone: rc
: ---
Assignee: Virtualization Maintenance
QA Contact: Virtualization Bugs
Depends On:
TreeView+ depends on / blocked
Reported: 2010-04-30 11:19 UTC by Qunfang Zhang
Modified: 2013-01-09 22:31 UTC (History)
9 users (show)

Fixed In Version: kvm-83-180.el5
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2011-01-13 23:35:18 UTC
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2011:0028 0 normal SHIPPED_LIVE Low: kvm security and bug fix update 2011-01-13 11:03:39 UTC

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):

How reproducible:

Steps to Reproduce:
1.Install a rhel5.5-64 qcow2 format image and create snapshot chain.
2.Rebase snapshot
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.


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