Bug 744071

Summary: virsh snapshot-edit can't edit disk snapshots
Product: Red Hat Enterprise Linux 6 Reporter: Eric Blake <eblake>
Component: libvirtAssignee: Eric Blake <eblake>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 6.2CC: acathrow, eblake, mjenner, veillard, weizhan
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: libvirt-0.9.4-16.el6 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-12-06 11:37:10 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 638510    
Bug Blocks: 747120    

Description Eric Blake 2011-10-06 21:45:47 UTC 
Description of problem:
Creating a disk snapshot with <disks> fails if VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY was not specified, although this should not be required if VIR_DOMAIN_SNAPSHOT_CREATE_REDEFINE is present.

Version-Release number of selected component (if applicable):
libvirt-0.9.4-14.el6

How reproducible:
100%

Steps to Reproduce:
1. virsh start dom
2. virsh snapshot-create-as dom --disk-only snap
3. virsh snapshot-edit dom snap # try adding <description>
  
Actual results:
error: Failed to update snap
error: argument unsupported: unable to handle disk requests in snapshot

Expected results:
While --disk-only is important for allowing <disks> when creating a new snapshot, modifying an existing snapshot should be smart enough to realize that it already existed with disks, and thus not error out.

This needs to be fixed in both the qemu driver (avoid erroring out on redefine) and in virsh (communicating to 0.9.5 or 0.9.6 will encounter qemu that errors out, so virsh must scrape the xml and decide whether to add the disk-only flag).

Additional info:
Introduced by the resolution to bug 638510
Comment 1 Eric Blake 2011-10-06 23:19:54 UTC 
Upstream patches proposed:
https://www.redhat.com/archives/libvir-list/2011-October/msg00196.html
Comment 2 Eric Blake 2011-10-07 14:47:44 UTC 
In POST:
http://post-office.corp.redhat.com/archives/rhvirt-patches/2011-October/msg00236.html
Comment 5 weizhang 2011-10-08 06:41:02 UTC 
verify pass on
qemu-kvm-0.12.1.2-2.195.el6.x86_64
kernel-2.6.32-206.el6.x86_64
libvirt-0.9.4-16.el6.x86_64


# virsh snapshot-edit qcow2 snap
Snapshot snap edited.
Comment 6 errata-xmlrpc 2011-12-06 11:37:10 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2011-1513.html