Looks like this is fixed in master.
commit af957387547b05ed6dc4d84c10cca42700a7aeda
Author: Zhang Haoyu <zhan...@sangfor.com>
Date: Mon Sep 29 16:38:02 2014 +0800
snapshot: fix referencing wrong variable in while loop in do_delvm
The while loop variabal is "bs1",
but "bs" is always passed to bdrv_snapshot_delete_by_id_or_name.
Broken in commit a89d89d, v1.7.0.
On Tue, Jul 14, 2015 at 12:32 AM, Marcus <shadow...@gmail.com> wrote:
> Ok, I seem to have fixed it. I can submit a patch, but some input would be
> appreciated. In savevm.c, we have two functions:
>
> void hmp_delvm(Monitor *mon, const QDict *qdict), which my libvirt is
> using
>
> static int del_existing_snapshots(Monitor *mon, const char *name)
>
>
> These look to have the same origins. My guess was that perhaps the hmp
> version was first, and the second was a copy for QMP, or perhaps vice
> versa. At any rate, I changed hmp_delvm to call del_existing_snapshots:
>
> void hmp_delvm(Monitor *mon, const QDict *qdict)
>
> {
>
> const char *name = qdict_get_str(qdict, "name");
>
> del_existing_snapshots(mon, name);
>
> }
>
> And the issue went away. My only concern with this is that hmp_delvm does
> a slightly different thing, it first calls find_vmstate_bs() which seems
> to check if the block devices support snapshots. del_existing_snapshots
> does this slightly differently. If I can get feedback on that I'd
> appreciate it. Also, I'll look around for patch submission guidelines, but
> if someone can point me in the right direction I'd appreciate it as well.
>
> Thanks
>
>
>
> On Mon, Jul 13, 2015 at 11:29 PM, Marcus <shadow...@gmail.com> wrote:
>
>> Ok, this is weird. It looks like it dies on the first disk, which is the
>> only one that actually gets its snapshot removed. Perhaps it is processing
>> the first disk a second time?
>>
>> # virsh qemu-monitor-command i-2-38-VM --hmp 'delvm 1'
>>
>> Error while deleting snapshot on device 'virtio-disk0': Can't find the
>> snapshot
>>
>> On Mon, Jul 13, 2015 at 10:28 PM, Marcus <shadow...@gmail.com> wrote:
>>
>>> Hi all,
>>>
>>> I've recently been toying with VM snapshots, and have ran into an
>>> issue. Given a VM with multiple disks, it seems a snapshot-create followed
>>> by a snapshot-delete will only remove the qcow2 snapshot for the first disk
>>> (or perhaps just the disk that contains the memory), not all of the disk
>>> snapshots it created. Is this something people are aware of?
>>>
>>> In searching around, I found a bug report where snapshot-creates
>>> would fail due to the qcow2 snapshot ids being inconsistent. That looks
>>> like it is patched for 2.4 qemu (
>>> http://lists.nongnu.org/archive/html/qemu-devel/2015-03/msg04963.html),
>>> this bug would trigger that one by leaving IDs around that are inconsistent
>>> between member disks, but is not the same.
>>>
>>> At first I was snooping around the libvirt lists looking for an
>>> answer, but found in the code that they're simply calling the qemu monitor
>>> to handle snapshot deletes on active VMs.
>>>
>>> # virsh snapshot-create 7
>>>
>>> Domain snapshot 1436792720 created
>>>
>>>
>>> # virsh snapshot-list 7
>>>
>>> Name Creation Time State
>>>
>>> ------------------------------------------------------------
>>>
>>> 1436792720 2015-07-13 06:05:20 -0700 running
>>>
>>>
>>> # virsh domblklist 7
>>>
>>> Target Source
>>>
>>> ------------------------------------------------
>>>
>>> vda
>>> /mnt/2a270ef3-f389-37a4-942f-380bed9f70aa/e4d6e885-1382-40bc-890b-ad9c8b51a7a5
>>>
>>> vdb
>>> /mnt/2a270ef3-f389-37a4-942f-380bed9f70aa/7033e4c6-5f59-4325-b7e0-ae191e12e86c
>>>
>>>
>>> # qemu-img snapshot -l
>>> /mnt/2a270ef3-f389-37a4-942f-380bed9f70aa/e4d6e885-1382-40bc-890b-ad9c8b51a7a5
>>>
>>> Snapshot list:
>>>
>>> ID TAG VM SIZE DATE VM CLOCK
>>>
>>> 1 1436792720 173M 2015-07-13 06:05:20 00:01:10.938
>>>
>>>
>>> # qemu-img snapshot -l
>>> /mnt/2a270ef3-f389-37a4-942f-380bed9f70aa/7033e4c6-5f59-4325-b7e0-ae191e12e86c
>>>
>>> Snapshot list:
>>>
>>> ID TAG VM SIZE DATE VM CLOCK
>>>
>>> 1 1436792720 0 2015-07-13 06:05:20 00:01:10.938
>>>
>>>
>>> # virsh snapshot-delete 7 1436792720
>>>
>>> Domain snapshot 1436792720 deleted
>>>
>>>
>>> # qemu-img snapshot -l
>>> /mnt/2a270ef3-f389-37a4-942f-380bed9f70aa/e4d6e885-1382-40bc-890b-ad9c8b51a7a5
>>>
>>> # qemu-img snapshot -l
>>> /mnt/2a270ef3-f389-37a4-942f-380bed9f70aa/7033e4c6-5f59-4325-b7e0-ae191e12e86c
>>>
>>> Snapshot list:
>>>
>>> ID TAG VM SIZE DATE VM CLOCK
>>>
>>> 1 1436792720 0 2015-07-13 06:05:20 00:01:10.938
>>>
>>
>>
>
