Re: [Qemu-devel] About the snapshot

[Stefan Hajnoczi <stefanha@gmail.com>]

2011/12/6 Zhi Hui Li <zhihuili@linux.vnet.ibm.com>:
>
>
> 2011/12/6 Stefan Hajnoczi <stefanha@gmail.com>
>>
>> On Tue, Dec 6, 2011 at 10:01 AM, Zhi Hui Li <zhihuili@linux.vnet.ibm.com>
>> wrote:
>> > On 2011年12月06日 17:40, Stefan Hajnoczi wrote:
>> >>
>> >> On Tue, Dec 6, 2011 at 9:07 AM, Zhi Hui Li<zhihuili@linux.vnet.ibm.com>
>> >>  wrote:
>> >>>
>> >>>
>> >>> 1) :
>> >>>
>> >>> for example:
>> >>>
>> >>> BDRVQcowState *s = bs->opaque;
>> >>>
>> >>> s->snapshots
>> >>> s->nb_snapshots
>> >>>
>> >>>
>> >>> 1:use the command:   qemu-img snapshot ./test.qcow2  -c aa
>> >>> the memory of the s->snapshot don't free,
>> >>> if the s->nb_snapshots is large, Does it have some problems.
>> >>>
>> >>> 2: use the command:  qemu-system-x86_64  ./test.qcow2 -snapshot
>> >>> when the program ends, Does it need to free the s->snapshots ?
>> >>
>> Okay, I think you're saying that in #1 s->snapshots is leaked because
>> qcow2_free_snapshots() is not being called from qcow2_close().
>>
>> Do you want to send a patch to fix this?
>
>
> Ok, I will send a patch  tomorrow.
> But I think in the #2  it also need to call qcow2_free_snapshots() , if you
> have called several times savevm,
> the s->snapshots will very large, when the process end, it also need to
> free.

Right, I think I understand what you're saying.  I was thinking about
what #1 and #2 mean differently, but it doesn't matter.

If qcow2_close() frees s->snapshots then the problem is solved in all
possible qcow2 use cases, including #2 with savevm.

Stefan