[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] About the snapshot

From: Zhi Hui Li
Subject: Re: [Qemu-devel] About the snapshot
Date: Tue, 06 Dec 2011 18:01:08 +0800
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/20110617 Thunderbird/3.1.11

On 2011年12月06日 17:40, Stefan Hajnoczi wrote:
On Tue, Dec 6, 2011 at 9:07 AM, Zhi Hui Li<address@hidden>  wrote:

1) :

for example:

BDRVQcowState *s = bs->opaque;


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 ?

These two commands are unrelated.  QEMU uses the term "snapshot" for
several different features:

1. qemu-img snapshot refers to "internal snapshots" that are contained
within qcow2 image files.  The savevm/loadvm/delvm monitor commands
operate on internal snapshots.

2. qemu -snapshot refers to a temporary qcow2 image file created to
buffer any data that the guest writes.  When QEMU exits your disk
image is not modified and the temporary qcow2 file is deleted.  You
can also apply the buffer to the disk image using the "commit" monitor

yes, I understand what you say, but the qemu-img and savevm both call the function of qcow2_snapshot_create, when I use the command qemu-img snapshot ./test.qcow2 -c aa,
but the memory of the s->snapshot don't free.

in the function of

it has some "  goto fail  ";
if the function runs some times, then something makes it goto fail,
I am not sure whether it will make the refcount  incorrect.

When an error occurs its possible that refcount leaks are introduced
(the refcount was increment but will never be used), but we should
never decrement a reference that is still in use.

Please be more specific about the problem so that Kevin or I can take a look.


Ok, I got it.

thank you very much !

reply via email to

[Prev in Thread] Current Thread [Next in Thread]