Re: [Qemu-devel] [PATCH v2 1/1] Add QMP bits for blockdev-snapshot-sync.

[Kevin Wolf]

Am 28.04.2011 15:21, schrieb Jes Sorensen:
> On 04/27/11 17:05, Luiz Capitulino wrote:
>>> +If a new image file is specified, the new image file will become the
>>>> +new root image. If format is specified, the snapshot file will be
>>>> +created in that format. Otherwise the snapshot will be internal!
>>>> +(currently unsupported).
>> Sorry for the stupid question, but what's a "new root image"? Also, all
>> these assumptions seem human features to me, as it can save some typing
>> and I can poke around to see where the snapshots are stored.
>>
>> All arguments should be mandatory in QMP, IMO.
> 
> Sorry, but there is absolutely no reason to make all arguments
> mandatory. Sure it can be done, but the only result is a separate
> handling function for it, so we got more almost identical, but still
> different code to maintain.
> 
>> Finally, what's the expect behavior when -snapshot is used? I'm getting
>> this:
>>
>>  (qemu) snapshot_blkdev ide0-hd0 snap-test
>>  Could not open '/tmp/vl.6w8YXA'
>>  (qemu)
> 
> What type of file system is your /tmp? You need to provide full path to
> the snapshot file if you don't want it created next to where your qemu
> binary is being executed.

I think the problem is that this is a temporary file, i.e. unlinked
directly after it has been opened. Trying to reopen a deleted file is a
bad idea.

Kevin