Am 09.01.2019 um 15:27 hat Max Reitz geschrieben: > On 09.01.19 15:21, Kevin Wolf wrote: > > Am 09.01.2019 um 15:10 hat Max Reitz geschrieben: > >> On 06.09.18 13:11, Daniel Henrique Barboza wrote: > >>> changes in v2: > >>> - removed the "RFC" marker; > >>> - added a new patch (patch 2) that removes > >>> bdrv_snapshot_delete_by_id_or_name from the code; > >>> - made changes in patch 1 as suggested by Murilo; > >>> - previous patch set link: > >>> https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg04658.html > >>> > >>> > >>> It is not uncommon to see bugs being opened by testers that attempt to > >>> create VM snapshots using HMP. It turns out that "0" and "1" are quite > >>> common snapshot names and they trigger a lot of bugs. I gave an example > >>> in the commit message of patch 1, but to sum up here: QEMU treats the > >>> input of savevm/loadvm/delvm sometimes as 'ID', sometimes as 'name'. It > >>> is documented as such, but this can lead to strange situations. > >>> > >>> Given that it is strange for an API to consider a parameter to be 2 fields > >>> at the same time, and inadvently treating them as one or the other, and > >>> that removing the ID field is too drastic, my idea here is to keep the > >>> ID field for internal control, but do not let the user set it. > >>> > >>> I guess there's room for discussion about considering this change an API > >>> change or not. It doesn't affect users of HMP and it doesn't affect > >>> Libvirt, > >>> but simplifying the meaning of the parameters of savevm/loadvm/delvm. > >> > >> (Yes, very late reply, I'm sorry...) > >> > >> I do think it affects users of HMP, because right now you can delete > >> snapshots with their ID, and after this series you cannot. > > > > Can there be snapshots that can't be identified by a snapshot name, but > > only by their ID? > > I don't know, but what I meant is that if you have scripts to do all > this, you might have to adjust them with this change.
That's what the H in HMP means. > >> I think we had a short discussion about just disallowing numeric > >> snapshot names. How bad would that be? > > > > It would be incompatible with existing images and result in a more > > complex snapshot identifier resolution. Why would it be any better? > > It wouldn't be incompatible with existing images if we'd just disallow > creating such snapshots. I don't see how the identifier resolution > would be more complex. > > I don't know if it'd be better. I'd just find it simpler (for us, that > is -- for users, I'm not sure). Identifier resolution A: - Find a snapshot that has the given identifier as a name - If no such snapshot exists, it is an error Identifier resolution B: - If the identifier is a number, find a snapshot that has the given identifier as its ID - If the identifier is not a number, find a snapshot that has the given identifier as a name - If no such snapshot exists, it is an error Isn't it rather obvious that B is more complex than A? Kevin
signature.asc
Description: PGP signature
