Re: [Qemu-devel] RFC: Make 'info snapshots' show all of snapshots with multiple devices info

[Kevin Wolf <kwolf@redhat.com>]

Am 22.05.2016 um 11:55 hat Lin Ma geschrieben:
> Currently, the output of 'info snapshots' show fully available snapshots.
>  
> In my opinion there are 2 disadvantages:
> 1. It's opaque, hides some snapshot information to users. It's not convenient
> if users want to know more about all of snapshots on every block device via
> monitor.
>  
> 2. It uses snapshot id to determine whether the snapshots are 'fully
> available'.
> It causes incorrect output in some scenario.
>  
> For instance:
> (qemu) info block
> drive_image1 (#block113): /opt/vms/SLES12-SP1-JeOS-x86_64-GM/disk0.qcow2
> (qcow2)
>     Cache mode:       writeback
>  
> drive_image2 (#block349): /opt/vms/SLES12-SP1-JeOS-x86_64-GM/disk1.qcow2
> (qcow2)
>     Cache mode:       writeback
> (qemu)
> (qemu) info snapshots
> There is no snapshot available.
> (qemu)
> (qemu) snapshot_blkdev_internal drive_image1 snap1
> (qemu)
> (qemu) info snapshots
> There is no suitable snapshot available
> (qemu)
> (qemu) savevm checkpoint-1
> (qemu)
> (qemu) info snapshots
> ID        TAG                 VM SIZE                DATE       VM CLOCK
> 1         snap1                     0 2016-05-22 16:57:31   00:01:30.567
> (qemu)
> 
> $ qemu-img snapshot -l disk0.qcow2
> Snapshot list:
> ID        TAG                 VM SIZE                DATE       VM CLOCK
> 1         snap1                     0 2016-05-22 16:57:31   00:01:30.567
> 2         checkpoint-1           165M 2016-05-22 16:58:07   00:02:06.813
> 
> $ qemu-img snapshot -l disk1.qcow2
> Snapshot list:
> ID        TAG                 VM SIZE                DATE       VM CLOCK
> 1         checkpoint-1              0 2016-05-22 16:58:07   00:02:06.813
>  
>  
>  
> I'd like to patch it to make the output looking like this:
> (qemu) info snapshots
>  
> Snapshot list from drive_image1:
> ID        TAG                 VM SIZE                DATE       VM CLOCK
> 1         snap1                     0 2016-05-22 16:57:31   00:01:30.567
> 2         checkpoint-1           165M 2016-05-22 16:58:07   00:02:06.813
>  
> 
> Snapshot list from  drive_image2:
> ID        TAG                 VM SIZE                DATE       VM CLOCK
> 1         checkpoint-1              0 2016-05-22 16:58:07   00:02:06.813

I think that would clutter the output too much in the common case where
all images have the same snapshots. How about having a list with all
loadable snapshots first, and then only an additional list for images
that have snapshots that aren't present on all images?

(qemu) info snapshots
List of snapshots present on all disks:
 ID        TAG                 VM SIZE                DATE       VM CLOCK
 --        checkpoint-1           165M 2016-05-22 16:58:07   00:02:06.813

List of partial (non-loadable) snapshots on 'drive_image1':
 ID        TAG                 VM SIZE                DATE       VM CLOCK
 1         snap1                     0 2016-05-22 16:57:31   00:01:30.567

Kevin