[pve-devel] applied: [PATCH stable-7 qemu] fix #2258: select correct device when removing drive snapshot via QEMU

[Thomas Lamprecht]

On 21/03/2024 13:29, Maximiliano Sandoval wrote:
> The QMP command needs to be issued for the device where the disk is
> currently attached, not for the device where the disk was attached at
> the time the snapshot was taken.
> 
> Fixes the following scenario with a disk image for which
> do_snapshots_with_qemu() is true (i.e. qcow2 or RBD+krbd=0):
> 1. Take snapshot while disk image is attached to a given bus+ID.
> 2. Detach disk image.
> 3. Attach disk image to a different bus+ID.
> 4. Remove snapshot.
> 
> Previously, this would result in an error like:
>> blockdev-snapshot-delete-internal-sync' failed - Cannot find device=drive-scsi1 nor node_name=drive-scsi1
> 
> While the $running parameter for volume_snapshot_delete() is planned
> to be removed on the next storage plugin APIAGE reset, it currently
> causes an immediate return in Storage/Plugin.pm. So passing a truthy
> value would prevent removing a snapshot from an unused qcow2 disk that
> was still used at the time the snapshot was taken. Thus, and because
> some exotic third party plugin might be using it for whatever reason,
> it's necessary to keep passing the same value as before.
> 
> Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
> Signed-off-by: Maximiliano Sandoval <m.sandoval at proxmox.com>
> ---
> 
> This is a backport for Proxmox VE 7 of
> https://lists.proxmox.com/pipermail/pve-devel/2022-September/054124.html which
> was applied at
> https://git.proxmox.com/?p=qemu-server.git;a=commit;h=c60586838a4bfbd4f879c509195cbfb1291db443.
> 

If you use `git cherry-pick -xs COMMIT` the -x will add a reference
that this was cherry-picked from a commit and the -s adds your S-o-b,
which makes it a bit nicer as one can immediately see where it comes
from when checking the git log.

I amended that info in this time.

> I tested this by creating a new Proxmox VE 7.4 VM, creating a new VM inside with
> storage as IDE, taking a snapshot while the VM is running, detach the storage
> and add it back as SCSI, then deleting the snapshot.
> 
>  PVE/QemuServer.pm | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)


applied, thanks!