[libvirt] [PATCH 3/6] qemu: snapshot: Don't redetect backing chain after snapshot

[John Ferlan]

On 12/16/2016 11:24 AM, Peter Krempa wrote:
> Libvirt is able to properly model what happens to the backing chain
> after a snapshot so there's no real need to redetect the data.
> Additionally with the _REUSE_EXT flag this might end up in redetecting
> wrong data if the user puts wrong backing chain reference into the
> snapshot image.
> ---
>  src/qemu/qemu_driver.c | 14 --------------
>  1 file changed, 14 deletions(-)
> 

Fewer callers to the metadata format probing the better!

ACK -

John

> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 30d947b3e..8477ed0dd 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -14324,7 +14324,6 @@ qemuDomainSnapshotCreateDiskActive(virQEMUDriverPtr driver,
>      bool persist = false;
>      bool reuse = (flags & VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT) != 0;
>      virQEMUDriverConfigPtr cfg = NULL;
> -    virErrorPtr orig_err = NULL;
> 
>      if (!virDomainObjIsActive(vm)) {
>          virReportError(VIR_ERR_OPERATION_INVALID,
> @@ -14409,19 +14408,6 @@ qemuDomainSnapshotCreateDiskActive(virQEMUDriverPtr driver,
>          }
>      }
> 
> -    /* recheck backing chains of all disks involved in the snapshot */
> -    orig_err = virSaveLastError();
> -    for (i = 0; i < snap->def->ndisks; i++) {
> -        if (snap->def->disks[i].snapshot != VIR_DOMAIN_SNAPSHOT_LOCATION_EXTERNAL)
> -            continue;
> -        ignore_value(qemuDomainDetermineDiskChain(driver, vm, vm->def->disks[i],
> -                                                  true, true));

Irony is the code asked for reporting broken, but then threw it away -
ok sure it got logged somewhere

> -    }
> -    if (orig_err) {
> -        virSetError(orig_err);
> -        virFreeError(orig_err);
> -    }
> -
>      if (ret == 0 || !virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_TRANSACTION)) {
>          if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm, driver->caps) < 0 ||
>              (persist && virDomainSaveConfig(cfg->configDir, driver->caps,
>