Re: [PATCH v3 06/10] qemu snapshot: use QMP snapshot-save for internal snapshots creation

On 10/3/24 15:46, Peter Krempa wrote: > From: Nikolai Barybin via Devel <devel(a)lists.libvirt.org&gt; > > The usage of HMP commands are highly discouraged by qemu. Moreover, > current snapshot creation routine does not provide flexibility in > choosing target device for VM state snapshot. > > This patch makes use of QMP commands snapshot-save and by > default chooses first writable non-shared qcow2 disk (if present) > as target for VM state. > > Signed-off-by: Nikolai Barybin <nikolai.barybin(a)virtuozzo.com&gt; > Signed-off-by: Peter Krempa <pkrempa(a)redhat.com&gt; > --- > src/qemu/qemu_snapshot.c | 124 ++++++++++++++++++++++++++++++++++++--- > 1 file changed, 116 insertions(+), 8 deletions(-) > > diff --git a/src/qemu/qemu_snapshot.c b/src/qemu/qemu_snapshot.c > index f5260c4a22..d4602d386f 100644 > --- a/src/qemu/qemu_snapshot.c > +++ b/src/qemu/qemu_snapshot.c > @@ -309,6 +309,99 @@ qemuSnapshotCreateInactiveExternal(virQEMUDriver *driver, > } > > > +static char ** > +qemuSnapshotActiveInternalCreateGetDevices(virDomainObj *vm, > + virDomainSnapshotDef *snapdef) > +{ > + g_auto(GStrv) devices = g_new0(char *, vm->def->ndisks + 2); > + size_t ndevs = 0; > + size_t i = 0; > + > + /* This relies on @snapdef being aligned and validated via > + * virDomainSnapshotAlignDisks() and qemuSnapshotPrepare(), which also > + * ensures that all disks are backed by qcow2. */ > + for (i = 0; i < snapdef->ndisks; i++) { > + virDomainSnapshotDiskDef *snapdisk = snapdef->disks + i; > + virDomainDiskDef *domdisk = vm->def->disks[i]; > + Could you clarify why to use 2 different types of addressing in 2 consecutive lines of code? ( '+i' and [i])