On 8/19/19 1:55 PM, Max Reitz wrote: > qcow2 v3 requires every snapshot table entry to have two extra data > fields: The 64-bit VM state size, and the virtual disk size. Both are > optional for v2 images, so they may not be present. > > qcow2_upgrade() therefore should update the snapshot table to ensure all > entries have these extra data fields. > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1727347 > Reported-by: Eric Blake <ebl...@redhat.com> > Signed-off-by: Max Reitz <mre...@redhat.com> > --- > block/qcow2.c | 32 ++++++++++++++++++++++++++++++-- > 1 file changed, 30 insertions(+), 2 deletions(-) >
> @@ -4768,7 +4770,33 @@ static int qcow2_upgrade(BlockDriverState *bs, int
> target_version,
> /* There are no other versions (yet) that you can upgrade to */
> assert(target_version == 3);
>
> - status_cb(bs, 0, 1, cb_opaque);
> + status_cb(bs, 0, 2, cb_opaque);
> +
> + /*
> + * In v2, snapshots do not need to have extra data. v3 requires
> + * the 64-bit VM state size and the virtual disk size to be
> + * present.
> + * qcow2_write_snapshots() will always write the list in the
> + * v3-compliant format.
> + */
> + need_snapshot_update = false;
> + for (i = 0; i < s->nb_snapshots; i++) {
> + if (s->snapshots[i].extra_data_size <
> + sizeof_field(QCowSnapshotExtraData, vm_state_size_large) +
> + sizeof_field(QCowSnapshotExtraData, disk_size))
sizeof(extra) would be more concise than two sizeof_field() added
together, but might cause problems if we later expand the size of extra
for other reasons, but don't revisit this code. So I actually like what
you did here.
Reviewed-by: Eric Blake <ebl...@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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