On 25.06.2020 18:21, Max Reitz wrote:
This allows us to differentiate between filters and nodes with COW
backing files: Filters cannot be used as overlays at all (for this
function).
Signed-off-by: Max Reitz <mre...@redhat.com>
---
blockdev.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/blockdev.c b/blockdev.c
index 1eb0fcdea2..aabe51036d 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1549,7 +1549,12 @@ static void external_snapshot_prepare(BlkActionState
*common,
goto out;
}
- if (state->new_bs->backing != NULL) {
+ if (state->new_bs->drv->is_filter) {
Is there a chance to get a filter here? If so, is that when a user
specifies the file name of such a kind “filter[filter-name]:foo.qcow2”
or somehow else?
Andrey
+ error_setg(errp, "Filters cannot be used as overlays");
+ goto out;
+ }
+
+ if (bdrv_cow_child(state->new_bs)) {
error_setg(errp, "The overlay already has a backing image");
goto out;
}
Reviewed-by: Andrey Shinkevich <andrey.shinkev...@virtuozzo.com>
