block: Add support to warn on backing file change without format

For now, this is a mechanical addition; all callers pass false. But
the next patch will use it to improve 'qemu-img rebase -u' when
selecting a backing file with no format.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Message-Id: <20200706203954.341758-10-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Eric Blake 2020-07-06 15:39:53 -05:00 committed by Kevin Wolf
parent b66ff2c298
commit e54ee1b385
6 changed files with 18 additions and 10 deletions

View file

@ -78,7 +78,7 @@ static int stream_prepare(Job *job)
}
}
bdrv_set_backing_hd(bs, base, &local_err);
ret = bdrv_change_backing_file(bs, base_id, base_fmt);
ret = bdrv_change_backing_file(bs, base_id, base_fmt, false);
if (local_err) {
error_report_err(local_err);
return -EPERM;