K 10
svn:author
V 5
markj
K 8
svn:date
V 27
2019-08-27T14:06:34.562833Z
K 7
svn:log
V 521
Fix several logic issues in domainset_empty_vm().

- Don't add 1 to the result of DOMAINSET_FLS.
- Do not modify domainsets containing only empty domains.
- Always flatten a _PREFER policy to _ROUNDROBIN if the preferred
  domain is empty.  Previously we were doing this only when ds_cnt > 1.

These bugs could cause hangs during boot if a VM domain is empty.

Tested by:	hselasky
Reviewed by:	hselasky, kib
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21420

END