K 10
svn:author
V 3
mjg
K 8
svn:date
V 27
2014-10-20T18:00:50.782581Z
K 7
svn:log
V 299
Provide vfs suspension support only for filesystems which need it, take
two.

nullfs and unionfs need to request suspension if underlying filesystem(s)
use it. Utilize mnt_kern_flag for this purpose.

This is a fixup for 273271.

No strong objections from: kib
Pointy hat to: mjg
MFC after:	2 weeks

END