vfs: stop refing freed mount points in vop_stdgetwritemount

The code used blindly ref based on an unsafely red address and then would
backpedal if necessary. This was safe in terms of memory access since
mounts are type-stable, but made for a potential a bug where the mount
was reused and had the count reset to 0 before this code decreased it.

Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21411

0 files changed, 0 insertions, 0 deletions