vm_fault_hold: handle vm_page_rename failure

On vm_page_rename failure, fix a missing object unlock and a double free of
a page.

First remove the old page, then rename into other page into first_object,
then free the old page.  This avoids the problem on rename failure.  This is
a little ugly but seems to be the most straightforward solution.

Tested with:
  $ sysctl debug.fail_point.uma_zalloc_arg="1%return"
  $ kyua test -k /usr/tests/sys/Kyuafile

Submitted by:	Ryan Libby <rlibby@gmail.com>
Reviewed by:	kib
Seen by:	alc
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D4326

0 files changed, 0 insertions, 0 deletions