[git pull] vfs.git pile 2: several fixes to backport

[Al Viro <viro@zeniv.linux.org.uk>]

	acct_on() fix for deadlock caught be overlayfs folks,
autofs RCU use-after-free SNAFU (->d_manage() can be called
lockless, so we need to RCU-delay freeing the objects it
looks at) and (hopefully) the end of "do we need freeing this
dentry RCU-delayed" whack-a-mole.

The following changes since commit 79a3aaa7b82e3106be97842dedfd8429248896e6:

  Linux 5.1-rc3 (2019-03-31 14:39:29 -0700)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git stable-fodder

for you to fetch changes up to ce285c267a003acbf607f3540ff71287f82e5282:

  autofs: fix use-after-free in lockless ->d_manage() (2019-04-09 19:18:19 -0400)

----------------------------------------------------------------
Al Viro (3):
      acct_on(): don't mess with freeze protection
      dcache: sort the freeing-without-RCU-delay mess for good.
      autofs: fix use-after-free in lockless ->d_manage()

 Documentation/filesystems/porting |  5 +++++
 fs/autofs/autofs_i.h              |  1 +
 fs/autofs/inode.c                 |  2 +-
 fs/dcache.c                       | 24 +++++++++++++-----------
 fs/internal.h                     |  2 --
 fs/nsfs.c                         |  3 +--
 include/linux/dcache.h            |  2 +-
 include/linux/mount.h             |  2 ++
 kernel/acct.c                     |  4 ++--
 9 files changed, 26 insertions(+), 19 deletions(-)