ocfs2: fix race between crashed dio and rm

ocfs2: fix race between crashed dio and rm

There is a race case between crashed dio and rm, which will lead to
OCFS2_VALID_FL not set read-only.

  N1                              N2
  ------------------------------------------------------------------------
  dd with direct flag
                                  rm file
  crashed with an dio entry left
  in orphan dir
                                  clear OCFS2_VALID_FL in
                                  ocfs2_remove_inode
                                  recover N1 and read the corrupted inode,
                                  and set filesystem read-only

So we skip the inode deletion this time and wait for dio entry recovered
first.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>