Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs fixes from Al Viro:
 "These four commits are obvious fixes (a couple of fdget_pos()-related
  ones from Eric Biggers, prepend_name() fix, missing checks for false
  negatives from __lookup_mnt() in fs/namei.c)"

For now I'm pulling just the four obvious fixes, there's another four
pending in Al's 'for-linus' branch wrt the mnt_hash list that were more
involved.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  rcuwalk: recheck mount_lock after mountpoint crossing attempts
  make prepend_name() work correctly when called with negative *buflen
  vfs: Don't let __fdget_pos() get FMODE_PATH files
  vfs: atomic f_pos access in llseek()