A missing 'break' statement in bm_status_write() results in a user program
receiving '3' when doing the following:

  write(fd, "-1", 2);
Signed-off-by: NLuis Henriques <luis.henriques@canonical.com>
Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>