This likely fixes the oops in __lock_acquire reported as:

http://www.kerneloops.org/raw.php?rawid=2753&msgid=
http://www.kerneloops.org/raw.php?rawid=2749&msgid=

In these reported oopses, start_this_handle is returning -EROFS.
Signed-off-by: NJonas Bonn <jonas.bonn@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>