commit bc5b8a90 upstream.

On a corrupted file system the ->len field could be wrong leading to
a buffer overflow.
Reported-and-acked-by: Clement LECIGNE <clement.lecigne@netasq.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>