commit 8cdf3372 upstream.

If the block size or cluster size is insane, reject the mount.  This
is important for security reasons (although we shouldn't be just
depending on this check).

Ref: http://www.securityfocus.com/archive/1/539661
Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1332506Reported-by: Borislav Petkov <bp@alien8.de>
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>