commit 29333920 upstream.

A couple of fields in affs_sb_info is used in follow_link() and
symlink() for handling AFFS "absolute" symlinks.  Need locking
against affs_remount() updates.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>