xfs: update for 3.6-rc1 Numerous cleanups and several bug fixes. Here are some highlights: * Discontiguous directory buffer support * Inode allocator refactoring * Removal of the IO lock in inode reclaim * Implementation of .update_time * Fix for handling of EOF in xfs_vm_writepage * Fix for races in xfsaild, and idle mode is re-enabled * Fix for a crash in xfs_buf completion handlers on unmount.