xfs, iomap: update for 4.8-rc3 Changes in this update - regression fixes for XFS changes introduce in 4.8-rc1 - buffer IO accounting assert failure - ENOSPC block accounting reservation issue - DAX IO path page cache invalidation fix - rmapbt on-disk block count in agf - correct classification of rmap block type when updating AGFL. - iomap support for attribute fork mapping - regression fixes for iomap infrastructure in 4.8-rc1 - fiemap: honor FIEMAP_FLAG_SYNC - fiemap: implement FIEMAP_FLAG_XATTR support to fix XFS regression - make mark_page_accessed and pagefault_disable usage consistent with other IO paths