f2fs-for-5.3-rc1 In this round, we've introduced native swap file support which can exploit DIO, enhanced existing checkpoint=disable feature with additional mount option to tune the triggering condition, and allowed user to preallocate physical blocks in a pinned file which will be useful to avoid f2fs fragmentation in append-only workloads. In addition, we've fixed subtle quota corruption issue. Enhancement: - add swap file support which uses DIO - allocate blocks for pinned file - allow SSR and mount option to enhance checkpoint=disable - enhance IPU IOs - add more sanity checks such as memory boundary access Bug fix: - quota corruption in very corner case of error-injected SPO case - fix root_reserved on remount and some wrong counts - add missing fsck flag Some patches were also introduced to clean up ambiguous i_flags and debugging messages codes.