Summary:
- Add sparse checking & related fixes/cleanups
- Big sparse static checker cleanup
- libxfs: add agfl free deferred op type
- libxfs: transaction commit error checking
- mkfs.xfs discard fixes
- mkfs.xfs: discard only after all validations
- xfs_repair: fix segfault in longform_dir2_entry_check
- xfs_repair: fix ASSERT in xfs_bunmapi
- xfs_repair: fix readahead thread deadlock/stall
- xfs_repair: avoid writing back all inodes
- xfs_repair: don't treat directory root LEAFN as corrupt
- xfs_io: add crc32 self test
- xfs_io readv/writev cleanup
- xfs_io: remove useless do_preadv and do_pwritev arguments
- xfs_scrub: lack of kernel support is not a service failure
- xfs_scrub_all: fix systemd escaping
- Majority of 4.19 libxfs changes merged from kernel
- Remove retpoline support