f2fs-for-5.2-rc1 Another round of various bug fixes came in. Damien improved SMR drive support a bit, and Chao replaced BUG_ON() with reporting errors to user since we've not hit from users but did hit from crafted images. We've found a disk layout bug in large_nat_bits feature which supports very large NAT entries enabled at mkfs. If the feature is enabled, it will give a notice to run fsck to correct the on-disk layout. Enhancement: - reduce memory consumption for SMR drive - better discard handling for multiple partitions - tracepoints for f2fs_file_write_iter/f2fs_filemap_fault - allow to change CP_CHKSUM_OFFSET - detect wrong layout of large_nat_bitmap feature - enhance checking valid data indices Bug fix: - Multiple partition support for SMR drive - deadlock problem in f2fs_balance_fs_bg - add boundary checks to fix abnormal behaviors on fuzzed images - inline_xattr space calculations - replace f2fs_bug_on with errors In addition, this series contains various memory boundary check and sanity check of on-disk consistency.