nilfs2-kmod7 1.2.9

• Backport recent fixes for various issues reported by syzbot:
  • fix use-after-free bug of nilfs_root in nilfs_evict_inode()
  • reject devices with insufficient block count
  • fix possible out-of-bounds segment allocation in resize ioctl
  • fix incomplete buffer cleanup in nilfs_btnode_abort_change_key()
• Add some new macro and inline function compatibility definitions for maintenance:
  • Allow to use U64_MAX and similar definitions
  • Allow to use bdev_nr_bytes() and sb_bdev_nr_blocks()