XFS fixes for 4.19-rc6 Accumlated regression and bug fixes for 4.19-rc6, including: o make iomap correctly mark dirty pages for sub-page block sizes o fix regression in handling extent-to-btree format conversion errors o fix torn log wrap detection for new logs o various corrupt inode detection fixes o various delalloc state fixes o cleanup all the missed transaction cancel cases missed from changes merged in 4.19-rc1 o fix lockdep false positive on transaction allocation o fix locking and reference counting on buffer log items