Hi all, with all the PI and checksumming discussions I decided to dust of my old XFS PI and data checksumming prototypes. This is pre-alpha code so handle it with care. I tried to document most issues and limitations in the patch, but I might have missed some. It survives an xfstests quick run with just three failures, one of which is a pre-existing failure on a PI disable device when creating dm-thin. As it depends on various other in-flight patch series anyone daring to it should use the git branch here: git://git.infradead.org/users/hch/misc.git xfs-data-crc instead.