Darren J Moffat wrote: > I've been hoping to use elements of the blkptr_t as the initalisation > vector (IV) for the AES crypto algorithms - specifically the offset and > blk_birth. When do these get filled in ?
This happens during the allocate phase of the pipeline (either zio_dva_allocate or zio_write_allocate_gang_members). The value will be set to whatever zio->io_txg holds. > > I was expecting them to be filled in by the time we reached the > ZIO_WRITE_ENCRYPT_STAGE (after compression but before checksum), but it > appears that only blk_props is filled in at this point. > > So maybe I should be looking at io_txg instead. Should work. > > I need an IV that is guaranteed unique over the life time of the pool > that is also unique per encryption key (which for phase 1 of zfs-crypto > means unique per dataset). Since there could be multiple blocks being > encrypted for the same dataset in a given transaction group (highly > likely in fact) the txg alone is not enough. >
