ocd_blocksize should actually be called ocd_blockbits. Similarly, ocd_inodespace should be called ocd_inodebits, and fed_pagesize should be called fed_pagebits, and ddp_inodespace called ddp_inodebits, since they are all log2 of the actual device size.
This further exposes another bug in the OFD code, that ddp_inodespace is used as a "size" in ofd_recovery_complete(), ofd_grant_chunk(), and ofd_grant_create(), instead of a log2 shift when computing the reserved space for inode precreation. Same in both the ldiskfs and ZFS osd_conf_get() implementations.