sizeof(struct g_eli_metadata) will return the exact number of bytes needed for storing it on the disk. Without this change GELI was unusable on amd64 (and probably other 64-bit archs), because sizeof(struct g_eli_metadata) was greater than 512 bytes and geli(8) was failing on assertion. Reported by: Michael Reifenberger <mike@Reifenberger.com> MFC after: 3 days