I am going to have to make numerous fields in struct vattr much larger
    to accomodate HAMMER.  I'm fairly sure the changes will not be exposed
    to userland too badly but I can't guarentee it.

    va_nlink, va_fsid, va_fileid, and va_gen will be expanded from 32 to 64
    bits.

    va_uid and va_gid will be expanded from a uid_t/gid_t to a full 
    16-byte uuid_t.  The kernel will convert to and from the standard
    32 bit uid_t and gid_t.

    I will not be changing the ucred structure, that would be a bit too big
    of bite for the moment.

    The statvfs structure will also have to be changed in order to properly
    export the 16 byte fsid.  That will be user-visible, but fortunately
    we have some spare fields we can use for it and I'll name the fields
    f_fsid_uuid and f_owner_uuid and leave the original f_fsid and f_owner
    fields intact.

    We're stuck with the stat structure as-is, changing that would be a huge
    mess.  Fortunately we made the change to 64 bit inodes a long time ago
    (st_ino is the one field we wouldn't be able to fake).

    There may also be an issue with directory cookies, but I don't know
    yet.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>