io_channel_set_blksize(channel, SUPERBLOCK_OFFSET);
retval = io_channel_read_blk64(channel, 1, -SUPERBLOCK_SIZE, &super);
if (retval) {
io_channel_set_blksize(channel, SUPERBLOCK_OFFSET);
retval = io_channel_read_blk64(channel, 1, -SUPERBLOCK_SIZE, &super);
if (retval) {