if (rc || (xlen == 0))
if (rc || (xaddr == 0))
static struct metapage *read_index_page(struct inode *inode, s64 blkno){	int rc;	s64 xaddr;	int xflag;	s32 xlen;	rc = xtLookup(inode, blkno, 1, &xflag, &xaddr, &xlen, 1);	if (rc || (xlen == 0))		return NULL;	return read_metapage(inode, xaddr, PSIZE, 1);}