patch lower-case-segops

*** 138,148 ****
          }
  
          vp_end = vp_off + vp_len;
          ASSERT(off >= vp_off && off < vp_end);
  
!         if (isra && SEGOP_KLUSTER(seg, addr, 0))
                  return ((page_t *)NULL);        /* segment driver says no */
  
          if ((plist = page_create_va(vp, off,
              PAGESIZE, PG_EXCL | PG_WAIT, seg, addr)) == NULL)
                  return ((page_t *)NULL);
--- 138,148 ----
          }
  
          vp_end = vp_off + vp_len;
          ASSERT(off >= vp_off && off < vp_end);
  
!         if (isra && segop_kluster(seg, addr, 0))
                  return ((page_t *)NULL);        /* segment driver says no */
  
          if ((plist = page_create_va(vp, off,
              PAGESIZE, PG_EXCL | PG_WAIT, seg, addr)) == NULL)
                  return ((page_t *)NULL);
*** 160,170 ****
                      deltab += PAGESIZE) {
                          /*
                           * Call back to the segment driver to verify that
                           * the klustering/read ahead operation makes sense.
                           */
!                         if (SEGOP_KLUSTER(seg, addr, -deltab))
                                  break;          /* page not eligible */
                          if ((pp = page_create_va(vp, off - deltab,
                              PAGESIZE, PG_EXCL, seg, addr - deltab))
                              == NULL)
                                  break;          /* already have the page */
--- 160,170 ----
                      deltab += PAGESIZE) {
                          /*
                           * Call back to the segment driver to verify that
                           * the klustering/read ahead operation makes sense.
                           */
!                         if (segop_kluster(seg, addr, -deltab))
                                  break;          /* page not eligible */
                          if ((pp = page_create_va(vp, off - deltab,
                              PAGESIZE, PG_EXCL, seg, addr - deltab))
                              == NULL)
                                  break;          /* already have the page */
*** 180,190 ****
                      deltaf += PAGESIZE) {
                          /*
                           * Call back to the segment driver to verify that
                           * the klustering/read ahead operation makes sense.
                           */
!                         if (SEGOP_KLUSTER(seg, addr, deltaf))
                                  break;          /* page not file extension */
                          if ((pp = page_create_va(vp, off + deltaf,
                              PAGESIZE, PG_EXCL, seg, addr + deltaf))
                              == NULL)
                                  break;          /* already have page */
--- 180,190 ----
                      deltaf += PAGESIZE) {
                          /*
                           * Call back to the segment driver to verify that
                           * the klustering/read ahead operation makes sense.
                           */
!                         if (segop_kluster(seg, addr, deltaf))
                                  break;          /* page not file extension */
                          if ((pp = page_create_va(vp, off + deltaf,
                              PAGESIZE, PG_EXCL, seg, addr + deltaf))
                              == NULL)
                                  break;          /* already have page */