expandable RAID-Z

*** 178,188 ****
--- 178,210 ----
          }
  
          sm->sm_space -= size;
  }
  
+ 
+ 
  int
+ space_map_fold(space_map_t *sm, uint8_t oldwidth, uint8_t newwidth)
+ {
+         space_seg_t *ss;
+         uint64_t d, r;
+ 
+         ASSERT(MUTEX_HELD(sm->sm_lock));
+ 
+         for (ss = avl_first(&sm->sm_root); ss != NULL;
+             ss = AVL_NEXT(&sm->sm_root, ss)) {
+                 d = ss->ss_start / oldwidth;
+                 r = ss->ss_start % oldwidth;
+                 ss->ss_start = d * newwidth + r;
+ 
+                 d = ss->ss_end / oldwidth;
+                 r = ss->ss_end % oldwidth;
+                 ss->ss_end = d * newwidth + r;
+         }
+ }
+ 
+ int
  space_map_contains(space_map_t *sm, uint64_t start, uint64_t size)
  {
          avl_index_t where;
          space_seg_t ssearch, *ss;
          uint64_t end = start + size;
*** 343,355 ****
  
                  entry_map_end = entry_map + (size / sizeof (uint64_t));
                  for (entry = entry_map; entry < entry_map_end; entry++) {
                          uint64_t e = *entry;
  
!                         if (SM_DEBUG_DECODE(e))         /* Skip debug entries */
                                  continue;
  
                          (SM_TYPE_DECODE(e) == maptype ?
                              space_map_add : space_map_remove)(sm,
                              (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart,
                              SM_RUN_DECODE(e) << sm->sm_shift);
                  }
--- 365,386 ----
  
                  entry_map_end = entry_map + (size / sizeof (uint64_t));
                  for (entry = entry_map; entry < entry_map_end; entry++) {
                          uint64_t e = *entry;
  
!                         if (SM_IS_DEBUG(e))             /* Skip debug entries */
                                  continue;
  
+                         if (SM_IS_SPECIAL(e)) {
+                                 uint8_t oldwidth, newwidth;
+                                 ASSERT(SM_SPECIAL_ACTION_DECODE(e) == SM_FOLD);
+                                 oldwidth = BF64_ENCODE(e, 0, 8);
+                                 newwidth = BF64_ENCODE(e, 8, 8);
+                                 space_map_fold(sm, oldwidth, newwidth);
+                                 continue;
+                         }
+ 
                          (SM_TYPE_DECODE(e) == maptype ?
                              space_map_add : space_map_remove)(sm,
                              (SM_OFFSET_DECODE(e) << sm->sm_shift) + mapstart,
                              SM_RUN_DECODE(e) << sm->sm_shift);
                  }