--- old/usr/src/uts/common/fs/zfs/sys/space_map.h	Mon Apr  7 00:45:26 2008
+++ new/usr/src/uts/common/fs/zfs/sys/space_map.h	Mon Apr  7 00:45:26 2008
@@ -73,23 +73,29 @@
 };
 
 /*
- * debug entry
+ * allocation/free entry
  *
- *    1      3         10                     50
- *  ,---+--------+------------+---------------------------------.
- *  | 1 | action |  syncpass  |        txg (lower bits)         |
- *  `---+--------+------------+---------------------------------'
- *   63  62    60 59        50 49                               0
- *
- *
- *
- * non-debug entry
- *
  *    1               47                   1           15
- *  ,-----------------------------------------------------------.
+ *  ,---+------------------------------+------+-----------------.
  *  | 0 |   offset (sm_shift units)    | type |       run       |
- *  `-----------------------------------------------------------'
+ *  `---+------------------------------+------+-----------------'
  *   63  62                          17   16   15               0
+ *
+ * special entry
+ *
+ *    1   1      6                        56
+ *  ,---+---+----------+----------------------------------------.
+ *  | 1 | 1 |  action  |           <action specific>            |
+ *  `---+---+----------+----------------------------------------'
+ *   63  62  61      56 55                                      0
+ *   
+ * debug entry
+ *
+ *    1   1     2         10                     50
+ *  ,---+---+--------+----------+-------------------------------.
+ *  | 1 | 0 | action | syncpass |       txg (lower bits)        |
+ *  `---+---+--------+----------+-------------------------------'
+ *   63  62  61    60 59      50 49                             0
  */
 
 /* All this stuff takes and returns bytes */
@@ -99,15 +105,19 @@
 #define	SM_TYPE_ENCODE(x)	BF64_ENCODE(x, 15, 1)
 #define	SM_OFFSET_DECODE(x)	BF64_DECODE(x, 16, 47)
 #define	SM_OFFSET_ENCODE(x)	BF64_ENCODE(x, 16, 47)
-#define	SM_DEBUG_DECODE(x)	BF64_DECODE(x, 63, 1)
-#define	SM_DEBUG_ENCODE(x)	BF64_ENCODE(x, 63, 1)
 
+#define	SM_IS_SPECIAL(x)	(BF64_DECODE(x, 62, 2) == 3)
+#define	SM_SPECIAL_ENCODE()	BF64_ENCODE(3, 62, 2)
+#define	SM_IS_DEBUG(x)		(BF64_DECODE(x, 62, 2) == 2)
+#define	SM_DEBUG_ENCODE()	BF64_ENCODE(2, 62, 2)
+
+#define	SM_SPECIAL_ACTION_DECODE(x)	BF64_DECODE(x, 56, 6)
+#define	SM_SPECIAL_ACTION_ENCODE(x)	BF64_ENCODE(x, 56, 6)
+
 #define	SM_DEBUG_ACTION_DECODE(x)	BF64_DECODE(x, 60, 3)
 #define	SM_DEBUG_ACTION_ENCODE(x)	BF64_ENCODE(x, 60, 3)
-
 #define	SM_DEBUG_SYNCPASS_DECODE(x)	BF64_DECODE(x, 50, 10)
 #define	SM_DEBUG_SYNCPASS_ENCODE(x)	BF64_ENCODE(x, 50, 10)
-
 #define	SM_DEBUG_TXG_DECODE(x)		BF64_DECODE(x, 0, 50)
 #define	SM_DEBUG_TXG_ENCODE(x)		BF64_ENCODE(x, 0, 50)
 
@@ -116,6 +126,8 @@
 #define	SM_ALLOC	0x0
 #define	SM_FREE		0x1
 
+#define	SM_FOLD		0x01
+
 /*
  * The data for a given space map can be kept on blocks of any size.
  * Larger blocks entail fewer i/o operations, but they also cause the