Applied innodb-5.0-ss660 snapshot.

innobase/btr/btr0cur.c:
  Applied innodb-5.0-ss660 snapshot.
   btr_cur_search_to_nth_level(): Reacquire btr_search_latch after
   inserting to the insert buffer. This was noticed while analyzing
   Bug#19081 but this shold not fix this bug since according to
   Heikki, btr_search_latch is not reserved during an insert.
innobase/ibuf/ibuf0ibuf.c:
  Applied innodb-5.0-ss660 snapshot.
   ibuf_fixed_addr_page(): Add parameter space. As the insert buffer
   B-tree is only located in the system tablespace (space 0),
   IBUF_TREE_ROOT_PAGE_NO is only special in space 0.
innobase/include/sync0rw.ic:
  Applied innodb-5.0-ss660 snapshot.
   rw_lock_s_unlock_func(): Change a debug assertion to a
   production assertion in order to track down Bug#19081.

innobase/btr/btr0cur.c

@@ -439,7 +439,7 @@ btr_cur_search_to_nth_level(
 				if (UNIV_LIKELY_NULL(heap)) {
 					mem_heap_free(heap);
 				}
-				return;
+				goto func_exit;
 			}
 
 			/* Insert to the insert buffer did not succeed:
@@ -555,6 +555,7 @@ btr_cur_search_to_nth_level(
 						|| mode != PAGE_CUR_LE);
 	}
 
+func_exit:
 	if (has_search_latch) {
 		
 		rw_lock_s_lock(&btr_search_latch);

innobase/ibuf/ibuf0ibuf.c

@@ -950,14 +950,11 @@ ibool
 ibuf_fixed_addr_page(
 /*=================*/
 			/* out: TRUE if a fixed address ibuf i/o page */
+	ulint	space,	/* in: space id */
 	ulint	page_no)/* in: page number */
 {
-	if ((ibuf_bitmap_page(page_no))
-				|| (page_no == IBUF_TREE_ROOT_PAGE_NO)) {
-		return(TRUE);
-	}
-
-	return(FALSE);
+	return((space == 0 && page_no == IBUF_TREE_ROOT_PAGE_NO)
+			|| ibuf_bitmap_page(page_no));
 }
 
 /***************************************************************************
@@ -981,7 +978,7 @@ ibuf_page(
 		return(FALSE);
 	}
 
-	if (ibuf_fixed_addr_page(page_no)) {
+	if (ibuf_fixed_addr_page(space, page_no)) {
 
 		return(TRUE);
 	}
@@ -1029,7 +1026,7 @@ ibuf_page_low(
 		return(FALSE);
 	}
 #endif	
-	if (ibuf_fixed_addr_page(page_no)) {
+	if (ibuf_fixed_addr_page(space, page_no)) {
 
 		return(TRUE);
 	}
@@ -3052,7 +3049,7 @@ ibuf_merge_or_delete_for_page(
 		return;
 	}
 #endif	
-	if (ibuf_fixed_addr_page(page_no) || fsp_descr_page(page_no)
+	if (ibuf_fixed_addr_page(space, page_no) || fsp_descr_page(page_no)
 					|| trx_sys_hdr_page(space, page_no)) {
 		return;
 	}

innobase/include/sync0rw.ic

@@ -362,7 +362,7 @@ rw_lock_s_unlock_func(
 
 	/* Reset the shared lock by decrementing the reader count */
 
-	ut_ad(lock->reader_count > 0);
+	ut_a(lock->reader_count > 0);
 	lock->reader_count--;
 
 #ifdef UNIV_SYNC_DEBUG