fellow_cache: Use new fdo pointer (but no change yet)

src/fellow_cache.c

@@ -345,7 +345,6 @@ static inline uint16_t							\
 
 SEGLIST_FIT_FUNC(disk)
 
-//struct fellow_disk_obj;
 struct fellow_cache_obj;
 struct fellow_cache_seg {
 	uint16_t			magic;
@@ -1087,10 +1086,12 @@ fellow_busy_io_submit(struct fellow_busy_io *fbio)
 static inline struct fellow_disk_obj *
 fellow_disk_obj(const struct fellow_cache_seg *fcs)
 {
-	AN(fcs);
-	AN(fcs->alloc.ptr);
+
+	CHECK_OBJ_NOTNULL(fcs, FELLOW_CACHE_SEG_MAGIC);
 	assert(FCOS_HIGH(fcs->state) == FCO_HIGH);
-	return (fcs->alloc.ptr);
+	if (fcs->alloc.ptr != NULL)
+		assert(fcs->alloc.ptr == fcs->u.fco_fdo);
+	return (fcs->u.fco_fdo);
 }
 
 static const char *
@@ -1180,16 +1181,18 @@ fellow_disk_obj_trim(const struct fellow_cache *fc,
 			mem = buddy_alloc1_ptr_extent_wait(fc->membuddy,
 			    FEP_SPCPRI, trim_sz, 0);
 			if (mem.ptr) {
-				memcpy(mem.ptr, fcs->alloc.ptr, trim_sz);
+				memcpy(mem.ptr, fdo, trim_sz);
 				buddy_return1_ptr_extent(fc->membuddy,
 				    &fcs->alloc);
 				fcs->alloc = mem;
+				fcs->u.fco_fdo = mem.ptr;
 				break;
 			}
 		}
 		/* FALLTHROUGH */
 	case FCO_WRITING:
 		buddy_trim1_ptr_extent(fc->membuddy, &fcs->alloc, trim_sz);
+		assert(fdo == fcs->alloc.ptr);
 		break;
 	default:
 		WRONG("fcs->state to call fellow_disk_obj_trim()");
@@ -1403,8 +1406,11 @@ assert_cache_seg_consistency(const struct fellow_cache_seg *fcs)
 		AN(fcs->alloc.size);			\
 	} while(0)
 #define FCOA_MEM do {						\
-		AN(fcs->alloc.ptr);			\
+	    /* can be NULL for embedded fdo */			\
+	    if (fcs->alloc.ptr != NULL) {			\
 		AN(fcs->alloc.size);				\
+		assert(fcs->alloc.ptr == fcs->u.fco_fdo);	\
+	    }							\
 	} while(0)
 #define FDSA_NULL AZ(fcs->disk_seg)
 #define FDSA_MAY CHECK_OBJ_ORNULL(fcs->disk_seg, FELLOW_DISK_SEG_MAGIC)
@@ -2156,6 +2162,7 @@ fellow_cache_obj_new(
 	fellow_cache_seg_init(fcs, fco, FCO_INIT);
 
 	fcs->alloc = fdo_mem;
+	fcs->u.fco_fdo = fdo;
 
 	return (FCR_OK(fco));
   err: