ftl: separate code to start a transaction

source/ftl/ftl.c

@@ -44,40 +44,51 @@ size_t ftl_read(struct ftl_map *map, void *data, size_t len, uint32_t va)
 		len);
 }
 
-static int ftl_seek(struct ftl_map *map, uint32_t va)
+static int ftl_start_transaction(struct ftl_map *map, uint32_t va)
 {
-	size_t len;
+	uint32_t page;
 	int ret;
-	uint32_t offset, page, dst, src;
 
-	if (va >= ftl_get_capacity(map))
+	if ((map->outstanding.flags & FTL_PRESENT) && map->outstanding.va == va)
+		return 0;
+
+	if (ftl_sync(map) < 0)
 		return -1;
 
-	offset = va & ((1 << map->log2_page_size) - 1);
-	va >>= map->log2_page_size;
+	if ((ret = trace_path(map, NULL, &page, va)) < 0 && ret != -ERR_NOT_FOUND)
+		return -1;
+
+	if (prepare_head(map) < 0)
+		return -1;
+
+	map->outstanding.flags |= FTL_PRESENT;
+	map->outstanding.va = va;
+	map->outstanding.page = page;
+
+	if (ret == -ERR_NOT_FOUND) {
+		map->outstanding.flags |= FTL_NO_MAPPING;
+		++map->nused_pages;
+	}
 
-	if (!(map->outstanding.flags & FTL_PRESENT) || map->outstanding.va != va) {
-		if (ftl_sync(map) < 0)
-			return -1;
+	map->offset = 0;
 
-		if ((ret = trace_path(map, NULL, &page, va)) < 0 &&
-			ret != -ERR_NOT_FOUND)
-			return -1;
+	return 0;
+}
 
-		if (prepare_head(map) < 0)
-			return -1;
+static int ftl_seek(struct ftl_map *map, uint32_t va)
+{
+	size_t len;
+	uint32_t offset, dst, src;
+	int ret;
 
-		map->outstanding.flags |= FTL_PRESENT;
-		map->outstanding.va = va;
-		map->outstanding.page = page;
+	if (va >= ftl_get_capacity(map))
+		return -1;
 
-		if (ret == -ERR_NOT_FOUND) {
-			map->outstanding.flags |= FTL_NO_MAPPING;
-			++map->nused_pages;
-		}
+	offset = va & ((1 << map->log2_page_size) - 1);
+	va >>= map->log2_page_size;
 
-		map->offset = 0;
-	}
+	if (ftl_start_transaction(map, va) < 0)
+		return -1;
 
 	if (offset < map->offset)
 		return -1;