fil0fil.c:

  We accidentally checked if the DIRECTORY is of type OS_FILE_TYPE_UNKNOWN; our intention was to check if the FILE is that; best to remove the check altogether, as in crash recovery it is safest to try to open also files whose type is unknown
os0file.c:
  Fix a bug: in Windows, os_file_readdir_next_file() returned OS_FILE_TYPE_UNKNOWN as the type of a regular file; this did not break mysqld, but did break ibbackup on Windows

innobase/fil/fil0fil.c

@@ -3002,8 +3002,8 @@ fil_load_single_table_tablespaces(void)
 				/* printf(
 "     Looking at file %s\n", fileinfo.name); */
 
-			        if (fileinfo.type == OS_FILE_TYPE_DIR
-				    || dbinfo.type == OS_FILE_TYPE_UNKNOWN) {
+			        if (fileinfo.type == OS_FILE_TYPE_DIR) {
+
 				        goto next_file_item;
 				}
 

innobase/os/os0file.c

@@ -700,12 +700,12 @@ http://www.mysql.com/doc/en/Windows_symbolic_links.html */
 		} else if (lpFindFileData->dwFileAttributes
 						& FILE_ATTRIBUTE_DIRECTORY) {
 		        info->type = OS_FILE_TYPE_DIR;
-		} else if (lpFindFileData->dwFileAttributes
-						& FILE_ATTRIBUTE_NORMAL) {
-/* TODO: are FILE_ATTRIBUTE_NORMAL files really all normal files? */	
-			info->type = OS_FILE_TYPE_FILE;
 		} else {
-			info->type = OS_FILE_TYPE_UNKNOWN;
+			/* It is probably safest to assume that all other
+			file types are normal. Better to check them rather
+			than blindly skip them. */
+
+			info->type = OS_FILE_TYPE_FILE;
 		}
 	}