-/* pb_flags that apply to all requests */
-#define MSG_LAST_REPLAY 0x0001
-#define MSG_RESENT 0x0002
-#define MSG_REPLAY 0x0004
-/* #define MSG_AT_SUPPORT 0x0008 obsolete 1.5 */
-#define MSG_DELAY_REPLAY 0x0010
-#define MSG_VERSION_REPLAY 0x0020
-#define MSG_REQ_REPLAY_DONE 0x0040
-#define MSG_LOCK_REPLAY_DONE 0x0080
-
-/* pb_op_flags for all connect opcodes (MDS_CONNECT, OST_CONNECT) */
-#define MSG_CONNECT_RECOVERING 0x00000001
-#define MSG_CONNECT_RECONNECT 0x00000002
-#define MSG_CONNECT_REPLAYABLE 0x00000004
-/* #define MSG_CONNECT_PEER 0x00000008 removed 1.5 */
-#define MSG_CONNECT_LIBCLIENT 0x00000010
-#define MSG_CONNECT_INITIAL 0x00000020
-#define MSG_CONNECT_ASYNC 0x00000040
+/* pb_flags that apply to all request messages */
+/* #define MSG_LAST_REPLAY 0x0001 obsolete 2.0 => {REQ,LOCK}_REPLAY_DONE */
+#define MSG_RESENT 0x0002 /* was previously sent, no reply seen */
+#define MSG_REPLAY 0x0004 /* was processed, got reply, recovery */
+/* #define MSG_AT_SUPPORT 0x0008 obsolete since 1.5, AT always enabled */
+/* #define MSG_DELAY_REPLAY 0x0010 obsolete since 2.0 */
+/* #define MSG_VERSION_REPLAY 0x0020 obsolete since 1.8.2, VBR always on */
+#define MSG_REQ_REPLAY_DONE 0x0040 /* request replay over, locks next */
+#define MSG_LOCK_REPLAY_DONE 0x0080 /* lock replay over, client done */
+
+/* pb_op_flags for connect opcodes: MDS_CONNECT, OST_CONNECT, MGS_CONNECT */
+#define MSG_CONNECT_RECOVERING 0x00000001 /* target is in recovery */
+#define MSG_CONNECT_RECONNECT 0x00000002 /* tgt already has client import */
+#define MSG_CONNECT_REPLAYABLE 0x00000004 /* target supports RPC replay */
+/* #define MSG_CONNECT_PEER 0x00000008 obsolete since 1.2, removed in 1.5 */
+#define MSG_CONNECT_LIBCLIENT 0x00000010 /* obsolete since 2.3, removed 2.6 */
+#define MSG_CONNECT_INITIAL 0x00000020 /* first client connection attempt */
+/* #define MSG_CONNECT_ASYNC 0x00000040 obsolete since 1.5 */