scst_tg: Reject READ and WRITE commands for ports that are in the ALUA state "standby"

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@6519 d57e44dd-8a1f-0410-8b47-8ef2f437770f

scst/README

@@ -1460,10 +1460,6 @@ information about how to associate iSCSI targets with a single physical
 interface.
 
 Notes:
-- The ALUA specification allows but does not require that SCSI READ and WRITE
-  commands are rejected by ports that are not active. SCST processes READ and
-  WRITE commands unless these are received through a port that is in the
-  unavailable, transitioning or offline state.
 - In a H.A. setup it is the responsibility of the user to synchronize ALUA
   information between the individual systems running SCST. There are no
   provisions in SCST to exchange ALUA information automatically between

scst/include/scst_const.h

@@ -291,6 +291,7 @@ static inline int scst_sense_response_code(const uint8_t *sense)
 /* NOT_READY is 2 */
 #define scst_sense_format_in_progress		NOT_READY,       0x04, 0x04
 #define scst_sense_tp_transitioning		NOT_READY,	 0x04, 0x0A
+#define scst_sense_tp_standby			NOT_READY,	 0x04, 0x0B
 #define scst_sense_tp_unav			NOT_READY,	 0x04, 0x0C
 #define scst_sense_no_medium			NOT_READY,       0x3a, 0
 

scst/src/scst_tg.c

@@ -297,6 +297,34 @@ static bool scst_tg_accept(struct scst_cmd *cmd)
 	return false;
 }
 
+/*
+ * Whether or not to accept a command in the ALUA standby state.
+ */
+static bool scst_tg_accept_standby(struct scst_cmd *cmd)
+{
+	bool process_cmd = scst_tg_accept(cmd);
+
+	if (process_cmd)
+		return process_cmd;
+
+	switch (cmd->cdb[0]) {
+	case MODE_SELECT:
+	case MODE_SELECT_10:
+	case LOG_SELECT:
+	case LOG_SENSE:
+	case RECEIVE_DIAGNOSTIC:
+	case SEND_DIAGNOSTIC:
+	case PERSISTENT_RESERVE_IN:
+	case PERSISTENT_RESERVE_OUT:
+		return true;
+	}
+
+	scst_set_cmd_error(cmd, SCST_LOAD_SENSE(scst_sense_tp_standby));
+
+	return false;
+}
+
+
 /*
  * Whether or not to accept a command in the ALUA unavailable state.
  */
@@ -327,7 +355,7 @@ static bool scst_tg_accept_transitioning(struct scst_cmd *cmd)
 static bool (*scst_alua_filter[])(struct scst_cmd *cmd) = {
 	[SCST_TG_STATE_OPTIMIZED]	= NULL,
 	[SCST_TG_STATE_NONOPTIMIZED]	= NULL,
-	[SCST_TG_STATE_STANDBY]		= NULL,
+	[SCST_TG_STATE_STANDBY]		= scst_tg_accept_standby,
 	[SCST_TG_STATE_UNAVAILABLE]	= scst_tg_accept_unav,
 	[SCST_TG_STATE_LBA_DEPENDENT]	= NULL,
 	[SCST_TG_STATE_OFFLINE]		= scst_tg_accept_unav,