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Commit ea7e32be authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

iscsi-target: Do not reject non-immediate CmdSNs exceeding MaxCmdSN 



This patch changes iscsit_sequence_cmd() logic to no longer reject
non-immediate CmdSNs that exceed MaxCmdSN with a protocol error,
but instead silently ignore them.

This is done to correctly follow RFC-3720 Section 3.2.2.1:

   For non-immediate commands, the CmdSN field can take any
   value from ExpCmdSN to MaxCmdSN inclusive.  The target MUST silently
   ignore any non-immediate command outside of this range or non-
   immediate duplicates within the range.

Reported-by: default avatarSantosh Kulkarni <santosh.kulkarni@calsoftinc.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 04f3b31b

drivers/target/iscsi/iscsi_target_core.h

+1 −0
Original line number Diff line number Diff line
@@ -193,6 +193,7 @@ enum recover_cmdsn_ret_table { 
	CMDSN_NORMAL_OPERATION		= 0,

	CMDSN_LOWER_THAN_EXP		= 1,

	CMDSN_HIGHER_THAN_EXP		= 2,

	CMDSN_MAXCMDSN_OVERRUN		= 3,

};



/* Used for iscsi_handle_immediate_data() return values */

drivers/target/iscsi/iscsi_target_util.c

+10 −8
Original line number Diff line number Diff line
@@ -242,9 +242,9 @@ static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cm 
	 */

	if (iscsi_sna_gt(cmdsn, sess->max_cmd_sn)) {

		pr_err("Received CmdSN: 0x%08x is greater than"

		       " MaxCmdSN: 0x%08x, protocol error.\n", cmdsn,

		       " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn,

		       sess->max_cmd_sn);

		ret = CMDSN_ERROR_CANNOT_RECOVER;

		ret = CMDSN_MAXCMDSN_OVERRUN;



	} else if (cmdsn == sess->exp_cmd_sn) {

		sess->exp_cmd_sn++;
@@ -303,14 +303,16 @@ int iscsit_sequence_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd, 
		ret = CMDSN_HIGHER_THAN_EXP;

		break;

	case CMDSN_LOWER_THAN_EXP:

	case CMDSN_MAXCMDSN_OVERRUN:

	default:

		cmd->i_state = ISTATE_REMOVE;

		iscsit_add_cmd_to_immediate_queue(cmd, conn, cmd->i_state);

		ret = cmdsn_ret;

		break;

	default:

		reason = ISCSI_REASON_PROTOCOL_ERROR;

		reject = true;

		ret = cmdsn_ret;

		/*

		 * Existing callers for iscsit_sequence_cmd() will silently

		 * ignore commands with CMDSN_LOWER_THAN_EXP, so force this

		 * return for CMDSN_MAXCMDSN_OVERRUN as well..

		 */

		ret = CMDSN_LOWER_THAN_EXP;

		break;

	}

	mutex_unlock(&conn->sess->cmdsn_mutex);