Hi Santosh,
On Fri, 2013-11-15 at 17:05 +0530, santosh kulkarni wrote:
> Hi,
>
> Is the following an expected behavior for LIO.
>
> For iSCSI PDUs with CmdSN say greater(outside the range basically from
> ExpCmdSN to MaxCmdSN) than MaxCmdsn,LIO is straight away rejecting it as
> protocol error and not accepting further write commands.
>
> ~# dmesg
> [1393323.895597] Received CmdSN: 0x00000155 is greater than MaxCmdSN:
> 0x00000092, protocol error.
> [1393783.532961] Received CmdSN: 0x00000155 is greater than MaxCmdSN:
> 0x00000092, protocol error.
>
> But as per RFC the expected behavior is to silently ignore.
>
> Stating clause 3.2.2.1
>
> 3.2.2.1. Command Numbering and Acknowledging
>
>
> "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"
>
>
> LIO must ignore such PDUs and handle subsequent PDUs.
>
I could have sworn that non-immediate CmdSNs that exceeded MaxCmdSN
should be considered a protocol error, but the wording in 3.2.2.1
clearly states they must be silently ignored..
To that effect, here is the patch that I'm applying for v3.13 code.
Thanks!
--nab
diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h
index f2094d2..8dcb3c1 100644
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -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 */
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 45b8fd1..9064926 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -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);
--
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