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Date:   Wed, 23 Nov 2022 08:47:30 -0800
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Subject: Re: [PATCH] scsi:iscsi: Record session's startup mode in kernel
Content-Language: en-US
To:     Wenchao Hao <haowenchao@huawei.com>,
        Chris Leech <cleech@redhat.com>,
        Mike Christie <michael.christie@oracle.com>,
        "James E . J . Bottomley" <jejb@linux.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        open-iscsi@googlegroups.com, linux-scsi@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, liuzhiqiang26@huawei.com,
        linfeilong@huawei.com
References: <20221122213040.4128105-1-haowenchao@huawei.com>
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 <00f11c61-a53f-c48a-017f-4c06055ea708@huawei.com>
From:   Lee Duncan <lduncan@suse.com>
In-Reply-To: <00f11c61-a53f-c48a-017f-4c06055ea708@huawei.com>
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On 11/22/22 20:41, Wenchao Hao wrote:
> On 2022/11/23 4:00, Lee Duncan wrote:
>> On 11/22/22 13:30, Wenchao Hao wrote:
>>> There are 3 iscsi session's startup mode which are onboot, manual and
>>> automatic. We can boot from iSCSI disks with help of dracut's service
>>> in initrd, which would set node's startup mode to onboot, then create
>>> iSCSI sessions.
>>>
>>> While the configure of onboot mode is recorded in file of initrd stage
>>> and would be lost when switch to rootfs. Even if we update the startup
>>> mode to onboot by hand after switch to rootfs, it is possible that the
>>> configure would be covered by another discovery command.
>>>
>>> root would be mounted on iSCSI disks when boot from iSCSI disks, if the
>>> sessions is logged out, the related disks would be removed, which would
>>> cause the whole system halt.
>>>
>>> So we need record session's start up mode in kernel and check this
>>> mode before logout this session.
>>>
>>> Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
>>> ---
>>>    drivers/infiniband/ulp/iser/iscsi_iser.c | 1 +
>>>    drivers/scsi/be2iscsi/be_iscsi.c         | 1 +
>>>    drivers/scsi/bnx2i/bnx2i_iscsi.c         | 1 +
>>>    drivers/scsi/cxgbi/libcxgbi.c            | 1 +
>>>    drivers/scsi/iscsi_tcp.c                 | 1 +
>>>    drivers/scsi/libiscsi.c                  | 5 +++++
>>>    drivers/scsi/qedi/qedi_iscsi.c           | 1 +
>>>    drivers/scsi/qla4xxx/ql4_os.c            | 1 +
>>>    drivers/scsi/scsi_transport_iscsi.c      | 4 ++++
>>>    include/scsi/iscsi_if.h                  | 1 +
>>>    include/scsi/libiscsi.h                  | 1 +
>>>    11 files changed, 18 insertions(+)
>>>
>>> diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
>>> index 620ae5b2d80d..778c023673ea 100644
>>> --- a/drivers/infiniband/ulp/iser/iscsi_iser.c
>>> +++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
>>> @@ -947,6 +947,7 @@ static umode_t iser_attr_is_visible(int param_type, int param)
>>>            case ISCSI_PARAM_IFACE_NAME:
>>>            case ISCSI_PARAM_INITIATOR_NAME:
>>>            case ISCSI_PARAM_DISCOVERY_SESS:
>>> +        case ISCSI_PARAM_NODE_STARTUP:
>>>                return S_IRUGO;
>>>            default:
>>>                return 0;
>>> diff --git a/drivers/scsi/be2iscsi/be_iscsi.c b/drivers/scsi/be2iscsi/be_iscsi.c
>>> index 8aeaddc93b16..a21a4d9ab8b8 100644
>>> --- a/drivers/scsi/be2iscsi/be_iscsi.c
>>> +++ b/drivers/scsi/be2iscsi/be_iscsi.c
>>> @@ -1401,6 +1401,7 @@ umode_t beiscsi_attr_is_visible(int param_type, int param)
>>>            case ISCSI_PARAM_LU_RESET_TMO:
>>>            case ISCSI_PARAM_IFACE_NAME:
>>>            case ISCSI_PARAM_INITIATOR_NAME:
>>> +        case ISCSI_PARAM_NODE_STARTUP:
>>>                return S_IRUGO;
>>>            default:
>>>                return 0;
>>> diff --git a/drivers/scsi/bnx2i/bnx2i_iscsi.c b/drivers/scsi/bnx2i/bnx2i_iscsi.c
>>> index a3c800e04a2e..d1fb06d8a92e 100644
>>> --- a/drivers/scsi/bnx2i/bnx2i_iscsi.c
>>> +++ b/drivers/scsi/bnx2i/bnx2i_iscsi.c
>>> @@ -2237,6 +2237,7 @@ static umode_t bnx2i_attr_is_visible(int param_type, int param)
>>>            case ISCSI_PARAM_BOOT_ROOT:
>>>            case ISCSI_PARAM_BOOT_NIC:
>>>            case ISCSI_PARAM_BOOT_TARGET:
>>> +        case ISCSI_PARAM_NODE_STARTUP:
>>>                return S_IRUGO;
>>>            default:
>>>                return 0;
>>> diff --git a/drivers/scsi/cxgbi/libcxgbi.c b/drivers/scsi/cxgbi/libcxgbi.c
>>> index af281e271f88..111b2ac78964 100644
>>> --- a/drivers/scsi/cxgbi/libcxgbi.c
>>> +++ b/drivers/scsi/cxgbi/libcxgbi.c
>>> @@ -3063,6 +3063,7 @@ umode_t cxgbi_attr_is_visible(int param_type, int param)
>>>            case ISCSI_PARAM_TGT_RESET_TMO:
>>>            case ISCSI_PARAM_IFACE_NAME:
>>>            case ISCSI_PARAM_INITIATOR_NAME:
>>> +        case ISCSI_PARAM_NODE_STARTUP:
>>>                return S_IRUGO;
>>>            default:
>>>                return 0;
>>> diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
>>> index 5fb1f364e815..47a73fb3e4b0 100644
>>> --- a/drivers/scsi/iscsi_tcp.c
>>> +++ b/drivers/scsi/iscsi_tcp.c
>>> @@ -1036,6 +1036,7 @@ static umode_t iscsi_sw_tcp_attr_is_visible(int param_type, int param)
>>>            case ISCSI_PARAM_TGT_RESET_TMO:
>>>            case ISCSI_PARAM_IFACE_NAME:
>>>            case ISCSI_PARAM_INITIATOR_NAME:
>>> +        case ISCSI_PARAM_NODE_STARTUP:
>>>                return S_IRUGO;
>>>            default:
>>>                return 0;
>>> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
>>> index d95f4bcdeb2e..1f2b0a9a029e 100644
>>> --- a/drivers/scsi/libiscsi.c
>>> +++ b/drivers/scsi/libiscsi.c
>>> @@ -3576,6 +3576,8 @@ int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
>>>            break;
>>>        case ISCSI_PARAM_LOCAL_IPADDR:
>>>            return iscsi_switch_str_param(&conn->local_ipaddr, buf);
>>> +    case ISCSI_PARAM_NODE_STARTUP:
>>> +        return iscsi_switch_str_param(&session->node_startup, buf);
>>>        default:
>>>            return -ENOSYS;
>>>        }
>>> @@ -3712,6 +3714,9 @@ int iscsi_session_get_param(struct iscsi_cls_session *cls_session,
>>>            else
>>>                len = sysfs_emit(buf, "\n");
>>>            break;
>>> +    case ISCSI_PARAM_NODE_STARTUP:
>>> +        len = sysfs_emit(buf, "%s\n", session->node_startup);
>>> +        break;
>>>        default:
>>>            return -ENOSYS;
>>>        }
>>> diff --git a/drivers/scsi/qedi/qedi_iscsi.c b/drivers/scsi/qedi/qedi_iscsi.c
>>> index 31ec429104e2..b947a5bca380 100644
>>> --- a/drivers/scsi/qedi/qedi_iscsi.c
>>> +++ b/drivers/scsi/qedi/qedi_iscsi.c
>>> @@ -1437,6 +1437,7 @@ static umode_t qedi_attr_is_visible(int param_type, int param)
>>>            case ISCSI_PARAM_BOOT_ROOT:
>>>            case ISCSI_PARAM_BOOT_NIC:
>>>            case ISCSI_PARAM_BOOT_TARGET:
>>> +        case ISCSI_PARAM_NODE_STARTUP:
>>>                return 0444;
>>>            default:
>>>                return 0;
>>> diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c
>>> index 9e849f6b0d0f..1cb7c6dbe9d3 100644
>>> --- a/drivers/scsi/qla4xxx/ql4_os.c
>>> +++ b/drivers/scsi/qla4xxx/ql4_os.c
>>> @@ -468,6 +468,7 @@ static umode_t qla4_attr_is_visible(int param_type, int param)
>>>            case ISCSI_PARAM_DISCOVERY_PARENT_IDX:
>>>            case ISCSI_PARAM_DISCOVERY_PARENT_TYPE:
>>>            case ISCSI_PARAM_LOCAL_IPADDR:
>>> +        case ISCSI_PARAM_NODE_STARTUP:
>>>                return S_IRUGO;
>>>            default:
>>>                return 0;
>>> diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
>>> index c3fe5ecfee59..39c14d2a8aad 100644
>>> --- a/drivers/scsi/scsi_transport_iscsi.c
>>> +++ b/drivers/scsi/scsi_transport_iscsi.c
>>> @@ -4367,6 +4367,7 @@ iscsi_session_attr(tsid, ISCSI_PARAM_TSID, 0);
>>>    iscsi_session_attr(def_taskmgmt_tmo, ISCSI_PARAM_DEF_TASKMGMT_TMO, 0);
>>>    iscsi_session_attr(discovery_parent_idx, ISCSI_PARAM_DISCOVERY_PARENT_IDX, 0);
>>>    iscsi_session_attr(discovery_parent_type, ISCSI_PARAM_DISCOVERY_PARENT_TYPE, 0);
>>> +iscsi_session_attr(node_startup, ISCSI_PARAM_NODE_STARTUP, 0);
>>>      static ssize_t
>>>    show_priv_session_state(struct device *dev, struct device_attribute *attr,
>>> @@ -4488,6 +4489,7 @@ static struct attribute *iscsi_session_attrs[] = {
>>>        &dev_attr_sess_def_taskmgmt_tmo.attr,
>>>        &dev_attr_sess_discovery_parent_idx.attr,
>>>        &dev_attr_sess_discovery_parent_type.attr,
>>> +    &dev_attr_sess_node_startup.attr,
>>>        NULL,
>>>    };
>>>    @@ -4587,6 +4589,8 @@ static umode_t iscsi_session_attr_is_visible(struct kobject *kobj,
>>>            return S_IRUGO;
>>>        else if (attr == &dev_attr_priv_sess_target_id.attr)
>>>            return S_IRUGO;
>>> +    else if (attr == &dev_attr_sess_node_startup.attr)
>>> +        param = ISCSI_PARAM_NODE_STARTUP;
>>>        else {
>>>            WARN_ONCE(1, "Invalid session attr");
>>>            return 0;
>>> diff --git a/include/scsi/iscsi_if.h b/include/scsi/iscsi_if.h
>>> index 5225a23f2d0e..e46e69c1fd02 100644
>>> --- a/include/scsi/iscsi_if.h
>>> +++ b/include/scsi/iscsi_if.h
>>> @@ -610,6 +610,7 @@ enum iscsi_param {
>>>        ISCSI_PARAM_DISCOVERY_PARENT_IDX,
>>>        ISCSI_PARAM_DISCOVERY_PARENT_TYPE,
>>>        ISCSI_PARAM_LOCAL_IPADDR,
>>> +    ISCSI_PARAM_NODE_STARTUP,
>>>        /* must always be last */
>>>        ISCSI_PARAM_MAX,
>>>    };
>>> diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
>>> index 654cc3918c94..af4ccdcc1140 100644
>>> --- a/include/scsi/libiscsi.h
>>> +++ b/include/scsi/libiscsi.h
>>> @@ -327,6 +327,7 @@ struct iscsi_session {
>>>        char            *boot_target;
>>>        char            *portal_type;
>>>        char            *discovery_parent_type;
>>> +    char            *node_startup;
>>>        uint16_t        discovery_parent_idx;
>>>        uint16_t        def_taskmgmt_tmo;
>>>        uint16_t        tsid;
>>
>> The iscsiadm/iscsid tools refuse to logout of an ONBOOT session.
>>
> 
> Sorry I did not highlight the key points. The root reason we need to record
> node_startup mode in kernel is userspace's node_startup mode is unreliable in
> some scenarios:
> 
> 1. iscsi node and session is created in initrd, the configure files of these
>     nodes would be lost after we switch to rootfs

That is not my experience. When I boot from iscsi root, after the system 
is running, if I tell the iscsiadm to logout of the root iscsi target it 
refuses. I will test again to verify.

> 2. someone do iscsiadm -m discovery but did not specify the operation mode,
>     the iscsi node's node_startup would be updated to which specified in iscsid.conf

The default on iscsiadm discovery mode is to replace the info on a 
discovered target, but there are other modes. And they don't effect the 
current (root) session.

> 3. someone do iscsiadm -m node -o update to update nodes' configure

Again, does not effect the currently-running session, and can be 
considered shooting oneself in the foot.

> 
> What's more, it seems "iscsiadm/iscsid" only refuse to logout of an ONBOOT
> session when logout is specificed by "--logoutall". We still can logout an
> ONBOOT session with "iscsiadm -m node -u comamnd".

Again, I don't believe that's correct. I will test it.

> 
> Based on these analysis, I think we should record the node_startup mode in kernel
> and check in userspace to avoid logout ONBOOT sessions.