Re: [PATCH] scsi:iscsi: Record session's startup mode in kernel

[Wenchao Hao <haowenchao@huawei.com>]

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

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".

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