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

From: Lee Duncan
Date: Wed Nov 23 2022 - 11:47:48 EST


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@xxxxxxxxxx>
---
  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.