configfs does not work well when the kernel is initiating the creation
of an object we want to export info for and the objects above/below it
are created by the user. There are races/bugs like seen with this patch
and the issue the original bug was trying to fix:
commit f19e4ed1e1edbfa3c9ccb9fed17759b7d6db24c6
Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Date: Thu Aug 29 23:13:30 2019 -0400
configfs_register_group() shouldn't be (and isn't) called in
rmdirable parts
The problem is that for many drivers like qla2xxx, iscsi, etc, session
creation is done by the kernel when there is a login initiated by an
initiator, but we need a common way to export the systems sessions so
tools like targetcli can report basic info like what initaitors are
logged in and daemons like tcmu-runner can track sessions for load
balancing and PGRs.
This patch begins to add a sysfs interface that will initially be used
to export LIO's sessions. The general layout will mirror the lio
configfs tree:
scsi_target/
├── $fabric_driver
│ └── $target_name
│ ├── tpgt_1
│ │ └── sessions
│ └── tpgt_2
│ └── sessions
└── sessions
iscsi example:
scsi_target/
├── iscsi
│ └── iqn.1999-09.com.tcmu:ceph
│ ├── tpgt_1
│ │ └── sessions
│ └── tpgt_2
│ └── sessions
└── sessions
This initial patch adds only adds the upper layer dirs above the
sessions.
Signed-off-by: Mike Christie <mchristi@xxxxxxxxxx>
---
V2:
- rename top level dir to scsi_target
V3:
- delay tpg deletion to allow fabric modules time to remove their
sessions.
- Added root sessions dir for easier lookup if userspace has the
session id.
drivers/target/target_core_configfs.c | 30 +++++++++++++++++++++
drivers/target/target_core_fabric_configfs.c | 40 ++++++++++++++++++++++++++++
drivers/target/target_core_internal.h | 1 +
include/target/target_core_base.h | 4 +++
4 files changed, 75 insertions(+)
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index e6e1755..20aa58b 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -63,6 +63,9 @@
pr_debug("Setup generic %s\n", __stringify(_name)); \
}
+static struct kobject *tcm_core_kobj;
+static struct kobject *tcm_core_sessions_kobj;
+
extern struct t10_alua_lu_gp *default_lu_gp;
static LIST_HEAD(g_tf_list);
@@ -245,6 +248,11 @@ static struct config_group *target_core_register_fabric(
}
pr_debug("Target_Core_ConfigFS: REGISTER -> Located fabric:"
" %s\n", tf->tf_ops->fabric_name);
+
+ tf->kobj = kobject_create_and_add(name, tcm_core_kobj);
+ if (!tf->kobj)
+ goto dec_tf;
+
/*
* On a successful target_core_get_fabric() look, the returned
* struct target_fabric_configfs *tf will contain a usage reference.
@@ -261,6 +269,10 @@ static struct config_group *target_core_register_fabric(
pr_debug("Target_Core_ConfigFS: REGISTER -> Allocated Fabric: %s\n",
config_item_name(&tf->tf_group.cg_item));
return &tf->tf_group;
+
+dec_tf:
+ atomic_dec(&tf->tf_access_cnt);
+ return ERR_PTR(-EINVAL);
}
/*
@@ -283,6 +295,9 @@ static void target_core_deregister_fabric(
pr_debug("Target_Core_ConfigFS: DEREGISTER -> Releasing ci"
" %s\n", config_item_name(item));
+ kobject_del(tf->kobj);
+ kobject_put(tf->kobj);
+
configfs_remove_default_groups(&tf->tf_group);
config_item_put(item);
}
@@ -3536,6 +3551,15 @@ static int __init target_core_init_configfs(void)
target_init_dbroot();
+ tcm_core_kobj = kobject_create_and_add("scsi_target", NULL);
+ if (!tcm_core_kobj)
+ goto out;
+
+ tcm_core_sessions_kobj = kobject_create_and_add("sessions",
+ tcm_core_kobj);
+ if (!tcm_core_sessions_kobj)
+ goto out;
+
return 0;
out:
@@ -3553,6 +3577,12 @@ static int __init target_core_init_configfs(void)
static void __exit target_core_exit_configfs(void)
{
+ kobject_del(tcm_core_sessions_kobj);
+ kobject_put(tcm_core_sessions_kobj);
+
+ kobject_del(tcm_core_kobj);
+ kobject_put(tcm_core_kobj);
+
configfs_remove_default_groups(&alua_lu_gps_group);
configfs_remove_default_groups(&alua_group);
configfs_remove_default_groups(&target_core_hbagroup);
diff --git a/drivers/target/target_core_fabric_configfs.c b/drivers/target/target_core_fabric_configfs.c
index ee85602..efa01b3 100644
--- a/drivers/target/target_core_fabric_configfs.c
+++ b/drivers/target/target_core_fabric_configfs.c
@@ -807,8 +807,23 @@ static void target_fabric_tpg_release(struct config_item *item)
struct se_portal_group, tpg_group);
struct se_wwn *wwn = se_tpg->se_tpg_wwn;
struct target_fabric_configfs *tf = wwn->wwn_tf;
+ struct kobject *sess_kobj, *tpg_kobj;
+
+ /*
+ * Some fabric modules remove the session from the drop_tpg
+ * callout, so remove these parent dirs until after the session
+ * is removed.
+ */
+ sess_kobj = se_tpg->sessions_kobj;
+ tpg_kobj = se_tpg->kobj;
tf->tf_ops->fabric_drop_tpg(se_tpg);
+
+ kobject_del(sess_kobj);
+ kobject_put(sess_kobj);
+
+ kobject_del(tpg_kobj);
+ kobject_put(tpg_kobj);
}
static struct configfs_item_operations target_fabric_tpg_base_item_ops = {
@@ -838,6 +853,14 @@ static struct config_group *target_fabric_make_tpg(
if (!se_tpg || IS_ERR(se_tpg))
return ERR_PTR(-EINVAL);
+ se_tpg->kobj = kobject_create_and_add(name, wwn->kobj);
+ if (!se_tpg->kobj)
+ goto drop_tpg;
+
+ se_tpg->sessions_kobj = kobject_create_and_add("sessions", se_tpg->kobj);
+ if (!se_tpg->sessions_kobj)
+ goto del_tpg_kobj;
+
config_group_init_type_name(&se_tpg->tpg_group, name,
&tf->tf_tpg_base_cit);
@@ -872,6 +895,13 @@ static struct config_group *target_fabric_make_tpg(
&se_tpg->tpg_group);
return &se_tpg->tpg_group;
+
+del_tpg_kobj:
+ kobject_del(se_tpg->kobj);
+ kobject_put(se_tpg->kobj);
+drop_tpg:
+ tf->tf_ops->fabric_drop_tpg(se_tpg);
+ return ERR_PTR(-EINVAL);
}
static void target_fabric_drop_tpg(
@@ -927,6 +957,7 @@ static struct config_group *target_fabric_make_wwn(
struct target_fabric_configfs *tf = container_of(group,
struct target_fabric_configfs, tf_group);
struct se_wwn *wwn;
+ int ret;
if (!tf->tf_ops->fabric_make_wwn) {
pr_err("tf->tf_ops.fabric_make_wwn is NULL\n");
@@ -938,6 +969,9 @@ static struct config_group *target_fabric_make_wwn(
return ERR_PTR(-EINVAL);
wwn->wwn_tf = tf;
+ wwn->kobj = kobject_create_and_add(name, tf->kobj);
+ if (!wwn->kobj)
+ goto drop_wwn;
config_group_init_type_name(&wwn->wwn_group, name, &tf->tf_tpg_cit);
@@ -948,6 +982,10 @@ static struct config_group *target_fabric_make_wwn(
if (tf->tf_ops->add_wwn_groups)
tf->tf_ops->add_wwn_groups(wwn);
return &wwn->wwn_group;
+
+drop_wwn:
+ tf->tf_ops->fabric_drop_wwn(wwn);
+ return ERR_PTR(ret);
}
static void target_fabric_drop_wwn(
@@ -957,6 +995,8 @@ static void target_fabric_drop_wwn(
struct se_wwn *wwn = container_of(to_config_group(item),
struct se_wwn, wwn_group);
+ kobject_del(wwn->kobj);
+ kobject_put(wwn->kobj);
configfs_remove_default_groups(&wwn->wwn_group);
config_item_put(item);
}
diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index 5e016aa..aea50f1 100644
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -27,6 +27,7 @@ struct target_backend {
struct target_fabric_configfs {
atomic_t tf_access_cnt;
struct list_head tf_list;
+ struct kobject *kobj;
struct config_group tf_group;
struct config_group tf_disc_group;
const struct target_core_fabric_ops *tf_ops;
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index d4a588d..16d2a4c 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -8,6 +8,7 @@
#include <linux/percpu-refcount.h>
#include <linux/semaphore.h> /* struct semaphore */
#include <linux/completion.h>
+#include <linux/kobject.h>
#define TARGET_CORE_VERSION "v5.0"
@@ -897,6 +898,8 @@ struct se_portal_group {
/* Pointer to $FABRIC_MOD dependent code */
const struct target_core_fabric_ops *se_tpg_tfo;
struct se_wwn *se_tpg_wwn;
+ struct kobject *kobj;
+ struct kobject *sessions_kobj;
struct config_group tpg_group;
struct config_group tpg_lun_group;
struct config_group tpg_np_group;
@@ -935,6 +938,7 @@ struct se_wwn {
void *priv;
struct config_group wwn_group;
struct config_group fabric_stat_group;
+ struct kobject *kobj;
};
static inline void atomic_inc_mb(atomic_t *v)
--
1.8.3.1
