3 files changed, 57 insertions, 4 deletions

diff --git a/drivers/block/rnbd/rnbd-srv-sysfs.c b/drivers/block/rnbd/rnbd-srv-sysfs.c
index 106775c074d1..08ffb492ebfa 100644
--- a/drivers/block/rnbd/rnbd-srv-sysfs.c
+++ b/drivers/block/rnbd/rnbd-srv-sysfs.c
@@ -120,10 +120,46 @@ static ssize_t mapping_path_show(struct kobject *kobj,
 static struct kobj_attribute rnbd_srv_dev_session_mapping_path_attr =
 	__ATTR_RO(mapping_path);
 
+static ssize_t rnbd_srv_dev_session_force_close_show(struct kobject *kobj,
+					struct kobj_attribute *attr, char *page)
+{
+	return scnprintf(page, PAGE_SIZE, "Usage: echo 1 > %s\n",
+			 attr->attr.name);
+}
+
+static ssize_t rnbd_srv_dev_session_force_close_store(struct kobject *kobj,
+					struct kobj_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct rnbd_srv_sess_dev *sess_dev;
+
+	sess_dev = container_of(kobj, struct rnbd_srv_sess_dev, kobj);
+
+	if (!sysfs_streq(buf, "1")) {
+		rnbd_srv_err(sess_dev, "%s: invalid value: '%s'\n",
+			      attr->attr.name, buf);
+		return -EINVAL;
+	}
+
+	rnbd_srv_info(sess_dev, "force close requested\n");
+
+	/* first remove sysfs itself to avoid deadlock */
+	sysfs_remove_file_self(&sess_dev->kobj, &attr->attr);
+	rnbd_srv_sess_dev_force_close(sess_dev);
+
+	return count;
+}
+
+static struct kobj_attribute rnbd_srv_dev_session_force_close_attr =
+	__ATTR(force_close, 0644,
+	       rnbd_srv_dev_session_force_close_show,
+	       rnbd_srv_dev_session_force_close_store);
+
 static struct attribute *rnbd_srv_default_dev_sessions_attrs[] = {
 	&rnbd_srv_dev_session_access_mode_attr.attr,
 	&rnbd_srv_dev_session_ro_attr.attr,
 	&rnbd_srv_dev_session_mapping_path_attr.attr,
+	&rnbd_srv_dev_session_force_close_attr.attr,
 	NULL,
 };
 
@@ -145,7 +181,7 @@ static void rnbd_srv_sess_dev_release(struct kobject *kobj)
 	struct rnbd_srv_sess_dev *sess_dev;
 
 	sess_dev = container_of(kobj, struct rnbd_srv_sess_dev, kobj);
-	rnbd_destroy_sess_dev(sess_dev);
+	rnbd_destroy_sess_dev(sess_dev, sess_dev->keep_id);
 }
 
 static struct kobj_type rnbd_srv_sess_dev_ktype = {
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index e1bc8b4cd592..d1ee72ed8384 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -212,12 +212,20 @@ static void rnbd_put_srv_dev(struct rnbd_srv_dev *dev)
 	kref_put(&dev->kref, destroy_device_cb);
 }
 
-void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev)
+void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev, bool keep_id)
 {
 	DECLARE_COMPLETION_ONSTACK(dc);
 
-	xa_erase(&sess_dev->sess->index_idr, sess_dev->device_id);
+	if (keep_id)
+		/* free the resources for the id but don't  */
+		/* allow to re-use the id itself because it */
+		/* is still used by the client              */
+		xa_cmpxchg(&sess_dev->sess->index_idr, sess_dev->device_id,
+			   sess_dev, NULL, 0);
+	else
+		xa_erase(&sess_dev->sess->index_idr, sess_dev->device_id);
 	synchronize_rcu();
+
 	sess_dev->destroy_comp = &dc;
 	rnbd_put_sess_dev(sess_dev);
 	wait_for_completion(&dc); /* wait for inflights to drop to zero */
@@ -328,6 +336,13 @@ static int rnbd_srv_link_ev(struct rtrs_srv *rtrs,
 	}
 }
 
+void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev)
+{
+	rnbd_srv_destroy_dev_session_sysfs(sess_dev);
+	sess_dev->keep_id = true;
+
+}
+
 static int process_msg_close(struct rtrs_srv *rtrs,
 			     struct rnbd_srv_session *srv_sess,
 			     void *data, size_t datalen, const void *usr,
diff --git a/drivers/block/rnbd/rnbd-srv.h b/drivers/block/rnbd/rnbd-srv.h
index 5a8544b5e74f..b157371c25ed 100644
--- a/drivers/block/rnbd/rnbd-srv.h
+++ b/drivers/block/rnbd/rnbd-srv.h
@@ -56,6 +56,7 @@ struct rnbd_srv_sess_dev {
 	struct rnbd_srv_dev		*dev;
 	struct kobject                  kobj;
 	u32                             device_id;
+	bool				keep_id;
 	fmode_t                         open_flags;
 	struct kref			kref;
 	struct completion               *destroy_comp;
@@ -63,6 +64,7 @@ struct rnbd_srv_sess_dev {
 	enum rnbd_access_mode		access_mode;
 };
 
+void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev);
 /* rnbd-srv-sysfs.c */
 
 int rnbd_srv_create_dev_sysfs(struct rnbd_srv_dev *dev,
@@ -73,6 +75,6 @@ int rnbd_srv_create_dev_session_sysfs(struct rnbd_srv_sess_dev *sess_dev);
 void rnbd_srv_destroy_dev_session_sysfs(struct rnbd_srv_sess_dev *sess_dev);
 int rnbd_srv_create_sysfs_files(void);
 void rnbd_srv_destroy_sysfs_files(void);
-void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev);
+void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev, bool keep_id);
 
 #endif /* RNBD_SRV_H */