From: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
NFSv4.1 needs warning when a client tcp connection goes down, if that
connection is being used as a backchannel, so that it can warn the
client that it has lost the backchannel connection.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
---
include/linux/sunrpc/svc_xprt.h | 25 +++++++++++++++++++++++++
net/sunrpc/svc_xprt.c | 15 +++++++++++++++
2 files changed, 40 insertions(+), 0 deletions(-)
diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index e50e3ec..cc90cce 100644
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -32,6 +32,16 @@ struct svc_xprt_class {
u32 xcl_max_payload;
};
+/*
+ * This is embedded in an object that wants a callback before deleting
+ * an xprt; intended for use by NFSv4.1, which needs to know when a
+ * client's tcp connection (and hence possibly a backchannel) goes away.
+ */
+struct svc_xpt_user {
+ struct list_head list;
+ void (*callback)(struct svc_xpt_user *);
+};
+
struct svc_xprt {
struct svc_xprt_class *xpt_class;
struct svc_xprt_ops *xpt_ops;
@@ -66,10 +76,25 @@ struct svc_xprt {
struct sockaddr_storage xpt_remote; /* remote peer's address */
size_t xpt_remotelen; /* length of address */
struct rpc_wait_queue xpt_bc_pending; /* backchannel wait queue */
+ struct list_head xpt_users; /* callbacks on free */
struct net *xpt_net;
};
+static inline void register_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u)
+{
+ spin_lock(&xpt->xpt_lock);
+ list_add(&u->list, &xpt->xpt_users);
+ spin_unlock(&xpt->xpt_lock);
+}
+
+static inline void unregister_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u)
+{
+ spin_lock(&xpt->xpt_lock);
+ list_del_init(&u->list);
+ spin_unlock(&xpt->xpt_lock);
+}
+
int svc_reg_xprt_class(struct svc_xprt_class *);
void svc_unreg_xprt_class(struct svc_xprt_class *);
void svc_xprt_init(struct svc_xprt_class *, struct svc_xprt *,
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index f7e8915..b37fd3a 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -156,6 +156,7 @@ void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt,
INIT_LIST_HEAD(&xprt->xpt_list);
INIT_LIST_HEAD(&xprt->xpt_ready);
INIT_LIST_HEAD(&xprt->xpt_deferred);
+ INIT_LIST_HEAD(&xprt->xpt_users);
mutex_init(&xprt->xpt_mutex);
spin_lock_init(&xprt->xpt_lock);
set_bit(XPT_BUSY, &xprt->xpt_flags);
@@ -880,6 +881,19 @@ static void svc_age_temp_xprts(unsigned long closure)
mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
}
+static void call_xpt_users(struct svc_xprt *xprt)
+{
+ struct svc_xpt_user *u;
+
+ spin_lock(&xprt->xpt_lock);
+ while (!list_empty(&xprt->xpt_users)) {
+ u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
+ list_del(&u->list);
+ u->callback(u);
+ }
+ spin_unlock(&xprt->xpt_lock);
+}
+
/*
* Remove a dead transport
*/
@@ -912,6 +926,7 @@ void svc_delete_xprt(struct svc_xprt *xprt)
while ((dr = svc_deferred_dequeue(xprt)) != NULL)
kfree(dr);
+ call_xpt_users(xprt);
svc_xprt_put(xprt);
}
--
1.7.0.4
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