From edc7a894034acb4c7ff8305716ca5df8aaf8e642 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 22 Mar 2010 15:37:17 -0400 Subject: nfsd: provide callbacks on svc_xprt deletion 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 --- include/linux/sunrpc/svc_xprt.h | 25 +++++++++++++++++++++++++ net/sunrpc/svc_xprt.c | 15 +++++++++++++++ 2 files changed, 40 insertions(+) diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h index bb182979569e..bbdb680ffbe9 100644 --- a/include/linux/sunrpc/svc_xprt.h +++ b/include/linux/sunrpc/svc_xprt.h @@ -33,6 +33,16 @@ 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; @@ -67,10 +77,25 @@ 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 678b6ee4da7b..12025eedc781 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); @@ -881,6 +882,19 @@ 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 */ @@ -913,6 +927,7 @@ 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); } -- cgit v1.2.2