From 21b75b019983dfa5c2dda588f4b60b4ca69844a4 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 26 Oct 2010 10:07:17 -0400 Subject: nfsd4: fix 4.1 connection registration race If a connection is closed just after a sequence or create_session is sent over it, we could end up trying to register a callback that will never get called since the xprt is already marked dead. Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/svc_xprt.h | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h index bbdb680ffbe9..aea0d438e3c7 100644 --- a/include/linux/sunrpc/svc_xprt.h +++ b/include/linux/sunrpc/svc_xprt.h @@ -82,18 +82,28 @@ struct svc_xprt { struct net *xpt_net; }; -static inline void register_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u) +static inline void unregister_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u) { spin_lock(&xpt->xpt_lock); - list_add(&u->list, &xpt->xpt_users); + list_del_init(&u->list); spin_unlock(&xpt->xpt_lock); } -static inline void unregister_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u) +static inline int register_xpt_user(struct svc_xprt *xpt, struct svc_xpt_user *u) { spin_lock(&xpt->xpt_lock); - list_del_init(&u->list); + if (test_bit(XPT_CLOSE, &xpt->xpt_flags)) { + /* + * The connection is about to be deleted soon (or, + * worse, may already be deleted--in which case we've + * already notified the xpt_users). + */ + spin_unlock(&xpt->xpt_lock); + return -ENOTCONN; + } + list_add(&u->list, &xpt->xpt_users); spin_unlock(&xpt->xpt_lock); + return 0; } int svc_reg_xprt_class(struct svc_xprt_class *); -- cgit v1.2.3