| Message ID | 20140818062254.1449.26590.stgit@notabene.brown (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 2014-08-18 at 16:22 +1000, NeilBrown wrote: > If requests are being sent to the local host, then NFS will > need to take care to avoid deadlocks. > > So keep track when accepting a connection or sending a UDP request > and set a flag in the svc_xprt when the peer connected to is local. > > The interface rpc_is_foreign() is provided to check is a given client > is connected to a foreign server. When it returns zero it is either > not connected or connected to a local server and in either case > greater care is needed. > > Signed-off-by: NeilBrown <neilb@suse.de> > --- > include/linux/sunrpc/clnt.h | 1 + > include/linux/sunrpc/xprt.h | 1 + > net/sunrpc/clnt.c | 25 +++++++++++++++++++++++++ > net/sunrpc/xprtsock.c | 9 +++++++++ > 4 files changed, 36 insertions(+) > > diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h > index 70736b98c721..cd79b2a28ceb 100644 > --- a/include/linux/sunrpc/clnt.h > +++ b/include/linux/sunrpc/clnt.h > @@ -175,6 +175,7 @@ void rpc_force_rebind(struct rpc_clnt *); > size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t); > const char *rpc_peeraddr2str(struct rpc_clnt *, enum rpc_display_format_t); > int rpc_localaddr(struct rpc_clnt *, struct sockaddr *, size_t); > +int rpc_is_foreign(struct rpc_clnt *); > > #endif /* __KERNEL__ */ > #endif /* _LINUX_SUNRPC_CLNT_H */ > diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h > index fcbfe8783243..6a9dffcb9d3f 100644 > --- a/include/linux/sunrpc/xprt.h > +++ b/include/linux/sunrpc/xprt.h > @@ -357,6 +357,7 @@ int xs_swapper(struct rpc_xprt *xprt, int enable); > #define XPRT_CONNECTION_ABORT (7) > #define XPRT_CONNECTION_CLOSE (8) > #define XPRT_CONGESTED (9) > +#define XPRT_LOCAL (10) > Can we please rename that to XPRT_LOOPBACK or something along those lines? To me XPRT_LOCAL looks a little too close for comfort to AF_LOCAL, which is also a supported transport.
On Wed, 20 Aug 2014 20:33:04 -0400 Trond Myklebust <trond.myklebust@primarydata.com> wrote: > On Mon, 2014-08-18 at 16:22 +1000, NeilBrown wrote: > > If requests are being sent to the local host, then NFS will > > need to take care to avoid deadlocks. > > > > So keep track when accepting a connection or sending a UDP request > > and set a flag in the svc_xprt when the peer connected to is local. > > > > The interface rpc_is_foreign() is provided to check is a given client > > is connected to a foreign server. When it returns zero it is either > > not connected or connected to a local server and in either case > > greater care is needed. > > > > Signed-off-by: NeilBrown <neilb@suse.de> > > --- > > include/linux/sunrpc/clnt.h | 1 + > > include/linux/sunrpc/xprt.h | 1 + > > net/sunrpc/clnt.c | 25 +++++++++++++++++++++++++ > > net/sunrpc/xprtsock.c | 9 +++++++++ > > 4 files changed, 36 insertions(+) > > > > diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h > > index 70736b98c721..cd79b2a28ceb 100644 > > --- a/include/linux/sunrpc/clnt.h > > +++ b/include/linux/sunrpc/clnt.h > > @@ -175,6 +175,7 @@ void rpc_force_rebind(struct rpc_clnt *); > > size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t); > > const char *rpc_peeraddr2str(struct rpc_clnt *, enum rpc_display_format_t); > > int rpc_localaddr(struct rpc_clnt *, struct sockaddr *, size_t); > > +int rpc_is_foreign(struct rpc_clnt *); > > > > #endif /* __KERNEL__ */ > > #endif /* _LINUX_SUNRPC_CLNT_H */ > > diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h > > index fcbfe8783243..6a9dffcb9d3f 100644 > > --- a/include/linux/sunrpc/xprt.h > > +++ b/include/linux/sunrpc/xprt.h > > @@ -357,6 +357,7 @@ int xs_swapper(struct rpc_xprt *xprt, int enable); > > #define XPRT_CONNECTION_ABORT (7) > > #define XPRT_CONNECTION_CLOSE (8) > > #define XPRT_CONGESTED (9) > > +#define XPRT_LOCAL (10) > > > > Can we please rename that to XPRT_LOOPBACK or something along those > lines? To me XPRT_LOCAL looks a little too close for comfort to > AF_LOCAL, which is also a supported transport. > I'm fine with that. I'll resend once we are in agreement about the other bits. Thanks, NeilBrown
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h index 70736b98c721..cd79b2a28ceb 100644 --- a/include/linux/sunrpc/clnt.h +++ b/include/linux/sunrpc/clnt.h @@ -175,6 +175,7 @@ void rpc_force_rebind(struct rpc_clnt *); size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t); const char *rpc_peeraddr2str(struct rpc_clnt *, enum rpc_display_format_t); int rpc_localaddr(struct rpc_clnt *, struct sockaddr *, size_t); +int rpc_is_foreign(struct rpc_clnt *); #endif /* __KERNEL__ */ #endif /* _LINUX_SUNRPC_CLNT_H */ diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index fcbfe8783243..6a9dffcb9d3f 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -357,6 +357,7 @@ int xs_swapper(struct rpc_xprt *xprt, int enable); #define XPRT_CONNECTION_ABORT (7) #define XPRT_CONNECTION_CLOSE (8) #define XPRT_CONGESTED (9) +#define XPRT_LOCAL (10) static inline void xprt_set_connected(struct rpc_xprt *xprt) { diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 488ddeed9363..1559d03e468e 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -1117,6 +1117,31 @@ const char *rpc_peeraddr2str(struct rpc_clnt *clnt, } EXPORT_SYMBOL_GPL(rpc_peeraddr2str); +/** + * rpc_is_foreign - report is rpc client was recently connected to + * remote host + * @clnt: RPC client structure + * + * If the client is not connected, or connected to the local host + * (any IP address), then return 0. Only return non-zero if the + * most recent state was a connection to a remote host. + * For UDP the client always appears to be connected, and the + * remoteness of the host is of the destination of the last transmission. + */ +int rpc_is_foreign(struct rpc_clnt *clnt) +{ + struct rpc_xprt *xprt; + int conn_foreign; + + rcu_read_lock(); + xprt = rcu_dereference(clnt->cl_xprt); + conn_foreign = (xprt && xprt_connected(xprt) + && !test_bit(XPRT_LOCAL, &xprt->state)); + rcu_read_unlock(); + return conn_foreign; +} +EXPORT_SYMBOL_GPL(rpc_is_foreign); + static const struct sockaddr_in rpc_inaddr_loopback = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_ANY), diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 43cd89eacfab..70942643e88c 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -643,6 +643,11 @@ static int xs_udp_send_request(struct rpc_task *task) xdr->len - req->rq_bytes_sent, status); if (status >= 0) { + if (sock_is_loopback(transport->sock->sk)) + set_bit(XPRT_LOCAL, &xprt->state); + else + clear_bit(XPRT_LOCAL, &xprt->state); + req->rq_xmit_bytes_sent += status; if (status >= req->rq_slen) return 0; @@ -1550,6 +1555,10 @@ static void xs_tcp_state_change(struct sock *sk) xprt_wake_pending_tasks(xprt, -EAGAIN); } + if (sock_is_loopback(sk)) + set_bit(XPRT_LOCAL, &xprt->state); + else + clear_bit(XPRT_LOCAL, &xprt->state); spin_unlock(&xprt->transport_lock); break; case TCP_FIN_WAIT1:
If requests are being sent to the local host, then NFS will need to take care to avoid deadlocks. So keep track when accepting a connection or sending a UDP request and set a flag in the svc_xprt when the peer connected to is local. The interface rpc_is_foreign() is provided to check is a given client is connected to a foreign server. When it returns zero it is either not connected or connected to a local server and in either case greater care is needed. Signed-off-by: NeilBrown <neilb@suse.de> --- include/linux/sunrpc/clnt.h | 1 + include/linux/sunrpc/xprt.h | 1 + net/sunrpc/clnt.c | 25 +++++++++++++++++++++++++ net/sunrpc/xprtsock.c | 9 +++++++++ 4 files changed, 36 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html