nfsd4: allow backchannel recovery
Now that we have a list of connections to choose from, we can teach the
callback code to just pick a suitable connection and use that, instead
of insisting on forever using the connection that the first
create_session was sent with.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index dd183af..18b740b 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -473,8 +473,7 @@
/* Reference counting, callback cleanup, etc., all look racy as heck.
* And why is cl_cb_set an atomic? */
-static int setup_callback_client(struct nfs4_client *clp,
- struct nfs4_cb_conn *conn)
+static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
{
struct rpc_timeout timeparms = {
.to_initval = max_cb_time(),
@@ -501,6 +500,10 @@
args.protocol = XPRT_TRANSPORT_TCP;
clp->cl_cb_ident = conn->cb_ident;
} else {
+ if (!conn->cb_xprt)
+ return -EINVAL;
+ clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
+ clp->cl_cb_session = ses;
args.bc_xprt = conn->cb_xprt;
args.prognumber = clp->cl_cb_session->se_cb_prog;
args.protocol = XPRT_TRANSPORT_BC_TCP;
@@ -756,10 +759,27 @@
cb->cb_ops->rpc_release(cb);
}
+/* requires cl_lock: */
+static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
+{
+ struct nfsd4_session *s;
+ struct nfsd4_conn *c;
+
+ list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
+ list_for_each_entry(c, &s->se_conns, cn_persession) {
+ if (c->cn_flags & NFS4_CDFC4_BACK)
+ return c;
+ }
+ }
+ return NULL;
+}
+
static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
{
struct nfs4_cb_conn conn;
struct nfs4_client *clp = cb->cb_clp;
+ struct nfsd4_session *ses = NULL;
+ struct nfsd4_conn *c;
int err;
/*
@@ -770,6 +790,10 @@
rpc_shutdown_client(clp->cl_cb_client);
clp->cl_cb_client = NULL;
}
+ if (clp->cl_cb_conn.cb_xprt) {
+ svc_xprt_put(clp->cl_cb_conn.cb_xprt);
+ clp->cl_cb_conn.cb_xprt = NULL;
+ }
if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags))
return;
spin_lock(&clp->cl_lock);
@@ -780,9 +804,15 @@
BUG_ON(!clp->cl_cb_flags);
clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
+ c = __nfsd4_find_backchannel(clp);
+ if (c) {
+ svc_xprt_get(c->cn_xprt);
+ conn.cb_xprt = c->cn_xprt;
+ ses = c->cn_session;
+ }
spin_unlock(&clp->cl_lock);
- err = setup_callback_client(clp, &conn);
+ err = setup_callback_client(clp, &conn, ses);
if (err)
warn_no_callback_path(clp, err);
}
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 956174f..290370b 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -642,6 +642,7 @@
free_conn(c);
}
spin_unlock(&clp->cl_lock);
+ /* XXX: mark callback for update, probe callback */
}
static struct nfsd4_conn *alloc_conn(struct svc_rqst *rqstp, u32 flags)
@@ -790,16 +791,19 @@
free_session(&new->se_ref);
return NULL;
}
- if (!clp->cl_cb_session && (cses->flags & SESSION4_BACK_CHAN)) {
+ if (cses->flags & SESSION4_BACK_CHAN) {
struct sockaddr *sa = svc_addr(rqstp);
-
- clp->cl_cb_session = new;
- clp->cl_cb_conn.cb_xprt = rqstp->rq_xprt;
- svc_xprt_get(rqstp->rq_xprt);
+ /*
+ * This is a little silly; with sessions there's no real
+ * use for the callback address. Use the peer address
+ * as a reasonable default for now, but consider fixing
+ * the rpc client not to require an address in the
+ * future:
+ */
rpc_copy_addr((struct sockaddr *)&clp->cl_cb_conn.cb_addr, sa);
clp->cl_cb_conn.cb_addrlen = svc_addr_len(sa);
- nfsd4_probe_callback(clp);
}
+ nfsd4_probe_callback(clp);
return new;
}
