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Commit dcbeaa68 authored by J. Bruce Fields's avatar J. Bruce Fields Committed by J. Bruce Fields
Browse files

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: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
parent 1d1bc8f2

fs/nfsd/nfs4callback.c

+33 −3
Original line number Diff line number Diff line
@@ -473,8 +473,7 @@ static int max_cb_time(void) 
/* 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 @@ static int setup_callback_client(struct nfs4_client *clp, 
		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 @@ static void nfsd4_release_cb(struct nfsd4_callback *cb) 
		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 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb) 
		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 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb) 
	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);

}

fs/nfsd/nfs4state.c

+10 −6
Original line number Diff line number Diff line
@@ -642,6 +642,7 @@ static void nfsd4_conn_lost(struct svc_xpt_user *u) 
		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 @@ static struct nfsd4_session *alloc_init_session(struct svc_rqst *rqstp, struct n 
		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;

}