From dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 15 Jun 2010 17:25:45 -0400 Subject: [PATCH] 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 --- fs/nfsd/nfs4callback.c | 36 +++++++++++++++++++++++++++++++++--- fs/nfsd/nfs4state.c | 16 ++++++++++------ 2 files changed, 43 insertions(+), 9 deletions(-) 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 @@ 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); } 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 @@ 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; } -- 2.7.4