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nfsd4: allow backchannel recovery

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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>
This commit is contained in:
J. Bruce Fields 2010-06-15 17:25:45 -04:00 committed by J. Bruce Fields
parent 1d1bc8f207
commit dcbeaa68db
2 changed files with 43 additions and 9 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

36
fs/nfsd/nfs4callback.c
View file

@ -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);
}

16
fs/nfsd/nfs4state.c
View file

@ -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;
}