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>

1 files changed, 10 insertions, 6 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 956174f488a..290370bc9ae 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;
 }