3 files changed, 63 insertions, 27 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 07c3be6eea64..a269dbeff150 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -284,7 +284,7 @@ nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p,
         struct xdr_stream xdr;
         struct nfs4_delegation *args = cb->cb_op;
         struct nfs4_cb_compound_hdr hdr = {
-                .ident = args->dl_ident,
+                .ident = cb->cb_clp->cl_cb_ident,
                 .minorversion = cb->cb_minorversion,
         };
 
@@ -506,7 +506,8 @@ int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
                         PTR_ERR(client));
                 return PTR_ERR(client);
         }
-        nfsd4_set_callback_client(clp, client);
+        clp->cl_cb_ident = conn->cb_ident;
+        clp->cl_cb_client = client;
         return 0;
 
 }
@@ -569,15 +570,12 @@ void do_probe_callback(struct nfs4_client *clp)
  */
 void nfsd4_probe_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 {
-        int status;
-
         BUG_ON(atomic_read(&clp->cl_cb_set));
 
-        status = setup_callback_client(clp, conn);
-        if (status) {
-                warn_no_callback_path(clp, status);
-                return;
-        }
+        spin_lock(&clp->cl_lock);
+        memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
+        set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
+        spin_unlock(&clp->cl_lock);
         do_probe_callback(clp);
 }
 
@@ -730,19 +728,16 @@ void nfsd4_destroy_callback_queue(void)
 }
 
 /* must be called under the state lock */
-void nfsd4_set_callback_client(struct nfs4_client *clp, struct rpc_clnt *new)
+void nfsd4_shutdown_callback(struct nfs4_client *clp)
 {
-        struct rpc_clnt *old = clp->cl_cb_client;
-
-        clp->cl_cb_client = new;
+        set_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags);
         /*
-         * After this, any work that saw the old value of cl_cb_client will
-         * be gone:
+         * Note this won't actually result in a null callback;
+         * instead, nfsd4_do_callback_rpc() will detect the killed
+         * client, destroy the rpc client, and stop:
          */
+        do_probe_callback(clp);
         flush_workqueue(callback_wq);
-        /* So we can safely shut it down: */
-        if (old)
-                rpc_shutdown_client(old);
 }
 
 void nfsd4_release_cb(struct nfsd4_callback *cb)
@@ -751,15 +746,51 @@ void nfsd4_release_cb(struct nfsd4_callback *cb)
                 cb->cb_ops->rpc_release(cb);
 }
 
+void nfsd4_process_cb_update(struct nfsd4_callback *cb)
+{
+        struct nfs4_cb_conn conn;
+        struct nfs4_client *clp = cb->cb_clp;
+        int err;
+
+        /*
+         * This is either an update, or the client dying; in either case,
+         * kill the old client:
+         */
+        if (clp->cl_cb_client) {
+                rpc_shutdown_client(clp->cl_cb_client);
+                clp->cl_cb_client = NULL;
+        }
+        if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags))
+                return;
+        spin_lock(&clp->cl_lock);
+        /*
+         * Only serialized callback code is allowed to clear these
+         * flags; main nfsd code can only set them:
+         */
+        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));
+        spin_unlock(&clp->cl_lock);
+
+        err = setup_callback_client(clp, &conn);
+        if (err)
+                warn_no_callback_path(clp, err);
+}
+
 void nfsd4_do_callback_rpc(struct work_struct *w)
 {
         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
         struct nfs4_client *clp = cb->cb_clp;
-        struct rpc_clnt *clnt = clp->cl_cb_client;
+        struct rpc_clnt *clnt;
 
-        if (clnt == NULL) {
+        if (clp->cl_cb_flags)
+                nfsd4_process_cb_update(cb);
+
+        clnt = clp->cl_cb_client;
+        if (!clnt) {
+                /* Callback channel broken, or client killed; give up: */
                 nfsd4_release_cb(cb);
-                return; /* Client is shutting down; give up. */
+                return;
         }
         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
                         cb->cb_ops, cb);
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 2f464fb26afc..d3f12dcc1696 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -207,7 +207,6 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_f
 {
         struct nfs4_delegation *dp;
         struct nfs4_file *fp = stp->st_file;
-        struct nfs4_cb_conn *conn = &stp->st_stateowner->so_client->cl_cb_conn;
 
         dprintk("NFSD alloc_init_deleg\n");
         /*
@@ -234,7 +233,6 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_f
         nfs4_file_get_access(fp, O_RDONLY);
         dp->dl_flock = NULL;
         dp->dl_type = type;
-        dp->dl_ident = conn->cb_ident;
         dp->dl_stateid.si_boot = boot_time;
         dp->dl_stateid.si_stateownerid = current_delegid++;
         dp->dl_stateid.si_fileid = 0;
@@ -875,7 +873,7 @@ expire_client(struct nfs4_client *clp)
                 sop = list_entry(clp->cl_openowners.next, struct nfs4_stateowner, so_perclient);
                 release_openowner(sop);
         }
-        nfsd4_set_callback_client(clp, NULL);
+        nfsd4_shutdown_callback(clp);
         if (clp->cl_cb_conn.cb_xprt)
                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
         list_del(&clp->cl_idhash);
@@ -978,6 +976,7 @@ static struct nfs4_client *create_client(struct xdr_netobj name, char *recdir,
         INIT_LIST_HEAD(&clp->cl_delegations);
         INIT_LIST_HEAD(&clp->cl_sessions);
         INIT_LIST_HEAD(&clp->cl_lru);
+        spin_lock_init(&clp->cl_lock);
         INIT_WORK(&clp->cl_cb_null.cb_work, nfsd4_do_callback_rpc);
         clp->cl_time = get_seconds();
         clear_bit(0, &clp->cl_cb_slot_busy);
@@ -1547,7 +1546,7 @@ nfsd4_destroy_session(struct svc_rqst *r,
 
         nfs4_lock_state();
         /* wait for callbacks */
-        nfsd4_set_callback_client(ses->se_client, NULL);
+        nfsd4_shutdown_callback(ses->se_client);
         nfs4_unlock_state();
         nfsd4_put_session(ses);
         status = nfs_ok;
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 2ece6bee65f7..58bc2a63ca14 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -84,7 +84,6 @@ struct nfs4_delegation {
         u32                     dl_type;
         time_t                  dl_time;
 /* For recall: */
-        u32                     dl_ident;
         stateid_t               dl_stateid;
         struct knfsd_fh         dl_fh;
         int                     dl_retries;
@@ -217,10 +216,17 @@ struct nfs4_client {
 
         /* for v4.0 and v4.1 callbacks: */
         struct nfs4_cb_conn     cl_cb_conn;
+#define NFSD4_CLIENT_CB_UPDATE  1
+#define NFSD4_CLIENT_KILL       2
+        unsigned long           cl_cb_flags;
         struct rpc_clnt         *cl_cb_client;
+        u32                     cl_cb_ident;
         atomic_t                cl_cb_set;
         struct nfsd4_callback   cl_cb_null;
 
+        /* for all client information that callback code might need: */
+        spinlock_t              cl_lock;
+
         /* for nfs41 */
         struct list_head        cl_sessions;
         struct nfsd4_clid_slot  cl_cs_slot;     /* create_session slot */
@@ -439,7 +445,7 @@ extern void nfsd4_do_callback_rpc(struct work_struct *);
 extern void nfsd4_cb_recall(struct nfs4_delegation *dp);
 extern int nfsd4_create_callback_queue(void);
 extern void nfsd4_destroy_callback_queue(void);
-extern void nfsd4_set_callback_client(struct nfs4_client *, struct rpc_clnt *);
+extern void nfsd4_shutdown_callback(struct nfs4_client *);
 extern void nfs4_put_delegation(struct nfs4_delegation *dp);
 extern __be32 nfs4_make_rec_clidname(char *clidname, struct xdr_netobj *clname);
 extern void nfsd4_init_recdir(char *recdir_name);