nfsd4: fix callback restarting

Ensure a new callback is added to the client's list of callbacks at most
once.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 9 insertions, 12 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 209e186386a0..ae93c5c83e87 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -639,9 +639,12 @@ static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
                 if (!nfsd41_cb_get_slot(clp, task))
                         return;
         }
-        cb->cb_done = false;
         spin_lock(&clp->cl_lock);
-        list_add(&cb->cb_per_client, &clp->cl_callbacks);
+        if (list_empty(&cb->cb_per_client)) {
+                /* This is the first call, not a restart */
+                cb->cb_done = false;
+                list_add(&cb->cb_per_client, &clp->cl_callbacks);
+        }
         spin_unlock(&clp->cl_lock);
         rpc_call_start(task);
 }
@@ -678,10 +681,10 @@ static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 
         nfsd4_cb_done(task, calldata);
 
-        if (current_rpc_client == NULL) {
-                /* We're shutting down; give up. */
-                /* XXX: err, or is it ok just to fall through
-                 * and rpc_restart_call? */
+        if (current_rpc_client != task->tk_client) {
+                /* We're shutting down or changing cl_cb_client; leave
+                 * it to nfsd4_process_cb_update to restart the call if
+                 * necessary. */
                 return;
         }
 
@@ -699,12 +702,6 @@ static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
         default:
                 /* Network partition? */
                 nfsd4_mark_cb_down(clp, task->tk_status);
-                if (current_rpc_client != task->tk_client) {
-                        /* queue a callback on the new connection: */
-                        atomic_inc(&dp->dl_count);
-                        run_nfsd4_cb(&dp->dl_recall);
-                        return;
-                }
         }
         if (dp->dl_retries--) {
                 rpc_delay(task, 2*HZ);