Propagate error through grpc_lb_policy_cancel_picks(). Also fix error

reporting (and improve control flow) in on_writable() in tcp_client_posix.c.

src/core/ext/client_config/client_channel.c

@@ -112,7 +112,8 @@ static void set_channel_connectivity_state_locked(grpc_exec_ctx *exec_ctx,
     grpc_lb_policy_cancel_picks(
         exec_ctx, chand->lb_policy,
         /* mask= */ GRPC_INITIAL_METADATA_IGNORE_CONNECTIVITY,
-        /* check= */ 0);
+        /* check= */ 0,
+        GRPC_ERROR_REF(error));
   }
   grpc_connectivity_state_set(exec_ctx, &chand->state_tracker, state, error,
                               reason);

src/core/ext/client_config/lb_policy.c

@@ -118,9 +118,10 @@ void grpc_lb_policy_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
 void grpc_lb_policy_cancel_picks(grpc_exec_ctx *exec_ctx,
                                  grpc_lb_policy *policy,
                                  uint32_t initial_metadata_flags_mask,
-                                 uint32_t initial_metadata_flags_eq) {
+                                 uint32_t initial_metadata_flags_eq,
+                                 grpc_error *error) {
   policy->vtable->cancel_picks(exec_ctx, policy, initial_metadata_flags_mask,
-                               initial_metadata_flags_eq);
+                               initial_metadata_flags_eq, error);
 }
 
 void grpc_lb_policy_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy) {

src/core/ext/client_config/lb_policy.h

@@ -68,7 +68,7 @@ struct grpc_lb_policy_vtable {
                       grpc_connected_subchannel **target, grpc_error *error);
   void (*cancel_picks)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
                        uint32_t initial_metadata_flags_mask,
-                       uint32_t initial_metadata_flags_eq);
+                       uint32_t initial_metadata_flags_eq, grpc_error *error);
 
   void (*ping_one)(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
                    grpc_closure *closure);
@@ -148,7 +148,8 @@ void grpc_lb_policy_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
 void grpc_lb_policy_cancel_picks(grpc_exec_ctx *exec_ctx,
                                  grpc_lb_policy *policy,
                                  uint32_t initial_metadata_flags_mask,
-                                 uint32_t initial_metadata_flags_eq);
+                                 uint32_t initial_metadata_flags_eq,
+                                 grpc_error *error);
 
 /** Try to enter a READY connectivity state */
 void grpc_lb_policy_exit_idle(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy);

src/core/ext/client_config/subchannel.c

@@ -635,7 +635,9 @@ static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *arg,
     c->have_alarm = 1;
     grpc_connectivity_state_set(
         exec_ctx, &c->state_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
-        GRPC_ERROR_CREATE_REFERENCING("Connect Failed", &error, 1),
+        grpc_error_set_int(
+            GRPC_ERROR_CREATE_REFERENCING("Connect Failed", &error, 1),
+            GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE),
         "connect_failed");
     gpr_timespec time_til_next = gpr_time_sub(c->next_attempt, now);
     const char *errmsg = grpc_error_string(error);

src/core/ext/lb_policy/grpclb/grpclb.c

@@ -562,7 +562,8 @@ static void glb_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
 static grpc_call *lb_client_data_get_call(struct lb_client_data *lb_client);
 static void glb_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                              uint32_t initial_metadata_flags_mask,
-                             uint32_t initial_metadata_flags_eq) {
+                             uint32_t initial_metadata_flags_eq,
+                             grpc_error *error) {
   glb_lb_policy *glb_policy = (glb_lb_policy *)pol;
   gpr_mu_lock(&glb_policy->mu);
   if (glb_policy->lb_client != NULL) {
@@ -578,7 +579,8 @@ static void glb_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
       grpc_polling_entity_del_from_pollset_set(
           exec_ctx, pp->pollent, glb_policy->base.interested_parties);
       grpc_exec_ctx_sched(exec_ctx, &pp->wrapped_on_complete,
-                          GRPC_ERROR_CANCELLED, NULL);
+                          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled",
+                                                        &error, 1), NULL);
       gpr_free(pp);
     } else {
       pp->next = glb_policy->pending_picks;
@@ -587,6 +589,7 @@ static void glb_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pp = next;
   }
   gpr_mu_unlock(&glb_policy->mu);
+  GRPC_ERROR_UNREF(error);
 }
 
 static void query_for_backends(grpc_exec_ctx *exec_ctx,

src/core/ext/lb_policy/pick_first/pick_first.c

@@ -157,7 +157,8 @@ static void pf_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
 
 static void pf_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                             uint32_t initial_metadata_flags_mask,
-                            uint32_t initial_metadata_flags_eq) {
+                            uint32_t initial_metadata_flags_eq,
+                            grpc_error *error) {
   pick_first_lb_policy *p = (pick_first_lb_policy *)pol;
   pending_pick *pp;
   gpr_mu_lock(&p->mu);
@@ -170,7 +171,8 @@ static void pf_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
       grpc_polling_entity_del_from_pollset_set(exec_ctx, pp->pollent,
                                                p->base.interested_parties);
       grpc_exec_ctx_sched(exec_ctx, pp->on_complete,
-                          GRPC_ERROR_CREATE("Pick Cancelled"), NULL);
+                          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled",
+                                                        &error, 1), NULL);
       gpr_free(pp);
     } else {
       pp->next = p->pending_picks;
@@ -179,6 +181,7 @@ static void pf_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pp = next;
   }
   gpr_mu_unlock(&p->mu);
+  GRPC_ERROR_UNREF(error);
 }
 
 static void start_picking(grpc_exec_ctx *exec_ctx, pick_first_lb_policy *p) {

src/core/ext/lb_policy/round_robin/round_robin.c

@@ -310,7 +310,8 @@ static void rr_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
 
 static void rr_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                             uint32_t initial_metadata_flags_mask,
-                            uint32_t initial_metadata_flags_eq) {
+                            uint32_t initial_metadata_flags_eq,
+                            grpc_error *error) {
   round_robin_lb_policy *p = (round_robin_lb_policy *)pol;
   pending_pick *pp;
   gpr_mu_lock(&p->mu);
@@ -323,8 +324,9 @@ static void rr_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
       grpc_polling_entity_del_from_pollset_set(exec_ctx, pp->pollent,
                                                p->base.interested_parties);
       *pp->target = NULL;
-      grpc_exec_ctx_sched(exec_ctx, pp->on_complete, GRPC_ERROR_CANCELLED,
+      grpc_exec_ctx_sched(exec_ctx, pp->on_complete,
-                          NULL);
+                          GRPC_ERROR_CREATE_REFERENCING("Pick cancelled",
+                                                        &error, 1), NULL);
       gpr_free(pp);
     } else {
       pp->next = p->pending_picks;
@@ -333,6 +335,7 @@ static void rr_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pp = next;
   }
   gpr_mu_unlock(&p->mu);
+  GRPC_ERROR_UNREF(error);
 }
 
 static void start_picking(grpc_exec_ctx *exec_ctx, round_robin_lb_policy *p) {

src/core/lib/iomgr/tcp_client_posix.c

@@ -146,61 +146,57 @@ static void on_writable(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
   grpc_timer_cancel(exec_ctx, &ac->alarm);
 
   gpr_mu_lock(&ac->mu);
-  if (error == GRPC_ERROR_NONE) {
+  if (error != GRPC_ERROR_NONE) {
-    do {
-      so_error_size = sizeof(so_error);
-      err = getsockopt(grpc_fd_wrapped_fd(fd), SOL_SOCKET, SO_ERROR, &so_error,
-                       &so_error_size);
-    } while (err < 0 && errno == EINTR);
-    if (err < 0) {
-      error = GRPC_OS_ERROR(errno, "getsockopt");
-      goto finish;
-    } else if (so_error != 0) {
-      if (so_error == ENOBUFS) {
-        /* We will get one of these errors if we have run out of
-           memory in the kernel for the data structures allocated
-           when you connect a socket.  If this happens it is very
-           likely that if we wait a little bit then try again the
-           connection will work (since other programs or this
-           program will close their network connections and free up
-           memory).  This does _not_ indicate that there is anything
-           wrong with the server we are connecting to, this is a
-           local problem.
-
-           If you are looking at this code, then chances are that
-           your program or another program on the same computer
-           opened too many network connections.  The "easy" fix:
-           don't do that! */
-        gpr_log(GPR_ERROR, "kernel out of buffers");
-        gpr_mu_unlock(&ac->mu);
-        grpc_fd_notify_on_write(exec_ctx, fd, &ac->write_closure);
-        return;
-      } else {
-        switch (so_error) {
-          case ECONNREFUSED:
-            error = grpc_error_set_int(error, GRPC_ERROR_INT_ERRNO, errno);
-            error = grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR,
-                                       "Connection refused");
-            break;
-          default:
-            error = GRPC_OS_ERROR(errno, "getsockopt(SO_ERROR)");
-            break;
-        }
-        goto finish;
-      }
-    } else {
-      grpc_pollset_set_del_fd(exec_ctx, ac->interested_parties, fd);
-      *ep = grpc_tcp_create(fd, GRPC_TCP_DEFAULT_READ_SLICE_SIZE, ac->addr_str);
-      fd = NULL;
-      goto finish;
-    }
-  } else {
     error =
         grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, "Timeout occurred");
     goto finish;
   }
 
-  GPR_UNREACHABLE_CODE(return );
+  do {
+    so_error_size = sizeof(so_error);
+    err = getsockopt(grpc_fd_wrapped_fd(fd), SOL_SOCKET, SO_ERROR, &so_error,
+                     &so_error_size);
+  } while (err < 0 && errno == EINTR);
+  if (err < 0) {
+    error = GRPC_OS_ERROR(errno, "getsockopt");
+    goto finish;
+  }
+
+  switch (so_error) {
+    case 0:
+      grpc_pollset_set_del_fd(exec_ctx, ac->interested_parties, fd);
+      *ep = grpc_tcp_create(fd, GRPC_TCP_DEFAULT_READ_SLICE_SIZE, ac->addr_str);
+      fd = NULL;
+      break;
+    case ENOBUFS:
+      /* We will get one of these errors if we have run out of
+         memory in the kernel for the data structures allocated
+         when you connect a socket.  If this happens it is very
+         likely that if we wait a little bit then try again the
+         connection will work (since other programs or this
+         program will close their network connections and free up
+         memory).  This does _not_ indicate that there is anything
+         wrong with the server we are connecting to, this is a
+         local problem.
+
+         If you are looking at this code, then chances are that
+         your program or another program on the same computer
+         opened too many network connections.  The "easy" fix:
+         don't do that! */
+      gpr_log(GPR_ERROR, "kernel out of buffers");
+      gpr_mu_unlock(&ac->mu);
+      grpc_fd_notify_on_write(exec_ctx, fd, &ac->write_closure);
+      return;
+    case ECONNREFUSED:
+      /* This error shouldn't happen for anything other than connect(). */
+      error = GRPC_OS_ERROR(so_error, "connect");
+      break;
+    default:
+      /* We don't really know which syscall triggered the problem here,
+         so punt by reporting getsockopt(). */
+      error = GRPC_OS_ERROR(so_error, "getsockopt(SO_ERROR)");
+      break;
+  }
 
 finish:
   if (fd != NULL) {