1 files changed, 84 insertions, 43 deletions

diff --git a/fs/afs/vl_rotate.c b/fs/afs/vl_rotate.c
index e2dc54082a..d8f79f6ada 100644
--- a/fs/afs/vl_rotate.c
+++ b/fs/afs/vl_rotate.c
@@ -17,6 +17,8 @@
 bool afs_begin_vlserver_operation(struct afs_vl_cursor *vc, struct afs_cell *cell,
 				  struct key *key)
 {
+	static atomic_t debug_ids;
+
 	memset(vc, 0, sizeof(*vc));
 	vc->cell = cell;
 	vc->key = key;
@@ -29,6 +31,7 @@ bool afs_begin_vlserver_operation(struct afs_vl_cursor *vc, struct afs_cell *cel
 		return false;
 	}
 
+	vc->debug_id = atomic_inc_return(&debug_ids);
 	return true;
 }
 
@@ -78,8 +81,8 @@ static bool afs_start_vl_iteration(struct afs_vl_cursor *vc)
 	if (!vc->server_list->nr_servers)
 		return false;
 
-	vc->untried = (1UL << vc->server_list->nr_servers) - 1;
-	vc->index = -1;
+	vc->untried_servers = (1UL << vc->server_list->nr_servers) - 1;
+	vc->server_index = -1;
 	return true;
 }
 
@@ -89,17 +92,18 @@ static bool afs_start_vl_iteration(struct afs_vl_cursor *vc)
  */
 bool afs_select_vlserver(struct afs_vl_cursor *vc)
 {
-	struct afs_addr_list *alist;
+	struct afs_addr_list *alist = vc->alist;
 	struct afs_vlserver *vlserver;
+	unsigned long set, failed;
 	unsigned int rtt;
 	s32 abort_code = vc->call_abort_code;
 	int error = vc->call_error, i;
 
 	vc->nr_iterations++;
 
-	_enter("%lx[%d],%lx[%d],%d,%d",
-	       vc->untried, vc->index,
-	       vc->ac.tried, vc->ac.index,
+	_enter("VC=%x+%x,%d{%lx},%d{%lx},%d,%d",
+	       vc->debug_id, vc->nr_iterations, vc->server_index, vc->untried_servers,
+	       vc->addr_index, vc->addr_tried,
 	       error, abort_code);
 
 	if (vc->flags & AFS_VL_CURSOR_STOP) {
@@ -110,6 +114,8 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
 	if (vc->nr_iterations == 0)
 		goto start;
 
+	WRITE_ONCE(alist->addrs[vc->addr_index].last_error, error);
+
 	/* Evaluate the result of the previous operation, if there was one. */
 	switch (error) {
 	default:
@@ -131,7 +137,7 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
 			/* The server went weird. */
 			afs_prioritise_error(&vc->cumul_error, -EREMOTEIO, abort_code);
 			//write_lock(&vc->cell->vl_servers_lock);
-			//vc->server_list->weird_mask |= 1 << vc->index;
+			//vc->server_list->weird_mask |= 1 << vc->server_index;
 			//write_unlock(&vc->cell->vl_servers_lock);
 			goto next_server;
 
@@ -165,7 +171,13 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
 
 restart_from_beginning:
 	_debug("restart");
-	afs_end_cursor(&vc->ac);
+	if (vc->call_responded &&
+	    vc->addr_index != vc->alist->preferred &&
+	    test_bit(alist->preferred, &vc->addr_tried))
+		WRITE_ONCE(alist->preferred, vc->addr_index);
+	afs_put_addrlist(alist, afs_alist_trace_put_vlrotate_restart);
+	alist = vc->alist = NULL;
+
 	afs_put_vlserverlist(vc->cell->net, vc->server_list);
 	vc->server_list = NULL;
 	if (vc->flags & AFS_VL_CURSOR_RETRIED)
@@ -173,6 +185,7 @@ restart_from_beginning:
 	vc->flags |= AFS_VL_CURSOR_RETRIED;
 start:
 	_debug("start");
+	ASSERTCMP(alist, ==, NULL);
 
 	if (!afs_start_vl_iteration(vc))
 		goto failed;
@@ -184,46 +197,46 @@ start:
 	}
 
 pick_server:
-	_debug("pick [%lx]", vc->untried);
+	_debug("pick [%lx]", vc->untried_servers);
+	ASSERTCMP(alist, ==, NULL);
 
-	error = afs_wait_for_vl_probes(vc->server_list, vc->untried);
+	error = afs_wait_for_vl_probes(vc->server_list, vc->untried_servers);
 	if (error < 0) {
 		afs_prioritise_error(&vc->cumul_error, error, 0);
 		goto failed;
 	}
 
 	/* Pick the untried server with the lowest RTT. */
-	vc->index = vc->server_list->preferred;
-	if (test_bit(vc->index, &vc->untried))
+	vc->server_index = vc->server_list->preferred;
+	if (test_bit(vc->server_index, &vc->untried_servers))
 		goto selected_server;
 
-	vc->index = -1;
+	vc->server_index = -1;
 	rtt = UINT_MAX;
 	for (i = 0; i < vc->server_list->nr_servers; i++) {
 		struct afs_vlserver *s = vc->server_list->servers[i].server;
 
-		if (!test_bit(i, &vc->untried) ||
+		if (!test_bit(i, &vc->untried_servers) ||
 		    !test_bit(AFS_VLSERVER_FL_RESPONDING, &s->flags))
 			continue;
-		if (s->probe.rtt < rtt) {
-			vc->index = i;
+		if (s->probe.rtt <= rtt) {
+			vc->server_index = i;
 			rtt = s->probe.rtt;
 		}
 	}
 
-	if (vc->index == -1)
+	if (vc->server_index == -1)
 		goto no_more_servers;
 
 selected_server:
-	_debug("use %d", vc->index);
-	__clear_bit(vc->index, &vc->untried);
+	_debug("use %d", vc->server_index);
+	__clear_bit(vc->server_index, &vc->untried_servers);
 
 	/* We're starting on a different vlserver from the list.  We need to
 	 * check it, find its address list and probe its capabilities before we
 	 * use it.
 	 */
-	ASSERTCMP(vc->ac.alist, ==, NULL);
-	vlserver = vc->server_list->servers[vc->index].server;
+	vlserver = vc->server_list->servers[vc->server_index].server;
 	vc->server = vlserver;
 
 	_debug("USING VLSERVER: %s", vlserver->name);
@@ -231,35 +244,48 @@ selected_server:
 	read_lock(&vlserver->lock);
 	alist = rcu_dereference_protected(vlserver->addresses,
 					  lockdep_is_held(&vlserver->lock));
-	afs_get_addrlist(alist);
+	vc->alist = afs_get_addrlist(alist, afs_alist_trace_get_vlrotate_set);
 	read_unlock(&vlserver->lock);
 
-	memset(&vc->ac, 0, sizeof(vc->ac));
-
-	if (!vc->ac.alist)
-		vc->ac.alist = alist;
-	else
-		afs_put_addrlist(alist);
-
-	vc->ac.index = -1;
+	vc->addr_tried = 0;
+	vc->addr_index = -1;
 
 iterate_address:
-	ASSERT(vc->ac.alist);
 	/* Iterate over the current server's address list to try and find an
 	 * address on which it will respond to us.
 	 */
-	if (!afs_iterate_addresses(&vc->ac))
+	set = READ_ONCE(alist->responded);
+	failed = READ_ONCE(alist->probe_failed);
+	vc->addr_index = READ_ONCE(alist->preferred);
+
+	_debug("%lx-%lx-%lx,%d", set, failed, vc->addr_tried, vc->addr_index);
+
+	set &= ~(failed | vc->addr_tried);
+
+	if (!set)
 		goto next_server;
 
-	_debug("VL address %d/%d", vc->ac.index, vc->ac.alist->nr_addrs);
+	if (!test_bit(vc->addr_index, &set))
+		vc->addr_index = __ffs(set);
+
+	set_bit(vc->addr_index, &vc->addr_tried);
+	vc->alist = alist;
+
+	_debug("VL address %d/%d", vc->addr_index, alist->nr_addrs);
 
 	vc->call_responded = false;
-	_leave(" = t %pISpc", rxrpc_kernel_remote_addr(vc->ac.alist->addrs[vc->ac.index].peer));
+	_leave(" = t %pISpc", rxrpc_kernel_remote_addr(alist->addrs[vc->addr_index].peer));
 	return true;
 
 next_server:
 	_debug("next");
-	afs_end_cursor(&vc->ac);
+	ASSERT(alist);
+	if (vc->call_responded &&
+	    vc->addr_index != alist->preferred &&
+	    test_bit(alist->preferred, &vc->addr_tried))
+		WRITE_ONCE(alist->preferred, vc->addr_index);
+	afs_put_addrlist(alist, afs_alist_trace_put_vlrotate_next);
+	alist = vc->alist = NULL;
 	goto pick_server;
 
 no_more_servers:
@@ -279,8 +305,15 @@ no_more_servers:
 	}
 
 failed:
+	if (alist) {
+		if (vc->call_responded &&
+		    vc->addr_index != alist->preferred &&
+		    test_bit(alist->preferred, &vc->addr_tried))
+			WRITE_ONCE(alist->preferred, vc->addr_index);
+		afs_put_addrlist(alist, afs_alist_trace_put_vlrotate_fail);
+		alist = vc->alist = NULL;
+	}
 	vc->flags |= AFS_VL_CURSOR_STOP;
-	afs_end_cursor(&vc->ac);
 	_leave(" = f [failed %d]", vc->cumul_error.error);
 	return false;
 }
@@ -304,8 +337,8 @@ static void afs_vl_dump_edestaddrreq(const struct afs_vl_cursor *vc)
 	pr_notice("DNS: src=%u st=%u lc=%x\n",
 		  cell->dns_source, cell->dns_status, cell->dns_lookup_count);
 	pr_notice("VC: ut=%lx ix=%u ni=%hu fl=%hx err=%hd\n",
-		  vc->untried, vc->index, vc->nr_iterations, vc->flags,
-		  vc->cumul_error.error);
+		  vc->untried_servers, vc->server_index, vc->nr_iterations,
+		  vc->flags, vc->cumul_error.error);
 	pr_notice("VC: call  er=%d ac=%d r=%u\n",
 		  vc->call_error, vc->call_abort_code, vc->call_responded);
 
@@ -324,15 +357,14 @@ static void afs_vl_dump_edestaddrreq(const struct afs_vl_cursor *vc)
 					  a->nr_ipv4, a->nr_addrs, a->max_addrs,
 					  a->preferred);
 				pr_notice("VC:  - R=%lx F=%lx\n",
-					  a->responded, a->failed);
-				if (a == vc->ac.alist)
+					  a->responded, a->probe_failed);
+				if (a == vc->alist)
 					pr_notice("VC:  - current\n");
 			}
 		}
 	}
 
-	pr_notice("AC: t=%lx ax=%u ni=%u\n",
-		  vc->ac.tried, vc->ac.index, vc->ac.nr_iterations);
+	pr_notice("AC: t=%lx ax=%u\n", vc->addr_tried, vc->addr_index);
 	rcu_read_unlock();
 }
 
@@ -343,6 +375,8 @@ int afs_end_vlserver_operation(struct afs_vl_cursor *vc)
 {
 	struct afs_net *net = vc->cell->net;
 
+	_enter("VC=%x+%x", vc->debug_id, vc->nr_iterations);
+
 	switch (vc->cumul_error.error) {
 	case -EDESTADDRREQ:
 	case -EADDRNOTAVAIL:
@@ -352,7 +386,14 @@ int afs_end_vlserver_operation(struct afs_vl_cursor *vc)
 		break;
 	}
 
-	afs_end_cursor(&vc->ac);
+	if (vc->alist) {
+		if (vc->call_responded &&
+		    vc->addr_index != vc->alist->preferred &&
+		    test_bit(vc->alist->preferred, &vc->addr_tried))
+			WRITE_ONCE(vc->alist->preferred, vc->addr_index);
+		afs_put_addrlist(vc->alist, afs_alist_trace_put_vlrotate_end);
+		vc->alist = NULL;
+	}
 	afs_put_vlserverlist(net, vc->server_list);
 	return vc->cumul_error.error;
 }