From 4e255721d1575a766ada06dc7eb03acdcd34eaaf Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 5 Jun 2017 14:30:49 +0100 Subject: rxrpc: Add service upgrade support for client connections Make it possible for a client to use AuriStor's service upgrade facility. The client does this by adding an RXRPC_UPGRADE_SERVICE control message to the first sendmsg() of a call. This takes no parameters. When recvmsg() starts returning data from the call, the service ID field in the returned msg_name will reflect the result of the upgrade attempt. If the upgrade was ignored, srx_service will match what was set in the sendmsg(); if the upgrade happened the srx_service will be altered to indicate the service the server upgraded to. Note that: (1) The choice of upgrade service is up to the server (2) Further client calls to the same server that would share a connection are blocked if an upgrade probe is in progress. (3) This should only be used to probe the service. Clients should then use the returned service ID in all subsequent communications with that server (and not set the upgrade). Note that the kernel will not retain this information should the connection expire from its cache. (4) If a server that supports upgrading is replaced by one that doesn't, whilst a connection is live, and if the replacement is running, say, OpenAFS 1.6.4 or older or an older IBM AFS, then the replacement server will not respond to packets sent to the upgraded connection. At this point, calls will time out and the server must be reprobed. Signed-off-by: David Howells --- net/rxrpc/conn_client.c | 43 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) (limited to 'net/rxrpc/conn_client.c') diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c index 3f358bf424ad..dd8bb919c15a 100644 --- a/net/rxrpc/conn_client.c +++ b/net/rxrpc/conn_client.c @@ -36,12 +36,15 @@ * * rxrpc_nr_active_client_conns is held incremented also. * - * (4) CULLED - The connection got summarily culled to try and free up + * (4) UPGRADE - As for ACTIVE, but only one call may be in progress and is + * being used to probe for service upgrade. + * + * (5) CULLED - The connection got summarily culled to try and free up * capacity. Calls currently in progress on the connection are allowed to * continue, but new calls will have to wait. There can be no waiters in * this state - the conn would have to go to the WAITING state instead. * - * (5) IDLE - The connection has no calls in progress upon it and must have + * (6) IDLE - The connection has no calls in progress upon it and must have * been exposed to the world (ie. the EXPOSED flag must be set). When it * expires, the EXPOSED flag is cleared and the connection transitions to * the INACTIVE state. @@ -184,6 +187,8 @@ rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp) atomic_set(&conn->usage, 1); if (cp->exclusive) __set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); + if (cp->upgrade) + __set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags); conn->params = *cp; conn->out_clientflag = RXRPC_CLIENT_INITIATED; @@ -300,7 +305,8 @@ static int rxrpc_get_client_conn(struct rxrpc_call *call, #define cmp(X) ((long)conn->params.X - (long)cp->X) diff = (cmp(peer) ?: cmp(key) ?: - cmp(security_level)); + cmp(security_level) ?: + cmp(upgrade)); #undef cmp if (diff < 0) { p = p->rb_left; @@ -365,7 +371,8 @@ static int rxrpc_get_client_conn(struct rxrpc_call *call, #define cmp(X) ((long)conn->params.X - (long)candidate->params.X) diff = (cmp(peer) ?: cmp(key) ?: - cmp(security_level)); + cmp(security_level) ?: + cmp(upgrade)); #undef cmp if (diff < 0) { pp = &(*pp)->rb_left; @@ -436,8 +443,13 @@ error: static void rxrpc_activate_conn(struct rxrpc_net *rxnet, struct rxrpc_connection *conn) { - trace_rxrpc_client(conn, -1, rxrpc_client_to_active); - conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE; + if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) { + trace_rxrpc_client(conn, -1, rxrpc_client_to_upgrade); + conn->cache_state = RXRPC_CONN_CLIENT_UPGRADE; + } else { + trace_rxrpc_client(conn, -1, rxrpc_client_to_active); + conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE; + } rxnet->nr_active_client_conns++; list_move_tail(&conn->cache_link, &rxnet->active_client_conns); } @@ -461,7 +473,8 @@ static void rxrpc_animate_client_conn(struct rxrpc_net *rxnet, _enter("%d,%d", conn->debug_id, conn->cache_state); - if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE) + if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE || + conn->cache_state == RXRPC_CONN_CLIENT_UPGRADE) goto out; spin_lock(&rxnet->client_conn_cache_lock); @@ -474,6 +487,7 @@ static void rxrpc_animate_client_conn(struct rxrpc_net *rxnet, switch (conn->cache_state) { case RXRPC_CONN_CLIENT_ACTIVE: + case RXRPC_CONN_CLIENT_UPGRADE: case RXRPC_CONN_CLIENT_WAITING: break; @@ -577,6 +591,9 @@ static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn) case RXRPC_CONN_CLIENT_ACTIVE: mask = RXRPC_ACTIVE_CHANS_MASK; break; + case RXRPC_CONN_CLIENT_UPGRADE: + mask = 0x01; + break; default: return; } @@ -787,6 +804,15 @@ void rxrpc_disconnect_client_call(struct rxrpc_call *call) spin_lock(&rxnet->client_conn_cache_lock); switch (conn->cache_state) { + case RXRPC_CONN_CLIENT_UPGRADE: + /* Deal with termination of a service upgrade probe. */ + if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) { + clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags); + trace_rxrpc_client(conn, channel, rxrpc_client_to_active); + conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE; + rxrpc_activate_channels_locked(conn); + } + /* fall through */ case RXRPC_CONN_CLIENT_ACTIVE: if (list_empty(&conn->waiting_calls)) { rxrpc_deactivate_one_channel(conn, channel); @@ -941,7 +967,8 @@ static void rxrpc_cull_active_client_conns(struct rxrpc_net *rxnet) ASSERT(!list_empty(&rxnet->active_client_conns)); conn = list_entry(rxnet->active_client_conns.next, struct rxrpc_connection, cache_link); - ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_ACTIVE); + ASSERTIFCMP(conn->cache_state != RXRPC_CONN_CLIENT_ACTIVE, + conn->cache_state, ==, RXRPC_CONN_CLIENT_UPGRADE); if (list_empty(&conn->waiting_calls)) { trace_rxrpc_client(conn, -1, rxrpc_client_to_culled); -- cgit v1.2.3