libceph: replace connection state bits with states
Use a simple set of 6 enumerated values for the socket states (CON_STATE_*)
and use those instead of the state bits. All of the con->state checks are
now under the protection of the con mutex, so this is safe. It also
simplifies many of the state checks because we can check for anything other
than the expected state instead of various bits for races we can think of.
This appears to hold up well to stress testing both with and without socket
failure injection on the server side.
Signed-off-by: Sage Weil <sage@inktank.com>
diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index a310d7f..d9c2b8f 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -117,18 +117,6 @@
#define BACKOFF 15
/*
- * ceph_connection states
- */
-#define CONNECTING 1
-#define NEGOTIATING 2
-#define CONNECTED 5
-#define STANDBY 8 /* no outgoing messages, socket closed. we keep
- * the ceph_connection around to maintain shared
- * state with the peer. */
-#define CLOSED 10 /* we've closed the connection */
-#define OPENING 13 /* open connection w/ (possibly new) peer */
-
-/*
* A single connection with another host.
*
* We maintain a queue of outgoing messages, and some session state to
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index e7320cd..563e46a 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -77,6 +77,17 @@
#define CON_SOCK_STATE_CONNECTED 3 /* -> CLOSING or -> CLOSED */
#define CON_SOCK_STATE_CLOSING 4 /* -> CLOSED */
+/*
+ * connection states
+ */
+#define CON_STATE_CLOSED 1 /* -> PREOPEN */
+#define CON_STATE_PREOPEN 2 /* -> CONNECTING, CLOSED */
+#define CON_STATE_CONNECTING 3 /* -> NEGOTIATING, CLOSED */
+#define CON_STATE_NEGOTIATING 4 /* -> OPEN, CLOSED */
+#define CON_STATE_OPEN 5 /* -> STANDBY, CLOSED */
+#define CON_STATE_STANDBY 6 /* -> PREOPEN, CLOSED */
+
+
/* static tag bytes (protocol control messages) */
static char tag_msg = CEPH_MSGR_TAG_MSG;
static char tag_ack = CEPH_MSGR_TAG_ACK;
@@ -503,11 +514,7 @@
mutex_lock(&con->mutex);
dout("con_close %p peer %s\n", con,
ceph_pr_addr(&con->peer_addr.in_addr));
- clear_bit(NEGOTIATING, &con->state);
- clear_bit(CONNECTING, &con->state);
- clear_bit(CONNECTED, &con->state);
- clear_bit(STANDBY, &con->state); /* avoid connect_seq bump */
- set_bit(CLOSED, &con->state);
+ con->state = CON_STATE_CLOSED;
clear_bit(LOSSYTX, &con->flags); /* so we retry next connect */
clear_bit(KEEPALIVE_PENDING, &con->flags);
@@ -530,8 +537,9 @@
{
mutex_lock(&con->mutex);
dout("con_open %p %s\n", con, ceph_pr_addr(&addr->in_addr));
- set_bit(OPENING, &con->state);
- WARN_ON(!test_and_clear_bit(CLOSED, &con->state));
+
+ BUG_ON(con->state != CON_STATE_CLOSED);
+ con->state = CON_STATE_PREOPEN;
con->peer_name.type = (__u8) entity_type;
con->peer_name.num = cpu_to_le64(entity_num);
@@ -571,7 +579,7 @@
INIT_LIST_HEAD(&con->out_sent);
INIT_DELAYED_WORK(&con->work, con_work);
- set_bit(CLOSED, &con->state);
+ con->state = CON_STATE_CLOSED;
}
EXPORT_SYMBOL(ceph_con_init);
@@ -809,27 +817,21 @@
if (!con->ops->get_authorizer) {
con->out_connect.authorizer_protocol = CEPH_AUTH_UNKNOWN;
con->out_connect.authorizer_len = 0;
-
return NULL;
}
/* Can't hold the mutex while getting authorizer */
-
mutex_unlock(&con->mutex);
-
auth = con->ops->get_authorizer(con, auth_proto, con->auth_retry);
-
mutex_lock(&con->mutex);
if (IS_ERR(auth))
return auth;
- if (test_bit(CLOSED, &con->state) || test_bit(OPENING, &con->flags))
+ if (con->state != CON_STATE_NEGOTIATING)
return ERR_PTR(-EAGAIN);
con->auth_reply_buf = auth->authorizer_reply_buf;
con->auth_reply_buf_len = auth->authorizer_reply_buf_len;
-
-
return auth;
}
@@ -1484,7 +1486,8 @@
static void fail_protocol(struct ceph_connection *con)
{
reset_connection(con);
- set_bit(CLOSED, &con->state); /* in case there's queued work */
+ BUG_ON(con->state != CON_STATE_NEGOTIATING);
+ con->state = CON_STATE_CLOSED;
}
static int process_connect(struct ceph_connection *con)
@@ -1558,8 +1561,7 @@
if (con->ops->peer_reset)
con->ops->peer_reset(con);
mutex_lock(&con->mutex);
- if (test_bit(CLOSED, &con->state) ||
- test_bit(OPENING, &con->state))
+ if (con->state != CON_STATE_NEGOTIATING)
return -EAGAIN;
break;
@@ -1605,8 +1607,10 @@
fail_protocol(con);
return -1;
}
- clear_bit(NEGOTIATING, &con->state);
- set_bit(CONNECTED, &con->state);
+
+ BUG_ON(con->state != CON_STATE_NEGOTIATING);
+ con->state = CON_STATE_OPEN;
+
con->peer_global_seq = le32_to_cpu(con->in_reply.global_seq);
con->connect_seq++;
con->peer_features = server_feat;
@@ -1994,8 +1998,9 @@
dout("try_write out_kvec_bytes %d\n", con->out_kvec_bytes);
/* open the socket first? */
- if (con->sock == NULL) {
- set_bit(CONNECTING, &con->state);
+ if (con->state == CON_STATE_PREOPEN) {
+ BUG_ON(con->sock);
+ con->state = CON_STATE_CONNECTING;
con_out_kvec_reset(con);
prepare_write_banner(con);
@@ -2046,8 +2051,7 @@
}
do_next:
- if (!test_bit(CONNECTING, &con->state) &&
- !test_bit(NEGOTIATING, &con->state)) {
+ if (con->state == CON_STATE_OPEN) {
/* is anything else pending? */
if (!list_empty(&con->out_queue)) {
prepare_write_message(con);
@@ -2081,29 +2085,19 @@
{
int ret = -1;
- if (!con->sock)
- return 0;
-
- if (test_bit(STANDBY, &con->state))
- return 0;
-
- dout("try_read start on %p\n", con);
-
more:
+ dout("try_read start on %p state %lu\n", con, con->state);
+ if (con->state != CON_STATE_CONNECTING &&
+ con->state != CON_STATE_NEGOTIATING &&
+ con->state != CON_STATE_OPEN)
+ return 0;
+
+ BUG_ON(!con->sock);
+
dout("try_read tag %d in_base_pos %d\n", (int)con->in_tag,
con->in_base_pos);
- /*
- * process_connect and process_message drop and re-take
- * con->mutex. make sure we handle a racing close or reopen.
- */
- if (test_bit(CLOSED, &con->state) ||
- test_bit(OPENING, &con->state)) {
- ret = -EAGAIN;
- goto out;
- }
-
- if (test_bit(CONNECTING, &con->state)) {
+ if (con->state == CON_STATE_CONNECTING) {
dout("try_read connecting\n");
ret = read_partial_banner(con);
if (ret <= 0)
@@ -2112,8 +2106,8 @@
if (ret < 0)
goto out;
- clear_bit(CONNECTING, &con->state);
- set_bit(NEGOTIATING, &con->state);
+ BUG_ON(con->state != CON_STATE_CONNECTING);
+ con->state = CON_STATE_NEGOTIATING;
/* Banner is good, exchange connection info */
ret = prepare_write_connect(con);
@@ -2125,7 +2119,7 @@
goto out;
}
- if (test_bit(NEGOTIATING, &con->state)) {
+ if (con->state == CON_STATE_NEGOTIATING) {
dout("try_read negotiating\n");
ret = read_partial_connect(con);
if (ret <= 0)
@@ -2136,6 +2130,8 @@
goto more;
}
+ BUG_ON(con->state != CON_STATE_OPEN);
+
if (con->in_base_pos < 0) {
/*
* skipping + discarding content.
@@ -2169,8 +2165,8 @@
prepare_read_ack(con);
break;
case CEPH_MSGR_TAG_CLOSE:
- clear_bit(CONNECTED, &con->state);
- set_bit(CLOSED, &con->state); /* fixme */
+ con_close_socket(con);
+ con->state = CON_STATE_CLOSED;
goto out;
default:
goto bad_tag;
@@ -2246,14 +2242,21 @@
mutex_lock(&con->mutex);
restart:
if (test_and_clear_bit(SOCK_CLOSED, &con->flags)) {
- if (test_and_clear_bit(CONNECTED, &con->state))
- con->error_msg = "socket closed";
- else if (test_and_clear_bit(NEGOTIATING, &con->state))
- con->error_msg = "negotiation failed";
- else if (test_and_clear_bit(CONNECTING, &con->state))
+ switch (con->state) {
+ case CON_STATE_CONNECTING:
con->error_msg = "connection failed";
- else
+ break;
+ case CON_STATE_NEGOTIATING:
+ con->error_msg = "negotiation failed";
+ break;
+ case CON_STATE_OPEN:
+ con->error_msg = "socket closed";
+ break;
+ default:
+ dout("unrecognized con state %d\n", (int)con->state);
con->error_msg = "unrecognized con state";
+ BUG();
+ }
goto fault;
}
@@ -2271,17 +2274,16 @@
}
}
- if (test_bit(STANDBY, &con->state)) {
+ if (con->state == CON_STATE_STANDBY) {
dout("con_work %p STANDBY\n", con);
goto done;
}
- if (test_bit(CLOSED, &con->state)) {
+ if (con->state == CON_STATE_CLOSED) {
dout("con_work %p CLOSED\n", con);
BUG_ON(con->sock);
goto done;
}
- if (test_and_clear_bit(OPENING, &con->state)) {
- /* reopen w/ new peer */
+ if (con->state == CON_STATE_PREOPEN) {
dout("con_work OPENING\n");
BUG_ON(con->sock);
}
@@ -2328,13 +2330,15 @@
dout("fault %p state %lu to peer %s\n",
con, con->state, ceph_pr_addr(&con->peer_addr.in_addr));
- if (test_bit(CLOSED, &con->state))
- goto out_unlock;
+ BUG_ON(con->state != CON_STATE_CONNECTING &&
+ con->state != CON_STATE_NEGOTIATING &&
+ con->state != CON_STATE_OPEN);
con_close_socket(con);
if (test_bit(LOSSYTX, &con->flags)) {
- dout("fault on LOSSYTX channel\n");
+ dout("fault on LOSSYTX channel, marking CLOSED\n");
+ con->state = CON_STATE_CLOSED;
goto out_unlock;
}
@@ -2355,9 +2359,10 @@
!test_bit(KEEPALIVE_PENDING, &con->flags)) {
dout("fault %p setting STANDBY clearing WRITE_PENDING\n", con);
clear_bit(WRITE_PENDING, &con->flags);
- set_bit(STANDBY, &con->state);
+ con->state = CON_STATE_STANDBY;
} else {
/* retry after a delay. */
+ con->state = CON_STATE_PREOPEN;
if (con->delay == 0)
con->delay = BASE_DELAY_INTERVAL;
else if (con->delay < MAX_DELAY_INTERVAL)
@@ -2431,8 +2436,9 @@
static void clear_standby(struct ceph_connection *con)
{
/* come back from STANDBY? */
- if (test_and_clear_bit(STANDBY, &con->state)) {
+ if (con->state == CON_STATE_STANDBY) {
dout("clear_standby %p and ++connect_seq\n", con);
+ con->state = CON_STATE_PREOPEN;
con->connect_seq++;
WARN_ON(test_bit(WRITE_PENDING, &con->flags));
WARN_ON(test_bit(KEEPALIVE_PENDING, &con->flags));
@@ -2451,7 +2457,7 @@
mutex_lock(&con->mutex);
- if (test_bit(CLOSED, &con->state)) {
+ if (con->state == CON_STATE_CLOSED) {
dout("con_send %p closed, dropping %p\n", con, msg);
ceph_msg_put(msg);
mutex_unlock(&con->mutex);