libceph: clean up con flags
[firefly-linux-kernel-4.4.55.git] / net / ceph / messenger.c
index 23073cff648111c2a279488d77940c8d48b4b782..b872db5c498941020c05c6c77a9729b70cace120 100644 (file)
  * the sender.
  */
 
-/* State values for ceph_connection->sock_state; NEW is assumed to be 0 */
+/*
+ * We track the state of the socket on a given connection using
+ * values defined below.  The transition to a new socket state is
+ * handled by a function which verifies we aren't coming from an
+ * unexpected state.
+ *
+ *      --------
+ *      | NEW* |  transient initial state
+ *      --------
+ *          | con_sock_state_init()
+ *          v
+ *      ----------
+ *      | CLOSED |  initialized, but no socket (and no
+ *      ----------  TCP connection)
+ *       ^      \
+ *       |       \ con_sock_state_connecting()
+ *       |        ----------------------
+ *       |                              \
+ *       + con_sock_state_closed()       \
+ *       |+---------------------------    \
+ *       | \                          \    \
+ *       |  -----------                \    \
+ *       |  | CLOSING |  socket event;  \    \
+ *       |  -----------  await close     \    \
+ *       |       ^                        \   |
+ *       |       |                         \  |
+ *       |       + con_sock_state_closing() \ |
+ *       |      / \                         | |
+ *       |     /   ---------------          | |
+ *       |    /                   \         v v
+ *       |   /                    --------------
+ *       |  /    -----------------| CONNECTING |  socket created, TCP
+ *       |  |   /                 --------------  connect initiated
+ *       |  |   | con_sock_state_connected()
+ *       |  |   v
+ *      -------------
+ *      | CONNECTED |  TCP connection established
+ *      -------------
+ *
+ * State values for ceph_connection->sock_state; NEW is assumed to be 0.
+ */
 
 #define CON_SOCK_STATE_NEW             0       /* -> CLOSED */
 #define CON_SOCK_STATE_CLOSED          1       /* -> CONNECTING */
 #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 */
+
+/*
+ * ceph_connection flag bits
+ */
+#define CON_FLAG_LOSSYTX           0  /* we can close channel or drop
+                                      * messages on errors */
+#define CON_FLAG_KEEPALIVE_PENDING 1  /* we need to send a keepalive */
+#define CON_FLAG_WRITE_PENDING    2  /* we have data ready to send */
+#define CON_FLAG_SOCK_CLOSED      3  /* socket state changed to closed */
+#define CON_FLAG_BACKOFF           4  /* need to retry queuing delayed work */
+
 /* static tag bytes (protocol control messages) */
 static char tag_msg = CEPH_MSGR_TAG_MSG;
 static char tag_ack = CEPH_MSGR_TAG_ACK;
@@ -201,7 +261,8 @@ static void con_sock_state_closed(struct ceph_connection *con)
 
        old_state = atomic_xchg(&con->sock_state, CON_SOCK_STATE_CLOSED);
        if (WARN_ON(old_state != CON_SOCK_STATE_CONNECTED &&
-                       old_state != CON_SOCK_STATE_CLOSING))
+                   old_state != CON_SOCK_STATE_CLOSING &&
+                   old_state != CON_SOCK_STATE_CONNECTING))
                printk("%s: unexpected old state %d\n", __func__, old_state);
 }
 
@@ -213,6 +274,9 @@ static void con_sock_state_closed(struct ceph_connection *con)
 static void ceph_sock_data_ready(struct sock *sk, int count_unused)
 {
        struct ceph_connection *con = sk->sk_user_data;
+       if (atomic_read(&con->msgr->stopping)) {
+               return;
+       }
 
        if (sk->sk_state != TCP_CLOSE_WAIT) {
                dout("%s on %p state = %lu, queueing work\n", __func__,
@@ -233,7 +297,7 @@ static void ceph_sock_write_space(struct sock *sk)
         * buffer. See net/ipv4/tcp_input.c:tcp_check_space()
         * and net/core/stream.c:sk_stream_write_space().
         */
-       if (test_bit(WRITE_PENDING, &con->flags)) {
+       if (test_bit(CON_FLAG_WRITE_PENDING, &con->flags)) {
                if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
                        dout("%s %p queueing write work\n", __func__, con);
                        clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
@@ -252,22 +316,14 @@ static void ceph_sock_state_change(struct sock *sk)
        dout("%s %p state = %lu sk_state = %u\n", __func__,
             con, con->state, sk->sk_state);
 
-       if (test_bit(CLOSED, &con->state))
-               return;
-
        switch (sk->sk_state) {
        case TCP_CLOSE:
                dout("%s TCP_CLOSE\n", __func__);
        case TCP_CLOSE_WAIT:
                dout("%s TCP_CLOSE_WAIT\n", __func__);
                con_sock_state_closing(con);
-               if (test_and_set_bit(SOCK_CLOSED, &con->flags) == 0) {
-                       if (test_bit(CONNECTING, &con->state))
-                               con->error_msg = "connection failed";
-                       else
-                               con->error_msg = "socket closed";
-                       queue_con(con);
-               }
+               set_bit(CON_FLAG_SOCK_CLOSED, &con->flags);
+               queue_con(con);
                break;
        case TCP_ESTABLISHED:
                dout("%s TCP_ESTABLISHED\n", __func__);
@@ -397,11 +453,17 @@ static int con_close_socket(struct ceph_connection *con)
        dout("con_close_socket on %p sock %p\n", con, con->sock);
        if (!con->sock)
                return 0;
-       set_bit(SOCK_CLOSED, &con->state);
        rc = con->sock->ops->shutdown(con->sock, SHUT_RDWR);
        sock_release(con->sock);
        con->sock = NULL;
-       clear_bit(SOCK_CLOSED, &con->state);
+
+       /*
+        * Forcibly clear the SOCK_CLOSED flag.  It gets set
+        * independent of the connection mutex, and we could have
+        * received a socket close event before we had the chance to
+        * shut the socket down.
+        */
+       clear_bit(CON_FLAG_SOCK_CLOSED, &con->flags);
        con_sock_state_closed(con);
        return rc;
 }
@@ -414,7 +476,7 @@ static void ceph_msg_remove(struct ceph_msg *msg)
 {
        list_del_init(&msg->list_head);
        BUG_ON(msg->con == NULL);
-       ceph_con_put(msg->con);
+       msg->con->ops->put(msg->con);
        msg->con = NULL;
 
        ceph_msg_put(msg);
@@ -440,7 +502,7 @@ static void reset_connection(struct ceph_connection *con)
                con->in_msg->con = NULL;
                ceph_msg_put(con->in_msg);
                con->in_msg = NULL;
-               ceph_con_put(con);
+               con->ops->put(con);
        }
 
        con->connect_seq = 0;
@@ -458,36 +520,42 @@ static void reset_connection(struct ceph_connection *con)
  */
 void ceph_con_close(struct ceph_connection *con)
 {
+       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(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);
-       clear_bit(WRITE_PENDING, &con->flags);
+       clear_bit(CON_FLAG_LOSSYTX, &con->flags); /* so we retry next connect */
+       clear_bit(CON_FLAG_KEEPALIVE_PENDING, &con->flags);
+       clear_bit(CON_FLAG_WRITE_PENDING, &con->flags);
 
-       mutex_lock(&con->mutex);
        reset_connection(con);
        con->peer_global_seq = 0;
        cancel_delayed_work(&con->work);
+       con_close_socket(con);
        mutex_unlock(&con->mutex);
-       queue_con(con);
 }
 EXPORT_SYMBOL(ceph_con_close);
 
 /*
  * Reopen a closed connection, with a new peer address.
  */
-void ceph_con_open(struct ceph_connection *con, struct ceph_entity_addr *addr)
+void ceph_con_open(struct ceph_connection *con,
+                  __u8 entity_type, __u64 entity_num,
+                  struct ceph_entity_addr *addr)
 {
+       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);
 
        memcpy(&con->peer_addr, addr, sizeof(*addr));
        con->delay = 0;      /* reset backoff memory */
+       mutex_unlock(&con->mutex);
        queue_con(con);
 }
 EXPORT_SYMBOL(ceph_con_open);
@@ -500,55 +568,27 @@ bool ceph_con_opened(struct ceph_connection *con)
        return con->connect_seq > 0;
 }
 
-/*
- * generic get/put
- */
-struct ceph_connection *ceph_con_get(struct ceph_connection *con)
-{
-       int nref = __atomic_add_unless(&con->nref, 1, 0);
-
-       dout("con_get %p nref = %d -> %d\n", con, nref, nref + 1);
-
-       return nref ? con : NULL;
-}
-
-void ceph_con_put(struct ceph_connection *con)
-{
-       int nref = atomic_dec_return(&con->nref);
-
-       BUG_ON(nref < 0);
-       if (nref == 0) {
-               BUG_ON(con->sock);
-               kfree(con);
-       }
-       dout("con_put %p nref = %d -> %d\n", con, nref + 1, nref);
-}
-
 /*
  * initialize a new connection.
  */
 void ceph_con_init(struct ceph_connection *con, void *private,
        const struct ceph_connection_operations *ops,
-       struct ceph_messenger *msgr, __u8 entity_type, __u64 entity_num)
+       struct ceph_messenger *msgr)
 {
        dout("con_init %p\n", con);
        memset(con, 0, sizeof(*con));
        con->private = private;
        con->ops = ops;
-       atomic_set(&con->nref, 1);
        con->msgr = msgr;
 
        con_sock_state_init(con);
 
-       con->peer_name.type = (__u8) entity_type;
-       con->peer_name.num = cpu_to_le64(entity_num);
-
        mutex_init(&con->mutex);
        INIT_LIST_HEAD(&con->out_queue);
        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);
 
@@ -590,6 +630,53 @@ static void con_out_kvec_add(struct ceph_connection *con,
        con->out_kvec_bytes += size;
 }
 
+#ifdef CONFIG_BLOCK
+static void init_bio_iter(struct bio *bio, struct bio **iter, int *seg)
+{
+       if (!bio) {
+               *iter = NULL;
+               *seg = 0;
+               return;
+       }
+       *iter = bio;
+       *seg = bio->bi_idx;
+}
+
+static void iter_bio_next(struct bio **bio_iter, int *seg)
+{
+       if (*bio_iter == NULL)
+               return;
+
+       BUG_ON(*seg >= (*bio_iter)->bi_vcnt);
+
+       (*seg)++;
+       if (*seg == (*bio_iter)->bi_vcnt)
+               init_bio_iter((*bio_iter)->bi_next, bio_iter, seg);
+}
+#endif
+
+static void prepare_write_message_data(struct ceph_connection *con)
+{
+       struct ceph_msg *msg = con->out_msg;
+
+       BUG_ON(!msg);
+       BUG_ON(!msg->hdr.data_len);
+
+       /* initialize page iterator */
+       con->out_msg_pos.page = 0;
+       if (msg->pages)
+               con->out_msg_pos.page_pos = msg->page_alignment;
+       else
+               con->out_msg_pos.page_pos = 0;
+#ifdef CONFIG_BLOCK
+       if (msg->bio)
+               init_bio_iter(msg->bio, &msg->bio_iter, &msg->bio_seg);
+#endif
+       con->out_msg_pos.data_pos = 0;
+       con->out_msg_pos.did_page_crc = false;
+       con->out_more = 1;  /* data + footer will follow */
+}
+
 /*
  * Prepare footer for currently outgoing message, and finish things
  * off.  Assumes out_kvec* are already valid.. we just add on to the end.
@@ -599,6 +686,8 @@ static void prepare_write_message_footer(struct ceph_connection *con)
        struct ceph_msg *m = con->out_msg;
        int v = con->out_kvec_left;
 
+       m->footer.flags |= CEPH_MSG_FOOTER_COMPLETE;
+
        dout("prepare_write_message_footer %p\n", con);
        con->out_kvec_is_msg = true;
        con->out_kvec[v].iov_base = &m->footer;
@@ -648,10 +737,6 @@ static void prepare_write_message(struct ceph_connection *con)
                m->hdr.seq = cpu_to_le64(++con->out_seq);
                m->needs_out_seq = false;
        }
-#ifdef CONFIG_BLOCK
-       else
-               m->bio_iter = NULL;
-#endif
 
        dout("prepare_write_message %p seq %lld type %d len %d+%d+%d %d pgs\n",
             m, con->out_seq, le16_to_cpu(m->hdr.type),
@@ -672,7 +757,7 @@ static void prepare_write_message(struct ceph_connection *con)
        /* fill in crc (except data pages), footer */
        crc = crc32c(0, &m->hdr, offsetof(struct ceph_msg_header, crc));
        con->out_msg->hdr.crc = cpu_to_le32(crc);
-       con->out_msg->footer.flags = CEPH_MSG_FOOTER_COMPLETE;
+       con->out_msg->footer.flags = 0;
 
        crc = crc32c(0, m->front.iov_base, m->front.iov_len);
        con->out_msg->footer.front_crc = cpu_to_le32(crc);
@@ -682,28 +767,19 @@ static void prepare_write_message(struct ceph_connection *con)
                con->out_msg->footer.middle_crc = cpu_to_le32(crc);
        } else
                con->out_msg->footer.middle_crc = 0;
-       con->out_msg->footer.data_crc = 0;
-       dout("prepare_write_message front_crc %u data_crc %u\n",
+       dout("%s front_crc %u middle_crc %u\n", __func__,
             le32_to_cpu(con->out_msg->footer.front_crc),
             le32_to_cpu(con->out_msg->footer.middle_crc));
 
        /* is there a data payload? */
-       if (le32_to_cpu(m->hdr.data_len) > 0) {
-               /* initialize page iterator */
-               con->out_msg_pos.page = 0;
-               if (m->pages)
-                       con->out_msg_pos.page_pos = m->page_alignment;
-               else
-                       con->out_msg_pos.page_pos = 0;
-               con->out_msg_pos.data_pos = 0;
-               con->out_msg_pos.did_page_crc = false;
-               con->out_more = 1;  /* data + footer will follow */
-       } else {
+       con->out_msg->footer.data_crc = 0;
+       if (m->hdr.data_len)
+               prepare_write_message_data(con);
+       else
                /* no, queue up footer too and be done */
                prepare_write_message_footer(con);
-       }
 
-       set_bit(WRITE_PENDING, &con->flags);
+       set_bit(CON_FLAG_WRITE_PENDING, &con->flags);
 }
 
 /*
@@ -724,7 +800,7 @@ static void prepare_write_ack(struct ceph_connection *con)
                                &con->out_temp_ack);
 
        con->out_more = 1;  /* more will follow.. eventually.. */
-       set_bit(WRITE_PENDING, &con->flags);
+       set_bit(CON_FLAG_WRITE_PENDING, &con->flags);
 }
 
 /*
@@ -735,7 +811,7 @@ static void prepare_write_keepalive(struct ceph_connection *con)
        dout("prepare_write_keepalive %p\n", con);
        con_out_kvec_reset(con);
        con_out_kvec_add(con, sizeof (tag_keepalive), &tag_keepalive);
-       set_bit(WRITE_PENDING, &con->flags);
+       set_bit(CON_FLAG_WRITE_PENDING, &con->flags);
 }
 
 /*
@@ -750,27 +826,21 @@ static struct ceph_auth_handshake *get_connect_authorizer(struct ceph_connection
        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;
 }
 
@@ -784,7 +854,7 @@ static void prepare_write_banner(struct ceph_connection *con)
                                        &con->msgr->my_enc_addr);
 
        con->out_more = 0;
-       set_bit(WRITE_PENDING, &con->flags);
+       set_bit(CON_FLAG_WRITE_PENDING, &con->flags);
 }
 
 static int prepare_write_connect(struct ceph_connection *con)
@@ -827,6 +897,7 @@ static int prepare_write_connect(struct ceph_connection *con)
        con->out_connect.authorizer_len = auth ?
                cpu_to_le32(auth->authorizer_buf_len) : 0;
 
+       con_out_kvec_reset(con);
        con_out_kvec_add(con, sizeof (con->out_connect),
                                        &con->out_connect);
        if (auth && auth->authorizer_buf_len)
@@ -834,7 +905,7 @@ static int prepare_write_connect(struct ceph_connection *con)
                                        auth->authorizer_buf);
 
        con->out_more = 0;
-       set_bit(WRITE_PENDING, &con->flags);
+       set_bit(CON_FLAG_WRITE_PENDING, &con->flags);
 
        return 0;
 }
@@ -882,30 +953,34 @@ out:
        return ret;  /* done! */
 }
 
-#ifdef CONFIG_BLOCK
-static void init_bio_iter(struct bio *bio, struct bio **iter, int *seg)
+static void out_msg_pos_next(struct ceph_connection *con, struct page *page,
+                       size_t len, size_t sent, bool in_trail)
 {
-       if (!bio) {
-               *iter = NULL;
-               *seg = 0;
-               return;
-       }
-       *iter = bio;
-       *seg = bio->bi_idx;
-}
+       struct ceph_msg *msg = con->out_msg;
 
-static void iter_bio_next(struct bio **bio_iter, int *seg)
-{
-       if (*bio_iter == NULL)
-               return;
+       BUG_ON(!msg);
+       BUG_ON(!sent);
 
-       BUG_ON(*seg >= (*bio_iter)->bi_vcnt);
+       con->out_msg_pos.data_pos += sent;
+       con->out_msg_pos.page_pos += sent;
+       if (sent < len)
+               return;
 
-       (*seg)++;
-       if (*seg == (*bio_iter)->bi_vcnt)
-               init_bio_iter((*bio_iter)->bi_next, bio_iter, seg);
-}
+       BUG_ON(sent != len);
+       con->out_msg_pos.page_pos = 0;
+       con->out_msg_pos.page++;
+       con->out_msg_pos.did_page_crc = false;
+       if (in_trail)
+               list_move_tail(&page->lru,
+                              &msg->trail->head);
+       else if (msg->pagelist)
+               list_move_tail(&page->lru,
+                              &msg->pagelist->head);
+#ifdef CONFIG_BLOCK
+       else if (msg->bio)
+               iter_bio_next(&msg->bio_iter, &msg->bio_seg);
 #endif
+}
 
 /*
  * Write as much message data payload as we can.  If we finish, queue
@@ -922,41 +997,36 @@ static int write_partial_msg_pages(struct ceph_connection *con)
        bool do_datacrc = !con->msgr->nocrc;
        int ret;
        int total_max_write;
-       int in_trail = 0;
-       size_t trail_len = (msg->trail ? msg->trail->length : 0);
+       bool in_trail = false;
+       const size_t trail_len = (msg->trail ? msg->trail->length : 0);
+       const size_t trail_off = data_len - trail_len;
 
        dout("write_partial_msg_pages %p msg %p page %d/%d offset %d\n",
-            con, con->out_msg, con->out_msg_pos.page, con->out_msg->nr_pages,
+            con, msg, con->out_msg_pos.page, msg->nr_pages,
             con->out_msg_pos.page_pos);
 
-#ifdef CONFIG_BLOCK
-       if (msg->bio && !msg->bio_iter)
-               init_bio_iter(msg->bio, &msg->bio_iter, &msg->bio_seg);
-#endif
-
+       /*
+        * Iterate through each page that contains data to be
+        * written, and send as much as possible for each.
+        *
+        * If we are calculating the data crc (the default), we will
+        * need to map the page.  If we have no pages, they have
+        * been revoked, so use the zero page.
+        */
        while (data_len > con->out_msg_pos.data_pos) {
                struct page *page = NULL;
                int max_write = PAGE_SIZE;
                int bio_offset = 0;
 
-               total_max_write = data_len - trail_len -
-                       con->out_msg_pos.data_pos;
-
-               /*
-                * if we are calculating the data crc (the default), we need
-                * to map the page.  if our pages[] has been revoked, use the
-                * zero page.
-                */
-
-               /* have we reached the trail part of the data? */
-               if (con->out_msg_pos.data_pos >= data_len - trail_len) {
-                       in_trail = 1;
+               in_trail = in_trail || con->out_msg_pos.data_pos >= trail_off;
+               if (!in_trail)
+                       total_max_write = trail_off - con->out_msg_pos.data_pos;
 
+               if (in_trail) {
                        total_max_write = data_len - con->out_msg_pos.data_pos;
 
                        page = list_first_entry(&msg->trail->head,
                                                struct page, lru);
-                       max_write = PAGE_SIZE;
                } else if (msg->pages) {
                        page = msg->pages[con->out_msg_pos.page];
                } else if (msg->pagelist) {
@@ -979,15 +1049,14 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 
                if (do_datacrc && !con->out_msg_pos.did_page_crc) {
                        void *base;
-                       u32 crc;
-                       u32 tmpcrc = le32_to_cpu(con->out_msg->footer.data_crc);
+                       u32 crc = le32_to_cpu(msg->footer.data_crc);
                        char *kaddr;
 
                        kaddr = kmap(page);
                        BUG_ON(kaddr == NULL);
                        base = kaddr + con->out_msg_pos.page_pos + bio_offset;
-                       crc = crc32c(tmpcrc, base, len);
-                       con->out_msg->footer.data_crc = cpu_to_le32(crc);
+                       crc = crc32c(crc, base, len);
+                       msg->footer.data_crc = cpu_to_le32(crc);
                        con->out_msg_pos.did_page_crc = true;
                }
                ret = ceph_tcp_sendpage(con->sock, page,
@@ -1000,30 +1069,14 @@ static int write_partial_msg_pages(struct ceph_connection *con)
                if (ret <= 0)
                        goto out;
 
-               con->out_msg_pos.data_pos += ret;
-               con->out_msg_pos.page_pos += ret;
-               if (ret == len) {
-                       con->out_msg_pos.page_pos = 0;
-                       con->out_msg_pos.page++;
-                       con->out_msg_pos.did_page_crc = false;
-                       if (in_trail)
-                               list_move_tail(&page->lru,
-                                              &msg->trail->head);
-                       else if (msg->pagelist)
-                               list_move_tail(&page->lru,
-                                              &msg->pagelist->head);
-#ifdef CONFIG_BLOCK
-                       else if (msg->bio)
-                               iter_bio_next(&msg->bio_iter, &msg->bio_seg);
-#endif
-               }
+               out_msg_pos_next(con, page, len, (size_t) ret, in_trail);
        }
 
        dout("write_partial_msg_pages %p msg %p done\n", con, msg);
 
        /* prepare and queue up footer, too */
        if (!do_datacrc)
-               con->out_msg->footer.flags |= CEPH_MSG_FOOTER_NOCRC;
+               msg->footer.flags |= CEPH_MSG_FOOTER_NOCRC;
        con_out_kvec_reset(con);
        prepare_write_message_footer(con);
        ret = 1;
@@ -1436,15 +1489,14 @@ static int process_banner(struct ceph_connection *con)
                     ceph_pr_addr(&con->msgr->inst.addr.in_addr));
        }
 
-       set_bit(NEGOTIATING, &con->state);
-       prepare_read_connect(con);
        return 0;
 }
 
 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)
@@ -1487,7 +1539,6 @@ static int process_connect(struct ceph_connection *con)
                        return -1;
                }
                con->auth_retry = 1;
-               con_out_kvec_reset(con);
                ret = prepare_write_connect(con);
                if (ret < 0)
                        return ret;
@@ -1503,12 +1554,11 @@ static int process_connect(struct ceph_connection *con)
                 * dropped messages.
                 */
                dout("process_connect got RESET peer seq %u\n",
-                    le32_to_cpu(con->in_connect.connect_seq));
+                    le32_to_cpu(con->in_reply.connect_seq));
                pr_err("%s%lld %s connection reset\n",
                       ENTITY_NAME(con->peer_name),
                       ceph_pr_addr(&con->peer_addr.in_addr));
                reset_connection(con);
-               con_out_kvec_reset(con);
                ret = prepare_write_connect(con);
                if (ret < 0)
                        return ret;
@@ -1520,8 +1570,7 @@ static int process_connect(struct ceph_connection *con)
                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;
 
@@ -1530,11 +1579,10 @@ static int process_connect(struct ceph_connection *con)
                 * If we sent a smaller connect_seq than the peer has, try
                 * again with a larger value.
                 */
-               dout("process_connect got RETRY my seq = %u, peer_seq = %u\n",
+               dout("process_connect got RETRY_SESSION my seq %u, peer %u\n",
                     le32_to_cpu(con->out_connect.connect_seq),
-                    le32_to_cpu(con->in_connect.connect_seq));
-               con->connect_seq = le32_to_cpu(con->in_connect.connect_seq);
-               con_out_kvec_reset(con);
+                    le32_to_cpu(con->in_reply.connect_seq));
+               con->connect_seq = le32_to_cpu(con->in_reply.connect_seq);
                ret = prepare_write_connect(con);
                if (ret < 0)
                        return ret;
@@ -1548,10 +1596,9 @@ static int process_connect(struct ceph_connection *con)
                 */
                dout("process_connect got RETRY_GLOBAL my %u peer_gseq %u\n",
                     con->peer_global_seq,
-                    le32_to_cpu(con->in_connect.global_seq));
+                    le32_to_cpu(con->in_reply.global_seq));
                get_global_seq(con->msgr,
-                              le32_to_cpu(con->in_connect.global_seq));
-               con_out_kvec_reset(con);
+                              le32_to_cpu(con->in_reply.global_seq));
                ret = prepare_write_connect(con);
                if (ret < 0)
                        return ret;
@@ -1569,7 +1616,10 @@ static int process_connect(struct ceph_connection *con)
                        fail_protocol(con);
                        return -1;
                }
-               clear_bit(CONNECTING, &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;
@@ -1581,7 +1631,9 @@ static int process_connect(struct ceph_connection *con)
                        le32_to_cpu(con->in_reply.connect_seq));
 
                if (con->in_reply.flags & CEPH_MSG_CONNECT_LOSSY)
-                       set_bit(LOSSYTX, &con->flags);
+                       set_bit(CON_FLAG_LOSSYTX, &con->flags);
+
+               con->delay = 0;      /* reset backoff memory */
 
                prepare_read_tag(con);
                break;
@@ -1712,9 +1764,6 @@ static int read_partial_message_bio(struct ceph_connection *con,
        void *p;
        int ret, left;
 
-       if (IS_ERR(bv))
-               return PTR_ERR(bv);
-
        left = min((int)(data_len - con->in_msg_pos.data_pos),
                   (int)(bv->bv_len - con->in_msg_pos.page_pos));
 
@@ -1831,6 +1880,11 @@ static int read_partial_message(struct ceph_connection *con)
                else
                        con->in_msg_pos.page_pos = 0;
                con->in_msg_pos.data_pos = 0;
+
+#ifdef CONFIG_BLOCK
+               if (m->bio)
+                       init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg);
+#endif
        }
 
        /* front */
@@ -1847,10 +1901,6 @@ static int read_partial_message(struct ceph_connection *con)
                if (ret <= 0)
                        return ret;
        }
-#ifdef CONFIG_BLOCK
-       if (m->bio && !m->bio_iter)
-               init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg);
-#endif
 
        /* (page) data */
        while (con->in_msg_pos.data_pos < data_len) {
@@ -1861,7 +1911,7 @@ static int read_partial_message(struct ceph_connection *con)
                                return ret;
 #ifdef CONFIG_BLOCK
                } else if (m->bio) {
-
+                       BUG_ON(!m->bio_iter);
                        ret = read_partial_message_bio(con,
                                                 &m->bio_iter, &m->bio_seg,
                                                 data_len, do_datacrc);
@@ -1919,7 +1969,7 @@ static void process_message(struct ceph_connection *con)
        con->in_msg->con = NULL;
        msg = con->in_msg;
        con->in_msg = NULL;
-       ceph_con_put(con);
+       con->ops->put(con);
 
        /* if first message, set peer_name */
        if (con->peer_name.type == 0)
@@ -1951,22 +2001,18 @@ static int try_write(struct ceph_connection *con)
 {
        int ret = 1;
 
-       dout("try_write start %p state %lu nref %d\n", con, con->state,
-            atomic_read(&con->nref));
+       dout("try_write start %p state %lu\n", con, con->state);
 
 more:
        dout("try_write out_kvec_bytes %d\n", con->out_kvec_bytes);
 
        /* open the socket first? */
-       if (con->sock == NULL) {
-               clear_bit(NEGOTIATING, &con->state);
-               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);
-               ret = prepare_write_connect(con);
-               if (ret < 0)
-                       goto out;
                prepare_read_banner(con);
 
                BUG_ON(con->in_msg);
@@ -2014,7 +2060,7 @@ more_kvec:
        }
 
 do_next:
-       if (!test_bit(CONNECTING, &con->state)) {
+       if (con->state == CON_STATE_OPEN) {
                /* is anything else pending? */
                if (!list_empty(&con->out_queue)) {
                        prepare_write_message(con);
@@ -2024,14 +2070,15 @@ do_next:
                        prepare_write_ack(con);
                        goto more;
                }
-               if (test_and_clear_bit(KEEPALIVE_PENDING, &con->flags)) {
+               if (test_and_clear_bit(CON_FLAG_KEEPALIVE_PENDING,
+                                      &con->flags)) {
                        prepare_write_keepalive(con);
                        goto more;
                }
        }
 
        /* Nothing to do! */
-       clear_bit(WRITE_PENDING, &con->flags);
+       clear_bit(CON_FLAG_WRITE_PENDING, &con->flags);
        dout("try_write nothing else to write.\n");
        ret = 0;
 out:
@@ -2048,38 +2095,42 @@ static int try_read(struct ceph_connection *con)
 {
        int ret = -1;
 
-       if (!con->sock)
-               return 0;
-
-       if (test_bit(STANDBY, &con->state))
+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;
 
-       dout("try_read start on %p\n", con);
+       BUG_ON(!con->sock);
 
-more:
        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;
+       if (con->state == CON_STATE_CONNECTING) {
+               dout("try_read connecting\n");
+               ret = read_partial_banner(con);
+               if (ret <= 0)
+                       goto out;
+               ret = process_banner(con);
+               if (ret < 0)
+                       goto out;
+
+               BUG_ON(con->state != CON_STATE_CONNECTING);
+               con->state = CON_STATE_NEGOTIATING;
+
+               /* Banner is good, exchange connection info */
+               ret = prepare_write_connect(con);
+               if (ret < 0)
+                       goto out;
+               prepare_read_connect(con);
+
+               /* Send connection info before awaiting response */
                goto out;
        }
 
-       if (test_bit(CONNECTING, &con->state)) {
-               if (!test_bit(NEGOTIATING, &con->state)) {
-                       dout("try_read connecting\n");
-                       ret = read_partial_banner(con);
-                       if (ret <= 0)
-                               goto out;
-                       ret = process_banner(con);
-                       if (ret < 0)
-                               goto out;
-               }
+       if (con->state == CON_STATE_NEGOTIATING) {
+               dout("try_read negotiating\n");
                ret = read_partial_connect(con);
                if (ret <= 0)
                        goto out;
@@ -2089,6 +2140,8 @@ more:
                goto more;
        }
 
+       BUG_ON(con->state != CON_STATE_OPEN);
+
        if (con->in_base_pos < 0) {
                /*
                 * skipping + discarding content.
@@ -2122,7 +2175,8 @@ more:
                        prepare_read_ack(con);
                        break;
                case CEPH_MSGR_TAG_CLOSE:
-                       set_bit(CLOSED, &con->state);   /* fixme */
+                       con_close_socket(con);
+                       con->state = CON_STATE_CLOSED;
                        goto out;
                default:
                        goto bad_tag;
@@ -2197,7 +2251,26 @@ static void con_work(struct work_struct *work)
 
        mutex_lock(&con->mutex);
 restart:
-       if (test_and_clear_bit(BACKOFF, &con->flags)) {
+       if (test_and_clear_bit(CON_FLAG_SOCK_CLOSED, &con->flags)) {
+               switch (con->state) {
+               case CON_STATE_CONNECTING:
+                       con->error_msg = "connection failed";
+                       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;
+       }
+
+       if (test_and_clear_bit(CON_FLAG_BACKOFF, &con->flags)) {
                dout("con_work %p backing off\n", con);
                if (queue_delayed_work(ceph_msgr_wq, &con->work,
                                       round_jiffies_relative(con->delay))) {
@@ -2211,35 +2284,35 @@ restart:
                }
        }
 
-       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)) { /* e.g. if we are replaced */
-               dout("con_work CLOSED\n");
-               con_close_socket(con);
+       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");
-               con_close_socket(con);
+               BUG_ON(con->sock);
        }
 
-       if (test_and_clear_bit(SOCK_CLOSED, &con->flags))
-               goto fault;
-
        ret = try_read(con);
        if (ret == -EAGAIN)
                goto restart;
-       if (ret < 0)
+       if (ret < 0) {
+               con->error_msg = "socket error on read";
                goto fault;
+       }
 
        ret = try_write(con);
        if (ret == -EAGAIN)
                goto restart;
-       if (ret < 0)
+       if (ret < 0) {
+               con->error_msg = "socket error on write";
                goto fault;
+       }
 
 done:
        mutex_unlock(&con->mutex);
@@ -2260,28 +2333,31 @@ fault:
  */
 static void ceph_fault(struct ceph_connection *con)
 {
+       mutex_lock(&con->mutex);
+
        pr_err("%s%lld %s %s\n", ENTITY_NAME(con->peer_name),
               ceph_pr_addr(&con->peer_addr.in_addr), con->error_msg);
        dout("fault %p state %lu to peer %s\n",
             con, con->state, ceph_pr_addr(&con->peer_addr.in_addr));
 
-       if (test_bit(LOSSYTX, &con->flags)) {
-               dout("fault on LOSSYTX channel\n");
-               goto out;
-       }
-
-       mutex_lock(&con->mutex);
-       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(CON_FLAG_LOSSYTX, &con->flags)) {
+               dout("fault on LOSSYTX channel, marking CLOSED\n");
+               con->state = CON_STATE_CLOSED;
+               goto out_unlock;
+       }
+
        if (con->in_msg) {
                BUG_ON(con->in_msg->con != con);
                con->in_msg->con = NULL;
                ceph_msg_put(con->in_msg);
                con->in_msg = NULL;
-               ceph_con_put(con);
+               con->ops->put(con);
        }
 
        /* Requeue anything that hasn't been acked */
@@ -2290,12 +2366,13 @@ static void ceph_fault(struct ceph_connection *con)
        /* If there are no messages queued or keepalive pending, place
         * the connection in a STANDBY state */
        if (list_empty(&con->out_queue) &&
-           !test_bit(KEEPALIVE_PENDING, &con->flags)) {
+           !test_bit(CON_FLAG_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);
+               clear_bit(CON_FLAG_WRITE_PENDING, &con->flags);
+               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)
@@ -2316,13 +2393,12 @@ static void ceph_fault(struct ceph_connection *con)
                         * that when con_work restarts we schedule the
                         * delay then.
                         */
-                       set_bit(BACKOFF, &con->flags);
+                       set_bit(CON_FLAG_BACKOFF, &con->flags);
                }
        }
 
 out_unlock:
        mutex_unlock(&con->mutex);
-out:
        /*
         * in case we faulted due to authentication, invalidate our
         * current tickets so that we can get new ones.
@@ -2361,6 +2437,8 @@ void ceph_messenger_init(struct ceph_messenger *msgr,
        encode_my_addr(msgr);
        msgr->nocrc = nocrc;
 
+       atomic_set(&msgr->stopping, 0);
+
        dout("%s %p\n", __func__, msgr);
 }
 EXPORT_SYMBOL(ceph_messenger_init);
@@ -2368,13 +2446,12 @@ EXPORT_SYMBOL(ceph_messenger_init);
 static void clear_standby(struct ceph_connection *con)
 {
        /* come back from STANDBY? */
-       if (test_and_clear_bit(STANDBY, &con->state)) {
-               mutex_lock(&con->mutex);
+       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));
-               mutex_unlock(&con->mutex);
+               WARN_ON(test_bit(CON_FLAG_WRITE_PENDING, &con->flags));
+               WARN_ON(test_bit(CON_FLAG_KEEPALIVE_PENDING, &con->flags));
        }
 }
 
@@ -2383,24 +2460,22 @@ static void clear_standby(struct ceph_connection *con)
  */
 void ceph_con_send(struct ceph_connection *con, struct ceph_msg *msg)
 {
-       if (test_bit(CLOSED, &con->state)) {
-               dout("con_send %p closed, dropping %p\n", con, msg);
-               ceph_msg_put(msg);
-               return;
-       }
-
        /* set src+dst */
        msg->hdr.src = con->msgr->inst.name;
-
        BUG_ON(msg->front.iov_len != le32_to_cpu(msg->hdr.front_len));
-
        msg->needs_out_seq = true;
 
-       /* queue */
        mutex_lock(&con->mutex);
 
+       if (con->state == CON_STATE_CLOSED) {
+               dout("con_send %p closed, dropping %p\n", con, msg);
+               ceph_msg_put(msg);
+               mutex_unlock(&con->mutex);
+               return;
+       }
+
        BUG_ON(msg->con != NULL);
-       msg->con = ceph_con_get(con);
+       msg->con = con->ops->get(con);
        BUG_ON(msg->con == NULL);
 
        BUG_ON(!list_empty(&msg->list_head));
@@ -2411,12 +2486,13 @@ void ceph_con_send(struct ceph_connection *con, struct ceph_msg *msg)
             le32_to_cpu(msg->hdr.front_len),
             le32_to_cpu(msg->hdr.middle_len),
             le32_to_cpu(msg->hdr.data_len));
+
+       clear_standby(con);
        mutex_unlock(&con->mutex);
 
        /* if there wasn't anything waiting to send before, queue
         * new work */
-       clear_standby(con);
-       if (test_and_set_bit(WRITE_PENDING, &con->flags) == 0)
+       if (test_and_set_bit(CON_FLAG_WRITE_PENDING, &con->flags) == 0)
                queue_con(con);
 }
 EXPORT_SYMBOL(ceph_con_send);
@@ -2436,7 +2512,7 @@ void ceph_msg_revoke(struct ceph_msg *msg)
                dout("%s %p msg %p - was on queue\n", __func__, con, msg);
                list_del_init(&msg->list_head);
                BUG_ON(msg->con == NULL);
-               ceph_con_put(msg->con);
+               msg->con->ops->put(msg->con);
                msg->con = NULL;
                msg->hdr.seq = 0;
 
@@ -2502,9 +2578,11 @@ void ceph_msg_revoke_incoming(struct ceph_msg *msg)
 void ceph_con_keepalive(struct ceph_connection *con)
 {
        dout("con_keepalive %p\n", con);
+       mutex_lock(&con->mutex);
        clear_standby(con);
-       if (test_and_set_bit(KEEPALIVE_PENDING, &con->flags) == 0 &&
-           test_and_set_bit(WRITE_PENDING, &con->flags) == 0)
+       mutex_unlock(&con->mutex);
+       if (test_and_set_bit(CON_FLAG_KEEPALIVE_PENDING, &con->flags) == 0 &&
+           test_and_set_bit(CON_FLAG_WRITE_PENDING, &con->flags) == 0)
                queue_con(con);
 }
 EXPORT_SYMBOL(ceph_con_keepalive);
@@ -2646,7 +2724,7 @@ static bool ceph_con_in_msg_alloc(struct ceph_connection *con,
                con->in_msg = con->ops->alloc_msg(con, hdr, &skip);
                mutex_lock(&con->mutex);
                if (con->in_msg) {
-                       con->in_msg->con = ceph_con_get(con);
+                       con->in_msg->con = con->ops->get(con);
                        BUG_ON(con->in_msg->con == NULL);
                }
                if (skip)
@@ -2662,7 +2740,7 @@ static bool ceph_con_in_msg_alloc(struct ceph_connection *con,
                               type, front_len);
                        return false;
                }
-               con->in_msg->con = ceph_con_get(con);
+               con->in_msg->con = con->ops->get(con);
                BUG_ON(con->in_msg->con == NULL);
                con->in_msg->page_alignment = le16_to_cpu(hdr->data_off);
        }