Merge branch 'drbd-8.4_ed6' into for-3.8-drivers-drbd-8.4_ed6
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / block / drbd / drbd_receiver.c
index 8f25095f390c4723072bf968673e25d1d07c5c05..0331ad0b61e18583fb8f5fc5b768134eba0fd6ad 100644 (file)
@@ -295,6 +295,9 @@ static void drbd_free_pages(struct drbd_conf *mdev, struct page *page, int is_ne
        atomic_t *a = is_net ? &mdev->pp_in_use_by_net : &mdev->pp_in_use;
        int i;
 
+       if (page == NULL)
+               return;
+
        if (drbd_pp_vacant > (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * minor_count)
                i = page_chain_free(page);
        else {
@@ -331,7 +334,7 @@ drbd_alloc_peer_req(struct drbd_conf *mdev, u64 id, sector_t sector,
                    unsigned int data_size, gfp_t gfp_mask) __must_hold(local)
 {
        struct drbd_peer_request *peer_req;
-       struct page *page;
+       struct page *page = NULL;
        unsigned nr_pages = (data_size + PAGE_SIZE -1) >> PAGE_SHIFT;
 
        if (drbd_insert_fault(mdev, DRBD_FAULT_AL_EE))
@@ -344,9 +347,11 @@ drbd_alloc_peer_req(struct drbd_conf *mdev, u64 id, sector_t sector,
                return NULL;
        }
 
-       page = drbd_alloc_pages(mdev, nr_pages, (gfp_mask & __GFP_WAIT));
-       if (!page)
-               goto fail;
+       if (data_size) {
+               page = drbd_alloc_pages(mdev, nr_pages, (gfp_mask & __GFP_WAIT));
+               if (!page)
+                       goto fail;
+       }
 
        drbd_clear_interval(&peer_req->i);
        peer_req->i.size = data_size;
@@ -420,7 +425,7 @@ static int drbd_finish_peer_reqs(struct drbd_conf *mdev)
                drbd_free_net_peer_req(mdev, peer_req);
 
        /* possible callbacks here:
-        * e_end_block, and e_end_resync_block, e_send_discard_write.
+        * e_end_block, and e_end_resync_block, e_send_superseded.
         * all ignore the last argument.
         */
        list_for_each_entry_safe(peer_req, t, &work_list, w.list) {
@@ -461,33 +466,6 @@ static void drbd_wait_ee_list_empty(struct drbd_conf *mdev,
        spin_unlock_irq(&mdev->tconn->req_lock);
 }
 
-/* see also kernel_accept; which is only present since 2.6.18.
- * also we want to log which part of it failed, exactly */
-static int drbd_accept(const char **what, struct socket *sock, struct socket **newsock)
-{
-       struct sock *sk = sock->sk;
-       int err = 0;
-
-       *what = "sock_create_lite";
-       err = sock_create_lite(sk->sk_family, sk->sk_type, sk->sk_protocol,
-                              newsock);
-       if (err < 0)
-               goto out;
-
-       *what = "accept";
-       err = sock->ops->accept(sock, *newsock, 0);
-       if (err < 0) {
-               sock_release(*newsock);
-               *newsock = NULL;
-               goto out;
-       }
-       (*newsock)->ops  = sock->ops;
-       __module_get((*newsock)->ops->owner);
-
-out:
-       return err;
-}
-
 static int drbd_recv_short(struct socket *sock, void *buf, size_t size, int flags)
 {
        mm_segment_t oldfs;
@@ -512,54 +490,34 @@ static int drbd_recv_short(struct socket *sock, void *buf, size_t size, int flag
 
 static int drbd_recv(struct drbd_tconn *tconn, void *buf, size_t size)
 {
-       mm_segment_t oldfs;
-       struct kvec iov = {
-               .iov_base = buf,
-               .iov_len = size,
-       };
-       struct msghdr msg = {
-               .msg_iovlen = 1,
-               .msg_iov = (struct iovec *)&iov,
-               .msg_flags = MSG_WAITALL | MSG_NOSIGNAL
-       };
        int rv;
 
-       oldfs = get_fs();
-       set_fs(KERNEL_DS);
+       rv = drbd_recv_short(tconn->data.socket, buf, size, 0);
 
-       for (;;) {
-               rv = sock_recvmsg(tconn->data.socket, &msg, size, msg.msg_flags);
-               if (rv == size)
-                       break;
+       if (rv < 0) {
+               if (rv == -ECONNRESET)
+                       conn_info(tconn, "sock was reset by peer\n");
+               else if (rv != -ERESTARTSYS)
+                       conn_err(tconn, "sock_recvmsg returned %d\n", rv);
+       } else if (rv == 0) {
+               if (test_bit(DISCONNECT_SENT, &tconn->flags)) {
+                       long t;
+                       rcu_read_lock();
+                       t = rcu_dereference(tconn->net_conf)->ping_timeo * HZ/10;
+                       rcu_read_unlock();
 
-               /* Note:
-                * ECONNRESET   other side closed the connection
-                * ERESTARTSYS  (on  sock) we got a signal
-                */
+                       t = wait_event_timeout(tconn->ping_wait, tconn->cstate < C_WF_REPORT_PARAMS, t);
 
-               if (rv < 0) {
-                       if (rv == -ECONNRESET)
-                               conn_info(tconn, "sock was reset by peer\n");
-                       else if (rv != -ERESTARTSYS)
-                               conn_err(tconn, "sock_recvmsg returned %d\n", rv);
-                       break;
-               } else if (rv == 0) {
-                       conn_info(tconn, "sock was shut down by peer\n");
-                       break;
-               } else  {
-                       /* signal came in, or peer/link went down,
-                        * after we read a partial message
-                        */
-                       /* D_ASSERT(signal_pending(current)); */
-                       break;
+                       if (t)
+                               goto out;
                }
-       };
-
-       set_fs(oldfs);
+               conn_info(tconn, "sock was shut down by peer\n");
+       }
 
        if (rv != size)
                conn_request_state(tconn, NS(conn, C_BROKEN_PIPE), CS_HARD);
 
+out:
        return rv;
 }
 
@@ -693,12 +651,30 @@ out:
        return sock;
 }
 
-static struct socket *drbd_wait_for_connect(struct drbd_tconn *tconn)
+struct accept_wait_data {
+       struct drbd_tconn *tconn;
+       struct socket *s_listen;
+       struct completion door_bell;
+       void (*original_sk_state_change)(struct sock *sk);
+
+};
+
+static void drbd_incoming_connection(struct sock *sk)
 {
-       int timeo, err, my_addr_len;
-       int sndbuf_size, rcvbuf_size, connect_int;
-       struct socket *s_estab = NULL, *s_listen;
+       struct accept_wait_data *ad = sk->sk_user_data;
+       void (*state_change)(struct sock *sk);
+
+       state_change = ad->original_sk_state_change;
+       if (sk->sk_state == TCP_ESTABLISHED)
+               complete(&ad->door_bell);
+       state_change(sk);
+}
+
+static int prepare_listen_socket(struct drbd_tconn *tconn, struct accept_wait_data *ad)
+{
+       int err, sndbuf_size, rcvbuf_size, my_addr_len;
        struct sockaddr_in6 my_addr;
+       struct socket *s_listen;
        struct net_conf *nc;
        const char *what;
 
@@ -706,11 +682,10 @@ static struct socket *drbd_wait_for_connect(struct drbd_tconn *tconn)
        nc = rcu_dereference(tconn->net_conf);
        if (!nc) {
                rcu_read_unlock();
-               return NULL;
+               return -EIO;
        }
        sndbuf_size = nc->sndbuf_size;
        rcvbuf_size = nc->rcvbuf_size;
-       connect_int = nc->connect_int;
        rcu_read_unlock();
 
        my_addr_len = min_t(int, tconn->my_addr_len, sizeof(struct sockaddr_in6));
@@ -718,18 +693,13 @@ static struct socket *drbd_wait_for_connect(struct drbd_tconn *tconn)
 
        what = "sock_create_kern";
        err = sock_create_kern(((struct sockaddr *)&my_addr)->sa_family,
-               SOCK_STREAM, IPPROTO_TCP, &s_listen);
+                              SOCK_STREAM, IPPROTO_TCP, &s_listen);
        if (err) {
                s_listen = NULL;
                goto out;
        }
 
-       timeo = connect_int * HZ;
-       timeo += (random32() & 1) ? timeo / 7 : -timeo / 7; /* 28.5% random jitter */
-
-       s_listen->sk->sk_reuse    = 1; /* SO_REUSEADDR */
-       s_listen->sk->sk_rcvtimeo = timeo;
-       s_listen->sk->sk_sndtimeo = timeo;
+       s_listen->sk->sk_reuse = SK_CAN_REUSE; /* SO_REUSEADDR */
        drbd_setbufsize(s_listen, sndbuf_size, rcvbuf_size);
 
        what = "bind before listen";
@@ -737,13 +707,19 @@ static struct socket *drbd_wait_for_connect(struct drbd_tconn *tconn)
        if (err < 0)
                goto out;
 
+       ad->s_listen = s_listen;
+       write_lock_bh(&s_listen->sk->sk_callback_lock);
+       ad->original_sk_state_change = s_listen->sk->sk_state_change;
+       s_listen->sk->sk_state_change = drbd_incoming_connection;
+       s_listen->sk->sk_user_data = ad;
+       write_unlock_bh(&s_listen->sk->sk_callback_lock);
+
        what = "listen";
        err = s_listen->ops->listen(s_listen, 5);
        if (err < 0)
                goto out;
 
-       err = drbd_accept(&what, s_listen, &s_estab);
-
+       return 0;
 out:
        if (s_listen)
                sock_release(s_listen);
@@ -754,6 +730,50 @@ out:
                }
        }
 
+       return -EIO;
+}
+
+static void unregister_state_change(struct sock *sk, struct accept_wait_data *ad)
+{
+       write_lock_bh(&sk->sk_callback_lock);
+       sk->sk_state_change = ad->original_sk_state_change;
+       sk->sk_user_data = NULL;
+       write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static struct socket *drbd_wait_for_connect(struct drbd_tconn *tconn, struct accept_wait_data *ad)
+{
+       int timeo, connect_int, err = 0;
+       struct socket *s_estab = NULL;
+       struct net_conf *nc;
+
+       rcu_read_lock();
+       nc = rcu_dereference(tconn->net_conf);
+       if (!nc) {
+               rcu_read_unlock();
+               return NULL;
+       }
+       connect_int = nc->connect_int;
+       rcu_read_unlock();
+
+       timeo = connect_int * HZ;
+       timeo += (random32() & 1) ? timeo / 7 : -timeo / 7; /* 28.5% random jitter */
+
+       err = wait_for_completion_interruptible_timeout(&ad->door_bell, timeo);
+       if (err <= 0)
+               return NULL;
+
+       err = kernel_accept(ad->s_listen, &s_estab, 0);
+       if (err < 0) {
+               if (err != -EAGAIN && err != -EINTR && err != -ERESTARTSYS) {
+                       conn_err(tconn, "accept failed, err = %d\n", err);
+                       conn_request_state(tconn, NS(conn, C_DISCONNECTING), CS_HARD);
+               }
+       }
+
+       if (s_estab)
+               unregister_state_change(s_estab->sk, ad);
+
        return s_estab;
 }
 
@@ -846,10 +866,15 @@ static int conn_connect(struct drbd_tconn *tconn)
        struct drbd_socket sock, msock;
        struct drbd_conf *mdev;
        struct net_conf *nc;
-       int vnr, timeout, try, h, ok;
+       int vnr, timeout, h, ok;
        bool discard_my_data;
        enum drbd_state_rv rv;
+       struct accept_wait_data ad = {
+               .tconn = tconn,
+               .door_bell = COMPLETION_INITIALIZER_ONSTACK(ad.door_bell),
+       };
 
+       clear_bit(DISCONNECT_SENT, &tconn->flags);
        if (conn_request_state(tconn, NS(conn, C_WF_CONNECTION), CS_VERBOSE) < SS_SUCCESS)
                return -2;
 
@@ -862,28 +887,22 @@ static int conn_connect(struct drbd_tconn *tconn)
        msock.rbuf = tconn->meta.rbuf;
        msock.socket = NULL;
 
-       clear_bit(DISCARD_CONCURRENT, &tconn->flags);
-
        /* Assume that the peer only understands protocol 80 until we know better.  */
        tconn->agreed_pro_version = 80;
 
+       if (prepare_listen_socket(tconn, &ad))
+               return 0;
+
        do {
                struct socket *s;
 
-               for (try = 0;;) {
-                       /* 3 tries, this should take less than a second! */
-                       s = drbd_try_connect(tconn);
-                       if (s || ++try >= 3)
-                               break;
-                       /* give the other side time to call bind() & listen() */
-                       schedule_timeout_interruptible(HZ / 10);
-               }
-
+               s = drbd_try_connect(tconn);
                if (s) {
                        if (!sock.socket) {
                                sock.socket = s;
                                send_first_packet(tconn, &sock, P_INITIAL_DATA);
                        } else if (!msock.socket) {
+                               clear_bit(RESOLVE_CONFLICTS, &tconn->flags);
                                msock.socket = s;
                                send_first_packet(tconn, &msock, P_INITIAL_META);
                        } else {
@@ -905,30 +924,35 @@ static int conn_connect(struct drbd_tconn *tconn)
                }
 
 retry:
-               s = drbd_wait_for_connect(tconn);
+               s = drbd_wait_for_connect(tconn, &ad);
                if (s) {
-                       try = receive_first_packet(tconn, s);
+                       int fp = receive_first_packet(tconn, s);
                        drbd_socket_okay(&sock.socket);
                        drbd_socket_okay(&msock.socket);
-                       switch (try) {
+                       switch (fp) {
                        case P_INITIAL_DATA:
                                if (sock.socket) {
                                        conn_warn(tconn, "initial packet S crossed\n");
                                        sock_release(sock.socket);
+                                       sock.socket = s;
+                                       goto randomize;
                                }
                                sock.socket = s;
                                break;
                        case P_INITIAL_META:
+                               set_bit(RESOLVE_CONFLICTS, &tconn->flags);
                                if (msock.socket) {
                                        conn_warn(tconn, "initial packet M crossed\n");
                                        sock_release(msock.socket);
+                                       msock.socket = s;
+                                       goto randomize;
                                }
                                msock.socket = s;
-                               set_bit(DISCARD_CONCURRENT, &tconn->flags);
                                break;
                        default:
                                conn_warn(tconn, "Error receiving initial packet\n");
                                sock_release(s);
+randomize:
                                if (random32() & 1)
                                        goto retry;
                        }
@@ -943,16 +967,15 @@ retry:
                                goto out_release_sockets;
                }
 
-               if (sock.socket && &msock.socket) {
-                       ok = drbd_socket_okay(&sock.socket);
-                       ok = drbd_socket_okay(&msock.socket) && ok;
-                       if (ok)
-                               break;
-               }
-       } while (1);
+               ok = drbd_socket_okay(&sock.socket);
+               ok = drbd_socket_okay(&msock.socket) && ok;
+       } while (!ok);
+
+       if (ad.s_listen)
+               sock_release(ad.s_listen);
 
-       sock.socket->sk->sk_reuse = 1; /* SO_REUSEADDR */
-       msock.socket->sk->sk_reuse = 1; /* SO_REUSEADDR */
+       sock.socket->sk->sk_reuse = SK_CAN_REUSE; /* SO_REUSEADDR */
+       msock.socket->sk->sk_reuse = SK_CAN_REUSE; /* SO_REUSEADDR */
 
        sock.socket->sk->sk_allocation = GFP_NOIO;
        msock.socket->sk->sk_allocation = GFP_NOIO;
@@ -1046,6 +1069,8 @@ retry:
        return h;
 
 out_release_sockets:
+       if (ad.s_listen)
+               sock_release(ad.s_listen);
        if (sock.socket)
                sock_release(sock.socket);
        if (msock.socket)
@@ -1471,8 +1496,6 @@ read_in_block(struct drbd_conf *mdev, u64 id, sector_t sector,
                data_size -= dgs;
        }
 
-       if (!expect(data_size != 0))
-               return NULL;
        if (!expect(IS_ALIGNED(data_size, 512)))
                return NULL;
        if (!expect(data_size <= DRBD_MAX_BIO_SIZE))
@@ -1495,6 +1518,9 @@ read_in_block(struct drbd_conf *mdev, u64 id, sector_t sector,
        if (!peer_req)
                return NULL;
 
+       if (!data_size)
+               return peer_req;
+
        ds = data_size;
        page = peer_req->pages;
        page_chain_for_each(page) {
@@ -1763,7 +1789,7 @@ static void restart_conflicting_writes(struct drbd_conf *mdev,
                        continue;
                /* as it is RQ_POSTPONED, this will cause it to
                 * be queued on the retry workqueue. */
-               __req_mod(req, DISCARD_WRITE, NULL);
+               __req_mod(req, CONFLICT_RESOLVED, NULL);
        }
 }
 
@@ -1824,9 +1850,9 @@ static int e_send_ack(struct drbd_work *w, enum drbd_packet ack)
        return err;
 }
 
-static int e_send_discard_write(struct drbd_work *w, int unused)
+static int e_send_superseded(struct drbd_work *w, int unused)
 {
-       return e_send_ack(w, P_DISCARD_WRITE);
+       return e_send_ack(w, P_SUPERSEDED);
 }
 
 static int e_send_retry_write(struct drbd_work *w, int unused)
@@ -1834,7 +1860,7 @@ static int e_send_retry_write(struct drbd_work *w, int unused)
        struct drbd_tconn *tconn = w->mdev->tconn;
 
        return e_send_ack(w, tconn->agreed_pro_version >= 100 ?
-                            P_RETRY_WRITE : P_DISCARD_WRITE);
+                            P_RETRY_WRITE : P_SUPERSEDED);
 }
 
 static bool seq_greater(u32 a, u32 b)
@@ -1859,7 +1885,7 @@ static bool need_peer_seq(struct drbd_conf *mdev)
 
        /*
         * We only need to keep track of the last packet_seq number of our peer
-        * if we are in dual-primary mode and we have the discard flag set; see
+        * if we are in dual-primary mode and we have the resolve-conflicts flag set; see
         * handle_write_conflicts().
         */
 
@@ -1867,7 +1893,7 @@ static bool need_peer_seq(struct drbd_conf *mdev)
        tp = rcu_dereference(mdev->tconn->net_conf)->two_primaries;
        rcu_read_unlock();
 
-       return tp && test_bit(DISCARD_CONCURRENT, &tconn->flags);
+       return tp && test_bit(RESOLVE_CONFLICTS, &tconn->flags);
 }
 
 static void update_peer_seq(struct drbd_conf *mdev, unsigned int peer_seq)
@@ -2008,7 +2034,7 @@ static int handle_write_conflicts(struct drbd_conf *mdev,
                                  struct drbd_peer_request *peer_req)
 {
        struct drbd_tconn *tconn = mdev->tconn;
-       bool resolve_conflicts = test_bit(DISCARD_CONCURRENT, &tconn->flags);
+       bool resolve_conflicts = test_bit(RESOLVE_CONFLICTS, &tconn->flags);
        sector_t sector = peer_req->i.sector;
        const unsigned int size = peer_req->i.size;
        struct drbd_interval *i;
@@ -2042,11 +2068,11 @@ static int handle_write_conflicts(struct drbd_conf *mdev,
                if (resolve_conflicts) {
                        /*
                         * If the peer request is fully contained within the
-                        * overlapping request, it can be discarded; otherwise,
-                        * it will be retried once all overlapping requests
-                        * have completed.
+                        * overlapping request, it can be considered overwritten
+                        * and thus superseded; otherwise, it will be retried
+                        * once all overlapping requests have completed.
                         */
-                       bool discard = i->sector <= sector && i->sector +
+                       bool superseded = i->sector <= sector && i->sector +
                                       (i->size >> 9) >= sector + (size >> 9);
 
                        if (!equal)
@@ -2055,10 +2081,10 @@ static int handle_write_conflicts(struct drbd_conf *mdev,
                                               "assuming %s came first\n",
                                          (unsigned long long)i->sector, i->size,
                                          (unsigned long long)sector, size,
-                                         discard ? "local" : "remote");
+                                         superseded ? "local" : "remote");
 
                        inc_unacked(mdev);
-                       peer_req->w.cb = discard ? e_send_discard_write :
+                       peer_req->w.cb = superseded ? e_send_superseded :
                                                   e_send_retry_write;
                        list_add_tail(&peer_req->w.list, &mdev->done_ee);
                        wake_asender(mdev->tconn);
@@ -2079,8 +2105,9 @@ static int handle_write_conflicts(struct drbd_conf *mdev,
                            !(req->rq_state & RQ_POSTPONED)) {
                                /*
                                 * Wait for the node with the discard flag to
-                                * decide if this request will be discarded or
-                                * retried.  Requests that are discarded will
+                                * decide if this request has been superseded
+                                * or needs to be retried.
+                                * Requests that have been superseded will
                                 * disappear from the write_requests tree.
                                 *
                                 * In addition, wait for the conflicting
@@ -2157,6 +2184,10 @@ static int receive_Data(struct drbd_tconn *tconn, struct packet_info *pi)
 
        dp_flags = be32_to_cpu(p->dp_flags);
        rw |= wire_flags_to_bio(mdev, dp_flags);
+       if (peer_req->pages == NULL) {
+               D_ASSERT(peer_req->i.size == 0);
+               D_ASSERT(dp_flags & DP_FLUSH);
+       }
 
        if (dp_flags & DP_MAY_SET_IN_SYNC)
                peer_req->flags |= EE_MAY_SET_IN_SYNC;
@@ -2555,7 +2586,7 @@ static int drbd_asb_recover_0p(struct drbd_conf *mdev) __must_hold(local)
                     "Using discard-least-changes instead\n");
        case ASB_DISCARD_ZERO_CHG:
                if (ch_peer == 0 && ch_self == 0) {
-                       rv = test_bit(DISCARD_CONCURRENT, &mdev->tconn->flags)
+                       rv = test_bit(RESOLVE_CONFLICTS, &mdev->tconn->flags)
                                ? -1 : 1;
                        break;
                } else {
@@ -2571,7 +2602,7 @@ static int drbd_asb_recover_0p(struct drbd_conf *mdev) __must_hold(local)
                        rv =  1;
                else /* ( ch_self == ch_peer ) */
                     /* Well, then use something else. */
-                       rv = test_bit(DISCARD_CONCURRENT, &mdev->tconn->flags)
+                       rv = test_bit(RESOLVE_CONFLICTS, &mdev->tconn->flags)
                                ? -1 : 1;
                break;
        case ASB_DISCARD_LOCAL:
@@ -2746,7 +2777,9 @@ static int drbd_uuid_compare(struct drbd_conf *mdev, int *rule_nr) __must_hold(l
                        if ((mdev->ldev->md.uuid[UI_BITMAP] & ~((u64)1)) == (mdev->p_uuid[UI_HISTORY_START] & ~((u64)1)) &&
                            (mdev->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1)) == (mdev->p_uuid[UI_HISTORY_START + 1] & ~((u64)1))) {
                                dev_info(DEV, "was SyncSource, missed the resync finished event, corrected myself:\n");
-                               drbd_uuid_set_bm(mdev, 0UL);
+                               drbd_uuid_move_history(mdev);
+                               mdev->ldev->md.uuid[UI_HISTORY_START] = mdev->ldev->md.uuid[UI_BITMAP];
+                               mdev->ldev->md.uuid[UI_BITMAP] = 0;
 
                                drbd_uuid_dump(mdev, "self", mdev->ldev->md.uuid,
                                               mdev->state.disk >= D_NEGOTIATING ? drbd_bm_total_weight(mdev) : 0, 0);
@@ -2794,7 +2827,7 @@ static int drbd_uuid_compare(struct drbd_conf *mdev, int *rule_nr) __must_hold(l
                case 1: /*  self_pri && !peer_pri */ return 1;
                case 2: /* !self_pri &&  peer_pri */ return -1;
                case 3: /*  self_pri &&  peer_pri */
-                       dc = test_bit(DISCARD_CONCURRENT, &mdev->tconn->flags);
+                       dc = test_bit(RESOLVE_CONFLICTS, &mdev->tconn->flags);
                        return dc ? -1 : 1;
                }
        }
@@ -2854,8 +2887,8 @@ static int drbd_uuid_compare(struct drbd_conf *mdev, int *rule_nr) __must_hold(l
                        if (mdev->tconn->agreed_pro_version < 91)
                                return -1091;
 
-                       _drbd_uuid_set(mdev, UI_BITMAP, mdev->ldev->md.uuid[UI_HISTORY_START]);
-                       _drbd_uuid_set(mdev, UI_HISTORY_START, mdev->ldev->md.uuid[UI_HISTORY_START + 1]);
+                       __drbd_uuid_set(mdev, UI_BITMAP, mdev->ldev->md.uuid[UI_HISTORY_START]);
+                       __drbd_uuid_set(mdev, UI_HISTORY_START, mdev->ldev->md.uuid[UI_HISTORY_START + 1]);
 
                        dev_info(DEV, "Last syncUUID did not get through, corrected:\n");
                        drbd_uuid_dump(mdev, "self", mdev->ldev->md.uuid,
@@ -2909,11 +2942,14 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_conf *mdev, enum drbd_rol
                mydisk = mdev->new_state_tmp.disk;
 
        dev_info(DEV, "drbd_sync_handshake:\n");
+
+       spin_lock_irq(&mdev->ldev->md.uuid_lock);
        drbd_uuid_dump(mdev, "self", mdev->ldev->md.uuid, mdev->comm_bm_set, 0);
        drbd_uuid_dump(mdev, "peer", mdev->p_uuid,
                       mdev->p_uuid[UI_SIZE], mdev->p_uuid[UI_FLAGS]);
 
        hg = drbd_uuid_compare(mdev, &rule_nr);
+       spin_unlock_irq(&mdev->ldev->md.uuid_lock);
 
        dev_info(DEV, "uuid_compare()=%d by rule %d\n", hg, rule_nr);
 
@@ -3730,7 +3766,7 @@ static int receive_req_state(struct drbd_tconn *tconn, struct packet_info *pi)
        mask.i = be32_to_cpu(p->mask);
        val.i = be32_to_cpu(p->val);
 
-       if (test_bit(DISCARD_CONCURRENT, &mdev->tconn->flags) &&
+       if (test_bit(RESOLVE_CONFLICTS, &mdev->tconn->flags) &&
            mutex_is_locked(mdev->state_mutex)) {
                drbd_send_sr_reply(mdev, SS_CONCURRENT_ST_CHG);
                return 0;
@@ -3756,7 +3792,7 @@ static int receive_req_conn_state(struct drbd_tconn *tconn, struct packet_info *
        mask.i = be32_to_cpu(p->mask);
        val.i = be32_to_cpu(p->val);
 
-       if (test_bit(DISCARD_CONCURRENT, &tconn->flags) &&
+       if (test_bit(RESOLVE_CONFLICTS, &tconn->flags) &&
            mutex_is_locked(&tconn->cstate_mutex)) {
                conn_send_sr_reply(tconn, SS_CONCURRENT_ST_CHG);
                return 0;
@@ -3801,7 +3837,7 @@ static int receive_state(struct drbd_tconn *tconn, struct packet_info *pi)
         * already decided to close the connection again,
         * we must not "re-establish" it here. */
        if (os.conn <= C_TEAR_DOWN)
-               return false;
+               return -ECONNRESET;
 
        /* If this is the "end of sync" confirmation, usually the peer disk
         * transitions from D_INCONSISTENT to D_UP_TO_DATE. For empty (0 bits
@@ -3833,6 +3869,14 @@ static int receive_state(struct drbd_tconn *tconn, struct packet_info *pi)
                }
        }
 
+       /* explicit verify finished notification, stop sector reached. */
+       if (os.conn == C_VERIFY_T && os.disk == D_UP_TO_DATE &&
+           peer_state.conn == C_CONNECTED && real_peer_disk == D_UP_TO_DATE) {
+               ov_out_of_sync_print(mdev);
+               drbd_resync_finished(mdev);
+               return 0;
+       }
+
        /* peer says his disk is inconsistent, while we think it is uptodate,
         * and this happens while the peer still thinks we have a sync going on,
         * but we think we are already done with the sync.
@@ -4371,7 +4415,7 @@ void conn_flush_workqueue(struct drbd_tconn *tconn)
        barr.w.cb = w_prev_work_done;
        barr.w.tconn = tconn;
        init_completion(&barr.done);
-       drbd_queue_work(&tconn->data.work, &barr.w);
+       drbd_queue_work(&tconn->sender_work, &barr.w);
        wait_for_completion(&barr.done);
 }
 
@@ -4409,6 +4453,7 @@ static void conn_disconnect(struct drbd_tconn *tconn)
                conn_err(tconn, "ASSERTION FAILED: tconn->current_epoch->list not empty\n");
        /* ok, no more ee's on the fly, it is safe to reset the epoch_size */
        atomic_set(&tconn->current_epoch->epoch_size, 0);
+       tconn->send.seen_any_write_yet = false;
 
        conn_info(tconn, "Connection closed\n");
 
@@ -4468,6 +4513,10 @@ static int drbd_disconnected(struct drbd_conf *mdev)
           necessary to reclain net_ee in drbd_finish_peer_reqs(). */
        drbd_flush_workqueue(mdev);
 
+       /* need to do it again, drbd_finish_peer_reqs() may have populated it
+        * again via drbd_try_clear_on_disk_bm(). */
+       drbd_rs_cancel_all(mdev);
+
        kfree(mdev->p_uuid);
        mdev->p_uuid = NULL;
 
@@ -4941,8 +4990,8 @@ static int got_BlockAck(struct drbd_tconn *tconn, struct packet_info *pi)
        case P_RECV_ACK:
                what = RECV_ACKED_BY_PEER;
                break;
-       case P_DISCARD_WRITE:
-               what = DISCARD_WRITE;
+       case P_SUPERSEDED:
+               what = CONFLICT_RESOLVED;
                break;
        case P_RETRY_WRITE:
                what = POSTPONE_WRITE;
@@ -5105,7 +5154,7 @@ static int got_OVResult(struct drbd_tconn *tconn, struct packet_info *pi)
                if (w) {
                        w->cb = w_ov_finished;
                        w->mdev = mdev;
-                       drbd_queue_work_front(&mdev->tconn->data.work, w);
+                       drbd_queue_work(&mdev->tconn->sender_work, w);
                } else {
                        dev_err(DEV, "kmalloc(w) failed.");
                        ov_out_of_sync_print(mdev);
@@ -5167,7 +5216,7 @@ static struct asender_cmd asender_tbl[] = {
        [P_RECV_ACK]        = { sizeof(struct p_block_ack), got_BlockAck },
        [P_WRITE_ACK]       = { sizeof(struct p_block_ack), got_BlockAck },
        [P_RS_WRITE_ACK]    = { sizeof(struct p_block_ack), got_BlockAck },
-       [P_DISCARD_WRITE]   = { sizeof(struct p_block_ack), got_BlockAck },
+       [P_SUPERSEDED]   = { sizeof(struct p_block_ack), got_BlockAck },
        [P_NEG_ACK]         = { sizeof(struct p_block_ack), got_NegAck },
        [P_NEG_DREPLY]      = { sizeof(struct p_block_ack), got_NegDReply },
        [P_NEG_RS_DREPLY]   = { sizeof(struct p_block_ack), got_NegRSDReply },
@@ -5252,6 +5301,18 @@ int drbd_asender(struct drbd_thread *thi)
                        received += rv;
                        buf      += rv;
                } else if (rv == 0) {
+                       if (test_bit(DISCONNECT_SENT, &tconn->flags)) {
+                               long t;
+                               rcu_read_lock();
+                               t = rcu_dereference(tconn->net_conf)->ping_timeo * HZ/10;
+                               rcu_read_unlock();
+
+                               t = wait_event_timeout(tconn->ping_wait,
+                                                      tconn->cstate < C_WF_REPORT_PARAMS,
+                                                      t);
+                               if (t)
+                                       break;
+                       }
                        conn_err(tconn, "meta connection shut down by peer.\n");
                        goto reconnect;
                } else if (rv == -EAGAIN) {
@@ -5316,6 +5377,7 @@ int drbd_asender(struct drbd_thread *thi)
        if (0) {
 reconnect:
                conn_request_state(tconn, NS(conn, C_NETWORK_FAILURE), CS_HARD);
+               conn_md_sync(tconn);
        }
        if (0) {
 disconnect: