drivers/block/drbd/drbd_receiver.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3    drbd_receiver.c
   4
   5    This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
   6
   7    Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
   8    Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
   9    Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
  10
  11  */
  12
  13
  14 #include <linux/module.h>
  15
  16 #include <linux/uaccess.h>
  17 #include <net/sock.h>
  18
  19 #include <linux/drbd.h>
  20 #include <linux/fs.h>
  21 #include <linux/file.h>
  22 #include <linux/in.h>
  23 #include <linux/mm.h>
  24 #include <linux/memcontrol.h>
  25 #include <linux/mm_inline.h>
  26 #include <linux/slab.h>
  27 #include <uapi/linux/sched/types.h>
  28 #include <linux/sched/signal.h>
  29 #include <linux/pkt_sched.h>
  30 #define __KERNEL_SYSCALLS__
  31 #include <linux/unistd.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/random.h>
  34 #include <linux/string.h>
  35 #include <linux/scatterlist.h>
  36 #include <linux/part_stat.h>
  37 #include "drbd_int.h"
  38 #include "drbd_protocol.h"
  39 #include "drbd_req.h"
  40 #include "drbd_vli.h"
  41
  42 #define PRO_FEATURES (DRBD_FF_TRIM|DRBD_FF_THIN_RESYNC|DRBD_FF_WSAME|DRBD_FF_WZEROES)
  43
  44 struct packet_info {
  45         enum drbd_packet cmd;
  46         unsigned int size;
  47         unsigned int vnr;
  48         void *data;
  49 };
  50
  51 enum finish_epoch {
  52         FE_STILL_LIVE,
  53         FE_DESTROYED,
  54         FE_RECYCLED,
  55 };
  56
  57 static int drbd_do_features(struct drbd_connection *connection);
  58 static int drbd_do_auth(struct drbd_connection *connection);
  59 static int drbd_disconnected(struct drbd_peer_device *);
  60 static void conn_wait_active_ee_empty(struct drbd_connection *connection);
  61 static enum finish_epoch drbd_may_finish_epoch(struct drbd_connection *, struct drbd_epoch *, enum epoch_event);
  62 static int e_end_block(struct drbd_work *, int);
  63
  64
  65 #define GFP_TRY (__GFP_HIGHMEM | __GFP_NOWARN)
  66
  67 /*
  68  * some helper functions to deal with single linked page lists,
  69  * page->private being our "next" pointer.
  70  */
  71
  72 /* If at least n pages are linked at head, get n pages off.
  73  * Otherwise, don't modify head, and return NULL.
  74  * Locking is the responsibility of the caller.
  75  */
  76 static struct page *page_chain_del(struct page **head, int n)
  77 {
  78         struct page *page;
  79         struct page *tmp;
  80
  81         BUG_ON(!n);
  82         BUG_ON(!head);
  83
  84         page = *head;
  85
  86         if (!page)
  87                 return NULL;
  88
  89         while (page) {
  90                 tmp = page_chain_next(page);
  91                 if (--n == 0)
  92                         break; /* found sufficient pages */
  93                 if (tmp == NULL)
  94                         /* insufficient pages, don't use any of them. */
  95                         return NULL;
  96                 page = tmp;
  97         }
  98
  99         /* add end of list marker for the returned list */
 100         set_page_private(page, 0);
 101         /* actual return value, and adjustment of head */
 102         page = *head;
 103         *head = tmp;
 104         return page;
 105 }
 106
 107 /* may be used outside of locks to find the tail of a (usually short)
 108  * "private" page chain, before adding it back to a global chain head
 109  * with page_chain_add() under a spinlock. */
 110 static struct page *page_chain_tail(struct page *page, int *len)
 111 {
 112         struct page *tmp;
 113         int i = 1;
 114         while ((tmp = page_chain_next(page))) {
 115                 ++i;
 116                 page = tmp;
 117         }
 118         if (len)
 119                 *len = i;
 120         return page;
 121 }
 122
 123 static int page_chain_free(struct page *page)
 124 {
 125         struct page *tmp;
 126         int i = 0;
 127         page_chain_for_each_safe(page, tmp) {
 128                 put_page(page);
 129                 ++i;
 130         }
 131         return i;
 132 }
 133
 134 static void page_chain_add(struct page **head,
 135                 struct page *chain_first, struct page *chain_last)
 136 {
 137 #if 1
 138         struct page *tmp;
 139         tmp = page_chain_tail(chain_first, NULL);
 140         BUG_ON(tmp != chain_last);
 141 #endif
 142
 143         /* add chain to head */
 144         set_page_private(chain_last, (unsigned long)*head);
 145         *head = chain_first;
 146 }
 147
 148 static struct page *__drbd_alloc_pages(struct drbd_device *device,
 149                                        unsigned int number)
 150 {
 151         struct page *page = NULL;
 152         struct page *tmp = NULL;
 153         unsigned int i = 0;
 154
 155         /* Yes, testing drbd_pp_vacant outside the lock is racy.
 156          * So what. It saves a spin_lock. */
 157         if (drbd_pp_vacant >= number) {
 158                 spin_lock(&drbd_pp_lock);
 159                 page = page_chain_del(&drbd_pp_pool, number);
 160                 if (page)
 161                         drbd_pp_vacant -= number;
 162                 spin_unlock(&drbd_pp_lock);
 163                 if (page)
 164                         return page;
 165         }
 166
 167         /* GFP_TRY, because we must not cause arbitrary write-out: in a DRBD
 168          * "criss-cross" setup, that might cause write-out on some other DRBD,
 169          * which in turn might block on the other node at this very place.  */
 170         for (i = 0; i < number; i++) {
 171                 tmp = alloc_page(GFP_TRY);
 172                 if (!tmp)
 173                         break;
 174                 set_page_private(tmp, (unsigned long)page);
 175                 page = tmp;
 176         }
 177
 178         if (i == number)
 179                 return page;
 180
 181         /* Not enough pages immediately available this time.
 182          * No need to jump around here, drbd_alloc_pages will retry this
 183          * function "soon". */
 184         if (page) {
 185                 tmp = page_chain_tail(page, NULL);
 186                 spin_lock(&drbd_pp_lock);
 187                 page_chain_add(&drbd_pp_pool, page, tmp);
 188                 drbd_pp_vacant += i;
 189                 spin_unlock(&drbd_pp_lock);
 190         }
 191         return NULL;
 192 }
 193
 194 static void reclaim_finished_net_peer_reqs(struct drbd_device *device,
 195                                            struct list_head *to_be_freed)
 196 {
 197         struct drbd_peer_request *peer_req, *tmp;
 198
 199         /* The EEs are always appended to the end of the list. Since
 200            they are sent in order over the wire, they have to finish
 201            in order. As soon as we see the first not finished we can
 202            stop to examine the list... */
 203
 204         list_for_each_entry_safe(peer_req, tmp, &device->net_ee, w.list) {
 205                 if (drbd_peer_req_has_active_page(peer_req))
 206                         break;
 207                 list_move(&peer_req->w.list, to_be_freed);
 208         }
 209 }
 210
 211 static void drbd_reclaim_net_peer_reqs(struct drbd_device *device)
 212 {
 213         LIST_HEAD(reclaimed);
 214         struct drbd_peer_request *peer_req, *t;
 215
 216         spin_lock_irq(&device->resource->req_lock);
 217         reclaim_finished_net_peer_reqs(device, &reclaimed);
 218         spin_unlock_irq(&device->resource->req_lock);
 219         list_for_each_entry_safe(peer_req, t, &reclaimed, w.list)
 220                 drbd_free_net_peer_req(device, peer_req);
 221 }
 222
 223 static void conn_reclaim_net_peer_reqs(struct drbd_connection *connection)
 224 {
 225         struct drbd_peer_device *peer_device;
 226         int vnr;
 227
 228         rcu_read_lock();
 229         idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
 230                 struct drbd_device *device = peer_device->device;
 231                 if (!atomic_read(&device->pp_in_use_by_net))
 232                         continue;
 233
 234                 kref_get(&device->kref);
 235                 rcu_read_unlock();
 236                 drbd_reclaim_net_peer_reqs(device);
 237                 kref_put(&device->kref, drbd_destroy_device);
 238                 rcu_read_lock();
 239         }
 240         rcu_read_unlock();
 241 }
 242
 243 /**
 244  * drbd_alloc_pages() - Returns @number pages, retries forever (or until signalled)
 245  * @peer_device:        DRBD device.
 246  * @number:             number of pages requested
 247  * @retry:              whether to retry, if not enough pages are available right now
 248  *
 249  * Tries to allocate number pages, first from our own page pool, then from
 250  * the kernel.
 251  * Possibly retry until DRBD frees sufficient pages somewhere else.
 252  *
 253  * If this allocation would exceed the max_buffers setting, we throttle
 254  * allocation (schedule_timeout) to give the system some room to breathe.
 255  *
 256  * We do not use max-buffers as hard limit, because it could lead to
 257  * congestion and further to a distributed deadlock during online-verify or
 258  * (checksum based) resync, if the max-buffers, socket buffer sizes and
 259  * resync-rate settings are mis-configured.
 260  *
 261  * Returns a page chain linked via page->private.
 262  */
 263 struct page *drbd_alloc_pages(struct drbd_peer_device *peer_device, unsigned int number,
 264                               bool retry)
 265 {
 266         struct drbd_device *device = peer_device->device;
 267         struct page *page = NULL;
 268         struct net_conf *nc;
 269         DEFINE_WAIT(wait);
 270         unsigned int mxb;
 271
 272         rcu_read_lock();
 273         nc = rcu_dereference(peer_device->connection->net_conf);
 274         mxb = nc ? nc->max_buffers : 1000000;
 275         rcu_read_unlock();
 276
 277         if (atomic_read(&device->pp_in_use) < mxb)
 278                 page = __drbd_alloc_pages(device, number);
 279
 280         /* Try to keep the fast path fast, but occasionally we need
 281          * to reclaim the pages we lended to the network stack. */
 282         if (page && atomic_read(&device->pp_in_use_by_net) > 512)
 283                 drbd_reclaim_net_peer_reqs(device);
 284
 285         while (page == NULL) {
 286                 prepare_to_wait(&drbd_pp_wait, &wait, TASK_INTERRUPTIBLE);
 287
 288                 drbd_reclaim_net_peer_reqs(device);
 289
 290                 if (atomic_read(&device->pp_in_use) < mxb) {
 291                         page = __drbd_alloc_pages(device, number);
 292                         if (page)
 293                                 break;
 294                 }
 295
 296                 if (!retry)
 297                         break;
 298
 299                 if (signal_pending(current)) {
 300                         drbd_warn(device, "drbd_alloc_pages interrupted!\n");
 301                         break;
 302                 }
 303
 304                 if (schedule_timeout(HZ/10) == 0)
 305                         mxb = UINT_MAX;
 306         }
 307         finish_wait(&drbd_pp_wait, &wait);
 308
 309         if (page)
 310                 atomic_add(number, &device->pp_in_use);
 311         return page;
 312 }
 313
 314 /* Must not be used from irq, as that may deadlock: see drbd_alloc_pages.
 315  * Is also used from inside an other spin_lock_irq(&resource->req_lock);
 316  * Either links the page chain back to the global pool,
 317  * or returns all pages to the system. */
 318 static void drbd_free_pages(struct drbd_device *device, struct page *page, int is_net)
 319 {
 320         atomic_t *a = is_net ? &device->pp_in_use_by_net : &device->pp_in_use;
 321         int i;
 322
 323         if (page == NULL)
 324                 return;
 325
 326         if (drbd_pp_vacant > (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * drbd_minor_count)
 327                 i = page_chain_free(page);
 328         else {
 329                 struct page *tmp;
 330                 tmp = page_chain_tail(page, &i);
 331                 spin_lock(&drbd_pp_lock);
 332                 page_chain_add(&drbd_pp_pool, page, tmp);
 333                 drbd_pp_vacant += i;
 334                 spin_unlock(&drbd_pp_lock);
 335         }
 336         i = atomic_sub_return(i, a);
 337         if (i < 0)
 338                 drbd_warn(device, "ASSERTION FAILED: %s: %d < 0\n",
 339                         is_net ? "pp_in_use_by_net" : "pp_in_use", i);
 340         wake_up(&drbd_pp_wait);
 341 }
 342
 343 /*
 344 You need to hold the req_lock:
 345  _drbd_wait_ee_list_empty()
 346
 347 You must not have the req_lock:
 348  drbd_free_peer_req()
 349  drbd_alloc_peer_req()
 350  drbd_free_peer_reqs()
 351  drbd_ee_fix_bhs()
 352  drbd_finish_peer_reqs()
 353  drbd_clear_done_ee()
 354  drbd_wait_ee_list_empty()
 355 */
 356
 357 /* normal: payload_size == request size (bi_size)
 358  * w_same: payload_size == logical_block_size
 359  * trim: payload_size == 0 */
 360 struct drbd_peer_request *
 361 drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
 362                     unsigned int request_size, unsigned int payload_size, gfp_t gfp_mask) __must_hold(local)
 363 {
 364         struct drbd_device *device = peer_device->device;
 365         struct drbd_peer_request *peer_req;
 366         struct page *page = NULL;
 367         unsigned nr_pages = (payload_size + PAGE_SIZE -1) >> PAGE_SHIFT;
 368
 369         if (drbd_insert_fault(device, DRBD_FAULT_AL_EE))
 370                 return NULL;
 371
 372         peer_req = mempool_alloc(&drbd_ee_mempool, gfp_mask & ~__GFP_HIGHMEM);
 373         if (!peer_req) {
 374                 if (!(gfp_mask & __GFP_NOWARN))
 375                         drbd_err(device, "%s: allocation failed\n", __func__);
 376                 return NULL;
 377         }
 378
 379         if (nr_pages) {
 380                 page = drbd_alloc_pages(peer_device, nr_pages,
 381                                         gfpflags_allow_blocking(gfp_mask));
 382                 if (!page)
 383                         goto fail;
 384         }
 385
 386         memset(peer_req, 0, sizeof(*peer_req));
 387         INIT_LIST_HEAD(&peer_req->w.list);
 388         drbd_clear_interval(&peer_req->i);
 389         peer_req->i.size = request_size;
 390         peer_req->i.sector = sector;
 391         peer_req->submit_jif = jiffies;
 392         peer_req->peer_device = peer_device;
 393         peer_req->pages = page;
 394         /*
 395          * The block_id is opaque to the receiver.  It is not endianness
 396          * converted, and sent back to the sender unchanged.
 397          */
 398         peer_req->block_id = id;
 399
 400         return peer_req;
 401
 402  fail:
 403         mempool_free(peer_req, &drbd_ee_mempool);
 404         return NULL;
 405 }
 406
 407 void __drbd_free_peer_req(struct drbd_device *device, struct drbd_peer_request *peer_req,
 408                        int is_net)
 409 {
 410         might_sleep();
 411         if (peer_req->flags & EE_HAS_DIGEST)
 412                 kfree(peer_req->digest);
 413         drbd_free_pages(device, peer_req->pages, is_net);
 414         D_ASSERT(device, atomic_read(&peer_req->pending_bios) == 0);
 415         D_ASSERT(device, drbd_interval_empty(&peer_req->i));
 416         if (!expect(!(peer_req->flags & EE_CALL_AL_COMPLETE_IO))) {
 417                 peer_req->flags &= ~EE_CALL_AL_COMPLETE_IO;
 418                 drbd_al_complete_io(device, &peer_req->i);
 419         }
 420         mempool_free(peer_req, &drbd_ee_mempool);
 421 }
 422
 423 int drbd_free_peer_reqs(struct drbd_device *device, struct list_head *list)
 424 {
 425         LIST_HEAD(work_list);
 426         struct drbd_peer_request *peer_req, *t;
 427         int count = 0;
 428         int is_net = list == &device->net_ee;
 429
 430         spin_lock_irq(&device->resource->req_lock);
 431         list_splice_init(list, &work_list);
 432         spin_unlock_irq(&device->resource->req_lock);
 433
 434         list_for_each_entry_safe(peer_req, t, &work_list, w.list) {
 435                 __drbd_free_peer_req(device, peer_req, is_net);
 436                 count++;
 437         }
 438         return count;
 439 }
 440
 441 /*
 442  * See also comments in _req_mod(,BARRIER_ACKED) and receive_Barrier.
 443  */
 444 static int drbd_finish_peer_reqs(struct drbd_device *device)
 445 {
 446         LIST_HEAD(work_list);
 447         LIST_HEAD(reclaimed);
 448         struct drbd_peer_request *peer_req, *t;
 449         int err = 0;
 450
 451         spin_lock_irq(&device->resource->req_lock);
 452         reclaim_finished_net_peer_reqs(device, &reclaimed);
 453         list_splice_init(&device->done_ee, &work_list);
 454         spin_unlock_irq(&device->resource->req_lock);
 455
 456         list_for_each_entry_safe(peer_req, t, &reclaimed, w.list)
 457                 drbd_free_net_peer_req(device, peer_req);
 458
 459         /* possible callbacks here:
 460          * e_end_block, and e_end_resync_block, e_send_superseded.
 461          * all ignore the last argument.
 462          */
 463         list_for_each_entry_safe(peer_req, t, &work_list, w.list) {
 464                 int err2;
 465
 466                 /* list_del not necessary, next/prev members not touched */
 467                 err2 = peer_req->w.cb(&peer_req->w, !!err);
 468                 if (!err)
 469                         err = err2;
 470                 drbd_free_peer_req(device, peer_req);
 471         }
 472         wake_up(&device->ee_wait);
 473
 474         return err;
 475 }
 476
 477 static void _drbd_wait_ee_list_empty(struct drbd_device *device,
 478                                      struct list_head *head)
 479 {
 480         DEFINE_WAIT(wait);
 481
 482         /* avoids spin_lock/unlock
 483          * and calling prepare_to_wait in the fast path */
 484         while (!list_empty(head)) {
 485                 prepare_to_wait(&device->ee_wait, &wait, TASK_UNINTERRUPTIBLE);
 486                 spin_unlock_irq(&device->resource->req_lock);
 487                 io_schedule();
 488                 finish_wait(&device->ee_wait, &wait);
 489                 spin_lock_irq(&device->resource->req_lock);
 490         }
 491 }
 492
 493 static void drbd_wait_ee_list_empty(struct drbd_device *device,
 494                                     struct list_head *head)
 495 {
 496         spin_lock_irq(&device->resource->req_lock);
 497         _drbd_wait_ee_list_empty(device, head);
 498         spin_unlock_irq(&device->resource->req_lock);
 499 }
 500
 501 static int drbd_recv_short(struct socket *sock, void *buf, size_t size, int flags)
 502 {
 503         struct kvec iov = {
 504                 .iov_base = buf,
 505                 .iov_len = size,
 506         };
 507         struct msghdr msg = {
 508                 .msg_flags = (flags ? flags : MSG_WAITALL | MSG_NOSIGNAL)
 509         };
 510         iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, size);
 511         return sock_recvmsg(sock, &msg, msg.msg_flags);
 512 }
 513
 514 static int drbd_recv(struct drbd_connection *connection, void *buf, size_t size)
 515 {
 516         int rv;
 517
 518         rv = drbd_recv_short(connection->data.socket, buf, size, 0);
 519
 520         if (rv < 0) {
 521                 if (rv == -ECONNRESET)
 522                         drbd_info(connection, "sock was reset by peer\n");
 523                 else if (rv != -ERESTARTSYS)
 524                         drbd_err(connection, "sock_recvmsg returned %d\n", rv);
 525         } else if (rv == 0) {
 526                 if (test_bit(DISCONNECT_SENT, &connection->flags)) {
 527                         long t;
 528                         rcu_read_lock();
 529                         t = rcu_dereference(connection->net_conf)->ping_timeo * HZ/10;
 530                         rcu_read_unlock();
 531
 532                         t = wait_event_timeout(connection->ping_wait, connection->cstate < C_WF_REPORT_PARAMS, t);
 533
 534                         if (t)
 535                                 goto out;
 536                 }
 537                 drbd_info(connection, "sock was shut down by peer\n");
 538         }
 539
 540         if (rv != size)
 541                 conn_request_state(connection, NS(conn, C_BROKEN_PIPE), CS_HARD);
 542
 543 out:
 544         return rv;
 545 }
 546
 547 static int drbd_recv_all(struct drbd_connection *connection, void *buf, size_t size)
 548 {
 549         int err;
 550
 551         err = drbd_recv(connection, buf, size);
 552         if (err != size) {
 553                 if (err >= 0)
 554                         err = -EIO;
 555         } else
 556                 err = 0;
 557         return err;
 558 }
 559
 560 static int drbd_recv_all_warn(struct drbd_connection *connection, void *buf, size_t size)
 561 {
 562         int err;
 563
 564         err = drbd_recv_all(connection, buf, size);
 565         if (err && !signal_pending(current))
 566                 drbd_warn(connection, "short read (expected size %d)\n", (int)size);
 567         return err;
 568 }
 569
 570 /* quoting tcp(7):
 571  *   On individual connections, the socket buffer size must be set prior to the
 572  *   listen(2) or connect(2) calls in order to have it take effect.
 573  * This is our wrapper to do so.
 574  */
 575 static void drbd_setbufsize(struct socket *sock, unsigned int snd,
 576                 unsigned int rcv)
 577 {
 578         /* open coded SO_SNDBUF, SO_RCVBUF */
 579         if (snd) {
 580                 sock->sk->sk_sndbuf = snd;
 581                 sock->sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
 582         }
 583         if (rcv) {
 584                 sock->sk->sk_rcvbuf = rcv;
 585                 sock->sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
 586         }
 587 }
 588
 589 static struct socket *drbd_try_connect(struct drbd_connection *connection)
 590 {
 591         const char *what;
 592         struct socket *sock;
 593         struct sockaddr_in6 src_in6;
 594         struct sockaddr_in6 peer_in6;
 595         struct net_conf *nc;
 596         int err, peer_addr_len, my_addr_len;
 597         int sndbuf_size, rcvbuf_size, connect_int;
 598         int disconnect_on_error = 1;
 599
 600         rcu_read_lock();
 601         nc = rcu_dereference(connection->net_conf);
 602         if (!nc) {
 603                 rcu_read_unlock();
 604                 return NULL;
 605         }
 606         sndbuf_size = nc->sndbuf_size;
 607         rcvbuf_size = nc->rcvbuf_size;
 608         connect_int = nc->connect_int;
 609         rcu_read_unlock();
 610
 611         my_addr_len = min_t(int, connection->my_addr_len, sizeof(src_in6));
 612         memcpy(&src_in6, &connection->my_addr, my_addr_len);
 613
 614         if (((struct sockaddr *)&connection->my_addr)->sa_family == AF_INET6)
 615                 src_in6.sin6_port = 0;
 616         else
 617                 ((struct sockaddr_in *)&src_in6)->sin_port = 0; /* AF_INET & AF_SCI */
 618
 619         peer_addr_len = min_t(int, connection->peer_addr_len, sizeof(src_in6));
 620         memcpy(&peer_in6, &connection->peer_addr, peer_addr_len);
 621
 622         what = "sock_create_kern";
 623         err = sock_create_kern(&init_net, ((struct sockaddr *)&src_in6)->sa_family,
 624                                SOCK_STREAM, IPPROTO_TCP, &sock);
 625         if (err < 0) {
 626                 sock = NULL;
 627                 goto out;
 628         }
 629
 630         sock->sk->sk_rcvtimeo =
 631         sock->sk->sk_sndtimeo = connect_int * HZ;
 632         drbd_setbufsize(sock, sndbuf_size, rcvbuf_size);
 633
 634        /* explicitly bind to the configured IP as source IP
 635         *  for the outgoing connections.
 636         *  This is needed for multihomed hosts and to be
 637         *  able to use lo: interfaces for drbd.
 638         * Make sure to use 0 as port number, so linux selects
 639         *  a free one dynamically.
 640         */
 641         what = "bind before connect";
 642         err = sock->ops->bind(sock, (struct sockaddr *) &src_in6, my_addr_len);
 643         if (err < 0)
 644                 goto out;
 645
 646         /* connect may fail, peer not yet available.
 647          * stay C_WF_CONNECTION, don't go Disconnecting! */
 648         disconnect_on_error = 0;
 649         what = "connect";
 650         err = sock->ops->connect(sock, (struct sockaddr *) &peer_in6, peer_addr_len, 0);
 651
 652 out:
 653         if (err < 0) {
 654                 if (sock) {
 655                         sock_release(sock);
 656                         sock = NULL;
 657                 }
 658                 switch (-err) {
 659                         /* timeout, busy, signal pending */
 660                 case ETIMEDOUT: case EAGAIN: case EINPROGRESS:
 661                 case EINTR: case ERESTARTSYS:
 662                         /* peer not (yet) available, network problem */
 663                 case ECONNREFUSED: case ENETUNREACH:
 664                 case EHOSTDOWN:    case EHOSTUNREACH:
 665                         disconnect_on_error = 0;
 666                         break;
 667                 default:
 668                         drbd_err(connection, "%s failed, err = %d\n", what, err);
 669                 }
 670                 if (disconnect_on_error)
 671                         conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_HARD);
 672         }
 673
 674         return sock;
 675 }
 676
 677 struct accept_wait_data {
 678         struct drbd_connection *connection;
 679         struct socket *s_listen;
 680         struct completion door_bell;
 681         void (*original_sk_state_change)(struct sock *sk);
 682
 683 };
 684
 685 static void drbd_incoming_connection(struct sock *sk)
 686 {
 687         struct accept_wait_data *ad = sk->sk_user_data;
 688         void (*state_change)(struct sock *sk);
 689
 690         state_change = ad->original_sk_state_change;
 691         if (sk->sk_state == TCP_ESTABLISHED)
 692                 complete(&ad->door_bell);
 693         state_change(sk);
 694 }
 695
 696 static int prepare_listen_socket(struct drbd_connection *connection, struct accept_wait_data *ad)
 697 {
 698         int err, sndbuf_size, rcvbuf_size, my_addr_len;
 699         struct sockaddr_in6 my_addr;
 700         struct socket *s_listen;
 701         struct net_conf *nc;
 702         const char *what;
 703
 704         rcu_read_lock();
 705         nc = rcu_dereference(connection->net_conf);
 706         if (!nc) {
 707                 rcu_read_unlock();
 708                 return -EIO;
 709         }
 710         sndbuf_size = nc->sndbuf_size;
 711         rcvbuf_size = nc->rcvbuf_size;
 712         rcu_read_unlock();
 713
 714         my_addr_len = min_t(int, connection->my_addr_len, sizeof(struct sockaddr_in6));
 715         memcpy(&my_addr, &connection->my_addr, my_addr_len);
 716
 717         what = "sock_create_kern";
 718         err = sock_create_kern(&init_net, ((struct sockaddr *)&my_addr)->sa_family,
 719                                SOCK_STREAM, IPPROTO_TCP, &s_listen);
 720         if (err) {
 721                 s_listen = NULL;
 722                 goto out;
 723         }
 724
 725         s_listen->sk->sk_reuse = SK_CAN_REUSE; /* SO_REUSEADDR */
 726         drbd_setbufsize(s_listen, sndbuf_size, rcvbuf_size);
 727
 728         what = "bind before listen";
 729         err = s_listen->ops->bind(s_listen, (struct sockaddr *)&my_addr, my_addr_len);
 730         if (err < 0)
 731                 goto out;
 732
 733         ad->s_listen = s_listen;
 734         write_lock_bh(&s_listen->sk->sk_callback_lock);
 735         ad->original_sk_state_change = s_listen->sk->sk_state_change;
 736         s_listen->sk->sk_state_change = drbd_incoming_connection;
 737         s_listen->sk->sk_user_data = ad;
 738         write_unlock_bh(&s_listen->sk->sk_callback_lock);
 739
 740         what = "listen";
 741         err = s_listen->ops->listen(s_listen, 5);
 742         if (err < 0)
 743                 goto out;
 744
 745         return 0;
 746 out:
 747         if (s_listen)
 748                 sock_release(s_listen);
 749         if (err < 0) {
 750                 if (err != -EAGAIN && err != -EINTR && err != -ERESTARTSYS) {
 751                         drbd_err(connection, "%s failed, err = %d\n", what, err);
 752                         conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_HARD);
 753                 }
 754         }
 755
 756         return -EIO;
 757 }
 758
 759 static void unregister_state_change(struct sock *sk, struct accept_wait_data *ad)
 760 {
 761         write_lock_bh(&sk->sk_callback_lock);
 762         sk->sk_state_change = ad->original_sk_state_change;
 763         sk->sk_user_data = NULL;
 764         write_unlock_bh(&sk->sk_callback_lock);
 765 }
 766
 767 static struct socket *drbd_wait_for_connect(struct drbd_connection *connection, struct accept_wait_data *ad)
 768 {
 769         int timeo, connect_int, err = 0;
 770         struct socket *s_estab = NULL;
 771         struct net_conf *nc;
 772
 773         rcu_read_lock();
 774         nc = rcu_dereference(connection->net_conf);
 775         if (!nc) {
 776                 rcu_read_unlock();
 777                 return NULL;
 778         }
 779         connect_int = nc->connect_int;
 780         rcu_read_unlock();
 781
 782         timeo = connect_int * HZ;
 783         /* 28.5% random jitter */
 784         timeo += (prandom_u32() & 1) ? timeo / 7 : -timeo / 7;
 785
 786         err = wait_for_completion_interruptible_timeout(&ad->door_bell, timeo);
 787         if (err <= 0)
 788                 return NULL;
 789
 790         err = kernel_accept(ad->s_listen, &s_estab, 0);
 791         if (err < 0) {
 792                 if (err != -EAGAIN && err != -EINTR && err != -ERESTARTSYS) {
 793                         drbd_err(connection, "accept failed, err = %d\n", err);
 794                         conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_HARD);
 795                 }
 796         }
 797
 798         if (s_estab)
 799                 unregister_state_change(s_estab->sk, ad);
 800
 801         return s_estab;
 802 }
 803
 804 static int decode_header(struct drbd_connection *, void *, struct packet_info *);
 805
 806 static int send_first_packet(struct drbd_connection *connection, struct drbd_socket *sock,
 807                              enum drbd_packet cmd)
 808 {
 809         if (!conn_prepare_command(connection, sock))
 810                 return -EIO;
 811         return conn_send_command(connection, sock, cmd, 0, NULL, 0);
 812 }
 813
 814 static int receive_first_packet(struct drbd_connection *connection, struct socket *sock)
 815 {
 816         unsigned int header_size = drbd_header_size(connection);
 817         struct packet_info pi;
 818         struct net_conf *nc;
 819         int err;
 820
 821         rcu_read_lock();
 822         nc = rcu_dereference(connection->net_conf);
 823         if (!nc) {
 824                 rcu_read_unlock();
 825                 return -EIO;
 826         }
 827         sock->sk->sk_rcvtimeo = nc->ping_timeo * 4 * HZ / 10;
 828         rcu_read_unlock();
 829
 830         err = drbd_recv_short(sock, connection->data.rbuf, header_size, 0);
 831         if (err != header_size) {
 832                 if (err >= 0)
 833                         err = -EIO;
 834                 return err;
 835         }
 836         err = decode_header(connection, connection->data.rbuf, &pi);
 837         if (err)
 838                 return err;
 839         return pi.cmd;
 840 }
 841
 842 /**
 843  * drbd_socket_okay() - Free the socket if its connection is not okay
 844  * @sock:       pointer to the pointer to the socket.
 845  */
 846 static bool drbd_socket_okay(struct socket **sock)
 847 {
 848         int rr;
 849         char tb[4];
 850
 851         if (!*sock)
 852                 return false;
 853
 854         rr = drbd_recv_short(*sock, tb, 4, MSG_DONTWAIT | MSG_PEEK);
 855
 856         if (rr > 0 || rr == -EAGAIN) {
 857                 return true;
 858         } else {
 859                 sock_release(*sock);
 860                 *sock = NULL;
 861                 return false;
 862         }
 863 }
 864
 865 static bool connection_established(struct drbd_connection *connection,
 866                                    struct socket **sock1,
 867                                    struct socket **sock2)
 868 {
 869         struct net_conf *nc;
 870         int timeout;
 871         bool ok;
 872
 873         if (!*sock1 || !*sock2)
 874                 return false;
 875
 876         rcu_read_lock();
 877         nc = rcu_dereference(connection->net_conf);
 878         timeout = (nc->sock_check_timeo ?: nc->ping_timeo) * HZ / 10;
 879         rcu_read_unlock();
 880         schedule_timeout_interruptible(timeout);
 881
 882         ok = drbd_socket_okay(sock1);
 883         ok = drbd_socket_okay(sock2) && ok;
 884
 885         return ok;
 886 }
 887
 888 /* Gets called if a connection is established, or if a new minor gets created
 889    in a connection */
 890 int drbd_connected(struct drbd_peer_device *peer_device)
 891 {
 892         struct drbd_device *device = peer_device->device;
 893         int err;
 894
 895         atomic_set(&device->packet_seq, 0);
 896         device->peer_seq = 0;
 897
 898         device->state_mutex = peer_device->connection->agreed_pro_version < 100 ?
 899                 &peer_device->connection->cstate_mutex :
 900                 &device->own_state_mutex;
 901
 902         err = drbd_send_sync_param(peer_device);
 903         if (!err)
 904                 err = drbd_send_sizes(peer_device, 0, 0);
 905         if (!err)
 906                 err = drbd_send_uuids(peer_device);
 907         if (!err)
 908                 err = drbd_send_current_state(peer_device);
 909         clear_bit(USE_DEGR_WFC_T, &device->flags);
 910         clear_bit(RESIZE_PENDING, &device->flags);
 911         atomic_set(&device->ap_in_flight, 0);
 912         mod_timer(&device->request_timer, jiffies + HZ); /* just start it here. */
 913         return err;
 914 }
 915
 916 /*
 917  * return values:
 918  *   1 yes, we have a valid connection
 919  *   0 oops, did not work out, please try again
 920  *  -1 peer talks different language,
 921  *     no point in trying again, please go standalone.
 922  *  -2 We do not have a network config...
 923  */
 924 static int conn_connect(struct drbd_connection *connection)
 925 {
 926         struct drbd_socket sock, msock;
 927         struct drbd_peer_device *peer_device;
 928         struct net_conf *nc;
 929         int vnr, timeout, h;
 930         bool discard_my_data, ok;
 931         enum drbd_state_rv rv;
 932         struct accept_wait_data ad = {
 933                 .connection = connection,
 934                 .door_bell = COMPLETION_INITIALIZER_ONSTACK(ad.door_bell),
 935         };
 936
 937         clear_bit(DISCONNECT_SENT, &connection->flags);
 938         if (conn_request_state(connection, NS(conn, C_WF_CONNECTION), CS_VERBOSE) < SS_SUCCESS)
 939                 return -2;
 940
 941         mutex_init(&sock.mutex);
 942         sock.sbuf = connection->data.sbuf;
 943         sock.rbuf = connection->data.rbuf;
 944         sock.socket = NULL;
 945         mutex_init(&msock.mutex);
 946         msock.sbuf = connection->meta.sbuf;
 947         msock.rbuf = connection->meta.rbuf;
 948         msock.socket = NULL;
 949
 950         /* Assume that the peer only understands protocol 80 until we know better.  */
 951         connection->agreed_pro_version = 80;
 952
 953         if (prepare_listen_socket(connection, &ad))
 954                 return 0;
 955
 956         do {
 957                 struct socket *s;
 958
 959                 s = drbd_try_connect(connection);
 960                 if (s) {
 961                         if (!sock.socket) {
 962                                 sock.socket = s;
 963                                 send_first_packet(connection, &sock, P_INITIAL_DATA);
 964                         } else if (!msock.socket) {
 965                                 clear_bit(RESOLVE_CONFLICTS, &connection->flags);
 966                                 msock.socket = s;
 967                                 send_first_packet(connection, &msock, P_INITIAL_META);
 968                         } else {
 969                                 drbd_err(connection, "Logic error in conn_connect()\n");
 970                                 goto out_release_sockets;
 971                         }
 972                 }
 973
 974                 if (connection_established(connection, &sock.socket, &msock.socket))
 975                         break;
 976
 977 retry:
 978                 s = drbd_wait_for_connect(connection, &ad);
 979                 if (s) {
 980                         int fp = receive_first_packet(connection, s);
 981                         drbd_socket_okay(&sock.socket);
 982                         drbd_socket_okay(&msock.socket);
 983                         switch (fp) {
 984                         case P_INITIAL_DATA:
 985                                 if (sock.socket) {
 986                                         drbd_warn(connection, "initial packet S crossed\n");
 987                                         sock_release(sock.socket);
 988                                         sock.socket = s;
 989                                         goto randomize;
 990                                 }
 991                                 sock.socket = s;
 992                                 break;
 993                         case P_INITIAL_META:
 994                                 set_bit(RESOLVE_CONFLICTS, &connection->flags);
 995                                 if (msock.socket) {
 996                                         drbd_warn(connection, "initial packet M crossed\n");
 997                                         sock_release(msock.socket);
 998                                         msock.socket = s;
 999                                         goto randomize;
1000                                 }
1001                                 msock.socket = s;
1002                                 break;
1003                         default:
1004                                 drbd_warn(connection, "Error receiving initial packet\n");
1005                                 sock_release(s);
1006 randomize:
1007                                 if (prandom_u32() & 1)
1008                                         goto retry;
1009                         }
1010                 }
1011
1012                 if (connection->cstate <= C_DISCONNECTING)
1013                         goto out_release_sockets;
1014                 if (signal_pending(current)) {
1015                         flush_signals(current);
1016                         smp_rmb();
1017                         if (get_t_state(&connection->receiver) == EXITING)
1018                                 goto out_release_sockets;
1019                 }
1020
1021                 ok = connection_established(connection, &sock.socket, &msock.socket);
1022         } while (!ok);
1023
1024         if (ad.s_listen)
1025                 sock_release(ad.s_listen);
1026
1027         sock.socket->sk->sk_reuse = SK_CAN_REUSE; /* SO_REUSEADDR */
1028         msock.socket->sk->sk_reuse = SK_CAN_REUSE; /* SO_REUSEADDR */
1029
1030         sock.socket->sk->sk_allocation = GFP_NOIO;
1031         msock.socket->sk->sk_allocation = GFP_NOIO;
1032
1033         sock.socket->sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
1034         msock.socket->sk->sk_priority = TC_PRIO_INTERACTIVE;
1035
1036         /* NOT YET ...
1037          * sock.socket->sk->sk_sndtimeo = connection->net_conf->timeout*HZ/10;
1038          * sock.socket->sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
1039          * first set it to the P_CONNECTION_FEATURES timeout,
1040          * which we set to 4x the configured ping_timeout. */
1041         rcu_read_lock();
1042         nc = rcu_dereference(connection->net_conf);
1043
1044         sock.socket->sk->sk_sndtimeo =
1045         sock.socket->sk->sk_rcvtimeo = nc->ping_timeo*4*HZ/10;
1046
1047         msock.socket->sk->sk_rcvtimeo = nc->ping_int*HZ;
1048         timeout = nc->timeout * HZ / 10;
1049         discard_my_data = nc->discard_my_data;
1050         rcu_read_unlock();
1051
1052         msock.socket->sk->sk_sndtimeo = timeout;
1053
1054         /* we don't want delays.
1055          * we use TCP_CORK where appropriate, though */
1056         tcp_sock_set_nodelay(sock.socket->sk);
1057         tcp_sock_set_nodelay(msock.socket->sk);
1058
1059         connection->data.socket = sock.socket;
1060         connection->meta.socket = msock.socket;
1061         connection->last_received = jiffies;
1062
1063         h = drbd_do_features(connection);
1064         if (h <= 0)
1065                 return h;
1066
1067         if (connection->cram_hmac_tfm) {
1068                 /* drbd_request_state(device, NS(conn, WFAuth)); */
1069                 switch (drbd_do_auth(connection)) {
1070                 case -1:
1071                         drbd_err(connection, "Authentication of peer failed\n");
1072                         return -1;
1073                 case 0:
1074                         drbd_err(connection, "Authentication of peer failed, trying again.\n");
1075                         return 0;
1076                 }
1077         }
1078
1079         connection->data.socket->sk->sk_sndtimeo = timeout;
1080         connection->data.socket->sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
1081
1082         if (drbd_send_protocol(connection) == -EOPNOTSUPP)
1083                 return -1;
1084
1085         /* Prevent a race between resync-handshake and
1086          * being promoted to Primary.
1087          *
1088          * Grab and release the state mutex, so we know that any current
1089          * drbd_set_role() is finished, and any incoming drbd_set_role
1090          * will see the STATE_SENT flag, and wait for it to be cleared.
1091          */
1092         idr_for_each_entry(&connection->peer_devices, peer_device, vnr)
1093                 mutex_lock(peer_device->device->state_mutex);
1094
1095         /* avoid a race with conn_request_state( C_DISCONNECTING ) */
1096         spin_lock_irq(&connection->resource->req_lock);
1097         set_bit(STATE_SENT, &connection->flags);
1098         spin_unlock_irq(&connection->resource->req_lock);
1099
1100         idr_for_each_entry(&connection->peer_devices, peer_device, vnr)
1101                 mutex_unlock(peer_device->device->state_mutex);
1102
1103         rcu_read_lock();
1104         idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
1105                 struct drbd_device *device = peer_device->device;
1106                 kref_get(&device->kref);
1107                 rcu_read_unlock();
1108
1109                 if (discard_my_data)
1110                         set_bit(DISCARD_MY_DATA, &device->flags);
1111                 else
1112                         clear_bit(DISCARD_MY_DATA, &device->flags);
1113
1114                 drbd_connected(peer_device);
1115                 kref_put(&device->kref, drbd_destroy_device);
1116                 rcu_read_lock();
1117         }
1118         rcu_read_unlock();
1119
1120         rv = conn_request_state(connection, NS(conn, C_WF_REPORT_PARAMS), CS_VERBOSE);
1121         if (rv < SS_SUCCESS || connection->cstate != C_WF_REPORT_PARAMS) {
1122                 clear_bit(STATE_SENT, &connection->flags);
1123                 return 0;
1124         }
1125
1126         drbd_thread_start(&connection->ack_receiver);
1127         /* opencoded create_singlethread_workqueue(),
1128          * to be able to use format string arguments */
1129         connection->ack_sender =
1130                 alloc_ordered_workqueue("drbd_as_%s", WQ_MEM_RECLAIM, connection->resource->name);
1131         if (!connection->ack_sender) {
1132                 drbd_err(connection, "Failed to create workqueue ack_sender\n");
1133                 return 0;
1134         }
1135
1136         mutex_lock(&connection->resource->conf_update);
1137         /* The discard_my_data flag is a single-shot modifier to the next
1138          * connection attempt, the handshake of which is now well underway.
1139          * No need for rcu style copying of the whole struct
1140          * just to clear a single value. */
1141         connection->net_conf->discard_my_data = 0;
1142         mutex_unlock(&connection->resource->conf_update);
1143
1144         return h;
1145
1146 out_release_sockets:
1147         if (ad.s_listen)
1148                 sock_release(ad.s_listen);
1149         if (sock.socket)
1150                 sock_release(sock.socket);
1151         if (msock.socket)
1152                 sock_release(msock.socket);
1153         return -1;
1154 }
1155
1156 static int decode_header(struct drbd_connection *connection, void *header, struct packet_info *pi)
1157 {
1158         unsigned int header_size = drbd_header_size(connection);
1159
1160         if (header_size == sizeof(struct p_header100) &&
1161             *(__be32 *)header == cpu_to_be32(DRBD_MAGIC_100)) {
1162                 struct p_header100 *h = header;
1163                 if (h->pad != 0) {
1164                         drbd_err(connection, "Header padding is not zero\n");
1165                         return -EINVAL;
1166                 }
1167                 pi->vnr = be16_to_cpu(h->volume);
1168                 pi->cmd = be16_to_cpu(h->command);
1169                 pi->size = be32_to_cpu(h->length);
1170         } else if (header_size == sizeof(struct p_header95) &&
1171                    *(__be16 *)header == cpu_to_be16(DRBD_MAGIC_BIG)) {
1172                 struct p_header95 *h = header;
1173                 pi->cmd = be16_to_cpu(h->command);
1174                 pi->size = be32_to_cpu(h->length);
1175                 pi->vnr = 0;
1176         } else if (header_size == sizeof(struct p_header80) &&
1177                    *(__be32 *)header == cpu_to_be32(DRBD_MAGIC)) {
1178                 struct p_header80 *h = header;
1179                 pi->cmd = be16_to_cpu(h->command);
1180                 pi->size = be16_to_cpu(h->length);
1181                 pi->vnr = 0;
1182         } else {
1183                 drbd_err(connection, "Wrong magic value 0x%08x in protocol version %d\n",
1184                          be32_to_cpu(*(__be32 *)header),
1185                          connection->agreed_pro_version);
1186                 return -EINVAL;
1187         }
1188         pi->data = header + header_size;
1189         return 0;
1190 }
1191
1192 static void drbd_unplug_all_devices(struct drbd_connection *connection)
1193 {
1194         if (current->plug == &connection->receiver_plug) {
1195                 blk_finish_plug(&connection->receiver_plug);
1196                 blk_start_plug(&connection->receiver_plug);
1197         } /* else: maybe just schedule() ?? */
1198 }
1199
1200 static int drbd_recv_header(struct drbd_connection *connection, struct packet_info *pi)
1201 {
1202         void *buffer = connection->data.rbuf;
1203         int err;
1204
1205         err = drbd_recv_all_warn(connection, buffer, drbd_header_size(connection));
1206         if (err)
1207                 return err;
1208
1209         err = decode_header(connection, buffer, pi);
1210         connection->last_received = jiffies;
1211
1212         return err;
1213 }
1214
1215 static int drbd_recv_header_maybe_unplug(struct drbd_connection *connection, struct packet_info *pi)
1216 {
1217         void *buffer = connection->data.rbuf;
1218         unsigned int size = drbd_header_size(connection);
1219         int err;
1220
1221         err = drbd_recv_short(connection->data.socket, buffer, size, MSG_NOSIGNAL|MSG_DONTWAIT);
1222         if (err != size) {
1223                 /* If we have nothing in the receive buffer now, to reduce
1224                  * application latency, try to drain the backend queues as
1225                  * quickly as possible, and let remote TCP know what we have
1226                  * received so far. */
1227                 if (err == -EAGAIN) {
1228                         tcp_sock_set_quickack(connection->data.socket->sk, 2);
1229                         drbd_unplug_all_devices(connection);
1230                 }
1231                 if (err > 0) {
1232                         buffer += err;
1233                         size -= err;
1234                 }
1235                 err = drbd_recv_all_warn(connection, buffer, size);
1236                 if (err)
1237                         return err;
1238         }
1239
1240         err = decode_header(connection, connection->data.rbuf, pi);
1241         connection->last_received = jiffies;
1242
1243         return err;
1244 }
1245 /* This is blkdev_issue_flush, but asynchronous.
1246  * We want to submit to all component volumes in parallel,
1247  * then wait for all completions.
1248  */
1249 struct issue_flush_context {
1250         atomic_t pending;
1251         int error;
1252         struct completion done;
1253 };
1254 struct one_flush_context {
1255         struct drbd_device *device;
1256         struct issue_flush_context *ctx;
1257 };
1258
1259 static void one_flush_endio(struct bio *bio)
1260 {
1261         struct one_flush_context *octx = bio->bi_private;
1262         struct drbd_device *device = octx->device;
1263         struct issue_flush_context *ctx = octx->ctx;
1264
1265         if (bio->bi_status) {
1266                 ctx->error = blk_status_to_errno(bio->bi_status);
1267                 drbd_info(device, "local disk FLUSH FAILED with status %d\n", bio->bi_status);
1268         }
1269         kfree(octx);
1270         bio_put(bio);
1271
1272         clear_bit(FLUSH_PENDING, &device->flags);
1273         put_ldev(device);
1274         kref_put(&device->kref, drbd_destroy_device);
1275
1276         if (atomic_dec_and_test(&ctx->pending))
1277                 complete(&ctx->done);
1278 }
1279
1280 static void submit_one_flush(struct drbd_device *device, struct issue_flush_context *ctx)
1281 {
1282         struct bio *bio = bio_alloc(GFP_NOIO, 0);
1283         struct one_flush_context *octx = kmalloc(sizeof(*octx), GFP_NOIO);
1284         if (!bio || !octx) {
1285                 drbd_warn(device, "Could not allocate a bio, CANNOT ISSUE FLUSH\n");
1286                 /* FIXME: what else can I do now?  disconnecting or detaching
1287                  * really does not help to improve the state of the world, either.
1288                  */
1289                 kfree(octx);
1290                 if (bio)
1291                         bio_put(bio);
1292
1293                 ctx->error = -ENOMEM;
1294                 put_ldev(device);
1295                 kref_put(&device->kref, drbd_destroy_device);
1296                 return;
1297         }
1298
1299         octx->device = device;
1300         octx->ctx = ctx;
1301         bio_set_dev(bio, device->ldev->backing_bdev);
1302         bio->bi_private = octx;
1303         bio->bi_end_io = one_flush_endio;
1304         bio->bi_opf = REQ_OP_FLUSH | REQ_PREFLUSH;
1305
1306         device->flush_jif = jiffies;
1307         set_bit(FLUSH_PENDING, &device->flags);
1308         atomic_inc(&ctx->pending);
1309         submit_bio(bio);
1310 }
1311
1312 static void drbd_flush(struct drbd_connection *connection)
1313 {
1314         if (connection->resource->write_ordering >= WO_BDEV_FLUSH) {
1315                 struct drbd_peer_device *peer_device;
1316                 struct issue_flush_context ctx;
1317                 int vnr;
1318
1319                 atomic_set(&ctx.pending, 1);
1320                 ctx.error = 0;
1321                 init_completion(&ctx.done);
1322
1323                 rcu_read_lock();
1324                 idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
1325                         struct drbd_device *device = peer_device->device;
1326
1327                         if (!get_ldev(device))
1328                                 continue;
1329                         kref_get(&device->kref);
1330                         rcu_read_unlock();
1331
1332                         submit_one_flush(device, &ctx);
1333
1334                         rcu_read_lock();
1335                 }
1336                 rcu_read_unlock();
1337
1338                 /* Do we want to add a timeout,
1339                  * if disk-timeout is set? */
1340                 if (!atomic_dec_and_test(&ctx.pending))
1341                         wait_for_completion(&ctx.done);
1342
1343                 if (ctx.error) {
1344                         /* would rather check on EOPNOTSUPP, but that is not reliable.
1345                          * don't try again for ANY return value != 0
1346                          * if (rv == -EOPNOTSUPP) */
1347                         /* Any error is already reported by bio_endio callback. */
1348                         drbd_bump_write_ordering(connection->resource, NULL, WO_DRAIN_IO);
1349                 }
1350         }
1351 }
1352
1353 /**
1354  * drbd_may_finish_epoch() - Applies an epoch_event to the epoch's state, eventually finishes it.
1355  * @connection: DRBD connection.
1356  * @epoch:      Epoch object.
1357  * @ev:         Epoch event.
1358  */
1359 static enum finish_epoch drbd_may_finish_epoch(struct drbd_connection *connection,
1360                                                struct drbd_epoch *epoch,
1361                                                enum epoch_event ev)
1362 {
1363         int epoch_size;
1364         struct drbd_epoch *next_epoch;
1365         enum finish_epoch rv = FE_STILL_LIVE;
1366
1367         spin_lock(&connection->epoch_lock);
1368         do {
1369                 next_epoch = NULL;
1370
1371                 epoch_size = atomic_read(&epoch->epoch_size);
1372
1373                 switch (ev & ~EV_CLEANUP) {
1374                 case EV_PUT:
1375                         atomic_dec(&epoch->active);
1376                         break;
1377                 case EV_GOT_BARRIER_NR:
1378                         set_bit(DE_HAVE_BARRIER_NUMBER, &epoch->flags);
1379                         break;
1380                 case EV_BECAME_LAST:
1381                         /* nothing to do*/
1382                         break;
1383                 }
1384
1385                 if (epoch_size != 0 &&
1386                     atomic_read(&epoch->active) == 0 &&
1387                     (test_bit(DE_HAVE_BARRIER_NUMBER, &epoch->flags) || ev & EV_CLEANUP)) {
1388                         if (!(ev & EV_CLEANUP)) {
1389                                 spin_unlock(&connection->epoch_lock);
1390                                 drbd_send_b_ack(epoch->connection, epoch->barrier_nr, epoch_size);
1391                                 spin_lock(&connection->epoch_lock);
1392                         }
1393 #if 0
1394                         /* FIXME: dec unacked on connection, once we have
1395                          * something to count pending connection packets in. */
1396                         if (test_bit(DE_HAVE_BARRIER_NUMBER, &epoch->flags))
1397                                 dec_unacked(epoch->connection);
1398 #endif
1399
1400                         if (connection->current_epoch != epoch) {
1401                                 next_epoch = list_entry(epoch->list.next, struct drbd_epoch, list);
1402                                 list_del(&epoch->list);
1403                                 ev = EV_BECAME_LAST | (ev & EV_CLEANUP);
1404                                 connection->epochs--;
1405                                 kfree(epoch);
1406
1407                                 if (rv == FE_STILL_LIVE)
1408                                         rv = FE_DESTROYED;
1409                         } else {
1410                                 epoch->flags = 0;
1411                                 atomic_set(&epoch->epoch_size, 0);
1412                                 /* atomic_set(&epoch->active, 0); is already zero */
1413                                 if (rv == FE_STILL_LIVE)
1414                                         rv = FE_RECYCLED;
1415                         }
1416                 }
1417
1418                 if (!next_epoch)
1419                         break;
1420
1421                 epoch = next_epoch;
1422         } while (1);
1423
1424         spin_unlock(&connection->epoch_lock);
1425
1426         return rv;
1427 }
1428
1429 static enum write_ordering_e
1430 max_allowed_wo(struct drbd_backing_dev *bdev, enum write_ordering_e wo)
1431 {
1432         struct disk_conf *dc;
1433
1434         dc = rcu_dereference(bdev->disk_conf);
1435
1436         if (wo == WO_BDEV_FLUSH && !dc->disk_flushes)
1437                 wo = WO_DRAIN_IO;
1438         if (wo == WO_DRAIN_IO && !dc->disk_drain)
1439                 wo = WO_NONE;
1440
1441         return wo;
1442 }
1443
1444 /*
1445  * drbd_bump_write_ordering() - Fall back to an other write ordering method
1446  * @wo:         Write ordering method to try.
1447  */
1448 void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backing_dev *bdev,
1449                               enum write_ordering_e wo)
1450 {
1451         struct drbd_device *device;
1452         enum write_ordering_e pwo;
1453         int vnr;
1454         static char *write_ordering_str[] = {
1455                 [WO_NONE] = "none",
1456                 [WO_DRAIN_IO] = "drain",
1457                 [WO_BDEV_FLUSH] = "flush",
1458         };
1459
1460         pwo = resource->write_ordering;
1461         if (wo != WO_BDEV_FLUSH)
1462                 wo = min(pwo, wo);
1463         rcu_read_lock();
1464         idr_for_each_entry(&resource->devices, device, vnr) {
1465                 if (get_ldev(device)) {
1466                         wo = max_allowed_wo(device->ldev, wo);
1467                         if (device->ldev == bdev)
1468                                 bdev = NULL;
1469                         put_ldev(device);
1470                 }
1471         }
1472
1473         if (bdev)
1474                 wo = max_allowed_wo(bdev, wo);
1475
1476         rcu_read_unlock();
1477
1478         resource->write_ordering = wo;
1479         if (pwo != resource->write_ordering || wo == WO_BDEV_FLUSH)
1480                 drbd_info(resource, "Method to ensure write ordering: %s\n", write_ordering_str[resource->write_ordering]);
1481 }
1482
1483 /*
1484  * Mapping "discard" to ZEROOUT with UNMAP does not work for us:
1485  * Drivers have to "announce" q->limits.max_write_zeroes_sectors, or it
1486  * will directly go to fallback mode, submitting normal writes, and
1487  * never even try to UNMAP.
1488  *
1489  * And dm-thin does not do this (yet), mostly because in general it has
1490  * to assume that "skip_block_zeroing" is set.  See also:
1491  * https://www.mail-archive.com/dm-devel%40redhat.com/msg07965.html
1492  * https://www.redhat.com/archives/dm-devel/2018-January/msg00271.html
1493  *
1494  * We *may* ignore the discard-zeroes-data setting, if so configured.
1495  *
1496  * Assumption is that this "discard_zeroes_data=0" is only because the backend
1497  * may ignore partial unaligned discards.
1498  *
1499  * LVM/DM thin as of at least
1500  *   LVM version:     2.02.115(2)-RHEL7 (2015-01-28)
1501  *   Library version: 1.02.93-RHEL7 (2015-01-28)
1502  *   Driver version:  4.29.0
1503  * still behaves this way.
1504  *
1505  * For unaligned (wrt. alignment and granularity) or too small discards,
1506  * we zero-out the initial (and/or) trailing unaligned partial chunks,
1507  * but discard all the aligned full chunks.
1508  *
1509  * At least for LVM/DM thin, with skip_block_zeroing=false,
1510  * the result is effectively "discard_zeroes_data=1".
1511  */
1512 /* flags: EE_TRIM|EE_ZEROOUT */
1513 int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, unsigned int nr_sectors, int flags)
1514 {
1515         struct block_device *bdev = device->ldev->backing_bdev;
1516         struct request_queue *q = bdev_get_queue(bdev);
1517         sector_t tmp, nr;
1518         unsigned int max_discard_sectors, granularity;
1519         int alignment;
1520         int err = 0;
1521
1522         if ((flags & EE_ZEROOUT) || !(flags & EE_TRIM))
1523                 goto zero_out;
1524
1525         /* Zero-sector (unknown) and one-sector granularities are the same.  */
1526         granularity = max(q->limits.discard_granularity >> 9, 1U);
1527         alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
1528
1529         max_discard_sectors = min(q->limits.max_discard_sectors, (1U << 22));
1530         max_discard_sectors -= max_discard_sectors % granularity;
1531         if (unlikely(!max_discard_sectors))
1532                 goto zero_out;
1533
1534         if (nr_sectors < granularity)
1535                 goto zero_out;
1536
1537         tmp = start;
1538         if (sector_div(tmp, granularity) != alignment) {
1539                 if (nr_sectors < 2*granularity)
1540                         goto zero_out;
1541                 /* start + gran - (start + gran - align) % gran */
1542                 tmp = start + granularity - alignment;
1543                 tmp = start + granularity - sector_div(tmp, granularity);
1544
1545                 nr = tmp - start;
1546                 /* don't flag BLKDEV_ZERO_NOUNMAP, we don't know how many
1547                  * layers are below us, some may have smaller granularity */
1548                 err |= blkdev_issue_zeroout(bdev, start, nr, GFP_NOIO, 0);
1549                 nr_sectors -= nr;
1550                 start = tmp;
1551         }
1552         while (nr_sectors >= max_discard_sectors) {
1553                 err |= blkdev_issue_discard(bdev, start, max_discard_sectors, GFP_NOIO, 0);
1554                 nr_sectors -= max_discard_sectors;
1555                 start += max_discard_sectors;
1556         }
1557         if (nr_sectors) {
1558                 /* max_discard_sectors is unsigned int (and a multiple of
1559                  * granularity, we made sure of that above already);
1560                  * nr is < max_discard_sectors;
1561                  * I don't need sector_div here, even though nr is sector_t */
1562                 nr = nr_sectors;
1563                 nr -= (unsigned int)nr % granularity;
1564                 if (nr) {
1565                         err |= blkdev_issue_discard(bdev, start, nr, GFP_NOIO, 0);
1566                         nr_sectors -= nr;
1567                         start += nr;
1568                 }
1569         }
1570  zero_out:
1571         if (nr_sectors) {
1572                 err |= blkdev_issue_zeroout(bdev, start, nr_sectors, GFP_NOIO,
1573                                 (flags & EE_TRIM) ? 0 : BLKDEV_ZERO_NOUNMAP);
1574         }
1575         return err != 0;
1576 }
1577
1578 static bool can_do_reliable_discards(struct drbd_device *device)
1579 {
1580         struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev);
1581         struct disk_conf *dc;
1582         bool can_do;
1583
1584         if (!blk_queue_discard(q))
1585                 return false;
1586
1587         rcu_read_lock();
1588         dc = rcu_dereference(device->ldev->disk_conf);
1589         can_do = dc->discard_zeroes_if_aligned;
1590         rcu_read_unlock();
1591         return can_do;
1592 }
1593
1594 static void drbd_issue_peer_discard_or_zero_out(struct drbd_device *device, struct drbd_peer_request *peer_req)
1595 {
1596         /* If the backend cannot discard, or does not guarantee
1597          * read-back zeroes in discarded ranges, we fall back to
1598          * zero-out.  Unless configuration specifically requested
1599          * otherwise. */
1600         if (!can_do_reliable_discards(device))
1601                 peer_req->flags |= EE_ZEROOUT;
1602
1603         if (drbd_issue_discard_or_zero_out(device, peer_req->i.sector,
1604             peer_req->i.size >> 9, peer_req->flags & (EE_ZEROOUT|EE_TRIM)))
1605                 peer_req->flags |= EE_WAS_ERROR;
1606         drbd_endio_write_sec_final(peer_req);
1607 }
1608
1609 static void drbd_issue_peer_wsame(struct drbd_device *device,
1610                                   struct drbd_peer_request *peer_req)
1611 {
1612         struct block_device *bdev = device->ldev->backing_bdev;
1613         sector_t s = peer_req->i.sector;
1614         sector_t nr = peer_req->i.size >> 9;
1615         if (blkdev_issue_write_same(bdev, s, nr, GFP_NOIO, peer_req->pages))
1616                 peer_req->flags |= EE_WAS_ERROR;
1617         drbd_endio_write_sec_final(peer_req);
1618 }
1619
1620
1621 /*
1622  * drbd_submit_peer_request()
1623  * @device:     DRBD device.
1624  * @peer_req:   peer request
1625  *
1626  * May spread the pages to multiple bios,
1627  * depending on bio_add_page restrictions.
1628  *
1629  * Returns 0 if all bios have been submitted,
1630  * -ENOMEM if we could not allocate enough bios,
1631  * -ENOSPC (any better suggestion?) if we have not been able to bio_add_page a
1632  *  single page to an empty bio (which should never happen and likely indicates
1633  *  that the lower level IO stack is in some way broken). This has been observed
1634  *  on certain Xen deployments.
1635  */
1636 /* TODO allocate from our own bio_set. */
1637 int drbd_submit_peer_request(struct drbd_device *device,
1638                              struct drbd_peer_request *peer_req,
1639                              const unsigned op, const unsigned op_flags,
1640                              const int fault_type)
1641 {
1642         struct bio *bios = NULL;
1643         struct bio *bio;
1644         struct page *page = peer_req->pages;
1645         sector_t sector = peer_req->i.sector;
1646         unsigned data_size = peer_req->i.size;
1647         unsigned n_bios = 0;
1648         unsigned nr_pages = (data_size + PAGE_SIZE -1) >> PAGE_SHIFT;
1649         int err = -ENOMEM;
1650
1651         /* TRIM/DISCARD: for now, always use the helper function
1652          * blkdev_issue_zeroout(..., discard=true).
1653          * It's synchronous, but it does the right thing wrt. bio splitting.
1654          * Correctness first, performance later.  Next step is to code an
1655          * asynchronous variant of the same.
1656          */
1657         if (peer_req->flags & (EE_TRIM|EE_WRITE_SAME|EE_ZEROOUT)) {
1658                 /* wait for all pending IO completions, before we start
1659                  * zeroing things out. */
1660                 conn_wait_active_ee_empty(peer_req->peer_device->connection);
1661                 /* add it to the active list now,
1662                  * so we can find it to present it in debugfs */
1663                 peer_req->submit_jif = jiffies;
1664                 peer_req->flags |= EE_SUBMITTED;
1665
1666                 /* If this was a resync request from receive_rs_deallocated(),
1667                  * it is already on the sync_ee list */
1668                 if (list_empty(&peer_req->w.list)) {
1669                         spin_lock_irq(&device->resource->req_lock);
1670                         list_add_tail(&peer_req->w.list, &device->active_ee);
1671                         spin_unlock_irq(&device->resource->req_lock);
1672                 }
1673
1674                 if (peer_req->flags & (EE_TRIM|EE_ZEROOUT))
1675                         drbd_issue_peer_discard_or_zero_out(device, peer_req);
1676                 else /* EE_WRITE_SAME */
1677                         drbd_issue_peer_wsame(device, peer_req);
1678                 return 0;
1679         }
1680
1681         /* In most cases, we will only need one bio.  But in case the lower
1682          * level restrictions happen to be different at this offset on this
1683          * side than those of the sending peer, we may need to submit the
1684          * request in more than one bio.
1685          *
1686          * Plain bio_alloc is good enough here, this is no DRBD internally
1687          * generated bio, but a bio allocated on behalf of the peer.
1688          */
1689 next_bio:
1690         bio = bio_alloc(GFP_NOIO, nr_pages);
1691         if (!bio) {
1692                 drbd_err(device, "submit_ee: Allocation of a bio failed (nr_pages=%u)\n", nr_pages);
1693                 goto fail;
1694         }
1695         /* > peer_req->i.sector, unless this is the first bio */
1696         bio->bi_iter.bi_sector = sector;
1697         bio_set_dev(bio, device->ldev->backing_bdev);
1698         bio_set_op_attrs(bio, op, op_flags);
1699         bio->bi_private = peer_req;
1700         bio->bi_end_io = drbd_peer_request_endio;
1701
1702         bio->bi_next = bios;
1703         bios = bio;
1704         ++n_bios;
1705
1706         page_chain_for_each(page) {
1707                 unsigned len = min_t(unsigned, data_size, PAGE_SIZE);
1708                 if (!bio_add_page(bio, page, len, 0))
1709                         goto next_bio;
1710                 data_size -= len;
1711                 sector += len >> 9;
1712                 --nr_pages;
1713         }
1714         D_ASSERT(device, data_size == 0);
1715         D_ASSERT(device, page == NULL);
1716
1717         atomic_set(&peer_req->pending_bios, n_bios);
1718         /* for debugfs: update timestamp, mark as submitted */
1719         peer_req->submit_jif = jiffies;
1720         peer_req->flags |= EE_SUBMITTED;
1721         do {
1722                 bio = bios;
1723                 bios = bios->bi_next;
1724                 bio->bi_next = NULL;
1725
1726                 drbd_submit_bio_noacct(device, fault_type, bio);
1727         } while (bios);
1728         return 0;
1729
1730 fail:
1731         while (bios) {
1732                 bio = bios;
1733                 bios = bios->bi_next;
1734                 bio_put(bio);
1735         }
1736         return err;
1737 }
1738
1739 static void drbd_remove_epoch_entry_interval(struct drbd_device *device,
1740                                              struct drbd_peer_request *peer_req)
1741 {
1742         struct drbd_interval *i = &peer_req->i;
1743
1744         drbd_remove_interval(&device->write_requests, i);
1745         drbd_clear_interval(i);
1746
1747         /* Wake up any processes waiting for this peer request to complete.  */
1748         if (i->waiting)
1749                 wake_up(&device->misc_wait);
1750 }
1751
1752 static void conn_wait_active_ee_empty(struct drbd_connection *connection)
1753 {
1754         struct drbd_peer_device *peer_device;
1755         int vnr;
1756
1757         rcu_read_lock();
1758         idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
1759                 struct drbd_device *device = peer_device->device;
1760
1761                 kref_get(&device->kref);
1762                 rcu_read_unlock();
1763                 drbd_wait_ee_list_empty(device, &device->active_ee);
1764                 kref_put(&device->kref, drbd_destroy_device);
1765                 rcu_read_lock();
1766         }
1767         rcu_read_unlock();
1768 }
1769
1770 static int receive_Barrier(struct drbd_connection *connection, struct packet_info *pi)
1771 {
1772         int rv;
1773         struct p_barrier *p = pi->data;
1774         struct drbd_epoch *epoch;
1775
1776         /* FIXME these are unacked on connection,
1777          * not a specific (peer)device.
1778          */
1779         connection->current_epoch->barrier_nr = p->barrier;
1780         connection->current_epoch->connection = connection;
1781         rv = drbd_may_finish_epoch(connection, connection->current_epoch, EV_GOT_BARRIER_NR);
1782
1783         /* P_BARRIER_ACK may imply that the corresponding extent is dropped from
1784          * the activity log, which means it would not be resynced in case the
1785          * R_PRIMARY crashes now.
1786          * Therefore we must send the barrier_ack after the barrier request was
1787          * completed. */
1788         switch (connection->resource->write_ordering) {
1789         case WO_NONE:
1790                 if (rv == FE_RECYCLED)
1791                         return 0;
1792
1793                 /* receiver context, in the writeout path of the other node.
1794                  * avoid potential distributed deadlock */
1795                 epoch = kmalloc(sizeof(struct drbd_epoch), GFP_NOIO);
1796                 if (epoch)
1797                         break;
1798                 else
1799                         drbd_warn(connection, "Allocation of an epoch failed, slowing down\n");
1800                 fallthrough;
1801
1802         case WO_BDEV_FLUSH:
1803         case WO_DRAIN_IO:
1804                 conn_wait_active_ee_empty(connection);
1805                 drbd_flush(connection);
1806
1807                 if (atomic_read(&connection->current_epoch->epoch_size)) {
1808                         epoch = kmalloc(sizeof(struct drbd_epoch), GFP_NOIO);
1809                         if (epoch)
1810                                 break;
1811                 }
1812
1813                 return 0;
1814         default:
1815                 drbd_err(connection, "Strangeness in connection->write_ordering %d\n",
1816                          connection->resource->write_ordering);
1817                 return -EIO;
1818         }
1819
1820         epoch->flags = 0;
1821         atomic_set(&epoch->epoch_size, 0);
1822         atomic_set(&epoch->active, 0);
1823
1824         spin_lock(&connection->epoch_lock);
1825         if (atomic_read(&connection->current_epoch->epoch_size)) {
1826                 list_add(&epoch->list, &connection->current_epoch->list);
1827                 connection->current_epoch = epoch;
1828                 connection->epochs++;
1829         } else {
1830                 /* The current_epoch got recycled while we allocated this one... */
1831                 kfree(epoch);
1832         }
1833         spin_unlock(&connection->epoch_lock);
1834
1835         return 0;
1836 }
1837
1838 /* quick wrapper in case payload size != request_size (write same) */
1839 static void drbd_csum_ee_size(struct crypto_shash *h,
1840                               struct drbd_peer_request *r, void *d,
1841                               unsigned int payload_size)
1842 {
1843         unsigned int tmp = r->i.size;
1844         r->i.size = payload_size;
1845         drbd_csum_ee(h, r, d);
1846         r->i.size = tmp;
1847 }
1848
1849 /* used from receive_RSDataReply (recv_resync_read)
1850  * and from receive_Data.
1851  * data_size: actual payload ("data in")
1852  *      for normal writes that is bi_size.
1853  *      for discards, that is zero.
1854  *      for write same, it is logical_block_size.
1855  * both trim and write same have the bi_size ("data len to be affected")
1856  * as extra argument in the packet header.
1857  */
1858 static struct drbd_peer_request *
1859 read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
1860               struct packet_info *pi) __must_hold(local)
1861 {
1862         struct drbd_device *device = peer_device->device;
1863         const sector_t capacity = get_capacity(device->vdisk);
1864         struct drbd_peer_request *peer_req;
1865         struct page *page;
1866         int digest_size, err;
1867         unsigned int data_size = pi->size, ds;
1868         void *dig_in = peer_device->connection->int_dig_in;
1869         void *dig_vv = peer_device->connection->int_dig_vv;
1870         unsigned long *data;
1871         struct p_trim *trim = (pi->cmd == P_TRIM) ? pi->data : NULL;
1872         struct p_trim *zeroes = (pi->cmd == P_ZEROES) ? pi->data : NULL;
1873         struct p_trim *wsame = (pi->cmd == P_WSAME) ? pi->data : NULL;
1874
1875         digest_size = 0;
1876         if (!trim && peer_device->connection->peer_integrity_tfm) {
1877                 digest_size = crypto_shash_digestsize(peer_device->connection->peer_integrity_tfm);
1878                 /*
1879                  * FIXME: Receive the incoming digest into the receive buffer
1880                  *        here, together with its struct p_data?
1881                  */
1882                 err = drbd_recv_all_warn(peer_device->connection, dig_in, digest_size);
1883                 if (err)
1884                         return NULL;
1885                 data_size -= digest_size;
1886         }
1887
1888         /* assume request_size == data_size, but special case trim and wsame. */
1889         ds = data_size;
1890         if (trim) {
1891                 if (!expect(data_size == 0))
1892                         return NULL;
1893                 ds = be32_to_cpu(trim->size);
1894         } else if (zeroes) {
1895                 if (!expect(data_size == 0))
1896                         return NULL;
1897                 ds = be32_to_cpu(zeroes->size);
1898         } else if (wsame) {
1899                 if (data_size != queue_logical_block_size(device->rq_queue)) {
1900                         drbd_err(peer_device, "data size (%u) != drbd logical block size (%u)\n",
1901                                 data_size, queue_logical_block_size(device->rq_queue));
1902                         return NULL;
1903                 }
1904                 if (data_size != bdev_logical_block_size(device->ldev->backing_bdev)) {
1905                         drbd_err(peer_device, "data size (%u) != backend logical block size (%u)\n",
1906                                 data_size, bdev_logical_block_size(device->ldev->backing_bdev));
1907                         return NULL;
1908                 }
1909                 ds = be32_to_cpu(wsame->size);
1910         }
1911
1912         if (!expect(IS_ALIGNED(ds, 512)))
1913                 return NULL;
1914         if (trim || wsame || zeroes) {
1915                 if (!expect(ds <= (DRBD_MAX_BBIO_SECTORS << 9)))
1916                         return NULL;
1917         } else if (!expect(ds <= DRBD_MAX_BIO_SIZE))
1918                 return NULL;
1919
1920         /* even though we trust out peer,
1921          * we sometimes have to double check. */
1922         if (sector + (ds>>9) > capacity) {
1923                 drbd_err(device, "request from peer beyond end of local disk: "
1924                         "capacity: %llus < sector: %llus + size: %u\n",
1925                         (unsigned long long)capacity,
1926                         (unsigned long long)sector, ds);
1927                 return NULL;
1928         }
1929
1930         /* GFP_NOIO, because we must not cause arbitrary write-out: in a DRBD
1931          * "criss-cross" setup, that might cause write-out on some other DRBD,
1932          * which in turn might block on the other node at this very place.  */
1933         peer_req = drbd_alloc_peer_req(peer_device, id, sector, ds, data_size, GFP_NOIO);
1934         if (!peer_req)
1935                 return NULL;
1936
1937         peer_req->flags |= EE_WRITE;
1938         if (trim) {
1939                 peer_req->flags |= EE_TRIM;
1940                 return peer_req;
1941         }
1942         if (zeroes) {
1943                 peer_req->flags |= EE_ZEROOUT;
1944                 return peer_req;
1945         }
1946         if (wsame)
1947                 peer_req->flags |= EE_WRITE_SAME;
1948
1949         /* receive payload size bytes into page chain */
1950         ds = data_size;
1951         page = peer_req->pages;
1952         page_chain_for_each(page) {
1953                 unsigned len = min_t(int, ds, PAGE_SIZE);
1954                 data = kmap(page);
1955                 err = drbd_recv_all_warn(peer_device->connection, data, len);
1956                 if (drbd_insert_fault(device, DRBD_FAULT_RECEIVE)) {
1957                         drbd_err(device, "Fault injection: Corrupting data on receive\n");
1958                         data[0] = data[0] ^ (unsigned long)-1;
1959                 }
1960                 kunmap(page);
1961                 if (err) {
1962                         drbd_free_peer_req(device, peer_req);
1963                         return NULL;
1964                 }
1965                 ds -= len;
1966         }
1967
1968         if (digest_size) {
1969                 drbd_csum_ee_size(peer_device->connection->peer_integrity_tfm, peer_req, dig_vv, data_size);
1970                 if (memcmp(dig_in, dig_vv, digest_size)) {
1971                         drbd_err(device, "Digest integrity check FAILED: %llus +%u\n",
1972                                 (unsigned long long)sector, data_size);
1973                         drbd_free_peer_req(device, peer_req);
1974                         return NULL;
1975                 }
1976         }
1977         device->recv_cnt += data_size >> 9;
1978         return peer_req;
1979 }
1980
1981 /* drbd_drain_block() just takes a data block
1982  * out of the socket input buffer, and discards it.
1983  */
1984 static int drbd_drain_block(struct drbd_peer_device *peer_device, int data_size)
1985 {
1986         struct page *page;
1987         int err = 0;
1988         void *data;
1989
1990         if (!data_size)
1991                 return 0;
1992
1993         page = drbd_alloc_pages(peer_device, 1, 1);
1994
1995         data = kmap(page);
1996         while (data_size) {
1997                 unsigned int len = min_t(int, data_size, PAGE_SIZE);
1998
1999                 err = drbd_recv_all_warn(peer_device->connection, data, len);
2000                 if (err)
2001                         break;
2002                 data_size -= len;
2003         }
2004         kunmap(page);
2005         drbd_free_pages(peer_device->device, page, 0);
2006         return err;
2007 }
2008
2009 static int recv_dless_read(struct drbd_peer_device *peer_device, struct drbd_request *req,
2010                            sector_t sector, int data_size)
2011 {
2012         struct bio_vec bvec;
2013         struct bvec_iter iter;
2014         struct bio *bio;
2015         int digest_size, err, expect;
2016         void *dig_in = peer_device->connection->int_dig_in;
2017         void *dig_vv = peer_device->connection->int_dig_vv;
2018
2019         digest_size = 0;
2020         if (peer_device->connection->peer_integrity_tfm) {
2021                 digest_size = crypto_shash_digestsize(peer_device->connection->peer_integrity_tfm);
2022                 err = drbd_recv_all_warn(peer_device->connection, dig_in, digest_size);
2023                 if (err)
2024                         return err;
2025                 data_size -= digest_size;
2026         }
2027
2028         /* optimistically update recv_cnt.  if receiving fails below,
2029          * we disconnect anyways, and counters will be reset. */
2030         peer_device->device->recv_cnt += data_size>>9;
2031
2032         bio = req->master_bio;
2033         D_ASSERT(peer_device->device, sector == bio->bi_iter.bi_sector);
2034
2035         bio_for_each_segment(bvec, bio, iter) {
2036                 void *mapped = kmap(bvec.bv_page) + bvec.bv_offset;
2037                 expect = min_t(int, data_size, bvec.bv_len);
2038                 err = drbd_recv_all_warn(peer_device->connection, mapped, expect);
2039                 kunmap(bvec.bv_page);
2040                 if (err)
2041                         return err;
2042                 data_size -= expect;
2043         }
2044
2045         if (digest_size) {
2046                 drbd_csum_bio(peer_device->connection->peer_integrity_tfm, bio, dig_vv);
2047                 if (memcmp(dig_in, dig_vv, digest_size)) {
2048                         drbd_err(peer_device, "Digest integrity check FAILED. Broken NICs?\n");
2049                         return -EINVAL;
2050                 }
2051         }
2052
2053         D_ASSERT(peer_device->device, data_size == 0);
2054         return 0;
2055 }
2056
2057 /*
2058  * e_end_resync_block() is called in ack_sender context via
2059  * drbd_finish_peer_reqs().
2060  */
2061 static int e_end_resync_block(struct drbd_work *w, int unused)
2062 {
2063         struct drbd_peer_request *peer_req =
2064                 container_of(w, struct drbd_peer_request, w);
2065         struct drbd_peer_device *peer_device = peer_req->peer_device;
2066         struct drbd_device *device = peer_device->device;
2067         sector_t sector = peer_req->i.sector;
2068         int err;
2069
2070         D_ASSERT(device, drbd_interval_empty(&peer_req->i));
2071
2072         if (likely((peer_req->flags & EE_WAS_ERROR) == 0)) {
2073                 drbd_set_in_sync(device, sector, peer_req->i.size);
2074                 err = drbd_send_ack(peer_device, P_RS_WRITE_ACK, peer_req);
2075         } else {
2076                 /* Record failure to sync */
2077                 drbd_rs_failed_io(device, sector, peer_req->i.size);
2078
2079                 err  = drbd_send_ack(peer_device, P_NEG_ACK, peer_req);
2080         }
2081         dec_unacked(device);
2082
2083         return err;
2084 }
2085
2086 static int recv_resync_read(struct drbd_peer_device *peer_device, sector_t sector,
2087                             struct packet_info *pi) __releases(local)
2088 {
2089         struct drbd_device *device = peer_device->device;
2090         struct drbd_peer_request *peer_req;
2091
2092         peer_req = read_in_block(peer_device, ID_SYNCER, sector, pi);
2093         if (!peer_req)
2094                 goto fail;
2095
2096         dec_rs_pending(device);
2097
2098         inc_unacked(device);
2099         /* corresponding dec_unacked() in e_end_resync_block()
2100          * respective _drbd_clear_done_ee */
2101
2102         peer_req->w.cb = e_end_resync_block;
2103         peer_req->submit_jif = jiffies;
2104
2105         spin_lock_irq(&device->resource->req_lock);
2106         list_add_tail(&peer_req->w.list, &device->sync_ee);
2107         spin_unlock_irq(&device->resource->req_lock);
2108
2109         atomic_add(pi->size >> 9, &device->rs_sect_ev);
2110         if (drbd_submit_peer_request(device, peer_req, REQ_OP_WRITE, 0,
2111                                      DRBD_FAULT_RS_WR) == 0)
2112                 return 0;
2113
2114         /* don't care for the reason here */
2115         drbd_err(device, "submit failed, triggering re-connect\n");
2116         spin_lock_irq(&device->resource->req_lock);
2117         list_del(&peer_req->w.list);
2118         spin_unlock_irq(&device->resource->req_lock);
2119
2120         drbd_free_peer_req(device, peer_req);
2121 fail:
2122         put_ldev(device);
2123         return -EIO;
2124 }
2125
2126 static struct drbd_request *
2127 find_request(struct drbd_device *device, struct rb_root *root, u64 id,
2128              sector_t sector, bool missing_ok, const char *func)
2129 {
2130         struct drbd_request *req;
2131
2132         /* Request object according to our peer */
2133         req = (struct drbd_request *)(unsigned long)id;
2134         if (drbd_contains_interval(root, sector, &req->i) && req->i.local)
2135                 return req;
2136         if (!missing_ok) {
2137                 drbd_err(device, "%s: failed to find request 0x%lx, sector %llus\n", func,
2138                         (unsigned long)id, (unsigned long long)sector);
2139         }
2140         return NULL;
2141 }
2142
2143 static int receive_DataReply(struct drbd_connection *connection, struct packet_info *pi)
2144 {
2145         struct drbd_peer_device *peer_device;
2146         struct drbd_device *device;
2147         struct drbd_request *req;
2148         sector_t sector;
2149         int err;
2150         struct p_data *p = pi->data;
2151
2152         peer_device = conn_peer_device(connection, pi->vnr);
2153         if (!peer_device)
2154                 return -EIO;
2155         device = peer_device->device;
2156
2157         sector = be64_to_cpu(p->sector);
2158
2159         spin_lock_irq(&device->resource->req_lock);
2160         req = find_request(device, &device->read_requests, p->block_id, sector, false, __func__);
2161         spin_unlock_irq(&device->resource->req_lock);
2162         if (unlikely(!req))
2163                 return -EIO;
2164
2165         /* hlist_del(&req->collision) is done in _req_may_be_done, to avoid
2166          * special casing it there for the various failure cases.
2167          * still no race with drbd_fail_pending_reads */
2168         err = recv_dless_read(peer_device, req, sector, pi->size);
2169         if (!err)
2170                 req_mod(req, DATA_RECEIVED);
2171         /* else: nothing. handled from drbd_disconnect...
2172          * I don't think we may complete this just yet
2173          * in case we are "on-disconnect: freeze" */
2174
2175         return err;
2176 }
2177
2178 static int receive_RSDataReply(struct drbd_connection *connection, struct packet_info *pi)
2179 {
2180         struct drbd_peer_device *peer_device;
2181         struct drbd_device *device;
2182         sector_t sector;
2183         int err;
2184         struct p_data *p = pi->data;
2185
2186         peer_device = conn_peer_device(connection, pi->vnr);
2187         if (!peer_device)
2188                 return -EIO;
2189         device = peer_device->device;
2190
2191         sector = be64_to_cpu(p->sector);
2192         D_ASSERT(device, p->block_id == ID_SYNCER);
2193
2194         if (get_ldev(device)) {
2195                 /* data is submitted to disk within recv_resync_read.
2196                  * corresponding put_ldev done below on error,
2197                  * or in drbd_peer_request_endio. */
2198                 err = recv_resync_read(peer_device, sector, pi);
2199         } else {
2200                 if (__ratelimit(&drbd_ratelimit_state))
2201                         drbd_err(device, "Can not write resync data to local disk.\n");
2202
2203                 err = drbd_drain_block(peer_device, pi->size);
2204
2205                 drbd_send_ack_dp(peer_device, P_NEG_ACK, p, pi->size);
2206         }
2207
2208         atomic_add(pi->size >> 9, &device->rs_sect_in);
2209
2210         return err;
2211 }
2212
2213 static void restart_conflicting_writes(struct drbd_device *device,
2214                                        sector_t sector, int size)
2215 {
2216         struct drbd_interval *i;
2217         struct drbd_request *req;
2218
2219         drbd_for_each_overlap(i, &device->write_requests, sector, size) {
2220                 if (!i->local)
2221                         continue;
2222                 req = container_of(i, struct drbd_request, i);
2223                 if (req->rq_state & RQ_LOCAL_PENDING ||
2224                     !(req->rq_state & RQ_POSTPONED))
2225                         continue;
2226                 /* as it is RQ_POSTPONED, this will cause it to
2227                  * be queued on the retry workqueue. */
2228                 __req_mod(req, CONFLICT_RESOLVED, NULL);
2229         }
2230 }
2231
2232 /*
2233  * e_end_block() is called in ack_sender context via drbd_finish_peer_reqs().
2234  */
2235 static int e_end_block(struct drbd_work *w, int cancel)
2236 {
2237         struct drbd_peer_request *peer_req =
2238                 container_of(w, struct drbd_peer_request, w);
2239         struct drbd_peer_device *peer_device = peer_req->peer_device;
2240         struct drbd_device *device = peer_device->device;
2241         sector_t sector = peer_req->i.sector;
2242         int err = 0, pcmd;
2243
2244         if (peer_req->flags & EE_SEND_WRITE_ACK) {
2245                 if (likely((peer_req->flags & EE_WAS_ERROR) == 0)) {
2246                         pcmd = (device->state.conn >= C_SYNC_SOURCE &&
2247                                 device->state.conn <= C_PAUSED_SYNC_T &&
2248                                 peer_req->flags & EE_MAY_SET_IN_SYNC) ?
2249                                 P_RS_WRITE_ACK : P_WRITE_ACK;
2250                         err = drbd_send_ack(peer_device, pcmd, peer_req);
2251                         if (pcmd == P_RS_WRITE_ACK)
2252                                 drbd_set_in_sync(device, sector, peer_req->i.size);
2253                 } else {
2254                         err = drbd_send_ack(peer_device, P_NEG_ACK, peer_req);
2255                         /* we expect it to be marked out of sync anyways...
2256                          * maybe assert this?  */
2257                 }
2258                 dec_unacked(device);
2259         }
2260
2261         /* we delete from the conflict detection hash _after_ we sent out the
2262          * P_WRITE_ACK / P_NEG_ACK, to get the sequence number right.  */
2263         if (peer_req->flags & EE_IN_INTERVAL_TREE) {
2264                 spin_lock_irq(&device->resource->req_lock);
2265                 D_ASSERT(device, !drbd_interval_empty(&peer_req->i));
2266                 drbd_remove_epoch_entry_interval(device, peer_req);
2267                 if (peer_req->flags & EE_RESTART_REQUESTS)
2268                         restart_conflicting_writes(device, sector, peer_req->i.size);
2269                 spin_unlock_irq(&device->resource->req_lock);
2270         } else
2271                 D_ASSERT(device, drbd_interval_empty(&peer_req->i));
2272
2273         drbd_may_finish_epoch(peer_device->connection, peer_req->epoch, EV_PUT + (cancel ? EV_CLEANUP : 0));
2274
2275         return err;
2276 }
2277
2278 static int e_send_ack(struct drbd_work *w, enum drbd_packet ack)
2279 {
2280         struct drbd_peer_request *peer_req =
2281                 container_of(w, struct drbd_peer_request, w);
2282         struct drbd_peer_device *peer_device = peer_req->peer_device;
2283         int err;
2284
2285         err = drbd_send_ack(peer_device, ack, peer_req);
2286         dec_unacked(peer_device->device);
2287
2288         return err;
2289 }
2290
2291 static int e_send_superseded(struct drbd_work *w, int unused)
2292 {
2293         return e_send_ack(w, P_SUPERSEDED);
2294 }
2295
2296 static int e_send_retry_write(struct drbd_work *w, int unused)
2297 {
2298         struct drbd_peer_request *peer_req =
2299                 container_of(w, struct drbd_peer_request, w);
2300         struct drbd_connection *connection = peer_req->peer_device->connection;
2301
2302         return e_send_ack(w, connection->agreed_pro_version >= 100 ?
2303                              P_RETRY_WRITE : P_SUPERSEDED);
2304 }
2305
2306 static bool seq_greater(u32 a, u32 b)
2307 {
2308         /*
2309          * We assume 32-bit wrap-around here.
2310          * For 24-bit wrap-around, we would have to shift:
2311          *  a <<= 8; b <<= 8;
2312          */
2313         return (s32)a - (s32)b > 0;
2314 }
2315
2316 static u32 seq_max(u32 a, u32 b)
2317 {
2318         return seq_greater(a, b) ? a : b;
2319 }
2320
2321 static void update_peer_seq(struct drbd_peer_device *peer_device, unsigned int peer_seq)
2322 {
2323         struct drbd_device *device = peer_device->device;
2324         unsigned int newest_peer_seq;
2325
2326         if (test_bit(RESOLVE_CONFLICTS, &peer_device->connection->flags)) {
2327                 spin_lock(&device->peer_seq_lock);
2328                 newest_peer_seq = seq_max(device->peer_seq, peer_seq);
2329                 device->peer_seq = newest_peer_seq;
2330                 spin_unlock(&device->peer_seq_lock);
2331                 /* wake up only if we actually changed device->peer_seq */
2332                 if (peer_seq == newest_peer_seq)
2333                         wake_up(&device->seq_wait);
2334         }
2335 }
2336
2337 static inline int overlaps(sector_t s1, int l1, sector_t s2, int l2)
2338 {
2339         return !((s1 + (l1>>9) <= s2) || (s1 >= s2 + (l2>>9)));
2340 }
2341
2342 /* maybe change sync_ee into interval trees as well? */
2343 static bool overlapping_resync_write(struct drbd_device *device, struct drbd_peer_request *peer_req)
2344 {
2345         struct drbd_peer_request *rs_req;
2346         bool rv = false;
2347
2348         spin_lock_irq(&device->resource->req_lock);
2349         list_for_each_entry(rs_req, &device->sync_ee, w.list) {
2350                 if (overlaps(peer_req->i.sector, peer_req->i.size,
2351                              rs_req->i.sector, rs_req->i.size)) {
2352                         rv = true;
2353                         break;
2354                 }
2355         }
2356         spin_unlock_irq(&device->resource->req_lock);
2357
2358         return rv;
2359 }
2360
2361 /* Called from receive_Data.
2362  * Synchronize packets on sock with packets on msock.
2363  *
2364  * This is here so even when a P_DATA packet traveling via sock overtook an Ack
2365  * packet traveling on msock, they are still processed in the order they have
2366  * been sent.
2367  *
2368  * Note: we don't care for Ack packets overtaking P_DATA packets.
2369  *
2370  * In case packet_seq is larger than device->peer_seq number, there are
2371  * outstanding packets on the msock. We wait for them to arrive.
2372  * In case we are the logically next packet, we update device->peer_seq
2373  * ourselves. Correctly handles 32bit wrap around.
2374  *
2375  * Assume we have a 10 GBit connection, that is about 1<<30 byte per second,
2376  * about 1<<21 sectors per second. So "worst" case, we have 1<<3 == 8 seconds
2377  * for the 24bit wrap (historical atomic_t guarantee on some archs), and we have
2378  * 1<<9 == 512 seconds aka ages for the 32bit wrap around...
2379  *
2380  * returns 0 if we may process the packet,
2381  * -ERESTARTSYS if we were interrupted (by disconnect signal). */
2382 static int wait_for_and_update_peer_seq(struct drbd_peer_device *peer_device, const u32 peer_seq)
2383 {
2384         struct drbd_device *device = peer_device->device;
2385         DEFINE_WAIT(wait);
2386         long timeout;
2387         int ret = 0, tp;
2388
2389         if (!test_bit(RESOLVE_CONFLICTS, &peer_device->connection->flags))
2390                 return 0;
2391
2392         spin_lock(&device->peer_seq_lock);
2393         for (;;) {
2394                 if (!seq_greater(peer_seq - 1, device->peer_seq)) {
2395                         device->peer_seq = seq_max(device->peer_seq, peer_seq);
2396                         break;
2397                 }
2398
2399                 if (signal_pending(current)) {
2400                         ret = -ERESTARTSYS;
2401                         break;
2402                 }
2403
2404                 rcu_read_lock();
2405                 tp = rcu_dereference(peer_device->connection->net_conf)->two_primaries;
2406                 rcu_read_unlock();
2407
2408                 if (!tp)
2409                         break;
2410
2411                 /* Only need to wait if two_primaries is enabled */
2412                 prepare_to_wait(&device->seq_wait, &wait, TASK_INTERRUPTIBLE);
2413                 spin_unlock(&device->peer_seq_lock);
2414                 rcu_read_lock();
2415                 timeout = rcu_dereference(peer_device->connection->net_conf)->ping_timeo*HZ/10;
2416                 rcu_read_unlock();
2417                 timeout = schedule_timeout(timeout);
2418                 spin_lock(&device->peer_seq_lock);
2419                 if (!timeout) {
2420                         ret = -ETIMEDOUT;
2421                         drbd_err(device, "Timed out waiting for missing ack packets; disconnecting\n");
2422                         break;
2423                 }
2424         }
2425         spin_unlock(&device->peer_seq_lock);
2426         finish_wait(&device->seq_wait, &wait);
2427         return ret;
2428 }
2429
2430 /* see also bio_flags_to_wire()
2431  * DRBD_REQ_*, because we need to semantically map the flags to data packet
2432  * flags and back. We may replicate to other kernel versions. */
2433 static unsigned long wire_flags_to_bio_flags(u32 dpf)
2434 {
2435         return  (dpf & DP_RW_SYNC ? REQ_SYNC : 0) |
2436                 (dpf & DP_FUA ? REQ_FUA : 0) |
2437                 (dpf & DP_FLUSH ? REQ_PREFLUSH : 0);
2438 }
2439
2440 static unsigned long wire_flags_to_bio_op(u32 dpf)
2441 {
2442         if (dpf & DP_ZEROES)
2443                 return REQ_OP_WRITE_ZEROES;
2444         if (dpf & DP_DISCARD)
2445                 return REQ_OP_DISCARD;
2446         if (dpf & DP_WSAME)
2447                 return REQ_OP_WRITE_SAME;
2448         else
2449                 return REQ_OP_WRITE;
2450 }
2451
2452 static void fail_postponed_requests(struct drbd_device *device, sector_t sector,
2453                                     unsigned int size)
2454 {
2455         struct drbd_interval *i;
2456
2457     repeat:
2458         drbd_for_each_overlap(i, &device->write_requests, sector, size) {
2459                 struct drbd_request *req;
2460                 struct bio_and_error m;
2461
2462                 if (!i->local)
2463                         continue;
2464                 req = container_of(i, struct drbd_request, i);
2465                 if (!(req->rq_state & RQ_POSTPONED))
2466                         continue;
2467                 req->rq_state &= ~RQ_POSTPONED;
2468                 __req_mod(req, NEG_ACKED, &m);
2469                 spin_unlock_irq(&device->resource->req_lock);
2470                 if (m.bio)
2471                         complete_master_bio(device, &m);
2472                 spin_lock_irq(&device->resource->req_lock);
2473                 goto repeat;
2474         }
2475 }
2476
2477 static int handle_write_conflicts(struct drbd_device *device,
2478                                   struct drbd_peer_request *peer_req)
2479 {
2480         struct drbd_connection *connection = peer_req->peer_device->connection;
2481         bool resolve_conflicts = test_bit(RESOLVE_CONFLICTS, &connection->flags);
2482         sector_t sector = peer_req->i.sector;
2483         const unsigned int size = peer_req->i.size;
2484         struct drbd_interval *i;
2485         bool equal;
2486         int err;
2487
2488         /*
2489          * Inserting the peer request into the write_requests tree will prevent
2490          * new conflicting local requests from being added.
2491          */
2492         drbd_insert_interval(&device->write_requests, &peer_req->i);
2493
2494     repeat:
2495         drbd_for_each_overlap(i, &device->write_requests, sector, size) {
2496                 if (i == &peer_req->i)
2497                         continue;
2498                 if (i->completed)
2499                         continue;
2500
2501                 if (!i->local) {
2502                         /*
2503                          * Our peer has sent a conflicting remote request; this
2504                          * should not happen in a two-node setup.  Wait for the
2505                          * earlier peer request to complete.
2506                          */
2507                         err = drbd_wait_misc(device, i);
2508                         if (err)
2509                                 goto out;
2510                         goto repeat;
2511                 }
2512
2513                 equal = i->sector == sector && i->size == size;
2514                 if (resolve_conflicts) {
2515                         /*
2516                          * If the peer request is fully contained within the
2517                          * overlapping request, it can be considered overwritten
2518                          * and thus superseded; otherwise, it will be retried
2519                          * once all overlapping requests have completed.
2520                          */
2521                         bool superseded = i->sector <= sector && i->sector +
2522                                        (i->size >> 9) >= sector + (size >> 9);
2523
2524                         if (!equal)
2525                                 drbd_alert(device, "Concurrent writes detected: "
2526                                                "local=%llus +%u, remote=%llus +%u, "
2527                                                "assuming %s came first\n",
2528                                           (unsigned long long)i->sector, i->size,
2529                                           (unsigned long long)sector, size,
2530                                           superseded ? "local" : "remote");
2531
2532                         peer_req->w.cb = superseded ? e_send_superseded :
2533                                                    e_send_retry_write;
2534                         list_add_tail(&peer_req->w.list, &device->done_ee);
2535                         queue_work(connection->ack_sender, &peer_req->peer_device->send_acks_work);
2536
2537                         err = -ENOENT;
2538                         goto out;
2539                 } else {
2540                         struct drbd_request *req =
2541                                 container_of(i, struct drbd_request, i);
2542
2543                         if (!equal)
2544                                 drbd_alert(device, "Concurrent writes detected: "
2545                                                "local=%llus +%u, remote=%llus +%u\n",
2546                                           (unsigned long long)i->sector, i->size,
2547                                           (unsigned long long)sector, size);
2548
2549                         if (req->rq_state & RQ_LOCAL_PENDING ||
2550                             !(req->rq_state & RQ_POSTPONED)) {
2551                                 /*
2552                                  * Wait for the node with the discard flag to
2553                                  * decide if this request has been superseded
2554                                  * or needs to be retried.
2555                                  * Requests that have been superseded will
2556                                  * disappear from the write_requests tree.
2557                                  *
2558                                  * In addition, wait for the conflicting
2559                                  * request to finish locally before submitting
2560                                  * the conflicting peer request.
2561                                  */
2562                                 err = drbd_wait_misc(device, &req->i);
2563                                 if (err) {
2564                                         _conn_request_state(connection, NS(conn, C_TIMEOUT), CS_HARD);
2565                                         fail_postponed_requests(device, sector, size);
2566                                         goto out;
2567                                 }
2568                                 goto repeat;
2569                         }
2570                         /*
2571                          * Remember to restart the conflicting requests after
2572                          * the new peer request has completed.
2573                          */
2574                         peer_req->flags |= EE_RESTART_REQUESTS;
2575                 }
2576         }
2577         err = 0;
2578
2579     out:
2580         if (err)
2581                 drbd_remove_epoch_entry_interval(device, peer_req);
2582         return err;
2583 }
2584
2585 /* mirrored write */
2586 static int receive_Data(struct drbd_connection *connection, struct packet_info *pi)
2587 {
2588         struct drbd_peer_device *peer_device;
2589         struct drbd_device *device;
2590         struct net_conf *nc;
2591         sector_t sector;
2592         struct drbd_peer_request *peer_req;
2593         struct p_data *p = pi->data;
2594         u32 peer_seq = be32_to_cpu(p->seq_num);
2595         int op, op_flags;
2596         u32 dp_flags;
2597         int err, tp;
2598
2599         peer_device = conn_peer_device(connection, pi->vnr);
2600         if (!peer_device)
2601                 return -EIO;
2602         device = peer_device->device;
2603
2604         if (!get_ldev(device)) {
2605                 int err2;
2606
2607                 err = wait_for_and_update_peer_seq(peer_device, peer_seq);
2608                 drbd_send_ack_dp(peer_device, P_NEG_ACK, p, pi->size);
2609                 atomic_inc(&connection->current_epoch->epoch_size);
2610                 err2 = drbd_drain_block(peer_device, pi->size);
2611                 if (!err)
2612                         err = err2;
2613                 return err;
2614         }
2615
2616         /*
2617          * Corresponding put_ldev done either below (on various errors), or in
2618          * drbd_peer_request_endio, if we successfully submit the data at the
2619          * end of this function.
2620          */
2621
2622         sector = be64_to_cpu(p->sector);
2623         peer_req = read_in_block(peer_device, p->block_id, sector, pi);
2624         if (!peer_req) {
2625                 put_ldev(device);
2626                 return -EIO;
2627         }
2628
2629         peer_req->w.cb = e_end_block;
2630         peer_req->submit_jif = jiffies;
2631         peer_req->flags |= EE_APPLICATION;
2632
2633         dp_flags = be32_to_cpu(p->dp_flags);
2634         op = wire_flags_to_bio_op(dp_flags);
2635         op_flags = wire_flags_to_bio_flags(dp_flags);
2636         if (pi->cmd == P_TRIM) {
2637                 D_ASSERT(peer_device, peer_req->i.size > 0);
2638                 D_ASSERT(peer_device, op == REQ_OP_DISCARD);
2639                 D_ASSERT(peer_device, peer_req->pages == NULL);
2640                 /* need to play safe: an older DRBD sender
2641                  * may mean zero-out while sending P_TRIM. */
2642                 if (0 == (connection->agreed_features & DRBD_FF_WZEROES))
2643                         peer_req->flags |= EE_ZEROOUT;
2644         } else if (pi->cmd == P_ZEROES) {
2645                 D_ASSERT(peer_device, peer_req->i.size > 0);
2646                 D_ASSERT(peer_device, op == REQ_OP_WRITE_ZEROES);
2647                 D_ASSERT(peer_device, peer_req->pages == NULL);
2648                 /* Do (not) pass down BLKDEV_ZERO_NOUNMAP? */
2649                 if (dp_flags & DP_DISCARD)
2650                         peer_req->flags |= EE_TRIM;
2651         } else if (peer_req->pages == NULL) {
2652                 D_ASSERT(device, peer_req->i.size == 0);
2653                 D_ASSERT(device, dp_flags & DP_FLUSH);
2654         }
2655
2656         if (dp_flags & DP_MAY_SET_IN_SYNC)
2657                 peer_req->flags |= EE_MAY_SET_IN_SYNC;
2658
2659         spin_lock(&connection->epoch_lock);
2660         peer_req->epoch = connection->current_epoch;
2661         atomic_inc(&peer_req->epoch->epoch_size);
2662         atomic_inc(&peer_req->epoch->active);
2663         spin_unlock(&connection->epoch_lock);
2664
2665         rcu_read_lock();
2666         nc = rcu_dereference(peer_device->connection->net_conf);
2667         tp = nc->two_primaries;
2668         if (peer_device->connection->agreed_pro_version < 100) {
2669                 switch (nc->wire_protocol) {
2670                 case DRBD_PROT_C:
2671                         dp_flags |= DP_SEND_WRITE_ACK;
2672                         break;
2673                 case DRBD_PROT_B:
2674                         dp_flags |= DP_SEND_RECEIVE_ACK;
2675                         break;
2676                 }
2677         }
2678         rcu_read_unlock();
2679
2680         if (dp_flags & DP_SEND_WRITE_ACK) {
2681                 peer_req->flags |= EE_SEND_WRITE_ACK;
2682                 inc_unacked(device);
2683                 /* corresponding dec_unacked() in e_end_block()
2684                  * respective _drbd_clear_done_ee */
2685         }
2686
2687         if (dp_flags & DP_SEND_RECEIVE_ACK) {
2688                 /* I really don't like it that the receiver thread
2689                  * sends on the msock, but anyways */
2690                 drbd_send_ack(peer_device, P_RECV_ACK, peer_req);
2691         }
2692
2693         if (tp) {
2694                 /* two primaries implies protocol C */
2695                 D_ASSERT(device, dp_flags & DP_SEND_WRITE_ACK);
2696                 peer_req->flags |= EE_IN_INTERVAL_TREE;
2697                 err = wait_for_and_update_peer_seq(peer_device, peer_seq);
2698                 if (err)
2699                         goto out_interrupted;
2700                 spin_lock_irq(&device->resource->req_lock);
2701                 err = handle_write_conflicts(device, peer_req);
2702                 if (err) {
2703                         spin_unlock_irq(&device->resource->req_lock);
2704                         if (err == -ENOENT) {
2705                                 put_ldev(device);
2706                                 return 0;
2707                         }
2708                         goto out_interrupted;
2709                 }
2710         } else {
2711                 update_peer_seq(peer_device, peer_seq);
2712                 spin_lock_irq(&device->resource->req_lock);
2713         }
2714         /* TRIM and WRITE_SAME are processed synchronously,
2715          * we wait for all pending requests, respectively wait for
2716          * active_ee to become empty in drbd_submit_peer_request();
2717          * better not add ourselves here. */
2718         if ((peer_req->flags & (EE_TRIM|EE_WRITE_SAME|EE_ZEROOUT)) == 0)
2719                 list_add_tail(&peer_req->w.list, &device->active_ee);
2720         spin_unlock_irq(&device->resource->req_lock);
2721
2722         if (device->state.conn == C_SYNC_TARGET)
2723                 wait_event(device->ee_wait, !overlapping_resync_write(device, peer_req));
2724
2725         if (device->state.pdsk < D_INCONSISTENT) {
2726                 /* In case we have the only disk of the cluster, */
2727                 drbd_set_out_of_sync(device, peer_req->i.sector, peer_req->i.size);
2728                 peer_req->flags &= ~EE_MAY_SET_IN_SYNC;
2729                 drbd_al_begin_io(device, &peer_req->i);
2730                 peer_req->flags |= EE_CALL_AL_COMPLETE_IO;
2731         }
2732
2733         err = drbd_submit_peer_request(device, peer_req, op, op_flags,
2734                                        DRBD_FAULT_DT_WR);
2735         if (!err)
2736                 return 0;
2737
2738         /* don't care for the reason here */
2739         drbd_err(device, "submit failed, triggering re-connect\n");
2740         spin_lock_irq(&device->resource->req_lock);
2741         list_del(&peer_req->w.list);
2742         drbd_remove_epoch_entry_interval(device, peer_req);
2743         spin_unlock_irq(&device->resource->req_lock);
2744         if (peer_req->flags & EE_CALL_AL_COMPLETE_IO) {
2745                 peer_req->flags &= ~EE_CALL_AL_COMPLETE_IO;
2746                 drbd_al_complete_io(device, &peer_req->i);
2747         }
2748
2749 out_interrupted:
2750         drbd_may_finish_epoch(connection, peer_req->epoch, EV_PUT | EV_CLEANUP);
2751         put_ldev(device);
2752         drbd_free_peer_req(device, peer_req);
2753         return err;
2754 }
2755
2756 /* We may throttle resync, if the lower device seems to be busy,
2757  * and current sync rate is above c_min_rate.
2758  *
2759  * To decide whether or not the lower device is busy, we use a scheme similar
2760  * to MD RAID is_mddev_idle(): if the partition stats reveal "significant"
2761  * (more than 64 sectors) of activity we cannot account for with our own resync
2762  * activity, it obviously is "busy".
2763  *
2764  * The current sync rate used here uses only the most recent two step marks,
2765  * to have a short time average so we can react faster.
2766  */
2767 bool drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector,
2768                 bool throttle_if_app_is_waiting)
2769 {
2770         struct lc_element *tmp;
2771         bool throttle = drbd_rs_c_min_rate_throttle(device);
2772
2773         if (!throttle || throttle_if_app_is_waiting)
2774                 return throttle;
2775
2776         spin_lock_irq(&device->al_lock);
2777         tmp = lc_find(device->resync, BM_SECT_TO_EXT(sector));
2778         if (tmp) {
2779                 struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
2780                 if (test_bit(BME_PRIORITY, &bm_ext->flags))
2781                         throttle = false;
2782                 /* Do not slow down if app IO is already waiting for this extent,
2783                  * and our progress is necessary for application IO to complete. */
2784         }
2785         spin_unlock_irq(&device->al_lock);
2786
2787         return throttle;
2788 }
2789
2790 bool drbd_rs_c_min_rate_throttle(struct drbd_device *device)
2791 {
2792         struct gendisk *disk = device->ldev->backing_bdev->bd_disk;
2793         unsigned long db, dt, dbdt;
2794         unsigned int c_min_rate;
2795         int curr_events;
2796
2797         rcu_read_lock();
2798         c_min_rate = rcu_dereference(device->ldev->disk_conf)->c_min_rate;
2799         rcu_read_unlock();
2800
2801         /* feature disabled? */
2802         if (c_min_rate == 0)
2803                 return false;
2804
2805         curr_events = (int)part_stat_read_accum(disk->part0, sectors) -
2806                         atomic_read(&device->rs_sect_ev);
2807
2808         if (atomic_read(&device->ap_actlog_cnt)
2809             || curr_events - device->rs_last_events > 64) {
2810                 unsigned long rs_left;
2811                 int i;
2812
2813                 device->rs_last_events = curr_events;
2814
2815                 /* sync speed average over the last 2*DRBD_SYNC_MARK_STEP,
2816                  * approx. */
2817                 i = (device->rs_last_mark + DRBD_SYNC_MARKS-1) % DRBD_SYNC_MARKS;
2818
2819                 if (device->state.conn == C_VERIFY_S || device->state.conn == C_VERIFY_T)
2820                         rs_left = device->ov_left;
2821                 else
2822                         rs_left = drbd_bm_total_weight(device) - device->rs_failed;
2823
2824                 dt = ((long)jiffies - (long)device->rs_mark_time[i]) / HZ;
2825                 if (!dt)
2826                         dt++;
2827                 db = device->rs_mark_left[i] - rs_left;
2828                 dbdt = Bit2KB(db/dt);
2829
2830                 if (dbdt > c_min_rate)
2831                         return true;
2832         }
2833         return false;
2834 }
2835
2836 static int receive_DataRequest(struct drbd_connection *connection, struct packet_info *pi)
2837 {
2838         struct drbd_peer_device *peer_device;
2839         struct drbd_device *device;
2840         sector_t sector;
2841         sector_t capacity;
2842         struct drbd_peer_request *peer_req;
2843         struct digest_info *di = NULL;
2844         int size, verb;
2845         unsigned int fault_type;
2846         struct p_block_req *p = pi->data;
2847
2848         peer_device = conn_peer_device(connection, pi->vnr);
2849         if (!peer_device)
2850                 return -EIO;
2851         device = peer_device->device;
2852         capacity = get_capacity(device->vdisk);
2853
2854         sector = be64_to_cpu(p->sector);
2855         size   = be32_to_cpu(p->blksize);
2856
2857         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
2858                 drbd_err(device, "%s:%d: sector: %llus, size: %u\n", __FILE__, __LINE__,
2859                                 (unsigned long long)sector, size);
2860                 return -EINVAL;
2861         }
2862         if (sector + (size>>9) > capacity) {
2863                 drbd_err(device, "%s:%d: sector: %llus, size: %u\n", __FILE__, __LINE__,
2864                                 (unsigned long long)sector, size);
2865                 return -EINVAL;
2866         }
2867
2868         if (!get_ldev_if_state(device, D_UP_TO_DATE)) {
2869                 verb = 1;
2870                 switch (pi->cmd) {
2871                 case P_DATA_REQUEST:
2872                         drbd_send_ack_rp(peer_device, P_NEG_DREPLY, p);
2873                         break;
2874                 case P_RS_THIN_REQ:
2875                 case P_RS_DATA_REQUEST:
2876                 case P_CSUM_RS_REQUEST:
2877                 case P_OV_REQUEST:
2878                         drbd_send_ack_rp(peer_device, P_NEG_RS_DREPLY , p);
2879                         break;
2880                 case P_OV_REPLY:
2881                         verb = 0;
2882                         dec_rs_pending(device);
2883                         drbd_send_ack_ex(peer_device, P_OV_RESULT, sector, size, ID_IN_SYNC);
2884                         break;
2885                 default:
2886                         BUG();
2887                 }
2888                 if (verb && __ratelimit(&drbd_ratelimit_state))
2889                         drbd_err(device, "Can not satisfy peer's read request, "
2890                             "no local data.\n");
2891
2892                 /* drain possibly payload */
2893                 return drbd_drain_block(peer_device, pi->size);
2894         }
2895
2896         /* GFP_NOIO, because we must not cause arbitrary write-out: in a DRBD
2897          * "criss-cross" setup, that might cause write-out on some other DRBD,
2898          * which in turn might block on the other node at this very place.  */
2899         peer_req = drbd_alloc_peer_req(peer_device, p->block_id, sector, size,
2900                         size, GFP_NOIO);
2901         if (!peer_req) {
2902                 put_ldev(device);
2903                 return -ENOMEM;
2904         }
2905
2906         switch (pi->cmd) {
2907         case P_DATA_REQUEST:
2908                 peer_req->w.cb = w_e_end_data_req;
2909                 fault_type = DRBD_FAULT_DT_RD;
2910                 /* application IO, don't drbd_rs_begin_io */
2911                 peer_req->flags |= EE_APPLICATION;
2912                 goto submit;
2913
2914         case P_RS_THIN_REQ:
2915                 /* If at some point in the future we have a smart way to
2916                    find out if this data block is completely deallocated,
2917                    then we would do something smarter here than reading
2918                    the block... */
2919                 peer_req->flags |= EE_RS_THIN_REQ;
2920                 fallthrough;
2921         case P_RS_DATA_REQUEST:
2922                 peer_req->w.cb = w_e_end_rsdata_req;
2923                 fault_type = DRBD_FAULT_RS_RD;
2924                 /* used in the sector offset progress display */
2925                 device->bm_resync_fo = BM_SECT_TO_BIT(sector);
2926                 break;
2927
2928         case P_OV_REPLY:
2929         case P_CSUM_RS_REQUEST:
2930                 fault_type = DRBD_FAULT_RS_RD;
2931                 di = kmalloc(sizeof(*di) + pi->size, GFP_NOIO);
2932                 if (!di)
2933                         goto out_free_e;
2934
2935                 di->digest_size = pi->size;
2936                 di->digest = (((char *)di)+sizeof(struct digest_info));
2937
2938                 peer_req->digest = di;
2939                 peer_req->flags |= EE_HAS_DIGEST;
2940
2941                 if (drbd_recv_all(peer_device->connection, di->digest, pi->size))
2942                         goto out_free_e;
2943
2944                 if (pi->cmd == P_CSUM_RS_REQUEST) {
2945                         D_ASSERT(device, peer_device->connection->agreed_pro_version >= 89);
2946                         peer_req->w.cb = w_e_end_csum_rs_req;
2947                         /* used in the sector offset progress display */
2948                         device->bm_resync_fo = BM_SECT_TO_BIT(sector);
2949                         /* remember to report stats in drbd_resync_finished */
2950                         device->use_csums = true;
2951                 } else if (pi->cmd == P_OV_REPLY) {
2952                         /* track progress, we may need to throttle */
2953                         atomic_add(size >> 9, &device->rs_sect_in);
2954                         peer_req->w.cb = w_e_end_ov_reply;
2955                         dec_rs_pending(device);
2956                         /* drbd_rs_begin_io done when we sent this request,
2957                          * but accounting still needs to be done. */
2958                         goto submit_for_resync;
2959                 }
2960                 break;
2961
2962         case P_OV_REQUEST:
2963                 if (device->ov_start_sector == ~(sector_t)0 &&
2964                     peer_device->connection->agreed_pro_version >= 90) {
2965                         unsigned long now = jiffies;
2966                         int i;
2967                         device->ov_start_sector = sector;
2968                         device->ov_position = sector;
2969                         device->ov_left = drbd_bm_bits(device) - BM_SECT_TO_BIT(sector);
2970                         device->rs_total = device->ov_left;
2971                         for (i = 0; i < DRBD_SYNC_MARKS; i++) {
2972                                 device->rs_mark_left[i] = device->ov_left;
2973                                 device->rs_mark_time[i] = now;
2974                         }
2975                         drbd_info(device, "Online Verify start sector: %llu\n",
2976                                         (unsigned long long)sector);
2977                 }
2978                 peer_req->w.cb = w_e_end_ov_req;
2979                 fault_type = DRBD_FAULT_RS_RD;
2980                 break;
2981
2982         default:
2983                 BUG();
2984         }
2985
2986         /* Throttle, drbd_rs_begin_io and submit should become asynchronous
2987          * wrt the receiver, but it is not as straightforward as it may seem.
2988          * Various places in the resync start and stop logic assume resync
2989          * requests are processed in order, requeuing this on the worker thread
2990          * introduces a bunch of new code for synchronization between threads.
2991          *
2992          * Unlimited throttling before drbd_rs_begin_io may stall the resync
2993          * "forever", throttling after drbd_rs_begin_io will lock that extent
2994          * for application writes for the same time.  For now, just throttle
2995          * here, where the rest of the code expects the receiver to sleep for
2996          * a while, anyways.
2997          */
2998
2999         /* Throttle before drbd_rs_begin_io, as that locks out application IO;
3000          * this defers syncer requests for some time, before letting at least
3001          * on request through.  The resync controller on the receiving side
3002          * will adapt to the incoming rate accordingly.
3003          *
3004          * We cannot throttle here if remote is Primary/SyncTarget:
3005          * we would also throttle its application reads.
3006          * In that case, throttling is done on the SyncTarget only.
3007          */
3008
3009         /* Even though this may be a resync request, we do add to "read_ee";
3010          * "sync_ee" is only used for resync WRITEs.
3011          * Add to list early, so debugfs can find this request
3012          * even if we have to sleep below. */
3013         spin_lock_irq(&device->resource->req_lock);
3014         list_add_tail(&peer_req->w.list, &device->read_ee);
3015         spin_unlock_irq(&device->resource->req_lock);
3016
3017         update_receiver_timing_details(connection, drbd_rs_should_slow_down);
3018         if (device->state.peer != R_PRIMARY
3019         && drbd_rs_should_slow_down(device, sector, false))
3020                 schedule_timeout_uninterruptible(HZ/10);
3021         update_receiver_timing_details(connection, drbd_rs_begin_io);
3022         if (drbd_rs_begin_io(device, sector))
3023                 goto out_free_e;
3024
3025 submit_for_resync:
3026         atomic_add(size >> 9, &device->rs_sect_ev);
3027
3028 submit:
3029         update_receiver_timing_details(connection, drbd_submit_peer_request);
3030         inc_unacked(device);
3031         if (drbd_submit_peer_request(device, peer_req, REQ_OP_READ, 0,
3032                                      fault_type) == 0)
3033                 return 0;
3034
3035         /* don't care for the reason here */
3036         drbd_err(device, "submit failed, triggering re-connect\n");
3037
3038 out_free_e:
3039         spin_lock_irq(&device->resource->req_lock);
3040         list_del(&peer_req->w.list);
3041         spin_unlock_irq(&device->resource->req_lock);
3042         /* no drbd_rs_complete_io(), we are dropping the connection anyways */
3043
3044         put_ldev(device);
3045         drbd_free_peer_req(device, peer_req);
3046         return -EIO;
3047 }
3048
3049 /*
3050  * drbd_asb_recover_0p  -  Recover after split-brain with no remaining primaries
3051  */
3052 static int drbd_asb_recover_0p(struct drbd_peer_device *peer_device) __must_hold(local)
3053 {
3054         struct drbd_device *device = peer_device->device;
3055         int self, peer, rv = -100;
3056         unsigned long ch_self, ch_peer;
3057         enum drbd_after_sb_p after_sb_0p;
3058
3059         self = device->ldev->md.uuid[UI_BITMAP] & 1;
3060         peer = device->p_uuid[UI_BITMAP] & 1;
3061
3062         ch_peer = device->p_uuid[UI_SIZE];
3063         ch_self = device->comm_bm_set;
3064
3065         rcu_read_lock();
3066         after_sb_0p = rcu_dereference(peer_device->connection->net_conf)->after_sb_0p;
3067         rcu_read_unlock();
3068         switch (after_sb_0p) {
3069         case ASB_CONSENSUS:
3070         case ASB_DISCARD_SECONDARY:
3071         case ASB_CALL_HELPER:
3072         case ASB_VIOLENTLY:
3073                 drbd_err(device, "Configuration error.\n");
3074                 break;
3075         case ASB_DISCONNECT:
3076                 break;
3077         case ASB_DISCARD_YOUNGER_PRI:
3078                 if (self == 0 && peer == 1) {
3079                         rv = -1;
3080                         break;
3081                 }
3082                 if (self == 1 && peer == 0) {
3083                         rv =  1;
3084                         break;
3085                 }
3086                 fallthrough;    /* to one of the other strategies */
3087         case ASB_DISCARD_OLDER_PRI:
3088                 if (self == 0 && peer == 1) {
3089                         rv = 1;
3090                         break;
3091                 }
3092                 if (self == 1 && peer == 0) {
3093                         rv = -1;
3094                         break;
3095                 }
3096                 /* Else fall through to one of the other strategies... */
3097                 drbd_warn(device, "Discard younger/older primary did not find a decision\n"
3098                      "Using discard-least-changes instead\n");
3099                 fallthrough;
3100         case ASB_DISCARD_ZERO_CHG:
3101                 if (ch_peer == 0 && ch_self == 0) {
3102                         rv = test_bit(RESOLVE_CONFLICTS, &peer_device->connection->flags)
3103                                 ? -1 : 1;
3104                         break;
3105                 } else {
3106                         if (ch_peer == 0) { rv =  1; break; }
3107                         if (ch_self == 0) { rv = -1; break; }
3108                 }
3109                 if (after_sb_0p == ASB_DISCARD_ZERO_CHG)
3110                         break;
3111                 fallthrough;
3112         case ASB_DISCARD_LEAST_CHG:
3113                 if      (ch_self < ch_peer)
3114                         rv = -1;
3115                 else if (ch_self > ch_peer)
3116                         rv =  1;
3117                 else /* ( ch_self == ch_peer ) */
3118                      /* Well, then use something else. */
3119                         rv = test_bit(RESOLVE_CONFLICTS, &peer_device->connection->flags)
3120                                 ? -1 : 1;
3121                 break;
3122         case ASB_DISCARD_LOCAL:
3123                 rv = -1;
3124                 break;
3125         case ASB_DISCARD_REMOTE:
3126                 rv =  1;
3127         }
3128
3129         return rv;
3130 }
3131
3132 /*
3133  * drbd_asb_recover_1p  -  Recover after split-brain with one remaining primary
3134  */
3135 static int drbd_asb_recover_1p(struct drbd_peer_device *peer_device) __must_hold(local)
3136 {
3137         struct drbd_device *device = peer_device->device;
3138         int hg, rv = -100;
3139         enum drbd_after_sb_p after_sb_1p;
3140
3141         rcu_read_lock();
3142         after_sb_1p = rcu_dereference(peer_device->connection->net_conf)->after_sb_1p;
3143         rcu_read_unlock();
3144         switch (after_sb_1p) {
3145         case ASB_DISCARD_YOUNGER_PRI:
3146         case ASB_DISCARD_OLDER_PRI:
3147         case ASB_DISCARD_LEAST_CHG:
3148         case ASB_DISCARD_LOCAL:
3149         case ASB_DISCARD_REMOTE:
3150         case ASB_DISCARD_ZERO_CHG:
3151                 drbd_err(device, "Configuration error.\n");
3152                 break;
3153         case ASB_DISCONNECT:
3154                 break;
3155         case ASB_CONSENSUS:
3156                 hg = drbd_asb_recover_0p(peer_device);
3157                 if (hg == -1 && device->state.role == R_SECONDARY)
3158                         rv = hg;
3159                 if (hg == 1  && device->state.role == R_PRIMARY)
3160                         rv = hg;
3161                 break;
3162         case ASB_VIOLENTLY:
3163                 rv = drbd_asb_recover_0p(peer_device);
3164                 break;
3165         case ASB_DISCARD_SECONDARY:
3166                 return device->state.role == R_PRIMARY ? 1 : -1;
3167         case ASB_CALL_HELPER:
3168                 hg = drbd_asb_recover_0p(peer_device);
3169                 if (hg == -1 && device->state.role == R_PRIMARY) {
3170                         enum drbd_state_rv rv2;
3171
3172                          /* drbd_change_state() does not sleep while in SS_IN_TRANSIENT_STATE,
3173                           * we might be here in C_WF_REPORT_PARAMS which is transient.
3174                           * we do not need to wait for the after state change work either. */
3175                         rv2 = drbd_change_state(device, CS_VERBOSE, NS(role, R_SECONDARY));
3176                         if (rv2 != SS_SUCCESS) {
3177                                 drbd_khelper(device, "pri-lost-after-sb");
3178                         } else {
3179                                 drbd_warn(device, "Successfully gave up primary role.\n");
3180                                 rv = hg;
3181                         }
3182                 } else
3183                         rv = hg;
3184         }
3185
3186         return rv;
3187 }
3188
3189 /*
3190  * drbd_asb_recover_2p  -  Recover after split-brain with two remaining primaries
3191  */
3192 static int drbd_asb_recover_2p(struct drbd_peer_device *peer_device) __must_hold(local)
3193 {
3194         struct drbd_device *device = peer_device->device;
3195         int hg, rv = -100;
3196         enum drbd_after_sb_p after_sb_2p;
3197
3198         rcu_read_lock();
3199         after_sb_2p = rcu_dereference(peer_device->connection->net_conf)->after_sb_2p;
3200         rcu_read_unlock();
3201         switch (after_sb_2p) {
3202         case ASB_DISCARD_YOUNGER_PRI:
3203         case ASB_DISCARD_OLDER_PRI:
3204         case ASB_DISCARD_LEAST_CHG:
3205         case ASB_DISCARD_LOCAL:
3206         case ASB_DISCARD_REMOTE:
3207         case ASB_CONSENSUS:
3208         case ASB_DISCARD_SECONDARY:
3209         case ASB_DISCARD_ZERO_CHG:
3210                 drbd_err(device, "Configuration error.\n");
3211                 break;
3212         case ASB_VIOLENTLY:
3213                 rv = drbd_asb_recover_0p(peer_device);
3214                 break;
3215         case ASB_DISCONNECT:
3216                 break;
3217         case ASB_CALL_HELPER:
3218                 hg = drbd_asb_recover_0p(peer_device);
3219                 if (hg == -1) {
3220                         enum drbd_state_rv rv2;
3221
3222                          /* drbd_change_state() does not sleep while in SS_IN_TRANSIENT_STATE,
3223                           * we might be here in C_WF_REPORT_PARAMS which is transient.
3224                           * we do not need to wait for the after state change work either. */
3225                         rv2 = drbd_change_state(device, CS_VERBOSE, NS(role, R_SECONDARY));
3226                         if (rv2 != SS_SUCCESS) {
3227                                 drbd_khelper(device, "pri-lost-after-sb");
3228                         } else {
3229                                 drbd_warn(device, "Successfully gave up primary role.\n");
3230                                 rv = hg;
3231                         }
3232                 } else
3233                         rv = hg;
3234         }
3235
3236         return rv;
3237 }
3238
3239 static void drbd_uuid_dump(struct drbd_device *device, char *text, u64 *uuid,
3240                            u64 bits, u64 flags)
3241 {
3242         if (!uuid) {
3243                 drbd_info(device, "%s uuid info vanished while I was looking!\n", text);
3244                 return;
3245         }
3246         drbd_info(device, "%s %016llX:%016llX:%016llX:%016llX bits:%llu flags:%llX\n",
3247              text,
3248              (unsigned long long)uuid[UI_CURRENT],
3249              (unsigned long long)uuid[UI_BITMAP],
3250              (unsigned long long)uuid[UI_HISTORY_START],
3251              (unsigned long long)uuid[UI_HISTORY_END],
3252              (unsigned long long)bits,
3253              (unsigned long long)flags);
3254 }
3255
3256 /*
3257   100   after split brain try auto recover
3258     2   C_SYNC_SOURCE set BitMap
3259     1   C_SYNC_SOURCE use BitMap
3260     0   no Sync
3261    -1   C_SYNC_TARGET use BitMap
3262    -2   C_SYNC_TARGET set BitMap
3263  -100   after split brain, disconnect
3264 -1000   unrelated data
3265 -1091   requires proto 91
3266 -1096   requires proto 96
3267  */
3268
3269 static int drbd_uuid_compare(struct drbd_device *const device, enum drbd_role const peer_role, int *rule_nr) __must_hold(local)
3270 {
3271         struct drbd_peer_device *const peer_device = first_peer_device(device);
3272         struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL;
3273         u64 self, peer;
3274         int i, j;
3275
3276         self = device->ldev->md.uuid[UI_CURRENT] & ~((u64)1);
3277         peer = device->p_uuid[UI_CURRENT] & ~((u64)1);
3278
3279         *rule_nr = 10;
3280         if (self == UUID_JUST_CREATED && peer == UUID_JUST_CREATED)
3281                 return 0;
3282
3283         *rule_nr = 20;
3284         if ((self == UUID_JUST_CREATED || self == (u64)0) &&
3285              peer != UUID_JUST_CREATED)
3286                 return -2;
3287
3288         *rule_nr = 30;
3289         if (self != UUID_JUST_CREATED &&
3290             (peer == UUID_JUST_CREATED || peer == (u64)0))
3291                 return 2;
3292
3293         if (self == peer) {
3294                 int rct, dc; /* roles at crash time */
3295
3296                 if (device->p_uuid[UI_BITMAP] == (u64)0 && device->ldev->md.uuid[UI_BITMAP] != (u64)0) {
3297
3298                         if (connection->agreed_pro_version < 91)
3299                                 return -1091;
3300
3301                         if ((device->ldev->md.uuid[UI_BITMAP] & ~((u64)1)) == (device->p_uuid[UI_HISTORY_START] & ~((u64)1)) &&
3302                             (device->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1)) == (device->p_uuid[UI_HISTORY_START + 1] & ~((u64)1))) {
3303                                 drbd_info(device, "was SyncSource, missed the resync finished event, corrected myself:\n");
3304                                 drbd_uuid_move_history(device);
3305                                 device->ldev->md.uuid[UI_HISTORY_START] = device->ldev->md.uuid[UI_BITMAP];
3306                                 device->ldev->md.uuid[UI_BITMAP] = 0;
3307
3308                                 drbd_uuid_dump(device, "self", device->ldev->md.uuid,
3309                                                device->state.disk >= D_NEGOTIATING ? drbd_bm_total_weight(device) : 0, 0);
3310                                 *rule_nr = 34;
3311                         } else {
3312                                 drbd_info(device, "was SyncSource (peer failed to write sync_uuid)\n");
3313                                 *rule_nr = 36;
3314                         }
3315
3316                         return 1;
3317                 }
3318
3319                 if (device->ldev->md.uuid[UI_BITMAP] == (u64)0 && device->p_uuid[UI_BITMAP] != (u64)0) {
3320
3321                         if (connection->agreed_pro_version < 91)
3322                                 return -1091;
3323
3324                         if ((device->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1)) == (device->p_uuid[UI_BITMAP] & ~((u64)1)) &&
3325                             (device->ldev->md.uuid[UI_HISTORY_START + 1] & ~((u64)1)) == (device->p_uuid[UI_HISTORY_START] & ~((u64)1))) {
3326                                 drbd_info(device, "was SyncTarget, peer missed the resync finished event, corrected peer:\n");
3327
3328                                 device->p_uuid[UI_HISTORY_START + 1] = device->p_uuid[UI_HISTORY_START];
3329                                 device->p_uuid[UI_HISTORY_START] = device->p_uuid[UI_BITMAP];
3330                                 device->p_uuid[UI_BITMAP] = 0UL;
3331
3332                                 drbd_uuid_dump(device, "peer", device->p_uuid, device->p_uuid[UI_SIZE], device->p_uuid[UI_FLAGS]);
3333                                 *rule_nr = 35;
3334                         } else {
3335                                 drbd_info(device, "was SyncTarget (failed to write sync_uuid)\n");
3336                                 *rule_nr = 37;
3337                         }
3338
3339                         return -1;
3340                 }
3341
3342                 /* Common power [off|failure] */
3343                 rct = (test_bit(CRASHED_PRIMARY, &device->flags) ? 1 : 0) +
3344                         (device->p_uuid[UI_FLAGS] & 2);
3345                 /* lowest bit is set when we were primary,
3346                  * next bit (weight 2) is set when peer was primary */
3347                 *rule_nr = 40;
3348
3349                 /* Neither has the "crashed primary" flag set,
3350                  * only a replication link hickup. */
3351                 if (rct == 0)
3352                         return 0;
3353
3354                 /* Current UUID equal and no bitmap uuid; does not necessarily
3355                  * mean this was a "simultaneous hard crash", maybe IO was
3356                  * frozen, so no UUID-bump happened.
3357                  * This is a protocol change, overload DRBD_FF_WSAME as flag
3358                  * for "new-enough" peer DRBD version. */
3359                 if (device->state.role == R_PRIMARY || peer_role == R_PRIMARY) {
3360                         *rule_nr = 41;
3361                         if (!(connection->agreed_features & DRBD_FF_WSAME)) {
3362                                 drbd_warn(peer_device, "Equivalent unrotated UUIDs, but current primary present.\n");
3363                                 return -(0x10000 | PRO_VERSION_MAX | (DRBD_FF_WSAME << 8));
3364                         }
3365                         if (device->state.role == R_PRIMARY && peer_role == R_PRIMARY) {
3366                                 /* At least one has the "crashed primary" bit set,
3367                                  * both are primary now, but neither has rotated its UUIDs?
3368                                  * "Can not happen." */
3369                                 drbd_err(peer_device, "Equivalent unrotated UUIDs, but both are primary. Can not resolve this.\n");
3370                                 return -100;
3371                         }
3372                         if (device->state.role == R_PRIMARY)
3373                                 return 1;
3374                         return -1;
3375                 }
3376
3377                 /* Both are secondary.
3378                  * Really looks like recovery from simultaneous hard crash.
3379                  * Check which had been primary before, and arbitrate. */
3380                 switch (rct) {
3381                 case 0: /* !self_pri && !peer_pri */ return 0; /* already handled */
3382                 case 1: /*  self_pri && !peer_pri */ return 1;
3383                 case 2: /* !self_pri &&  peer_pri */ return -1;
3384                 case 3: /*  self_pri &&  peer_pri */
3385                         dc = test_bit(RESOLVE_CONFLICTS, &connection->flags);
3386                         return dc ? -1 : 1;
3387                 }
3388         }
3389
3390         *rule_nr = 50;
3391         peer = device->p_uuid[UI_BITMAP] & ~((u64)1);
3392         if (self == peer)
3393                 return -1;
3394
3395         *rule_nr = 51;
3396         peer = device->p_uuid[UI_HISTORY_START] & ~((u64)1);
3397         if (self == peer) {
3398                 if (connection->agreed_pro_version < 96 ?
3399                     (device->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1)) ==
3400                     (device->p_uuid[UI_HISTORY_START + 1] & ~((u64)1)) :
3401                     peer + UUID_NEW_BM_OFFSET == (device->p_uuid[UI_BITMAP] & ~((u64)1))) {
3402                         /* The last P_SYNC_UUID did not get though. Undo the last start of
3403                            resync as sync source modifications of the peer's UUIDs. */
3404
3405                         if (connection->agreed_pro_version < 91)
3406                                 return -1091;
3407
3408                         device->p_uuid[UI_BITMAP] = device->p_uuid[UI_HISTORY_START];
3409                         device->p_uuid[UI_HISTORY_START] = device->p_uuid[UI_HISTORY_START + 1];
3410
3411                         drbd_info(device, "Lost last syncUUID packet, corrected:\n");
3412                         drbd_uuid_dump(device, "peer", device->p_uuid, device->p_uuid[UI_SIZE], device->p_uuid[UI_FLAGS]);
3413
3414                         return -1;
3415                 }
3416         }
3417
3418         *rule_nr = 60;
3419         self = device->ldev->md.uuid[UI_CURRENT] & ~((u64)1);
3420         for (i = UI_HISTORY_START; i <= UI_HISTORY_END; i++) {
3421                 peer = device->p_uuid[i] & ~((u64)1);
3422                 if (self == peer)
3423                         return -2;
3424         }
3425
3426         *rule_nr = 70;
3427         self = device->ldev->md.uuid[UI_BITMAP] & ~((u64)1);
3428         peer = device->p_uuid[UI_CURRENT] & ~((u64)1);
3429         if (self == peer)
3430                 return 1;
3431
3432         *rule_nr = 71;
3433         self = device->ldev->md.uuid[UI_HISTORY_START] & ~((u64)1);
3434         if (self == peer) {
3435                 if (connection->agreed_pro_version < 96 ?
3436                     (device->ldev->md.uuid[UI_HISTORY_START + 1] & ~((u64)1)) ==
3437                     (device->p_uuid[UI_HISTORY_START] & ~((u64)1)) :
3438                     self + UUID_NEW_BM_OFFSET == (device->ldev->md.uuid[UI_BITMAP] & ~((u64)1))) {
3439                         /* The last P_SYNC_UUID did not get though. Undo the last start of
3440                            resync as sync source modifications of our UUIDs. */
3441
3442                         if (connection->agreed_pro_version < 91)
3443                                 return -1091;
3444
3445                         __drbd_uuid_set(device, UI_BITMAP, device->ldev->md.uuid[UI_HISTORY_START]);
3446                         __drbd_uuid_set(device, UI_HISTORY_START, device->ldev->md.uuid[UI_HISTORY_START + 1]);
3447
3448                         drbd_info(device, "Last syncUUID did not get through, corrected:\n");
3449                         drbd_uuid_dump(device, "self", device->ldev->md.uuid,
3450                                        device->state.disk >= D_NEGOTIATING ? drbd_bm_total_weight(device) : 0, 0);
3451
3452                         return 1;
3453                 }
3454         }
3455
3456
3457         *rule_nr = 80;
3458         peer = device->p_uuid[UI_CURRENT] & ~((u64)1);
3459         for (i = UI_HISTORY_START; i <= UI_HISTORY_END; i++) {
3460                 self = device->ldev->md.uuid[i] & ~((u64)1);
3461                 if (self == peer)
3462                         return 2;
3463         }
3464
3465         *rule_nr = 90;
3466         self = device->ldev->md.uuid[UI_BITMAP] & ~((u64)1);
3467         peer = device->p_uuid[UI_BITMAP] & ~((u64)1);
3468         if (self == peer && self != ((u64)0))
3469                 return 100;
3470
3471         *rule_nr = 100;
3472         for (i = UI_HISTORY_START; i <= UI_HISTORY_END; i++) {
3473                 self = device->ldev->md.uuid[i] & ~((u64)1);
3474                 for (j = UI_HISTORY_START; j <= UI_HISTORY_END; j++) {
3475                         peer = device->p_uuid[j] & ~((u64)1);
3476                         if (self == peer)
3477                                 return -100;
3478                 }
3479         }
3480
3481         return -1000;
3482 }
3483
3484 /* drbd_sync_handshake() returns the new conn state on success, or
3485    CONN_MASK (-1) on failure.
3486  */
3487 static enum drbd_conns drbd_sync_handshake(struct drbd_peer_device *peer_device,
3488                                            enum drbd_role peer_role,
3489                                            enum drbd_disk_state peer_disk) __must_hold(local)
3490 {
3491         struct drbd_device *device = peer_device->device;
3492         enum drbd_conns rv = C_MASK;
3493         enum drbd_disk_state mydisk;
3494         struct net_conf *nc;
3495         int hg, rule_nr, rr_conflict, tentative, always_asbp;
3496
3497         mydisk = device->state.disk;
3498         if (mydisk == D_NEGOTIATING)
3499                 mydisk = device->new_state_tmp.disk;
3500
3501         drbd_info(device, "drbd_sync_handshake:\n");
3502
3503         spin_lock_irq(&device->ldev->md.uuid_lock);
3504         drbd_uuid_dump(device, "self", device->ldev->md.uuid, device->comm_bm_set, 0);
3505         drbd_uuid_dump(device, "peer", device->p_uuid,
3506                        device->p_uuid[UI_SIZE], device->p_uuid[UI_FLAGS]);
3507
3508         hg = drbd_uuid_compare(device, peer_role, &rule_nr);
3509         spin_unlock_irq(&device->ldev->md.uuid_lock);
3510
3511         drbd_info(device, "uuid_compare()=%d by rule %d\n", hg, rule_nr);
3512
3513         if (hg == -1000) {
3514                 drbd_alert(device, "Unrelated data, aborting!\n");
3515                 return C_MASK;
3516         }
3517         if (hg < -0x10000) {
3518                 int proto, fflags;
3519                 hg = -hg;
3520                 proto = hg & 0xff;
3521                 fflags = (hg >> 8) & 0xff;
3522                 drbd_alert(device, "To resolve this both sides have to support at least protocol %d and feature flags 0x%x\n",
3523                                         proto, fflags);
3524                 return C_MASK;
3525         }
3526         if (hg < -1000) {
3527                 drbd_alert(device, "To resolve this both sides have to support at least protocol %d\n", -hg - 1000);
3528                 return C_MASK;
3529         }
3530
3531         if    ((mydisk == D_INCONSISTENT && peer_disk > D_INCONSISTENT) ||
3532             (peer_disk == D_INCONSISTENT && mydisk    > D_INCONSISTENT)) {
3533                 int f = (hg == -100) || abs(hg) == 2;
3534                 hg = mydisk > D_INCONSISTENT ? 1 : -1;
3535                 if (f)
3536                         hg = hg*2;
3537                 drbd_info(device, "Becoming sync %s due to disk states.\n",
3538                      hg > 0 ? "source" : "target");
3539         }
3540
3541         if (abs(hg) == 100)
3542                 drbd_khelper(device, "initial-split-brain");
3543
3544         rcu_read_lock();
3545         nc = rcu_dereference(peer_device->connection->net_conf);
3546         always_asbp = nc->always_asbp;
3547         rr_conflict = nc->rr_conflict;
3548         tentative = nc->tentative;
3549         rcu_read_unlock();
3550
3551         if (hg == 100 || (hg == -100 && always_asbp)) {
3552                 int pcount = (device->state.role == R_PRIMARY)
3553                            + (peer_role == R_PRIMARY);
3554                 int forced = (hg == -100);
3555
3556                 switch (pcount) {
3557                 case 0:
3558                         hg = drbd_asb_recover_0p(peer_device);
3559                         break;
3560                 case 1:
3561                         hg = drbd_asb_recover_1p(peer_device);
3562                         break;
3563                 case 2:
3564                         hg = drbd_asb_recover_2p(peer_device);
3565                         break;
3566                 }
3567                 if (abs(hg) < 100) {
3568                         drbd_warn(device, "Split-Brain detected, %d primaries, "
3569                              "automatically solved. Sync from %s node\n",
3570                              pcount, (hg < 0) ? "peer" : "this");
3571                         if (forced) {
3572                                 drbd_warn(device, "Doing a full sync, since"
3573                                      " UUIDs where ambiguous.\n");
3574                                 hg = hg*2;
3575                         }
3576                 }
3577         }
3578
3579         if (hg == -100) {
3580                 if (test_bit(DISCARD_MY_DATA, &device->flags) && !(device->p_uuid[UI_FLAGS]&1))
3581                         hg = -1;
3582                 if (!test_bit(DISCARD_MY_DATA, &device->flags) && (device->p_uuid[UI_FLAGS]&1))
3583                         hg = 1;
3584
3585                 if (abs(hg) < 100)
3586                         drbd_warn(device, "Split-Brain detected, manually solved. "
3587                              "Sync from %s node\n",
3588                              (hg < 0) ? "peer" : "this");
3589         }
3590
3591         if (hg == -100) {
3592                 /* FIXME this log message is not correct if we end up here
3593                  * after an attempted attach on a diskless node.
3594                  * We just refuse to attach -- well, we drop the "connection"
3595                  * to that disk, in a way... */
3596                 drbd_alert(device, "Split-Brain detected but unresolved, dropping connection!\n");
3597                 drbd_khelper(device, "split-brain");
3598                 return C_MASK;
3599         }
3600
3601         if (hg > 0 && mydisk <= D_INCONSISTENT) {
3602                 drbd_err(device, "I shall become SyncSource, but I am inconsistent!\n");
3603                 return C_MASK;
3604         }
3605
3606         if (hg < 0 && /* by intention we do not use mydisk here. */
3607             device->state.role == R_PRIMARY && device->state.disk >= D_CONSISTENT) {
3608                 switch (rr_conflict) {
3609                 case ASB_CALL_HELPER:
3610                         drbd_khelper(device, "pri-lost");
3611                         fallthrough;
3612                 case ASB_DISCONNECT:
3613                         drbd_err(device, "I shall become SyncTarget, but I am primary!\n");
3614                         return C_MASK;
3615                 case ASB_VIOLENTLY:
3616                         drbd_warn(device, "Becoming SyncTarget, violating the stable-data"
3617                              "assumption\n");
3618                 }
3619         }
3620
3621         if (tentative || test_bit(CONN_DRY_RUN, &peer_device->connection->flags)) {
3622                 if (hg == 0)
3623                         drbd_info(device, "dry-run connect: No resync, would become Connected immediately.\n");
3624                 else
3625                         drbd_info(device, "dry-run connect: Would become %s, doing a %s resync.",
3626                                  drbd_conn_str(hg > 0 ? C_SYNC_SOURCE : C_SYNC_TARGET),
3627                                  abs(hg) >= 2 ? "full" : "bit-map based");
3628                 return C_MASK;
3629         }
3630
3631         if (abs(hg) >= 2) {
3632                 drbd_info(device, "Writing the whole bitmap, full sync required after drbd_sync_handshake.\n");
3633                 if (drbd_bitmap_io(device, &drbd_bmio_set_n_write, "set_n_write from sync_handshake",
3634                                         BM_LOCKED_SET_ALLOWED))
3635                         return C_MASK;
3636         }
3637
3638         if (hg > 0) { /* become sync source. */
3639                 rv = C_WF_BITMAP_S;
3640         } else if (hg < 0) { /* become sync target */
3641                 rv = C_WF_BITMAP_T;
3642         } else {
3643                 rv = C_CONNECTED;
3644                 if (drbd_bm_total_weight(device)) {
3645                         drbd_info(device, "No resync, but %lu bits in bitmap!\n",
3646                              drbd_bm_total_weight(device));
3647                 }
3648         }
3649
3650         return rv;
3651 }
3652
3653 static enum drbd_after_sb_p convert_after_sb(enum drbd_after_sb_p peer)
3654 {
3655         /* ASB_DISCARD_REMOTE - ASB_DISCARD_LOCAL is valid */
3656         if (peer == ASB_DISCARD_REMOTE)
3657                 return ASB_DISCARD_LOCAL;
3658
3659         /* any other things with ASB_DISCARD_REMOTE or ASB_DISCARD_LOCAL are invalid */
3660         if (peer == ASB_DISCARD_LOCAL)
3661                 return ASB_DISCARD_REMOTE;
3662
3663         /* everything else is valid if they are equal on both sides. */
3664         return peer;
3665 }
3666
3667 static int receive_protocol(struct drbd_connection *connection, struct packet_info *pi)
3668 {
3669         struct p_protocol *p = pi->data;
3670         enum drbd_after_sb_p p_after_sb_0p, p_after_sb_1p, p_after_sb_2p;
3671         int p_proto, p_discard_my_data, p_two_primaries, cf;
3672         struct net_conf *nc, *old_net_conf, *new_net_conf = NULL;
3673         char integrity_alg[SHARED_SECRET_MAX] = "";
3674         struct crypto_shash *peer_integrity_tfm = NULL;
3675         void *int_dig_in = NULL, *int_dig_vv = NULL;
3676
3677         p_proto         = be32_to_cpu(p->protocol);
3678         p_after_sb_0p   = be32_to_cpu(p->after_sb_0p);
3679         p_after_sb_1p   = be32_to_cpu(p->after_sb_1p);
3680         p_after_sb_2p   = be32_to_cpu(p->after_sb_2p);
3681         p_two_primaries = be32_to_cpu(p->two_primaries);
3682         cf              = be32_to_cpu(p->conn_flags);
3683         p_discard_my_data = cf & CF_DISCARD_MY_DATA;
3684
3685         if (connection->agreed_pro_version >= 87) {
3686                 int err;
3687
3688                 if (pi->size > sizeof(integrity_alg))
3689                         return -EIO;
3690                 err = drbd_recv_all(connection, integrity_alg, pi->size);
3691                 if (err)
3692                         return err;
3693                 integrity_alg[SHARED_SECRET_MAX - 1] = 0;
3694         }
3695
3696         if (pi->cmd != P_PROTOCOL_UPDATE) {
3697                 clear_bit(CONN_DRY_RUN, &connection->flags);
3698
3699                 if (cf & CF_DRY_RUN)
3700                         set_bit(CONN_DRY_RUN, &connection->flags);
3701
3702                 rcu_read_lock();
3703                 nc = rcu_dereference(connection->net_conf);
3704
3705                 if (p_proto != nc->wire_protocol) {
3706                         drbd_err(connection, "incompatible %s settings\n", "protocol");
3707                         goto disconnect_rcu_unlock;
3708                 }
3709
3710                 if (convert_after_sb(p_after_sb_0p) != nc->after_sb_0p) {
3711                         drbd_err(connection, "incompatible %s settings\n", "after-sb-0pri");
3712                         goto disconnect_rcu_unlock;
3713                 }
3714
3715                 if (convert_after_sb(p_after_sb_1p) != nc->after_sb_1p) {
3716                         drbd_err(connection, "incompatible %s settings\n", "after-sb-1pri");
3717                         goto disconnect_rcu_unlock;
3718                 }
3719
3720                 if (convert_after_sb(p_after_sb_2p) != nc->after_sb_2p) {
3721                         drbd_err(connection, "incompatible %s settings\n", "after-sb-2pri");
3722                         goto disconnect_rcu_unlock;
3723                 }
3724
3725                 if (p_discard_my_data && nc->discard_my_data) {
3726                         drbd_err(connection, "incompatible %s settings\n", "discard-my-data");
3727                         goto disconnect_rcu_unlock;
3728                 }
3729
3730                 if (p_two_primaries != nc->two_primaries) {
3731                         drbd_err(connection, "incompatible %s settings\n", "allow-two-primaries");
3732                         goto disconnect_rcu_unlock;
3733                 }
3734
3735                 if (strcmp(integrity_alg, nc->integrity_alg)) {
3736                         drbd_err(connection, "incompatible %s settings\n", "data-integrity-alg");
3737                         goto disconnect_rcu_unlock;
3738                 }
3739
3740                 rcu_read_unlock();
3741         }
3742
3743         if (integrity_alg[0]) {
3744                 int hash_size;
3745
3746                 /*
3747                  * We can only change the peer data integrity algorithm
3748                  * here.  Changing our own data integrity algorithm
3749                  * requires that we send a P_PROTOCOL_UPDATE packet at
3750                  * the same time; otherwise, the peer has no way to
3751                  * tell between which packets the algorithm should
3752                  * change.
3753                  */
3754
3755                 peer_integrity_tfm = crypto_alloc_shash(integrity_alg, 0, 0);
3756                 if (IS_ERR(peer_integrity_tfm)) {
3757                         peer_integrity_tfm = NULL;
3758                         drbd_err(connection, "peer data-integrity-alg %s not supported\n",
3759                                  integrity_alg);
3760                         goto disconnect;
3761                 }
3762
3763                 hash_size = crypto_shash_digestsize(peer_integrity_tfm);
3764                 int_dig_in = kmalloc(hash_size, GFP_KERNEL);
3765                 int_dig_vv = kmalloc(hash_size, GFP_KERNEL);
3766                 if (!(int_dig_in && int_dig_vv)) {
3767                         drbd_err(connection, "Allocation of buffers for data integrity checking failed\n");
3768                         goto disconnect;
3769                 }
3770         }
3771
3772         new_net_conf = kmalloc(sizeof(struct net_conf), GFP_KERNEL);
3773         if (!new_net_conf)
3774                 goto disconnect;
3775
3776         mutex_lock(&connection->data.mutex);
3777         mutex_lock(&connection->resource->conf_update);
3778         old_net_conf = connection->net_conf;
3779         *new_net_conf = *old_net_conf;
3780
3781         new_net_conf->wire_protocol = p_proto;
3782         new_net_conf->after_sb_0p = convert_after_sb(p_after_sb_0p);
3783         new_net_conf->after_sb_1p = convert_after_sb(p_after_sb_1p);
3784         new_net_conf->after_sb_2p = convert_after_sb(p_after_sb_2p);
3785         new_net_conf->two_primaries = p_two_primaries;
3786
3787         rcu_assign_pointer(connection->net_conf, new_net_conf);
3788         mutex_unlock(&connection->resource->conf_update);
3789         mutex_unlock(&connection->data.mutex);
3790
3791         crypto_free_shash(connection->peer_integrity_tfm);
3792         kfree(connection->int_dig_in);
3793         kfree(connection->int_dig_vv);
3794         connection->peer_integrity_tfm = peer_integrity_tfm;
3795         connection->int_dig_in = int_dig_in;
3796         connection->int_dig_vv = int_dig_vv;
3797
3798         if (strcmp(old_net_conf->integrity_alg, integrity_alg))
3799                 drbd_info(connection, "peer data-integrity-alg: %s\n",
3800                           integrity_alg[0] ? integrity_alg : "(none)");
3801
3802         synchronize_rcu();
3803         kfree(old_net_conf);
3804         return 0;
3805
3806 disconnect_rcu_unlock:
3807         rcu_read_unlock();
3808 disconnect:
3809         crypto_free_shash(peer_integrity_tfm);
3810         kfree(int_dig_in);
3811         kfree(int_dig_vv);
3812         conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_HARD);
3813         return -EIO;
3814 }
3815
3816 /* helper function
3817  * input: alg name, feature name
3818  * return: NULL (alg name was "")
3819  *         ERR_PTR(error) if something goes wrong
3820  *         or the crypto hash ptr, if it worked out ok. */
3821 static struct crypto_shash *drbd_crypto_alloc_digest_safe(
3822                 const struct drbd_device *device,
3823                 const char *alg, const char *name)
3824 {
3825         struct crypto_shash *tfm;
3826
3827         if (!alg[0])
3828                 return NULL;
3829
3830         tfm = crypto_alloc_shash(alg, 0, 0);
3831         if (IS_ERR(tfm)) {
3832                 drbd_err(device, "Can not allocate \"%s\" as %s (reason: %ld)\n",
3833                         alg, name, PTR_ERR(tfm));
3834                 return tfm;
3835         }
3836         return tfm;
3837 }
3838
3839 static int ignore_remaining_packet(struct drbd_connection *connection, struct packet_info *pi)
3840 {
3841         void *buffer = connection->data.rbuf;
3842         int size = pi->size;
3843
3844         while (size) {
3845                 int s = min_t(int, size, DRBD_SOCKET_BUFFER_SIZE);
3846                 s = drbd_recv(connection, buffer, s);
3847                 if (s <= 0) {
3848                         if (s < 0)
3849                                 return s;
3850                         break;
3851                 }
3852                 size -= s;
3853         }
3854         if (size)
3855                 return -EIO;
3856         return 0;
3857 }
3858
3859 /*
3860  * config_unknown_volume  -  device configuration command for unknown volume
3861  *
3862  * When a device is added to an existing connection, the node on which the
3863  * device is added first will send configuration commands to its peer but the
3864  * peer will not know about the device yet.  It will warn and ignore these
3865  * commands.  Once the device is added on the second node, the second node will
3866  * send the same device configuration commands, but in the other direction.
3867  *
3868  * (We can also end up here if drbd is misconfigured.)
3869  */
3870 static int config_unknown_volume(struct drbd_connection *connection, struct packet_info *pi)
3871 {
3872         drbd_warn(connection, "%s packet received for volume %u, which is not configured locally\n",
3873                   cmdname(pi->cmd), pi->vnr);
3874         return ignore_remaining_packet(connection, pi);
3875 }
3876
3877 static int receive_SyncParam(struct drbd_connection *connection, struct packet_info *pi)
3878 {
3879         struct drbd_peer_device *peer_device;
3880         struct drbd_device *device;
3881         struct p_rs_param_95 *p;
3882         unsigned int header_size, data_size, exp_max_sz;
3883         struct crypto_shash *verify_tfm = NULL;
3884         struct crypto_shash *csums_tfm = NULL;
3885         struct net_conf *old_net_conf, *new_net_conf = NULL;
3886         struct disk_conf *old_disk_conf = NULL, *new_disk_conf = NULL;
3887         const int apv = connection->agreed_pro_version;
3888         struct fifo_buffer *old_plan = NULL, *new_plan = NULL;
3889         unsigned int fifo_size = 0;
3890         int err;
3891
3892         peer_device = conn_peer_device(connection, pi->vnr);
3893         if (!peer_device)
3894                 return config_unknown_volume(connection, pi);
3895         device = peer_device->device;
3896
3897         exp_max_sz  = apv <= 87 ? sizeof(struct p_rs_param)
3898                     : apv == 88 ? sizeof(struct p_rs_param)
3899                                         + SHARED_SECRET_MAX
3900                     : apv <= 94 ? sizeof(struct p_rs_param_89)
3901                     : /* apv >= 95 */ sizeof(struct p_rs_param_95);
3902
3903         if (pi->size > exp_max_sz) {
3904                 drbd_err(device, "SyncParam packet too long: received %u, expected <= %u bytes\n",
3905                     pi->size, exp_max_sz);
3906                 return -EIO;
3907         }
3908
3909         if (apv <= 88) {
3910                 header_size = sizeof(struct p_rs_param);
3911                 data_size = pi->size - header_size;
3912         } else if (apv <= 94) {
3913                 header_size = sizeof(struct p_rs_param_89);
3914                 data_size = pi->size - header_size;
3915                 D_ASSERT(device, data_size == 0);
3916         } else {
3917                 header_size = sizeof(struct p_rs_param_95);
3918                 data_size = pi->size - header_size;
3919                 D_ASSERT(device, data_size == 0);
3920         }
3921
3922         /* initialize verify_alg and csums_alg */
3923         p = pi->data;
3924         memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
3925
3926         err = drbd_recv_all(peer_device->connection, p, header_size);
3927         if (err)
3928                 return err;
3929
3930         mutex_lock(&connection->resource->conf_update);
3931         old_net_conf = peer_device->connection->net_conf;
3932         if (get_ldev(device)) {
3933                 new_disk_conf = kzalloc(sizeof(struct disk_conf), GFP_KERNEL);
3934                 if (!new_disk_conf) {
3935                         put_ldev(device);
3936                         mutex_unlock(&connection->resource->conf_update);
3937                         drbd_err(device, "Allocation of new disk_conf failed\n");
3938                         return -ENOMEM;
3939                 }
3940
3941                 old_disk_conf = device->ldev->disk_conf;
3942                 *new_disk_conf = *old_disk_conf;
3943
3944                 new_disk_conf->resync_rate = be32_to_cpu(p->resync_rate);
3945         }
3946
3947         if (apv >= 88) {
3948                 if (apv == 88) {
3949                         if (data_size > SHARED_SECRET_MAX || data_size == 0) {
3950                                 drbd_err(device, "verify-alg of wrong size, "
3951                                         "peer wants %u, accepting only up to %u byte\n",
3952                                         data_size, SHARED_SECRET_MAX);
3953                                 err = -EIO;
3954                                 goto reconnect;
3955                         }
3956
3957                         err = drbd_recv_all(peer_device->connection, p->verify_alg, data_size);
3958                         if (err)
3959                                 goto reconnect;
3960                         /* we expect NUL terminated string */
3961                         /* but just in case someone tries to be evil */
3962                         D_ASSERT(device, p->verify_alg[data_size-1] == 0);
3963                         p->verify_alg[data_size-1] = 0;
3964
3965                 } else /* apv >= 89 */ {
3966                         /* we still expect NUL terminated strings */
3967                         /* but just in case someone tries to be evil */
3968                         D_ASSERT(device, p->verify_alg[SHARED_SECRET_MAX-1] == 0);
3969                         D_ASSERT(device, p->csums_alg[SHARED_SECRET_MAX-1] == 0);
3970                         p->verify_alg[SHARED_SECRET_MAX-1] = 0;
3971                         p->csums_alg[SHARED_SECRET_MAX-1] = 0;
3972                 }
3973
3974                 if (strcmp(old_net_conf->verify_alg, p->verify_alg)) {
3975                         if (device->state.conn == C_WF_REPORT_PARAMS) {
3976                                 drbd_err(device, "Different verify-alg settings. me=\"%s\" peer=\"%s\"\n",
3977                                     old_net_conf->verify_alg, p->verify_alg);
3978                                 goto disconnect;
3979                         }
3980                         verify_tfm = drbd_crypto_alloc_digest_safe(device,
3981                                         p->verify_alg, "verify-alg");
3982                         if (IS_ERR(verify_tfm)) {
3983                                 verify_tfm = NULL;
3984                                 goto disconnect;
3985                         }
3986                 }
3987
3988                 if (apv >= 89 && strcmp(old_net_conf->csums_alg, p->csums_alg)) {
3989                         if (device->state.conn == C_WF_REPORT_PARAMS) {
3990                                 drbd_err(device, "Different csums-alg settings. me=\"%s\" peer=\"%s\"\n",
3991                                     old_net_conf->csums_alg, p->csums_alg);
3992                                 goto disconnect;
3993                         }
3994                         csums_tfm = drbd_crypto_alloc_digest_safe(device,
3995                                         p->csums_alg, "csums-alg");
3996                         if (IS_ERR(csums_tfm)) {
3997                                 csums_tfm = NULL;
3998                                 goto disconnect;
3999                         }
4000                 }
4001
4002                 if (apv > 94 && new_disk_conf) {
4003                         new_disk_conf->c_plan_ahead = be32_to_cpu(p->c_plan_ahead);
4004                         new_disk_conf->c_delay_target = be32_to_cpu(p->c_delay_target);
4005                         new_disk_conf->c_fill_target = be32_to_cpu(p->c_fill_target);
4006                         new_disk_conf->c_max_rate = be32_to_cpu(p->c_max_rate);
4007
4008                         fifo_size = (new_disk_conf->c_plan_ahead * 10 * SLEEP_TIME) / HZ;
4009                         if (fifo_size != device->rs_plan_s->size) {
4010                                 new_plan = fifo_alloc(fifo_size);
4011                                 if (!new_plan) {
4012                                         drbd_err(device, "kmalloc of fifo_buffer failed");
4013                                         put_ldev(device);
4014                                         goto disconnect;
4015                                 }
4016                         }
4017                 }
4018
4019                 if (verify_tfm || csums_tfm) {
4020                         new_net_conf = kzalloc(sizeof(struct net_conf), GFP_KERNEL);
4021                         if (!new_net_conf)
4022                                 goto disconnect;
4023
4024                         *new_net_conf = *old_net_conf;
4025
4026                         if (verify_tfm) {
4027                                 strcpy(new_net_conf->verify_alg, p->verify_alg);
4028                                 new_net_conf->verify_alg_len = strlen(p->verify_alg) + 1;
4029                                 crypto_free_shash(peer_device->connection->verify_tfm);
4030                                 peer_device->connection->verify_tfm = verify_tfm;
4031                                 drbd_info(device, "using verify-alg: \"%s\"\n", p->verify_alg);
4032                         }
4033                         if (csums_tfm) {
4034                                 strcpy(new_net_conf->csums_alg, p->csums_alg);
4035                                 new_net_conf->csums_alg_len = strlen(p->csums_alg) + 1;
4036                                 crypto_free_shash(peer_device->connection->csums_tfm);
4037                                 peer_device->connection->csums_tfm = csums_tfm;
4038                                 drbd_info(device, "using csums-alg: \"%s\"\n", p->csums_alg);
4039                         }
4040                         rcu_assign_pointer(connection->net_conf, new_net_conf);
4041                 }
4042         }
4043
4044         if (new_disk_conf) {
4045                 rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
4046                 put_ldev(device);
4047         }
4048
4049         if (new_plan) {
4050                 old_plan = device->rs_plan_s;
4051                 rcu_assign_pointer(device->rs_plan_s, new_plan);
4052         }
4053
4054         mutex_unlock(&connection->resource->conf_update);
4055         synchronize_rcu();
4056         if (new_net_conf)
4057                 kfree(old_net_conf);
4058         kfree(old_disk_conf);
4059         kfree(old_plan);
4060
4061         return 0;
4062
4063 reconnect:
4064         if (new_disk_conf) {
4065                 put_ldev(device);
4066                 kfree(new_disk_conf);
4067         }
4068         mutex_unlock(&connection->resource->conf_update);
4069         return -EIO;
4070
4071 disconnect:
4072         kfree(new_plan);
4073         if (new_disk_conf) {
4074                 put_ldev(device);
4075                 kfree(new_disk_conf);
4076         }
4077         mutex_unlock(&connection->resource->conf_update);
4078         /* just for completeness: actually not needed,
4079          * as this is not reached if csums_tfm was ok. */
4080         crypto_free_shash(csums_tfm);
4081         /* but free the verify_tfm again, if csums_tfm did not work out */
4082         crypto_free_shash(verify_tfm);
4083         conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD);
4084         return -EIO;
4085 }
4086
4087 /* warn if the arguments differ by more than 12.5% */
4088 static void warn_if_differ_considerably(struct drbd_device *device,
4089         const char *s, sector_t a, sector_t b)
4090 {
4091         sector_t d;
4092         if (a == 0 || b == 0)
4093                 return;
4094         d = (a > b) ? (a - b) : (b - a);
4095         if (d > (a>>3) || d > (b>>3))
4096                 drbd_warn(device, "Considerable difference in %s: %llus vs. %llus\n", s,
4097                      (unsigned long long)a, (unsigned long long)b);
4098 }
4099
4100 static int receive_sizes(struct drbd_connection *connection, struct packet_info *pi)
4101 {
4102         struct drbd_peer_device *peer_device;
4103         struct drbd_device *device;
4104         struct p_sizes *p = pi->data;
4105         struct o_qlim *o = (connection->agreed_features & DRBD_FF_WSAME) ? p->qlim : NULL;
4106         enum determine_dev_size dd = DS_UNCHANGED;
4107         sector_t p_size, p_usize, p_csize, my_usize;
4108         sector_t new_size, cur_size;
4109         int ldsc = 0; /* local disk size changed */
4110         enum dds_flags ddsf;
4111
4112         peer_device = conn_peer_device(connection, pi->vnr);
4113         if (!peer_device)
4114                 return config_unknown_volume(connection, pi);
4115         device = peer_device->device;
4116         cur_size = get_capacity(device->vdisk);
4117
4118         p_size = be64_to_cpu(p->d_size);
4119         p_usize = be64_to_cpu(p->u_size);
4120         p_csize = be64_to_cpu(p->c_size);
4121
4122         /* just store the peer's disk size for now.
4123          * we still need to figure out whether we accept that. */
4124         device->p_size = p_size;
4125
4126         if (get_ldev(device)) {
4127                 rcu_read_lock();
4128                 my_usize = rcu_dereference(device->ldev->disk_conf)->disk_size;
4129                 rcu_read_unlock();
4130
4131                 warn_if_differ_considerably(device, "lower level device sizes",
4132                            p_size, drbd_get_max_capacity(device->ldev));
4133                 warn_if_differ_considerably(device, "user requested size",
4134                                             p_usize, my_usize);
4135
4136                 /* if this is the first connect, or an otherwise expected
4137                  * param exchange, choose the minimum */
4138                 if (device->state.conn == C_WF_REPORT_PARAMS)
4139                         p_usize = min_not_zero(my_usize, p_usize);
4140
4141                 /* Never shrink a device with usable data during connect,
4142                  * or "attach" on the peer.
4143                  * But allow online shrinking if we are connected. */
4144                 new_size = drbd_new_dev_size(device, device->ldev, p_usize, 0);
4145                 if (new_size < cur_size &&
4146                     device->state.disk >= D_OUTDATED &&
4147                     (device->state.conn < C_CONNECTED || device->state.pdsk == D_DISKLESS)) {
4148                         drbd_err(device, "The peer's disk size is too small! (%llu < %llu sectors)\n",
4149                                         (unsigned long long)new_size, (unsigned long long)cur_size);
4150                         conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD);
4151                         put_ldev(device);
4152                         return -EIO;
4153                 }
4154
4155                 if (my_usize != p_usize) {
4156                         struct disk_conf *old_disk_conf, *new_disk_conf = NULL;
4157
4158                         new_disk_conf = kzalloc(sizeof(struct disk_conf), GFP_KERNEL);
4159                         if (!new_disk_conf) {
4160                                 put_ldev(device);
4161                                 return -ENOMEM;
4162                         }
4163
4164                         mutex_lock(&connection->resource->conf_update);
4165                         old_disk_conf = device->ldev->disk_conf;
4166                         *new_disk_conf = *old_disk_conf;
4167                         new_disk_conf->disk_size = p_usize;
4168
4169                         rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
4170                         mutex_unlock(&connection->resource->conf_update);
4171                         synchronize_rcu();
4172                         kfree(old_disk_conf);
4173
4174                         drbd_info(device, "Peer sets u_size to %lu sectors (old: %lu)\n",
4175                                  (unsigned long)p_usize, (unsigned long)my_usize);
4176                 }
4177
4178                 put_ldev(device);
4179         }
4180
4181         device->peer_max_bio_size = be32_to_cpu(p->max_bio_size);
4182         /* Leave drbd_reconsider_queue_parameters() before drbd_determine_dev_size().
4183            In case we cleared the QUEUE_FLAG_DISCARD from our queue in
4184            drbd_reconsider_queue_parameters(), we can be sure that after
4185            drbd_determine_dev_size() no REQ_DISCARDs are in the queue. */
4186
4187         ddsf = be16_to_cpu(p->dds_flags);
4188         if (get_ldev(device)) {
4189                 drbd_reconsider_queue_parameters(device, device->ldev, o);
4190                 dd = drbd_determine_dev_size(device, ddsf, NULL);
4191                 put_ldev(device);
4192                 if (dd == DS_ERROR)
4193                         return -EIO;
4194                 drbd_md_sync(device);
4195         } else {
4196                 /*
4197                  * I am diskless, need to accept the peer's *current* size.
4198                  * I must NOT accept the peers backing disk size,
4199                  * it may have been larger than mine all along...
4200                  *
4201                  * At this point, the peer knows more about my disk, or at
4202                  * least about what we last agreed upon, than myself.
4203                  * So if his c_size is less than his d_size, the most likely
4204                  * reason is that *my* d_size was smaller last time we checked.
4205                  *
4206                  * However, if he sends a zero current size,
4207                  * take his (user-capped or) backing disk size anyways.
4208                  *
4209                  * Unless of course he does not have a disk himself.
4210                  * In which case we ignore this completely.
4211                  */
4212                 sector_t new_size = p_csize ?: p_usize ?: p_size;
4213                 drbd_reconsider_queue_parameters(device, NULL, o);
4214                 if (new_size == 0) {
4215                         /* Ignore, peer does not know nothing. */
4216                 } else if (new_size == cur_size) {
4217                         /* nothing to do */
4218                 } else if (cur_size != 0 && p_size == 0) {
4219                         drbd_warn(device, "Ignored diskless peer device size (peer:%llu != me:%llu sectors)!\n",
4220                                         (unsigned long long)new_size, (unsigned long long)cur_size);
4221                 } else if (new_size < cur_size && device->state.role == R_PRIMARY) {
4222                         drbd_err(device, "The peer's device size is too small! (%llu < %llu sectors); demote me first!\n",
4223                                         (unsigned long long)new_size, (unsigned long long)cur_size);
4224                         conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD);
4225                         return -EIO;
4226                 } else {
4227                         /* I believe the peer, if
4228                          *  - I don't have a current size myself
4229                          *  - we agree on the size anyways
4230                          *  - I do have a current size, am Secondary,
4231                          *    and he has the only disk
4232                          *  - I do have a current size, am Primary,
4233                          *    and he has the only disk,
4234                          *    which is larger than my current size
4235                          */
4236                         drbd_set_my_capacity(device, new_size);
4237                 }
4238         }
4239
4240         if (get_ldev(device)) {
4241                 if (device->ldev->known_size != drbd_get_capacity(device->ldev->backing_bdev)) {
4242                         device->ldev->known_size = drbd_get_capacity(device->ldev->backing_bdev);
4243                         ldsc = 1;
4244                 }
4245
4246                 put_ldev(device);
4247         }
4248
4249         if (device->state.conn > C_WF_REPORT_PARAMS) {
4250                 if (be64_to_cpu(p->c_size) != get_capacity(device->vdisk) ||
4251                     ldsc) {
4252                         /* we have different sizes, probably peer
4253                          * needs to know my new size... */
4254                         drbd_send_sizes(peer_device, 0, ddsf);
4255                 }
4256                 if (test_and_clear_bit(RESIZE_PENDING, &device->flags) ||
4257                     (dd == DS_GREW && device->state.conn == C_CONNECTED)) {
4258                         if (device->state.pdsk >= D_INCONSISTENT &&
4259                             device->state.disk >= D_INCONSISTENT) {
4260                                 if (ddsf & DDSF_NO_RESYNC)
4261                                         drbd_info(device, "Resync of new storage suppressed with --assume-clean\n");
4262                                 else
4263                                         resync_after_online_grow(device);
4264                         } else
4265                                 set_bit(RESYNC_AFTER_NEG, &device->flags);
4266                 }
4267         }
4268
4269         return 0;
4270 }
4271
4272 static int receive_uuids(struct drbd_connection *connection, struct packet_info *pi)
4273 {
4274         struct drbd_peer_device *peer_device;
4275         struct drbd_device *device;
4276         struct p_uuids *p = pi->data;
4277         u64 *p_uuid;
4278         int i, updated_uuids = 0;
4279
4280         peer_device = conn_peer_device(connection, pi->vnr);
4281         if (!peer_device)
4282                 return config_unknown_volume(connection, pi);
4283         device = peer_device->device;
4284
4285         p_uuid = kmalloc_array(UI_EXTENDED_SIZE, sizeof(*p_uuid), GFP_NOIO);
4286         if (!p_uuid)
4287                 return false;
4288
4289         for (i = UI_CURRENT; i < UI_EXTENDED_SIZE; i++)
4290                 p_uuid[i] = be64_to_cpu(p->uuid[i]);
4291
4292         kfree(device->p_uuid);
4293         device->p_uuid = p_uuid;
4294
4295         if ((device->state.conn < C_CONNECTED || device->state.pdsk == D_DISKLESS) &&
4296             device->state.disk < D_INCONSISTENT &&
4297             device->state.role == R_PRIMARY &&
4298             (device->ed_uuid & ~((u64)1)) != (p_uuid[UI_CURRENT] & ~((u64)1))) {
4299                 drbd_err(device, "Can only connect to data with current UUID=%016llX\n",
4300                     (unsigned long long)device->ed_uuid);
4301                 conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD);
4302                 return -EIO;
4303         }
4304
4305         if (get_ldev(device)) {
4306                 int skip_initial_sync =
4307                         device->state.conn == C_CONNECTED &&
4308                         peer_device->connection->agreed_pro_version >= 90 &&
4309                         device->ldev->md.uuid[UI_CURRENT] == UUID_JUST_CREATED &&
4310                         (p_uuid[UI_FLAGS] & 8);
4311                 if (skip_initial_sync) {
4312                         drbd_info(device, "Accepted new current UUID, preparing to skip initial sync\n");
4313                         drbd_bitmap_io(device, &drbd_bmio_clear_n_write,
4314                                         "clear_n_write from receive_uuids",
4315                                         BM_LOCKED_TEST_ALLOWED);
4316                         _drbd_uuid_set(device, UI_CURRENT, p_uuid[UI_CURRENT]);
4317                         _drbd_uuid_set(device, UI_BITMAP, 0);
4318                         _drbd_set_state(_NS2(device, disk, D_UP_TO_DATE, pdsk, D_UP_TO_DATE),
4319                                         CS_VERBOSE, NULL);
4320                         drbd_md_sync(device);
4321                         updated_uuids = 1;
4322                 }
4323                 put_ldev(device);
4324         } else if (device->state.disk < D_INCONSISTENT &&
4325                    device->state.role == R_PRIMARY) {
4326                 /* I am a diskless primary, the peer just created a new current UUID
4327                    for me. */
4328                 updated_uuids = drbd_set_ed_uuid(device, p_uuid[UI_CURRENT]);
4329         }
4330
4331         /* Before we test for the disk state, we should wait until an eventually
4332            ongoing cluster wide state change is finished. That is important if
4333            we are primary and are detaching from our disk. We need to see the
4334            new disk state... */
4335         mutex_lock(device->state_mutex);
4336         mutex_unlock(device->state_mutex);
4337         if (device->state.conn >= C_CONNECTED && device->state.disk < D_INCONSISTENT)
4338                 updated_uuids |= drbd_set_ed_uuid(device, p_uuid[UI_CURRENT]);
4339
4340         if (updated_uuids)
4341                 drbd_print_uuids(device, "receiver updated UUIDs to");
4342
4343         return 0;
4344 }
4345
4346 /**
4347  * convert_state() - Converts the peer's view of the cluster state to our point of view
4348  * @ps:         The state as seen by the peer.
4349  */
4350 static union drbd_state convert_state(union drbd_state ps)
4351 {
4352         union drbd_state ms;
4353
4354         static enum drbd_conns c_tab[] = {
4355                 [C_WF_REPORT_PARAMS] = C_WF_REPORT_PARAMS,
4356                 [C_CONNECTED] = C_CONNECTED,
4357
4358                 [C_STARTING_SYNC_S] = C_STARTING_SYNC_T,
4359                 [C_STARTING_SYNC_T] = C_STARTING_SYNC_S,
4360                 [C_DISCONNECTING] = C_TEAR_DOWN, /* C_NETWORK_FAILURE, */
4361                 [C_VERIFY_S]       = C_VERIFY_T,
4362                 [C_MASK]   = C_MASK,
4363         };
4364
4365         ms.i = ps.i;
4366
4367         ms.conn = c_tab[ps.conn];
4368         ms.peer = ps.role;
4369         ms.role = ps.peer;
4370         ms.pdsk = ps.disk;
4371         ms.disk = ps.pdsk;
4372         ms.peer_isp = (ps.aftr_isp | ps.user_isp);
4373
4374         return ms;
4375 }
4376
4377 static int receive_req_state(struct drbd_connection *connection, struct packet_info *pi)
4378 {
4379         struct drbd_peer_device *peer_device;
4380         struct drbd_device *device;
4381         struct p_req_state *p = pi->data;
4382         union drbd_state mask, val;
4383         enum drbd_state_rv rv;
4384
4385         peer_device = conn_peer_device(connection, pi->vnr);
4386         if (!peer_device)
4387                 return -EIO;
4388         device = peer_device->device;
4389
4390         mask.i = be32_to_cpu(p->mask);
4391         val.i = be32_to_cpu(p->val);
4392
4393         if (test_bit(RESOLVE_CONFLICTS, &peer_device->connection->flags) &&
4394             mutex_is_locked(device->state_mutex)) {
4395                 drbd_send_sr_reply(peer_device, SS_CONCURRENT_ST_CHG);
4396                 return 0;
4397         }
4398
4399         mask = convert_state(mask);
4400         val = convert_state(val);
4401
4402         rv = drbd_change_state(device, CS_VERBOSE, mask, val);
4403         drbd_send_sr_reply(peer_device, rv);
4404
4405         drbd_md_sync(device);
4406
4407         return 0;
4408 }
4409
4410 static int receive_req_conn_state(struct drbd_connection *connection, struct packet_info *pi)
4411 {
4412         struct p_req_state *p = pi->data;
4413         union drbd_state mask, val;
4414         enum drbd_state_rv rv;
4415
4416         mask.i = be32_to_cpu(p->mask);
4417         val.i = be32_to_cpu(p->val);
4418
4419         if (test_bit(RESOLVE_CONFLICTS, &connection->flags) &&
4420             mutex_is_locked(&connection->cstate_mutex)) {
4421                 conn_send_sr_reply(connection, SS_CONCURRENT_ST_CHG);
4422                 return 0;
4423         }
4424
4425         mask = convert_state(mask);
4426         val = convert_state(val);
4427
4428         rv = conn_request_state(connection, mask, val, CS_VERBOSE | CS_LOCAL_ONLY | CS_IGN_OUTD_FAIL);
4429         conn_send_sr_reply(connection, rv);
4430
4431         return 0;
4432 }
4433
4434 static int receive_state(struct drbd_connection *connection, struct packet_info *pi)
4435 {
4436         struct drbd_peer_device *peer_device;
4437         struct drbd_device *device;
4438         struct p_state *p = pi->data;
4439         union drbd_state os, ns, peer_state;
4440         enum drbd_disk_state real_peer_disk;
4441         enum chg_state_flags cs_flags;
4442         int rv;
4443
4444         peer_device = conn_peer_device(connection, pi->vnr);
4445         if (!peer_device)
4446                 return config_unknown_volume(connection, pi);
4447         device = peer_device->device;
4448
4449         peer_state.i = be32_to_cpu(p->state);
4450
4451         real_peer_disk = peer_state.disk;
4452         if (peer_state.disk == D_NEGOTIATING) {
4453                 real_peer_disk = device->p_uuid[UI_FLAGS] & 4 ? D_INCONSISTENT : D_CONSISTENT;
4454                 drbd_info(device, "real peer disk state = %s\n", drbd_disk_str(real_peer_disk));
4455         }
4456
4457         spin_lock_irq(&device->resource->req_lock);
4458  retry:
4459         os = ns = drbd_read_state(device);
4460         spin_unlock_irq(&device->resource->req_lock);
4461
4462         /* If some other part of the code (ack_receiver thread, timeout)
4463          * already decided to close the connection again,
4464          * we must not "re-establish" it here. */
4465         if (os.conn <= C_TEAR_DOWN)
4466                 return -ECONNRESET;
4467
4468         /* If this is the "end of sync" confirmation, usually the peer disk
4469          * transitions from D_INCONSISTENT to D_UP_TO_DATE. For empty (0 bits
4470          * set) resync started in PausedSyncT, or if the timing of pause-/
4471          * unpause-sync events has been "just right", the peer disk may
4472          * transition from D_CONSISTENT to D_UP_TO_DATE as well.
4473          */
4474         if ((os.pdsk == D_INCONSISTENT || os.pdsk == D_CONSISTENT) &&
4475             real_peer_disk == D_UP_TO_DATE &&
4476             os.conn > C_CONNECTED && os.disk == D_UP_TO_DATE) {
4477                 /* If we are (becoming) SyncSource, but peer is still in sync
4478                  * preparation, ignore its uptodate-ness to avoid flapping, it
4479                  * will change to inconsistent once the peer reaches active
4480                  * syncing states.
4481                  * It may have changed syncer-paused flags, however, so we
4482                  * cannot ignore this completely. */
4483                 if (peer_state.conn > C_CONNECTED &&
4484                     peer_state.conn < C_SYNC_SOURCE)
4485                         real_peer_disk = D_INCONSISTENT;
4486
4487                 /* if peer_state changes to connected at the same time,
4488                  * it explicitly notifies us that it finished resync.
4489                  * Maybe we should finish it up, too? */
4490                 else if (os.conn >= C_SYNC_SOURCE &&
4491                          peer_state.conn == C_CONNECTED) {
4492                         if (drbd_bm_total_weight(device) <= device->rs_failed)
4493                                 drbd_resync_finished(device);
4494                         return 0;
4495                 }
4496         }
4497
4498         /* explicit verify finished notification, stop sector reached. */
4499         if (os.conn == C_VERIFY_T && os.disk == D_UP_TO_DATE &&
4500             peer_state.conn == C_CONNECTED && real_peer_disk == D_UP_TO_DATE) {
4501                 ov_out_of_sync_print(device);
4502                 drbd_resync_finished(device);
4503                 return 0;
4504         }
4505
4506         /* peer says his disk is inconsistent, while we think it is uptodate,
4507          * and this happens while the peer still thinks we have a sync going on,
4508          * but we think we are already done with the sync.
4509          * We ignore this to avoid flapping pdsk.
4510          * This should not happen, if the peer is a recent version of drbd. */
4511         if (os.pdsk == D_UP_TO_DATE && real_peer_disk == D_INCONSISTENT &&
4512             os.conn == C_CONNECTED && peer_state.conn > C_SYNC_SOURCE)
4513                 real_peer_disk = D_UP_TO_DATE;
4514
4515         if (ns.conn == C_WF_REPORT_PARAMS)
4516                 ns.conn = C_CONNECTED;
4517
4518         if (peer_state.conn == C_AHEAD)
4519                 ns.conn = C_BEHIND;
4520
4521         /* TODO:
4522          * if (primary and diskless and peer uuid != effective uuid)
4523          *     abort attach on peer;
4524          *
4525          * If this node does not have good data, was already connected, but
4526          * the peer did a late attach only now, trying to "negotiate" with me,
4527          * AND I am currently Primary, possibly frozen, with some specific
4528          * "effective" uuid, this should never be reached, really, because
4529          * we first send the uuids, then the current state.
4530          *
4531          * In this scenario, we already dropped the connection hard
4532          * when we received the unsuitable uuids (receive_uuids().
4533          *
4534          * Should we want to change this, that is: not drop the connection in
4535          * receive_uuids() already, then we would need to add a branch here
4536          * that aborts the attach of "unsuitable uuids" on the peer in case
4537          * this node is currently Diskless Primary.
4538          */
4539
4540         if (device->p_uuid && peer_state.disk >= D_NEGOTIATING &&
4541             get_ldev_if_state(device, D_NEGOTIATING)) {
4542                 int cr; /* consider resync */
4543
4544                 /* if we established a new connection */
4545                 cr  = (os.conn < C_CONNECTED);
4546                 /* if we had an established connection
4547                  * and one of the nodes newly attaches a disk */
4548                 cr |= (os.conn == C_CONNECTED &&
4549                        (peer_state.disk == D_NEGOTIATING ||
4550                         os.disk == D_NEGOTIATING));
4551                 /* if we have both been inconsistent, and the peer has been
4552                  * forced to be UpToDate with --force */
4553                 cr |= test_bit(CONSIDER_RESYNC, &device->flags);
4554                 /* if we had been plain connected, and the admin requested to
4555                  * start a sync by "invalidate" or "invalidate-remote" */
4556                 cr |= (os.conn == C_CONNECTED &&
4557                                 (peer_state.conn >= C_STARTING_SYNC_S &&
4558                                  peer_state.conn <= C_WF_BITMAP_T));
4559
4560                 if (cr)
4561                         ns.conn = drbd_sync_handshake(peer_device, peer_state.role, real_peer_disk);
4562
4563                 put_ldev(device);
4564                 if (ns.conn == C_MASK) {
4565                         ns.conn = C_CONNECTED;
4566                         if (device->state.disk == D_NEGOTIATING) {
4567                                 drbd_force_state(device, NS(disk, D_FAILED));
4568                         } else if (peer_state.disk == D_NEGOTIATING) {
4569                                 drbd_err(device, "Disk attach process on the peer node was aborted.\n");
4570                                 peer_state.disk = D_DISKLESS;
4571                                 real_peer_disk = D_DISKLESS;
4572                         } else {
4573                                 if (test_and_clear_bit(CONN_DRY_RUN, &peer_device->connection->flags))
4574                                         return -EIO;
4575                                 D_ASSERT(device, os.conn == C_WF_REPORT_PARAMS);
4576                                 conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD);
4577                                 return -EIO;
4578                         }
4579                 }
4580         }
4581
4582         spin_lock_irq(&device->resource->req_lock);
4583         if (os.i != drbd_read_state(device).i)
4584                 goto retry;
4585         clear_bit(CONSIDER_RESYNC, &device->flags);
4586         ns.peer = peer_state.role;
4587         ns.pdsk = real_peer_disk;
4588         ns.peer_isp = (peer_state.aftr_isp | peer_state.user_isp);
4589         if ((ns.conn == C_CONNECTED || ns.conn == C_WF_BITMAP_S) && ns.disk == D_NEGOTIATING)
4590                 ns.disk = device->new_state_tmp.disk;
4591         cs_flags = CS_VERBOSE + (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED ? 0 : CS_HARD);
4592         if (ns.pdsk == D_CONSISTENT && drbd_suspended(device) && ns.conn == C_CONNECTED && os.conn < C_CONNECTED &&
4593             test_bit(NEW_CUR_UUID, &device->flags)) {
4594                 /* Do not allow tl_restart(RESEND) for a rebooted peer. We can only allow this
4595                    for temporal network outages! */
4596                 spin_unlock_irq(&device->resource->req_lock);
4597                 drbd_err(device, "Aborting Connect, can not thaw IO with an only Consistent peer\n");
4598                 tl_clear(peer_device->connection);
4599                 drbd_uuid_new_current(device);
4600                 clear_bit(NEW_CUR_UUID, &device->flags);
4601                 conn_request_state(peer_device->connection, NS2(conn, C_PROTOCOL_ERROR, susp, 0), CS_HARD);
4602                 return -EIO;
4603         }
4604         rv = _drbd_set_state(device, ns, cs_flags, NULL);
4605         ns = drbd_read_state(device);
4606         spin_unlock_irq(&device->resource->req_lock);
4607
4608         if (rv < SS_SUCCESS) {
4609                 conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD);
4610                 return -EIO;
4611         }
4612
4613         if (os.conn > C_WF_REPORT_PARAMS) {
4614                 if (ns.conn > C_CONNECTED && peer_state.conn <= C_CONNECTED &&
4615                     peer_state.disk != D_NEGOTIATING ) {
4616                         /* we want resync, peer has not yet decided to sync... */
4617                         /* Nowadays only used when forcing a node into primary role and
4618                            setting its disk to UpToDate with that */
4619                         drbd_send_uuids(peer_device);
4620                         drbd_send_current_state(peer_device);
4621                 }
4622         }
4623
4624         clear_bit(DISCARD_MY_DATA, &device->flags);
4625
4626         drbd_md_sync(device); /* update connected indicator, la_size_sect, ... */
4627
4628         return 0;
4629 }
4630
4631 static int receive_sync_uuid(struct drbd_connection *connection, struct packet_info *pi)
4632 {
4633         struct drbd_peer_device *peer_device;
4634         struct drbd_device *device;
4635         struct p_rs_uuid *p = pi->data;
4636
4637         peer_device = conn_peer_device(connection, pi->vnr);
4638         if (!peer_device)
4639                 return -EIO;
4640         device = peer_device->device;
4641
4642         wait_event(device->misc_wait,
4643                    device->state.conn == C_WF_SYNC_UUID ||
4644                    device->state.conn == C_BEHIND ||
4645                    device->state.conn < C_CONNECTED ||
4646                    device->state.disk < D_NEGOTIATING);
4647
4648         /* D_ASSERT(device,  device->state.conn == C_WF_SYNC_UUID ); */
4649
4650         /* Here the _drbd_uuid_ functions are right, current should
4651            _not_ be rotated into the history */
4652         if (get_ldev_if_state(device, D_NEGOTIATING)) {
4653                 _drbd_uuid_set(device, UI_CURRENT, be64_to_cpu(p->uuid));
4654                 _drbd_uuid_set(device, UI_BITMAP, 0UL);
4655
4656                 drbd_print_uuids(device, "updated sync uuid");
4657                 drbd_start_resync(device, C_SYNC_TARGET);
4658
4659                 put_ldev(device);
4660         } else
4661                 drbd_err(device, "Ignoring SyncUUID packet!\n");
4662
4663         return 0;
4664 }
4665
4666 /*
4667  * receive_bitmap_plain
4668  *
4669  * Return 0 when done, 1 when another iteration is needed, and a negative error
4670  * code upon failure.
4671  */
4672 static int
4673 receive_bitmap_plain(struct drbd_peer_device *peer_device, unsigned int size,
4674                      unsigned long *p, struct bm_xfer_ctx *c)
4675 {
4676         unsigned int data_size = DRBD_SOCKET_BUFFER_SIZE -
4677                                  drbd_header_size(peer_device->connection);
4678         unsigned int num_words = min_t(size_t, data_size / sizeof(*p),
4679                                        c->bm_words - c->word_offset);
4680         unsigned int want = num_words * sizeof(*p);
4681         int err;
4682
4683         if (want != size) {
4684                 drbd_err(peer_device, "%s:want (%u) != size (%u)\n", __func__, want, size);
4685                 return -EIO;
4686         }
4687         if (want == 0)
4688                 return 0;
4689         err = drbd_recv_all(peer_device->connection, p, want);
4690         if (err)
4691                 return err;
4692
4693         drbd_bm_merge_lel(peer_device->device, c->word_offset, num_words, p);
4694
4695         c->word_offset += num_words;
4696         c->bit_offset = c->word_offset * BITS_PER_LONG;
4697         if (c->bit_offset > c->bm_bits)
4698                 c->bit_offset = c->bm_bits;
4699
4700         return 1;
4701 }
4702
4703 static enum drbd_bitmap_code dcbp_get_code(struct p_compressed_bm *p)
4704 {
4705         return (enum drbd_bitmap_code)(p->encoding & 0x0f);
4706 }
4707
4708 static int dcbp_get_start(struct p_compressed_bm *p)
4709 {
4710         return (p->encoding & 0x80) != 0;
4711 }
4712
4713 static int dcbp_get_pad_bits(struct p_compressed_bm *p)
4714 {
4715         return (p->encoding >> 4) & 0x7;
4716 }
4717
4718 /*
4719  * recv_bm_rle_bits
4720  *
4721  * Return 0 when done, 1 when another iteration is needed, and a negative error
4722  * code upon failure.
4723  */
4724 static int
4725 recv_bm_rle_bits(struct drbd_peer_device *peer_device,
4726                 struct p_compressed_bm *p,
4727                  struct bm_xfer_ctx *c,
4728                  unsigned int len)
4729 {
4730         struct bitstream bs;
4731         u64 look_ahead;
4732         u64 rl;
4733         u64 tmp;
4734         unsigned long s = c->bit_offset;
4735         unsigned long e;
4736         int toggle = dcbp_get_start(p);
4737         int have;
4738         int bits;
4739
4740         bitstream_init(&bs, p->code, len, dcbp_get_pad_bits(p));
4741
4742         bits = bitstream_get_bits(&bs, &look_ahead, 64);
4743         if (bits < 0)
4744                 return -EIO;
4745
4746         for (have = bits; have > 0; s += rl, toggle = !toggle) {
4747                 bits = vli_decode_bits(&rl, look_ahead);
4748                 if (bits <= 0)
4749                         return -EIO;
4750
4751                 if (toggle) {
4752                         e = s + rl -1;
4753                         if (e >= c->bm_bits) {
4754                                 drbd_err(peer_device, "bitmap overflow (e:%lu) while decoding bm RLE packet\n", e);
4755                                 return -EIO;
4756                         }
4757                         _drbd_bm_set_bits(peer_device->device, s, e);
4758                 }
4759
4760                 if (have < bits) {
4761                         drbd_err(peer_device, "bitmap decoding error: h:%d b:%d la:0x%08llx l:%u/%u\n",
4762                                 have, bits, look_ahead,
4763                                 (unsigned int)(bs.cur.b - p->code),
4764                                 (unsigned int)bs.buf_len);
4765                         return -EIO;
4766                 }
4767                 /* if we consumed all 64 bits, assign 0; >> 64 is "undefined"; */
4768                 if (likely(bits < 64))
4769                         look_ahead >>= bits;
4770                 else
4771                         look_ahead = 0;
4772                 have -= bits;
4773
4774                 bits = bitstream_get_bits(&bs, &tmp, 64 - have);
4775                 if (bits < 0)
4776                         return -EIO;
4777                 look_ahead |= tmp << have;
4778                 have += bits;
4779         }
4780
4781         c->bit_offset = s;
4782         bm_xfer_ctx_bit_to_word_offset(c);
4783
4784         return (s != c->bm_bits);
4785 }
4786
4787 /*
4788  * decode_bitmap_c
4789  *
4790  * Return 0 when done, 1 when another iteration is needed, and a negative error
4791  * code upon failure.
4792  */
4793 static int
4794 decode_bitmap_c(struct drbd_peer_device *peer_device,
4795                 struct p_compressed_bm *p,
4796                 struct bm_xfer_ctx *c,
4797                 unsigned int len)
4798 {
4799         if (dcbp_get_code(p) == RLE_VLI_Bits)
4800                 return recv_bm_rle_bits(peer_device, p, c, len - sizeof(*p));
4801
4802         /* other variants had been implemented for evaluation,
4803          * but have been dropped as this one turned out to be "best"
4804          * during all our tests. */
4805
4806         drbd_err(peer_device, "receive_bitmap_c: unknown encoding %u\n", p->encoding);
4807         conn_request_state(peer_device->connection, NS(conn, C_PROTOCOL_ERROR), CS_HARD);
4808         return -EIO;
4809 }
4810
4811 void INFO_bm_xfer_stats(struct drbd_device *device,
4812                 const char *direction, struct bm_xfer_ctx *c)
4813 {
4814         /* what would it take to transfer it "plaintext" */
4815         unsigned int header_size = drbd_header_size(first_peer_device(device)->connection);
4816         unsigned int data_size = DRBD_SOCKET_BUFFER_SIZE - header_size;
4817         unsigned int plain =
4818                 header_size * (DIV_ROUND_UP(c->bm_words, data_size) + 1) +
4819                 c->bm_words * sizeof(unsigned long);
4820         unsigned int total = c->bytes[0] + c->bytes[1];
4821         unsigned int r;
4822
4823         /* total can not be zero. but just in case: */
4824         if (total == 0)
4825                 return;
4826
4827         /* don't report if not compressed */
4828         if (total >= plain)
4829                 return;
4830
4831         /* total < plain. check for overflow, still */
4832         r = (total > UINT_MAX/1000) ? (total / (plain/1000))
4833                                     : (1000 * total / plain);
4834
4835         if (r > 1000)
4836                 r = 1000;
4837
4838         r = 1000 - r;
4839         drbd_info(device, "%s bitmap stats [Bytes(packets)]: plain %u(%u), RLE %u(%u), "
4840              "total %u; compression: %u.%u%%\n",
4841                         direction,
4842                         c->bytes[1], c->packets[1],
4843                         c->bytes[0], c->packets[0],
4844                         total, r/10, r % 10);
4845 }
4846
4847 /* Since we are processing the bitfield from lower addresses to higher,
4848    it does not matter if the process it in 32 bit chunks or 64 bit
4849    chunks as long as it is little endian. (Understand it as byte stream,
4850    beginning with the lowest byte...) If we would use big endian
4851    we would need to process it from the highest address to the lowest,
4852    in order to be agnostic to the 32 vs 64 bits issue.
4853
4854    returns 0 on failure, 1 if we successfully received it. */
4855 static int receive_bitmap(struct drbd_connection *connection, struct packet_info *pi)
4856 {
4857         struct drbd_peer_device *peer_device;
4858         struct drbd_device *device;
4859         struct bm_xfer_ctx c;
4860         int err;
4861
4862         peer_device = conn_peer_device(connection, pi->vnr);
4863         if (!peer_device)
4864                 return -EIO;
4865         device = peer_device->device;
4866
4867         drbd_bm_lock(device, "receive bitmap", BM_LOCKED_SET_ALLOWED);
4868         /* you are supposed to send additional out-of-sync information
4869          * if you actually set bits during this phase */
4870
4871         c = (struct bm_xfer_ctx) {
4872                 .bm_bits = drbd_bm_bits(device),
4873                 .bm_words = drbd_bm_words(device),
4874         };
4875
4876         for(;;) {
4877                 if (pi->cmd == P_BITMAP)
4878                         err = receive_bitmap_plain(peer_device, pi->size, pi->data, &c);
4879                 else if (pi->cmd == P_COMPRESSED_BITMAP) {
4880                         /* MAYBE: sanity check that we speak proto >= 90,
4881                          * and the feature is enabled! */
4882                         struct p_compressed_bm *p = pi->data;
4883
4884                         if (pi->size > DRBD_SOCKET_BUFFER_SIZE - drbd_header_size(connection)) {
4885                                 drbd_err(device, "ReportCBitmap packet too large\n");
4886                                 err = -EIO;
4887                                 goto out;
4888                         }
4889                         if (pi->size <= sizeof(*p)) {
4890                                 drbd_err(device, "ReportCBitmap packet too small (l:%u)\n", pi->size);
4891                                 err = -EIO;
4892                                 goto out;
4893                         }
4894                         err = drbd_recv_all(peer_device->connection, p, pi->size);
4895                         if (err)
4896                                goto out;
4897                         err = decode_bitmap_c(peer_device, p, &c, pi->size);
4898                 } else {
4899                         drbd_warn(device, "receive_bitmap: cmd neither ReportBitMap nor ReportCBitMap (is 0x%x)", pi->cmd);
4900                         err = -EIO;
4901                         goto out;
4902                 }
4903
4904                 c.packets[pi->cmd == P_BITMAP]++;
4905                 c.bytes[pi->cmd == P_BITMAP] += drbd_header_size(connection) + pi->size;
4906
4907                 if (err <= 0) {
4908                         if (err < 0)
4909                                 goto out;
4910                         break;
4911                 }
4912                 err = drbd_recv_header(peer_device->connection, pi);
4913                 if (err)
4914                         goto out;
4915         }
4916
4917         INFO_bm_xfer_stats(device, "receive", &c);
4918
4919         if (device->state.conn == C_WF_BITMAP_T) {
4920                 enum drbd_state_rv rv;
4921
4922                 err = drbd_send_bitmap(device);
4923                 if (err)
4924                         goto out;
4925                 /* Omit CS_ORDERED with this state transition to avoid deadlocks. */
4926                 rv = _drbd_request_state(device, NS(conn, C_WF_SYNC_UUID), CS_VERBOSE);
4927                 D_ASSERT(device, rv == SS_SUCCESS);
4928         } else if (device->state.conn != C_WF_BITMAP_S) {
4929                 /* admin may have requested C_DISCONNECTING,
4930                  * other threads may have noticed network errors */
4931                 drbd_info(device, "unexpected cstate (%s) in receive_bitmap\n",
4932                     drbd_conn_str(device->state.conn));
4933         }
4934         err = 0;
4935
4936  out:
4937         drbd_bm_unlock(device);
4938         if (!err && device->state.conn == C_WF_BITMAP_S)
4939                 drbd_start_resync(device, C_SYNC_SOURCE);
4940         return err;
4941 }
4942
4943 static int receive_skip(struct drbd_connection *connection, struct packet_info *pi)
4944 {
4945         drbd_warn(connection, "skipping unknown optional packet type %d, l: %d!\n",
4946                  pi->cmd, pi->size);
4947
4948         return ignore_remaining_packet(connection, pi);
4949 }
4950
4951 static int receive_UnplugRemote(struct drbd_connection *connection, struct packet_info *pi)
4952 {
4953         /* Make sure we've acked all the TCP data associated
4954          * with the data requests being unplugged */
4955         tcp_sock_set_quickack(connection->data.socket->sk, 2);
4956         return 0;
4957 }
4958
4959 static int receive_out_of_sync(struct drbd_connection *connection, struct packet_info *pi)
4960 {
4961         struct drbd_peer_device *peer_device;
4962         struct drbd_device *device;
4963         struct p_block_desc *p = pi->data;
4964
4965         peer_device = conn_peer_device(connection, pi->vnr);
4966         if (!peer_device)
4967                 return -EIO;
4968         device = peer_device->device;
4969
4970         switch (device->state.conn) {
4971         case C_WF_SYNC_UUID:
4972         case C_WF_BITMAP_T:
4973         case C_BEHIND:
4974                         break;
4975         default:
4976                 drbd_err(device, "ASSERT FAILED cstate = %s, expected: WFSyncUUID|WFBitMapT|Behind\n",
4977                                 drbd_conn_str(device->state.conn));
4978         }
4979
4980         drbd_set_out_of_sync(device, be64_to_cpu(p->sector), be32_to_cpu(p->blksize));
4981
4982         return 0;
4983 }
4984
4985 static int receive_rs_deallocated(struct drbd_connection *connection, struct packet_info *pi)
4986 {
4987         struct drbd_peer_device *peer_device;
4988         struct p_block_desc *p = pi->data;
4989         struct drbd_device *device;
4990         sector_t sector;
4991         int size, err = 0;
4992
4993         peer_device = conn_peer_device(connection, pi->vnr);
4994         if (!peer_device)
4995                 return -EIO;
4996         device = peer_device->device;
4997
4998         sector = be64_to_cpu(p->sector);
4999         size = be32_to_cpu(p->blksize);
5000
5001         dec_rs_pending(device);
5002
5003         if (get_ldev(device)) {
5004                 struct drbd_peer_request *peer_req;
5005                 const int op = REQ_OP_WRITE_ZEROES;
5006
5007                 peer_req = drbd_alloc_peer_req(peer_device, ID_SYNCER, sector,
5008                                                size, 0, GFP_NOIO);
5009                 if (!peer_req) {
5010                         put_ldev(device);
5011                         return -ENOMEM;
5012                 }
5013
5014                 peer_req->w.cb = e_end_resync_block;
5015                 peer_req->submit_jif = jiffies;
5016                 peer_req->flags |= EE_TRIM;
5017
5018                 spin_lock_irq(&device->resource->req_lock);
5019                 list_add_tail(&peer_req->w.list, &device->sync_ee);
5020                 spin_unlock_irq(&device->resource->req_lock);
5021
5022                 atomic_add(pi->size >> 9, &device->rs_sect_ev);
5023                 err = drbd_submit_peer_request(device, peer_req, op, 0, DRBD_FAULT_RS_WR);
5024
5025                 if (err) {
5026                         spin_lock_irq(&device->resource->req_lock);
5027                         list_del(&peer_req->w.list);
5028                         spin_unlock_irq(&device->resource->req_lock);
5029
5030                         drbd_free_peer_req(device, peer_req);
5031                         put_ldev(device);
5032                         err = 0;
5033                         goto fail;
5034                 }
5035
5036                 inc_unacked(device);
5037
5038                 /* No put_ldev() here. Gets called in drbd_endio_write_sec_final(),
5039                    as well as drbd_rs_complete_io() */
5040         } else {
5041         fail:
5042                 drbd_rs_complete_io(device, sector);
5043                 drbd_send_ack_ex(peer_device, P_NEG_ACK, sector, size, ID_SYNCER);
5044         }
5045
5046         atomic_add(size >> 9, &device->rs_sect_in);
5047
5048         return err;
5049 }
5050
5051 struct data_cmd {
5052         int expect_payload;
5053         unsigned int pkt_size;
5054         int (*fn)(struct drbd_connection *, struct packet_info *);
5055 };
5056
5057 static struct data_cmd drbd_cmd_handler[] = {
5058         [P_DATA]            = { 1, sizeof(struct p_data), receive_Data },
5059         [P_DATA_REPLY]      = { 1, sizeof(struct p_data), receive_DataReply },
5060         [P_RS_DATA_REPLY]   = { 1, sizeof(struct p_data), receive_RSDataReply } ,
5061         [P_BARRIER]         = { 0, sizeof(struct p_barrier), receive_Barrier } ,
5062         [P_BITMAP]          = { 1, 0, receive_bitmap } ,
5063         [P_COMPRESSED_BITMAP] = { 1, 0, receive_bitmap } ,
5064         [P_UNPLUG_REMOTE]   = { 0, 0, receive_UnplugRemote },
5065         [P_DATA_REQUEST]    = { 0, sizeof(struct p_block_req), receive_DataRequest },
5066         [P_RS_DATA_REQUEST] = { 0, sizeof(struct p_block_req), receive_DataRequest },
5067         [P_SYNC_PARAM]      = { 1, 0, receive_SyncParam },
5068         [P_SYNC_PARAM89]    = { 1, 0, receive_SyncParam },
5069         [P_PROTOCOL]        = { 1, sizeof(struct p_protocol), receive_protocol },
5070         [P_UUIDS]           = { 0, sizeof(struct p_uuids), receive_uuids },
5071         [P_SIZES]           = { 0, sizeof(struct p_sizes), receive_sizes },
5072         [P_STATE]           = { 0, sizeof(struct p_state), receive_state },
5073         [P_STATE_CHG_REQ]   = { 0, sizeof(struct p_req_state), receive_req_state },
5074         [P_SYNC_UUID]       = { 0, sizeof(struct p_rs_uuid), receive_sync_uuid },
5075         [P_OV_REQUEST]      = { 0, sizeof(struct p_block_req), receive_DataRequest },
5076         [P_OV_REPLY]        = { 1, sizeof(struct p_block_req), receive_DataRequest },
5077         [P_CSUM_RS_REQUEST] = { 1, sizeof(struct p_block_req), receive_DataRequest },
5078         [P_RS_THIN_REQ]     = { 0, sizeof(struct p_block_req), receive_DataRequest },
5079         [P_DELAY_PROBE]     = { 0, sizeof(struct p_delay_probe93), receive_skip },
5080         [P_OUT_OF_SYNC]     = { 0, sizeof(struct p_block_desc), receive_out_of_sync },
5081         [P_CONN_ST_CHG_REQ] = { 0, sizeof(struct p_req_state), receive_req_conn_state },
5082         [P_PROTOCOL_UPDATE] = { 1, sizeof(struct p_protocol), receive_protocol },
5083         [P_TRIM]            = { 0, sizeof(struct p_trim), receive_Data },
5084         [P_ZEROES]          = { 0, sizeof(struct p_trim), receive_Data },
5085         [P_RS_DEALLOCATED]  = { 0, sizeof(struct p_block_desc), receive_rs_deallocated },
5086         [P_WSAME]           = { 1, sizeof(struct p_wsame), receive_Data },
5087 };
5088
5089 static void drbdd(struct drbd_connection *connection)
5090 {
5091         struct packet_info pi;
5092         size_t shs; /* sub header size */
5093         int err;
5094
5095         while (get_t_state(&connection->receiver) == RUNNING) {
5096                 struct data_cmd const *cmd;
5097
5098                 drbd_thread_current_set_cpu(&connection->receiver);
5099                 update_receiver_timing_details(connection, drbd_recv_header_maybe_unplug);
5100                 if (drbd_recv_header_maybe_unplug(connection, &pi))
5101                         goto err_out;
5102
5103                 cmd = &drbd_cmd_handler[pi.cmd];
5104                 if (unlikely(pi.cmd >= ARRAY_SIZE(drbd_cmd_handler) || !cmd->fn)) {
5105                         drbd_err(connection, "Unexpected data packet %s (0x%04x)",
5106                                  cmdname(pi.cmd), pi.cmd);
5107                         goto err_out;
5108                 }
5109
5110                 shs = cmd->pkt_size;
5111                 if (pi.cmd == P_SIZES && connection->agreed_features & DRBD_FF_WSAME)
5112                         shs += sizeof(struct o_qlim);
5113                 if (pi.size > shs && !cmd->expect_payload) {
5114                         drbd_err(connection, "No payload expected %s l:%d\n",
5115                                  cmdname(pi.cmd), pi.size);
5116                         goto err_out;
5117                 }
5118                 if (pi.size < shs) {
5119                         drbd_err(connection, "%s: unexpected packet size, expected:%d received:%d\n",
5120                                  cmdname(pi.cmd), (int)shs, pi.size);
5121                         goto err_out;
5122                 }
5123
5124                 if (shs) {
5125                         update_receiver_timing_details(connection, drbd_recv_all_warn);
5126                         err = drbd_recv_all_warn(connection, pi.data, shs);
5127                         if (err)
5128                                 goto err_out;
5129                         pi.size -= shs;
5130                 }
5131
5132                 update_receiver_timing_details(connection, cmd->fn);
5133                 err = cmd->fn(connection, &pi);
5134                 if (err) {
5135                         drbd_err(connection, "error receiving %s, e: %d l: %d!\n",
5136                                  cmdname(pi.cmd), err, pi.size);
5137                         goto err_out;
5138                 }
5139         }
5140         return;
5141
5142     err_out:
5143         conn_request_state(connection, NS(conn, C_PROTOCOL_ERROR), CS_HARD);
5144 }
5145
5146 static void conn_disconnect(struct drbd_connection *connection)
5147 {
5148         struct drbd_peer_device *peer_device;
5149         enum drbd_conns oc;
5150         int vnr;
5151
5152         if (connection->cstate == C_STANDALONE)
5153                 return;
5154
5155         /* We are about to start the cleanup after connection loss.
5156          * Make sure drbd_make_request knows about that.
5157          * Usually we should be in some network failure state already,
5158          * but just in case we are not, we fix it up here.
5159          */
5160         conn_request_state(connection, NS(conn, C_NETWORK_FAILURE), CS_HARD);
5161
5162         /* ack_receiver does not clean up anything. it must not interfere, either */
5163         drbd_thread_stop(&connection->ack_receiver);
5164         if (connection->ack_sender) {
5165                 destroy_workqueue(connection->ack_sender);
5166                 connection->ack_sender = NULL;
5167         }
5168         drbd_free_sock(connection);
5169
5170         rcu_read_lock();
5171         idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
5172                 struct drbd_device *device = peer_device->device;
5173                 kref_get(&device->kref);
5174                 rcu_read_unlock();
5175                 drbd_disconnected(peer_device);
5176                 kref_put(&device->kref, drbd_destroy_device);
5177                 rcu_read_lock();
5178         }
5179         rcu_read_unlock();
5180
5181         if (!list_empty(&connection->current_epoch->list))
5182                 drbd_err(connection, "ASSERTION FAILED: connection->current_epoch->list not empty\n");
5183         /* ok, no more ee's on the fly, it is safe to reset the epoch_size */
5184         atomic_set(&connection->current_epoch->epoch_size, 0);
5185         connection->send.seen_any_write_yet = false;
5186
5187         drbd_info(connection, "Connection closed\n");
5188
5189         if (conn_highest_role(connection) == R_PRIMARY && conn_highest_pdsk(connection) >= D_UNKNOWN)
5190                 conn_try_outdate_peer_async(connection);
5191
5192         spin_lock_irq(&connection->resource->req_lock);
5193         oc = connection->cstate;
5194         if (oc >= C_UNCONNECTED)
5195                 _conn_request_state(connection, NS(conn, C_UNCONNECTED), CS_VERBOSE);
5196
5197         spin_unlock_irq(&connection->resource->req_lock);
5198
5199         if (oc == C_DISCONNECTING)
5200                 conn_request_state(connection, NS(conn, C_STANDALONE), CS_VERBOSE | CS_HARD);
5201 }
5202
5203 static int drbd_disconnected(struct drbd_peer_device *peer_device)
5204 {
5205         struct drbd_device *device = peer_device->device;
5206         unsigned int i;
5207
5208         /* wait for current activity to cease. */
5209         spin_lock_irq(&device->resource->req_lock);
5210         _drbd_wait_ee_list_empty(device, &device->active_ee);
5211         _drbd_wait_ee_list_empty(device, &device->sync_ee);
5212         _drbd_wait_ee_list_empty(device, &device->read_ee);
5213         spin_unlock_irq(&device->resource->req_lock);
5214
5215         /* We do not have data structures that would allow us to
5216          * get the rs_pending_cnt down to 0 again.
5217          *  * On C_SYNC_TARGET we do not have any data structures describing
5218          *    the pending RSDataRequest's we have sent.
5219          *  * On C_SYNC_SOURCE there is no data structure that tracks
5220          *    the P_RS_DATA_REPLY blocks that we sent to the SyncTarget.
5221          *  And no, it is not the sum of the reference counts in the
5222          *  resync_LRU. The resync_LRU tracks the whole operation including
5223          *  the disk-IO, while the rs_pending_cnt only tracks the blocks
5224          *  on the fly. */
5225         drbd_rs_cancel_all(device);
5226         device->rs_total = 0;
5227         device->rs_failed = 0;
5228         atomic_set(&device->rs_pending_cnt, 0);
5229         wake_up(&device->misc_wait);
5230
5231         del_timer_sync(&device->resync_timer);
5232         resync_timer_fn(&device->resync_timer);
5233
5234         /* wait for all w_e_end_data_req, w_e_end_rsdata_req, w_send_barrier,
5235          * w_make_resync_request etc. which may still be on the worker queue
5236          * to be "canceled" */
5237         drbd_flush_workqueue(&peer_device->connection->sender_work);
5238
5239         drbd_finish_peer_reqs(device);
5240
5241         /* This second workqueue flush is necessary, since drbd_finish_peer_reqs()
5242            might have issued a work again. The one before drbd_finish_peer_reqs() is
5243            necessary to reclain net_ee in drbd_finish_peer_reqs(). */
5244         drbd_flush_workqueue(&peer_device->connection->sender_work);
5245
5246         /* need to do it again, drbd_finish_peer_reqs() may have populated it
5247          * again via drbd_try_clear_on_disk_bm(). */
5248         drbd_rs_cancel_all(device);
5249
5250         kfree(device->p_uuid);
5251         device->p_uuid = NULL;
5252
5253         if (!drbd_suspended(device))
5254                 tl_clear(peer_device->connection);
5255
5256         drbd_md_sync(device);
5257
5258         if (get_ldev(device)) {
5259                 drbd_bitmap_io(device, &drbd_bm_write_copy_pages,
5260                                 "write from disconnected", BM_LOCKED_CHANGE_ALLOWED);
5261                 put_ldev(device);
5262         }
5263
5264         /* tcp_close and release of sendpage pages can be deferred.  I don't
5265          * want to use SO_LINGER, because apparently it can be deferred for
5266          * more than 20 seconds (longest time I checked).
5267          *
5268          * Actually we don't care for exactly when the network stack does its
5269          * put_page(), but release our reference on these pages right here.
5270          */
5271         i = drbd_free_peer_reqs(device, &device->net_ee);
5272         if (i)
5273                 drbd_info(device, "net_ee not empty, killed %u entries\n", i);
5274         i = atomic_read(&device->pp_in_use_by_net);
5275         if (i)
5276                 drbd_info(device, "pp_in_use_by_net = %d, expected 0\n", i);
5277         i = atomic_read(&device->pp_in_use);
5278         if (i)
5279                 drbd_info(device, "pp_in_use = %d, expected 0\n", i);
5280
5281         D_ASSERT(device, list_empty(&device->read_ee));
5282         D_ASSERT(device, list_empty(&device->active_ee));
5283         D_ASSERT(device, list_empty(&device->sync_ee));
5284         D_ASSERT(device, list_empty(&device->done_ee));
5285
5286         return 0;
5287 }
5288
5289 /*
5290  * We support PRO_VERSION_MIN to PRO_VERSION_MAX. The protocol version
5291  * we can agree on is stored in agreed_pro_version.
5292  *
5293  * feature flags and the reserved array should be enough room for future
5294  * enhancements of the handshake protocol, and possible plugins...
5295  *
5296  * for now, they are expected to be zero, but ignored.
5297  */
5298 static int drbd_send_features(struct drbd_connection *connection)
5299 {
5300         struct drbd_socket *sock;
5301         struct p_connection_features *p;
5302
5303         sock = &connection->data;
5304         p = conn_prepare_command(connection, sock);
5305         if (!p)
5306                 return -EIO;
5307         memset(p, 0, sizeof(*p));
5308         p->protocol_min = cpu_to_be32(PRO_VERSION_MIN);
5309         p->protocol_max = cpu_to_be32(PRO_VERSION_MAX);
5310         p->feature_flags = cpu_to_be32(PRO_FEATURES);
5311         return conn_send_command(connection, sock, P_CONNECTION_FEATURES, sizeof(*p), NULL, 0);
5312 }
5313
5314 /*
5315  * return values:
5316  *   1 yes, we have a valid connection
5317  *   0 oops, did not work out, please try again
5318  *  -1 peer talks different language,
5319  *     no point in trying again, please go standalone.
5320  */
5321 static int drbd_do_features(struct drbd_connection *connection)
5322 {
5323         /* ASSERT current == connection->receiver ... */
5324         struct p_connection_features *p;
5325         const int expect = sizeof(struct p_connection_features);
5326         struct packet_info pi;
5327         int err;
5328
5329         err = drbd_send_features(connection);
5330         if (err)
5331                 return 0;
5332
5333         err = drbd_recv_header(connection, &pi);
5334         if (err)
5335                 return 0;
5336
5337         if (pi.cmd != P_CONNECTION_FEATURES) {
5338                 drbd_err(connection, "expected ConnectionFeatures packet, received: %s (0x%04x)\n",
5339                          cmdname(pi.cmd), pi.cmd);
5340                 return -1;
5341         }
5342
5343         if (pi.size != expect) {
5344                 drbd_err(connection, "expected ConnectionFeatures length: %u, received: %u\n",
5345                      expect, pi.size);
5346                 return -1;
5347         }
5348
5349         p = pi.data;
5350         err = drbd_recv_all_warn(connection, p, expect);
5351         if (err)
5352                 return 0;
5353
5354         p->protocol_min = be32_to_cpu(p->protocol_min);
5355         p->protocol_max = be32_to_cpu(p->protocol_max);
5356         if (p->protocol_max == 0)
5357                 p->protocol_max = p->protocol_min;
5358
5359         if (PRO_VERSION_MAX < p->protocol_min ||
5360             PRO_VERSION_MIN > p->protocol_max)
5361                 goto incompat;
5362
5363         connection->agreed_pro_version = min_t(int, PRO_VERSION_MAX, p->protocol_max);
5364         connection->agreed_features = PRO_FEATURES & be32_to_cpu(p->feature_flags);
5365
5366         drbd_info(connection, "Handshake successful: "
5367              "Agreed network protocol version %d\n", connection->agreed_pro_version);
5368
5369         drbd_info(connection, "Feature flags enabled on protocol level: 0x%x%s%s%s%s.\n",
5370                   connection->agreed_features,
5371                   connection->agreed_features & DRBD_FF_TRIM ? " TRIM" : "",
5372                   connection->agreed_features & DRBD_FF_THIN_RESYNC ? " THIN_RESYNC" : "",
5373                   connection->agreed_features & DRBD_FF_WSAME ? " WRITE_SAME" : "",
5374                   connection->agreed_features & DRBD_FF_WZEROES ? " WRITE_ZEROES" :
5375                   connection->agreed_features ? "" : " none");
5376
5377         return 1;
5378
5379  incompat:
5380         drbd_err(connection, "incompatible DRBD dialects: "
5381             "I support %d-%d, peer supports %d-%d\n",
5382             PRO_VERSION_MIN, PRO_VERSION_MAX,
5383             p->protocol_min, p->protocol_max);
5384         return -1;
5385 }
5386
5387 #if !defined(CONFIG_CRYPTO_HMAC) && !defined(CONFIG_CRYPTO_HMAC_MODULE)
5388 static int drbd_do_auth(struct drbd_connection *connection)
5389 {
5390         drbd_err(connection, "This kernel was build without CONFIG_CRYPTO_HMAC.\n");
5391         drbd_err(connection, "You need to disable 'cram-hmac-alg' in drbd.conf.\n");
5392         return -1;
5393 }
5394 #else
5395 #define CHALLENGE_LEN 64
5396
5397 /* Return value:
5398         1 - auth succeeded,
5399         0 - failed, try again (network error),
5400         -1 - auth failed, don't try again.
5401 */
5402
5403 static int drbd_do_auth(struct drbd_connection *connection)
5404 {
5405         struct drbd_socket *sock;
5406         char my_challenge[CHALLENGE_LEN];  /* 64 Bytes... */
5407         char *response = NULL;
5408         char *right_response = NULL;
5409         char *peers_ch = NULL;
5410         unsigned int key_len;
5411         char secret[SHARED_SECRET_MAX]; /* 64 byte */
5412         unsigned int resp_size;
5413         struct shash_desc *desc;
5414         struct packet_info pi;
5415         struct net_conf *nc;
5416         int err, rv;
5417
5418         /* FIXME: Put the challenge/response into the preallocated socket buffer.  */
5419
5420         rcu_read_lock();
5421         nc = rcu_dereference(connection->net_conf);
5422         key_len = strlen(nc->shared_secret);
5423         memcpy(secret, nc->shared_secret, key_len);
5424         rcu_read_unlock();
5425
5426         desc = kmalloc(sizeof(struct shash_desc) +
5427                        crypto_shash_descsize(connection->cram_hmac_tfm),
5428                        GFP_KERNEL);
5429         if (!desc) {
5430                 rv = -1;
5431                 goto fail;
5432         }
5433         desc->tfm = connection->cram_hmac_tfm;
5434
5435         rv = crypto_shash_setkey(connection->cram_hmac_tfm, (u8 *)secret, key_len);
5436         if (rv) {
5437                 drbd_err(connection, "crypto_shash_setkey() failed with %d\n", rv);
5438                 rv = -1;
5439                 goto fail;
5440         }
5441
5442         get_random_bytes(my_challenge, CHALLENGE_LEN);
5443
5444         sock = &connection->data;
5445         if (!conn_prepare_command(connection, sock)) {
5446                 rv = 0;
5447                 goto fail;
5448         }
5449         rv = !conn_send_command(connection, sock, P_AUTH_CHALLENGE, 0,
5450                                 my_challenge, CHALLENGE_LEN);
5451         if (!rv)
5452                 goto fail;
5453
5454         err = drbd_recv_header(connection, &pi);
5455         if (err) {
5456                 rv = 0;
5457                 goto fail;
5458         }
5459
5460         if (pi.cmd != P_AUTH_CHALLENGE) {
5461                 drbd_err(connection, "expected AuthChallenge packet, received: %s (0x%04x)\n",
5462                          cmdname(pi.cmd), pi.cmd);
5463                 rv = -1;
5464                 goto fail;
5465         }
5466
5467         if (pi.size > CHALLENGE_LEN * 2) {
5468                 drbd_err(connection, "expected AuthChallenge payload too big.\n");
5469                 rv = -1;
5470                 goto fail;
5471         }
5472
5473         if (pi.size < CHALLENGE_LEN) {
5474                 drbd_err(connection, "AuthChallenge payload too small.\n");
5475                 rv = -1;
5476                 goto fail;
5477         }
5478
5479         peers_ch = kmalloc(pi.size, GFP_NOIO);
5480         if (!peers_ch) {
5481                 rv = -1;
5482                 goto fail;
5483         }
5484
5485         err = drbd_recv_all_warn(connection, peers_ch, pi.size);
5486         if (err) {
5487                 rv = 0;
5488                 goto fail;
5489         }
5490
5491         if (!memcmp(my_challenge, peers_ch, CHALLENGE_LEN)) {
5492                 drbd_err(connection, "Peer presented the same challenge!\n");
5493                 rv = -1;
5494                 goto fail;
5495         }
5496
5497         resp_size = crypto_shash_digestsize(connection->cram_hmac_tfm);
5498         response = kmalloc(resp_size, GFP_NOIO);
5499         if (!response) {
5500                 rv = -1;
5501                 goto fail;
5502         }
5503
5504         rv = crypto_shash_digest(desc, peers_ch, pi.size, response);
5505         if (rv) {
5506                 drbd_err(connection, "crypto_hash_digest() failed with %d\n", rv);
5507                 rv = -1;
5508                 goto fail;
5509         }
5510
5511         if (!conn_prepare_command(connection, sock)) {
5512                 rv = 0;
5513                 goto fail;
5514         }
5515         rv = !conn_send_command(connection, sock, P_AUTH_RESPONSE, 0,
5516                                 response, resp_size);
5517         if (!rv)
5518                 goto fail;
5519
5520         err = drbd_recv_header(connection, &pi);
5521         if (err) {
5522                 rv = 0;
5523                 goto fail;
5524         }
5525
5526         if (pi.cmd != P_AUTH_RESPONSE) {
5527                 drbd_err(connection, "expected AuthResponse packet, received: %s (0x%04x)\n",
5528                          cmdname(pi.cmd), pi.cmd);
5529                 rv = 0;
5530                 goto fail;
5531         }
5532
5533         if (pi.size != resp_size) {
5534                 drbd_err(connection, "expected AuthResponse payload of wrong size\n");
5535                 rv = 0;
5536                 goto fail;
5537         }
5538
5539         err = drbd_recv_all_warn(connection, response , resp_size);
5540         if (err) {
5541                 rv = 0;
5542                 goto fail;
5543         }
5544
5545         right_response = kmalloc(resp_size, GFP_NOIO);
5546         if (!right_response) {
5547                 rv = -1;
5548                 goto fail;
5549         }
5550
5551         rv = crypto_shash_digest(desc, my_challenge, CHALLENGE_LEN,
5552                                  right_response);
5553         if (rv) {
5554                 drbd_err(connection, "crypto_hash_digest() failed with %d\n", rv);
5555                 rv = -1;
5556                 goto fail;
5557         }
5558
5559         rv = !memcmp(response, right_response, resp_size);
5560
5561         if (rv)
5562                 drbd_info(connection, "Peer authenticated using %d bytes HMAC\n",
5563                      resp_size);
5564         else
5565                 rv = -1;
5566
5567  fail:
5568         kfree(peers_ch);
5569         kfree(response);
5570         kfree(right_response);
5571         if (desc) {
5572                 shash_desc_zero(desc);
5573                 kfree(desc);
5574         }
5575
5576         return rv;
5577 }
5578 #endif
5579
5580 int drbd_receiver(struct drbd_thread *thi)
5581 {
5582         struct drbd_connection *connection = thi->connection;
5583         int h;
5584
5585         drbd_info(connection, "receiver (re)started\n");
5586
5587         do {
5588                 h = conn_connect(connection);
5589                 if (h == 0) {
5590                         conn_disconnect(connection);
5591                         schedule_timeout_interruptible(HZ);
5592                 }
5593                 if (h == -1) {
5594                         drbd_warn(connection, "Discarding network configuration.\n");
5595                         conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_HARD);
5596                 }
5597         } while (h == 0);
5598
5599         if (h > 0) {
5600                 blk_start_plug(&connection->receiver_plug);
5601                 drbdd(connection);
5602                 blk_finish_plug(&connection->receiver_plug);
5603         }
5604
5605         conn_disconnect(connection);
5606
5607         drbd_info(connection, "receiver terminated\n");
5608         return 0;
5609 }
5610
5611 /* ********* acknowledge sender ******** */
5612
5613 static int got_conn_RqSReply(struct drbd_connection *connection, struct packet_info *pi)
5614 {
5615         struct p_req_state_reply *p = pi->data;
5616         int retcode = be32_to_cpu(p->retcode);
5617
5618         if (retcode >= SS_SUCCESS) {
5619                 set_bit(CONN_WD_ST_CHG_OKAY, &connection->flags);
5620         } else {
5621                 set_bit(CONN_WD_ST_CHG_FAIL, &connection->flags);
5622                 drbd_err(connection, "Requested state change failed by peer: %s (%d)\n",
5623                          drbd_set_st_err_str(retcode), retcode);
5624         }
5625         wake_up(&connection->ping_wait);
5626
5627         return 0;
5628 }
5629
5630 static int got_RqSReply(struct drbd_connection *connection, struct packet_info *pi)
5631 {
5632         struct drbd_peer_device *peer_device;
5633         struct drbd_device *device;
5634         struct p_req_state_reply *p = pi->data;
5635         int retcode = be32_to_cpu(p->retcode);
5636
5637         peer_device = conn_peer_device(connection, pi->vnr);
5638         if (!peer_device)
5639                 return -EIO;
5640         device = peer_device->device;
5641
5642         if (test_bit(CONN_WD_ST_CHG_REQ, &connection->flags)) {
5643                 D_ASSERT(device, connection->agreed_pro_version < 100);
5644                 return got_conn_RqSReply(connection, pi);
5645         }
5646
5647         if (retcode >= SS_SUCCESS) {
5648                 set_bit(CL_ST_CHG_SUCCESS, &device->flags);
5649         } else {
5650                 set_bit(CL_ST_CHG_FAIL, &device->flags);
5651                 drbd_err(device, "Requested state change failed by peer: %s (%d)\n",
5652                         drbd_set_st_err_str(retcode), retcode);
5653         }
5654         wake_up(&device->state_wait);
5655
5656         return 0;
5657 }
5658
5659 static int got_Ping(struct drbd_connection *connection, struct packet_info *pi)
5660 {
5661         return drbd_send_ping_ack(connection);
5662
5663 }
5664
5665 static int got_PingAck(struct drbd_connection *connection, struct packet_info *pi)
5666 {
5667         /* restore idle timeout */
5668         connection->meta.socket->sk->sk_rcvtimeo = connection->net_conf->ping_int*HZ;
5669         if (!test_and_set_bit(GOT_PING_ACK, &connection->flags))
5670                 wake_up(&connection->ping_wait);
5671
5672         return 0;
5673 }
5674
5675 static int got_IsInSync(struct drbd_connection *connection, struct packet_info *pi)
5676 {
5677         struct drbd_peer_device *peer_device;
5678         struct drbd_device *device;
5679         struct p_block_ack *p = pi->data;
5680         sector_t sector = be64_to_cpu(p->sector);
5681         int blksize = be32_to_cpu(p->blksize);
5682
5683         peer_device = conn_peer_device(connection, pi->vnr);
5684         if (!peer_device)
5685                 return -EIO;
5686         device = peer_device->device;
5687
5688         D_ASSERT(device, peer_device->connection->agreed_pro_version >= 89);
5689
5690         update_peer_seq(peer_device, be32_to_cpu(p->seq_num));
5691
5692         if (get_ldev(device)) {
5693                 drbd_rs_complete_io(device, sector);
5694                 drbd_set_in_sync(device, sector, blksize);
5695                 /* rs_same_csums is supposed to count in units of BM_BLOCK_SIZE */
5696                 device->rs_same_csum += (blksize >> BM_BLOCK_SHIFT);
5697                 put_ldev(device);
5698         }
5699         dec_rs_pending(device);
5700         atomic_add(blksize >> 9, &device->rs_sect_in);
5701
5702         return 0;
5703 }
5704
5705 static int
5706 validate_req_change_req_state(struct drbd_device *device, u64 id, sector_t sector,
5707                               struct rb_root *root, const char *func,
5708                               enum drbd_req_event what, bool missing_ok)
5709 {
5710         struct drbd_request *req;
5711         struct bio_and_error m;
5712
5713         spin_lock_irq(&device->resource->req_lock);
5714         req = find_request(device, root, id, sector, missing_ok, func);
5715         if (unlikely(!req)) {
5716                 spin_unlock_irq(&device->resource->req_lock);
5717                 return -EIO;
5718         }
5719         __req_mod(req, what, &m);
5720         spin_unlock_irq(&device->resource->req_lock);
5721
5722         if (m.bio)
5723                 complete_master_bio(device, &m);
5724         return 0;
5725 }
5726
5727 static int got_BlockAck(struct drbd_connection *connection, struct packet_info *pi)
5728 {
5729         struct drbd_peer_device *peer_device;
5730         struct drbd_device *device;
5731         struct p_block_ack *p = pi->data;
5732         sector_t sector = be64_to_cpu(p->sector);
5733         int blksize = be32_to_cpu(p->blksize);
5734         enum drbd_req_event what;
5735
5736         peer_device = conn_peer_device(connection, pi->vnr);
5737         if (!peer_device)
5738                 return -EIO;
5739         device = peer_device->device;
5740
5741         update_peer_seq(peer_device, be32_to_cpu(p->seq_num));
5742
5743         if (p->block_id == ID_SYNCER) {
5744                 drbd_set_in_sync(device, sector, blksize);
5745                 dec_rs_pending(device);
5746                 return 0;
5747         }
5748         switch (pi->cmd) {
5749         case P_RS_WRITE_ACK:
5750                 what = WRITE_ACKED_BY_PEER_AND_SIS;
5751                 break;
5752         case P_WRITE_ACK:
5753                 what = WRITE_ACKED_BY_PEER;
5754                 break;
5755         case P_RECV_ACK:
5756                 what = RECV_ACKED_BY_PEER;
5757                 break;
5758         case P_SUPERSEDED:
5759                 what = CONFLICT_RESOLVED;
5760                 break;
5761         case P_RETRY_WRITE:
5762                 what = POSTPONE_WRITE;
5763                 break;
5764         default:
5765                 BUG();
5766         }
5767
5768         return validate_req_change_req_state(device, p->block_id, sector,
5769                                              &device->write_requests, __func__,
5770                                              what, false);
5771 }
5772
5773 static int got_NegAck(struct drbd_connection *connection, struct packet_info *pi)
5774 {
5775         struct drbd_peer_device *peer_device;
5776         struct drbd_device *device;
5777         struct p_block_ack *p = pi->data;
5778         sector_t sector = be64_to_cpu(p->sector);
5779         int size = be32_to_cpu(p->blksize);
5780         int err;
5781
5782         peer_device = conn_peer_device(connection, pi->vnr);
5783         if (!peer_device)
5784                 return -EIO;
5785         device = peer_device->device;
5786
5787         update_peer_seq(peer_device, be32_to_cpu(p->seq_num));
5788
5789         if (p->block_id == ID_SYNCER) {
5790                 dec_rs_pending(device);
5791                 drbd_rs_failed_io(device, sector, size);
5792                 return 0;
5793         }
5794
5795         err = validate_req_change_req_state(device, p->block_id, sector,
5796                                             &device->write_requests, __func__,
5797                                             NEG_ACKED, true);
5798         if (err) {
5799                 /* Protocol A has no P_WRITE_ACKs, but has P_NEG_ACKs.
5800                    The master bio might already be completed, therefore the
5801                    request is no longer in the collision hash. */
5802                 /* In Protocol B we might already have got a P_RECV_ACK
5803                    but then get a P_NEG_ACK afterwards. */
5804                 drbd_set_out_of_sync(device, sector, size);
5805         }
5806         return 0;
5807 }
5808
5809 static int got_NegDReply(struct drbd_connection *connection, struct packet_info *pi)
5810 {
5811         struct drbd_peer_device *peer_device;
5812         struct drbd_device *device;
5813         struct p_block_ack *p = pi->data;
5814         sector_t sector = be64_to_cpu(p->sector);
5815
5816         peer_device = conn_peer_device(connection, pi->vnr);
5817         if (!peer_device)
5818                 return -EIO;
5819         device = peer_device->device;
5820
5821         update_peer_seq(peer_device, be32_to_cpu(p->seq_num));
5822
5823         drbd_err(device, "Got NegDReply; Sector %llus, len %u.\n",
5824             (unsigned long long)sector, be32_to_cpu(p->blksize));
5825
5826         return validate_req_change_req_state(device, p->block_id, sector,
5827                                              &device->read_requests, __func__,
5828                                              NEG_ACKED, false);
5829 }
5830
5831 static int got_NegRSDReply(struct drbd_connection *connection, struct packet_info *pi)
5832 {
5833         struct drbd_peer_device *peer_device;
5834         struct drbd_device *device;
5835         sector_t sector;
5836         int size;
5837         struct p_block_ack *p = pi->data;
5838
5839         peer_device = conn_peer_device(connection, pi->vnr);
5840         if (!peer_device)
5841                 return -EIO;
5842         device = peer_device->device;
5843
5844         sector = be64_to_cpu(p->sector);
5845         size = be32_to_cpu(p->blksize);
5846
5847         update_peer_seq(peer_device, be32_to_cpu(p->seq_num));
5848
5849         dec_rs_pending(device);
5850
5851         if (get_ldev_if_state(device, D_FAILED)) {
5852                 drbd_rs_complete_io(device, sector);
5853                 switch (pi->cmd) {
5854                 case P_NEG_RS_DREPLY:
5855                         drbd_rs_failed_io(device, sector, size);
5856                         break;
5857                 case P_RS_CANCEL:
5858                         break;
5859                 default:
5860                         BUG();
5861                 }
5862                 put_ldev(device);
5863         }
5864
5865         return 0;
5866 }
5867
5868 static int got_BarrierAck(struct drbd_connection *connection, struct packet_info *pi)
5869 {
5870         struct p_barrier_ack *p = pi->data;
5871         struct drbd_peer_device *peer_device;
5872         int vnr;
5873
5874         tl_release(connection, p->barrier, be32_to_cpu(p->set_size));
5875
5876         rcu_read_lock();
5877         idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
5878                 struct drbd_device *device = peer_device->device;
5879
5880                 if (device->state.conn == C_AHEAD &&
5881                     atomic_read(&device->ap_in_flight) == 0 &&
5882                     !test_and_set_bit(AHEAD_TO_SYNC_SOURCE, &device->flags)) {
5883                         device->start_resync_timer.expires = jiffies + HZ;
5884                         add_timer(&device->start_resync_timer);
5885                 }
5886         }
5887         rcu_read_unlock();
5888
5889         return 0;
5890 }
5891
5892 static int got_OVResult(struct drbd_connection *connection, struct packet_info *pi)
5893 {
5894         struct drbd_peer_device *peer_device;
5895         struct drbd_device *device;
5896         struct p_block_ack *p = pi->data;
5897         struct drbd_device_work *dw;
5898         sector_t sector;
5899         int size;
5900
5901         peer_device = conn_peer_device(connection, pi->vnr);
5902         if (!peer_device)
5903                 return -EIO;
5904         device = peer_device->device;
5905
5906         sector = be64_to_cpu(p->sector);
5907         size = be32_to_cpu(p->blksize);
5908
5909         update_peer_seq(peer_device, be32_to_cpu(p->seq_num));
5910
5911         if (be64_to_cpu(p->block_id) == ID_OUT_OF_SYNC)
5912                 drbd_ov_out_of_sync_found(device, sector, size);
5913         else
5914                 ov_out_of_sync_print(device);
5915
5916         if (!get_ldev(device))
5917                 return 0;
5918
5919         drbd_rs_complete_io(device, sector);
5920         dec_rs_pending(device);
5921
5922         --device->ov_left;
5923
5924         /* let's advance progress step marks only for every other megabyte */
5925         if ((device->ov_left & 0x200) == 0x200)
5926                 drbd_advance_rs_marks(device, device->ov_left);
5927
5928         if (device->ov_left == 0) {
5929                 dw = kmalloc(sizeof(*dw), GFP_NOIO);
5930                 if (dw) {
5931                         dw->w.cb = w_ov_finished;
5932                         dw->device = device;
5933                         drbd_queue_work(&peer_device->connection->sender_work, &dw->w);
5934                 } else {
5935                         drbd_err(device, "kmalloc(dw) failed.");
5936                         ov_out_of_sync_print(device);
5937                         drbd_resync_finished(device);
5938                 }
5939         }
5940         put_ldev(device);
5941         return 0;
5942 }
5943
5944 static int got_skip(struct drbd_connection *connection, struct packet_info *pi)
5945 {
5946         return 0;
5947 }
5948
5949 struct meta_sock_cmd {
5950         size_t pkt_size;
5951         int (*fn)(struct drbd_connection *connection, struct packet_info *);
5952 };
5953
5954 static void set_rcvtimeo(struct drbd_connection *connection, bool ping_timeout)
5955 {
5956         long t;
5957         struct net_conf *nc;
5958
5959         rcu_read_lock();
5960         nc = rcu_dereference(connection->net_conf);
5961         t = ping_timeout ? nc->ping_timeo : nc->ping_int;
5962         rcu_read_unlock();
5963
5964         t *= HZ;
5965         if (ping_timeout)
5966                 t /= 10;
5967
5968         connection->meta.socket->sk->sk_rcvtimeo = t;
5969 }
5970
5971 static void set_ping_timeout(struct drbd_connection *connection)
5972 {
5973         set_rcvtimeo(connection, 1);
5974 }
5975
5976 static void set_idle_timeout(struct drbd_connection *connection)
5977 {
5978         set_rcvtimeo(connection, 0);
5979 }
5980
5981 static struct meta_sock_cmd ack_receiver_tbl[] = {
5982         [P_PING]            = { 0, got_Ping },
5983         [P_PING_ACK]        = { 0, got_PingAck },
5984         [P_RECV_ACK]        = { sizeof(struct p_block_ack), got_BlockAck },
5985         [P_WRITE_ACK]       = { sizeof(struct p_block_ack), got_BlockAck },
5986         [P_RS_WRITE_ACK]    = { sizeof(struct p_block_ack), got_BlockAck },
5987         [P_SUPERSEDED]   = { sizeof(struct p_block_ack), got_BlockAck },
5988         [P_NEG_ACK]         = { sizeof(struct p_block_ack), got_NegAck },
5989         [P_NEG_DREPLY]      = { sizeof(struct p_block_ack), got_NegDReply },
5990         [P_NEG_RS_DREPLY]   = { sizeof(struct p_block_ack), got_NegRSDReply },
5991         [P_OV_RESULT]       = { sizeof(struct p_block_ack), got_OVResult },
5992         [P_BARRIER_ACK]     = { sizeof(struct p_barrier_ack), got_BarrierAck },
5993         [P_STATE_CHG_REPLY] = { sizeof(struct p_req_state_reply), got_RqSReply },
5994         [P_RS_IS_IN_SYNC]   = { sizeof(struct p_block_ack), got_IsInSync },
5995         [P_DELAY_PROBE]     = { sizeof(struct p_delay_probe93), got_skip },
5996         [P_RS_CANCEL]       = { sizeof(struct p_block_ack), got_NegRSDReply },
5997         [P_CONN_ST_CHG_REPLY]={ sizeof(struct p_req_state_reply), got_conn_RqSReply },
5998         [P_RETRY_WRITE]     = { sizeof(struct p_block_ack), got_BlockAck },
5999 };
6000
6001 int drbd_ack_receiver(struct drbd_thread *thi)
6002 {
6003         struct drbd_connection *connection = thi->connection;
6004         struct meta_sock_cmd *cmd = NULL;
6005         struct packet_info pi;
6006         unsigned long pre_recv_jif;
6007         int rv;
6008         void *buf    = connection->meta.rbuf;
6009         int received = 0;
6010         unsigned int header_size = drbd_header_size(connection);
6011         int expect   = header_size;
6012         bool ping_timeout_active = false;
6013
6014         sched_set_fifo_low(current);
6015
6016         while (get_t_state(thi) == RUNNING) {
6017                 drbd_thread_current_set_cpu(thi);
6018
6019                 conn_reclaim_net_peer_reqs(connection);
6020
6021                 if (test_and_clear_bit(SEND_PING, &connection->flags)) {
6022                         if (drbd_send_ping(connection)) {
6023                                 drbd_err(connection, "drbd_send_ping has failed\n");
6024                                 goto reconnect;
6025                         }
6026                         set_ping_timeout(connection);
6027                         ping_timeout_active = true;
6028                 }
6029
6030                 pre_recv_jif = jiffies;
6031                 rv = drbd_recv_short(connection->meta.socket, buf, expect-received, 0);
6032
6033                 /* Note:
6034                  * -EINTR        (on meta) we got a signal
6035                  * -EAGAIN       (on meta) rcvtimeo expired
6036                  * -ECONNRESET   other side closed the connection
6037                  * -ERESTARTSYS  (on data) we got a signal
6038                  * rv <  0       other than above: unexpected error!
6039                  * rv == expected: full header or command
6040                  * rv <  expected: "woken" by signal during receive
6041                  * rv == 0       : "connection shut down by peer"
6042                  */
6043                 if (likely(rv > 0)) {
6044                         received += rv;
6045                         buf      += rv;
6046                 } else if (rv == 0) {
6047                         if (test_bit(DISCONNECT_SENT, &connection->flags)) {
6048                                 long t;
6049                                 rcu_read_lock();
6050                                 t = rcu_dereference(connection->net_conf)->ping_timeo * HZ/10;
6051                                 rcu_read_unlock();
6052
6053                                 t = wait_event_timeout(connection->ping_wait,
6054                                                        connection->cstate < C_WF_REPORT_PARAMS,
6055                                                        t);
6056                                 if (t)
6057                                         break;
6058                         }
6059                         drbd_err(connection, "meta connection shut down by peer.\n");
6060                         goto reconnect;
6061                 } else if (rv == -EAGAIN) {
6062                         /* If the data socket received something meanwhile,
6063                          * that is good enough: peer is still alive. */
6064                         if (time_after(connection->last_received, pre_recv_jif))
6065                                 continue;
6066                         if (ping_timeout_active) {
6067                                 drbd_err(connection, "PingAck did not arrive in time.\n");
6068                                 goto reconnect;
6069                         }
6070                         set_bit(SEND_PING, &connection->flags);
6071                         continue;
6072                 } else if (rv == -EINTR) {
6073                         /* maybe drbd_thread_stop(): the while condition will notice.
6074                          * maybe woken for send_ping: we'll send a ping above,
6075                          * and change the rcvtimeo */
6076                         flush_signals(current);
6077                         continue;
6078                 } else {
6079                         drbd_err(connection, "sock_recvmsg returned %d\n", rv);
6080                         goto reconnect;
6081                 }
6082
6083                 if (received == expect && cmd == NULL) {
6084                         if (decode_header(connection, connection->meta.rbuf, &pi))
6085                                 goto reconnect;
6086                         cmd = &ack_receiver_tbl[pi.cmd];
6087                         if (pi.cmd >= ARRAY_SIZE(ack_receiver_tbl) || !cmd->fn) {
6088                                 drbd_err(connection, "Unexpected meta packet %s (0x%04x)\n",
6089                                          cmdname(pi.cmd), pi.cmd);
6090                                 goto disconnect;
6091                         }
6092                         expect = header_size + cmd->pkt_size;
6093                         if (pi.size != expect - header_size) {
6094                                 drbd_err(connection, "Wrong packet size on meta (c: %d, l: %d)\n",
6095                                         pi.cmd, pi.size);
6096                                 goto reconnect;
6097                         }
6098                 }
6099                 if (received == expect) {
6100                         bool err;
6101
6102                         err = cmd->fn(connection, &pi);
6103                         if (err) {
6104                                 drbd_err(connection, "%ps failed\n", cmd->fn);
6105                                 goto reconnect;
6106                         }
6107
6108                         connection->last_received = jiffies;
6109
6110                         if (cmd == &ack_receiver_tbl[P_PING_ACK]) {
6111                                 set_idle_timeout(connection);
6112                                 ping_timeout_active = false;
6113                         }
6114
6115                         buf      = connection->meta.rbuf;
6116                         received = 0;
6117                         expect   = header_size;
6118                         cmd      = NULL;
6119                 }
6120         }
6121
6122         if (0) {
6123 reconnect:
6124                 conn_request_state(connection, NS(conn, C_NETWORK_FAILURE), CS_HARD);
6125                 conn_md_sync(connection);
6126         }
6127         if (0) {
6128 disconnect:
6129                 conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_HARD);
6130         }
6131
6132         drbd_info(connection, "ack_receiver terminated\n");
6133
6134         return 0;
6135 }
6136
6137 void drbd_send_acks_wf(struct work_struct *ws)
6138 {
6139         struct drbd_peer_device *peer_device =
6140                 container_of(ws, struct drbd_peer_device, send_acks_work);
6141         struct drbd_connection *connection = peer_device->connection;
6142         struct drbd_device *device = peer_device->device;
6143         struct net_conf *nc;
6144         int tcp_cork, err;
6145
6146         rcu_read_lock();
6147         nc = rcu_dereference(connection->net_conf);
6148         tcp_cork = nc->tcp_cork;
6149         rcu_read_unlock();
6150
6151         if (tcp_cork)
6152                 tcp_sock_set_cork(connection->meta.socket->sk, true);
6153
6154         err = drbd_finish_peer_reqs(device);
6155         kref_put(&device->kref, drbd_destroy_device);
6156         /* get is in drbd_endio_write_sec_final(). That is necessary to keep the
6157            struct work_struct send_acks_work alive, which is in the peer_device object */
6158
6159         if (err) {
6160                 conn_request_state(connection, NS(conn, C_NETWORK_FAILURE), CS_HARD);
6161                 return;
6162         }
6163
6164         if (tcp_cork)
6165                 tcp_sock_set_cork(connection->meta.socket->sk, false);
6166
6167         return;
6168 }