1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 drbd_req.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/slab.h> 17 #include <linux/drbd.h> 18 #include "drbd_int.h" 19 #include "drbd_req.h" 20 21 22 static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size); 23 24 static struct drbd_request *drbd_req_new(struct drbd_device *device, struct bio *bio_src) 25 { 26 struct drbd_request *req; 27 28 req = mempool_alloc(&drbd_request_mempool, GFP_NOIO); 29 if (!req) 30 return NULL; 31 memset(req, 0, sizeof(*req)); 32 33 req->private_bio = bio_clone_fast(bio_src, GFP_NOIO, &drbd_io_bio_set); 34 req->private_bio->bi_private = req; 35 req->private_bio->bi_end_io = drbd_request_endio; 36 37 req->rq_state = (bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0) 38 | (bio_op(bio_src) == REQ_OP_WRITE_SAME ? RQ_WSAME : 0) 39 | (bio_op(bio_src) == REQ_OP_WRITE_ZEROES ? RQ_ZEROES : 0) 40 | (bio_op(bio_src) == REQ_OP_DISCARD ? RQ_UNMAP : 0); 41 req->device = device; 42 req->master_bio = bio_src; 43 req->epoch = 0; 44 45 drbd_clear_interval(&req->i); 46 req->i.sector = bio_src->bi_iter.bi_sector; 47 req->i.size = bio_src->bi_iter.bi_size; 48 req->i.local = true; 49 req->i.waiting = false; 50 51 INIT_LIST_HEAD(&req->tl_requests); 52 INIT_LIST_HEAD(&req->w.list); 53 INIT_LIST_HEAD(&req->req_pending_master_completion); 54 INIT_LIST_HEAD(&req->req_pending_local); 55 56 /* one reference to be put by __drbd_make_request */ 57 atomic_set(&req->completion_ref, 1); 58 /* one kref as long as completion_ref > 0 */ 59 kref_init(&req->kref); 60 return req; 61 } 62 63 static void drbd_remove_request_interval(struct rb_root *root, 64 struct drbd_request *req) 65 { 66 struct drbd_device *device = req->device; 67 struct drbd_interval *i = &req->i; 68 69 drbd_remove_interval(root, i); 70 71 /* Wake up any processes waiting for this request to complete. */ 72 if (i->waiting) 73 wake_up(&device->misc_wait); 74 } 75 76 void drbd_req_destroy(struct kref *kref) 77 { 78 struct drbd_request *req = container_of(kref, struct drbd_request, kref); 79 struct drbd_device *device = req->device; 80 const unsigned s = req->rq_state; 81 82 if ((req->master_bio && !(s & RQ_POSTPONED)) || 83 atomic_read(&req->completion_ref) || 84 (s & RQ_LOCAL_PENDING) || 85 ((s & RQ_NET_MASK) && !(s & RQ_NET_DONE))) { 86 drbd_err(device, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n", 87 s, atomic_read(&req->completion_ref)); 88 return; 89 } 90 91 /* If called from mod_rq_state (expected normal case) or 92 * drbd_send_and_submit (the less likely normal path), this holds the 93 * req_lock, and req->tl_requests will typicaly be on ->transfer_log, 94 * though it may be still empty (never added to the transfer log). 95 * 96 * If called from do_retry(), we do NOT hold the req_lock, but we are 97 * still allowed to unconditionally list_del(&req->tl_requests), 98 * because it will be on a local on-stack list only. */ 99 list_del_init(&req->tl_requests); 100 101 /* finally remove the request from the conflict detection 102 * respective block_id verification interval tree. */ 103 if (!drbd_interval_empty(&req->i)) { 104 struct rb_root *root; 105 106 if (s & RQ_WRITE) 107 root = &device->write_requests; 108 else 109 root = &device->read_requests; 110 drbd_remove_request_interval(root, req); 111 } else if (s & (RQ_NET_MASK & ~RQ_NET_DONE) && req->i.size != 0) 112 drbd_err(device, "drbd_req_destroy: Logic BUG: interval empty, but: rq_state=0x%x, sect=%llu, size=%u\n", 113 s, (unsigned long long)req->i.sector, req->i.size); 114 115 /* if it was a write, we may have to set the corresponding 116 * bit(s) out-of-sync first. If it had a local part, we need to 117 * release the reference to the activity log. */ 118 if (s & RQ_WRITE) { 119 /* Set out-of-sync unless both OK flags are set 120 * (local only or remote failed). 121 * Other places where we set out-of-sync: 122 * READ with local io-error */ 123 124 /* There is a special case: 125 * we may notice late that IO was suspended, 126 * and postpone, or schedule for retry, a write, 127 * before it even was submitted or sent. 128 * In that case we do not want to touch the bitmap at all. 129 */ 130 if ((s & (RQ_POSTPONED|RQ_LOCAL_MASK|RQ_NET_MASK)) != RQ_POSTPONED) { 131 if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK)) 132 drbd_set_out_of_sync(device, req->i.sector, req->i.size); 133 134 if ((s & RQ_NET_OK) && (s & RQ_LOCAL_OK) && (s & RQ_NET_SIS)) 135 drbd_set_in_sync(device, req->i.sector, req->i.size); 136 } 137 138 /* one might be tempted to move the drbd_al_complete_io 139 * to the local io completion callback drbd_request_endio. 140 * but, if this was a mirror write, we may only 141 * drbd_al_complete_io after this is RQ_NET_DONE, 142 * otherwise the extent could be dropped from the al 143 * before it has actually been written on the peer. 144 * if we crash before our peer knows about the request, 145 * but after the extent has been dropped from the al, 146 * we would forget to resync the corresponding extent. 147 */ 148 if (s & RQ_IN_ACT_LOG) { 149 if (get_ldev_if_state(device, D_FAILED)) { 150 drbd_al_complete_io(device, &req->i); 151 put_ldev(device); 152 } else if (__ratelimit(&drbd_ratelimit_state)) { 153 drbd_warn(device, "Should have called drbd_al_complete_io(, %llu, %u), " 154 "but my Disk seems to have failed :(\n", 155 (unsigned long long) req->i.sector, req->i.size); 156 } 157 } 158 } 159 160 mempool_free(req, &drbd_request_mempool); 161 } 162 163 static void wake_all_senders(struct drbd_connection *connection) 164 { 165 wake_up(&connection->sender_work.q_wait); 166 } 167 168 /* must hold resource->req_lock */ 169 void start_new_tl_epoch(struct drbd_connection *connection) 170 { 171 /* no point closing an epoch, if it is empty, anyways. */ 172 if (connection->current_tle_writes == 0) 173 return; 174 175 connection->current_tle_writes = 0; 176 atomic_inc(&connection->current_tle_nr); 177 wake_all_senders(connection); 178 } 179 180 void complete_master_bio(struct drbd_device *device, 181 struct bio_and_error *m) 182 { 183 m->bio->bi_status = errno_to_blk_status(m->error); 184 bio_endio(m->bio); 185 dec_ap_bio(device); 186 } 187 188 189 /* Helper for __req_mod(). 190 * Set m->bio to the master bio, if it is fit to be completed, 191 * or leave it alone (it is initialized to NULL in __req_mod), 192 * if it has already been completed, or cannot be completed yet. 193 * If m->bio is set, the error status to be returned is placed in m->error. 194 */ 195 static 196 void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m) 197 { 198 const unsigned s = req->rq_state; 199 struct drbd_device *device = req->device; 200 int error, ok; 201 202 /* we must not complete the master bio, while it is 203 * still being processed by _drbd_send_zc_bio (drbd_send_dblock) 204 * not yet acknowledged by the peer 205 * not yet completed by the local io subsystem 206 * these flags may get cleared in any order by 207 * the worker, 208 * the receiver, 209 * the bio_endio completion callbacks. 210 */ 211 if ((s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) || 212 (s & RQ_NET_QUEUED) || (s & RQ_NET_PENDING) || 213 (s & RQ_COMPLETION_SUSP)) { 214 drbd_err(device, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s); 215 return; 216 } 217 218 if (!req->master_bio) { 219 drbd_err(device, "drbd_req_complete: Logic BUG, master_bio == NULL!\n"); 220 return; 221 } 222 223 /* 224 * figure out whether to report success or failure. 225 * 226 * report success when at least one of the operations succeeded. 227 * or, to put the other way, 228 * only report failure, when both operations failed. 229 * 230 * what to do about the failures is handled elsewhere. 231 * what we need to do here is just: complete the master_bio. 232 * 233 * local completion error, if any, has been stored as ERR_PTR 234 * in private_bio within drbd_request_endio. 235 */ 236 ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK); 237 error = PTR_ERR(req->private_bio); 238 239 /* Before we can signal completion to the upper layers, 240 * we may need to close the current transfer log epoch. 241 * We are within the request lock, so we can simply compare 242 * the request epoch number with the current transfer log 243 * epoch number. If they match, increase the current_tle_nr, 244 * and reset the transfer log epoch write_cnt. 245 */ 246 if (op_is_write(bio_op(req->master_bio)) && 247 req->epoch == atomic_read(&first_peer_device(device)->connection->current_tle_nr)) 248 start_new_tl_epoch(first_peer_device(device)->connection); 249 250 /* Update disk stats */ 251 bio_end_io_acct(req->master_bio, req->start_jif); 252 253 /* If READ failed, 254 * have it be pushed back to the retry work queue, 255 * so it will re-enter __drbd_make_request(), 256 * and be re-assigned to a suitable local or remote path, 257 * or failed if we do not have access to good data anymore. 258 * 259 * Unless it was failed early by __drbd_make_request(), 260 * because no path was available, in which case 261 * it was not even added to the transfer_log. 262 * 263 * read-ahead may fail, and will not be retried. 264 * 265 * WRITE should have used all available paths already. 266 */ 267 if (!ok && 268 bio_op(req->master_bio) == REQ_OP_READ && 269 !(req->master_bio->bi_opf & REQ_RAHEAD) && 270 !list_empty(&req->tl_requests)) 271 req->rq_state |= RQ_POSTPONED; 272 273 if (!(req->rq_state & RQ_POSTPONED)) { 274 m->error = ok ? 0 : (error ?: -EIO); 275 m->bio = req->master_bio; 276 req->master_bio = NULL; 277 /* We leave it in the tree, to be able to verify later 278 * write-acks in protocol != C during resync. 279 * But we mark it as "complete", so it won't be counted as 280 * conflict in a multi-primary setup. */ 281 req->i.completed = true; 282 } 283 284 if (req->i.waiting) 285 wake_up(&device->misc_wait); 286 287 /* Either we are about to complete to upper layers, 288 * or we will restart this request. 289 * In either case, the request object will be destroyed soon, 290 * so better remove it from all lists. */ 291 list_del_init(&req->req_pending_master_completion); 292 } 293 294 /* still holds resource->req_lock */ 295 static void drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put) 296 { 297 struct drbd_device *device = req->device; 298 D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED)); 299 300 if (!put) 301 return; 302 303 if (!atomic_sub_and_test(put, &req->completion_ref)) 304 return; 305 306 drbd_req_complete(req, m); 307 308 /* local completion may still come in later, 309 * we need to keep the req object around. */ 310 if (req->rq_state & RQ_LOCAL_ABORTED) 311 return; 312 313 if (req->rq_state & RQ_POSTPONED) { 314 /* don't destroy the req object just yet, 315 * but queue it for retry */ 316 drbd_restart_request(req); 317 return; 318 } 319 320 kref_put(&req->kref, drbd_req_destroy); 321 } 322 323 static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) 324 { 325 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 326 if (!connection) 327 return; 328 if (connection->req_next == NULL) 329 connection->req_next = req; 330 } 331 332 static void advance_conn_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) 333 { 334 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 335 if (!connection) 336 return; 337 if (connection->req_next != req) 338 return; 339 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { 340 const unsigned s = req->rq_state; 341 if (s & RQ_NET_QUEUED) 342 break; 343 } 344 if (&req->tl_requests == &connection->transfer_log) 345 req = NULL; 346 connection->req_next = req; 347 } 348 349 static void set_if_null_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req) 350 { 351 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 352 if (!connection) 353 return; 354 if (connection->req_ack_pending == NULL) 355 connection->req_ack_pending = req; 356 } 357 358 static void advance_conn_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req) 359 { 360 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 361 if (!connection) 362 return; 363 if (connection->req_ack_pending != req) 364 return; 365 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { 366 const unsigned s = req->rq_state; 367 if ((s & RQ_NET_SENT) && (s & RQ_NET_PENDING)) 368 break; 369 } 370 if (&req->tl_requests == &connection->transfer_log) 371 req = NULL; 372 connection->req_ack_pending = req; 373 } 374 375 static void set_if_null_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req) 376 { 377 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 378 if (!connection) 379 return; 380 if (connection->req_not_net_done == NULL) 381 connection->req_not_net_done = req; 382 } 383 384 static void advance_conn_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req) 385 { 386 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 387 if (!connection) 388 return; 389 if (connection->req_not_net_done != req) 390 return; 391 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { 392 const unsigned s = req->rq_state; 393 if ((s & RQ_NET_SENT) && !(s & RQ_NET_DONE)) 394 break; 395 } 396 if (&req->tl_requests == &connection->transfer_log) 397 req = NULL; 398 connection->req_not_net_done = req; 399 } 400 401 /* I'd like this to be the only place that manipulates 402 * req->completion_ref and req->kref. */ 403 static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m, 404 int clear, int set) 405 { 406 struct drbd_device *device = req->device; 407 struct drbd_peer_device *peer_device = first_peer_device(device); 408 unsigned s = req->rq_state; 409 int c_put = 0; 410 411 if (drbd_suspended(device) && !((s | clear) & RQ_COMPLETION_SUSP)) 412 set |= RQ_COMPLETION_SUSP; 413 414 /* apply */ 415 416 req->rq_state &= ~clear; 417 req->rq_state |= set; 418 419 /* no change? */ 420 if (req->rq_state == s) 421 return; 422 423 /* intent: get references */ 424 425 kref_get(&req->kref); 426 427 if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING)) 428 atomic_inc(&req->completion_ref); 429 430 if (!(s & RQ_NET_PENDING) && (set & RQ_NET_PENDING)) { 431 inc_ap_pending(device); 432 atomic_inc(&req->completion_ref); 433 } 434 435 if (!(s & RQ_NET_QUEUED) && (set & RQ_NET_QUEUED)) { 436 atomic_inc(&req->completion_ref); 437 set_if_null_req_next(peer_device, req); 438 } 439 440 if (!(s & RQ_EXP_BARR_ACK) && (set & RQ_EXP_BARR_ACK)) 441 kref_get(&req->kref); /* wait for the DONE */ 442 443 if (!(s & RQ_NET_SENT) && (set & RQ_NET_SENT)) { 444 /* potentially already completed in the ack_receiver thread */ 445 if (!(s & RQ_NET_DONE)) { 446 atomic_add(req->i.size >> 9, &device->ap_in_flight); 447 set_if_null_req_not_net_done(peer_device, req); 448 } 449 if (req->rq_state & RQ_NET_PENDING) 450 set_if_null_req_ack_pending(peer_device, req); 451 } 452 453 if (!(s & RQ_COMPLETION_SUSP) && (set & RQ_COMPLETION_SUSP)) 454 atomic_inc(&req->completion_ref); 455 456 /* progress: put references */ 457 458 if ((s & RQ_COMPLETION_SUSP) && (clear & RQ_COMPLETION_SUSP)) 459 ++c_put; 460 461 if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) { 462 D_ASSERT(device, req->rq_state & RQ_LOCAL_PENDING); 463 ++c_put; 464 } 465 466 if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) { 467 if (req->rq_state & RQ_LOCAL_ABORTED) 468 kref_put(&req->kref, drbd_req_destroy); 469 else 470 ++c_put; 471 list_del_init(&req->req_pending_local); 472 } 473 474 if ((s & RQ_NET_PENDING) && (clear & RQ_NET_PENDING)) { 475 dec_ap_pending(device); 476 ++c_put; 477 req->acked_jif = jiffies; 478 advance_conn_req_ack_pending(peer_device, req); 479 } 480 481 if ((s & RQ_NET_QUEUED) && (clear & RQ_NET_QUEUED)) { 482 ++c_put; 483 advance_conn_req_next(peer_device, req); 484 } 485 486 if (!(s & RQ_NET_DONE) && (set & RQ_NET_DONE)) { 487 if (s & RQ_NET_SENT) 488 atomic_sub(req->i.size >> 9, &device->ap_in_flight); 489 if (s & RQ_EXP_BARR_ACK) 490 kref_put(&req->kref, drbd_req_destroy); 491 req->net_done_jif = jiffies; 492 493 /* in ahead/behind mode, or just in case, 494 * before we finally destroy this request, 495 * the caching pointers must not reference it anymore */ 496 advance_conn_req_next(peer_device, req); 497 advance_conn_req_ack_pending(peer_device, req); 498 advance_conn_req_not_net_done(peer_device, req); 499 } 500 501 /* potentially complete and destroy */ 502 503 /* If we made progress, retry conflicting peer requests, if any. */ 504 if (req->i.waiting) 505 wake_up(&device->misc_wait); 506 507 drbd_req_put_completion_ref(req, m, c_put); 508 kref_put(&req->kref, drbd_req_destroy); 509 } 510 511 static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req) 512 { 513 char b[BDEVNAME_SIZE]; 514 515 if (!__ratelimit(&drbd_ratelimit_state)) 516 return; 517 518 drbd_warn(device, "local %s IO error sector %llu+%u on %s\n", 519 (req->rq_state & RQ_WRITE) ? "WRITE" : "READ", 520 (unsigned long long)req->i.sector, 521 req->i.size >> 9, 522 bdevname(device->ldev->backing_bdev, b)); 523 } 524 525 /* Helper for HANDED_OVER_TO_NETWORK. 526 * Is this a protocol A write (neither WRITE_ACK nor RECEIVE_ACK expected)? 527 * Is it also still "PENDING"? 528 * --> If so, clear PENDING and set NET_OK below. 529 * If it is a protocol A write, but not RQ_PENDING anymore, neg-ack was faster 530 * (and we must not set RQ_NET_OK) */ 531 static inline bool is_pending_write_protocol_A(struct drbd_request *req) 532 { 533 return (req->rq_state & 534 (RQ_WRITE|RQ_NET_PENDING|RQ_EXP_WRITE_ACK|RQ_EXP_RECEIVE_ACK)) 535 == (RQ_WRITE|RQ_NET_PENDING); 536 } 537 538 /* obviously this could be coded as many single functions 539 * instead of one huge switch, 540 * or by putting the code directly in the respective locations 541 * (as it has been before). 542 * 543 * but having it this way 544 * enforces that it is all in this one place, where it is easier to audit, 545 * it makes it obvious that whatever "event" "happens" to a request should 546 * happen "atomically" within the req_lock, 547 * and it enforces that we have to think in a very structured manner 548 * about the "events" that may happen to a request during its life time ... 549 */ 550 int __req_mod(struct drbd_request *req, enum drbd_req_event what, 551 struct bio_and_error *m) 552 { 553 struct drbd_device *const device = req->device; 554 struct drbd_peer_device *const peer_device = first_peer_device(device); 555 struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL; 556 struct net_conf *nc; 557 int p, rv = 0; 558 559 if (m) 560 m->bio = NULL; 561 562 switch (what) { 563 default: 564 drbd_err(device, "LOGIC BUG in %s:%u\n", __FILE__ , __LINE__); 565 break; 566 567 /* does not happen... 568 * initialization done in drbd_req_new 569 case CREATED: 570 break; 571 */ 572 573 case TO_BE_SENT: /* via network */ 574 /* reached via __drbd_make_request 575 * and from w_read_retry_remote */ 576 D_ASSERT(device, !(req->rq_state & RQ_NET_MASK)); 577 rcu_read_lock(); 578 nc = rcu_dereference(connection->net_conf); 579 p = nc->wire_protocol; 580 rcu_read_unlock(); 581 req->rq_state |= 582 p == DRBD_PROT_C ? RQ_EXP_WRITE_ACK : 583 p == DRBD_PROT_B ? RQ_EXP_RECEIVE_ACK : 0; 584 mod_rq_state(req, m, 0, RQ_NET_PENDING); 585 break; 586 587 case TO_BE_SUBMITTED: /* locally */ 588 /* reached via __drbd_make_request */ 589 D_ASSERT(device, !(req->rq_state & RQ_LOCAL_MASK)); 590 mod_rq_state(req, m, 0, RQ_LOCAL_PENDING); 591 break; 592 593 case COMPLETED_OK: 594 if (req->rq_state & RQ_WRITE) 595 device->writ_cnt += req->i.size >> 9; 596 else 597 device->read_cnt += req->i.size >> 9; 598 599 mod_rq_state(req, m, RQ_LOCAL_PENDING, 600 RQ_LOCAL_COMPLETED|RQ_LOCAL_OK); 601 break; 602 603 case ABORT_DISK_IO: 604 mod_rq_state(req, m, 0, RQ_LOCAL_ABORTED); 605 break; 606 607 case WRITE_COMPLETED_WITH_ERROR: 608 drbd_report_io_error(device, req); 609 __drbd_chk_io_error(device, DRBD_WRITE_ERROR); 610 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED); 611 break; 612 613 case READ_COMPLETED_WITH_ERROR: 614 drbd_set_out_of_sync(device, req->i.sector, req->i.size); 615 drbd_report_io_error(device, req); 616 __drbd_chk_io_error(device, DRBD_READ_ERROR); 617 fallthrough; 618 case READ_AHEAD_COMPLETED_WITH_ERROR: 619 /* it is legal to fail read-ahead, no __drbd_chk_io_error in that case. */ 620 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED); 621 break; 622 623 case DISCARD_COMPLETED_NOTSUPP: 624 case DISCARD_COMPLETED_WITH_ERROR: 625 /* I'd rather not detach from local disk just because it 626 * failed a REQ_OP_DISCARD. */ 627 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED); 628 break; 629 630 case QUEUE_FOR_NET_READ: 631 /* READ, and 632 * no local disk, 633 * or target area marked as invalid, 634 * or just got an io-error. */ 635 /* from __drbd_make_request 636 * or from bio_endio during read io-error recovery */ 637 638 /* So we can verify the handle in the answer packet. 639 * Corresponding drbd_remove_request_interval is in 640 * drbd_req_complete() */ 641 D_ASSERT(device, drbd_interval_empty(&req->i)); 642 drbd_insert_interval(&device->read_requests, &req->i); 643 644 set_bit(UNPLUG_REMOTE, &device->flags); 645 646 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 647 D_ASSERT(device, (req->rq_state & RQ_LOCAL_MASK) == 0); 648 mod_rq_state(req, m, 0, RQ_NET_QUEUED); 649 req->w.cb = w_send_read_req; 650 drbd_queue_work(&connection->sender_work, 651 &req->w); 652 break; 653 654 case QUEUE_FOR_NET_WRITE: 655 /* assert something? */ 656 /* from __drbd_make_request only */ 657 658 /* Corresponding drbd_remove_request_interval is in 659 * drbd_req_complete() */ 660 D_ASSERT(device, drbd_interval_empty(&req->i)); 661 drbd_insert_interval(&device->write_requests, &req->i); 662 663 /* NOTE 664 * In case the req ended up on the transfer log before being 665 * queued on the worker, it could lead to this request being 666 * missed during cleanup after connection loss. 667 * So we have to do both operations here, 668 * within the same lock that protects the transfer log. 669 * 670 * _req_add_to_epoch(req); this has to be after the 671 * _maybe_start_new_epoch(req); which happened in 672 * __drbd_make_request, because we now may set the bit 673 * again ourselves to close the current epoch. 674 * 675 * Add req to the (now) current epoch (barrier). */ 676 677 /* otherwise we may lose an unplug, which may cause some remote 678 * io-scheduler timeout to expire, increasing maximum latency, 679 * hurting performance. */ 680 set_bit(UNPLUG_REMOTE, &device->flags); 681 682 /* queue work item to send data */ 683 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 684 mod_rq_state(req, m, 0, RQ_NET_QUEUED|RQ_EXP_BARR_ACK); 685 req->w.cb = w_send_dblock; 686 drbd_queue_work(&connection->sender_work, 687 &req->w); 688 689 /* close the epoch, in case it outgrew the limit */ 690 rcu_read_lock(); 691 nc = rcu_dereference(connection->net_conf); 692 p = nc->max_epoch_size; 693 rcu_read_unlock(); 694 if (connection->current_tle_writes >= p) 695 start_new_tl_epoch(connection); 696 697 break; 698 699 case QUEUE_FOR_SEND_OOS: 700 mod_rq_state(req, m, 0, RQ_NET_QUEUED); 701 req->w.cb = w_send_out_of_sync; 702 drbd_queue_work(&connection->sender_work, 703 &req->w); 704 break; 705 706 case READ_RETRY_REMOTE_CANCELED: 707 case SEND_CANCELED: 708 case SEND_FAILED: 709 /* real cleanup will be done from tl_clear. just update flags 710 * so it is no longer marked as on the worker queue */ 711 mod_rq_state(req, m, RQ_NET_QUEUED, 0); 712 break; 713 714 case HANDED_OVER_TO_NETWORK: 715 /* assert something? */ 716 if (is_pending_write_protocol_A(req)) 717 /* this is what is dangerous about protocol A: 718 * pretend it was successfully written on the peer. */ 719 mod_rq_state(req, m, RQ_NET_QUEUED|RQ_NET_PENDING, 720 RQ_NET_SENT|RQ_NET_OK); 721 else 722 mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_SENT); 723 /* It is still not yet RQ_NET_DONE until the 724 * corresponding epoch barrier got acked as well, 725 * so we know what to dirty on connection loss. */ 726 break; 727 728 case OOS_HANDED_TO_NETWORK: 729 /* Was not set PENDING, no longer QUEUED, so is now DONE 730 * as far as this connection is concerned. */ 731 mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_DONE); 732 break; 733 734 case CONNECTION_LOST_WHILE_PENDING: 735 /* transfer log cleanup after connection loss */ 736 mod_rq_state(req, m, 737 RQ_NET_OK|RQ_NET_PENDING|RQ_COMPLETION_SUSP, 738 RQ_NET_DONE); 739 break; 740 741 case CONFLICT_RESOLVED: 742 /* for superseded conflicting writes of multiple primaries, 743 * there is no need to keep anything in the tl, potential 744 * node crashes are covered by the activity log. 745 * 746 * If this request had been marked as RQ_POSTPONED before, 747 * it will actually not be completed, but "restarted", 748 * resubmitted from the retry worker context. */ 749 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 750 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK); 751 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_DONE|RQ_NET_OK); 752 break; 753 754 case WRITE_ACKED_BY_PEER_AND_SIS: 755 req->rq_state |= RQ_NET_SIS; 756 case WRITE_ACKED_BY_PEER: 757 /* Normal operation protocol C: successfully written on peer. 758 * During resync, even in protocol != C, 759 * we requested an explicit write ack anyways. 760 * Which means we cannot even assert anything here. 761 * Nothing more to do here. 762 * We want to keep the tl in place for all protocols, to cater 763 * for volatile write-back caches on lower level devices. */ 764 goto ack_common; 765 case RECV_ACKED_BY_PEER: 766 D_ASSERT(device, req->rq_state & RQ_EXP_RECEIVE_ACK); 767 /* protocol B; pretends to be successfully written on peer. 768 * see also notes above in HANDED_OVER_TO_NETWORK about 769 * protocol != C */ 770 ack_common: 771 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK); 772 break; 773 774 case POSTPONE_WRITE: 775 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK); 776 /* If this node has already detected the write conflict, the 777 * worker will be waiting on misc_wait. Wake it up once this 778 * request has completed locally. 779 */ 780 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 781 req->rq_state |= RQ_POSTPONED; 782 if (req->i.waiting) 783 wake_up(&device->misc_wait); 784 /* Do not clear RQ_NET_PENDING. This request will make further 785 * progress via restart_conflicting_writes() or 786 * fail_postponed_requests(). Hopefully. */ 787 break; 788 789 case NEG_ACKED: 790 mod_rq_state(req, m, RQ_NET_OK|RQ_NET_PENDING, 0); 791 break; 792 793 case FAIL_FROZEN_DISK_IO: 794 if (!(req->rq_state & RQ_LOCAL_COMPLETED)) 795 break; 796 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0); 797 break; 798 799 case RESTART_FROZEN_DISK_IO: 800 if (!(req->rq_state & RQ_LOCAL_COMPLETED)) 801 break; 802 803 mod_rq_state(req, m, 804 RQ_COMPLETION_SUSP|RQ_LOCAL_COMPLETED, 805 RQ_LOCAL_PENDING); 806 807 rv = MR_READ; 808 if (bio_data_dir(req->master_bio) == WRITE) 809 rv = MR_WRITE; 810 811 get_ldev(device); /* always succeeds in this call path */ 812 req->w.cb = w_restart_disk_io; 813 drbd_queue_work(&connection->sender_work, 814 &req->w); 815 break; 816 817 case RESEND: 818 /* Simply complete (local only) READs. */ 819 if (!(req->rq_state & RQ_WRITE) && !req->w.cb) { 820 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0); 821 break; 822 } 823 824 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK 825 before the connection loss (B&C only); only P_BARRIER_ACK 826 (or the local completion?) was missing when we suspended. 827 Throwing them out of the TL here by pretending we got a BARRIER_ACK. 828 During connection handshake, we ensure that the peer was not rebooted. */ 829 if (!(req->rq_state & RQ_NET_OK)) { 830 /* FIXME could this possibly be a req->dw.cb == w_send_out_of_sync? 831 * in that case we must not set RQ_NET_PENDING. */ 832 833 mod_rq_state(req, m, RQ_COMPLETION_SUSP, RQ_NET_QUEUED|RQ_NET_PENDING); 834 if (req->w.cb) { 835 /* w.cb expected to be w_send_dblock, or w_send_read_req */ 836 drbd_queue_work(&connection->sender_work, 837 &req->w); 838 rv = req->rq_state & RQ_WRITE ? MR_WRITE : MR_READ; 839 } /* else: FIXME can this happen? */ 840 break; 841 } 842 fallthrough; /* to BARRIER_ACKED */ 843 844 case BARRIER_ACKED: 845 /* barrier ack for READ requests does not make sense */ 846 if (!(req->rq_state & RQ_WRITE)) 847 break; 848 849 if (req->rq_state & RQ_NET_PENDING) { 850 /* barrier came in before all requests were acked. 851 * this is bad, because if the connection is lost now, 852 * we won't be able to clean them up... */ 853 drbd_err(device, "FIXME (BARRIER_ACKED but pending)\n"); 854 } 855 /* Allowed to complete requests, even while suspended. 856 * As this is called for all requests within a matching epoch, 857 * we need to filter, and only set RQ_NET_DONE for those that 858 * have actually been on the wire. */ 859 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 860 (req->rq_state & RQ_NET_MASK) ? RQ_NET_DONE : 0); 861 break; 862 863 case DATA_RECEIVED: 864 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 865 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE); 866 break; 867 868 case QUEUE_AS_DRBD_BARRIER: 869 start_new_tl_epoch(connection); 870 mod_rq_state(req, m, 0, RQ_NET_OK|RQ_NET_DONE); 871 break; 872 } 873 874 return rv; 875 } 876 877 /* we may do a local read if: 878 * - we are consistent (of course), 879 * - or we are generally inconsistent, 880 * BUT we are still/already IN SYNC for this area. 881 * since size may be bigger than BM_BLOCK_SIZE, 882 * we may need to check several bits. 883 */ 884 static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size) 885 { 886 unsigned long sbnr, ebnr; 887 sector_t esector, nr_sectors; 888 889 if (device->state.disk == D_UP_TO_DATE) 890 return true; 891 if (device->state.disk != D_INCONSISTENT) 892 return false; 893 esector = sector + (size >> 9) - 1; 894 nr_sectors = get_capacity(device->vdisk); 895 D_ASSERT(device, sector < nr_sectors); 896 D_ASSERT(device, esector < nr_sectors); 897 898 sbnr = BM_SECT_TO_BIT(sector); 899 ebnr = BM_SECT_TO_BIT(esector); 900 901 return drbd_bm_count_bits(device, sbnr, ebnr) == 0; 902 } 903 904 static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t sector, 905 enum drbd_read_balancing rbm) 906 { 907 struct backing_dev_info *bdi; 908 int stripe_shift; 909 910 switch (rbm) { 911 case RB_CONGESTED_REMOTE: 912 bdi = device->ldev->backing_bdev->bd_disk->queue->backing_dev_info; 913 return bdi_read_congested(bdi); 914 case RB_LEAST_PENDING: 915 return atomic_read(&device->local_cnt) > 916 atomic_read(&device->ap_pending_cnt) + atomic_read(&device->rs_pending_cnt); 917 case RB_32K_STRIPING: /* stripe_shift = 15 */ 918 case RB_64K_STRIPING: 919 case RB_128K_STRIPING: 920 case RB_256K_STRIPING: 921 case RB_512K_STRIPING: 922 case RB_1M_STRIPING: /* stripe_shift = 20 */ 923 stripe_shift = (rbm - RB_32K_STRIPING + 15); 924 return (sector >> (stripe_shift - 9)) & 1; 925 case RB_ROUND_ROBIN: 926 return test_and_change_bit(READ_BALANCE_RR, &device->flags); 927 case RB_PREFER_REMOTE: 928 return true; 929 case RB_PREFER_LOCAL: 930 default: 931 return false; 932 } 933 } 934 935 /* 936 * complete_conflicting_writes - wait for any conflicting write requests 937 * 938 * The write_requests tree contains all active write requests which we 939 * currently know about. Wait for any requests to complete which conflict with 940 * the new one. 941 * 942 * Only way out: remove the conflicting intervals from the tree. 943 */ 944 static void complete_conflicting_writes(struct drbd_request *req) 945 { 946 DEFINE_WAIT(wait); 947 struct drbd_device *device = req->device; 948 struct drbd_interval *i; 949 sector_t sector = req->i.sector; 950 int size = req->i.size; 951 952 for (;;) { 953 drbd_for_each_overlap(i, &device->write_requests, sector, size) { 954 /* Ignore, if already completed to upper layers. */ 955 if (i->completed) 956 continue; 957 /* Handle the first found overlap. After the schedule 958 * we have to restart the tree walk. */ 959 break; 960 } 961 if (!i) /* if any */ 962 break; 963 964 /* Indicate to wake up device->misc_wait on progress. */ 965 prepare_to_wait(&device->misc_wait, &wait, TASK_UNINTERRUPTIBLE); 966 i->waiting = true; 967 spin_unlock_irq(&device->resource->req_lock); 968 schedule(); 969 spin_lock_irq(&device->resource->req_lock); 970 } 971 finish_wait(&device->misc_wait, &wait); 972 } 973 974 /* called within req_lock */ 975 static void maybe_pull_ahead(struct drbd_device *device) 976 { 977 struct drbd_connection *connection = first_peer_device(device)->connection; 978 struct net_conf *nc; 979 bool congested = false; 980 enum drbd_on_congestion on_congestion; 981 982 rcu_read_lock(); 983 nc = rcu_dereference(connection->net_conf); 984 on_congestion = nc ? nc->on_congestion : OC_BLOCK; 985 rcu_read_unlock(); 986 if (on_congestion == OC_BLOCK || 987 connection->agreed_pro_version < 96) 988 return; 989 990 if (on_congestion == OC_PULL_AHEAD && device->state.conn == C_AHEAD) 991 return; /* nothing to do ... */ 992 993 /* If I don't even have good local storage, we can not reasonably try 994 * to pull ahead of the peer. We also need the local reference to make 995 * sure device->act_log is there. 996 */ 997 if (!get_ldev_if_state(device, D_UP_TO_DATE)) 998 return; 999 1000 if (nc->cong_fill && 1001 atomic_read(&device->ap_in_flight) >= nc->cong_fill) { 1002 drbd_info(device, "Congestion-fill threshold reached\n"); 1003 congested = true; 1004 } 1005 1006 if (device->act_log->used >= nc->cong_extents) { 1007 drbd_info(device, "Congestion-extents threshold reached\n"); 1008 congested = true; 1009 } 1010 1011 if (congested) { 1012 /* start a new epoch for non-mirrored writes */ 1013 start_new_tl_epoch(first_peer_device(device)->connection); 1014 1015 if (on_congestion == OC_PULL_AHEAD) 1016 _drbd_set_state(_NS(device, conn, C_AHEAD), 0, NULL); 1017 else /*nc->on_congestion == OC_DISCONNECT */ 1018 _drbd_set_state(_NS(device, conn, C_DISCONNECTING), 0, NULL); 1019 } 1020 put_ldev(device); 1021 } 1022 1023 /* If this returns false, and req->private_bio is still set, 1024 * this should be submitted locally. 1025 * 1026 * If it returns false, but req->private_bio is not set, 1027 * we do not have access to good data :( 1028 * 1029 * Otherwise, this destroys req->private_bio, if any, 1030 * and returns true. 1031 */ 1032 static bool do_remote_read(struct drbd_request *req) 1033 { 1034 struct drbd_device *device = req->device; 1035 enum drbd_read_balancing rbm; 1036 1037 if (req->private_bio) { 1038 if (!drbd_may_do_local_read(device, 1039 req->i.sector, req->i.size)) { 1040 bio_put(req->private_bio); 1041 req->private_bio = NULL; 1042 put_ldev(device); 1043 } 1044 } 1045 1046 if (device->state.pdsk != D_UP_TO_DATE) 1047 return false; 1048 1049 if (req->private_bio == NULL) 1050 return true; 1051 1052 /* TODO: improve read balancing decisions, take into account drbd 1053 * protocol, pending requests etc. */ 1054 1055 rcu_read_lock(); 1056 rbm = rcu_dereference(device->ldev->disk_conf)->read_balancing; 1057 rcu_read_unlock(); 1058 1059 if (rbm == RB_PREFER_LOCAL && req->private_bio) 1060 return false; /* submit locally */ 1061 1062 if (remote_due_to_read_balancing(device, req->i.sector, rbm)) { 1063 if (req->private_bio) { 1064 bio_put(req->private_bio); 1065 req->private_bio = NULL; 1066 put_ldev(device); 1067 } 1068 return true; 1069 } 1070 1071 return false; 1072 } 1073 1074 bool drbd_should_do_remote(union drbd_dev_state s) 1075 { 1076 return s.pdsk == D_UP_TO_DATE || 1077 (s.pdsk >= D_INCONSISTENT && 1078 s.conn >= C_WF_BITMAP_T && 1079 s.conn < C_AHEAD); 1080 /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T. 1081 That is equivalent since before 96 IO was frozen in the C_WF_BITMAP* 1082 states. */ 1083 } 1084 1085 static bool drbd_should_send_out_of_sync(union drbd_dev_state s) 1086 { 1087 return s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S; 1088 /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary 1089 since we enter state C_AHEAD only if proto >= 96 */ 1090 } 1091 1092 /* returns number of connections (== 1, for drbd 8.4) 1093 * expected to actually write this data, 1094 * which does NOT include those that we are L_AHEAD for. */ 1095 static int drbd_process_write_request(struct drbd_request *req) 1096 { 1097 struct drbd_device *device = req->device; 1098 int remote, send_oos; 1099 1100 remote = drbd_should_do_remote(device->state); 1101 send_oos = drbd_should_send_out_of_sync(device->state); 1102 1103 /* Need to replicate writes. Unless it is an empty flush, 1104 * which is better mapped to a DRBD P_BARRIER packet, 1105 * also for drbd wire protocol compatibility reasons. 1106 * If this was a flush, just start a new epoch. 1107 * Unless the current epoch was empty anyways, or we are not currently 1108 * replicating, in which case there is no point. */ 1109 if (unlikely(req->i.size == 0)) { 1110 /* The only size==0 bios we expect are empty flushes. */ 1111 D_ASSERT(device, req->master_bio->bi_opf & REQ_PREFLUSH); 1112 if (remote) 1113 _req_mod(req, QUEUE_AS_DRBD_BARRIER); 1114 return remote; 1115 } 1116 1117 if (!remote && !send_oos) 1118 return 0; 1119 1120 D_ASSERT(device, !(remote && send_oos)); 1121 1122 if (remote) { 1123 _req_mod(req, TO_BE_SENT); 1124 _req_mod(req, QUEUE_FOR_NET_WRITE); 1125 } else if (drbd_set_out_of_sync(device, req->i.sector, req->i.size)) 1126 _req_mod(req, QUEUE_FOR_SEND_OOS); 1127 1128 return remote; 1129 } 1130 1131 static void drbd_process_discard_or_zeroes_req(struct drbd_request *req, int flags) 1132 { 1133 int err = drbd_issue_discard_or_zero_out(req->device, 1134 req->i.sector, req->i.size >> 9, flags); 1135 if (err) 1136 req->private_bio->bi_status = BLK_STS_IOERR; 1137 bio_endio(req->private_bio); 1138 } 1139 1140 static void 1141 drbd_submit_req_private_bio(struct drbd_request *req) 1142 { 1143 struct drbd_device *device = req->device; 1144 struct bio *bio = req->private_bio; 1145 unsigned int type; 1146 1147 if (bio_op(bio) != REQ_OP_READ) 1148 type = DRBD_FAULT_DT_WR; 1149 else if (bio->bi_opf & REQ_RAHEAD) 1150 type = DRBD_FAULT_DT_RA; 1151 else 1152 type = DRBD_FAULT_DT_RD; 1153 1154 bio_set_dev(bio, device->ldev->backing_bdev); 1155 1156 /* State may have changed since we grabbed our reference on the 1157 * ->ldev member. Double check, and short-circuit to endio. 1158 * In case the last activity log transaction failed to get on 1159 * stable storage, and this is a WRITE, we may not even submit 1160 * this bio. */ 1161 if (get_ldev(device)) { 1162 if (drbd_insert_fault(device, type)) 1163 bio_io_error(bio); 1164 else if (bio_op(bio) == REQ_OP_WRITE_ZEROES) 1165 drbd_process_discard_or_zeroes_req(req, EE_ZEROOUT | 1166 ((bio->bi_opf & REQ_NOUNMAP) ? 0 : EE_TRIM)); 1167 else if (bio_op(bio) == REQ_OP_DISCARD) 1168 drbd_process_discard_or_zeroes_req(req, EE_TRIM); 1169 else 1170 submit_bio_noacct(bio); 1171 put_ldev(device); 1172 } else 1173 bio_io_error(bio); 1174 } 1175 1176 static void drbd_queue_write(struct drbd_device *device, struct drbd_request *req) 1177 { 1178 spin_lock_irq(&device->resource->req_lock); 1179 list_add_tail(&req->tl_requests, &device->submit.writes); 1180 list_add_tail(&req->req_pending_master_completion, 1181 &device->pending_master_completion[1 /* WRITE */]); 1182 spin_unlock_irq(&device->resource->req_lock); 1183 queue_work(device->submit.wq, &device->submit.worker); 1184 /* do_submit() may sleep internally on al_wait, too */ 1185 wake_up(&device->al_wait); 1186 } 1187 1188 /* returns the new drbd_request pointer, if the caller is expected to 1189 * drbd_send_and_submit() it (to save latency), or NULL if we queued the 1190 * request on the submitter thread. 1191 * Returns ERR_PTR(-ENOMEM) if we cannot allocate a drbd_request. 1192 */ 1193 static struct drbd_request * 1194 drbd_request_prepare(struct drbd_device *device, struct bio *bio) 1195 { 1196 const int rw = bio_data_dir(bio); 1197 struct drbd_request *req; 1198 1199 /* allocate outside of all locks; */ 1200 req = drbd_req_new(device, bio); 1201 if (!req) { 1202 dec_ap_bio(device); 1203 /* only pass the error to the upper layers. 1204 * if user cannot handle io errors, that's not our business. */ 1205 drbd_err(device, "could not kmalloc() req\n"); 1206 bio->bi_status = BLK_STS_RESOURCE; 1207 bio_endio(bio); 1208 return ERR_PTR(-ENOMEM); 1209 } 1210 1211 /* Update disk stats */ 1212 req->start_jif = bio_start_io_acct(req->master_bio); 1213 1214 if (!get_ldev(device)) { 1215 bio_put(req->private_bio); 1216 req->private_bio = NULL; 1217 } 1218 1219 /* process discards always from our submitter thread */ 1220 if (bio_op(bio) == REQ_OP_WRITE_ZEROES || 1221 bio_op(bio) == REQ_OP_DISCARD) 1222 goto queue_for_submitter_thread; 1223 1224 if (rw == WRITE && req->private_bio && req->i.size 1225 && !test_bit(AL_SUSPENDED, &device->flags)) { 1226 if (!drbd_al_begin_io_fastpath(device, &req->i)) 1227 goto queue_for_submitter_thread; 1228 req->rq_state |= RQ_IN_ACT_LOG; 1229 req->in_actlog_jif = jiffies; 1230 } 1231 return req; 1232 1233 queue_for_submitter_thread: 1234 atomic_inc(&device->ap_actlog_cnt); 1235 drbd_queue_write(device, req); 1236 return NULL; 1237 } 1238 1239 /* Require at least one path to current data. 1240 * We don't want to allow writes on C_STANDALONE D_INCONSISTENT: 1241 * We would not allow to read what was written, 1242 * we would not have bumped the data generation uuids, 1243 * we would cause data divergence for all the wrong reasons. 1244 * 1245 * If we don't see at least one D_UP_TO_DATE, we will fail this request, 1246 * which either returns EIO, or, if OND_SUSPEND_IO is set, suspends IO, 1247 * and queues for retry later. 1248 */ 1249 static bool may_do_writes(struct drbd_device *device) 1250 { 1251 const union drbd_dev_state s = device->state; 1252 return s.disk == D_UP_TO_DATE || s.pdsk == D_UP_TO_DATE; 1253 } 1254 1255 struct drbd_plug_cb { 1256 struct blk_plug_cb cb; 1257 struct drbd_request *most_recent_req; 1258 /* do we need more? */ 1259 }; 1260 1261 static void drbd_unplug(struct blk_plug_cb *cb, bool from_schedule) 1262 { 1263 struct drbd_plug_cb *plug = container_of(cb, struct drbd_plug_cb, cb); 1264 struct drbd_resource *resource = plug->cb.data; 1265 struct drbd_request *req = plug->most_recent_req; 1266 1267 kfree(cb); 1268 if (!req) 1269 return; 1270 1271 spin_lock_irq(&resource->req_lock); 1272 /* In case the sender did not process it yet, raise the flag to 1273 * have it followed with P_UNPLUG_REMOTE just after. */ 1274 req->rq_state |= RQ_UNPLUG; 1275 /* but also queue a generic unplug */ 1276 drbd_queue_unplug(req->device); 1277 kref_put(&req->kref, drbd_req_destroy); 1278 spin_unlock_irq(&resource->req_lock); 1279 } 1280 1281 static struct drbd_plug_cb* drbd_check_plugged(struct drbd_resource *resource) 1282 { 1283 /* A lot of text to say 1284 * return (struct drbd_plug_cb*)blk_check_plugged(); */ 1285 struct drbd_plug_cb *plug; 1286 struct blk_plug_cb *cb = blk_check_plugged(drbd_unplug, resource, sizeof(*plug)); 1287 1288 if (cb) 1289 plug = container_of(cb, struct drbd_plug_cb, cb); 1290 else 1291 plug = NULL; 1292 return plug; 1293 } 1294 1295 static void drbd_update_plug(struct drbd_plug_cb *plug, struct drbd_request *req) 1296 { 1297 struct drbd_request *tmp = plug->most_recent_req; 1298 /* Will be sent to some peer. 1299 * Remember to tag it with UNPLUG_REMOTE on unplug */ 1300 kref_get(&req->kref); 1301 plug->most_recent_req = req; 1302 if (tmp) 1303 kref_put(&tmp->kref, drbd_req_destroy); 1304 } 1305 1306 static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request *req) 1307 { 1308 struct drbd_resource *resource = device->resource; 1309 const int rw = bio_data_dir(req->master_bio); 1310 struct bio_and_error m = { NULL, }; 1311 bool no_remote = false; 1312 bool submit_private_bio = false; 1313 1314 spin_lock_irq(&resource->req_lock); 1315 if (rw == WRITE) { 1316 /* This may temporarily give up the req_lock, 1317 * but will re-aquire it before it returns here. 1318 * Needs to be before the check on drbd_suspended() */ 1319 complete_conflicting_writes(req); 1320 /* no more giving up req_lock from now on! */ 1321 1322 /* check for congestion, and potentially stop sending 1323 * full data updates, but start sending "dirty bits" only. */ 1324 maybe_pull_ahead(device); 1325 } 1326 1327 1328 if (drbd_suspended(device)) { 1329 /* push back and retry: */ 1330 req->rq_state |= RQ_POSTPONED; 1331 if (req->private_bio) { 1332 bio_put(req->private_bio); 1333 req->private_bio = NULL; 1334 put_ldev(device); 1335 } 1336 goto out; 1337 } 1338 1339 /* We fail READ early, if we can not serve it. 1340 * We must do this before req is registered on any lists. 1341 * Otherwise, drbd_req_complete() will queue failed READ for retry. */ 1342 if (rw != WRITE) { 1343 if (!do_remote_read(req) && !req->private_bio) 1344 goto nodata; 1345 } 1346 1347 /* which transfer log epoch does this belong to? */ 1348 req->epoch = atomic_read(&first_peer_device(device)->connection->current_tle_nr); 1349 1350 /* no point in adding empty flushes to the transfer log, 1351 * they are mapped to drbd barriers already. */ 1352 if (likely(req->i.size!=0)) { 1353 if (rw == WRITE) 1354 first_peer_device(device)->connection->current_tle_writes++; 1355 1356 list_add_tail(&req->tl_requests, &first_peer_device(device)->connection->transfer_log); 1357 } 1358 1359 if (rw == WRITE) { 1360 if (req->private_bio && !may_do_writes(device)) { 1361 bio_put(req->private_bio); 1362 req->private_bio = NULL; 1363 put_ldev(device); 1364 goto nodata; 1365 } 1366 if (!drbd_process_write_request(req)) 1367 no_remote = true; 1368 } else { 1369 /* We either have a private_bio, or we can read from remote. 1370 * Otherwise we had done the goto nodata above. */ 1371 if (req->private_bio == NULL) { 1372 _req_mod(req, TO_BE_SENT); 1373 _req_mod(req, QUEUE_FOR_NET_READ); 1374 } else 1375 no_remote = true; 1376 } 1377 1378 if (no_remote == false) { 1379 struct drbd_plug_cb *plug = drbd_check_plugged(resource); 1380 if (plug) 1381 drbd_update_plug(plug, req); 1382 } 1383 1384 /* If it took the fast path in drbd_request_prepare, add it here. 1385 * The slow path has added it already. */ 1386 if (list_empty(&req->req_pending_master_completion)) 1387 list_add_tail(&req->req_pending_master_completion, 1388 &device->pending_master_completion[rw == WRITE]); 1389 if (req->private_bio) { 1390 /* needs to be marked within the same spinlock */ 1391 req->pre_submit_jif = jiffies; 1392 list_add_tail(&req->req_pending_local, 1393 &device->pending_completion[rw == WRITE]); 1394 _req_mod(req, TO_BE_SUBMITTED); 1395 /* but we need to give up the spinlock to submit */ 1396 submit_private_bio = true; 1397 } else if (no_remote) { 1398 nodata: 1399 if (__ratelimit(&drbd_ratelimit_state)) 1400 drbd_err(device, "IO ERROR: neither local nor remote data, sector %llu+%u\n", 1401 (unsigned long long)req->i.sector, req->i.size >> 9); 1402 /* A write may have been queued for send_oos, however. 1403 * So we can not simply free it, we must go through drbd_req_put_completion_ref() */ 1404 } 1405 1406 out: 1407 drbd_req_put_completion_ref(req, &m, 1); 1408 spin_unlock_irq(&resource->req_lock); 1409 1410 /* Even though above is a kref_put(), this is safe. 1411 * As long as we still need to submit our private bio, 1412 * we hold a completion ref, and the request cannot disappear. 1413 * If however this request did not even have a private bio to submit 1414 * (e.g. remote read), req may already be invalid now. 1415 * That's why we cannot check on req->private_bio. */ 1416 if (submit_private_bio) 1417 drbd_submit_req_private_bio(req); 1418 if (m.bio) 1419 complete_master_bio(device, &m); 1420 } 1421 1422 void __drbd_make_request(struct drbd_device *device, struct bio *bio) 1423 { 1424 struct drbd_request *req = drbd_request_prepare(device, bio); 1425 if (IS_ERR_OR_NULL(req)) 1426 return; 1427 drbd_send_and_submit(device, req); 1428 } 1429 1430 static void submit_fast_path(struct drbd_device *device, struct list_head *incoming) 1431 { 1432 struct blk_plug plug; 1433 struct drbd_request *req, *tmp; 1434 1435 blk_start_plug(&plug); 1436 list_for_each_entry_safe(req, tmp, incoming, tl_requests) { 1437 const int rw = bio_data_dir(req->master_bio); 1438 1439 if (rw == WRITE /* rw != WRITE should not even end up here! */ 1440 && req->private_bio && req->i.size 1441 && !test_bit(AL_SUSPENDED, &device->flags)) { 1442 if (!drbd_al_begin_io_fastpath(device, &req->i)) 1443 continue; 1444 1445 req->rq_state |= RQ_IN_ACT_LOG; 1446 req->in_actlog_jif = jiffies; 1447 atomic_dec(&device->ap_actlog_cnt); 1448 } 1449 1450 list_del_init(&req->tl_requests); 1451 drbd_send_and_submit(device, req); 1452 } 1453 blk_finish_plug(&plug); 1454 } 1455 1456 static bool prepare_al_transaction_nonblock(struct drbd_device *device, 1457 struct list_head *incoming, 1458 struct list_head *pending, 1459 struct list_head *later) 1460 { 1461 struct drbd_request *req; 1462 int wake = 0; 1463 int err; 1464 1465 spin_lock_irq(&device->al_lock); 1466 while ((req = list_first_entry_or_null(incoming, struct drbd_request, tl_requests))) { 1467 err = drbd_al_begin_io_nonblock(device, &req->i); 1468 if (err == -ENOBUFS) 1469 break; 1470 if (err == -EBUSY) 1471 wake = 1; 1472 if (err) 1473 list_move_tail(&req->tl_requests, later); 1474 else 1475 list_move_tail(&req->tl_requests, pending); 1476 } 1477 spin_unlock_irq(&device->al_lock); 1478 if (wake) 1479 wake_up(&device->al_wait); 1480 return !list_empty(pending); 1481 } 1482 1483 static void send_and_submit_pending(struct drbd_device *device, struct list_head *pending) 1484 { 1485 struct blk_plug plug; 1486 struct drbd_request *req; 1487 1488 blk_start_plug(&plug); 1489 while ((req = list_first_entry_or_null(pending, struct drbd_request, tl_requests))) { 1490 req->rq_state |= RQ_IN_ACT_LOG; 1491 req->in_actlog_jif = jiffies; 1492 atomic_dec(&device->ap_actlog_cnt); 1493 list_del_init(&req->tl_requests); 1494 drbd_send_and_submit(device, req); 1495 } 1496 blk_finish_plug(&plug); 1497 } 1498 1499 void do_submit(struct work_struct *ws) 1500 { 1501 struct drbd_device *device = container_of(ws, struct drbd_device, submit.worker); 1502 LIST_HEAD(incoming); /* from drbd_make_request() */ 1503 LIST_HEAD(pending); /* to be submitted after next AL-transaction commit */ 1504 LIST_HEAD(busy); /* blocked by resync requests */ 1505 1506 /* grab new incoming requests */ 1507 spin_lock_irq(&device->resource->req_lock); 1508 list_splice_tail_init(&device->submit.writes, &incoming); 1509 spin_unlock_irq(&device->resource->req_lock); 1510 1511 for (;;) { 1512 DEFINE_WAIT(wait); 1513 1514 /* move used-to-be-busy back to front of incoming */ 1515 list_splice_init(&busy, &incoming); 1516 submit_fast_path(device, &incoming); 1517 if (list_empty(&incoming)) 1518 break; 1519 1520 for (;;) { 1521 prepare_to_wait(&device->al_wait, &wait, TASK_UNINTERRUPTIBLE); 1522 1523 list_splice_init(&busy, &incoming); 1524 prepare_al_transaction_nonblock(device, &incoming, &pending, &busy); 1525 if (!list_empty(&pending)) 1526 break; 1527 1528 schedule(); 1529 1530 /* If all currently "hot" activity log extents are kept busy by 1531 * incoming requests, we still must not totally starve new 1532 * requests to "cold" extents. 1533 * Something left on &incoming means there had not been 1534 * enough update slots available, and the activity log 1535 * has been marked as "starving". 1536 * 1537 * Try again now, without looking for new requests, 1538 * effectively blocking all new requests until we made 1539 * at least _some_ progress with what we currently have. 1540 */ 1541 if (!list_empty(&incoming)) 1542 continue; 1543 1544 /* Nothing moved to pending, but nothing left 1545 * on incoming: all moved to busy! 1546 * Grab new and iterate. */ 1547 spin_lock_irq(&device->resource->req_lock); 1548 list_splice_tail_init(&device->submit.writes, &incoming); 1549 spin_unlock_irq(&device->resource->req_lock); 1550 } 1551 finish_wait(&device->al_wait, &wait); 1552 1553 /* If the transaction was full, before all incoming requests 1554 * had been processed, skip ahead to commit, and iterate 1555 * without splicing in more incoming requests from upper layers. 1556 * 1557 * Else, if all incoming have been processed, 1558 * they have become either "pending" (to be submitted after 1559 * next transaction commit) or "busy" (blocked by resync). 1560 * 1561 * Maybe more was queued, while we prepared the transaction? 1562 * Try to stuff those into this transaction as well. 1563 * Be strictly non-blocking here, 1564 * we already have something to commit. 1565 * 1566 * Commit if we don't make any more progres. 1567 */ 1568 1569 while (list_empty(&incoming)) { 1570 LIST_HEAD(more_pending); 1571 LIST_HEAD(more_incoming); 1572 bool made_progress; 1573 1574 /* It is ok to look outside the lock, 1575 * it's only an optimization anyways */ 1576 if (list_empty(&device->submit.writes)) 1577 break; 1578 1579 spin_lock_irq(&device->resource->req_lock); 1580 list_splice_tail_init(&device->submit.writes, &more_incoming); 1581 spin_unlock_irq(&device->resource->req_lock); 1582 1583 if (list_empty(&more_incoming)) 1584 break; 1585 1586 made_progress = prepare_al_transaction_nonblock(device, &more_incoming, &more_pending, &busy); 1587 1588 list_splice_tail_init(&more_pending, &pending); 1589 list_splice_tail_init(&more_incoming, &incoming); 1590 if (!made_progress) 1591 break; 1592 } 1593 1594 drbd_al_begin_io_commit(device); 1595 send_and_submit_pending(device, &pending); 1596 } 1597 } 1598 1599 blk_qc_t drbd_submit_bio(struct bio *bio) 1600 { 1601 struct drbd_device *device = bio->bi_bdev->bd_disk->private_data; 1602 1603 blk_queue_split(&bio); 1604 1605 /* 1606 * what we "blindly" assume: 1607 */ 1608 D_ASSERT(device, IS_ALIGNED(bio->bi_iter.bi_size, 512)); 1609 1610 inc_ap_bio(device); 1611 __drbd_make_request(device, bio); 1612 return BLK_QC_T_NONE; 1613 } 1614 1615 static bool net_timeout_reached(struct drbd_request *net_req, 1616 struct drbd_connection *connection, 1617 unsigned long now, unsigned long ent, 1618 unsigned int ko_count, unsigned int timeout) 1619 { 1620 struct drbd_device *device = net_req->device; 1621 1622 if (!time_after(now, net_req->pre_send_jif + ent)) 1623 return false; 1624 1625 if (time_in_range(now, connection->last_reconnect_jif, connection->last_reconnect_jif + ent)) 1626 return false; 1627 1628 if (net_req->rq_state & RQ_NET_PENDING) { 1629 drbd_warn(device, "Remote failed to finish a request within %ums > ko-count (%u) * timeout (%u * 0.1s)\n", 1630 jiffies_to_msecs(now - net_req->pre_send_jif), ko_count, timeout); 1631 return true; 1632 } 1633 1634 /* We received an ACK already (or are using protocol A), 1635 * but are waiting for the epoch closing barrier ack. 1636 * Check if we sent the barrier already. We should not blame the peer 1637 * for being unresponsive, if we did not even ask it yet. */ 1638 if (net_req->epoch == connection->send.current_epoch_nr) { 1639 drbd_warn(device, 1640 "We did not send a P_BARRIER for %ums > ko-count (%u) * timeout (%u * 0.1s); drbd kernel thread blocked?\n", 1641 jiffies_to_msecs(now - net_req->pre_send_jif), ko_count, timeout); 1642 return false; 1643 } 1644 1645 /* Worst case: we may have been blocked for whatever reason, then 1646 * suddenly are able to send a lot of requests (and epoch separating 1647 * barriers) in quick succession. 1648 * The timestamp of the net_req may be much too old and not correspond 1649 * to the sending time of the relevant unack'ed barrier packet, so 1650 * would trigger a spurious timeout. The latest barrier packet may 1651 * have a too recent timestamp to trigger the timeout, potentially miss 1652 * a timeout. Right now we don't have a place to conveniently store 1653 * these timestamps. 1654 * But in this particular situation, the application requests are still 1655 * completed to upper layers, DRBD should still "feel" responsive. 1656 * No need yet to kill this connection, it may still recover. 1657 * If not, eventually we will have queued enough into the network for 1658 * us to block. From that point of view, the timestamp of the last sent 1659 * barrier packet is relevant enough. 1660 */ 1661 if (time_after(now, connection->send.last_sent_barrier_jif + ent)) { 1662 drbd_warn(device, "Remote failed to answer a P_BARRIER (sent at %lu jif; now=%lu jif) within %ums > ko-count (%u) * timeout (%u * 0.1s)\n", 1663 connection->send.last_sent_barrier_jif, now, 1664 jiffies_to_msecs(now - connection->send.last_sent_barrier_jif), ko_count, timeout); 1665 return true; 1666 } 1667 return false; 1668 } 1669 1670 /* A request is considered timed out, if 1671 * - we have some effective timeout from the configuration, 1672 * with some state restrictions applied, 1673 * - the oldest request is waiting for a response from the network 1674 * resp. the local disk, 1675 * - the oldest request is in fact older than the effective timeout, 1676 * - the connection was established (resp. disk was attached) 1677 * for longer than the timeout already. 1678 * Note that for 32bit jiffies and very stable connections/disks, 1679 * we may have a wrap around, which is catched by 1680 * !time_in_range(now, last_..._jif, last_..._jif + timeout). 1681 * 1682 * Side effect: once per 32bit wrap-around interval, which means every 1683 * ~198 days with 250 HZ, we have a window where the timeout would need 1684 * to expire twice (worst case) to become effective. Good enough. 1685 */ 1686 1687 void request_timer_fn(struct timer_list *t) 1688 { 1689 struct drbd_device *device = from_timer(device, t, request_timer); 1690 struct drbd_connection *connection = first_peer_device(device)->connection; 1691 struct drbd_request *req_read, *req_write, *req_peer; /* oldest request */ 1692 struct net_conf *nc; 1693 unsigned long oldest_submit_jif; 1694 unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */ 1695 unsigned long now; 1696 unsigned int ko_count = 0, timeout = 0; 1697 1698 rcu_read_lock(); 1699 nc = rcu_dereference(connection->net_conf); 1700 if (nc && device->state.conn >= C_WF_REPORT_PARAMS) { 1701 ko_count = nc->ko_count; 1702 timeout = nc->timeout; 1703 } 1704 1705 if (get_ldev(device)) { /* implicit state.disk >= D_INCONSISTENT */ 1706 dt = rcu_dereference(device->ldev->disk_conf)->disk_timeout * HZ / 10; 1707 put_ldev(device); 1708 } 1709 rcu_read_unlock(); 1710 1711 1712 ent = timeout * HZ/10 * ko_count; 1713 et = min_not_zero(dt, ent); 1714 1715 if (!et) 1716 return; /* Recurring timer stopped */ 1717 1718 now = jiffies; 1719 nt = now + et; 1720 1721 spin_lock_irq(&device->resource->req_lock); 1722 req_read = list_first_entry_or_null(&device->pending_completion[0], struct drbd_request, req_pending_local); 1723 req_write = list_first_entry_or_null(&device->pending_completion[1], struct drbd_request, req_pending_local); 1724 1725 /* maybe the oldest request waiting for the peer is in fact still 1726 * blocking in tcp sendmsg. That's ok, though, that's handled via the 1727 * socket send timeout, requesting a ping, and bumping ko-count in 1728 * we_should_drop_the_connection(). 1729 */ 1730 1731 /* check the oldest request we did successfully sent, 1732 * but which is still waiting for an ACK. */ 1733 req_peer = connection->req_ack_pending; 1734 1735 /* if we don't have such request (e.g. protocoll A) 1736 * check the oldest requests which is still waiting on its epoch 1737 * closing barrier ack. */ 1738 if (!req_peer) 1739 req_peer = connection->req_not_net_done; 1740 1741 /* evaluate the oldest peer request only in one timer! */ 1742 if (req_peer && req_peer->device != device) 1743 req_peer = NULL; 1744 1745 /* do we have something to evaluate? */ 1746 if (req_peer == NULL && req_write == NULL && req_read == NULL) 1747 goto out; 1748 1749 oldest_submit_jif = 1750 (req_write && req_read) 1751 ? ( time_before(req_write->pre_submit_jif, req_read->pre_submit_jif) 1752 ? req_write->pre_submit_jif : req_read->pre_submit_jif ) 1753 : req_write ? req_write->pre_submit_jif 1754 : req_read ? req_read->pre_submit_jif : now; 1755 1756 if (ent && req_peer && net_timeout_reached(req_peer, connection, now, ent, ko_count, timeout)) 1757 _conn_request_state(connection, NS(conn, C_TIMEOUT), CS_VERBOSE | CS_HARD); 1758 1759 if (dt && oldest_submit_jif != now && 1760 time_after(now, oldest_submit_jif + dt) && 1761 !time_in_range(now, device->last_reattach_jif, device->last_reattach_jif + dt)) { 1762 drbd_warn(device, "Local backing device failed to meet the disk-timeout\n"); 1763 __drbd_chk_io_error(device, DRBD_FORCE_DETACH); 1764 } 1765 1766 /* Reschedule timer for the nearest not already expired timeout. 1767 * Fallback to now + min(effective network timeout, disk timeout). */ 1768 ent = (ent && req_peer && time_before(now, req_peer->pre_send_jif + ent)) 1769 ? req_peer->pre_send_jif + ent : now + et; 1770 dt = (dt && oldest_submit_jif != now && time_before(now, oldest_submit_jif + dt)) 1771 ? oldest_submit_jif + dt : now + et; 1772 nt = time_before(ent, dt) ? ent : dt; 1773 out: 1774 spin_unlock_irq(&device->resource->req_lock); 1775 mod_timer(&device->request_timer, nt); 1776 } 1777