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 fallthrough; 757 case WRITE_ACKED_BY_PEER: 758 /* Normal operation protocol C: successfully written on peer. 759 * During resync, even in protocol != C, 760 * we requested an explicit write ack anyways. 761 * Which means we cannot even assert anything here. 762 * Nothing more to do here. 763 * We want to keep the tl in place for all protocols, to cater 764 * for volatile write-back caches on lower level devices. */ 765 goto ack_common; 766 case RECV_ACKED_BY_PEER: 767 D_ASSERT(device, req->rq_state & RQ_EXP_RECEIVE_ACK); 768 /* protocol B; pretends to be successfully written on peer. 769 * see also notes above in HANDED_OVER_TO_NETWORK about 770 * protocol != C */ 771 ack_common: 772 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK); 773 break; 774 775 case POSTPONE_WRITE: 776 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK); 777 /* If this node has already detected the write conflict, the 778 * worker will be waiting on misc_wait. Wake it up once this 779 * request has completed locally. 780 */ 781 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 782 req->rq_state |= RQ_POSTPONED; 783 if (req->i.waiting) 784 wake_up(&device->misc_wait); 785 /* Do not clear RQ_NET_PENDING. This request will make further 786 * progress via restart_conflicting_writes() or 787 * fail_postponed_requests(). Hopefully. */ 788 break; 789 790 case NEG_ACKED: 791 mod_rq_state(req, m, RQ_NET_OK|RQ_NET_PENDING, 0); 792 break; 793 794 case FAIL_FROZEN_DISK_IO: 795 if (!(req->rq_state & RQ_LOCAL_COMPLETED)) 796 break; 797 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0); 798 break; 799 800 case RESTART_FROZEN_DISK_IO: 801 if (!(req->rq_state & RQ_LOCAL_COMPLETED)) 802 break; 803 804 mod_rq_state(req, m, 805 RQ_COMPLETION_SUSP|RQ_LOCAL_COMPLETED, 806 RQ_LOCAL_PENDING); 807 808 rv = MR_READ; 809 if (bio_data_dir(req->master_bio) == WRITE) 810 rv = MR_WRITE; 811 812 get_ldev(device); /* always succeeds in this call path */ 813 req->w.cb = w_restart_disk_io; 814 drbd_queue_work(&connection->sender_work, 815 &req->w); 816 break; 817 818 case RESEND: 819 /* Simply complete (local only) READs. */ 820 if (!(req->rq_state & RQ_WRITE) && !req->w.cb) { 821 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0); 822 break; 823 } 824 825 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK 826 before the connection loss (B&C only); only P_BARRIER_ACK 827 (or the local completion?) was missing when we suspended. 828 Throwing them out of the TL here by pretending we got a BARRIER_ACK. 829 During connection handshake, we ensure that the peer was not rebooted. */ 830 if (!(req->rq_state & RQ_NET_OK)) { 831 /* FIXME could this possibly be a req->dw.cb == w_send_out_of_sync? 832 * in that case we must not set RQ_NET_PENDING. */ 833 834 mod_rq_state(req, m, RQ_COMPLETION_SUSP, RQ_NET_QUEUED|RQ_NET_PENDING); 835 if (req->w.cb) { 836 /* w.cb expected to be w_send_dblock, or w_send_read_req */ 837 drbd_queue_work(&connection->sender_work, 838 &req->w); 839 rv = req->rq_state & RQ_WRITE ? MR_WRITE : MR_READ; 840 } /* else: FIXME can this happen? */ 841 break; 842 } 843 fallthrough; /* to BARRIER_ACKED */ 844 845 case BARRIER_ACKED: 846 /* barrier ack for READ requests does not make sense */ 847 if (!(req->rq_state & RQ_WRITE)) 848 break; 849 850 if (req->rq_state & RQ_NET_PENDING) { 851 /* barrier came in before all requests were acked. 852 * this is bad, because if the connection is lost now, 853 * we won't be able to clean them up... */ 854 drbd_err(device, "FIXME (BARRIER_ACKED but pending)\n"); 855 } 856 /* Allowed to complete requests, even while suspended. 857 * As this is called for all requests within a matching epoch, 858 * we need to filter, and only set RQ_NET_DONE for those that 859 * have actually been on the wire. */ 860 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 861 (req->rq_state & RQ_NET_MASK) ? RQ_NET_DONE : 0); 862 break; 863 864 case DATA_RECEIVED: 865 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 866 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE); 867 break; 868 869 case QUEUE_AS_DRBD_BARRIER: 870 start_new_tl_epoch(connection); 871 mod_rq_state(req, m, 0, RQ_NET_OK|RQ_NET_DONE); 872 break; 873 } 874 875 return rv; 876 } 877 878 /* we may do a local read if: 879 * - we are consistent (of course), 880 * - or we are generally inconsistent, 881 * BUT we are still/already IN SYNC for this area. 882 * since size may be bigger than BM_BLOCK_SIZE, 883 * we may need to check several bits. 884 */ 885 static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size) 886 { 887 unsigned long sbnr, ebnr; 888 sector_t esector, nr_sectors; 889 890 if (device->state.disk == D_UP_TO_DATE) 891 return true; 892 if (device->state.disk != D_INCONSISTENT) 893 return false; 894 esector = sector + (size >> 9) - 1; 895 nr_sectors = get_capacity(device->vdisk); 896 D_ASSERT(device, sector < nr_sectors); 897 D_ASSERT(device, esector < nr_sectors); 898 899 sbnr = BM_SECT_TO_BIT(sector); 900 ebnr = BM_SECT_TO_BIT(esector); 901 902 return drbd_bm_count_bits(device, sbnr, ebnr) == 0; 903 } 904 905 static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t sector, 906 enum drbd_read_balancing rbm) 907 { 908 struct backing_dev_info *bdi; 909 int stripe_shift; 910 911 switch (rbm) { 912 case RB_CONGESTED_REMOTE: 913 bdi = device->ldev->backing_bdev->bd_disk->queue->backing_dev_info; 914 return bdi_read_congested(bdi); 915 case RB_LEAST_PENDING: 916 return atomic_read(&device->local_cnt) > 917 atomic_read(&device->ap_pending_cnt) + atomic_read(&device->rs_pending_cnt); 918 case RB_32K_STRIPING: /* stripe_shift = 15 */ 919 case RB_64K_STRIPING: 920 case RB_128K_STRIPING: 921 case RB_256K_STRIPING: 922 case RB_512K_STRIPING: 923 case RB_1M_STRIPING: /* stripe_shift = 20 */ 924 stripe_shift = (rbm - RB_32K_STRIPING + 15); 925 return (sector >> (stripe_shift - 9)) & 1; 926 case RB_ROUND_ROBIN: 927 return test_and_change_bit(READ_BALANCE_RR, &device->flags); 928 case RB_PREFER_REMOTE: 929 return true; 930 case RB_PREFER_LOCAL: 931 default: 932 return false; 933 } 934 } 935 936 /* 937 * complete_conflicting_writes - wait for any conflicting write requests 938 * 939 * The write_requests tree contains all active write requests which we 940 * currently know about. Wait for any requests to complete which conflict with 941 * the new one. 942 * 943 * Only way out: remove the conflicting intervals from the tree. 944 */ 945 static void complete_conflicting_writes(struct drbd_request *req) 946 { 947 DEFINE_WAIT(wait); 948 struct drbd_device *device = req->device; 949 struct drbd_interval *i; 950 sector_t sector = req->i.sector; 951 int size = req->i.size; 952 953 for (;;) { 954 drbd_for_each_overlap(i, &device->write_requests, sector, size) { 955 /* Ignore, if already completed to upper layers. */ 956 if (i->completed) 957 continue; 958 /* Handle the first found overlap. After the schedule 959 * we have to restart the tree walk. */ 960 break; 961 } 962 if (!i) /* if any */ 963 break; 964 965 /* Indicate to wake up device->misc_wait on progress. */ 966 prepare_to_wait(&device->misc_wait, &wait, TASK_UNINTERRUPTIBLE); 967 i->waiting = true; 968 spin_unlock_irq(&device->resource->req_lock); 969 schedule(); 970 spin_lock_irq(&device->resource->req_lock); 971 } 972 finish_wait(&device->misc_wait, &wait); 973 } 974 975 /* called within req_lock */ 976 static void maybe_pull_ahead(struct drbd_device *device) 977 { 978 struct drbd_connection *connection = first_peer_device(device)->connection; 979 struct net_conf *nc; 980 bool congested = false; 981 enum drbd_on_congestion on_congestion; 982 983 rcu_read_lock(); 984 nc = rcu_dereference(connection->net_conf); 985 on_congestion = nc ? nc->on_congestion : OC_BLOCK; 986 rcu_read_unlock(); 987 if (on_congestion == OC_BLOCK || 988 connection->agreed_pro_version < 96) 989 return; 990 991 if (on_congestion == OC_PULL_AHEAD && device->state.conn == C_AHEAD) 992 return; /* nothing to do ... */ 993 994 /* If I don't even have good local storage, we can not reasonably try 995 * to pull ahead of the peer. We also need the local reference to make 996 * sure device->act_log is there. 997 */ 998 if (!get_ldev_if_state(device, D_UP_TO_DATE)) 999 return; 1000 1001 if (nc->cong_fill && 1002 atomic_read(&device->ap_in_flight) >= nc->cong_fill) { 1003 drbd_info(device, "Congestion-fill threshold reached\n"); 1004 congested = true; 1005 } 1006 1007 if (device->act_log->used >= nc->cong_extents) { 1008 drbd_info(device, "Congestion-extents threshold reached\n"); 1009 congested = true; 1010 } 1011 1012 if (congested) { 1013 /* start a new epoch for non-mirrored writes */ 1014 start_new_tl_epoch(first_peer_device(device)->connection); 1015 1016 if (on_congestion == OC_PULL_AHEAD) 1017 _drbd_set_state(_NS(device, conn, C_AHEAD), 0, NULL); 1018 else /*nc->on_congestion == OC_DISCONNECT */ 1019 _drbd_set_state(_NS(device, conn, C_DISCONNECTING), 0, NULL); 1020 } 1021 put_ldev(device); 1022 } 1023 1024 /* If this returns false, and req->private_bio is still set, 1025 * this should be submitted locally. 1026 * 1027 * If it returns false, but req->private_bio is not set, 1028 * we do not have access to good data :( 1029 * 1030 * Otherwise, this destroys req->private_bio, if any, 1031 * and returns true. 1032 */ 1033 static bool do_remote_read(struct drbd_request *req) 1034 { 1035 struct drbd_device *device = req->device; 1036 enum drbd_read_balancing rbm; 1037 1038 if (req->private_bio) { 1039 if (!drbd_may_do_local_read(device, 1040 req->i.sector, req->i.size)) { 1041 bio_put(req->private_bio); 1042 req->private_bio = NULL; 1043 put_ldev(device); 1044 } 1045 } 1046 1047 if (device->state.pdsk != D_UP_TO_DATE) 1048 return false; 1049 1050 if (req->private_bio == NULL) 1051 return true; 1052 1053 /* TODO: improve read balancing decisions, take into account drbd 1054 * protocol, pending requests etc. */ 1055 1056 rcu_read_lock(); 1057 rbm = rcu_dereference(device->ldev->disk_conf)->read_balancing; 1058 rcu_read_unlock(); 1059 1060 if (rbm == RB_PREFER_LOCAL && req->private_bio) 1061 return false; /* submit locally */ 1062 1063 if (remote_due_to_read_balancing(device, req->i.sector, rbm)) { 1064 if (req->private_bio) { 1065 bio_put(req->private_bio); 1066 req->private_bio = NULL; 1067 put_ldev(device); 1068 } 1069 return true; 1070 } 1071 1072 return false; 1073 } 1074 1075 bool drbd_should_do_remote(union drbd_dev_state s) 1076 { 1077 return s.pdsk == D_UP_TO_DATE || 1078 (s.pdsk >= D_INCONSISTENT && 1079 s.conn >= C_WF_BITMAP_T && 1080 s.conn < C_AHEAD); 1081 /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T. 1082 That is equivalent since before 96 IO was frozen in the C_WF_BITMAP* 1083 states. */ 1084 } 1085 1086 static bool drbd_should_send_out_of_sync(union drbd_dev_state s) 1087 { 1088 return s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S; 1089 /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary 1090 since we enter state C_AHEAD only if proto >= 96 */ 1091 } 1092 1093 /* returns number of connections (== 1, for drbd 8.4) 1094 * expected to actually write this data, 1095 * which does NOT include those that we are L_AHEAD for. */ 1096 static int drbd_process_write_request(struct drbd_request *req) 1097 { 1098 struct drbd_device *device = req->device; 1099 int remote, send_oos; 1100 1101 remote = drbd_should_do_remote(device->state); 1102 send_oos = drbd_should_send_out_of_sync(device->state); 1103 1104 /* Need to replicate writes. Unless it is an empty flush, 1105 * which is better mapped to a DRBD P_BARRIER packet, 1106 * also for drbd wire protocol compatibility reasons. 1107 * If this was a flush, just start a new epoch. 1108 * Unless the current epoch was empty anyways, or we are not currently 1109 * replicating, in which case there is no point. */ 1110 if (unlikely(req->i.size == 0)) { 1111 /* The only size==0 bios we expect are empty flushes. */ 1112 D_ASSERT(device, req->master_bio->bi_opf & REQ_PREFLUSH); 1113 if (remote) 1114 _req_mod(req, QUEUE_AS_DRBD_BARRIER); 1115 return remote; 1116 } 1117 1118 if (!remote && !send_oos) 1119 return 0; 1120 1121 D_ASSERT(device, !(remote && send_oos)); 1122 1123 if (remote) { 1124 _req_mod(req, TO_BE_SENT); 1125 _req_mod(req, QUEUE_FOR_NET_WRITE); 1126 } else if (drbd_set_out_of_sync(device, req->i.sector, req->i.size)) 1127 _req_mod(req, QUEUE_FOR_SEND_OOS); 1128 1129 return remote; 1130 } 1131 1132 static void drbd_process_discard_or_zeroes_req(struct drbd_request *req, int flags) 1133 { 1134 int err = drbd_issue_discard_or_zero_out(req->device, 1135 req->i.sector, req->i.size >> 9, flags); 1136 if (err) 1137 req->private_bio->bi_status = BLK_STS_IOERR; 1138 bio_endio(req->private_bio); 1139 } 1140 1141 static void 1142 drbd_submit_req_private_bio(struct drbd_request *req) 1143 { 1144 struct drbd_device *device = req->device; 1145 struct bio *bio = req->private_bio; 1146 unsigned int type; 1147 1148 if (bio_op(bio) != REQ_OP_READ) 1149 type = DRBD_FAULT_DT_WR; 1150 else if (bio->bi_opf & REQ_RAHEAD) 1151 type = DRBD_FAULT_DT_RA; 1152 else 1153 type = DRBD_FAULT_DT_RD; 1154 1155 bio_set_dev(bio, device->ldev->backing_bdev); 1156 1157 /* State may have changed since we grabbed our reference on the 1158 * ->ldev member. Double check, and short-circuit to endio. 1159 * In case the last activity log transaction failed to get on 1160 * stable storage, and this is a WRITE, we may not even submit 1161 * this bio. */ 1162 if (get_ldev(device)) { 1163 if (drbd_insert_fault(device, type)) 1164 bio_io_error(bio); 1165 else if (bio_op(bio) == REQ_OP_WRITE_ZEROES) 1166 drbd_process_discard_or_zeroes_req(req, EE_ZEROOUT | 1167 ((bio->bi_opf & REQ_NOUNMAP) ? 0 : EE_TRIM)); 1168 else if (bio_op(bio) == REQ_OP_DISCARD) 1169 drbd_process_discard_or_zeroes_req(req, EE_TRIM); 1170 else 1171 submit_bio_noacct(bio); 1172 put_ldev(device); 1173 } else 1174 bio_io_error(bio); 1175 } 1176 1177 static void drbd_queue_write(struct drbd_device *device, struct drbd_request *req) 1178 { 1179 spin_lock_irq(&device->resource->req_lock); 1180 list_add_tail(&req->tl_requests, &device->submit.writes); 1181 list_add_tail(&req->req_pending_master_completion, 1182 &device->pending_master_completion[1 /* WRITE */]); 1183 spin_unlock_irq(&device->resource->req_lock); 1184 queue_work(device->submit.wq, &device->submit.worker); 1185 /* do_submit() may sleep internally on al_wait, too */ 1186 wake_up(&device->al_wait); 1187 } 1188 1189 /* returns the new drbd_request pointer, if the caller is expected to 1190 * drbd_send_and_submit() it (to save latency), or NULL if we queued the 1191 * request on the submitter thread. 1192 * Returns ERR_PTR(-ENOMEM) if we cannot allocate a drbd_request. 1193 */ 1194 static struct drbd_request * 1195 drbd_request_prepare(struct drbd_device *device, struct bio *bio) 1196 { 1197 const int rw = bio_data_dir(bio); 1198 struct drbd_request *req; 1199 1200 /* allocate outside of all locks; */ 1201 req = drbd_req_new(device, bio); 1202 if (!req) { 1203 dec_ap_bio(device); 1204 /* only pass the error to the upper layers. 1205 * if user cannot handle io errors, that's not our business. */ 1206 drbd_err(device, "could not kmalloc() req\n"); 1207 bio->bi_status = BLK_STS_RESOURCE; 1208 bio_endio(bio); 1209 return ERR_PTR(-ENOMEM); 1210 } 1211 1212 /* Update disk stats */ 1213 req->start_jif = bio_start_io_acct(req->master_bio); 1214 1215 if (!get_ldev(device)) { 1216 bio_put(req->private_bio); 1217 req->private_bio = NULL; 1218 } 1219 1220 /* process discards always from our submitter thread */ 1221 if (bio_op(bio) == REQ_OP_WRITE_ZEROES || 1222 bio_op(bio) == REQ_OP_DISCARD) 1223 goto queue_for_submitter_thread; 1224 1225 if (rw == WRITE && req->private_bio && req->i.size 1226 && !test_bit(AL_SUSPENDED, &device->flags)) { 1227 if (!drbd_al_begin_io_fastpath(device, &req->i)) 1228 goto queue_for_submitter_thread; 1229 req->rq_state |= RQ_IN_ACT_LOG; 1230 req->in_actlog_jif = jiffies; 1231 } 1232 return req; 1233 1234 queue_for_submitter_thread: 1235 atomic_inc(&device->ap_actlog_cnt); 1236 drbd_queue_write(device, req); 1237 return NULL; 1238 } 1239 1240 /* Require at least one path to current data. 1241 * We don't want to allow writes on C_STANDALONE D_INCONSISTENT: 1242 * We would not allow to read what was written, 1243 * we would not have bumped the data generation uuids, 1244 * we would cause data divergence for all the wrong reasons. 1245 * 1246 * If we don't see at least one D_UP_TO_DATE, we will fail this request, 1247 * which either returns EIO, or, if OND_SUSPEND_IO is set, suspends IO, 1248 * and queues for retry later. 1249 */ 1250 static bool may_do_writes(struct drbd_device *device) 1251 { 1252 const union drbd_dev_state s = device->state; 1253 return s.disk == D_UP_TO_DATE || s.pdsk == D_UP_TO_DATE; 1254 } 1255 1256 struct drbd_plug_cb { 1257 struct blk_plug_cb cb; 1258 struct drbd_request *most_recent_req; 1259 /* do we need more? */ 1260 }; 1261 1262 static void drbd_unplug(struct blk_plug_cb *cb, bool from_schedule) 1263 { 1264 struct drbd_plug_cb *plug = container_of(cb, struct drbd_plug_cb, cb); 1265 struct drbd_resource *resource = plug->cb.data; 1266 struct drbd_request *req = plug->most_recent_req; 1267 1268 kfree(cb); 1269 if (!req) 1270 return; 1271 1272 spin_lock_irq(&resource->req_lock); 1273 /* In case the sender did not process it yet, raise the flag to 1274 * have it followed with P_UNPLUG_REMOTE just after. */ 1275 req->rq_state |= RQ_UNPLUG; 1276 /* but also queue a generic unplug */ 1277 drbd_queue_unplug(req->device); 1278 kref_put(&req->kref, drbd_req_destroy); 1279 spin_unlock_irq(&resource->req_lock); 1280 } 1281 1282 static struct drbd_plug_cb* drbd_check_plugged(struct drbd_resource *resource) 1283 { 1284 /* A lot of text to say 1285 * return (struct drbd_plug_cb*)blk_check_plugged(); */ 1286 struct drbd_plug_cb *plug; 1287 struct blk_plug_cb *cb = blk_check_plugged(drbd_unplug, resource, sizeof(*plug)); 1288 1289 if (cb) 1290 plug = container_of(cb, struct drbd_plug_cb, cb); 1291 else 1292 plug = NULL; 1293 return plug; 1294 } 1295 1296 static void drbd_update_plug(struct drbd_plug_cb *plug, struct drbd_request *req) 1297 { 1298 struct drbd_request *tmp = plug->most_recent_req; 1299 /* Will be sent to some peer. 1300 * Remember to tag it with UNPLUG_REMOTE on unplug */ 1301 kref_get(&req->kref); 1302 plug->most_recent_req = req; 1303 if (tmp) 1304 kref_put(&tmp->kref, drbd_req_destroy); 1305 } 1306 1307 static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request *req) 1308 { 1309 struct drbd_resource *resource = device->resource; 1310 const int rw = bio_data_dir(req->master_bio); 1311 struct bio_and_error m = { NULL, }; 1312 bool no_remote = false; 1313 bool submit_private_bio = false; 1314 1315 spin_lock_irq(&resource->req_lock); 1316 if (rw == WRITE) { 1317 /* This may temporarily give up the req_lock, 1318 * but will re-aquire it before it returns here. 1319 * Needs to be before the check on drbd_suspended() */ 1320 complete_conflicting_writes(req); 1321 /* no more giving up req_lock from now on! */ 1322 1323 /* check for congestion, and potentially stop sending 1324 * full data updates, but start sending "dirty bits" only. */ 1325 maybe_pull_ahead(device); 1326 } 1327 1328 1329 if (drbd_suspended(device)) { 1330 /* push back and retry: */ 1331 req->rq_state |= RQ_POSTPONED; 1332 if (req->private_bio) { 1333 bio_put(req->private_bio); 1334 req->private_bio = NULL; 1335 put_ldev(device); 1336 } 1337 goto out; 1338 } 1339 1340 /* We fail READ early, if we can not serve it. 1341 * We must do this before req is registered on any lists. 1342 * Otherwise, drbd_req_complete() will queue failed READ for retry. */ 1343 if (rw != WRITE) { 1344 if (!do_remote_read(req) && !req->private_bio) 1345 goto nodata; 1346 } 1347 1348 /* which transfer log epoch does this belong to? */ 1349 req->epoch = atomic_read(&first_peer_device(device)->connection->current_tle_nr); 1350 1351 /* no point in adding empty flushes to the transfer log, 1352 * they are mapped to drbd barriers already. */ 1353 if (likely(req->i.size!=0)) { 1354 if (rw == WRITE) 1355 first_peer_device(device)->connection->current_tle_writes++; 1356 1357 list_add_tail(&req->tl_requests, &first_peer_device(device)->connection->transfer_log); 1358 } 1359 1360 if (rw == WRITE) { 1361 if (req->private_bio && !may_do_writes(device)) { 1362 bio_put(req->private_bio); 1363 req->private_bio = NULL; 1364 put_ldev(device); 1365 goto nodata; 1366 } 1367 if (!drbd_process_write_request(req)) 1368 no_remote = true; 1369 } else { 1370 /* We either have a private_bio, or we can read from remote. 1371 * Otherwise we had done the goto nodata above. */ 1372 if (req->private_bio == NULL) { 1373 _req_mod(req, TO_BE_SENT); 1374 _req_mod(req, QUEUE_FOR_NET_READ); 1375 } else 1376 no_remote = true; 1377 } 1378 1379 if (no_remote == false) { 1380 struct drbd_plug_cb *plug = drbd_check_plugged(resource); 1381 if (plug) 1382 drbd_update_plug(plug, req); 1383 } 1384 1385 /* If it took the fast path in drbd_request_prepare, add it here. 1386 * The slow path has added it already. */ 1387 if (list_empty(&req->req_pending_master_completion)) 1388 list_add_tail(&req->req_pending_master_completion, 1389 &device->pending_master_completion[rw == WRITE]); 1390 if (req->private_bio) { 1391 /* needs to be marked within the same spinlock */ 1392 req->pre_submit_jif = jiffies; 1393 list_add_tail(&req->req_pending_local, 1394 &device->pending_completion[rw == WRITE]); 1395 _req_mod(req, TO_BE_SUBMITTED); 1396 /* but we need to give up the spinlock to submit */ 1397 submit_private_bio = true; 1398 } else if (no_remote) { 1399 nodata: 1400 if (__ratelimit(&drbd_ratelimit_state)) 1401 drbd_err(device, "IO ERROR: neither local nor remote data, sector %llu+%u\n", 1402 (unsigned long long)req->i.sector, req->i.size >> 9); 1403 /* A write may have been queued for send_oos, however. 1404 * So we can not simply free it, we must go through drbd_req_put_completion_ref() */ 1405 } 1406 1407 out: 1408 drbd_req_put_completion_ref(req, &m, 1); 1409 spin_unlock_irq(&resource->req_lock); 1410 1411 /* Even though above is a kref_put(), this is safe. 1412 * As long as we still need to submit our private bio, 1413 * we hold a completion ref, and the request cannot disappear. 1414 * If however this request did not even have a private bio to submit 1415 * (e.g. remote read), req may already be invalid now. 1416 * That's why we cannot check on req->private_bio. */ 1417 if (submit_private_bio) 1418 drbd_submit_req_private_bio(req); 1419 if (m.bio) 1420 complete_master_bio(device, &m); 1421 } 1422 1423 void __drbd_make_request(struct drbd_device *device, struct bio *bio) 1424 { 1425 struct drbd_request *req = drbd_request_prepare(device, bio); 1426 if (IS_ERR_OR_NULL(req)) 1427 return; 1428 drbd_send_and_submit(device, req); 1429 } 1430 1431 static void submit_fast_path(struct drbd_device *device, struct list_head *incoming) 1432 { 1433 struct blk_plug plug; 1434 struct drbd_request *req, *tmp; 1435 1436 blk_start_plug(&plug); 1437 list_for_each_entry_safe(req, tmp, incoming, tl_requests) { 1438 const int rw = bio_data_dir(req->master_bio); 1439 1440 if (rw == WRITE /* rw != WRITE should not even end up here! */ 1441 && req->private_bio && req->i.size 1442 && !test_bit(AL_SUSPENDED, &device->flags)) { 1443 if (!drbd_al_begin_io_fastpath(device, &req->i)) 1444 continue; 1445 1446 req->rq_state |= RQ_IN_ACT_LOG; 1447 req->in_actlog_jif = jiffies; 1448 atomic_dec(&device->ap_actlog_cnt); 1449 } 1450 1451 list_del_init(&req->tl_requests); 1452 drbd_send_and_submit(device, req); 1453 } 1454 blk_finish_plug(&plug); 1455 } 1456 1457 static bool prepare_al_transaction_nonblock(struct drbd_device *device, 1458 struct list_head *incoming, 1459 struct list_head *pending, 1460 struct list_head *later) 1461 { 1462 struct drbd_request *req; 1463 int wake = 0; 1464 int err; 1465 1466 spin_lock_irq(&device->al_lock); 1467 while ((req = list_first_entry_or_null(incoming, struct drbd_request, tl_requests))) { 1468 err = drbd_al_begin_io_nonblock(device, &req->i); 1469 if (err == -ENOBUFS) 1470 break; 1471 if (err == -EBUSY) 1472 wake = 1; 1473 if (err) 1474 list_move_tail(&req->tl_requests, later); 1475 else 1476 list_move_tail(&req->tl_requests, pending); 1477 } 1478 spin_unlock_irq(&device->al_lock); 1479 if (wake) 1480 wake_up(&device->al_wait); 1481 return !list_empty(pending); 1482 } 1483 1484 static void send_and_submit_pending(struct drbd_device *device, struct list_head *pending) 1485 { 1486 struct blk_plug plug; 1487 struct drbd_request *req; 1488 1489 blk_start_plug(&plug); 1490 while ((req = list_first_entry_or_null(pending, struct drbd_request, tl_requests))) { 1491 req->rq_state |= RQ_IN_ACT_LOG; 1492 req->in_actlog_jif = jiffies; 1493 atomic_dec(&device->ap_actlog_cnt); 1494 list_del_init(&req->tl_requests); 1495 drbd_send_and_submit(device, req); 1496 } 1497 blk_finish_plug(&plug); 1498 } 1499 1500 void do_submit(struct work_struct *ws) 1501 { 1502 struct drbd_device *device = container_of(ws, struct drbd_device, submit.worker); 1503 LIST_HEAD(incoming); /* from drbd_make_request() */ 1504 LIST_HEAD(pending); /* to be submitted after next AL-transaction commit */ 1505 LIST_HEAD(busy); /* blocked by resync requests */ 1506 1507 /* grab new incoming requests */ 1508 spin_lock_irq(&device->resource->req_lock); 1509 list_splice_tail_init(&device->submit.writes, &incoming); 1510 spin_unlock_irq(&device->resource->req_lock); 1511 1512 for (;;) { 1513 DEFINE_WAIT(wait); 1514 1515 /* move used-to-be-busy back to front of incoming */ 1516 list_splice_init(&busy, &incoming); 1517 submit_fast_path(device, &incoming); 1518 if (list_empty(&incoming)) 1519 break; 1520 1521 for (;;) { 1522 prepare_to_wait(&device->al_wait, &wait, TASK_UNINTERRUPTIBLE); 1523 1524 list_splice_init(&busy, &incoming); 1525 prepare_al_transaction_nonblock(device, &incoming, &pending, &busy); 1526 if (!list_empty(&pending)) 1527 break; 1528 1529 schedule(); 1530 1531 /* If all currently "hot" activity log extents are kept busy by 1532 * incoming requests, we still must not totally starve new 1533 * requests to "cold" extents. 1534 * Something left on &incoming means there had not been 1535 * enough update slots available, and the activity log 1536 * has been marked as "starving". 1537 * 1538 * Try again now, without looking for new requests, 1539 * effectively blocking all new requests until we made 1540 * at least _some_ progress with what we currently have. 1541 */ 1542 if (!list_empty(&incoming)) 1543 continue; 1544 1545 /* Nothing moved to pending, but nothing left 1546 * on incoming: all moved to busy! 1547 * Grab new and iterate. */ 1548 spin_lock_irq(&device->resource->req_lock); 1549 list_splice_tail_init(&device->submit.writes, &incoming); 1550 spin_unlock_irq(&device->resource->req_lock); 1551 } 1552 finish_wait(&device->al_wait, &wait); 1553 1554 /* If the transaction was full, before all incoming requests 1555 * had been processed, skip ahead to commit, and iterate 1556 * without splicing in more incoming requests from upper layers. 1557 * 1558 * Else, if all incoming have been processed, 1559 * they have become either "pending" (to be submitted after 1560 * next transaction commit) or "busy" (blocked by resync). 1561 * 1562 * Maybe more was queued, while we prepared the transaction? 1563 * Try to stuff those into this transaction as well. 1564 * Be strictly non-blocking here, 1565 * we already have something to commit. 1566 * 1567 * Commit if we don't make any more progres. 1568 */ 1569 1570 while (list_empty(&incoming)) { 1571 LIST_HEAD(more_pending); 1572 LIST_HEAD(more_incoming); 1573 bool made_progress; 1574 1575 /* It is ok to look outside the lock, 1576 * it's only an optimization anyways */ 1577 if (list_empty(&device->submit.writes)) 1578 break; 1579 1580 spin_lock_irq(&device->resource->req_lock); 1581 list_splice_tail_init(&device->submit.writes, &more_incoming); 1582 spin_unlock_irq(&device->resource->req_lock); 1583 1584 if (list_empty(&more_incoming)) 1585 break; 1586 1587 made_progress = prepare_al_transaction_nonblock(device, &more_incoming, &more_pending, &busy); 1588 1589 list_splice_tail_init(&more_pending, &pending); 1590 list_splice_tail_init(&more_incoming, &incoming); 1591 if (!made_progress) 1592 break; 1593 } 1594 1595 drbd_al_begin_io_commit(device); 1596 send_and_submit_pending(device, &pending); 1597 } 1598 } 1599 1600 blk_qc_t drbd_submit_bio(struct bio *bio) 1601 { 1602 struct drbd_device *device = bio->bi_bdev->bd_disk->private_data; 1603 1604 blk_queue_split(&bio); 1605 1606 /* 1607 * what we "blindly" assume: 1608 */ 1609 D_ASSERT(device, IS_ALIGNED(bio->bi_iter.bi_size, 512)); 1610 1611 inc_ap_bio(device); 1612 __drbd_make_request(device, bio); 1613 return BLK_QC_T_NONE; 1614 } 1615 1616 static bool net_timeout_reached(struct drbd_request *net_req, 1617 struct drbd_connection *connection, 1618 unsigned long now, unsigned long ent, 1619 unsigned int ko_count, unsigned int timeout) 1620 { 1621 struct drbd_device *device = net_req->device; 1622 1623 if (!time_after(now, net_req->pre_send_jif + ent)) 1624 return false; 1625 1626 if (time_in_range(now, connection->last_reconnect_jif, connection->last_reconnect_jif + ent)) 1627 return false; 1628 1629 if (net_req->rq_state & RQ_NET_PENDING) { 1630 drbd_warn(device, "Remote failed to finish a request within %ums > ko-count (%u) * timeout (%u * 0.1s)\n", 1631 jiffies_to_msecs(now - net_req->pre_send_jif), ko_count, timeout); 1632 return true; 1633 } 1634 1635 /* We received an ACK already (or are using protocol A), 1636 * but are waiting for the epoch closing barrier ack. 1637 * Check if we sent the barrier already. We should not blame the peer 1638 * for being unresponsive, if we did not even ask it yet. */ 1639 if (net_req->epoch == connection->send.current_epoch_nr) { 1640 drbd_warn(device, 1641 "We did not send a P_BARRIER for %ums > ko-count (%u) * timeout (%u * 0.1s); drbd kernel thread blocked?\n", 1642 jiffies_to_msecs(now - net_req->pre_send_jif), ko_count, timeout); 1643 return false; 1644 } 1645 1646 /* Worst case: we may have been blocked for whatever reason, then 1647 * suddenly are able to send a lot of requests (and epoch separating 1648 * barriers) in quick succession. 1649 * The timestamp of the net_req may be much too old and not correspond 1650 * to the sending time of the relevant unack'ed barrier packet, so 1651 * would trigger a spurious timeout. The latest barrier packet may 1652 * have a too recent timestamp to trigger the timeout, potentially miss 1653 * a timeout. Right now we don't have a place to conveniently store 1654 * these timestamps. 1655 * But in this particular situation, the application requests are still 1656 * completed to upper layers, DRBD should still "feel" responsive. 1657 * No need yet to kill this connection, it may still recover. 1658 * If not, eventually we will have queued enough into the network for 1659 * us to block. From that point of view, the timestamp of the last sent 1660 * barrier packet is relevant enough. 1661 */ 1662 if (time_after(now, connection->send.last_sent_barrier_jif + ent)) { 1663 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", 1664 connection->send.last_sent_barrier_jif, now, 1665 jiffies_to_msecs(now - connection->send.last_sent_barrier_jif), ko_count, timeout); 1666 return true; 1667 } 1668 return false; 1669 } 1670 1671 /* A request is considered timed out, if 1672 * - we have some effective timeout from the configuration, 1673 * with some state restrictions applied, 1674 * - the oldest request is waiting for a response from the network 1675 * resp. the local disk, 1676 * - the oldest request is in fact older than the effective timeout, 1677 * - the connection was established (resp. disk was attached) 1678 * for longer than the timeout already. 1679 * Note that for 32bit jiffies and very stable connections/disks, 1680 * we may have a wrap around, which is catched by 1681 * !time_in_range(now, last_..._jif, last_..._jif + timeout). 1682 * 1683 * Side effect: once per 32bit wrap-around interval, which means every 1684 * ~198 days with 250 HZ, we have a window where the timeout would need 1685 * to expire twice (worst case) to become effective. Good enough. 1686 */ 1687 1688 void request_timer_fn(struct timer_list *t) 1689 { 1690 struct drbd_device *device = from_timer(device, t, request_timer); 1691 struct drbd_connection *connection = first_peer_device(device)->connection; 1692 struct drbd_request *req_read, *req_write, *req_peer; /* oldest request */ 1693 struct net_conf *nc; 1694 unsigned long oldest_submit_jif; 1695 unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */ 1696 unsigned long now; 1697 unsigned int ko_count = 0, timeout = 0; 1698 1699 rcu_read_lock(); 1700 nc = rcu_dereference(connection->net_conf); 1701 if (nc && device->state.conn >= C_WF_REPORT_PARAMS) { 1702 ko_count = nc->ko_count; 1703 timeout = nc->timeout; 1704 } 1705 1706 if (get_ldev(device)) { /* implicit state.disk >= D_INCONSISTENT */ 1707 dt = rcu_dereference(device->ldev->disk_conf)->disk_timeout * HZ / 10; 1708 put_ldev(device); 1709 } 1710 rcu_read_unlock(); 1711 1712 1713 ent = timeout * HZ/10 * ko_count; 1714 et = min_not_zero(dt, ent); 1715 1716 if (!et) 1717 return; /* Recurring timer stopped */ 1718 1719 now = jiffies; 1720 nt = now + et; 1721 1722 spin_lock_irq(&device->resource->req_lock); 1723 req_read = list_first_entry_or_null(&device->pending_completion[0], struct drbd_request, req_pending_local); 1724 req_write = list_first_entry_or_null(&device->pending_completion[1], struct drbd_request, req_pending_local); 1725 1726 /* maybe the oldest request waiting for the peer is in fact still 1727 * blocking in tcp sendmsg. That's ok, though, that's handled via the 1728 * socket send timeout, requesting a ping, and bumping ko-count in 1729 * we_should_drop_the_connection(). 1730 */ 1731 1732 /* check the oldest request we did successfully sent, 1733 * but which is still waiting for an ACK. */ 1734 req_peer = connection->req_ack_pending; 1735 1736 /* if we don't have such request (e.g. protocoll A) 1737 * check the oldest requests which is still waiting on its epoch 1738 * closing barrier ack. */ 1739 if (!req_peer) 1740 req_peer = connection->req_not_net_done; 1741 1742 /* evaluate the oldest peer request only in one timer! */ 1743 if (req_peer && req_peer->device != device) 1744 req_peer = NULL; 1745 1746 /* do we have something to evaluate? */ 1747 if (req_peer == NULL && req_write == NULL && req_read == NULL) 1748 goto out; 1749 1750 oldest_submit_jif = 1751 (req_write && req_read) 1752 ? ( time_before(req_write->pre_submit_jif, req_read->pre_submit_jif) 1753 ? req_write->pre_submit_jif : req_read->pre_submit_jif ) 1754 : req_write ? req_write->pre_submit_jif 1755 : req_read ? req_read->pre_submit_jif : now; 1756 1757 if (ent && req_peer && net_timeout_reached(req_peer, connection, now, ent, ko_count, timeout)) 1758 _conn_request_state(connection, NS(conn, C_TIMEOUT), CS_VERBOSE | CS_HARD); 1759 1760 if (dt && oldest_submit_jif != now && 1761 time_after(now, oldest_submit_jif + dt) && 1762 !time_in_range(now, device->last_reattach_jif, device->last_reattach_jif + dt)) { 1763 drbd_warn(device, "Local backing device failed to meet the disk-timeout\n"); 1764 __drbd_chk_io_error(device, DRBD_FORCE_DETACH); 1765 } 1766 1767 /* Reschedule timer for the nearest not already expired timeout. 1768 * Fallback to now + min(effective network timeout, disk timeout). */ 1769 ent = (ent && req_peer && time_before(now, req_peer->pre_send_jif + ent)) 1770 ? req_peer->pre_send_jif + ent : now + et; 1771 dt = (dt && oldest_submit_jif != now && time_before(now, oldest_submit_jif + dt)) 1772 ? oldest_submit_jif + dt : now + et; 1773 nt = time_before(ent, dt) ? ent : dt; 1774 out: 1775 spin_unlock_irq(&device->resource->req_lock); 1776 mod_timer(&device->request_timer, nt); 1777 } 1778