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 22static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size); 23 24static 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 drbd_req_make_private_bio(req, bio_src); 34 req->rq_state = (bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0) 35 | (bio_op(bio_src) == REQ_OP_WRITE_SAME ? RQ_WSAME : 0) 36 | (bio_op(bio_src) == REQ_OP_WRITE_ZEROES ? RQ_ZEROES : 0) 37 | (bio_op(bio_src) == REQ_OP_DISCARD ? RQ_UNMAP : 0); 38 req->device = device; 39 req->master_bio = bio_src; 40 req->epoch = 0; 41 42 drbd_clear_interval(&req->i); 43 req->i.sector = bio_src->bi_iter.bi_sector; 44 req->i.size = bio_src->bi_iter.bi_size; 45 req->i.local = true; 46 req->i.waiting = false; 47 48 INIT_LIST_HEAD(&req->tl_requests); 49 INIT_LIST_HEAD(&req->w.list); 50 INIT_LIST_HEAD(&req->req_pending_master_completion); 51 INIT_LIST_HEAD(&req->req_pending_local); 52 53 /* one reference to be put by __drbd_make_request */ 54 atomic_set(&req->completion_ref, 1); 55 /* one kref as long as completion_ref > 0 */ 56 kref_init(&req->kref); 57 return req; 58} 59 60static void drbd_remove_request_interval(struct rb_root *root, 61 struct drbd_request *req) 62{ 63 struct drbd_device *device = req->device; 64 struct drbd_interval *i = &req->i; 65 66 drbd_remove_interval(root, i); 67 68 /* Wake up any processes waiting for this request to complete. */ 69 if (i->waiting) 70 wake_up(&device->misc_wait); 71} 72 73void drbd_req_destroy(struct kref *kref) 74{ 75 struct drbd_request *req = container_of(kref, struct drbd_request, kref); 76 struct drbd_device *device = req->device; 77 const unsigned s = req->rq_state; 78 79 if ((req->master_bio && !(s & RQ_POSTPONED)) || 80 atomic_read(&req->completion_ref) || 81 (s & RQ_LOCAL_PENDING) || 82 ((s & RQ_NET_MASK) && !(s & RQ_NET_DONE))) { 83 drbd_err(device, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n", 84 s, atomic_read(&req->completion_ref)); 85 return; 86 } 87 88 /* If called from mod_rq_state (expected normal case) or 89 * drbd_send_and_submit (the less likely normal path), this holds the 90 * req_lock, and req->tl_requests will typicaly be on ->transfer_log, 91 * though it may be still empty (never added to the transfer log). 92 * 93 * If called from do_retry(), we do NOT hold the req_lock, but we are 94 * still allowed to unconditionally list_del(&req->tl_requests), 95 * because it will be on a local on-stack list only. */ 96 list_del_init(&req->tl_requests); 97 98 /* finally remove the request from the conflict detection 99 * respective block_id verification interval tree. */ 100 if (!drbd_interval_empty(&req->i)) { 101 struct rb_root *root; 102 103 if (s & RQ_WRITE) 104 root = &device->write_requests; 105 else 106 root = &device->read_requests; 107 drbd_remove_request_interval(root, req); 108 } else if (s & (RQ_NET_MASK & ~RQ_NET_DONE) && req->i.size != 0) 109 drbd_err(device, "drbd_req_destroy: Logic BUG: interval empty, but: rq_state=0x%x, sect=%llu, size=%u\n", 110 s, (unsigned long long)req->i.sector, req->i.size); 111 112 /* if it was a write, we may have to set the corresponding 113 * bit(s) out-of-sync first. If it had a local part, we need to 114 * release the reference to the activity log. */ 115 if (s & RQ_WRITE) { 116 /* Set out-of-sync unless both OK flags are set 117 * (local only or remote failed). 118 * Other places where we set out-of-sync: 119 * READ with local io-error */ 120 121 /* There is a special case: 122 * we may notice late that IO was suspended, 123 * and postpone, or schedule for retry, a write, 124 * before it even was submitted or sent. 125 * In that case we do not want to touch the bitmap at all. 126 */ 127 if ((s & (RQ_POSTPONED|RQ_LOCAL_MASK|RQ_NET_MASK)) != RQ_POSTPONED) { 128 if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK)) 129 drbd_set_out_of_sync(device, req->i.sector, req->i.size); 130 131 if ((s & RQ_NET_OK) && (s & RQ_LOCAL_OK) && (s & RQ_NET_SIS)) 132 drbd_set_in_sync(device, req->i.sector, req->i.size); 133 } 134 135 /* one might be tempted to move the drbd_al_complete_io 136 * to the local io completion callback drbd_request_endio. 137 * but, if this was a mirror write, we may only 138 * drbd_al_complete_io after this is RQ_NET_DONE, 139 * otherwise the extent could be dropped from the al 140 * before it has actually been written on the peer. 141 * if we crash before our peer knows about the request, 142 * but after the extent has been dropped from the al, 143 * we would forget to resync the corresponding extent. 144 */ 145 if (s & RQ_IN_ACT_LOG) { 146 if (get_ldev_if_state(device, D_FAILED)) { 147 drbd_al_complete_io(device, &req->i); 148 put_ldev(device); 149 } else if (__ratelimit(&drbd_ratelimit_state)) { 150 drbd_warn(device, "Should have called drbd_al_complete_io(, %llu, %u), " 151 "but my Disk seems to have failed :(\n", 152 (unsigned long long) req->i.sector, req->i.size); 153 } 154 } 155 } 156 157 mempool_free(req, &drbd_request_mempool); 158} 159 160static void wake_all_senders(struct drbd_connection *connection) 161{ 162 wake_up(&connection->sender_work.q_wait); 163} 164 165/* must hold resource->req_lock */ 166void start_new_tl_epoch(struct drbd_connection *connection) 167{ 168 /* no point closing an epoch, if it is empty, anyways. */ 169 if (connection->current_tle_writes == 0) 170 return; 171 172 connection->current_tle_writes = 0; 173 atomic_inc(&connection->current_tle_nr); 174 wake_all_senders(connection); 175} 176 177void complete_master_bio(struct drbd_device *device, 178 struct bio_and_error *m) 179{ 180 if (unlikely(m->error)) 181 m->bio->bi_status = errno_to_blk_status(m->error); 182 bio_endio(m->bio); 183 dec_ap_bio(device); 184} 185 186 187/* Helper for __req_mod(). 188 * Set m->bio to the master bio, if it is fit to be completed, 189 * or leave it alone (it is initialized to NULL in __req_mod), 190 * if it has already been completed, or cannot be completed yet. 191 * If m->bio is set, the error status to be returned is placed in m->error. 192 */ 193static 194void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m) 195{ 196 const unsigned s = req->rq_state; 197 struct drbd_device *device = req->device; 198 int error, ok; 199 200 /* we must not complete the master bio, while it is 201 * still being processed by _drbd_send_zc_bio (drbd_send_dblock) 202 * not yet acknowledged by the peer 203 * not yet completed by the local io subsystem 204 * these flags may get cleared in any order by 205 * the worker, 206 * the receiver, 207 * the bio_endio completion callbacks. 208 */ 209 if ((s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) || 210 (s & RQ_NET_QUEUED) || (s & RQ_NET_PENDING) || 211 (s & RQ_COMPLETION_SUSP)) { 212 drbd_err(device, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s); 213 return; 214 } 215 216 if (!req->master_bio) { 217 drbd_err(device, "drbd_req_complete: Logic BUG, master_bio == NULL!\n"); 218 return; 219 } 220 221 /* 222 * figure out whether to report success or failure. 223 * 224 * report success when at least one of the operations succeeded. 225 * or, to put the other way, 226 * only report failure, when both operations failed. 227 * 228 * what to do about the failures is handled elsewhere. 229 * what we need to do here is just: complete the master_bio. 230 * 231 * local completion error, if any, has been stored as ERR_PTR 232 * in private_bio within drbd_request_endio. 233 */ 234 ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK); 235 error = PTR_ERR(req->private_bio); 236 237 /* Before we can signal completion to the upper layers, 238 * we may need to close the current transfer log epoch. 239 * We are within the request lock, so we can simply compare 240 * the request epoch number with the current transfer log 241 * epoch number. If they match, increase the current_tle_nr, 242 * and reset the transfer log epoch write_cnt. 243 */ 244 if (op_is_write(bio_op(req->master_bio)) && 245 req->epoch == atomic_read(&first_peer_device(device)->connection->current_tle_nr)) 246 start_new_tl_epoch(first_peer_device(device)->connection); 247 248 /* Update disk stats */ 249 bio_end_io_acct(req->master_bio, req->start_jif); 250 251 /* If READ failed, 252 * have it be pushed back to the retry work queue, 253 * so it will re-enter __drbd_make_request(), 254 * and be re-assigned to a suitable local or remote path, 255 * or failed if we do not have access to good data anymore. 256 * 257 * Unless it was failed early by __drbd_make_request(), 258 * because no path was available, in which case 259 * it was not even added to the transfer_log. 260 * 261 * read-ahead may fail, and will not be retried. 262 * 263 * WRITE should have used all available paths already. 264 */ 265 if (!ok && 266 bio_op(req->master_bio) == REQ_OP_READ && 267 !(req->master_bio->bi_opf & REQ_RAHEAD) && 268 !list_empty(&req->tl_requests)) 269 req->rq_state |= RQ_POSTPONED; 270 271 if (!(req->rq_state & RQ_POSTPONED)) { 272 m->error = ok ? 0 : (error ?: -EIO); 273 m->bio = req->master_bio; 274 req->master_bio = NULL; 275 /* We leave it in the tree, to be able to verify later 276 * write-acks in protocol != C during resync. 277 * But we mark it as "complete", so it won't be counted as 278 * conflict in a multi-primary setup. */ 279 req->i.completed = true; 280 } 281 282 if (req->i.waiting) 283 wake_up(&device->misc_wait); 284 285 /* Either we are about to complete to upper layers, 286 * or we will restart this request. 287 * In either case, the request object will be destroyed soon, 288 * so better remove it from all lists. */ 289 list_del_init(&req->req_pending_master_completion); 290} 291 292/* still holds resource->req_lock */ 293static void drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put) 294{ 295 struct drbd_device *device = req->device; 296 D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED)); 297 298 if (!put) 299 return; 300 301 if (!atomic_sub_and_test(put, &req->completion_ref)) 302 return; 303 304 drbd_req_complete(req, m); 305 306 /* local completion may still come in later, 307 * we need to keep the req object around. */ 308 if (req->rq_state & RQ_LOCAL_ABORTED) 309 return; 310 311 if (req->rq_state & RQ_POSTPONED) { 312 /* don't destroy the req object just yet, 313 * but queue it for retry */ 314 drbd_restart_request(req); 315 return; 316 } 317 318 kref_put(&req->kref, drbd_req_destroy); 319} 320 321static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) 322{ 323 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 324 if (!connection) 325 return; 326 if (connection->req_next == NULL) 327 connection->req_next = req; 328} 329 330static void advance_conn_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) 331{ 332 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 333 if (!connection) 334 return; 335 if (connection->req_next != req) 336 return; 337 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { 338 const unsigned s = req->rq_state; 339 if (s & RQ_NET_QUEUED) 340 break; 341 } 342 if (&req->tl_requests == &connection->transfer_log) 343 req = NULL; 344 connection->req_next = req; 345} 346 347static void set_if_null_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req) 348{ 349 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 350 if (!connection) 351 return; 352 if (connection->req_ack_pending == NULL) 353 connection->req_ack_pending = req; 354} 355 356static void advance_conn_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req) 357{ 358 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 359 if (!connection) 360 return; 361 if (connection->req_ack_pending != req) 362 return; 363 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { 364 const unsigned s = req->rq_state; 365 if ((s & RQ_NET_SENT) && (s & RQ_NET_PENDING)) 366 break; 367 } 368 if (&req->tl_requests == &connection->transfer_log) 369 req = NULL; 370 connection->req_ack_pending = req; 371} 372 373static void set_if_null_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req) 374{ 375 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 376 if (!connection) 377 return; 378 if (connection->req_not_net_done == NULL) 379 connection->req_not_net_done = req; 380} 381 382static void advance_conn_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req) 383{ 384 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; 385 if (!connection) 386 return; 387 if (connection->req_not_net_done != req) 388 return; 389 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { 390 const unsigned s = req->rq_state; 391 if ((s & RQ_NET_SENT) && !(s & RQ_NET_DONE)) 392 break; 393 } 394 if (&req->tl_requests == &connection->transfer_log) 395 req = NULL; 396 connection->req_not_net_done = req; 397} 398 399/* I'd like this to be the only place that manipulates 400 * req->completion_ref and req->kref. */ 401static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m, 402 int clear, int set) 403{ 404 struct drbd_device *device = req->device; 405 struct drbd_peer_device *peer_device = first_peer_device(device); 406 unsigned s = req->rq_state; 407 int c_put = 0; 408 409 if (drbd_suspended(device) && !((s | clear) & RQ_COMPLETION_SUSP)) 410 set |= RQ_COMPLETION_SUSP; 411 412 /* apply */ 413 414 req->rq_state &= ~clear; 415 req->rq_state |= set; 416 417 /* no change? */ 418 if (req->rq_state == s) 419 return; 420 421 /* intent: get references */ 422 423 kref_get(&req->kref); 424 425 if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING)) 426 atomic_inc(&req->completion_ref); 427 428 if (!(s & RQ_NET_PENDING) && (set & RQ_NET_PENDING)) { 429 inc_ap_pending(device); 430 atomic_inc(&req->completion_ref); 431 } 432 433 if (!(s & RQ_NET_QUEUED) && (set & RQ_NET_QUEUED)) { 434 atomic_inc(&req->completion_ref); 435 set_if_null_req_next(peer_device, req); 436 } 437 438 if (!(s & RQ_EXP_BARR_ACK) && (set & RQ_EXP_BARR_ACK)) 439 kref_get(&req->kref); /* wait for the DONE */ 440 441 if (!(s & RQ_NET_SENT) && (set & RQ_NET_SENT)) { 442 /* potentially already completed in the ack_receiver thread */ 443 if (!(s & RQ_NET_DONE)) { 444 atomic_add(req->i.size >> 9, &device->ap_in_flight); 445 set_if_null_req_not_net_done(peer_device, req); 446 } 447 if (req->rq_state & RQ_NET_PENDING) 448 set_if_null_req_ack_pending(peer_device, req); 449 } 450 451 if (!(s & RQ_COMPLETION_SUSP) && (set & RQ_COMPLETION_SUSP)) 452 atomic_inc(&req->completion_ref); 453 454 /* progress: put references */ 455 456 if ((s & RQ_COMPLETION_SUSP) && (clear & RQ_COMPLETION_SUSP)) 457 ++c_put; 458 459 if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) { 460 D_ASSERT(device, req->rq_state & RQ_LOCAL_PENDING); 461 ++c_put; 462 } 463 464 if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) { 465 if (req->rq_state & RQ_LOCAL_ABORTED) 466 kref_put(&req->kref, drbd_req_destroy); 467 else 468 ++c_put; 469 list_del_init(&req->req_pending_local); 470 } 471 472 if ((s & RQ_NET_PENDING) && (clear & RQ_NET_PENDING)) { 473 dec_ap_pending(device); 474 ++c_put; 475 req->acked_jif = jiffies; 476 advance_conn_req_ack_pending(peer_device, req); 477 } 478 479 if ((s & RQ_NET_QUEUED) && (clear & RQ_NET_QUEUED)) { 480 ++c_put; 481 advance_conn_req_next(peer_device, req); 482 } 483 484 if (!(s & RQ_NET_DONE) && (set & RQ_NET_DONE)) { 485 if (s & RQ_NET_SENT) 486 atomic_sub(req->i.size >> 9, &device->ap_in_flight); 487 if (s & RQ_EXP_BARR_ACK) 488 kref_put(&req->kref, drbd_req_destroy); 489 req->net_done_jif = jiffies; 490 491 /* in ahead/behind mode, or just in case, 492 * before we finally destroy this request, 493 * the caching pointers must not reference it anymore */ 494 advance_conn_req_next(peer_device, req); 495 advance_conn_req_ack_pending(peer_device, req); 496 advance_conn_req_not_net_done(peer_device, req); 497 } 498 499 /* potentially complete and destroy */ 500 501 /* If we made progress, retry conflicting peer requests, if any. */ 502 if (req->i.waiting) 503 wake_up(&device->misc_wait); 504 505 drbd_req_put_completion_ref(req, m, c_put); 506 kref_put(&req->kref, drbd_req_destroy); 507} 508 509static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req) 510{ 511 char b[BDEVNAME_SIZE]; 512 513 if (!__ratelimit(&drbd_ratelimit_state)) 514 return; 515 516 drbd_warn(device, "local %s IO error sector %llu+%u on %s\n", 517 (req->rq_state & RQ_WRITE) ? "WRITE" : "READ", 518 (unsigned long long)req->i.sector, 519 req->i.size >> 9, 520 bdevname(device->ldev->backing_bdev, b)); 521} 522 523/* Helper for HANDED_OVER_TO_NETWORK. 524 * Is this a protocol A write (neither WRITE_ACK nor RECEIVE_ACK expected)? 525 * Is it also still "PENDING"? 526 * --> If so, clear PENDING and set NET_OK below. 527 * If it is a protocol A write, but not RQ_PENDING anymore, neg-ack was faster 528 * (and we must not set RQ_NET_OK) */ 529static inline bool is_pending_write_protocol_A(struct drbd_request *req) 530{ 531 return (req->rq_state & 532 (RQ_WRITE|RQ_NET_PENDING|RQ_EXP_WRITE_ACK|RQ_EXP_RECEIVE_ACK)) 533 == (RQ_WRITE|RQ_NET_PENDING); 534} 535 536/* obviously this could be coded as many single functions 537 * instead of one huge switch, 538 * or by putting the code directly in the respective locations 539 * (as it has been before). 540 * 541 * but having it this way 542 * enforces that it is all in this one place, where it is easier to audit, 543 * it makes it obvious that whatever "event" "happens" to a request should 544 * happen "atomically" within the req_lock, 545 * and it enforces that we have to think in a very structured manner 546 * about the "events" that may happen to a request during its life time ... 547 */ 548int __req_mod(struct drbd_request *req, enum drbd_req_event what, 549 struct bio_and_error *m) 550{ 551 struct drbd_device *const device = req->device; 552 struct drbd_peer_device *const peer_device = first_peer_device(device); 553 struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL; 554 struct net_conf *nc; 555 int p, rv = 0; 556 557 if (m) 558 m->bio = NULL; 559 560 switch (what) { 561 default: 562 drbd_err(device, "LOGIC BUG in %s:%u\n", __FILE__ , __LINE__); 563 break; 564 565 /* does not happen... 566 * initialization done in drbd_req_new 567 case CREATED: 568 break; 569 */ 570 571 case TO_BE_SENT: /* via network */ 572 /* reached via __drbd_make_request 573 * and from w_read_retry_remote */ 574 D_ASSERT(device, !(req->rq_state & RQ_NET_MASK)); 575 rcu_read_lock(); 576 nc = rcu_dereference(connection->net_conf); 577 p = nc->wire_protocol; 578 rcu_read_unlock(); 579 req->rq_state |= 580 p == DRBD_PROT_C ? RQ_EXP_WRITE_ACK : 581 p == DRBD_PROT_B ? RQ_EXP_RECEIVE_ACK : 0; 582 mod_rq_state(req, m, 0, RQ_NET_PENDING); 583 break; 584 585 case TO_BE_SUBMITTED: /* locally */ 586 /* reached via __drbd_make_request */ 587 D_ASSERT(device, !(req->rq_state & RQ_LOCAL_MASK)); 588 mod_rq_state(req, m, 0, RQ_LOCAL_PENDING); 589 break; 590 591 case COMPLETED_OK: 592 if (req->rq_state & RQ_WRITE) 593 device->writ_cnt += req->i.size >> 9; 594 else 595 device->read_cnt += req->i.size >> 9; 596 597 mod_rq_state(req, m, RQ_LOCAL_PENDING, 598 RQ_LOCAL_COMPLETED|RQ_LOCAL_OK); 599 break; 600 601 case ABORT_DISK_IO: 602 mod_rq_state(req, m, 0, RQ_LOCAL_ABORTED); 603 break; 604 605 case WRITE_COMPLETED_WITH_ERROR: 606 drbd_report_io_error(device, req); 607 __drbd_chk_io_error(device, DRBD_WRITE_ERROR); 608 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED); 609 break; 610 611 case READ_COMPLETED_WITH_ERROR: 612 drbd_set_out_of_sync(device, req->i.sector, req->i.size); 613 drbd_report_io_error(device, req); 614 __drbd_chk_io_error(device, DRBD_READ_ERROR); 615 fallthrough; 616 case READ_AHEAD_COMPLETED_WITH_ERROR: 617 /* it is legal to fail read-ahead, no __drbd_chk_io_error in that case. */ 618 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED); 619 break; 620 621 case DISCARD_COMPLETED_NOTSUPP: 622 case DISCARD_COMPLETED_WITH_ERROR: 623 /* I'd rather not detach from local disk just because it 624 * failed a REQ_OP_DISCARD. */ 625 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED); 626 break; 627 628 case QUEUE_FOR_NET_READ: 629 /* READ, and 630 * no local disk, 631 * or target area marked as invalid, 632 * or just got an io-error. */ 633 /* from __drbd_make_request 634 * or from bio_endio during read io-error recovery */ 635 636 /* So we can verify the handle in the answer packet. 637 * Corresponding drbd_remove_request_interval is in 638 * drbd_req_complete() */ 639 D_ASSERT(device, drbd_interval_empty(&req->i)); 640 drbd_insert_interval(&device->read_requests, &req->i); 641 642 set_bit(UNPLUG_REMOTE, &device->flags); 643 644 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 645 D_ASSERT(device, (req->rq_state & RQ_LOCAL_MASK) == 0); 646 mod_rq_state(req, m, 0, RQ_NET_QUEUED); 647 req->w.cb = w_send_read_req; 648 drbd_queue_work(&connection->sender_work, 649 &req->w); 650 break; 651 652 case QUEUE_FOR_NET_WRITE: 653 /* assert something? */ 654 /* from __drbd_make_request only */ 655 656 /* Corresponding drbd_remove_request_interval is in 657 * drbd_req_complete() */ 658 D_ASSERT(device, drbd_interval_empty(&req->i)); 659 drbd_insert_interval(&device->write_requests, &req->i); 660 661 /* NOTE 662 * In case the req ended up on the transfer log before being 663 * queued on the worker, it could lead to this request being 664 * missed during cleanup after connection loss. 665 * So we have to do both operations here, 666 * within the same lock that protects the transfer log. 667 * 668 * _req_add_to_epoch(req); this has to be after the 669 * _maybe_start_new_epoch(req); which happened in 670 * __drbd_make_request, because we now may set the bit 671 * again ourselves to close the current epoch. 672 * 673 * Add req to the (now) current epoch (barrier). */ 674 675 /* otherwise we may lose an unplug, which may cause some remote 676 * io-scheduler timeout to expire, increasing maximum latency, 677 * hurting performance. */ 678 set_bit(UNPLUG_REMOTE, &device->flags); 679 680 /* queue work item to send data */ 681 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 682 mod_rq_state(req, m, 0, RQ_NET_QUEUED|RQ_EXP_BARR_ACK); 683 req->w.cb = w_send_dblock; 684 drbd_queue_work(&connection->sender_work, 685 &req->w); 686 687 /* close the epoch, in case it outgrew the limit */ 688 rcu_read_lock(); 689 nc = rcu_dereference(connection->net_conf); 690 p = nc->max_epoch_size; 691 rcu_read_unlock(); 692 if (connection->current_tle_writes >= p) 693 start_new_tl_epoch(connection); 694 695 break; 696 697 case QUEUE_FOR_SEND_OOS: 698 mod_rq_state(req, m, 0, RQ_NET_QUEUED); 699 req->w.cb = w_send_out_of_sync; 700 drbd_queue_work(&connection->sender_work, 701 &req->w); 702 break; 703 704 case READ_RETRY_REMOTE_CANCELED: 705 case SEND_CANCELED: 706 case SEND_FAILED: 707 /* real cleanup will be done from tl_clear. just update flags 708 * so it is no longer marked as on the worker queue */ 709 mod_rq_state(req, m, RQ_NET_QUEUED, 0); 710 break; 711 712 case HANDED_OVER_TO_NETWORK: 713 /* assert something? */ 714 if (is_pending_write_protocol_A(req)) 715 /* this is what is dangerous about protocol A: 716 * pretend it was successfully written on the peer. */ 717 mod_rq_state(req, m, RQ_NET_QUEUED|RQ_NET_PENDING, 718 RQ_NET_SENT|RQ_NET_OK); 719 else 720 mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_SENT); 721 /* It is still not yet RQ_NET_DONE until the 722 * corresponding epoch barrier got acked as well, 723 * so we know what to dirty on connection loss. */ 724 break; 725 726 case OOS_HANDED_TO_NETWORK: 727 /* Was not set PENDING, no longer QUEUED, so is now DONE 728 * as far as this connection is concerned. */ 729 mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_DONE); 730 break; 731 732 case CONNECTION_LOST_WHILE_PENDING: 733 /* transfer log cleanup after connection loss */ 734 mod_rq_state(req, m, 735 RQ_NET_OK|RQ_NET_PENDING|RQ_COMPLETION_SUSP, 736 RQ_NET_DONE); 737 break; 738 739 case CONFLICT_RESOLVED: 740 /* for superseded conflicting writes of multiple primaries, 741 * there is no need to keep anything in the tl, potential 742 * node crashes are covered by the activity log. 743 * 744 * If this request had been marked as RQ_POSTPONED before, 745 * it will actually not be completed, but "restarted", 746 * resubmitted from the retry worker context. */ 747 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 748 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK); 749 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_DONE|RQ_NET_OK); 750 break; 751 752 case WRITE_ACKED_BY_PEER_AND_SIS: 753 req->rq_state |= RQ_NET_SIS; 754 case WRITE_ACKED_BY_PEER: 755 /* Normal operation protocol C: successfully written on peer. 756 * During resync, even in protocol != C, 757 * we requested an explicit write ack anyways. 758 * Which means we cannot even assert anything here. 759 * Nothing more to do here. 760 * We want to keep the tl in place for all protocols, to cater 761 * for volatile write-back caches on lower level devices. */ 762 goto ack_common; 763 case RECV_ACKED_BY_PEER: 764 D_ASSERT(device, req->rq_state & RQ_EXP_RECEIVE_ACK); 765 /* protocol B; pretends to be successfully written on peer. 766 * see also notes above in HANDED_OVER_TO_NETWORK about 767 * protocol != C */ 768 ack_common: 769 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK); 770 break; 771 772 case POSTPONE_WRITE: 773 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK); 774 /* If this node has already detected the write conflict, the 775 * worker will be waiting on misc_wait. Wake it up once this 776 * request has completed locally. 777 */ 778 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 779 req->rq_state |= RQ_POSTPONED; 780 if (req->i.waiting) 781 wake_up(&device->misc_wait); 782 /* Do not clear RQ_NET_PENDING. This request will make further 783 * progress via restart_conflicting_writes() or 784 * fail_postponed_requests(). Hopefully. */ 785 break; 786 787 case NEG_ACKED: 788 mod_rq_state(req, m, RQ_NET_OK|RQ_NET_PENDING, 0); 789 break; 790 791 case FAIL_FROZEN_DISK_IO: 792 if (!(req->rq_state & RQ_LOCAL_COMPLETED)) 793 break; 794 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0); 795 break; 796 797 case RESTART_FROZEN_DISK_IO: 798 if (!(req->rq_state & RQ_LOCAL_COMPLETED)) 799 break; 800 801 mod_rq_state(req, m, 802 RQ_COMPLETION_SUSP|RQ_LOCAL_COMPLETED, 803 RQ_LOCAL_PENDING); 804 805 rv = MR_READ; 806 if (bio_data_dir(req->master_bio) == WRITE) 807 rv = MR_WRITE; 808 809 get_ldev(device); /* always succeeds in this call path */ 810 req->w.cb = w_restart_disk_io; 811 drbd_queue_work(&connection->sender_work, 812 &req->w); 813 break; 814 815 case RESEND: 816 /* Simply complete (local only) READs. */ 817 if (!(req->rq_state & RQ_WRITE) && !req->w.cb) { 818 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0); 819 break; 820 } 821 822 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK 823 before the connection loss (B&C only); only P_BARRIER_ACK 824 (or the local completion?) was missing when we suspended. 825 Throwing them out of the TL here by pretending we got a BARRIER_ACK. 826 During connection handshake, we ensure that the peer was not rebooted. */ 827 if (!(req->rq_state & RQ_NET_OK)) { 828 /* FIXME could this possibly be a req->dw.cb == w_send_out_of_sync? 829 * in that case we must not set RQ_NET_PENDING. */ 830 831 mod_rq_state(req, m, RQ_COMPLETION_SUSP, RQ_NET_QUEUED|RQ_NET_PENDING); 832 if (req->w.cb) { 833 /* w.cb expected to be w_send_dblock, or w_send_read_req */ 834 drbd_queue_work(&connection->sender_work, 835 &req->w); 836 rv = req->rq_state & RQ_WRITE ? MR_WRITE : MR_READ; 837 } /* else: FIXME can this happen? */ 838 break; 839 } 840 fallthrough; /* to BARRIER_ACKED */ 841 842 case BARRIER_ACKED: 843 /* barrier ack for READ requests does not make sense */ 844 if (!(req->rq_state & RQ_WRITE)) 845 break; 846 847 if (req->rq_state & RQ_NET_PENDING) { 848 /* barrier came in before all requests were acked. 849 * this is bad, because if the connection is lost now, 850 * we won't be able to clean them up... */ 851 drbd_err(device, "FIXME (BARRIER_ACKED but pending)\n"); 852 } 853 /* Allowed to complete requests, even while suspended. 854 * As this is called for all requests within a matching epoch, 855 * we need to filter, and only set RQ_NET_DONE for those that 856 * have actually been on the wire. */ 857 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 858 (req->rq_state & RQ_NET_MASK) ? RQ_NET_DONE : 0); 859 break; 860 861 case DATA_RECEIVED: 862 D_ASSERT(device, req->rq_state & RQ_NET_PENDING); 863 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE); 864 break; 865 866 case QUEUE_AS_DRBD_BARRIER: 867 start_new_tl_epoch(connection); 868 mod_rq_state(req, m, 0, RQ_NET_OK|RQ_NET_DONE); 869 break; 870 } 871 872 return rv; 873} 874 875/* we may do a local read if: 876 * - we are consistent (of course), 877 * - or we are generally inconsistent, 878 * BUT we are still/already IN SYNC for this area. 879 * since size may be bigger than BM_BLOCK_SIZE, 880 * we may need to check several bits. 881 */ 882static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size) 883{ 884 unsigned long sbnr, ebnr; 885 sector_t esector, nr_sectors; 886 887 if (device->state.disk == D_UP_TO_DATE) 888 return true; 889 if (device->state.disk != D_INCONSISTENT) 890 return false; 891 esector = sector + (size >> 9) - 1; 892 nr_sectors = get_capacity(device->vdisk); 893 D_ASSERT(device, sector < nr_sectors); 894 D_ASSERT(device, esector < nr_sectors); 895 896 sbnr = BM_SECT_TO_BIT(sector); 897 ebnr = BM_SECT_TO_BIT(esector); 898 899 return drbd_bm_count_bits(device, sbnr, ebnr) == 0; 900} 901 902static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t sector, 903 enum drbd_read_balancing rbm) 904{ 905 struct backing_dev_info *bdi; 906 int stripe_shift; 907 908 switch (rbm) { 909 case RB_CONGESTED_REMOTE: 910 bdi = device->ldev->backing_bdev->bd_disk->queue->backing_dev_info; 911 return bdi_read_congested(bdi); 912 case RB_LEAST_PENDING: 913 return atomic_read(&device->local_cnt) > 914 atomic_read(&device->ap_pending_cnt) + atomic_read(&device->rs_pending_cnt); 915 case RB_32K_STRIPING: /* stripe_shift = 15 */ 916 case RB_64K_STRIPING: 917 case RB_128K_STRIPING: 918 case RB_256K_STRIPING: 919 case RB_512K_STRIPING: 920 case RB_1M_STRIPING: /* stripe_shift = 20 */ 921 stripe_shift = (rbm - RB_32K_STRIPING + 15); 922 return (sector >> (stripe_shift - 9)) & 1; 923 case RB_ROUND_ROBIN: 924 return test_and_change_bit(READ_BALANCE_RR, &device->flags); 925 case RB_PREFER_REMOTE: 926 return true; 927 case RB_PREFER_LOCAL: 928 default: 929 return false; 930 } 931} 932 933/* 934 * complete_conflicting_writes - wait for any conflicting write requests 935 * 936 * The write_requests tree contains all active write requests which we 937 * currently know about. Wait for any requests to complete which conflict with 938 * the new one. 939 * 940 * Only way out: remove the conflicting intervals from the tree. 941 */ 942static void complete_conflicting_writes(struct drbd_request *req) 943{ 944 DEFINE_WAIT(wait); 945 struct drbd_device *device = req->device; 946 struct drbd_interval *i; 947 sector_t sector = req->i.sector; 948 int size = req->i.size; 949 950 for (;;) { 951 drbd_for_each_overlap(i, &device->write_requests, sector, size) { 952 /* Ignore, if already completed to upper layers. */ 953 if (i->completed) 954 continue; 955 /* Handle the first found overlap. After the schedule 956 * we have to restart the tree walk. */ 957 break; 958 } 959 if (!i) /* if any */ 960 break; 961 962 /* Indicate to wake up device->misc_wait on progress. */ 963 prepare_to_wait(&device->misc_wait, &wait, TASK_UNINTERRUPTIBLE); 964 i->waiting = true; 965 spin_unlock_irq(&device->resource->req_lock); 966 schedule(); 967 spin_lock_irq(&device->resource->req_lock); 968 } 969 finish_wait(&device->misc_wait, &wait); 970} 971 972/* called within req_lock */ 973static void maybe_pull_ahead(struct drbd_device *device) 974{ 975 struct drbd_connection *connection = first_peer_device(device)->connection; 976 struct net_conf *nc; 977 bool congested = false; 978 enum drbd_on_congestion on_congestion; 979 980 rcu_read_lock(); 981 nc = rcu_dereference(connection->net_conf); 982 on_congestion = nc ? nc->on_congestion : OC_BLOCK; 983 rcu_read_unlock(); 984 if (on_congestion == OC_BLOCK || 985 connection->agreed_pro_version < 96) 986 return; 987 988 if (on_congestion == OC_PULL_AHEAD && device->state.conn == C_AHEAD) 989 return; /* nothing to do ... */ 990 991 /* If I don't even have good local storage, we can not reasonably try 992 * to pull ahead of the peer. We also need the local reference to make 993 * sure device->act_log is there. 994 */ 995 if (!get_ldev_if_state(device, D_UP_TO_DATE)) 996 return; 997 998 if (nc->cong_fill && 999 atomic_read(&device->ap_in_flight) >= nc->cong_fill) { 1000 drbd_info(device, "Congestion-fill threshold reached\n"); 1001 congested = true; 1002 } 1003 1004 if (device->act_log->used >= nc->cong_extents) { 1005 drbd_info(device, "Congestion-extents threshold reached\n"); 1006 congested = true; 1007 } 1008 1009 if (congested) { 1010 /* start a new epoch for non-mirrored writes */ 1011 start_new_tl_epoch(first_peer_device(device)->connection); 1012 1013 if (on_congestion == OC_PULL_AHEAD) 1014 _drbd_set_state(_NS(device, conn, C_AHEAD), 0, NULL); 1015 else /*nc->on_congestion == OC_DISCONNECT */ 1016 _drbd_set_state(_NS(device, conn, C_DISCONNECTING), 0, NULL); 1017 } 1018 put_ldev(device); 1019} 1020 1021/* If this returns false, and req->private_bio is still set, 1022 * this should be submitted locally. 1023 * 1024 * If it returns false, but req->private_bio is not set, 1025 * we do not have access to good data :( 1026 * 1027 * Otherwise, this destroys req->private_bio, if any, 1028 * and returns true. 1029 */ 1030static bool do_remote_read(struct drbd_request *req) 1031{ 1032 struct drbd_device *device = req->device; 1033 enum drbd_read_balancing rbm; 1034 1035 if (req->private_bio) { 1036 if (!drbd_may_do_local_read(device, 1037 req->i.sector, req->i.size)) { 1038 bio_put(req->private_bio); 1039 req->private_bio = NULL; 1040 put_ldev(device); 1041 } 1042 } 1043 1044 if (device->state.pdsk != D_UP_TO_DATE) 1045 return false; 1046 1047 if (req->private_bio == NULL) 1048 return true; 1049 1050 /* TODO: improve read balancing decisions, take into account drbd 1051 * protocol, pending requests etc. */ 1052 1053 rcu_read_lock(); 1054 rbm = rcu_dereference(device->ldev->disk_conf)->read_balancing; 1055 rcu_read_unlock(); 1056 1057 if (rbm == RB_PREFER_LOCAL && req->private_bio) 1058 return false; /* submit locally */ 1059 1060 if (remote_due_to_read_balancing(device, req->i.sector, rbm)) { 1061 if (req->private_bio) { 1062 bio_put(req->private_bio); 1063 req->private_bio = NULL; 1064 put_ldev(device); 1065 } 1066 return true; 1067 } 1068 1069 return false; 1070} 1071 1072bool drbd_should_do_remote(union drbd_dev_state s) 1073{ 1074 return s.pdsk == D_UP_TO_DATE || 1075 (s.pdsk >= D_INCONSISTENT && 1076 s.conn >= C_WF_BITMAP_T && 1077 s.conn < C_AHEAD); 1078 /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T. 1079 That is equivalent since before 96 IO was frozen in the C_WF_BITMAP* 1080 states. */ 1081} 1082 1083static bool drbd_should_send_out_of_sync(union drbd_dev_state s) 1084{ 1085 return s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S; 1086 /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary 1087 since we enter state C_AHEAD only if proto >= 96 */ 1088} 1089 1090/* returns number of connections (== 1, for drbd 8.4) 1091 * expected to actually write this data, 1092 * which does NOT include those that we are L_AHEAD for. */ 1093static int drbd_process_write_request(struct drbd_request *req) 1094{ 1095 struct drbd_device *device = req->device; 1096 int remote, send_oos; 1097 1098 remote = drbd_should_do_remote(device->state); 1099 send_oos = drbd_should_send_out_of_sync(device->state); 1100 1101 /* Need to replicate writes. Unless it is an empty flush, 1102 * which is better mapped to a DRBD P_BARRIER packet, 1103 * also for drbd wire protocol compatibility reasons. 1104 * If this was a flush, just start a new epoch. 1105 * Unless the current epoch was empty anyways, or we are not currently 1106 * replicating, in which case there is no point. */ 1107 if (unlikely(req->i.size == 0)) { 1108 /* The only size==0 bios we expect are empty flushes. */ 1109 D_ASSERT(device, req->master_bio->bi_opf & REQ_PREFLUSH); 1110 if (remote) 1111 _req_mod(req, QUEUE_AS_DRBD_BARRIER); 1112 return remote; 1113 } 1114 1115 if (!remote && !send_oos) 1116 return 0; 1117 1118 D_ASSERT(device, !(remote && send_oos)); 1119 1120 if (remote) { 1121 _req_mod(req, TO_BE_SENT); 1122 _req_mod(req, QUEUE_FOR_NET_WRITE); 1123 } else if (drbd_set_out_of_sync(device, req->i.sector, req->i.size)) 1124 _req_mod(req, QUEUE_FOR_SEND_OOS); 1125 1126 return remote; 1127} 1128 1129static void drbd_process_discard_or_zeroes_req(struct drbd_request *req, int flags) 1130{ 1131 int err = drbd_issue_discard_or_zero_out(req->device, 1132 req->i.sector, req->i.size >> 9, flags); 1133 if (err) 1134 req->private_bio->bi_status = BLK_STS_IOERR; 1135 bio_endio(req->private_bio); 1136} 1137 1138static void 1139drbd_submit_req_private_bio(struct drbd_request *req) 1140{ 1141 struct drbd_device *device = req->device; 1142 struct bio *bio = req->private_bio; 1143 unsigned int type; 1144 1145 if (bio_op(bio) != REQ_OP_READ) 1146 type = DRBD_FAULT_DT_WR; 1147 else if (bio->bi_opf & REQ_RAHEAD) 1148 type = DRBD_FAULT_DT_RA; 1149 else 1150 type = DRBD_FAULT_DT_RD; 1151 1152 bio_set_dev(bio, device->ldev->backing_bdev); 1153 1154 /* State may have changed since we grabbed our reference on the 1155 * ->ldev member. Double check, and short-circuit to endio. 1156 * In case the last activity log transaction failed to get on 1157 * stable storage, and this is a WRITE, we may not even submit 1158 * this bio. */ 1159 if (get_ldev(device)) { 1160 if (drbd_insert_fault(device, type)) 1161 bio_io_error(bio); 1162 else if (bio_op(bio) == REQ_OP_WRITE_ZEROES) 1163 drbd_process_discard_or_zeroes_req(req, EE_ZEROOUT | 1164 ((bio->bi_opf & REQ_NOUNMAP) ? 0 : EE_TRIM)); 1165 else if (bio_op(bio) == REQ_OP_DISCARD) 1166 drbd_process_discard_or_zeroes_req(req, EE_TRIM); 1167 else 1168 submit_bio_noacct(bio); 1169 put_ldev(device); 1170 } else 1171 bio_io_error(bio); 1172} 1173 1174static void drbd_queue_write(struct drbd_device *device, struct drbd_request *req) 1175{ 1176 spin_lock_irq(&device->resource->req_lock); 1177 list_add_tail(&req->tl_requests, &device->submit.writes); 1178 list_add_tail(&req->req_pending_master_completion, 1179 &device->pending_master_completion[1 /* WRITE */]); 1180 spin_unlock_irq(&device->resource->req_lock); 1181 queue_work(device->submit.wq, &device->submit.worker); 1182 /* do_submit() may sleep internally on al_wait, too */ 1183 wake_up(&device->al_wait); 1184} 1185 1186/* returns the new drbd_request pointer, if the caller is expected to 1187 * drbd_send_and_submit() it (to save latency), or NULL if we queued the 1188 * request on the submitter thread. 1189 * Returns ERR_PTR(-ENOMEM) if we cannot allocate a drbd_request. 1190 */ 1191static struct drbd_request * 1192drbd_request_prepare(struct drbd_device *device, struct bio *bio, unsigned long start_jif) 1193{ 1194 const int rw = bio_data_dir(bio); 1195 struct drbd_request *req; 1196 1197 /* allocate outside of all locks; */ 1198 req = drbd_req_new(device, bio); 1199 if (!req) { 1200 dec_ap_bio(device); 1201 /* only pass the error to the upper layers. 1202 * if user cannot handle io errors, that's not our business. */ 1203 drbd_err(device, "could not kmalloc() req\n"); 1204 bio->bi_status = BLK_STS_RESOURCE; 1205 bio_endio(bio); 1206 return ERR_PTR(-ENOMEM); 1207 } 1208 1209 /* Update disk stats */ 1210 req->start_jif = bio_start_io_acct(req->master_bio); 1211 1212 if (!get_ldev(device)) { 1213 bio_put(req->private_bio); 1214 req->private_bio = NULL; 1215 } 1216 1217 /* process discards always from our submitter thread */ 1218 if (bio_op(bio) == REQ_OP_WRITE_ZEROES || 1219 bio_op(bio) == REQ_OP_DISCARD) 1220 goto queue_for_submitter_thread; 1221 1222 if (rw == WRITE && req->private_bio && req->i.size 1223 && !test_bit(AL_SUSPENDED, &device->flags)) { 1224 if (!drbd_al_begin_io_fastpath(device, &req->i)) 1225 goto queue_for_submitter_thread; 1226 req->rq_state |= RQ_IN_ACT_LOG; 1227 req->in_actlog_jif = jiffies; 1228 } 1229 return req; 1230 1231 queue_for_submitter_thread: 1232 atomic_inc(&device->ap_actlog_cnt); 1233 drbd_queue_write(device, req); 1234 return NULL; 1235} 1236 1237/* Require at least one path to current data. 1238 * We don't want to allow writes on C_STANDALONE D_INCONSISTENT: 1239 * We would not allow to read what was written, 1240 * we would not have bumped the data generation uuids, 1241 * we would cause data divergence for all the wrong reasons. 1242 * 1243 * If we don't see at least one D_UP_TO_DATE, we will fail this request, 1244 * which either returns EIO, or, if OND_SUSPEND_IO is set, suspends IO, 1245 * and queues for retry later. 1246 */ 1247static bool may_do_writes(struct drbd_device *device) 1248{ 1249 const union drbd_dev_state s = device->state; 1250 return s.disk == D_UP_TO_DATE || s.pdsk == D_UP_TO_DATE; 1251} 1252 1253struct drbd_plug_cb { 1254 struct blk_plug_cb cb; 1255 struct drbd_request *most_recent_req; 1256 /* do we need more? */ 1257}; 1258 1259static void drbd_unplug(struct blk_plug_cb *cb, bool from_schedule) 1260{ 1261 struct drbd_plug_cb *plug = container_of(cb, struct drbd_plug_cb, cb); 1262 struct drbd_resource *resource = plug->cb.data; 1263 struct drbd_request *req = plug->most_recent_req; 1264 1265 kfree(cb); 1266 if (!req) 1267 return; 1268 1269 spin_lock_irq(&resource->req_lock); 1270 /* In case the sender did not process it yet, raise the flag to 1271 * have it followed with P_UNPLUG_REMOTE just after. */ 1272 req->rq_state |= RQ_UNPLUG; 1273 /* but also queue a generic unplug */ 1274 drbd_queue_unplug(req->device); 1275 kref_put(&req->kref, drbd_req_destroy); 1276 spin_unlock_irq(&resource->req_lock); 1277} 1278 1279static struct drbd_plug_cb* drbd_check_plugged(struct drbd_resource *resource) 1280{ 1281 /* A lot of text to say 1282 * return (struct drbd_plug_cb*)blk_check_plugged(); */ 1283 struct drbd_plug_cb *plug; 1284 struct blk_plug_cb *cb = blk_check_plugged(drbd_unplug, resource, sizeof(*plug)); 1285 1286 if (cb) 1287 plug = container_of(cb, struct drbd_plug_cb, cb); 1288 else 1289 plug = NULL; 1290 return plug; 1291} 1292 1293static void drbd_update_plug(struct drbd_plug_cb *plug, struct drbd_request *req) 1294{ 1295 struct drbd_request *tmp = plug->most_recent_req; 1296 /* Will be sent to some peer. 1297 * Remember to tag it with UNPLUG_REMOTE on unplug */ 1298 kref_get(&req->kref); 1299 plug->most_recent_req = req; 1300 if (tmp) 1301 kref_put(&tmp->kref, drbd_req_destroy); 1302} 1303 1304static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request *req) 1305{ 1306 struct drbd_resource *resource = device->resource; 1307 const int rw = bio_data_dir(req->master_bio); 1308 struct bio_and_error m = { NULL, }; 1309 bool no_remote = false; 1310 bool submit_private_bio = false; 1311 1312 spin_lock_irq(&resource->req_lock); 1313 if (rw == WRITE) { 1314 /* This may temporarily give up the req_lock, 1315 * but will re-aquire it before it returns here. 1316 * Needs to be before the check on drbd_suspended() */ 1317 complete_conflicting_writes(req); 1318 /* no more giving up req_lock from now on! */ 1319 1320 /* check for congestion, and potentially stop sending 1321 * full data updates, but start sending "dirty bits" only. */ 1322 maybe_pull_ahead(device); 1323 } 1324 1325 1326 if (drbd_suspended(device)) { 1327 /* push back and retry: */ 1328 req->rq_state |= RQ_POSTPONED; 1329 if (req->private_bio) { 1330 bio_put(req->private_bio); 1331 req->private_bio = NULL; 1332 put_ldev(device); 1333 } 1334 goto out; 1335 } 1336 1337 /* We fail READ early, if we can not serve it. 1338 * We must do this before req is registered on any lists. 1339 * Otherwise, drbd_req_complete() will queue failed READ for retry. */ 1340 if (rw != WRITE) { 1341 if (!do_remote_read(req) && !req->private_bio) 1342 goto nodata; 1343 } 1344 1345 /* which transfer log epoch does this belong to? */ 1346 req->epoch = atomic_read(&first_peer_device(device)->connection->current_tle_nr); 1347 1348 /* no point in adding empty flushes to the transfer log, 1349 * they are mapped to drbd barriers already. */ 1350 if (likely(req->i.size!=0)) { 1351 if (rw == WRITE) 1352 first_peer_device(device)->connection->current_tle_writes++; 1353 1354 list_add_tail(&req->tl_requests, &first_peer_device(device)->connection->transfer_log); 1355 } 1356 1357 if (rw == WRITE) { 1358 if (req->private_bio && !may_do_writes(device)) { 1359 bio_put(req->private_bio); 1360 req->private_bio = NULL; 1361 put_ldev(device); 1362 goto nodata; 1363 } 1364 if (!drbd_process_write_request(req)) 1365 no_remote = true; 1366 } else { 1367 /* We either have a private_bio, or we can read from remote. 1368 * Otherwise we had done the goto nodata above. */ 1369 if (req->private_bio == NULL) { 1370 _req_mod(req, TO_BE_SENT); 1371 _req_mod(req, QUEUE_FOR_NET_READ); 1372 } else 1373 no_remote = true; 1374 } 1375 1376 if (no_remote == false) { 1377 struct drbd_plug_cb *plug = drbd_check_plugged(resource); 1378 if (plug) 1379 drbd_update_plug(plug, req); 1380 } 1381 1382 /* If it took the fast path in drbd_request_prepare, add it here. 1383 * The slow path has added it already. */ 1384 if (list_empty(&req->req_pending_master_completion)) 1385 list_add_tail(&req->req_pending_master_completion, 1386 &device->pending_master_completion[rw == WRITE]); 1387 if (req->private_bio) { 1388 /* needs to be marked within the same spinlock */ 1389 req->pre_submit_jif = jiffies; 1390 list_add_tail(&req->req_pending_local, 1391 &device->pending_completion[rw == WRITE]); 1392 _req_mod(req, TO_BE_SUBMITTED); 1393 /* but we need to give up the spinlock to submit */ 1394 submit_private_bio = true; 1395 } else if (no_remote) { 1396nodata: 1397 if (__ratelimit(&drbd_ratelimit_state)) 1398 drbd_err(device, "IO ERROR: neither local nor remote data, sector %llu+%u\n", 1399 (unsigned long long)req->i.sector, req->i.size >> 9); 1400 /* A write may have been queued for send_oos, however. 1401 * So we can not simply free it, we must go through drbd_req_put_completion_ref() */ 1402 } 1403 1404out: 1405 drbd_req_put_completion_ref(req, &m, 1); 1406 spin_unlock_irq(&resource->req_lock); 1407 1408 /* Even though above is a kref_put(), this is safe. 1409 * As long as we still need to submit our private bio, 1410 * we hold a completion ref, and the request cannot disappear. 1411 * If however this request did not even have a private bio to submit 1412 * (e.g. remote read), req may already be invalid now. 1413 * That's why we cannot check on req->private_bio. */ 1414 if (submit_private_bio) 1415 drbd_submit_req_private_bio(req); 1416 if (m.bio) 1417 complete_master_bio(device, &m); 1418} 1419 1420void __drbd_make_request(struct drbd_device *device, struct bio *bio, unsigned long start_jif) 1421{ 1422 struct drbd_request *req = drbd_request_prepare(device, bio, start_jif); 1423 if (IS_ERR_OR_NULL(req)) 1424 return; 1425 drbd_send_and_submit(device, req); 1426} 1427 1428static void submit_fast_path(struct drbd_device *device, struct list_head *incoming) 1429{ 1430 struct blk_plug plug; 1431 struct drbd_request *req, *tmp; 1432 1433 blk_start_plug(&plug); 1434 list_for_each_entry_safe(req, tmp, incoming, tl_requests) { 1435 const int rw = bio_data_dir(req->master_bio); 1436 1437 if (rw == WRITE /* rw != WRITE should not even end up here! */ 1438 && req->private_bio && req->i.size 1439 && !test_bit(AL_SUSPENDED, &device->flags)) { 1440 if (!drbd_al_begin_io_fastpath(device, &req->i)) 1441 continue; 1442 1443 req->rq_state |= RQ_IN_ACT_LOG; 1444 req->in_actlog_jif = jiffies; 1445 atomic_dec(&device->ap_actlog_cnt); 1446 } 1447 1448 list_del_init(&req->tl_requests); 1449 drbd_send_and_submit(device, req); 1450 } 1451 blk_finish_plug(&plug); 1452} 1453 1454static bool prepare_al_transaction_nonblock(struct drbd_device *device, 1455 struct list_head *incoming, 1456 struct list_head *pending, 1457 struct list_head *later) 1458{ 1459 struct drbd_request *req; 1460 int wake = 0; 1461 int err; 1462 1463 spin_lock_irq(&device->al_lock); 1464 while ((req = list_first_entry_or_null(incoming, struct drbd_request, tl_requests))) { 1465 err = drbd_al_begin_io_nonblock(device, &req->i); 1466 if (err == -ENOBUFS) 1467 break; 1468 if (err == -EBUSY) 1469 wake = 1; 1470 if (err) 1471 list_move_tail(&req->tl_requests, later); 1472 else 1473 list_move_tail(&req->tl_requests, pending); 1474 } 1475 spin_unlock_irq(&device->al_lock); 1476 if (wake) 1477 wake_up(&device->al_wait); 1478 return !list_empty(pending); 1479} 1480 1481static void send_and_submit_pending(struct drbd_device *device, struct list_head *pending) 1482{ 1483 struct blk_plug plug; 1484 struct drbd_request *req; 1485 1486 blk_start_plug(&plug); 1487 while ((req = list_first_entry_or_null(pending, struct drbd_request, tl_requests))) { 1488 req->rq_state |= RQ_IN_ACT_LOG; 1489 req->in_actlog_jif = jiffies; 1490 atomic_dec(&device->ap_actlog_cnt); 1491 list_del_init(&req->tl_requests); 1492 drbd_send_and_submit(device, req); 1493 } 1494 blk_finish_plug(&plug); 1495} 1496 1497void do_submit(struct work_struct *ws) 1498{ 1499 struct drbd_device *device = container_of(ws, struct drbd_device, submit.worker); 1500 LIST_HEAD(incoming); /* from drbd_make_request() */ 1501 LIST_HEAD(pending); /* to be submitted after next AL-transaction commit */ 1502 LIST_HEAD(busy); /* blocked by resync requests */ 1503 1504 /* grab new incoming requests */ 1505 spin_lock_irq(&device->resource->req_lock); 1506 list_splice_tail_init(&device->submit.writes, &incoming); 1507 spin_unlock_irq(&device->resource->req_lock); 1508 1509 for (;;) { 1510 DEFINE_WAIT(wait); 1511 1512 /* move used-to-be-busy back to front of incoming */ 1513 list_splice_init(&busy, &incoming); 1514 submit_fast_path(device, &incoming); 1515 if (list_empty(&incoming)) 1516 break; 1517 1518 for (;;) { 1519 prepare_to_wait(&device->al_wait, &wait, TASK_UNINTERRUPTIBLE); 1520 1521 list_splice_init(&busy, &incoming); 1522 prepare_al_transaction_nonblock(device, &incoming, &pending, &busy); 1523 if (!list_empty(&pending)) 1524 break; 1525 1526 schedule(); 1527 1528 /* If all currently "hot" activity log extents are kept busy by 1529 * incoming requests, we still must not totally starve new 1530 * requests to "cold" extents. 1531 * Something left on &incoming means there had not been 1532 * enough update slots available, and the activity log 1533 * has been marked as "starving". 1534 * 1535 * Try again now, without looking for new requests, 1536 * effectively blocking all new requests until we made 1537 * at least _some_ progress with what we currently have. 1538 */ 1539 if (!list_empty(&incoming)) 1540 continue; 1541 1542 /* Nothing moved to pending, but nothing left 1543 * on incoming: all moved to busy! 1544 * Grab new and iterate. */ 1545 spin_lock_irq(&device->resource->req_lock); 1546 list_splice_tail_init(&device->submit.writes, &incoming); 1547 spin_unlock_irq(&device->resource->req_lock); 1548 } 1549 finish_wait(&device->al_wait, &wait); 1550 1551 /* If the transaction was full, before all incoming requests 1552 * had been processed, skip ahead to commit, and iterate 1553 * without splicing in more incoming requests from upper layers. 1554 * 1555 * Else, if all incoming have been processed, 1556 * they have become either "pending" (to be submitted after 1557 * next transaction commit) or "busy" (blocked by resync). 1558 * 1559 * Maybe more was queued, while we prepared the transaction? 1560 * Try to stuff those into this transaction as well. 1561 * Be strictly non-blocking here, 1562 * we already have something to commit. 1563 * 1564 * Commit if we don't make any more progres. 1565 */ 1566 1567 while (list_empty(&incoming)) { 1568 LIST_HEAD(more_pending); 1569 LIST_HEAD(more_incoming); 1570 bool made_progress; 1571 1572 /* It is ok to look outside the lock, 1573 * it's only an optimization anyways */ 1574 if (list_empty(&device->submit.writes)) 1575 break; 1576 1577 spin_lock_irq(&device->resource->req_lock); 1578 list_splice_tail_init(&device->submit.writes, &more_incoming); 1579 spin_unlock_irq(&device->resource->req_lock); 1580 1581 if (list_empty(&more_incoming)) 1582 break; 1583 1584 made_progress = prepare_al_transaction_nonblock(device, &more_incoming, &more_pending, &busy); 1585 1586 list_splice_tail_init(&more_pending, &pending); 1587 list_splice_tail_init(&more_incoming, &incoming); 1588 if (!made_progress) 1589 break; 1590 } 1591 1592 drbd_al_begin_io_commit(device); 1593 send_and_submit_pending(device, &pending); 1594 } 1595} 1596 1597blk_qc_t drbd_submit_bio(struct bio *bio) 1598{ 1599 struct drbd_device *device = bio->bi_disk->private_data; 1600 unsigned long start_jif; 1601 1602 blk_queue_split(&bio); 1603 1604 start_jif = jiffies; 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, start_jif); 1613 return BLK_QC_T_NONE; 1614} 1615 1616static 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 1688void 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; 1774out: 1775 spin_unlock_irq(&device->resource->req_lock); 1776 mod_timer(&device->request_timer, nt); 1777} 1778