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