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1// SPDX-License-Identifier: GPL-2.0-only
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 <[email protected]>.
9 Copyright (C) 2002-2008, Lars Ellenberg <[email protected]>.
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 req->rq_state = (bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0)
34 | (bio_op(bio_src) == REQ_OP_WRITE_ZEROES ? RQ_ZEROES : 0)
35 | (bio_op(bio_src) == REQ_OP_DISCARD ? RQ_UNMAP : 0);
36 req->device = device;
37 req->master_bio = bio_src;
38 req->epoch = 0;
39
40 drbd_clear_interval(&req->i);
41 req->i.sector = bio_src->bi_iter.bi_sector;
42 req->i.size = bio_src->bi_iter.bi_size;
43 req->i.local = true;
44 req->i.waiting = false;
45
46 INIT_LIST_HEAD(&req->tl_requests);
47 INIT_LIST_HEAD(&req->w.list);
48 INIT_LIST_HEAD(&req->req_pending_master_completion);
49 INIT_LIST_HEAD(&req->req_pending_local);
50
51 /* one reference to be put by __drbd_make_request */
52 atomic_set(&req->completion_ref, 1);
53 /* one kref as long as completion_ref > 0 */
54 kref_init(&req->kref);
55 return req;
56}
57
58static void drbd_remove_request_interval(struct rb_root *root,
59 struct drbd_request *req)
60{
61 struct drbd_device *device = req->device;
62 struct drbd_interval *i = &req->i;
63
64 drbd_remove_interval(root, i);
65
66 /* Wake up any processes waiting for this request to complete. */
67 if (i->waiting)
68 wake_up(&device->misc_wait);
69}
70
71void drbd_req_destroy(struct kref *kref)
72{
73 struct drbd_request *req = container_of(kref, struct drbd_request, kref);
74 struct drbd_device *device = req->device;
75 const unsigned s = req->rq_state;
76
77 if ((req->master_bio && !(s & RQ_POSTPONED)) ||
78 atomic_read(&req->completion_ref) ||
79 (s & RQ_LOCAL_PENDING) ||
80 ((s & RQ_NET_MASK) && !(s & RQ_NET_DONE))) {
81 drbd_err(device, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n",
82 s, atomic_read(&req->completion_ref));
83 return;
84 }
85
86 /* If called from mod_rq_state (expected normal case) or
87 * drbd_send_and_submit (the less likely normal path), this holds the
88 * req_lock, and req->tl_requests will typicaly be on ->transfer_log,
89 * though it may be still empty (never added to the transfer log).
90 *
91 * If called from do_retry(), we do NOT hold the req_lock, but we are
92 * still allowed to unconditionally list_del(&req->tl_requests),
93 * because it will be on a local on-stack list only. */
94 list_del_init(&req->tl_requests);
95
96 /* finally remove the request from the conflict detection
97 * respective block_id verification interval tree. */
98 if (!drbd_interval_empty(&req->i)) {
99 struct rb_root *root;
100
101 if (s & RQ_WRITE)
102 root = &device->write_requests;
103 else
104 root = &device->read_requests;
105 drbd_remove_request_interval(root, req);
106 } else if (s & (RQ_NET_MASK & ~RQ_NET_DONE) && req->i.size != 0)
107 drbd_err(device, "drbd_req_destroy: Logic BUG: interval empty, but: rq_state=0x%x, sect=%llu, size=%u\n",
108 s, (unsigned long long)req->i.sector, req->i.size);
109
110 /* if it was a write, we may have to set the corresponding
111 * bit(s) out-of-sync first. If it had a local part, we need to
112 * release the reference to the activity log. */
113 if (s & RQ_WRITE) {
114 /* Set out-of-sync unless both OK flags are set
115 * (local only or remote failed).
116 * Other places where we set out-of-sync:
117 * READ with local io-error */
118
119 /* There is a special case:
120 * we may notice late that IO was suspended,
121 * and postpone, or schedule for retry, a write,
122 * before it even was submitted or sent.
123 * In that case we do not want to touch the bitmap at all.
124 */
125 struct drbd_peer_device *peer_device = first_peer_device(device);
126 if ((s & (RQ_POSTPONED|RQ_LOCAL_MASK|RQ_NET_MASK)) != RQ_POSTPONED) {
127 if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK))
128 drbd_set_out_of_sync(peer_device, req->i.sector, req->i.size);
129
130 if ((s & RQ_NET_OK) && (s & RQ_LOCAL_OK) && (s & RQ_NET_SIS))
131 drbd_set_in_sync(peer_device, req->i.sector, req->i.size);
132 }
133
134 /* one might be tempted to move the drbd_al_complete_io
135 * to the local io completion callback drbd_request_endio.
136 * but, if this was a mirror write, we may only
137 * drbd_al_complete_io after this is RQ_NET_DONE,
138 * otherwise the extent could be dropped from the al
139 * before it has actually been written on the peer.
140 * if we crash before our peer knows about the request,
141 * but after the extent has been dropped from the al,
142 * we would forget to resync the corresponding extent.
143 */
144 if (s & RQ_IN_ACT_LOG) {
145 if (get_ldev_if_state(device, D_FAILED)) {
146 drbd_al_complete_io(device, &req->i);
147 put_ldev(device);
148 } else if (drbd_ratelimit()) {
149 drbd_warn(device, "Should have called drbd_al_complete_io(, %llu, %u), "
150 "but my Disk seems to have failed :(\n",
151 (unsigned long long) req->i.sector, req->i.size);
152 }
153 }
154 }
155
156 mempool_free(req, &drbd_request_mempool);
157}
158
159static void wake_all_senders(struct drbd_connection *connection)
160{
161 wake_up(&connection->sender_work.q_wait);
162}
163
164/* must hold resource->req_lock */
165void start_new_tl_epoch(struct drbd_connection *connection)
166{
167 /* no point closing an epoch, if it is empty, anyways. */
168 if (connection->current_tle_writes == 0)
169 return;
170
171 connection->current_tle_writes = 0;
172 atomic_inc(&connection->current_tle_nr);
173 wake_all_senders(connection);
174}
175
176void complete_master_bio(struct drbd_device *device,
177 struct bio_and_error *m)
178{
179 if (unlikely(m->error))
180 m->bio->bi_status = errno_to_blk_status(m->error);
181 bio_endio(m->bio);
182 dec_ap_bio(device);
183}
184
185
186/* Helper for __req_mod().
187 * Set m->bio to the master bio, if it is fit to be completed,
188 * or leave it alone (it is initialized to NULL in __req_mod),
189 * if it has already been completed, or cannot be completed yet.
190 * If m->bio is set, the error status to be returned is placed in m->error.
191 */
192static
193void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m)
194{
195 const unsigned s = req->rq_state;
196 struct drbd_device *device = req->device;
197 int error, ok;
198
199 /* we must not complete the master bio, while it is
200 * still being processed by _drbd_send_zc_bio (drbd_send_dblock)
201 * not yet acknowledged by the peer
202 * not yet completed by the local io subsystem
203 * these flags may get cleared in any order by
204 * the worker,
205 * the receiver,
206 * the bio_endio completion callbacks.
207 */
208 if ((s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) ||
209 (s & RQ_NET_QUEUED) || (s & RQ_NET_PENDING) ||
210 (s & RQ_COMPLETION_SUSP)) {
211 drbd_err(device, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s);
212 return;
213 }
214
215 if (!req->master_bio) {
216 drbd_err(device, "drbd_req_complete: Logic BUG, master_bio == NULL!\n");
217 return;
218 }
219
220 /*
221 * figure out whether to report success or failure.
222 *
223 * report success when at least one of the operations succeeded.
224 * or, to put the other way,
225 * only report failure, when both operations failed.
226 *
227 * what to do about the failures is handled elsewhere.
228 * what we need to do here is just: complete the master_bio.
229 *
230 * local completion error, if any, has been stored as ERR_PTR
231 * in private_bio within drbd_request_endio.
232 */
233 ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK);
234 error = PTR_ERR(req->private_bio);
235
236 /* Before we can signal completion to the upper layers,
237 * we may need to close the current transfer log epoch.
238 * We are within the request lock, so we can simply compare
239 * the request epoch number with the current transfer log
240 * epoch number. If they match, increase the current_tle_nr,
241 * and reset the transfer log epoch write_cnt.
242 */
243 if (op_is_write(bio_op(req->master_bio)) &&
244 req->epoch == atomic_read(&first_peer_device(device)->connection->current_tle_nr))
245 start_new_tl_epoch(first_peer_device(device)->connection);
246
247 /* Update disk stats */
248 bio_end_io_acct(req->master_bio, req->start_jif);
249
250 /* If READ failed,
251 * have it be pushed back to the retry work queue,
252 * so it will re-enter __drbd_make_request(),
253 * and be re-assigned to a suitable local or remote path,
254 * or failed if we do not have access to good data anymore.
255 *
256 * Unless it was failed early by __drbd_make_request(),
257 * because no path was available, in which case
258 * it was not even added to the transfer_log.
259 *
260 * read-ahead may fail, and will not be retried.
261 *
262 * WRITE should have used all available paths already.
263 */
264 if (!ok &&
265 bio_op(req->master_bio) == REQ_OP_READ &&
266 !(req->master_bio->bi_opf & REQ_RAHEAD) &&
267 !list_empty(&req->tl_requests))
268 req->rq_state |= RQ_POSTPONED;
269
270 if (!(req->rq_state & RQ_POSTPONED)) {
271 m->error = ok ? 0 : (error ?: -EIO);
272 m->bio = req->master_bio;
273 req->master_bio = NULL;
274 /* We leave it in the tree, to be able to verify later
275 * write-acks in protocol != C during resync.
276 * But we mark it as "complete", so it won't be counted as
277 * conflict in a multi-primary setup. */
278 req->i.completed = true;
279 }
280
281 if (req->i.waiting)
282 wake_up(&device->misc_wait);
283
284 /* Either we are about to complete to upper layers,
285 * or we will restart this request.
286 * In either case, the request object will be destroyed soon,
287 * so better remove it from all lists. */
288 list_del_init(&req->req_pending_master_completion);
289}
290
291/* still holds resource->req_lock */
292static void drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put)
293{
294 struct drbd_device *device = req->device;
295 D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED));
296
297 if (!put)
298 return;
299
300 if (!atomic_sub_and_test(put, &req->completion_ref))
301 return;
302
303 drbd_req_complete(req, m);
304
305 /* local completion may still come in later,
306 * we need to keep the req object around. */
307 if (req->rq_state & RQ_LOCAL_ABORTED)
308 return;
309
310 if (req->rq_state & RQ_POSTPONED) {
311 /* don't destroy the req object just yet,
312 * but queue it for retry */
313 drbd_restart_request(req);
314 return;
315 }
316
317 kref_put(&req->kref, drbd_req_destroy);
318}
319
320static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req)
321{
322 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
323 if (!connection)
324 return;
325 if (connection->req_next == NULL)
326 connection->req_next = req;
327}
328
329static void advance_conn_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req)
330{
331 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
332 struct drbd_request *iter = req;
333 if (!connection)
334 return;
335 if (connection->req_next != req)
336 return;
337
338 req = NULL;
339 list_for_each_entry_continue(iter, &connection->transfer_log, tl_requests) {
340 const unsigned int s = iter->rq_state;
341
342 if (s & RQ_NET_QUEUED) {
343 req = iter;
344 break;
345 }
346 }
347 connection->req_next = req;
348}
349
350static 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
359static 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 struct drbd_request *iter = req;
363 if (!connection)
364 return;
365 if (connection->req_ack_pending != req)
366 return;
367
368 req = NULL;
369 list_for_each_entry_continue(iter, &connection->transfer_log, tl_requests) {
370 const unsigned int s = iter->rq_state;
371
372 if ((s & RQ_NET_SENT) && (s & RQ_NET_PENDING)) {
373 req = iter;
374 break;
375 }
376 }
377 connection->req_ack_pending = req;
378}
379
380static void set_if_null_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req)
381{
382 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
383 if (!connection)
384 return;
385 if (connection->req_not_net_done == NULL)
386 connection->req_not_net_done = req;
387}
388
389static void advance_conn_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req)
390{
391 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
392 struct drbd_request *iter = req;
393 if (!connection)
394 return;
395 if (connection->req_not_net_done != req)
396 return;
397
398 req = NULL;
399 list_for_each_entry_continue(iter, &connection->transfer_log, tl_requests) {
400 const unsigned int s = iter->rq_state;
401
402 if ((s & RQ_NET_SENT) && !(s & RQ_NET_DONE)) {
403 req = iter;
404 break;
405 }
406 }
407 connection->req_not_net_done = req;
408}
409
410/* I'd like this to be the only place that manipulates
411 * req->completion_ref and req->kref. */
412static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
413 int clear, int set)
414{
415 struct drbd_device *device = req->device;
416 struct drbd_peer_device *peer_device = first_peer_device(device);
417 unsigned s = req->rq_state;
418 int c_put = 0;
419
420 if (drbd_suspended(device) && !((s | clear) & RQ_COMPLETION_SUSP))
421 set |= RQ_COMPLETION_SUSP;
422
423 /* apply */
424
425 req->rq_state &= ~clear;
426 req->rq_state |= set;
427
428 /* no change? */
429 if (req->rq_state == s)
430 return;
431
432 /* intent: get references */
433
434 kref_get(&req->kref);
435
436 if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING))
437 atomic_inc(&req->completion_ref);
438
439 if (!(s & RQ_NET_PENDING) && (set & RQ_NET_PENDING)) {
440 inc_ap_pending(device);
441 atomic_inc(&req->completion_ref);
442 }
443
444 if (!(s & RQ_NET_QUEUED) && (set & RQ_NET_QUEUED)) {
445 atomic_inc(&req->completion_ref);
446 set_if_null_req_next(peer_device, req);
447 }
448
449 if (!(s & RQ_EXP_BARR_ACK) && (set & RQ_EXP_BARR_ACK))
450 kref_get(&req->kref); /* wait for the DONE */
451
452 if (!(s & RQ_NET_SENT) && (set & RQ_NET_SENT)) {
453 /* potentially already completed in the ack_receiver thread */
454 if (!(s & RQ_NET_DONE)) {
455 atomic_add(req->i.size >> 9, &device->ap_in_flight);
456 set_if_null_req_not_net_done(peer_device, req);
457 }
458 if (req->rq_state & RQ_NET_PENDING)
459 set_if_null_req_ack_pending(peer_device, req);
460 }
461
462 if (!(s & RQ_COMPLETION_SUSP) && (set & RQ_COMPLETION_SUSP))
463 atomic_inc(&req->completion_ref);
464
465 /* progress: put references */
466
467 if ((s & RQ_COMPLETION_SUSP) && (clear & RQ_COMPLETION_SUSP))
468 ++c_put;
469
470 if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) {
471 D_ASSERT(device, req->rq_state & RQ_LOCAL_PENDING);
472 ++c_put;
473 }
474
475 if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) {
476 if (req->rq_state & RQ_LOCAL_ABORTED)
477 kref_put(&req->kref, drbd_req_destroy);
478 else
479 ++c_put;
480 list_del_init(&req->req_pending_local);
481 }
482
483 if ((s & RQ_NET_PENDING) && (clear & RQ_NET_PENDING)) {
484 dec_ap_pending(device);
485 ++c_put;
486 req->acked_jif = jiffies;
487 advance_conn_req_ack_pending(peer_device, req);
488 }
489
490 if ((s & RQ_NET_QUEUED) && (clear & RQ_NET_QUEUED)) {
491 ++c_put;
492 advance_conn_req_next(peer_device, req);
493 }
494
495 if (!(s & RQ_NET_DONE) && (set & RQ_NET_DONE)) {
496 if (s & RQ_NET_SENT)
497 atomic_sub(req->i.size >> 9, &device->ap_in_flight);
498 if (s & RQ_EXP_BARR_ACK)
499 kref_put(&req->kref, drbd_req_destroy);
500 req->net_done_jif = jiffies;
501
502 /* in ahead/behind mode, or just in case,
503 * before we finally destroy this request,
504 * the caching pointers must not reference it anymore */
505 advance_conn_req_next(peer_device, req);
506 advance_conn_req_ack_pending(peer_device, req);
507 advance_conn_req_not_net_done(peer_device, req);
508 }
509
510 /* potentially complete and destroy */
511
512 /* If we made progress, retry conflicting peer requests, if any. */
513 if (req->i.waiting)
514 wake_up(&device->misc_wait);
515
516 drbd_req_put_completion_ref(req, m, c_put);
517 kref_put(&req->kref, drbd_req_destroy);
518}
519
520static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req)
521{
522 if (!drbd_ratelimit())
523 return;
524
525 drbd_warn(device, "local %s IO error sector %llu+%u on %pg\n",
526 (req->rq_state & RQ_WRITE) ? "WRITE" : "READ",
527 (unsigned long long)req->i.sector,
528 req->i.size >> 9,
529 device->ldev->backing_bdev);
530}
531
532/* Helper for HANDED_OVER_TO_NETWORK.
533 * Is this a protocol A write (neither WRITE_ACK nor RECEIVE_ACK expected)?
534 * Is it also still "PENDING"?
535 * --> If so, clear PENDING and set NET_OK below.
536 * If it is a protocol A write, but not RQ_PENDING anymore, neg-ack was faster
537 * (and we must not set RQ_NET_OK) */
538static inline bool is_pending_write_protocol_A(struct drbd_request *req)
539{
540 return (req->rq_state &
541 (RQ_WRITE|RQ_NET_PENDING|RQ_EXP_WRITE_ACK|RQ_EXP_RECEIVE_ACK))
542 == (RQ_WRITE|RQ_NET_PENDING);
543}
544
545/* obviously this could be coded as many single functions
546 * instead of one huge switch,
547 * or by putting the code directly in the respective locations
548 * (as it has been before).
549 *
550 * but having it this way
551 * enforces that it is all in this one place, where it is easier to audit,
552 * it makes it obvious that whatever "event" "happens" to a request should
553 * happen "atomically" within the req_lock,
554 * and it enforces that we have to think in a very structured manner
555 * about the "events" that may happen to a request during its life time ...
556 *
557 *
558 * peer_device == NULL means local disk
559 */
560int __req_mod(struct drbd_request *req, enum drbd_req_event what,
561 struct drbd_peer_device *peer_device,
562 struct bio_and_error *m)
563{
564 struct drbd_device *const device = req->device;
565 struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL;
566 struct net_conf *nc;
567 int p, rv = 0;
568
569 if (m)
570 m->bio = NULL;
571
572 switch (what) {
573 default:
574 drbd_err(device, "LOGIC BUG in %s:%u\n", __FILE__ , __LINE__);
575 break;
576
577 /* does not happen...
578 * initialization done in drbd_req_new
579 case CREATED:
580 break;
581 */
582
583 case TO_BE_SENT: /* via network */
584 /* reached via __drbd_make_request
585 * and from w_read_retry_remote */
586 D_ASSERT(device, !(req->rq_state & RQ_NET_MASK));
587 rcu_read_lock();
588 nc = rcu_dereference(connection->net_conf);
589 p = nc->wire_protocol;
590 rcu_read_unlock();
591 req->rq_state |=
592 p == DRBD_PROT_C ? RQ_EXP_WRITE_ACK :
593 p == DRBD_PROT_B ? RQ_EXP_RECEIVE_ACK : 0;
594 mod_rq_state(req, m, 0, RQ_NET_PENDING);
595 break;
596
597 case TO_BE_SUBMITTED: /* locally */
598 /* reached via __drbd_make_request */
599 D_ASSERT(device, !(req->rq_state & RQ_LOCAL_MASK));
600 mod_rq_state(req, m, 0, RQ_LOCAL_PENDING);
601 break;
602
603 case COMPLETED_OK:
604 if (req->rq_state & RQ_WRITE)
605 device->writ_cnt += req->i.size >> 9;
606 else
607 device->read_cnt += req->i.size >> 9;
608
609 mod_rq_state(req, m, RQ_LOCAL_PENDING,
610 RQ_LOCAL_COMPLETED|RQ_LOCAL_OK);
611 break;
612
613 case ABORT_DISK_IO:
614 mod_rq_state(req, m, 0, RQ_LOCAL_ABORTED);
615 break;
616
617 case WRITE_COMPLETED_WITH_ERROR:
618 drbd_report_io_error(device, req);
619 __drbd_chk_io_error(device, DRBD_WRITE_ERROR);
620 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
621 break;
622
623 case READ_COMPLETED_WITH_ERROR:
624 drbd_set_out_of_sync(first_peer_device(device),
625 req->i.sector, req->i.size);
626 drbd_report_io_error(device, req);
627 __drbd_chk_io_error(device, DRBD_READ_ERROR);
628 fallthrough;
629 case READ_AHEAD_COMPLETED_WITH_ERROR:
630 /* it is legal to fail read-ahead, no __drbd_chk_io_error in that case. */
631 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
632 break;
633
634 case DISCARD_COMPLETED_NOTSUPP:
635 case DISCARD_COMPLETED_WITH_ERROR:
636 /* I'd rather not detach from local disk just because it
637 * failed a REQ_OP_DISCARD. */
638 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
639 break;
640
641 case QUEUE_FOR_NET_READ:
642 /* READ, and
643 * no local disk,
644 * or target area marked as invalid,
645 * or just got an io-error. */
646 /* from __drbd_make_request
647 * or from bio_endio during read io-error recovery */
648
649 /* So we can verify the handle in the answer packet.
650 * Corresponding drbd_remove_request_interval is in
651 * drbd_req_complete() */
652 D_ASSERT(device, drbd_interval_empty(&req->i));
653 drbd_insert_interval(&device->read_requests, &req->i);
654
655 set_bit(UNPLUG_REMOTE, &device->flags);
656
657 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
658 D_ASSERT(device, (req->rq_state & RQ_LOCAL_MASK) == 0);
659 mod_rq_state(req, m, 0, RQ_NET_QUEUED);
660 req->w.cb = w_send_read_req;
661 drbd_queue_work(&connection->sender_work,
662 &req->w);
663 break;
664
665 case QUEUE_FOR_NET_WRITE:
666 /* assert something? */
667 /* from __drbd_make_request only */
668
669 /* Corresponding drbd_remove_request_interval is in
670 * drbd_req_complete() */
671 D_ASSERT(device, drbd_interval_empty(&req->i));
672 drbd_insert_interval(&device->write_requests, &req->i);
673
674 /* NOTE
675 * In case the req ended up on the transfer log before being
676 * queued on the worker, it could lead to this request being
677 * missed during cleanup after connection loss.
678 * So we have to do both operations here,
679 * within the same lock that protects the transfer log.
680 *
681 * _req_add_to_epoch(req); this has to be after the
682 * _maybe_start_new_epoch(req); which happened in
683 * __drbd_make_request, because we now may set the bit
684 * again ourselves to close the current epoch.
685 *
686 * Add req to the (now) current epoch (barrier). */
687
688 /* otherwise we may lose an unplug, which may cause some remote
689 * io-scheduler timeout to expire, increasing maximum latency,
690 * hurting performance. */
691 set_bit(UNPLUG_REMOTE, &device->flags);
692
693 /* queue work item to send data */
694 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
695 mod_rq_state(req, m, 0, RQ_NET_QUEUED|RQ_EXP_BARR_ACK);
696 req->w.cb = w_send_dblock;
697 drbd_queue_work(&connection->sender_work,
698 &req->w);
699
700 /* close the epoch, in case it outgrew the limit */
701 rcu_read_lock();
702 nc = rcu_dereference(connection->net_conf);
703 p = nc->max_epoch_size;
704 rcu_read_unlock();
705 if (connection->current_tle_writes >= p)
706 start_new_tl_epoch(connection);
707
708 break;
709
710 case QUEUE_FOR_SEND_OOS:
711 mod_rq_state(req, m, 0, RQ_NET_QUEUED);
712 req->w.cb = w_send_out_of_sync;
713 drbd_queue_work(&connection->sender_work,
714 &req->w);
715 break;
716
717 case READ_RETRY_REMOTE_CANCELED:
718 case SEND_CANCELED:
719 case SEND_FAILED:
720 /* real cleanup will be done from tl_clear. just update flags
721 * so it is no longer marked as on the worker queue */
722 mod_rq_state(req, m, RQ_NET_QUEUED, 0);
723 break;
724
725 case HANDED_OVER_TO_NETWORK:
726 /* assert something? */
727 if (is_pending_write_protocol_A(req))
728 /* this is what is dangerous about protocol A:
729 * pretend it was successfully written on the peer. */
730 mod_rq_state(req, m, RQ_NET_QUEUED|RQ_NET_PENDING,
731 RQ_NET_SENT|RQ_NET_OK);
732 else
733 mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_SENT);
734 /* It is still not yet RQ_NET_DONE until the
735 * corresponding epoch barrier got acked as well,
736 * so we know what to dirty on connection loss. */
737 break;
738
739 case OOS_HANDED_TO_NETWORK:
740 /* Was not set PENDING, no longer QUEUED, so is now DONE
741 * as far as this connection is concerned. */
742 mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_DONE);
743 break;
744
745 case CONNECTION_LOST_WHILE_PENDING:
746 /* transfer log cleanup after connection loss */
747 mod_rq_state(req, m,
748 RQ_NET_OK|RQ_NET_PENDING|RQ_COMPLETION_SUSP,
749 RQ_NET_DONE);
750 break;
751
752 case CONFLICT_RESOLVED:
753 /* for superseded conflicting writes of multiple primaries,
754 * there is no need to keep anything in the tl, potential
755 * node crashes are covered by the activity log.
756 *
757 * If this request had been marked as RQ_POSTPONED before,
758 * it will actually not be completed, but "restarted",
759 * resubmitted from the retry worker context. */
760 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
761 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK);
762 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_DONE|RQ_NET_OK);
763 break;
764
765 case WRITE_ACKED_BY_PEER_AND_SIS:
766 req->rq_state |= RQ_NET_SIS;
767 fallthrough;
768 case WRITE_ACKED_BY_PEER:
769 /* Normal operation protocol C: successfully written on peer.
770 * During resync, even in protocol != C,
771 * we requested an explicit write ack anyways.
772 * Which means we cannot even assert anything here.
773 * Nothing more to do here.
774 * We want to keep the tl in place for all protocols, to cater
775 * for volatile write-back caches on lower level devices. */
776 goto ack_common;
777 case RECV_ACKED_BY_PEER:
778 D_ASSERT(device, req->rq_state & RQ_EXP_RECEIVE_ACK);
779 /* protocol B; pretends to be successfully written on peer.
780 * see also notes above in HANDED_OVER_TO_NETWORK about
781 * protocol != C */
782 ack_common:
783 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK);
784 break;
785
786 case POSTPONE_WRITE:
787 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK);
788 /* If this node has already detected the write conflict, the
789 * worker will be waiting on misc_wait. Wake it up once this
790 * request has completed locally.
791 */
792 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
793 req->rq_state |= RQ_POSTPONED;
794 if (req->i.waiting)
795 wake_up(&device->misc_wait);
796 /* Do not clear RQ_NET_PENDING. This request will make further
797 * progress via restart_conflicting_writes() or
798 * fail_postponed_requests(). Hopefully. */
799 break;
800
801 case NEG_ACKED:
802 mod_rq_state(req, m, RQ_NET_OK|RQ_NET_PENDING, 0);
803 break;
804
805 case FAIL_FROZEN_DISK_IO:
806 if (!(req->rq_state & RQ_LOCAL_COMPLETED))
807 break;
808 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0);
809 break;
810
811 case RESTART_FROZEN_DISK_IO:
812 if (!(req->rq_state & RQ_LOCAL_COMPLETED))
813 break;
814
815 mod_rq_state(req, m,
816 RQ_COMPLETION_SUSP|RQ_LOCAL_COMPLETED,
817 RQ_LOCAL_PENDING);
818
819 rv = MR_READ;
820 if (bio_data_dir(req->master_bio) == WRITE)
821 rv = MR_WRITE;
822
823 get_ldev(device); /* always succeeds in this call path */
824 req->w.cb = w_restart_disk_io;
825 drbd_queue_work(&connection->sender_work,
826 &req->w);
827 break;
828
829 case RESEND:
830 /* Simply complete (local only) READs. */
831 if (!(req->rq_state & RQ_WRITE) && !req->w.cb) {
832 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0);
833 break;
834 }
835
836 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK
837 before the connection loss (B&C only); only P_BARRIER_ACK
838 (or the local completion?) was missing when we suspended.
839 Throwing them out of the TL here by pretending we got a BARRIER_ACK.
840 During connection handshake, we ensure that the peer was not rebooted. */
841 if (!(req->rq_state & RQ_NET_OK)) {
842 /* FIXME could this possibly be a req->dw.cb == w_send_out_of_sync?
843 * in that case we must not set RQ_NET_PENDING. */
844
845 mod_rq_state(req, m, RQ_COMPLETION_SUSP, RQ_NET_QUEUED|RQ_NET_PENDING);
846 if (req->w.cb) {
847 /* w.cb expected to be w_send_dblock, or w_send_read_req */
848 drbd_queue_work(&connection->sender_work,
849 &req->w);
850 rv = req->rq_state & RQ_WRITE ? MR_WRITE : MR_READ;
851 } /* else: FIXME can this happen? */
852 break;
853 }
854 fallthrough; /* to BARRIER_ACKED */
855
856 case BARRIER_ACKED:
857 /* barrier ack for READ requests does not make sense */
858 if (!(req->rq_state & RQ_WRITE))
859 break;
860
861 if (req->rq_state & RQ_NET_PENDING) {
862 /* barrier came in before all requests were acked.
863 * this is bad, because if the connection is lost now,
864 * we won't be able to clean them up... */
865 drbd_err(device, "FIXME (BARRIER_ACKED but pending)\n");
866 }
867 /* Allowed to complete requests, even while suspended.
868 * As this is called for all requests within a matching epoch,
869 * we need to filter, and only set RQ_NET_DONE for those that
870 * have actually been on the wire. */
871 mod_rq_state(req, m, RQ_COMPLETION_SUSP,
872 (req->rq_state & RQ_NET_MASK) ? RQ_NET_DONE : 0);
873 break;
874
875 case DATA_RECEIVED:
876 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
877 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE);
878 break;
879
880 case QUEUE_AS_DRBD_BARRIER:
881 start_new_tl_epoch(connection);
882 mod_rq_state(req, m, 0, RQ_NET_OK|RQ_NET_DONE);
883 break;
884 }
885
886 return rv;
887}
888
889/* we may do a local read if:
890 * - we are consistent (of course),
891 * - or we are generally inconsistent,
892 * BUT we are still/already IN SYNC for this area.
893 * since size may be bigger than BM_BLOCK_SIZE,
894 * we may need to check several bits.
895 */
896static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size)
897{
898 unsigned long sbnr, ebnr;
899 sector_t esector, nr_sectors;
900
901 if (device->state.disk == D_UP_TO_DATE)
902 return true;
903 if (device->state.disk != D_INCONSISTENT)
904 return false;
905 esector = sector + (size >> 9) - 1;
906 nr_sectors = get_capacity(device->vdisk);
907 D_ASSERT(device, sector < nr_sectors);
908 D_ASSERT(device, esector < nr_sectors);
909
910 sbnr = BM_SECT_TO_BIT(sector);
911 ebnr = BM_SECT_TO_BIT(esector);
912
913 return drbd_bm_count_bits(device, sbnr, ebnr) == 0;
914}
915
916static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t sector,
917 enum drbd_read_balancing rbm)
918{
919 int stripe_shift;
920
921 switch (rbm) {
922 case RB_CONGESTED_REMOTE:
923 return false;
924 case RB_LEAST_PENDING:
925 return atomic_read(&device->local_cnt) >
926 atomic_read(&device->ap_pending_cnt) + atomic_read(&device->rs_pending_cnt);
927 case RB_32K_STRIPING: /* stripe_shift = 15 */
928 case RB_64K_STRIPING:
929 case RB_128K_STRIPING:
930 case RB_256K_STRIPING:
931 case RB_512K_STRIPING:
932 case RB_1M_STRIPING: /* stripe_shift = 20 */
933 stripe_shift = (rbm - RB_32K_STRIPING + 15);
934 return (sector >> (stripe_shift - 9)) & 1;
935 case RB_ROUND_ROBIN:
936 return test_and_change_bit(READ_BALANCE_RR, &device->flags);
937 case RB_PREFER_REMOTE:
938 return true;
939 case RB_PREFER_LOCAL:
940 default:
941 return false;
942 }
943}
944
945/*
946 * complete_conflicting_writes - wait for any conflicting write requests
947 *
948 * The write_requests tree contains all active write requests which we
949 * currently know about. Wait for any requests to complete which conflict with
950 * the new one.
951 *
952 * Only way out: remove the conflicting intervals from the tree.
953 */
954static void complete_conflicting_writes(struct drbd_request *req)
955{
956 DEFINE_WAIT(wait);
957 struct drbd_device *device = req->device;
958 struct drbd_interval *i;
959 sector_t sector = req->i.sector;
960 int size = req->i.size;
961
962 for (;;) {
963 drbd_for_each_overlap(i, &device->write_requests, sector, size) {
964 /* Ignore, if already completed to upper layers. */
965 if (i->completed)
966 continue;
967 /* Handle the first found overlap. After the schedule
968 * we have to restart the tree walk. */
969 break;
970 }
971 if (!i) /* if any */
972 break;
973
974 /* Indicate to wake up device->misc_wait on progress. */
975 prepare_to_wait(&device->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
976 i->waiting = true;
977 spin_unlock_irq(&device->resource->req_lock);
978 schedule();
979 spin_lock_irq(&device->resource->req_lock);
980 }
981 finish_wait(&device->misc_wait, &wait);
982}
983
984/* called within req_lock */
985static void maybe_pull_ahead(struct drbd_device *device)
986{
987 struct drbd_connection *connection = first_peer_device(device)->connection;
988 struct net_conf *nc;
989 bool congested = false;
990 enum drbd_on_congestion on_congestion;
991
992 rcu_read_lock();
993 nc = rcu_dereference(connection->net_conf);
994 on_congestion = nc ? nc->on_congestion : OC_BLOCK;
995 rcu_read_unlock();
996 if (on_congestion == OC_BLOCK ||
997 connection->agreed_pro_version < 96)
998 return;
999
1000 if (on_congestion == OC_PULL_AHEAD && device->state.conn == C_AHEAD)
1001 return; /* nothing to do ... */
1002
1003 /* If I don't even have good local storage, we can not reasonably try
1004 * to pull ahead of the peer. We also need the local reference to make
1005 * sure device->act_log is there.
1006 */
1007 if (!get_ldev_if_state(device, D_UP_TO_DATE))
1008 return;
1009
1010 if (nc->cong_fill &&
1011 atomic_read(&device->ap_in_flight) >= nc->cong_fill) {
1012 drbd_info(device, "Congestion-fill threshold reached\n");
1013 congested = true;
1014 }
1015
1016 if (device->act_log->used >= nc->cong_extents) {
1017 drbd_info(device, "Congestion-extents threshold reached\n");
1018 congested = true;
1019 }
1020
1021 if (congested) {
1022 /* start a new epoch for non-mirrored writes */
1023 start_new_tl_epoch(first_peer_device(device)->connection);
1024
1025 if (on_congestion == OC_PULL_AHEAD)
1026 _drbd_set_state(_NS(device, conn, C_AHEAD), 0, NULL);
1027 else /*nc->on_congestion == OC_DISCONNECT */
1028 _drbd_set_state(_NS(device, conn, C_DISCONNECTING), 0, NULL);
1029 }
1030 put_ldev(device);
1031}
1032
1033/* If this returns false, and req->private_bio is still set,
1034 * this should be submitted locally.
1035 *
1036 * If it returns false, but req->private_bio is not set,
1037 * we do not have access to good data :(
1038 *
1039 * Otherwise, this destroys req->private_bio, if any,
1040 * and returns true.
1041 */
1042static bool do_remote_read(struct drbd_request *req)
1043{
1044 struct drbd_device *device = req->device;
1045 enum drbd_read_balancing rbm;
1046
1047 if (req->private_bio) {
1048 if (!drbd_may_do_local_read(device,
1049 req->i.sector, req->i.size)) {
1050 bio_put(req->private_bio);
1051 req->private_bio = NULL;
1052 put_ldev(device);
1053 }
1054 }
1055
1056 if (device->state.pdsk != D_UP_TO_DATE)
1057 return false;
1058
1059 if (req->private_bio == NULL)
1060 return true;
1061
1062 /* TODO: improve read balancing decisions, take into account drbd
1063 * protocol, pending requests etc. */
1064
1065 rcu_read_lock();
1066 rbm = rcu_dereference(device->ldev->disk_conf)->read_balancing;
1067 rcu_read_unlock();
1068
1069 if (rbm == RB_PREFER_LOCAL && req->private_bio)
1070 return false; /* submit locally */
1071
1072 if (remote_due_to_read_balancing(device, req->i.sector, rbm)) {
1073 if (req->private_bio) {
1074 bio_put(req->private_bio);
1075 req->private_bio = NULL;
1076 put_ldev(device);
1077 }
1078 return true;
1079 }
1080
1081 return false;
1082}
1083
1084bool drbd_should_do_remote(union drbd_dev_state s)
1085{
1086 return s.pdsk == D_UP_TO_DATE ||
1087 (s.pdsk >= D_INCONSISTENT &&
1088 s.conn >= C_WF_BITMAP_T &&
1089 s.conn < C_AHEAD);
1090 /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T.
1091 That is equivalent since before 96 IO was frozen in the C_WF_BITMAP*
1092 states. */
1093}
1094
1095static bool drbd_should_send_out_of_sync(union drbd_dev_state s)
1096{
1097 return s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S;
1098 /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary
1099 since we enter state C_AHEAD only if proto >= 96 */
1100}
1101
1102/* returns number of connections (== 1, for drbd 8.4)
1103 * expected to actually write this data,
1104 * which does NOT include those that we are L_AHEAD for. */
1105static int drbd_process_write_request(struct drbd_request *req)
1106{
1107 struct drbd_device *device = req->device;
1108 struct drbd_peer_device *peer_device = first_peer_device(device);
1109 int remote, send_oos;
1110
1111 remote = drbd_should_do_remote(device->state);
1112 send_oos = drbd_should_send_out_of_sync(device->state);
1113
1114 /* Need to replicate writes. Unless it is an empty flush,
1115 * which is better mapped to a DRBD P_BARRIER packet,
1116 * also for drbd wire protocol compatibility reasons.
1117 * If this was a flush, just start a new epoch.
1118 * Unless the current epoch was empty anyways, or we are not currently
1119 * replicating, in which case there is no point. */
1120 if (unlikely(req->i.size == 0)) {
1121 /* The only size==0 bios we expect are empty flushes. */
1122 D_ASSERT(device, req->master_bio->bi_opf & REQ_PREFLUSH);
1123 if (remote)
1124 _req_mod(req, QUEUE_AS_DRBD_BARRIER, peer_device);
1125 return remote;
1126 }
1127
1128 if (!remote && !send_oos)
1129 return 0;
1130
1131 D_ASSERT(device, !(remote && send_oos));
1132
1133 if (remote) {
1134 _req_mod(req, TO_BE_SENT, peer_device);
1135 _req_mod(req, QUEUE_FOR_NET_WRITE, peer_device);
1136 } else if (drbd_set_out_of_sync(peer_device, req->i.sector, req->i.size))
1137 _req_mod(req, QUEUE_FOR_SEND_OOS, peer_device);
1138
1139 return remote;
1140}
1141
1142static void drbd_process_discard_or_zeroes_req(struct drbd_request *req, int flags)
1143{
1144 int err = drbd_issue_discard_or_zero_out(req->device,
1145 req->i.sector, req->i.size >> 9, flags);
1146 if (err)
1147 req->private_bio->bi_status = BLK_STS_IOERR;
1148 bio_endio(req->private_bio);
1149}
1150
1151static void
1152drbd_submit_req_private_bio(struct drbd_request *req)
1153{
1154 struct drbd_device *device = req->device;
1155 struct bio *bio = req->private_bio;
1156 unsigned int type;
1157
1158 if (bio_op(bio) != REQ_OP_READ)
1159 type = DRBD_FAULT_DT_WR;
1160 else if (bio->bi_opf & REQ_RAHEAD)
1161 type = DRBD_FAULT_DT_RA;
1162 else
1163 type = DRBD_FAULT_DT_RD;
1164
1165 /* State may have changed since we grabbed our reference on the
1166 * ->ldev member. Double check, and short-circuit to endio.
1167 * In case the last activity log transaction failed to get on
1168 * stable storage, and this is a WRITE, we may not even submit
1169 * this bio. */
1170 if (get_ldev(device)) {
1171 if (drbd_insert_fault(device, type))
1172 bio_io_error(bio);
1173 else if (bio_op(bio) == REQ_OP_WRITE_ZEROES)
1174 drbd_process_discard_or_zeroes_req(req, EE_ZEROOUT |
1175 ((bio->bi_opf & REQ_NOUNMAP) ? 0 : EE_TRIM));
1176 else if (bio_op(bio) == REQ_OP_DISCARD)
1177 drbd_process_discard_or_zeroes_req(req, EE_TRIM);
1178 else
1179 submit_bio_noacct(bio);
1180 put_ldev(device);
1181 } else
1182 bio_io_error(bio);
1183}
1184
1185static void drbd_queue_write(struct drbd_device *device, struct drbd_request *req)
1186{
1187 spin_lock_irq(&device->resource->req_lock);
1188 list_add_tail(&req->tl_requests, &device->submit.writes);
1189 list_add_tail(&req->req_pending_master_completion,
1190 &device->pending_master_completion[1 /* WRITE */]);
1191 spin_unlock_irq(&device->resource->req_lock);
1192 queue_work(device->submit.wq, &device->submit.worker);
1193 /* do_submit() may sleep internally on al_wait, too */
1194 wake_up(&device->al_wait);
1195}
1196
1197/* returns the new drbd_request pointer, if the caller is expected to
1198 * drbd_send_and_submit() it (to save latency), or NULL if we queued the
1199 * request on the submitter thread.
1200 * Returns ERR_PTR(-ENOMEM) if we cannot allocate a drbd_request.
1201 */
1202static struct drbd_request *
1203drbd_request_prepare(struct drbd_device *device, struct bio *bio)
1204{
1205 const int rw = bio_data_dir(bio);
1206 struct drbd_request *req;
1207
1208 /* allocate outside of all locks; */
1209 req = drbd_req_new(device, bio);
1210 if (!req) {
1211 dec_ap_bio(device);
1212 /* only pass the error to the upper layers.
1213 * if user cannot handle io errors, that's not our business. */
1214 drbd_err(device, "could not kmalloc() req\n");
1215 bio->bi_status = BLK_STS_RESOURCE;
1216 bio_endio(bio);
1217 return ERR_PTR(-ENOMEM);
1218 }
1219
1220 /* Update disk stats */
1221 req->start_jif = bio_start_io_acct(req->master_bio);
1222
1223 if (get_ldev(device)) {
1224 req->private_bio = bio_alloc_clone(device->ldev->backing_bdev,
1225 bio, GFP_NOIO,
1226 &drbd_io_bio_set);
1227 req->private_bio->bi_private = req;
1228 req->private_bio->bi_end_io = drbd_request_endio;
1229 }
1230
1231 /* process discards always from our submitter thread */
1232 if (bio_op(bio) == REQ_OP_WRITE_ZEROES ||
1233 bio_op(bio) == REQ_OP_DISCARD)
1234 goto queue_for_submitter_thread;
1235
1236 if (rw == WRITE && req->private_bio && req->i.size
1237 && !test_bit(AL_SUSPENDED, &device->flags)) {
1238 if (!drbd_al_begin_io_fastpath(device, &req->i))
1239 goto queue_for_submitter_thread;
1240 req->rq_state |= RQ_IN_ACT_LOG;
1241 req->in_actlog_jif = jiffies;
1242 }
1243 return req;
1244
1245 queue_for_submitter_thread:
1246 atomic_inc(&device->ap_actlog_cnt);
1247 drbd_queue_write(device, req);
1248 return NULL;
1249}
1250
1251/* Require at least one path to current data.
1252 * We don't want to allow writes on C_STANDALONE D_INCONSISTENT:
1253 * We would not allow to read what was written,
1254 * we would not have bumped the data generation uuids,
1255 * we would cause data divergence for all the wrong reasons.
1256 *
1257 * If we don't see at least one D_UP_TO_DATE, we will fail this request,
1258 * which either returns EIO, or, if OND_SUSPEND_IO is set, suspends IO,
1259 * and queues for retry later.
1260 */
1261static bool may_do_writes(struct drbd_device *device)
1262{
1263 const union drbd_dev_state s = device->state;
1264 return s.disk == D_UP_TO_DATE || s.pdsk == D_UP_TO_DATE;
1265}
1266
1267struct drbd_plug_cb {
1268 struct blk_plug_cb cb;
1269 struct drbd_request *most_recent_req;
1270 /* do we need more? */
1271};
1272
1273static void drbd_unplug(struct blk_plug_cb *cb, bool from_schedule)
1274{
1275 struct drbd_plug_cb *plug = container_of(cb, struct drbd_plug_cb, cb);
1276 struct drbd_resource *resource = plug->cb.data;
1277 struct drbd_request *req = plug->most_recent_req;
1278
1279 kfree(cb);
1280 if (!req)
1281 return;
1282
1283 spin_lock_irq(&resource->req_lock);
1284 /* In case the sender did not process it yet, raise the flag to
1285 * have it followed with P_UNPLUG_REMOTE just after. */
1286 req->rq_state |= RQ_UNPLUG;
1287 /* but also queue a generic unplug */
1288 drbd_queue_unplug(req->device);
1289 kref_put(&req->kref, drbd_req_destroy);
1290 spin_unlock_irq(&resource->req_lock);
1291}
1292
1293static struct drbd_plug_cb* drbd_check_plugged(struct drbd_resource *resource)
1294{
1295 /* A lot of text to say
1296 * return (struct drbd_plug_cb*)blk_check_plugged(); */
1297 struct drbd_plug_cb *plug;
1298 struct blk_plug_cb *cb = blk_check_plugged(drbd_unplug, resource, sizeof(*plug));
1299
1300 if (cb)
1301 plug = container_of(cb, struct drbd_plug_cb, cb);
1302 else
1303 plug = NULL;
1304 return plug;
1305}
1306
1307static void drbd_update_plug(struct drbd_plug_cb *plug, struct drbd_request *req)
1308{
1309 struct drbd_request *tmp = plug->most_recent_req;
1310 /* Will be sent to some peer.
1311 * Remember to tag it with UNPLUG_REMOTE on unplug */
1312 kref_get(&req->kref);
1313 plug->most_recent_req = req;
1314 if (tmp)
1315 kref_put(&tmp->kref, drbd_req_destroy);
1316}
1317
1318static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request *req)
1319{
1320 struct drbd_resource *resource = device->resource;
1321 struct drbd_peer_device *peer_device = first_peer_device(device);
1322 const int rw = bio_data_dir(req->master_bio);
1323 struct bio_and_error m = { NULL, };
1324 bool no_remote = false;
1325 bool submit_private_bio = false;
1326
1327 spin_lock_irq(&resource->req_lock);
1328 if (rw == WRITE) {
1329 /* This may temporarily give up the req_lock,
1330 * but will re-aquire it before it returns here.
1331 * Needs to be before the check on drbd_suspended() */
1332 complete_conflicting_writes(req);
1333 /* no more giving up req_lock from now on! */
1334
1335 /* check for congestion, and potentially stop sending
1336 * full data updates, but start sending "dirty bits" only. */
1337 maybe_pull_ahead(device);
1338 }
1339
1340
1341 if (drbd_suspended(device)) {
1342 /* push back and retry: */
1343 req->rq_state |= RQ_POSTPONED;
1344 if (req->private_bio) {
1345 bio_put(req->private_bio);
1346 req->private_bio = NULL;
1347 put_ldev(device);
1348 }
1349 goto out;
1350 }
1351
1352 /* We fail READ early, if we can not serve it.
1353 * We must do this before req is registered on any lists.
1354 * Otherwise, drbd_req_complete() will queue failed READ for retry. */
1355 if (rw != WRITE) {
1356 if (!do_remote_read(req) && !req->private_bio)
1357 goto nodata;
1358 }
1359
1360 /* which transfer log epoch does this belong to? */
1361 req->epoch = atomic_read(&first_peer_device(device)->connection->current_tle_nr);
1362
1363 /* no point in adding empty flushes to the transfer log,
1364 * they are mapped to drbd barriers already. */
1365 if (likely(req->i.size!=0)) {
1366 if (rw == WRITE)
1367 first_peer_device(device)->connection->current_tle_writes++;
1368
1369 list_add_tail(&req->tl_requests, &first_peer_device(device)->connection->transfer_log);
1370 }
1371
1372 if (rw == WRITE) {
1373 if (req->private_bio && !may_do_writes(device)) {
1374 bio_put(req->private_bio);
1375 req->private_bio = NULL;
1376 put_ldev(device);
1377 goto nodata;
1378 }
1379 if (!drbd_process_write_request(req))
1380 no_remote = true;
1381 } else {
1382 /* We either have a private_bio, or we can read from remote.
1383 * Otherwise we had done the goto nodata above. */
1384 if (req->private_bio == NULL) {
1385 _req_mod(req, TO_BE_SENT, peer_device);
1386 _req_mod(req, QUEUE_FOR_NET_READ, peer_device);
1387 } else
1388 no_remote = true;
1389 }
1390
1391 if (no_remote == false) {
1392 struct drbd_plug_cb *plug = drbd_check_plugged(resource);
1393 if (plug)
1394 drbd_update_plug(plug, req);
1395 }
1396
1397 /* If it took the fast path in drbd_request_prepare, add it here.
1398 * The slow path has added it already. */
1399 if (list_empty(&req->req_pending_master_completion))
1400 list_add_tail(&req->req_pending_master_completion,
1401 &device->pending_master_completion[rw == WRITE]);
1402 if (req->private_bio) {
1403 /* needs to be marked within the same spinlock */
1404 req->pre_submit_jif = jiffies;
1405 list_add_tail(&req->req_pending_local,
1406 &device->pending_completion[rw == WRITE]);
1407 _req_mod(req, TO_BE_SUBMITTED, NULL);
1408 /* but we need to give up the spinlock to submit */
1409 submit_private_bio = true;
1410 } else if (no_remote) {
1411nodata:
1412 if (drbd_ratelimit())
1413 drbd_err(device, "IO ERROR: neither local nor remote data, sector %llu+%u\n",
1414 (unsigned long long)req->i.sector, req->i.size >> 9);
1415 /* A write may have been queued for send_oos, however.
1416 * So we can not simply free it, we must go through drbd_req_put_completion_ref() */
1417 }
1418
1419out:
1420 drbd_req_put_completion_ref(req, &m, 1);
1421 spin_unlock_irq(&resource->req_lock);
1422
1423 /* Even though above is a kref_put(), this is safe.
1424 * As long as we still need to submit our private bio,
1425 * we hold a completion ref, and the request cannot disappear.
1426 * If however this request did not even have a private bio to submit
1427 * (e.g. remote read), req may already be invalid now.
1428 * That's why we cannot check on req->private_bio. */
1429 if (submit_private_bio)
1430 drbd_submit_req_private_bio(req);
1431 if (m.bio)
1432 complete_master_bio(device, &m);
1433}
1434
1435void __drbd_make_request(struct drbd_device *device, struct bio *bio)
1436{
1437 struct drbd_request *req = drbd_request_prepare(device, bio);
1438 if (IS_ERR_OR_NULL(req))
1439 return;
1440 drbd_send_and_submit(device, req);
1441}
1442
1443static void submit_fast_path(struct drbd_device *device, struct list_head *incoming)
1444{
1445 struct blk_plug plug;
1446 struct drbd_request *req, *tmp;
1447
1448 blk_start_plug(&plug);
1449 list_for_each_entry_safe(req, tmp, incoming, tl_requests) {
1450 const int rw = bio_data_dir(req->master_bio);
1451
1452 if (rw == WRITE /* rw != WRITE should not even end up here! */
1453 && req->private_bio && req->i.size
1454 && !test_bit(AL_SUSPENDED, &device->flags)) {
1455 if (!drbd_al_begin_io_fastpath(device, &req->i))
1456 continue;
1457
1458 req->rq_state |= RQ_IN_ACT_LOG;
1459 req->in_actlog_jif = jiffies;
1460 atomic_dec(&device->ap_actlog_cnt);
1461 }
1462
1463 list_del_init(&req->tl_requests);
1464 drbd_send_and_submit(device, req);
1465 }
1466 blk_finish_plug(&plug);
1467}
1468
1469static bool prepare_al_transaction_nonblock(struct drbd_device *device,
1470 struct list_head *incoming,
1471 struct list_head *pending,
1472 struct list_head *later)
1473{
1474 struct drbd_request *req;
1475 int wake = 0;
1476 int err;
1477
1478 spin_lock_irq(&device->al_lock);
1479 while ((req = list_first_entry_or_null(incoming, struct drbd_request, tl_requests))) {
1480 err = drbd_al_begin_io_nonblock(device, &req->i);
1481 if (err == -ENOBUFS)
1482 break;
1483 if (err == -EBUSY)
1484 wake = 1;
1485 if (err)
1486 list_move_tail(&req->tl_requests, later);
1487 else
1488 list_move_tail(&req->tl_requests, pending);
1489 }
1490 spin_unlock_irq(&device->al_lock);
1491 if (wake)
1492 wake_up(&device->al_wait);
1493 return !list_empty(pending);
1494}
1495
1496static void send_and_submit_pending(struct drbd_device *device, struct list_head *pending)
1497{
1498 struct blk_plug plug;
1499 struct drbd_request *req;
1500
1501 blk_start_plug(&plug);
1502 while ((req = list_first_entry_or_null(pending, struct drbd_request, tl_requests))) {
1503 req->rq_state |= RQ_IN_ACT_LOG;
1504 req->in_actlog_jif = jiffies;
1505 atomic_dec(&device->ap_actlog_cnt);
1506 list_del_init(&req->tl_requests);
1507 drbd_send_and_submit(device, req);
1508 }
1509 blk_finish_plug(&plug);
1510}
1511
1512void do_submit(struct work_struct *ws)
1513{
1514 struct drbd_device *device = container_of(ws, struct drbd_device, submit.worker);
1515 LIST_HEAD(incoming); /* from drbd_make_request() */
1516 LIST_HEAD(pending); /* to be submitted after next AL-transaction commit */
1517 LIST_HEAD(busy); /* blocked by resync requests */
1518
1519 /* grab new incoming requests */
1520 spin_lock_irq(&device->resource->req_lock);
1521 list_splice_tail_init(&device->submit.writes, &incoming);
1522 spin_unlock_irq(&device->resource->req_lock);
1523
1524 for (;;) {
1525 DEFINE_WAIT(wait);
1526
1527 /* move used-to-be-busy back to front of incoming */
1528 list_splice_init(&busy, &incoming);
1529 submit_fast_path(device, &incoming);
1530 if (list_empty(&incoming))
1531 break;
1532
1533 for (;;) {
1534 prepare_to_wait(&device->al_wait, &wait, TASK_UNINTERRUPTIBLE);
1535
1536 list_splice_init(&busy, &incoming);
1537 prepare_al_transaction_nonblock(device, &incoming, &pending, &busy);
1538 if (!list_empty(&pending))
1539 break;
1540
1541 schedule();
1542
1543 /* If all currently "hot" activity log extents are kept busy by
1544 * incoming requests, we still must not totally starve new
1545 * requests to "cold" extents.
1546 * Something left on &incoming means there had not been
1547 * enough update slots available, and the activity log
1548 * has been marked as "starving".
1549 *
1550 * Try again now, without looking for new requests,
1551 * effectively blocking all new requests until we made
1552 * at least _some_ progress with what we currently have.
1553 */
1554 if (!list_empty(&incoming))
1555 continue;
1556
1557 /* Nothing moved to pending, but nothing left
1558 * on incoming: all moved to busy!
1559 * Grab new and iterate. */
1560 spin_lock_irq(&device->resource->req_lock);
1561 list_splice_tail_init(&device->submit.writes, &incoming);
1562 spin_unlock_irq(&device->resource->req_lock);
1563 }
1564 finish_wait(&device->al_wait, &wait);
1565
1566 /* If the transaction was full, before all incoming requests
1567 * had been processed, skip ahead to commit, and iterate
1568 * without splicing in more incoming requests from upper layers.
1569 *
1570 * Else, if all incoming have been processed,
1571 * they have become either "pending" (to be submitted after
1572 * next transaction commit) or "busy" (blocked by resync).
1573 *
1574 * Maybe more was queued, while we prepared the transaction?
1575 * Try to stuff those into this transaction as well.
1576 * Be strictly non-blocking here,
1577 * we already have something to commit.
1578 *
1579 * Commit if we don't make any more progres.
1580 */
1581
1582 while (list_empty(&incoming)) {
1583 LIST_HEAD(more_pending);
1584 LIST_HEAD(more_incoming);
1585 bool made_progress;
1586
1587 /* It is ok to look outside the lock,
1588 * it's only an optimization anyways */
1589 if (list_empty(&device->submit.writes))
1590 break;
1591
1592 spin_lock_irq(&device->resource->req_lock);
1593 list_splice_tail_init(&device->submit.writes, &more_incoming);
1594 spin_unlock_irq(&device->resource->req_lock);
1595
1596 if (list_empty(&more_incoming))
1597 break;
1598
1599 made_progress = prepare_al_transaction_nonblock(device, &more_incoming, &more_pending, &busy);
1600
1601 list_splice_tail_init(&more_pending, &pending);
1602 list_splice_tail_init(&more_incoming, &incoming);
1603 if (!made_progress)
1604 break;
1605 }
1606
1607 drbd_al_begin_io_commit(device);
1608 send_and_submit_pending(device, &pending);
1609 }
1610}
1611
1612void drbd_submit_bio(struct bio *bio)
1613{
1614 struct drbd_device *device = bio->bi_bdev->bd_disk->private_data;
1615
1616 bio = bio_split_to_limits(bio);
1617 if (!bio)
1618 return;
1619
1620 /*
1621 * what we "blindly" assume:
1622 */
1623 D_ASSERT(device, IS_ALIGNED(bio->bi_iter.bi_size, 512));
1624
1625 inc_ap_bio(device);
1626 __drbd_make_request(device, bio);
1627}
1628
1629static bool net_timeout_reached(struct drbd_request *net_req,
1630 struct drbd_connection *connection,
1631 unsigned long now, unsigned long ent,
1632 unsigned int ko_count, unsigned int timeout)
1633{
1634 struct drbd_device *device = net_req->device;
1635
1636 if (!time_after(now, net_req->pre_send_jif + ent))
1637 return false;
1638
1639 if (time_in_range(now, connection->last_reconnect_jif, connection->last_reconnect_jif + ent))
1640 return false;
1641
1642 if (net_req->rq_state & RQ_NET_PENDING) {
1643 drbd_warn(device, "Remote failed to finish a request within %ums > ko-count (%u) * timeout (%u * 0.1s)\n",
1644 jiffies_to_msecs(now - net_req->pre_send_jif), ko_count, timeout);
1645 return true;
1646 }
1647
1648 /* We received an ACK already (or are using protocol A),
1649 * but are waiting for the epoch closing barrier ack.
1650 * Check if we sent the barrier already. We should not blame the peer
1651 * for being unresponsive, if we did not even ask it yet. */
1652 if (net_req->epoch == connection->send.current_epoch_nr) {
1653 drbd_warn(device,
1654 "We did not send a P_BARRIER for %ums > ko-count (%u) * timeout (%u * 0.1s); drbd kernel thread blocked?\n",
1655 jiffies_to_msecs(now - net_req->pre_send_jif), ko_count, timeout);
1656 return false;
1657 }
1658
1659 /* Worst case: we may have been blocked for whatever reason, then
1660 * suddenly are able to send a lot of requests (and epoch separating
1661 * barriers) in quick succession.
1662 * The timestamp of the net_req may be much too old and not correspond
1663 * to the sending time of the relevant unack'ed barrier packet, so
1664 * would trigger a spurious timeout. The latest barrier packet may
1665 * have a too recent timestamp to trigger the timeout, potentially miss
1666 * a timeout. Right now we don't have a place to conveniently store
1667 * these timestamps.
1668 * But in this particular situation, the application requests are still
1669 * completed to upper layers, DRBD should still "feel" responsive.
1670 * No need yet to kill this connection, it may still recover.
1671 * If not, eventually we will have queued enough into the network for
1672 * us to block. From that point of view, the timestamp of the last sent
1673 * barrier packet is relevant enough.
1674 */
1675 if (time_after(now, connection->send.last_sent_barrier_jif + ent)) {
1676 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",
1677 connection->send.last_sent_barrier_jif, now,
1678 jiffies_to_msecs(now - connection->send.last_sent_barrier_jif), ko_count, timeout);
1679 return true;
1680 }
1681 return false;
1682}
1683
1684/* A request is considered timed out, if
1685 * - we have some effective timeout from the configuration,
1686 * with some state restrictions applied,
1687 * - the oldest request is waiting for a response from the network
1688 * resp. the local disk,
1689 * - the oldest request is in fact older than the effective timeout,
1690 * - the connection was established (resp. disk was attached)
1691 * for longer than the timeout already.
1692 * Note that for 32bit jiffies and very stable connections/disks,
1693 * we may have a wrap around, which is catched by
1694 * !time_in_range(now, last_..._jif, last_..._jif + timeout).
1695 *
1696 * Side effect: once per 32bit wrap-around interval, which means every
1697 * ~198 days with 250 HZ, we have a window where the timeout would need
1698 * to expire twice (worst case) to become effective. Good enough.
1699 */
1700
1701void request_timer_fn(struct timer_list *t)
1702{
1703 struct drbd_device *device = timer_container_of(device, t,
1704 request_timer);
1705 struct drbd_connection *connection = first_peer_device(device)->connection;
1706 struct drbd_request *req_read, *req_write, *req_peer; /* oldest request */
1707 struct net_conf *nc;
1708 unsigned long oldest_submit_jif;
1709 unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */
1710 unsigned long now;
1711 unsigned int ko_count = 0, timeout = 0;
1712
1713 rcu_read_lock();
1714 nc = rcu_dereference(connection->net_conf);
1715 if (nc && device->state.conn >= C_WF_REPORT_PARAMS) {
1716 ko_count = nc->ko_count;
1717 timeout = nc->timeout;
1718 }
1719
1720 if (get_ldev(device)) { /* implicit state.disk >= D_INCONSISTENT */
1721 dt = rcu_dereference(device->ldev->disk_conf)->disk_timeout * HZ / 10;
1722 put_ldev(device);
1723 }
1724 rcu_read_unlock();
1725
1726
1727 ent = timeout * HZ/10 * ko_count;
1728 et = min_not_zero(dt, ent);
1729
1730 if (!et)
1731 return; /* Recurring timer stopped */
1732
1733 now = jiffies;
1734 nt = now + et;
1735
1736 spin_lock_irq(&device->resource->req_lock);
1737 req_read = list_first_entry_or_null(&device->pending_completion[0], struct drbd_request, req_pending_local);
1738 req_write = list_first_entry_or_null(&device->pending_completion[1], struct drbd_request, req_pending_local);
1739
1740 /* maybe the oldest request waiting for the peer is in fact still
1741 * blocking in tcp sendmsg. That's ok, though, that's handled via the
1742 * socket send timeout, requesting a ping, and bumping ko-count in
1743 * we_should_drop_the_connection().
1744 */
1745
1746 /* check the oldest request we did successfully sent,
1747 * but which is still waiting for an ACK. */
1748 req_peer = connection->req_ack_pending;
1749
1750 /* if we don't have such request (e.g. protocoll A)
1751 * check the oldest requests which is still waiting on its epoch
1752 * closing barrier ack. */
1753 if (!req_peer)
1754 req_peer = connection->req_not_net_done;
1755
1756 /* evaluate the oldest peer request only in one timer! */
1757 if (req_peer && req_peer->device != device)
1758 req_peer = NULL;
1759
1760 /* do we have something to evaluate? */
1761 if (req_peer == NULL && req_write == NULL && req_read == NULL)
1762 goto out;
1763
1764 oldest_submit_jif =
1765 (req_write && req_read)
1766 ? ( time_before(req_write->pre_submit_jif, req_read->pre_submit_jif)
1767 ? req_write->pre_submit_jif : req_read->pre_submit_jif )
1768 : req_write ? req_write->pre_submit_jif
1769 : req_read ? req_read->pre_submit_jif : now;
1770
1771 if (ent && req_peer && net_timeout_reached(req_peer, connection, now, ent, ko_count, timeout))
1772 _conn_request_state(connection, NS(conn, C_TIMEOUT), CS_VERBOSE | CS_HARD);
1773
1774 if (dt && oldest_submit_jif != now &&
1775 time_after(now, oldest_submit_jif + dt) &&
1776 !time_in_range(now, device->last_reattach_jif, device->last_reattach_jif + dt)) {
1777 drbd_warn(device, "Local backing device failed to meet the disk-timeout\n");
1778 __drbd_chk_io_error(device, DRBD_FORCE_DETACH);
1779 }
1780
1781 /* Reschedule timer for the nearest not already expired timeout.
1782 * Fallback to now + min(effective network timeout, disk timeout). */
1783 ent = (ent && req_peer && time_before(now, req_peer->pre_send_jif + ent))
1784 ? req_peer->pre_send_jif + ent : now + et;
1785 dt = (dt && oldest_submit_jif != now && time_before(now, oldest_submit_jif + dt))
1786 ? oldest_submit_jif + dt : now + et;
1787 nt = time_before(ent, dt) ? ent : dt;
1788out:
1789 spin_unlock_irq(&device->resource->req_lock);
1790 mod_timer(&device->request_timer, nt);
1791}