Merge tag 'module-implicit-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel...
[deliverable/linux.git] / drivers / block / drbd / drbd_req.c
1 /*
2 drbd_req.c
3
4 This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
5
6 Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
7 Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
8 Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
9
10 drbd is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2, or (at your option)
13 any later version.
14
15 drbd is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with drbd; see the file COPYING. If not, write to
22 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
23
24 */
25
26 #include <linux/module.h>
27
28 #include <linux/slab.h>
29 #include <linux/drbd.h>
30 #include "drbd_int.h"
31 #include "drbd_req.h"
32
33
34 static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size);
35
36 /* Update disk stats at start of I/O request */
37 static void _drbd_start_io_acct(struct drbd_device *device, struct drbd_request *req)
38 {
39 generic_start_io_acct(bio_data_dir(req->master_bio), req->i.size >> 9,
40 &device->vdisk->part0);
41 }
42
43 /* Update disk stats when completing request upwards */
44 static void _drbd_end_io_acct(struct drbd_device *device, struct drbd_request *req)
45 {
46 generic_end_io_acct(bio_data_dir(req->master_bio),
47 &device->vdisk->part0, req->start_jif);
48 }
49
50 static struct drbd_request *drbd_req_new(struct drbd_device *device,
51 struct bio *bio_src)
52 {
53 struct drbd_request *req;
54
55 req = mempool_alloc(drbd_request_mempool, GFP_NOIO);
56 if (!req)
57 return NULL;
58 memset(req, 0, sizeof(*req));
59
60 drbd_req_make_private_bio(req, bio_src);
61 req->rq_state = bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0;
62 req->device = device;
63 req->master_bio = bio_src;
64 req->epoch = 0;
65
66 drbd_clear_interval(&req->i);
67 req->i.sector = bio_src->bi_iter.bi_sector;
68 req->i.size = bio_src->bi_iter.bi_size;
69 req->i.local = true;
70 req->i.waiting = false;
71
72 INIT_LIST_HEAD(&req->tl_requests);
73 INIT_LIST_HEAD(&req->w.list);
74 INIT_LIST_HEAD(&req->req_pending_master_completion);
75 INIT_LIST_HEAD(&req->req_pending_local);
76
77 /* one reference to be put by __drbd_make_request */
78 atomic_set(&req->completion_ref, 1);
79 /* one kref as long as completion_ref > 0 */
80 kref_init(&req->kref);
81 return req;
82 }
83
84 static void drbd_remove_request_interval(struct rb_root *root,
85 struct drbd_request *req)
86 {
87 struct drbd_device *device = req->device;
88 struct drbd_interval *i = &req->i;
89
90 drbd_remove_interval(root, i);
91
92 /* Wake up any processes waiting for this request to complete. */
93 if (i->waiting)
94 wake_up(&device->misc_wait);
95 }
96
97 void drbd_req_destroy(struct kref *kref)
98 {
99 struct drbd_request *req = container_of(kref, struct drbd_request, kref);
100 struct drbd_device *device = req->device;
101 const unsigned s = req->rq_state;
102
103 if ((req->master_bio && !(s & RQ_POSTPONED)) ||
104 atomic_read(&req->completion_ref) ||
105 (s & RQ_LOCAL_PENDING) ||
106 ((s & RQ_NET_MASK) && !(s & RQ_NET_DONE))) {
107 drbd_err(device, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n",
108 s, atomic_read(&req->completion_ref));
109 return;
110 }
111
112 /* If called from mod_rq_state (expected normal case) or
113 * drbd_send_and_submit (the less likely normal path), this holds the
114 * req_lock, and req->tl_requests will typicaly be on ->transfer_log,
115 * though it may be still empty (never added to the transfer log).
116 *
117 * If called from do_retry(), we do NOT hold the req_lock, but we are
118 * still allowed to unconditionally list_del(&req->tl_requests),
119 * because it will be on a local on-stack list only. */
120 list_del_init(&req->tl_requests);
121
122 /* finally remove the request from the conflict detection
123 * respective block_id verification interval tree. */
124 if (!drbd_interval_empty(&req->i)) {
125 struct rb_root *root;
126
127 if (s & RQ_WRITE)
128 root = &device->write_requests;
129 else
130 root = &device->read_requests;
131 drbd_remove_request_interval(root, req);
132 } else if (s & (RQ_NET_MASK & ~RQ_NET_DONE) && req->i.size != 0)
133 drbd_err(device, "drbd_req_destroy: Logic BUG: interval empty, but: rq_state=0x%x, sect=%llu, size=%u\n",
134 s, (unsigned long long)req->i.sector, req->i.size);
135
136 /* if it was a write, we may have to set the corresponding
137 * bit(s) out-of-sync first. If it had a local part, we need to
138 * release the reference to the activity log. */
139 if (s & RQ_WRITE) {
140 /* Set out-of-sync unless both OK flags are set
141 * (local only or remote failed).
142 * Other places where we set out-of-sync:
143 * READ with local io-error */
144
145 /* There is a special case:
146 * we may notice late that IO was suspended,
147 * and postpone, or schedule for retry, a write,
148 * before it even was submitted or sent.
149 * In that case we do not want to touch the bitmap at all.
150 */
151 if ((s & (RQ_POSTPONED|RQ_LOCAL_MASK|RQ_NET_MASK)) != RQ_POSTPONED) {
152 if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK))
153 drbd_set_out_of_sync(device, req->i.sector, req->i.size);
154
155 if ((s & RQ_NET_OK) && (s & RQ_LOCAL_OK) && (s & RQ_NET_SIS))
156 drbd_set_in_sync(device, req->i.sector, req->i.size);
157 }
158
159 /* one might be tempted to move the drbd_al_complete_io
160 * to the local io completion callback drbd_request_endio.
161 * but, if this was a mirror write, we may only
162 * drbd_al_complete_io after this is RQ_NET_DONE,
163 * otherwise the extent could be dropped from the al
164 * before it has actually been written on the peer.
165 * if we crash before our peer knows about the request,
166 * but after the extent has been dropped from the al,
167 * we would forget to resync the corresponding extent.
168 */
169 if (s & RQ_IN_ACT_LOG) {
170 if (get_ldev_if_state(device, D_FAILED)) {
171 drbd_al_complete_io(device, &req->i);
172 put_ldev(device);
173 } else if (__ratelimit(&drbd_ratelimit_state)) {
174 drbd_warn(device, "Should have called drbd_al_complete_io(, %llu, %u), "
175 "but my Disk seems to have failed :(\n",
176 (unsigned long long) req->i.sector, req->i.size);
177 }
178 }
179 }
180
181 mempool_free(req, drbd_request_mempool);
182 }
183
184 static void wake_all_senders(struct drbd_connection *connection)
185 {
186 wake_up(&connection->sender_work.q_wait);
187 }
188
189 /* must hold resource->req_lock */
190 void start_new_tl_epoch(struct drbd_connection *connection)
191 {
192 /* no point closing an epoch, if it is empty, anyways. */
193 if (connection->current_tle_writes == 0)
194 return;
195
196 connection->current_tle_writes = 0;
197 atomic_inc(&connection->current_tle_nr);
198 wake_all_senders(connection);
199 }
200
201 void complete_master_bio(struct drbd_device *device,
202 struct bio_and_error *m)
203 {
204 bio_endio(m->bio, m->error);
205 dec_ap_bio(device);
206 }
207
208
209 /* Helper for __req_mod().
210 * Set m->bio to the master bio, if it is fit to be completed,
211 * or leave it alone (it is initialized to NULL in __req_mod),
212 * if it has already been completed, or cannot be completed yet.
213 * If m->bio is set, the error status to be returned is placed in m->error.
214 */
215 static
216 void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m)
217 {
218 const unsigned s = req->rq_state;
219 struct drbd_device *device = req->device;
220 int rw;
221 int error, ok;
222
223 /* we must not complete the master bio, while it is
224 * still being processed by _drbd_send_zc_bio (drbd_send_dblock)
225 * not yet acknowledged by the peer
226 * not yet completed by the local io subsystem
227 * these flags may get cleared in any order by
228 * the worker,
229 * the receiver,
230 * the bio_endio completion callbacks.
231 */
232 if ((s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) ||
233 (s & RQ_NET_QUEUED) || (s & RQ_NET_PENDING) ||
234 (s & RQ_COMPLETION_SUSP)) {
235 drbd_err(device, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s);
236 return;
237 }
238
239 if (!req->master_bio) {
240 drbd_err(device, "drbd_req_complete: Logic BUG, master_bio == NULL!\n");
241 return;
242 }
243
244 rw = bio_rw(req->master_bio);
245
246 /*
247 * figure out whether to report success or failure.
248 *
249 * report success when at least one of the operations succeeded.
250 * or, to put the other way,
251 * only report failure, when both operations failed.
252 *
253 * what to do about the failures is handled elsewhere.
254 * what we need to do here is just: complete the master_bio.
255 *
256 * local completion error, if any, has been stored as ERR_PTR
257 * in private_bio within drbd_request_endio.
258 */
259 ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK);
260 error = PTR_ERR(req->private_bio);
261
262 /* Before we can signal completion to the upper layers,
263 * we may need to close the current transfer log epoch.
264 * We are within the request lock, so we can simply compare
265 * the request epoch number with the current transfer log
266 * epoch number. If they match, increase the current_tle_nr,
267 * and reset the transfer log epoch write_cnt.
268 */
269 if (rw == WRITE &&
270 req->epoch == atomic_read(&first_peer_device(device)->connection->current_tle_nr))
271 start_new_tl_epoch(first_peer_device(device)->connection);
272
273 /* Update disk stats */
274 _drbd_end_io_acct(device, req);
275
276 /* If READ failed,
277 * have it be pushed back to the retry work queue,
278 * so it will re-enter __drbd_make_request(),
279 * and be re-assigned to a suitable local or remote path,
280 * or failed if we do not have access to good data anymore.
281 *
282 * Unless it was failed early by __drbd_make_request(),
283 * because no path was available, in which case
284 * it was not even added to the transfer_log.
285 *
286 * READA may fail, and will not be retried.
287 *
288 * WRITE should have used all available paths already.
289 */
290 if (!ok && rw == READ && !list_empty(&req->tl_requests))
291 req->rq_state |= RQ_POSTPONED;
292
293 if (!(req->rq_state & RQ_POSTPONED)) {
294 m->error = ok ? 0 : (error ?: -EIO);
295 m->bio = req->master_bio;
296 req->master_bio = NULL;
297 /* We leave it in the tree, to be able to verify later
298 * write-acks in protocol != C during resync.
299 * But we mark it as "complete", so it won't be counted as
300 * conflict in a multi-primary setup. */
301 req->i.completed = true;
302 }
303
304 if (req->i.waiting)
305 wake_up(&device->misc_wait);
306
307 /* Either we are about to complete to upper layers,
308 * or we will restart this request.
309 * In either case, the request object will be destroyed soon,
310 * so better remove it from all lists. */
311 list_del_init(&req->req_pending_master_completion);
312 }
313
314 /* still holds resource->req_lock */
315 static int drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put)
316 {
317 struct drbd_device *device = req->device;
318 D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED));
319
320 if (!atomic_sub_and_test(put, &req->completion_ref))
321 return 0;
322
323 drbd_req_complete(req, m);
324
325 if (req->rq_state & RQ_POSTPONED) {
326 /* don't destroy the req object just yet,
327 * but queue it for retry */
328 drbd_restart_request(req);
329 return 0;
330 }
331
332 return 1;
333 }
334
335 static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req)
336 {
337 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
338 if (!connection)
339 return;
340 if (connection->req_next == NULL)
341 connection->req_next = req;
342 }
343
344 static void advance_conn_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req)
345 {
346 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
347 if (!connection)
348 return;
349 if (connection->req_next != req)
350 return;
351 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) {
352 const unsigned s = req->rq_state;
353 if (s & RQ_NET_QUEUED)
354 break;
355 }
356 if (&req->tl_requests == &connection->transfer_log)
357 req = NULL;
358 connection->req_next = req;
359 }
360
361 static void set_if_null_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req)
362 {
363 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
364 if (!connection)
365 return;
366 if (connection->req_ack_pending == NULL)
367 connection->req_ack_pending = req;
368 }
369
370 static void advance_conn_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req)
371 {
372 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
373 if (!connection)
374 return;
375 if (connection->req_ack_pending != req)
376 return;
377 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) {
378 const unsigned s = req->rq_state;
379 if ((s & RQ_NET_SENT) && (s & RQ_NET_PENDING))
380 break;
381 }
382 if (&req->tl_requests == &connection->transfer_log)
383 req = NULL;
384 connection->req_ack_pending = req;
385 }
386
387 static void set_if_null_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req)
388 {
389 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
390 if (!connection)
391 return;
392 if (connection->req_not_net_done == NULL)
393 connection->req_not_net_done = req;
394 }
395
396 static void advance_conn_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req)
397 {
398 struct drbd_connection *connection = peer_device ? peer_device->connection : NULL;
399 if (!connection)
400 return;
401 if (connection->req_not_net_done != req)
402 return;
403 list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) {
404 const unsigned s = req->rq_state;
405 if ((s & RQ_NET_SENT) && !(s & RQ_NET_DONE))
406 break;
407 }
408 if (&req->tl_requests == &connection->transfer_log)
409 req = NULL;
410 connection->req_not_net_done = req;
411 }
412
413 /* I'd like this to be the only place that manipulates
414 * req->completion_ref and req->kref. */
415 static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
416 int clear, int set)
417 {
418 struct drbd_device *device = req->device;
419 struct drbd_peer_device *peer_device = first_peer_device(device);
420 unsigned s = req->rq_state;
421 int c_put = 0;
422 int k_put = 0;
423
424 if (drbd_suspended(device) && !((s | clear) & RQ_COMPLETION_SUSP))
425 set |= RQ_COMPLETION_SUSP;
426
427 /* apply */
428
429 req->rq_state &= ~clear;
430 req->rq_state |= set;
431
432 /* no change? */
433 if (req->rq_state == s)
434 return;
435
436 /* intent: get references */
437
438 if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING))
439 atomic_inc(&req->completion_ref);
440
441 if (!(s & RQ_NET_PENDING) && (set & RQ_NET_PENDING)) {
442 inc_ap_pending(device);
443 atomic_inc(&req->completion_ref);
444 }
445
446 if (!(s & RQ_NET_QUEUED) && (set & RQ_NET_QUEUED)) {
447 atomic_inc(&req->completion_ref);
448 set_if_null_req_next(peer_device, req);
449 }
450
451 if (!(s & RQ_EXP_BARR_ACK) && (set & RQ_EXP_BARR_ACK))
452 kref_get(&req->kref); /* wait for the DONE */
453
454 if (!(s & RQ_NET_SENT) && (set & RQ_NET_SENT)) {
455 /* potentially already completed in the asender thread */
456 if (!(s & RQ_NET_DONE)) {
457 atomic_add(req->i.size >> 9, &device->ap_in_flight);
458 set_if_null_req_not_net_done(peer_device, req);
459 }
460 if (s & RQ_NET_PENDING)
461 set_if_null_req_ack_pending(peer_device, req);
462 }
463
464 if (!(s & RQ_COMPLETION_SUSP) && (set & RQ_COMPLETION_SUSP))
465 atomic_inc(&req->completion_ref);
466
467 /* progress: put references */
468
469 if ((s & RQ_COMPLETION_SUSP) && (clear & RQ_COMPLETION_SUSP))
470 ++c_put;
471
472 if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) {
473 D_ASSERT(device, req->rq_state & RQ_LOCAL_PENDING);
474 /* local completion may still come in later,
475 * we need to keep the req object around. */
476 kref_get(&req->kref);
477 ++c_put;
478 }
479
480 if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) {
481 if (req->rq_state & RQ_LOCAL_ABORTED)
482 ++k_put;
483 else
484 ++c_put;
485 list_del_init(&req->req_pending_local);
486 }
487
488 if ((s & RQ_NET_PENDING) && (clear & RQ_NET_PENDING)) {
489 dec_ap_pending(device);
490 ++c_put;
491 req->acked_jif = jiffies;
492 advance_conn_req_ack_pending(peer_device, req);
493 }
494
495 if ((s & RQ_NET_QUEUED) && (clear & RQ_NET_QUEUED)) {
496 ++c_put;
497 advance_conn_req_next(peer_device, req);
498 }
499
500 if (!(s & RQ_NET_DONE) && (set & RQ_NET_DONE)) {
501 if (s & RQ_NET_SENT)
502 atomic_sub(req->i.size >> 9, &device->ap_in_flight);
503 if (s & RQ_EXP_BARR_ACK)
504 ++k_put;
505 req->net_done_jif = jiffies;
506
507 /* in ahead/behind mode, or just in case,
508 * before we finally destroy this request,
509 * the caching pointers must not reference it anymore */
510 advance_conn_req_next(peer_device, req);
511 advance_conn_req_ack_pending(peer_device, req);
512 advance_conn_req_not_net_done(peer_device, req);
513 }
514
515 /* potentially complete and destroy */
516
517 if (k_put || c_put) {
518 /* Completion does it's own kref_put. If we are going to
519 * kref_sub below, we need req to be still around then. */
520 int at_least = k_put + !!c_put;
521 int refcount = atomic_read(&req->kref.refcount);
522 if (refcount < at_least)
523 drbd_err(device,
524 "mod_rq_state: Logic BUG: %x -> %x: refcount = %d, should be >= %d\n",
525 s, req->rq_state, refcount, at_least);
526 }
527
528 /* If we made progress, retry conflicting peer requests, if any. */
529 if (req->i.waiting)
530 wake_up(&device->misc_wait);
531
532 if (c_put)
533 k_put += drbd_req_put_completion_ref(req, m, c_put);
534 if (k_put)
535 kref_sub(&req->kref, k_put, drbd_req_destroy);
536 }
537
538 static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req)
539 {
540 char b[BDEVNAME_SIZE];
541
542 if (!__ratelimit(&drbd_ratelimit_state))
543 return;
544
545 drbd_warn(device, "local %s IO error sector %llu+%u on %s\n",
546 (req->rq_state & RQ_WRITE) ? "WRITE" : "READ",
547 (unsigned long long)req->i.sector,
548 req->i.size >> 9,
549 bdevname(device->ldev->backing_bdev, b));
550 }
551
552 /* Helper for HANDED_OVER_TO_NETWORK.
553 * Is this a protocol A write (neither WRITE_ACK nor RECEIVE_ACK expected)?
554 * Is it also still "PENDING"?
555 * --> If so, clear PENDING and set NET_OK below.
556 * If it is a protocol A write, but not RQ_PENDING anymore, neg-ack was faster
557 * (and we must not set RQ_NET_OK) */
558 static inline bool is_pending_write_protocol_A(struct drbd_request *req)
559 {
560 return (req->rq_state &
561 (RQ_WRITE|RQ_NET_PENDING|RQ_EXP_WRITE_ACK|RQ_EXP_RECEIVE_ACK))
562 == (RQ_WRITE|RQ_NET_PENDING);
563 }
564
565 /* obviously this could be coded as many single functions
566 * instead of one huge switch,
567 * or by putting the code directly in the respective locations
568 * (as it has been before).
569 *
570 * but having it this way
571 * enforces that it is all in this one place, where it is easier to audit,
572 * it makes it obvious that whatever "event" "happens" to a request should
573 * happen "atomically" within the req_lock,
574 * and it enforces that we have to think in a very structured manner
575 * about the "events" that may happen to a request during its life time ...
576 */
577 int __req_mod(struct drbd_request *req, enum drbd_req_event what,
578 struct bio_and_error *m)
579 {
580 struct drbd_device *const device = req->device;
581 struct drbd_peer_device *const peer_device = first_peer_device(device);
582 struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL;
583 struct net_conf *nc;
584 int p, rv = 0;
585
586 if (m)
587 m->bio = NULL;
588
589 switch (what) {
590 default:
591 drbd_err(device, "LOGIC BUG in %s:%u\n", __FILE__ , __LINE__);
592 break;
593
594 /* does not happen...
595 * initialization done in drbd_req_new
596 case CREATED:
597 break;
598 */
599
600 case TO_BE_SENT: /* via network */
601 /* reached via __drbd_make_request
602 * and from w_read_retry_remote */
603 D_ASSERT(device, !(req->rq_state & RQ_NET_MASK));
604 rcu_read_lock();
605 nc = rcu_dereference(connection->net_conf);
606 p = nc->wire_protocol;
607 rcu_read_unlock();
608 req->rq_state |=
609 p == DRBD_PROT_C ? RQ_EXP_WRITE_ACK :
610 p == DRBD_PROT_B ? RQ_EXP_RECEIVE_ACK : 0;
611 mod_rq_state(req, m, 0, RQ_NET_PENDING);
612 break;
613
614 case TO_BE_SUBMITTED: /* locally */
615 /* reached via __drbd_make_request */
616 D_ASSERT(device, !(req->rq_state & RQ_LOCAL_MASK));
617 mod_rq_state(req, m, 0, RQ_LOCAL_PENDING);
618 break;
619
620 case COMPLETED_OK:
621 if (req->rq_state & RQ_WRITE)
622 device->writ_cnt += req->i.size >> 9;
623 else
624 device->read_cnt += req->i.size >> 9;
625
626 mod_rq_state(req, m, RQ_LOCAL_PENDING,
627 RQ_LOCAL_COMPLETED|RQ_LOCAL_OK);
628 break;
629
630 case ABORT_DISK_IO:
631 mod_rq_state(req, m, 0, RQ_LOCAL_ABORTED);
632 break;
633
634 case WRITE_COMPLETED_WITH_ERROR:
635 drbd_report_io_error(device, req);
636 __drbd_chk_io_error(device, DRBD_WRITE_ERROR);
637 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
638 break;
639
640 case READ_COMPLETED_WITH_ERROR:
641 drbd_set_out_of_sync(device, req->i.sector, req->i.size);
642 drbd_report_io_error(device, req);
643 __drbd_chk_io_error(device, DRBD_READ_ERROR);
644 /* fall through. */
645 case READ_AHEAD_COMPLETED_WITH_ERROR:
646 /* it is legal to fail READA, no __drbd_chk_io_error in that case. */
647 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
648 break;
649
650 case DISCARD_COMPLETED_NOTSUPP:
651 case DISCARD_COMPLETED_WITH_ERROR:
652 /* I'd rather not detach from local disk just because it
653 * failed a REQ_DISCARD. */
654 mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
655 break;
656
657 case QUEUE_FOR_NET_READ:
658 /* READ or READA, and
659 * no local disk,
660 * or target area marked as invalid,
661 * or just got an io-error. */
662 /* from __drbd_make_request
663 * or from bio_endio during read io-error recovery */
664
665 /* So we can verify the handle in the answer packet.
666 * Corresponding drbd_remove_request_interval is in
667 * drbd_req_complete() */
668 D_ASSERT(device, drbd_interval_empty(&req->i));
669 drbd_insert_interval(&device->read_requests, &req->i);
670
671 set_bit(UNPLUG_REMOTE, &device->flags);
672
673 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
674 D_ASSERT(device, (req->rq_state & RQ_LOCAL_MASK) == 0);
675 mod_rq_state(req, m, 0, RQ_NET_QUEUED);
676 req->w.cb = w_send_read_req;
677 drbd_queue_work(&connection->sender_work,
678 &req->w);
679 break;
680
681 case QUEUE_FOR_NET_WRITE:
682 /* assert something? */
683 /* from __drbd_make_request only */
684
685 /* Corresponding drbd_remove_request_interval is in
686 * drbd_req_complete() */
687 D_ASSERT(device, drbd_interval_empty(&req->i));
688 drbd_insert_interval(&device->write_requests, &req->i);
689
690 /* NOTE
691 * In case the req ended up on the transfer log before being
692 * queued on the worker, it could lead to this request being
693 * missed during cleanup after connection loss.
694 * So we have to do both operations here,
695 * within the same lock that protects the transfer log.
696 *
697 * _req_add_to_epoch(req); this has to be after the
698 * _maybe_start_new_epoch(req); which happened in
699 * __drbd_make_request, because we now may set the bit
700 * again ourselves to close the current epoch.
701 *
702 * Add req to the (now) current epoch (barrier). */
703
704 /* otherwise we may lose an unplug, which may cause some remote
705 * io-scheduler timeout to expire, increasing maximum latency,
706 * hurting performance. */
707 set_bit(UNPLUG_REMOTE, &device->flags);
708
709 /* queue work item to send data */
710 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
711 mod_rq_state(req, m, 0, RQ_NET_QUEUED|RQ_EXP_BARR_ACK);
712 req->w.cb = w_send_dblock;
713 drbd_queue_work(&connection->sender_work,
714 &req->w);
715
716 /* close the epoch, in case it outgrew the limit */
717 rcu_read_lock();
718 nc = rcu_dereference(connection->net_conf);
719 p = nc->max_epoch_size;
720 rcu_read_unlock();
721 if (connection->current_tle_writes >= p)
722 start_new_tl_epoch(connection);
723
724 break;
725
726 case QUEUE_FOR_SEND_OOS:
727 mod_rq_state(req, m, 0, RQ_NET_QUEUED);
728 req->w.cb = w_send_out_of_sync;
729 drbd_queue_work(&connection->sender_work,
730 &req->w);
731 break;
732
733 case READ_RETRY_REMOTE_CANCELED:
734 case SEND_CANCELED:
735 case SEND_FAILED:
736 /* real cleanup will be done from tl_clear. just update flags
737 * so it is no longer marked as on the worker queue */
738 mod_rq_state(req, m, RQ_NET_QUEUED, 0);
739 break;
740
741 case HANDED_OVER_TO_NETWORK:
742 /* assert something? */
743 if (is_pending_write_protocol_A(req))
744 /* this is what is dangerous about protocol A:
745 * pretend it was successfully written on the peer. */
746 mod_rq_state(req, m, RQ_NET_QUEUED|RQ_NET_PENDING,
747 RQ_NET_SENT|RQ_NET_OK);
748 else
749 mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_SENT);
750 /* It is still not yet RQ_NET_DONE until the
751 * corresponding epoch barrier got acked as well,
752 * so we know what to dirty on connection loss. */
753 break;
754
755 case OOS_HANDED_TO_NETWORK:
756 /* Was not set PENDING, no longer QUEUED, so is now DONE
757 * as far as this connection is concerned. */
758 mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_DONE);
759 break;
760
761 case CONNECTION_LOST_WHILE_PENDING:
762 /* transfer log cleanup after connection loss */
763 mod_rq_state(req, m,
764 RQ_NET_OK|RQ_NET_PENDING|RQ_COMPLETION_SUSP,
765 RQ_NET_DONE);
766 break;
767
768 case CONFLICT_RESOLVED:
769 /* for superseded conflicting writes of multiple primaries,
770 * there is no need to keep anything in the tl, potential
771 * node crashes are covered by the activity log.
772 *
773 * If this request had been marked as RQ_POSTPONED before,
774 * it will actually not be completed, but "restarted",
775 * resubmitted from the retry worker context. */
776 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
777 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK);
778 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_DONE|RQ_NET_OK);
779 break;
780
781 case WRITE_ACKED_BY_PEER_AND_SIS:
782 req->rq_state |= RQ_NET_SIS;
783 case WRITE_ACKED_BY_PEER:
784 /* Normal operation protocol C: successfully written on peer.
785 * During resync, even in protocol != C,
786 * we requested an explicit write ack anyways.
787 * Which means we cannot even assert anything here.
788 * Nothing more to do here.
789 * We want to keep the tl in place for all protocols, to cater
790 * for volatile write-back caches on lower level devices. */
791 goto ack_common;
792 case RECV_ACKED_BY_PEER:
793 D_ASSERT(device, req->rq_state & RQ_EXP_RECEIVE_ACK);
794 /* protocol B; pretends to be successfully written on peer.
795 * see also notes above in HANDED_OVER_TO_NETWORK about
796 * protocol != C */
797 ack_common:
798 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK);
799 break;
800
801 case POSTPONE_WRITE:
802 D_ASSERT(device, req->rq_state & RQ_EXP_WRITE_ACK);
803 /* If this node has already detected the write conflict, the
804 * worker will be waiting on misc_wait. Wake it up once this
805 * request has completed locally.
806 */
807 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
808 req->rq_state |= RQ_POSTPONED;
809 if (req->i.waiting)
810 wake_up(&device->misc_wait);
811 /* Do not clear RQ_NET_PENDING. This request will make further
812 * progress via restart_conflicting_writes() or
813 * fail_postponed_requests(). Hopefully. */
814 break;
815
816 case NEG_ACKED:
817 mod_rq_state(req, m, RQ_NET_OK|RQ_NET_PENDING, 0);
818 break;
819
820 case FAIL_FROZEN_DISK_IO:
821 if (!(req->rq_state & RQ_LOCAL_COMPLETED))
822 break;
823 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0);
824 break;
825
826 case RESTART_FROZEN_DISK_IO:
827 if (!(req->rq_state & RQ_LOCAL_COMPLETED))
828 break;
829
830 mod_rq_state(req, m,
831 RQ_COMPLETION_SUSP|RQ_LOCAL_COMPLETED,
832 RQ_LOCAL_PENDING);
833
834 rv = MR_READ;
835 if (bio_data_dir(req->master_bio) == WRITE)
836 rv = MR_WRITE;
837
838 get_ldev(device); /* always succeeds in this call path */
839 req->w.cb = w_restart_disk_io;
840 drbd_queue_work(&connection->sender_work,
841 &req->w);
842 break;
843
844 case RESEND:
845 /* Simply complete (local only) READs. */
846 if (!(req->rq_state & RQ_WRITE) && !req->w.cb) {
847 mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0);
848 break;
849 }
850
851 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK
852 before the connection loss (B&C only); only P_BARRIER_ACK
853 (or the local completion?) was missing when we suspended.
854 Throwing them out of the TL here by pretending we got a BARRIER_ACK.
855 During connection handshake, we ensure that the peer was not rebooted. */
856 if (!(req->rq_state & RQ_NET_OK)) {
857 /* FIXME could this possibly be a req->dw.cb == w_send_out_of_sync?
858 * in that case we must not set RQ_NET_PENDING. */
859
860 mod_rq_state(req, m, RQ_COMPLETION_SUSP, RQ_NET_QUEUED|RQ_NET_PENDING);
861 if (req->w.cb) {
862 /* w.cb expected to be w_send_dblock, or w_send_read_req */
863 drbd_queue_work(&connection->sender_work,
864 &req->w);
865 rv = req->rq_state & RQ_WRITE ? MR_WRITE : MR_READ;
866 } /* else: FIXME can this happen? */
867 break;
868 }
869 /* else, fall through to BARRIER_ACKED */
870
871 case BARRIER_ACKED:
872 /* barrier ack for READ requests does not make sense */
873 if (!(req->rq_state & RQ_WRITE))
874 break;
875
876 if (req->rq_state & RQ_NET_PENDING) {
877 /* barrier came in before all requests were acked.
878 * this is bad, because if the connection is lost now,
879 * we won't be able to clean them up... */
880 drbd_err(device, "FIXME (BARRIER_ACKED but pending)\n");
881 }
882 /* Allowed to complete requests, even while suspended.
883 * As this is called for all requests within a matching epoch,
884 * we need to filter, and only set RQ_NET_DONE for those that
885 * have actually been on the wire. */
886 mod_rq_state(req, m, RQ_COMPLETION_SUSP,
887 (req->rq_state & RQ_NET_MASK) ? RQ_NET_DONE : 0);
888 break;
889
890 case DATA_RECEIVED:
891 D_ASSERT(device, req->rq_state & RQ_NET_PENDING);
892 mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE);
893 break;
894
895 case QUEUE_AS_DRBD_BARRIER:
896 start_new_tl_epoch(connection);
897 mod_rq_state(req, m, 0, RQ_NET_OK|RQ_NET_DONE);
898 break;
899 };
900
901 return rv;
902 }
903
904 /* we may do a local read if:
905 * - we are consistent (of course),
906 * - or we are generally inconsistent,
907 * BUT we are still/already IN SYNC for this area.
908 * since size may be bigger than BM_BLOCK_SIZE,
909 * we may need to check several bits.
910 */
911 static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size)
912 {
913 unsigned long sbnr, ebnr;
914 sector_t esector, nr_sectors;
915
916 if (device->state.disk == D_UP_TO_DATE)
917 return true;
918 if (device->state.disk != D_INCONSISTENT)
919 return false;
920 esector = sector + (size >> 9) - 1;
921 nr_sectors = drbd_get_capacity(device->this_bdev);
922 D_ASSERT(device, sector < nr_sectors);
923 D_ASSERT(device, esector < nr_sectors);
924
925 sbnr = BM_SECT_TO_BIT(sector);
926 ebnr = BM_SECT_TO_BIT(esector);
927
928 return drbd_bm_count_bits(device, sbnr, ebnr) == 0;
929 }
930
931 static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t sector,
932 enum drbd_read_balancing rbm)
933 {
934 struct backing_dev_info *bdi;
935 int stripe_shift;
936
937 switch (rbm) {
938 case RB_CONGESTED_REMOTE:
939 bdi = &device->ldev->backing_bdev->bd_disk->queue->backing_dev_info;
940 return bdi_read_congested(bdi);
941 case RB_LEAST_PENDING:
942 return atomic_read(&device->local_cnt) >
943 atomic_read(&device->ap_pending_cnt) + atomic_read(&device->rs_pending_cnt);
944 case RB_32K_STRIPING: /* stripe_shift = 15 */
945 case RB_64K_STRIPING:
946 case RB_128K_STRIPING:
947 case RB_256K_STRIPING:
948 case RB_512K_STRIPING:
949 case RB_1M_STRIPING: /* stripe_shift = 20 */
950 stripe_shift = (rbm - RB_32K_STRIPING + 15);
951 return (sector >> (stripe_shift - 9)) & 1;
952 case RB_ROUND_ROBIN:
953 return test_and_change_bit(READ_BALANCE_RR, &device->flags);
954 case RB_PREFER_REMOTE:
955 return true;
956 case RB_PREFER_LOCAL:
957 default:
958 return false;
959 }
960 }
961
962 /*
963 * complete_conflicting_writes - wait for any conflicting write requests
964 *
965 * The write_requests tree contains all active write requests which we
966 * currently know about. Wait for any requests to complete which conflict with
967 * the new one.
968 *
969 * Only way out: remove the conflicting intervals from the tree.
970 */
971 static void complete_conflicting_writes(struct drbd_request *req)
972 {
973 DEFINE_WAIT(wait);
974 struct drbd_device *device = req->device;
975 struct drbd_interval *i;
976 sector_t sector = req->i.sector;
977 int size = req->i.size;
978
979 i = drbd_find_overlap(&device->write_requests, sector, size);
980 if (!i)
981 return;
982
983 for (;;) {
984 prepare_to_wait(&device->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
985 i = drbd_find_overlap(&device->write_requests, sector, size);
986 if (!i)
987 break;
988 /* Indicate to wake up device->misc_wait on progress. */
989 i->waiting = true;
990 spin_unlock_irq(&device->resource->req_lock);
991 schedule();
992 spin_lock_irq(&device->resource->req_lock);
993 }
994 finish_wait(&device->misc_wait, &wait);
995 }
996
997 /* called within req_lock and rcu_read_lock() */
998 static void maybe_pull_ahead(struct drbd_device *device)
999 {
1000 struct drbd_connection *connection = first_peer_device(device)->connection;
1001 struct net_conf *nc;
1002 bool congested = false;
1003 enum drbd_on_congestion on_congestion;
1004
1005 rcu_read_lock();
1006 nc = rcu_dereference(connection->net_conf);
1007 on_congestion = nc ? nc->on_congestion : OC_BLOCK;
1008 rcu_read_unlock();
1009 if (on_congestion == OC_BLOCK ||
1010 connection->agreed_pro_version < 96)
1011 return;
1012
1013 if (on_congestion == OC_PULL_AHEAD && device->state.conn == C_AHEAD)
1014 return; /* nothing to do ... */
1015
1016 /* If I don't even have good local storage, we can not reasonably try
1017 * to pull ahead of the peer. We also need the local reference to make
1018 * sure device->act_log is there.
1019 */
1020 if (!get_ldev_if_state(device, D_UP_TO_DATE))
1021 return;
1022
1023 if (nc->cong_fill &&
1024 atomic_read(&device->ap_in_flight) >= nc->cong_fill) {
1025 drbd_info(device, "Congestion-fill threshold reached\n");
1026 congested = true;
1027 }
1028
1029 if (device->act_log->used >= nc->cong_extents) {
1030 drbd_info(device, "Congestion-extents threshold reached\n");
1031 congested = true;
1032 }
1033
1034 if (congested) {
1035 /* start a new epoch for non-mirrored writes */
1036 start_new_tl_epoch(first_peer_device(device)->connection);
1037
1038 if (on_congestion == OC_PULL_AHEAD)
1039 _drbd_set_state(_NS(device, conn, C_AHEAD), 0, NULL);
1040 else /*nc->on_congestion == OC_DISCONNECT */
1041 _drbd_set_state(_NS(device, conn, C_DISCONNECTING), 0, NULL);
1042 }
1043 put_ldev(device);
1044 }
1045
1046 /* If this returns false, and req->private_bio is still set,
1047 * this should be submitted locally.
1048 *
1049 * If it returns false, but req->private_bio is not set,
1050 * we do not have access to good data :(
1051 *
1052 * Otherwise, this destroys req->private_bio, if any,
1053 * and returns true.
1054 */
1055 static bool do_remote_read(struct drbd_request *req)
1056 {
1057 struct drbd_device *device = req->device;
1058 enum drbd_read_balancing rbm;
1059
1060 if (req->private_bio) {
1061 if (!drbd_may_do_local_read(device,
1062 req->i.sector, req->i.size)) {
1063 bio_put(req->private_bio);
1064 req->private_bio = NULL;
1065 put_ldev(device);
1066 }
1067 }
1068
1069 if (device->state.pdsk != D_UP_TO_DATE)
1070 return false;
1071
1072 if (req->private_bio == NULL)
1073 return true;
1074
1075 /* TODO: improve read balancing decisions, take into account drbd
1076 * protocol, pending requests etc. */
1077
1078 rcu_read_lock();
1079 rbm = rcu_dereference(device->ldev->disk_conf)->read_balancing;
1080 rcu_read_unlock();
1081
1082 if (rbm == RB_PREFER_LOCAL && req->private_bio)
1083 return false; /* submit locally */
1084
1085 if (remote_due_to_read_balancing(device, req->i.sector, rbm)) {
1086 if (req->private_bio) {
1087 bio_put(req->private_bio);
1088 req->private_bio = NULL;
1089 put_ldev(device);
1090 }
1091 return true;
1092 }
1093
1094 return false;
1095 }
1096
1097 /* returns number of connections (== 1, for drbd 8.4)
1098 * expected to actually write this data,
1099 * which does NOT include those that we are L_AHEAD for. */
1100 static int drbd_process_write_request(struct drbd_request *req)
1101 {
1102 struct drbd_device *device = req->device;
1103 int remote, send_oos;
1104
1105 remote = drbd_should_do_remote(device->state);
1106 send_oos = drbd_should_send_out_of_sync(device->state);
1107
1108 /* Need to replicate writes. Unless it is an empty flush,
1109 * which is better mapped to a DRBD P_BARRIER packet,
1110 * also for drbd wire protocol compatibility reasons.
1111 * If this was a flush, just start a new epoch.
1112 * Unless the current epoch was empty anyways, or we are not currently
1113 * replicating, in which case there is no point. */
1114 if (unlikely(req->i.size == 0)) {
1115 /* The only size==0 bios we expect are empty flushes. */
1116 D_ASSERT(device, req->master_bio->bi_rw & REQ_FLUSH);
1117 if (remote)
1118 _req_mod(req, QUEUE_AS_DRBD_BARRIER);
1119 return remote;
1120 }
1121
1122 if (!remote && !send_oos)
1123 return 0;
1124
1125 D_ASSERT(device, !(remote && send_oos));
1126
1127 if (remote) {
1128 _req_mod(req, TO_BE_SENT);
1129 _req_mod(req, QUEUE_FOR_NET_WRITE);
1130 } else if (drbd_set_out_of_sync(device, req->i.sector, req->i.size))
1131 _req_mod(req, QUEUE_FOR_SEND_OOS);
1132
1133 return remote;
1134 }
1135
1136 static void
1137 drbd_submit_req_private_bio(struct drbd_request *req)
1138 {
1139 struct drbd_device *device = req->device;
1140 struct bio *bio = req->private_bio;
1141 const int rw = bio_rw(bio);
1142
1143 bio->bi_bdev = device->ldev->backing_bdev;
1144
1145 /* State may have changed since we grabbed our reference on the
1146 * ->ldev member. Double check, and short-circuit to endio.
1147 * In case the last activity log transaction failed to get on
1148 * stable storage, and this is a WRITE, we may not even submit
1149 * this bio. */
1150 if (get_ldev(device)) {
1151 req->pre_submit_jif = jiffies;
1152 if (drbd_insert_fault(device,
1153 rw == WRITE ? DRBD_FAULT_DT_WR
1154 : rw == READ ? DRBD_FAULT_DT_RD
1155 : DRBD_FAULT_DT_RA))
1156 bio_endio(bio, -EIO);
1157 else
1158 generic_make_request(bio);
1159 put_ldev(device);
1160 } else
1161 bio_endio(bio, -EIO);
1162 }
1163
1164 static void drbd_queue_write(struct drbd_device *device, struct drbd_request *req)
1165 {
1166 spin_lock_irq(&device->resource->req_lock);
1167 list_add_tail(&req->tl_requests, &device->submit.writes);
1168 list_add_tail(&req->req_pending_master_completion,
1169 &device->pending_master_completion[1 /* WRITE */]);
1170 spin_unlock_irq(&device->resource->req_lock);
1171 queue_work(device->submit.wq, &device->submit.worker);
1172 /* do_submit() may sleep internally on al_wait, too */
1173 wake_up(&device->al_wait);
1174 }
1175
1176 /* returns the new drbd_request pointer, if the caller is expected to
1177 * drbd_send_and_submit() it (to save latency), or NULL if we queued the
1178 * request on the submitter thread.
1179 * Returns ERR_PTR(-ENOMEM) if we cannot allocate a drbd_request.
1180 */
1181 static struct drbd_request *
1182 drbd_request_prepare(struct drbd_device *device, struct bio *bio, unsigned long start_jif)
1183 {
1184 const int rw = bio_data_dir(bio);
1185 struct drbd_request *req;
1186
1187 /* allocate outside of all locks; */
1188 req = drbd_req_new(device, bio);
1189 if (!req) {
1190 dec_ap_bio(device);
1191 /* only pass the error to the upper layers.
1192 * if user cannot handle io errors, that's not our business. */
1193 drbd_err(device, "could not kmalloc() req\n");
1194 bio_endio(bio, -ENOMEM);
1195 return ERR_PTR(-ENOMEM);
1196 }
1197 req->start_jif = start_jif;
1198
1199 if (!get_ldev(device)) {
1200 bio_put(req->private_bio);
1201 req->private_bio = NULL;
1202 }
1203
1204 /* Update disk stats */
1205 _drbd_start_io_acct(device, req);
1206
1207 if (rw == WRITE && req->private_bio && req->i.size
1208 && !test_bit(AL_SUSPENDED, &device->flags)) {
1209 if (!drbd_al_begin_io_fastpath(device, &req->i)) {
1210 atomic_inc(&device->ap_actlog_cnt);
1211 drbd_queue_write(device, req);
1212 return NULL;
1213 }
1214 req->rq_state |= RQ_IN_ACT_LOG;
1215 req->in_actlog_jif = jiffies;
1216 }
1217
1218 return req;
1219 }
1220
1221 static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request *req)
1222 {
1223 struct drbd_resource *resource = device->resource;
1224 const int rw = bio_rw(req->master_bio);
1225 struct bio_and_error m = { NULL, };
1226 bool no_remote = false;
1227 bool submit_private_bio = false;
1228
1229 spin_lock_irq(&resource->req_lock);
1230 if (rw == WRITE) {
1231 /* This may temporarily give up the req_lock,
1232 * but will re-aquire it before it returns here.
1233 * Needs to be before the check on drbd_suspended() */
1234 complete_conflicting_writes(req);
1235 /* no more giving up req_lock from now on! */
1236
1237 /* check for congestion, and potentially stop sending
1238 * full data updates, but start sending "dirty bits" only. */
1239 maybe_pull_ahead(device);
1240 }
1241
1242
1243 if (drbd_suspended(device)) {
1244 /* push back and retry: */
1245 req->rq_state |= RQ_POSTPONED;
1246 if (req->private_bio) {
1247 bio_put(req->private_bio);
1248 req->private_bio = NULL;
1249 put_ldev(device);
1250 }
1251 goto out;
1252 }
1253
1254 /* We fail READ/READA early, if we can not serve it.
1255 * We must do this before req is registered on any lists.
1256 * Otherwise, drbd_req_complete() will queue failed READ for retry. */
1257 if (rw != WRITE) {
1258 if (!do_remote_read(req) && !req->private_bio)
1259 goto nodata;
1260 }
1261
1262 /* which transfer log epoch does this belong to? */
1263 req->epoch = atomic_read(&first_peer_device(device)->connection->current_tle_nr);
1264
1265 /* no point in adding empty flushes to the transfer log,
1266 * they are mapped to drbd barriers already. */
1267 if (likely(req->i.size!=0)) {
1268 if (rw == WRITE)
1269 first_peer_device(device)->connection->current_tle_writes++;
1270
1271 list_add_tail(&req->tl_requests, &first_peer_device(device)->connection->transfer_log);
1272 }
1273
1274 if (rw == WRITE) {
1275 if (!drbd_process_write_request(req))
1276 no_remote = true;
1277 } else {
1278 /* We either have a private_bio, or we can read from remote.
1279 * Otherwise we had done the goto nodata above. */
1280 if (req->private_bio == NULL) {
1281 _req_mod(req, TO_BE_SENT);
1282 _req_mod(req, QUEUE_FOR_NET_READ);
1283 } else
1284 no_remote = true;
1285 }
1286
1287 /* If it took the fast path in drbd_request_prepare, add it here.
1288 * The slow path has added it already. */
1289 if (list_empty(&req->req_pending_master_completion))
1290 list_add_tail(&req->req_pending_master_completion,
1291 &device->pending_master_completion[rw == WRITE]);
1292 if (req->private_bio) {
1293 /* needs to be marked within the same spinlock */
1294 list_add_tail(&req->req_pending_local,
1295 &device->pending_completion[rw == WRITE]);
1296 _req_mod(req, TO_BE_SUBMITTED);
1297 /* but we need to give up the spinlock to submit */
1298 submit_private_bio = true;
1299 } else if (no_remote) {
1300 nodata:
1301 if (__ratelimit(&drbd_ratelimit_state))
1302 drbd_err(device, "IO ERROR: neither local nor remote data, sector %llu+%u\n",
1303 (unsigned long long)req->i.sector, req->i.size >> 9);
1304 /* A write may have been queued for send_oos, however.
1305 * So we can not simply free it, we must go through drbd_req_put_completion_ref() */
1306 }
1307
1308 out:
1309 if (drbd_req_put_completion_ref(req, &m, 1))
1310 kref_put(&req->kref, drbd_req_destroy);
1311 spin_unlock_irq(&resource->req_lock);
1312
1313 /* Even though above is a kref_put(), this is safe.
1314 * As long as we still need to submit our private bio,
1315 * we hold a completion ref, and the request cannot disappear.
1316 * If however this request did not even have a private bio to submit
1317 * (e.g. remote read), req may already be invalid now.
1318 * That's why we cannot check on req->private_bio. */
1319 if (submit_private_bio)
1320 drbd_submit_req_private_bio(req);
1321 if (m.bio)
1322 complete_master_bio(device, &m);
1323 }
1324
1325 void __drbd_make_request(struct drbd_device *device, struct bio *bio, unsigned long start_jif)
1326 {
1327 struct drbd_request *req = drbd_request_prepare(device, bio, start_jif);
1328 if (IS_ERR_OR_NULL(req))
1329 return;
1330 drbd_send_and_submit(device, req);
1331 }
1332
1333 static void submit_fast_path(struct drbd_device *device, struct list_head *incoming)
1334 {
1335 struct drbd_request *req, *tmp;
1336 list_for_each_entry_safe(req, tmp, incoming, tl_requests) {
1337 const int rw = bio_data_dir(req->master_bio);
1338
1339 if (rw == WRITE /* rw != WRITE should not even end up here! */
1340 && req->private_bio && req->i.size
1341 && !test_bit(AL_SUSPENDED, &device->flags)) {
1342 if (!drbd_al_begin_io_fastpath(device, &req->i))
1343 continue;
1344
1345 req->rq_state |= RQ_IN_ACT_LOG;
1346 req->in_actlog_jif = jiffies;
1347 atomic_dec(&device->ap_actlog_cnt);
1348 }
1349
1350 list_del_init(&req->tl_requests);
1351 drbd_send_and_submit(device, req);
1352 }
1353 }
1354
1355 static bool prepare_al_transaction_nonblock(struct drbd_device *device,
1356 struct list_head *incoming,
1357 struct list_head *pending,
1358 struct list_head *later)
1359 {
1360 struct drbd_request *req, *tmp;
1361 int wake = 0;
1362 int err;
1363
1364 spin_lock_irq(&device->al_lock);
1365 list_for_each_entry_safe(req, tmp, incoming, tl_requests) {
1366 err = drbd_al_begin_io_nonblock(device, &req->i);
1367 if (err == -ENOBUFS)
1368 break;
1369 if (err == -EBUSY)
1370 wake = 1;
1371 if (err)
1372 list_move_tail(&req->tl_requests, later);
1373 else
1374 list_move_tail(&req->tl_requests, pending);
1375 }
1376 spin_unlock_irq(&device->al_lock);
1377 if (wake)
1378 wake_up(&device->al_wait);
1379 return !list_empty(pending);
1380 }
1381
1382 void send_and_submit_pending(struct drbd_device *device, struct list_head *pending)
1383 {
1384 struct drbd_request *req, *tmp;
1385
1386 list_for_each_entry_safe(req, tmp, pending, tl_requests) {
1387 req->rq_state |= RQ_IN_ACT_LOG;
1388 req->in_actlog_jif = jiffies;
1389 atomic_dec(&device->ap_actlog_cnt);
1390 list_del_init(&req->tl_requests);
1391 drbd_send_and_submit(device, req);
1392 }
1393 }
1394
1395 void do_submit(struct work_struct *ws)
1396 {
1397 struct drbd_device *device = container_of(ws, struct drbd_device, submit.worker);
1398 LIST_HEAD(incoming); /* from drbd_make_request() */
1399 LIST_HEAD(pending); /* to be submitted after next AL-transaction commit */
1400 LIST_HEAD(busy); /* blocked by resync requests */
1401
1402 /* grab new incoming requests */
1403 spin_lock_irq(&device->resource->req_lock);
1404 list_splice_tail_init(&device->submit.writes, &incoming);
1405 spin_unlock_irq(&device->resource->req_lock);
1406
1407 for (;;) {
1408 DEFINE_WAIT(wait);
1409
1410 /* move used-to-be-busy back to front of incoming */
1411 list_splice_init(&busy, &incoming);
1412 submit_fast_path(device, &incoming);
1413 if (list_empty(&incoming))
1414 break;
1415
1416 for (;;) {
1417 prepare_to_wait(&device->al_wait, &wait, TASK_UNINTERRUPTIBLE);
1418
1419 list_splice_init(&busy, &incoming);
1420 prepare_al_transaction_nonblock(device, &incoming, &pending, &busy);
1421 if (!list_empty(&pending))
1422 break;
1423
1424 schedule();
1425
1426 /* If all currently "hot" activity log extents are kept busy by
1427 * incoming requests, we still must not totally starve new
1428 * requests to "cold" extents.
1429 * Something left on &incoming means there had not been
1430 * enough update slots available, and the activity log
1431 * has been marked as "starving".
1432 *
1433 * Try again now, without looking for new requests,
1434 * effectively blocking all new requests until we made
1435 * at least _some_ progress with what we currently have.
1436 */
1437 if (!list_empty(&incoming))
1438 continue;
1439
1440 /* Nothing moved to pending, but nothing left
1441 * on incoming: all moved to busy!
1442 * Grab new and iterate. */
1443 spin_lock_irq(&device->resource->req_lock);
1444 list_splice_tail_init(&device->submit.writes, &incoming);
1445 spin_unlock_irq(&device->resource->req_lock);
1446 }
1447 finish_wait(&device->al_wait, &wait);
1448
1449 /* If the transaction was full, before all incoming requests
1450 * had been processed, skip ahead to commit, and iterate
1451 * without splicing in more incoming requests from upper layers.
1452 *
1453 * Else, if all incoming have been processed,
1454 * they have become either "pending" (to be submitted after
1455 * next transaction commit) or "busy" (blocked by resync).
1456 *
1457 * Maybe more was queued, while we prepared the transaction?
1458 * Try to stuff those into this transaction as well.
1459 * Be strictly non-blocking here,
1460 * we already have something to commit.
1461 *
1462 * Commit if we don't make any more progres.
1463 */
1464
1465 while (list_empty(&incoming)) {
1466 LIST_HEAD(more_pending);
1467 LIST_HEAD(more_incoming);
1468 bool made_progress;
1469
1470 /* It is ok to look outside the lock,
1471 * it's only an optimization anyways */
1472 if (list_empty(&device->submit.writes))
1473 break;
1474
1475 spin_lock_irq(&device->resource->req_lock);
1476 list_splice_tail_init(&device->submit.writes, &more_incoming);
1477 spin_unlock_irq(&device->resource->req_lock);
1478
1479 if (list_empty(&more_incoming))
1480 break;
1481
1482 made_progress = prepare_al_transaction_nonblock(device, &more_incoming, &more_pending, &busy);
1483
1484 list_splice_tail_init(&more_pending, &pending);
1485 list_splice_tail_init(&more_incoming, &incoming);
1486 if (!made_progress)
1487 break;
1488 }
1489
1490 drbd_al_begin_io_commit(device);
1491 send_and_submit_pending(device, &pending);
1492 }
1493 }
1494
1495 void drbd_make_request(struct request_queue *q, struct bio *bio)
1496 {
1497 struct drbd_device *device = (struct drbd_device *) q->queuedata;
1498 unsigned long start_jif;
1499
1500 start_jif = jiffies;
1501
1502 /*
1503 * what we "blindly" assume:
1504 */
1505 D_ASSERT(device, IS_ALIGNED(bio->bi_iter.bi_size, 512));
1506
1507 inc_ap_bio(device);
1508 __drbd_make_request(device, bio, start_jif);
1509 }
1510
1511 /* This is called by bio_add_page().
1512 *
1513 * q->max_hw_sectors and other global limits are already enforced there.
1514 *
1515 * We need to call down to our lower level device,
1516 * in case it has special restrictions.
1517 *
1518 * We also may need to enforce configured max-bio-bvecs limits.
1519 *
1520 * As long as the BIO is empty we have to allow at least one bvec,
1521 * regardless of size and offset, so no need to ask lower levels.
1522 */
1523 int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec)
1524 {
1525 struct drbd_device *device = (struct drbd_device *) q->queuedata;
1526 unsigned int bio_size = bvm->bi_size;
1527 int limit = DRBD_MAX_BIO_SIZE;
1528 int backing_limit;
1529
1530 if (bio_size && get_ldev(device)) {
1531 unsigned int max_hw_sectors = queue_max_hw_sectors(q);
1532 struct request_queue * const b =
1533 device->ldev->backing_bdev->bd_disk->queue;
1534 if (b->merge_bvec_fn) {
1535 bvm->bi_bdev = device->ldev->backing_bdev;
1536 backing_limit = b->merge_bvec_fn(b, bvm, bvec);
1537 limit = min(limit, backing_limit);
1538 }
1539 put_ldev(device);
1540 if ((limit >> 9) > max_hw_sectors)
1541 limit = max_hw_sectors << 9;
1542 }
1543 return limit;
1544 }
1545
1546 void request_timer_fn(unsigned long data)
1547 {
1548 struct drbd_device *device = (struct drbd_device *) data;
1549 struct drbd_connection *connection = first_peer_device(device)->connection;
1550 struct drbd_request *req_read, *req_write, *req_peer; /* oldest request */
1551 struct net_conf *nc;
1552 unsigned long oldest_submit_jif;
1553 unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */
1554 unsigned long now;
1555
1556 rcu_read_lock();
1557 nc = rcu_dereference(connection->net_conf);
1558 if (nc && device->state.conn >= C_WF_REPORT_PARAMS)
1559 ent = nc->timeout * HZ/10 * nc->ko_count;
1560
1561 if (get_ldev(device)) { /* implicit state.disk >= D_INCONSISTENT */
1562 dt = rcu_dereference(device->ldev->disk_conf)->disk_timeout * HZ / 10;
1563 put_ldev(device);
1564 }
1565 rcu_read_unlock();
1566
1567 et = min_not_zero(dt, ent);
1568
1569 if (!et)
1570 return; /* Recurring timer stopped */
1571
1572 now = jiffies;
1573 nt = now + et;
1574
1575 spin_lock_irq(&device->resource->req_lock);
1576 req_read = list_first_entry_or_null(&device->pending_completion[0], struct drbd_request, req_pending_local);
1577 req_write = list_first_entry_or_null(&device->pending_completion[1], struct drbd_request, req_pending_local);
1578 req_peer = connection->req_not_net_done;
1579 /* maybe the oldest request waiting for the peer is in fact still
1580 * blocking in tcp sendmsg */
1581 if (!req_peer && connection->req_next && connection->req_next->pre_send_jif)
1582 req_peer = connection->req_next;
1583
1584 /* evaluate the oldest peer request only in one timer! */
1585 if (req_peer && req_peer->device != device)
1586 req_peer = NULL;
1587
1588 /* do we have something to evaluate? */
1589 if (req_peer == NULL && req_write == NULL && req_read == NULL)
1590 goto out;
1591
1592 oldest_submit_jif =
1593 (req_write && req_read)
1594 ? ( time_before(req_write->pre_submit_jif, req_read->pre_submit_jif)
1595 ? req_write->pre_submit_jif : req_read->pre_submit_jif )
1596 : req_write ? req_write->pre_submit_jif
1597 : req_read ? req_read->pre_submit_jif : now;
1598
1599 /* The request is considered timed out, if
1600 * - we have some effective timeout from the configuration,
1601 * with above state restrictions applied,
1602 * - the oldest request is waiting for a response from the network
1603 * resp. the local disk,
1604 * - the oldest request is in fact older than the effective timeout,
1605 * - the connection was established (resp. disk was attached)
1606 * for longer than the timeout already.
1607 * Note that for 32bit jiffies and very stable connections/disks,
1608 * we may have a wrap around, which is catched by
1609 * !time_in_range(now, last_..._jif, last_..._jif + timeout).
1610 *
1611 * Side effect: once per 32bit wrap-around interval, which means every
1612 * ~198 days with 250 HZ, we have a window where the timeout would need
1613 * to expire twice (worst case) to become effective. Good enough.
1614 */
1615 if (ent && req_peer &&
1616 time_after(now, req_peer->pre_send_jif + ent) &&
1617 !time_in_range(now, connection->last_reconnect_jif, connection->last_reconnect_jif + ent)) {
1618 drbd_warn(device, "Remote failed to finish a request within ko-count * timeout\n");
1619 _conn_request_state(connection, NS(conn, C_TIMEOUT), CS_VERBOSE | CS_HARD);
1620 }
1621 if (dt && oldest_submit_jif != now &&
1622 time_after(now, oldest_submit_jif + dt) &&
1623 !time_in_range(now, device->last_reattach_jif, device->last_reattach_jif + dt)) {
1624 drbd_warn(device, "Local backing device failed to meet the disk-timeout\n");
1625 __drbd_chk_io_error(device, DRBD_FORCE_DETACH);
1626 }
1627
1628 /* Reschedule timer for the nearest not already expired timeout.
1629 * Fallback to now + min(effective network timeout, disk timeout). */
1630 ent = (ent && req_peer && time_before(now, req_peer->pre_send_jif + ent))
1631 ? req_peer->pre_send_jif + ent : now + et;
1632 dt = (dt && oldest_submit_jif != now && time_before(now, oldest_submit_jif + dt))
1633 ? oldest_submit_jif + dt : now + et;
1634 nt = time_before(ent, dt) ? ent : dt;
1635 out:
1636 spin_unlock_irq(&device->resource->req_lock);
1637 mod_timer(&device->request_timer, nt);
1638 }
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