4 This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
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>.
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)
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.
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.
26 #include <linux/module.h>
28 #include <linux/slab.h>
29 #include <linux/drbd.h>
34 static bool drbd_may_do_local_read(struct drbd_device
*device
, sector_t sector
, int size
);
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
)
39 generic_start_io_acct(bio_data_dir(req
->master_bio
), req
->i
.size
>> 9,
40 &device
->vdisk
->part0
);
43 /* Update disk stats when completing request upwards */
44 static void _drbd_end_io_acct(struct drbd_device
*device
, struct drbd_request
*req
)
46 generic_end_io_acct(bio_data_dir(req
->master_bio
),
47 &device
->vdisk
->part0
, req
->start_jif
);
50 static struct drbd_request
*drbd_req_new(struct drbd_device
*device
, struct bio
*bio_src
)
52 struct drbd_request
*req
;
54 req
= mempool_alloc(drbd_request_mempool
, GFP_NOIO
);
57 memset(req
, 0, sizeof(*req
));
59 drbd_req_make_private_bio(req
, bio_src
);
60 req
->rq_state
= (bio_data_dir(bio_src
) == WRITE
? RQ_WRITE
: 0)
61 | (bio_op(bio_src
) == REQ_OP_WRITE_SAME
? RQ_WSAME
: 0)
62 | (bio_op(bio_src
) == REQ_OP_DISCARD
? RQ_UNMAP
: 0);
64 req
->master_bio
= bio_src
;
67 drbd_clear_interval(&req
->i
);
68 req
->i
.sector
= bio_src
->bi_iter
.bi_sector
;
69 req
->i
.size
= bio_src
->bi_iter
.bi_size
;
71 req
->i
.waiting
= false;
73 INIT_LIST_HEAD(&req
->tl_requests
);
74 INIT_LIST_HEAD(&req
->w
.list
);
75 INIT_LIST_HEAD(&req
->req_pending_master_completion
);
76 INIT_LIST_HEAD(&req
->req_pending_local
);
78 /* one reference to be put by __drbd_make_request */
79 atomic_set(&req
->completion_ref
, 1);
80 /* one kref as long as completion_ref > 0 */
81 kref_init(&req
->kref
);
85 static void drbd_remove_request_interval(struct rb_root
*root
,
86 struct drbd_request
*req
)
88 struct drbd_device
*device
= req
->device
;
89 struct drbd_interval
*i
= &req
->i
;
91 drbd_remove_interval(root
, i
);
93 /* Wake up any processes waiting for this request to complete. */
95 wake_up(&device
->misc_wait
);
98 void drbd_req_destroy(struct kref
*kref
)
100 struct drbd_request
*req
= container_of(kref
, struct drbd_request
, kref
);
101 struct drbd_device
*device
= req
->device
;
102 const unsigned s
= req
->rq_state
;
104 if ((req
->master_bio
&& !(s
& RQ_POSTPONED
)) ||
105 atomic_read(&req
->completion_ref
) ||
106 (s
& RQ_LOCAL_PENDING
) ||
107 ((s
& RQ_NET_MASK
) && !(s
& RQ_NET_DONE
))) {
108 drbd_err(device
, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n",
109 s
, atomic_read(&req
->completion_ref
));
113 /* If called from mod_rq_state (expected normal case) or
114 * drbd_send_and_submit (the less likely normal path), this holds the
115 * req_lock, and req->tl_requests will typicaly be on ->transfer_log,
116 * though it may be still empty (never added to the transfer log).
118 * If called from do_retry(), we do NOT hold the req_lock, but we are
119 * still allowed to unconditionally list_del(&req->tl_requests),
120 * because it will be on a local on-stack list only. */
121 list_del_init(&req
->tl_requests
);
123 /* finally remove the request from the conflict detection
124 * respective block_id verification interval tree. */
125 if (!drbd_interval_empty(&req
->i
)) {
126 struct rb_root
*root
;
129 root
= &device
->write_requests
;
131 root
= &device
->read_requests
;
132 drbd_remove_request_interval(root
, req
);
133 } else if (s
& (RQ_NET_MASK
& ~RQ_NET_DONE
) && req
->i
.size
!= 0)
134 drbd_err(device
, "drbd_req_destroy: Logic BUG: interval empty, but: rq_state=0x%x, sect=%llu, size=%u\n",
135 s
, (unsigned long long)req
->i
.sector
, req
->i
.size
);
137 /* if it was a write, we may have to set the corresponding
138 * bit(s) out-of-sync first. If it had a local part, we need to
139 * release the reference to the activity log. */
141 /* Set out-of-sync unless both OK flags are set
142 * (local only or remote failed).
143 * Other places where we set out-of-sync:
144 * READ with local io-error */
146 /* There is a special case:
147 * we may notice late that IO was suspended,
148 * and postpone, or schedule for retry, a write,
149 * before it even was submitted or sent.
150 * In that case we do not want to touch the bitmap at all.
152 if ((s
& (RQ_POSTPONED
|RQ_LOCAL_MASK
|RQ_NET_MASK
)) != RQ_POSTPONED
) {
153 if (!(s
& RQ_NET_OK
) || !(s
& RQ_LOCAL_OK
))
154 drbd_set_out_of_sync(device
, req
->i
.sector
, req
->i
.size
);
156 if ((s
& RQ_NET_OK
) && (s
& RQ_LOCAL_OK
) && (s
& RQ_NET_SIS
))
157 drbd_set_in_sync(device
, req
->i
.sector
, req
->i
.size
);
160 /* one might be tempted to move the drbd_al_complete_io
161 * to the local io completion callback drbd_request_endio.
162 * but, if this was a mirror write, we may only
163 * drbd_al_complete_io after this is RQ_NET_DONE,
164 * otherwise the extent could be dropped from the al
165 * before it has actually been written on the peer.
166 * if we crash before our peer knows about the request,
167 * but after the extent has been dropped from the al,
168 * we would forget to resync the corresponding extent.
170 if (s
& RQ_IN_ACT_LOG
) {
171 if (get_ldev_if_state(device
, D_FAILED
)) {
172 drbd_al_complete_io(device
, &req
->i
);
174 } else if (__ratelimit(&drbd_ratelimit_state
)) {
175 drbd_warn(device
, "Should have called drbd_al_complete_io(, %llu, %u), "
176 "but my Disk seems to have failed :(\n",
177 (unsigned long long) req
->i
.sector
, req
->i
.size
);
182 mempool_free(req
, drbd_request_mempool
);
185 static void wake_all_senders(struct drbd_connection
*connection
)
187 wake_up(&connection
->sender_work
.q_wait
);
190 /* must hold resource->req_lock */
191 void start_new_tl_epoch(struct drbd_connection
*connection
)
193 /* no point closing an epoch, if it is empty, anyways. */
194 if (connection
->current_tle_writes
== 0)
197 connection
->current_tle_writes
= 0;
198 atomic_inc(&connection
->current_tle_nr
);
199 wake_all_senders(connection
);
202 void complete_master_bio(struct drbd_device
*device
,
203 struct bio_and_error
*m
)
205 m
->bio
->bi_error
= m
->error
;
211 /* Helper for __req_mod().
212 * Set m->bio to the master bio, if it is fit to be completed,
213 * or leave it alone (it is initialized to NULL in __req_mod),
214 * if it has already been completed, or cannot be completed yet.
215 * If m->bio is set, the error status to be returned is placed in m->error.
218 void drbd_req_complete(struct drbd_request
*req
, struct bio_and_error
*m
)
220 const unsigned s
= req
->rq_state
;
221 struct drbd_device
*device
= req
->device
;
224 /* we must not complete the master bio, while it is
225 * still being processed by _drbd_send_zc_bio (drbd_send_dblock)
226 * not yet acknowledged by the peer
227 * not yet completed by the local io subsystem
228 * these flags may get cleared in any order by
231 * the bio_endio completion callbacks.
233 if ((s
& RQ_LOCAL_PENDING
&& !(s
& RQ_LOCAL_ABORTED
)) ||
234 (s
& RQ_NET_QUEUED
) || (s
& RQ_NET_PENDING
) ||
235 (s
& RQ_COMPLETION_SUSP
)) {
236 drbd_err(device
, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s
);
240 if (!req
->master_bio
) {
241 drbd_err(device
, "drbd_req_complete: Logic BUG, master_bio == NULL!\n");
246 * figure out whether to report success or failure.
248 * report success when at least one of the operations succeeded.
249 * or, to put the other way,
250 * only report failure, when both operations failed.
252 * what to do about the failures is handled elsewhere.
253 * what we need to do here is just: complete the master_bio.
255 * local completion error, if any, has been stored as ERR_PTR
256 * in private_bio within drbd_request_endio.
258 ok
= (s
& RQ_LOCAL_OK
) || (s
& RQ_NET_OK
);
259 error
= PTR_ERR(req
->private_bio
);
261 /* Before we can signal completion to the upper layers,
262 * we may need to close the current transfer log epoch.
263 * We are within the request lock, so we can simply compare
264 * the request epoch number with the current transfer log
265 * epoch number. If they match, increase the current_tle_nr,
266 * and reset the transfer log epoch write_cnt.
268 if (op_is_write(bio_op(req
->master_bio
)) &&
269 req
->epoch
== atomic_read(&first_peer_device(device
)->connection
->current_tle_nr
))
270 start_new_tl_epoch(first_peer_device(device
)->connection
);
272 /* Update disk stats */
273 _drbd_end_io_acct(device
, req
);
276 * have it be pushed back to the retry work queue,
277 * so it will re-enter __drbd_make_request(),
278 * and be re-assigned to a suitable local or remote path,
279 * or failed if we do not have access to good data anymore.
281 * Unless it was failed early by __drbd_make_request(),
282 * because no path was available, in which case
283 * it was not even added to the transfer_log.
285 * read-ahead may fail, and will not be retried.
287 * WRITE should have used all available paths already.
290 bio_op(req
->master_bio
) == REQ_OP_READ
&&
291 !(req
->master_bio
->bi_opf
& REQ_RAHEAD
) &&
292 !list_empty(&req
->tl_requests
))
293 req
->rq_state
|= RQ_POSTPONED
;
295 if (!(req
->rq_state
& RQ_POSTPONED
)) {
296 m
->error
= ok
? 0 : (error
?: -EIO
);
297 m
->bio
= req
->master_bio
;
298 req
->master_bio
= NULL
;
299 /* We leave it in the tree, to be able to verify later
300 * write-acks in protocol != C during resync.
301 * But we mark it as "complete", so it won't be counted as
302 * conflict in a multi-primary setup. */
303 req
->i
.completed
= true;
307 wake_up(&device
->misc_wait
);
309 /* Either we are about to complete to upper layers,
310 * or we will restart this request.
311 * In either case, the request object will be destroyed soon,
312 * so better remove it from all lists. */
313 list_del_init(&req
->req_pending_master_completion
);
316 /* still holds resource->req_lock */
317 static int drbd_req_put_completion_ref(struct drbd_request
*req
, struct bio_and_error
*m
, int put
)
319 struct drbd_device
*device
= req
->device
;
320 D_ASSERT(device
, m
|| (req
->rq_state
& RQ_POSTPONED
));
322 if (!atomic_sub_and_test(put
, &req
->completion_ref
))
325 drbd_req_complete(req
, m
);
327 if (req
->rq_state
& RQ_POSTPONED
) {
328 /* don't destroy the req object just yet,
329 * but queue it for retry */
330 drbd_restart_request(req
);
337 static void set_if_null_req_next(struct drbd_peer_device
*peer_device
, struct drbd_request
*req
)
339 struct drbd_connection
*connection
= peer_device
? peer_device
->connection
: NULL
;
342 if (connection
->req_next
== NULL
)
343 connection
->req_next
= req
;
346 static void advance_conn_req_next(struct drbd_peer_device
*peer_device
, struct drbd_request
*req
)
348 struct drbd_connection
*connection
= peer_device
? peer_device
->connection
: NULL
;
351 if (connection
->req_next
!= req
)
353 list_for_each_entry_continue(req
, &connection
->transfer_log
, tl_requests
) {
354 const unsigned s
= req
->rq_state
;
355 if (s
& RQ_NET_QUEUED
)
358 if (&req
->tl_requests
== &connection
->transfer_log
)
360 connection
->req_next
= req
;
363 static void set_if_null_req_ack_pending(struct drbd_peer_device
*peer_device
, struct drbd_request
*req
)
365 struct drbd_connection
*connection
= peer_device
? peer_device
->connection
: NULL
;
368 if (connection
->req_ack_pending
== NULL
)
369 connection
->req_ack_pending
= req
;
372 static void advance_conn_req_ack_pending(struct drbd_peer_device
*peer_device
, struct drbd_request
*req
)
374 struct drbd_connection
*connection
= peer_device
? peer_device
->connection
: NULL
;
377 if (connection
->req_ack_pending
!= req
)
379 list_for_each_entry_continue(req
, &connection
->transfer_log
, tl_requests
) {
380 const unsigned s
= req
->rq_state
;
381 if ((s
& RQ_NET_SENT
) && (s
& RQ_NET_PENDING
))
384 if (&req
->tl_requests
== &connection
->transfer_log
)
386 connection
->req_ack_pending
= req
;
389 static void set_if_null_req_not_net_done(struct drbd_peer_device
*peer_device
, struct drbd_request
*req
)
391 struct drbd_connection
*connection
= peer_device
? peer_device
->connection
: NULL
;
394 if (connection
->req_not_net_done
== NULL
)
395 connection
->req_not_net_done
= req
;
398 static void advance_conn_req_not_net_done(struct drbd_peer_device
*peer_device
, struct drbd_request
*req
)
400 struct drbd_connection
*connection
= peer_device
? peer_device
->connection
: NULL
;
403 if (connection
->req_not_net_done
!= req
)
405 list_for_each_entry_continue(req
, &connection
->transfer_log
, tl_requests
) {
406 const unsigned s
= req
->rq_state
;
407 if ((s
& RQ_NET_SENT
) && !(s
& RQ_NET_DONE
))
410 if (&req
->tl_requests
== &connection
->transfer_log
)
412 connection
->req_not_net_done
= req
;
415 /* I'd like this to be the only place that manipulates
416 * req->completion_ref and req->kref. */
417 static void mod_rq_state(struct drbd_request
*req
, struct bio_and_error
*m
,
420 struct drbd_device
*device
= req
->device
;
421 struct drbd_peer_device
*peer_device
= first_peer_device(device
);
422 unsigned s
= req
->rq_state
;
425 if (drbd_suspended(device
) && !((s
| clear
) & RQ_COMPLETION_SUSP
))
426 set
|= RQ_COMPLETION_SUSP
;
430 req
->rq_state
&= ~clear
;
431 req
->rq_state
|= set
;
434 if (req
->rq_state
== s
)
437 /* intent: get references */
439 kref_get(&req
->kref
);
441 if (!(s
& RQ_LOCAL_PENDING
) && (set
& RQ_LOCAL_PENDING
))
442 atomic_inc(&req
->completion_ref
);
444 if (!(s
& RQ_NET_PENDING
) && (set
& RQ_NET_PENDING
)) {
445 inc_ap_pending(device
);
446 atomic_inc(&req
->completion_ref
);
449 if (!(s
& RQ_NET_QUEUED
) && (set
& RQ_NET_QUEUED
)) {
450 atomic_inc(&req
->completion_ref
);
451 set_if_null_req_next(peer_device
, req
);
454 if (!(s
& RQ_EXP_BARR_ACK
) && (set
& RQ_EXP_BARR_ACK
))
455 kref_get(&req
->kref
); /* wait for the DONE */
457 if (!(s
& RQ_NET_SENT
) && (set
& RQ_NET_SENT
)) {
458 /* potentially already completed in the ack_receiver thread */
459 if (!(s
& RQ_NET_DONE
)) {
460 atomic_add(req
->i
.size
>> 9, &device
->ap_in_flight
);
461 set_if_null_req_not_net_done(peer_device
, req
);
463 if (req
->rq_state
& RQ_NET_PENDING
)
464 set_if_null_req_ack_pending(peer_device
, req
);
467 if (!(s
& RQ_COMPLETION_SUSP
) && (set
& RQ_COMPLETION_SUSP
))
468 atomic_inc(&req
->completion_ref
);
470 /* progress: put references */
472 if ((s
& RQ_COMPLETION_SUSP
) && (clear
& RQ_COMPLETION_SUSP
))
475 if (!(s
& RQ_LOCAL_ABORTED
) && (set
& RQ_LOCAL_ABORTED
)) {
476 D_ASSERT(device
, req
->rq_state
& RQ_LOCAL_PENDING
);
480 if ((s
& RQ_LOCAL_PENDING
) && (clear
& RQ_LOCAL_PENDING
)) {
481 if (req
->rq_state
& RQ_LOCAL_ABORTED
)
482 kref_put(&req
->kref
, drbd_req_destroy
);
485 list_del_init(&req
->req_pending_local
);
488 if ((s
& RQ_NET_PENDING
) && (clear
& RQ_NET_PENDING
)) {
489 dec_ap_pending(device
);
491 req
->acked_jif
= jiffies
;
492 advance_conn_req_ack_pending(peer_device
, req
);
495 if ((s
& RQ_NET_QUEUED
) && (clear
& RQ_NET_QUEUED
)) {
497 advance_conn_req_next(peer_device
, req
);
500 if (!(s
& RQ_NET_DONE
) && (set
& RQ_NET_DONE
)) {
502 atomic_sub(req
->i
.size
>> 9, &device
->ap_in_flight
);
503 if (s
& RQ_EXP_BARR_ACK
)
504 kref_put(&req
->kref
, drbd_req_destroy
);
505 req
->net_done_jif
= jiffies
;
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
);
515 /* potentially complete and destroy */
517 /* If we made progress, retry conflicting peer requests, if any. */
519 wake_up(&device
->misc_wait
);
522 if (drbd_req_put_completion_ref(req
, m
, c_put
))
523 kref_put(&req
->kref
, drbd_req_destroy
);
525 kref_put(&req
->kref
, drbd_req_destroy
);
529 static void drbd_report_io_error(struct drbd_device
*device
, struct drbd_request
*req
)
531 char b
[BDEVNAME_SIZE
];
533 if (!__ratelimit(&drbd_ratelimit_state
))
536 drbd_warn(device
, "local %s IO error sector %llu+%u on %s\n",
537 (req
->rq_state
& RQ_WRITE
) ? "WRITE" : "READ",
538 (unsigned long long)req
->i
.sector
,
540 bdevname(device
->ldev
->backing_bdev
, b
));
543 /* Helper for HANDED_OVER_TO_NETWORK.
544 * Is this a protocol A write (neither WRITE_ACK nor RECEIVE_ACK expected)?
545 * Is it also still "PENDING"?
546 * --> If so, clear PENDING and set NET_OK below.
547 * If it is a protocol A write, but not RQ_PENDING anymore, neg-ack was faster
548 * (and we must not set RQ_NET_OK) */
549 static inline bool is_pending_write_protocol_A(struct drbd_request
*req
)
551 return (req
->rq_state
&
552 (RQ_WRITE
|RQ_NET_PENDING
|RQ_EXP_WRITE_ACK
|RQ_EXP_RECEIVE_ACK
))
553 == (RQ_WRITE
|RQ_NET_PENDING
);
556 /* obviously this could be coded as many single functions
557 * instead of one huge switch,
558 * or by putting the code directly in the respective locations
559 * (as it has been before).
561 * but having it this way
562 * enforces that it is all in this one place, where it is easier to audit,
563 * it makes it obvious that whatever "event" "happens" to a request should
564 * happen "atomically" within the req_lock,
565 * and it enforces that we have to think in a very structured manner
566 * about the "events" that may happen to a request during its life time ...
568 int __req_mod(struct drbd_request
*req
, enum drbd_req_event what
,
569 struct bio_and_error
*m
)
571 struct drbd_device
*const device
= req
->device
;
572 struct drbd_peer_device
*const peer_device
= first_peer_device(device
);
573 struct drbd_connection
*const connection
= peer_device
? peer_device
->connection
: NULL
;
582 drbd_err(device
, "LOGIC BUG in %s:%u\n", __FILE__
, __LINE__
);
585 /* does not happen...
586 * initialization done in drbd_req_new
591 case TO_BE_SENT
: /* via network */
592 /* reached via __drbd_make_request
593 * and from w_read_retry_remote */
594 D_ASSERT(device
, !(req
->rq_state
& RQ_NET_MASK
));
596 nc
= rcu_dereference(connection
->net_conf
);
597 p
= nc
->wire_protocol
;
600 p
== DRBD_PROT_C
? RQ_EXP_WRITE_ACK
:
601 p
== DRBD_PROT_B
? RQ_EXP_RECEIVE_ACK
: 0;
602 mod_rq_state(req
, m
, 0, RQ_NET_PENDING
);
605 case TO_BE_SUBMITTED
: /* locally */
606 /* reached via __drbd_make_request */
607 D_ASSERT(device
, !(req
->rq_state
& RQ_LOCAL_MASK
));
608 mod_rq_state(req
, m
, 0, RQ_LOCAL_PENDING
);
612 if (req
->rq_state
& RQ_WRITE
)
613 device
->writ_cnt
+= req
->i
.size
>> 9;
615 device
->read_cnt
+= req
->i
.size
>> 9;
617 mod_rq_state(req
, m
, RQ_LOCAL_PENDING
,
618 RQ_LOCAL_COMPLETED
|RQ_LOCAL_OK
);
622 mod_rq_state(req
, m
, 0, RQ_LOCAL_ABORTED
);
625 case WRITE_COMPLETED_WITH_ERROR
:
626 drbd_report_io_error(device
, req
);
627 __drbd_chk_io_error(device
, DRBD_WRITE_ERROR
);
628 mod_rq_state(req
, m
, RQ_LOCAL_PENDING
, RQ_LOCAL_COMPLETED
);
631 case READ_COMPLETED_WITH_ERROR
:
632 drbd_set_out_of_sync(device
, req
->i
.sector
, req
->i
.size
);
633 drbd_report_io_error(device
, req
);
634 __drbd_chk_io_error(device
, DRBD_READ_ERROR
);
636 case READ_AHEAD_COMPLETED_WITH_ERROR
:
637 /* it is legal to fail read-ahead, no __drbd_chk_io_error in that case. */
638 mod_rq_state(req
, m
, RQ_LOCAL_PENDING
, RQ_LOCAL_COMPLETED
);
641 case DISCARD_COMPLETED_NOTSUPP
:
642 case DISCARD_COMPLETED_WITH_ERROR
:
643 /* I'd rather not detach from local disk just because it
644 * failed a REQ_DISCARD. */
645 mod_rq_state(req
, m
, RQ_LOCAL_PENDING
, RQ_LOCAL_COMPLETED
);
648 case QUEUE_FOR_NET_READ
:
651 * or target area marked as invalid,
652 * or just got an io-error. */
653 /* from __drbd_make_request
654 * or from bio_endio during read io-error recovery */
656 /* So we can verify the handle in the answer packet.
657 * Corresponding drbd_remove_request_interval is in
658 * drbd_req_complete() */
659 D_ASSERT(device
, drbd_interval_empty(&req
->i
));
660 drbd_insert_interval(&device
->read_requests
, &req
->i
);
662 set_bit(UNPLUG_REMOTE
, &device
->flags
);
664 D_ASSERT(device
, req
->rq_state
& RQ_NET_PENDING
);
665 D_ASSERT(device
, (req
->rq_state
& RQ_LOCAL_MASK
) == 0);
666 mod_rq_state(req
, m
, 0, RQ_NET_QUEUED
);
667 req
->w
.cb
= w_send_read_req
;
668 drbd_queue_work(&connection
->sender_work
,
672 case QUEUE_FOR_NET_WRITE
:
673 /* assert something? */
674 /* from __drbd_make_request only */
676 /* Corresponding drbd_remove_request_interval is in
677 * drbd_req_complete() */
678 D_ASSERT(device
, drbd_interval_empty(&req
->i
));
679 drbd_insert_interval(&device
->write_requests
, &req
->i
);
682 * In case the req ended up on the transfer log before being
683 * queued on the worker, it could lead to this request being
684 * missed during cleanup after connection loss.
685 * So we have to do both operations here,
686 * within the same lock that protects the transfer log.
688 * _req_add_to_epoch(req); this has to be after the
689 * _maybe_start_new_epoch(req); which happened in
690 * __drbd_make_request, because we now may set the bit
691 * again ourselves to close the current epoch.
693 * Add req to the (now) current epoch (barrier). */
695 /* otherwise we may lose an unplug, which may cause some remote
696 * io-scheduler timeout to expire, increasing maximum latency,
697 * hurting performance. */
698 set_bit(UNPLUG_REMOTE
, &device
->flags
);
700 /* queue work item to send data */
701 D_ASSERT(device
, req
->rq_state
& RQ_NET_PENDING
);
702 mod_rq_state(req
, m
, 0, RQ_NET_QUEUED
|RQ_EXP_BARR_ACK
);
703 req
->w
.cb
= w_send_dblock
;
704 drbd_queue_work(&connection
->sender_work
,
707 /* close the epoch, in case it outgrew the limit */
709 nc
= rcu_dereference(connection
->net_conf
);
710 p
= nc
->max_epoch_size
;
712 if (connection
->current_tle_writes
>= p
)
713 start_new_tl_epoch(connection
);
717 case QUEUE_FOR_SEND_OOS
:
718 mod_rq_state(req
, m
, 0, RQ_NET_QUEUED
);
719 req
->w
.cb
= w_send_out_of_sync
;
720 drbd_queue_work(&connection
->sender_work
,
724 case READ_RETRY_REMOTE_CANCELED
:
727 /* real cleanup will be done from tl_clear. just update flags
728 * so it is no longer marked as on the worker queue */
729 mod_rq_state(req
, m
, RQ_NET_QUEUED
, 0);
732 case HANDED_OVER_TO_NETWORK
:
733 /* assert something? */
734 if (is_pending_write_protocol_A(req
))
735 /* this is what is dangerous about protocol A:
736 * pretend it was successfully written on the peer. */
737 mod_rq_state(req
, m
, RQ_NET_QUEUED
|RQ_NET_PENDING
,
738 RQ_NET_SENT
|RQ_NET_OK
);
740 mod_rq_state(req
, m
, RQ_NET_QUEUED
, RQ_NET_SENT
);
741 /* It is still not yet RQ_NET_DONE until the
742 * corresponding epoch barrier got acked as well,
743 * so we know what to dirty on connection loss. */
746 case OOS_HANDED_TO_NETWORK
:
747 /* Was not set PENDING, no longer QUEUED, so is now DONE
748 * as far as this connection is concerned. */
749 mod_rq_state(req
, m
, RQ_NET_QUEUED
, RQ_NET_DONE
);
752 case CONNECTION_LOST_WHILE_PENDING
:
753 /* transfer log cleanup after connection loss */
755 RQ_NET_OK
|RQ_NET_PENDING
|RQ_COMPLETION_SUSP
,
759 case CONFLICT_RESOLVED
:
760 /* for superseded conflicting writes of multiple primaries,
761 * there is no need to keep anything in the tl, potential
762 * node crashes are covered by the activity log.
764 * If this request had been marked as RQ_POSTPONED before,
765 * it will actually not be completed, but "restarted",
766 * resubmitted from the retry worker context. */
767 D_ASSERT(device
, req
->rq_state
& RQ_NET_PENDING
);
768 D_ASSERT(device
, req
->rq_state
& RQ_EXP_WRITE_ACK
);
769 mod_rq_state(req
, m
, RQ_NET_PENDING
, RQ_NET_DONE
|RQ_NET_OK
);
772 case WRITE_ACKED_BY_PEER_AND_SIS
:
773 req
->rq_state
|= RQ_NET_SIS
;
774 case WRITE_ACKED_BY_PEER
:
775 /* Normal operation protocol C: successfully written on peer.
776 * During resync, even in protocol != C,
777 * we requested an explicit write ack anyways.
778 * Which means we cannot even assert anything here.
779 * Nothing more to do here.
780 * We want to keep the tl in place for all protocols, to cater
781 * for volatile write-back caches on lower level devices. */
783 case RECV_ACKED_BY_PEER
:
784 D_ASSERT(device
, req
->rq_state
& RQ_EXP_RECEIVE_ACK
);
785 /* protocol B; pretends to be successfully written on peer.
786 * see also notes above in HANDED_OVER_TO_NETWORK about
789 mod_rq_state(req
, m
, RQ_NET_PENDING
, RQ_NET_OK
);
793 D_ASSERT(device
, req
->rq_state
& RQ_EXP_WRITE_ACK
);
794 /* If this node has already detected the write conflict, the
795 * worker will be waiting on misc_wait. Wake it up once this
796 * request has completed locally.
798 D_ASSERT(device
, req
->rq_state
& RQ_NET_PENDING
);
799 req
->rq_state
|= RQ_POSTPONED
;
801 wake_up(&device
->misc_wait
);
802 /* Do not clear RQ_NET_PENDING. This request will make further
803 * progress via restart_conflicting_writes() or
804 * fail_postponed_requests(). Hopefully. */
808 mod_rq_state(req
, m
, RQ_NET_OK
|RQ_NET_PENDING
, 0);
811 case FAIL_FROZEN_DISK_IO
:
812 if (!(req
->rq_state
& RQ_LOCAL_COMPLETED
))
814 mod_rq_state(req
, m
, RQ_COMPLETION_SUSP
, 0);
817 case RESTART_FROZEN_DISK_IO
:
818 if (!(req
->rq_state
& RQ_LOCAL_COMPLETED
))
822 RQ_COMPLETION_SUSP
|RQ_LOCAL_COMPLETED
,
826 if (bio_data_dir(req
->master_bio
) == WRITE
)
829 get_ldev(device
); /* always succeeds in this call path */
830 req
->w
.cb
= w_restart_disk_io
;
831 drbd_queue_work(&connection
->sender_work
,
836 /* Simply complete (local only) READs. */
837 if (!(req
->rq_state
& RQ_WRITE
) && !req
->w
.cb
) {
838 mod_rq_state(req
, m
, RQ_COMPLETION_SUSP
, 0);
842 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK
843 before the connection loss (B&C only); only P_BARRIER_ACK
844 (or the local completion?) was missing when we suspended.
845 Throwing them out of the TL here by pretending we got a BARRIER_ACK.
846 During connection handshake, we ensure that the peer was not rebooted. */
847 if (!(req
->rq_state
& RQ_NET_OK
)) {
848 /* FIXME could this possibly be a req->dw.cb == w_send_out_of_sync?
849 * in that case we must not set RQ_NET_PENDING. */
851 mod_rq_state(req
, m
, RQ_COMPLETION_SUSP
, RQ_NET_QUEUED
|RQ_NET_PENDING
);
853 /* w.cb expected to be w_send_dblock, or w_send_read_req */
854 drbd_queue_work(&connection
->sender_work
,
856 rv
= req
->rq_state
& RQ_WRITE
? MR_WRITE
: MR_READ
;
857 } /* else: FIXME can this happen? */
860 /* else, fall through to BARRIER_ACKED */
863 /* barrier ack for READ requests does not make sense */
864 if (!(req
->rq_state
& RQ_WRITE
))
867 if (req
->rq_state
& RQ_NET_PENDING
) {
868 /* barrier came in before all requests were acked.
869 * this is bad, because if the connection is lost now,
870 * we won't be able to clean them up... */
871 drbd_err(device
, "FIXME (BARRIER_ACKED but pending)\n");
873 /* Allowed to complete requests, even while suspended.
874 * As this is called for all requests within a matching epoch,
875 * we need to filter, and only set RQ_NET_DONE for those that
876 * have actually been on the wire. */
877 mod_rq_state(req
, m
, RQ_COMPLETION_SUSP
,
878 (req
->rq_state
& RQ_NET_MASK
) ? RQ_NET_DONE
: 0);
882 D_ASSERT(device
, req
->rq_state
& RQ_NET_PENDING
);
883 mod_rq_state(req
, m
, RQ_NET_PENDING
, RQ_NET_OK
|RQ_NET_DONE
);
886 case QUEUE_AS_DRBD_BARRIER
:
887 start_new_tl_epoch(connection
);
888 mod_rq_state(req
, m
, 0, RQ_NET_OK
|RQ_NET_DONE
);
895 /* we may do a local read if:
896 * - we are consistent (of course),
897 * - or we are generally inconsistent,
898 * BUT we are still/already IN SYNC for this area.
899 * since size may be bigger than BM_BLOCK_SIZE,
900 * we may need to check several bits.
902 static bool drbd_may_do_local_read(struct drbd_device
*device
, sector_t sector
, int size
)
904 unsigned long sbnr
, ebnr
;
905 sector_t esector
, nr_sectors
;
907 if (device
->state
.disk
== D_UP_TO_DATE
)
909 if (device
->state
.disk
!= D_INCONSISTENT
)
911 esector
= sector
+ (size
>> 9) - 1;
912 nr_sectors
= drbd_get_capacity(device
->this_bdev
);
913 D_ASSERT(device
, sector
< nr_sectors
);
914 D_ASSERT(device
, esector
< nr_sectors
);
916 sbnr
= BM_SECT_TO_BIT(sector
);
917 ebnr
= BM_SECT_TO_BIT(esector
);
919 return drbd_bm_count_bits(device
, sbnr
, ebnr
) == 0;
922 static bool remote_due_to_read_balancing(struct drbd_device
*device
, sector_t sector
,
923 enum drbd_read_balancing rbm
)
925 struct backing_dev_info
*bdi
;
929 case RB_CONGESTED_REMOTE
:
930 bdi
= device
->ldev
->backing_bdev
->bd_disk
->queue
->backing_dev_info
;
931 return bdi_read_congested(bdi
);
932 case RB_LEAST_PENDING
:
933 return atomic_read(&device
->local_cnt
) >
934 atomic_read(&device
->ap_pending_cnt
) + atomic_read(&device
->rs_pending_cnt
);
935 case RB_32K_STRIPING
: /* stripe_shift = 15 */
936 case RB_64K_STRIPING
:
937 case RB_128K_STRIPING
:
938 case RB_256K_STRIPING
:
939 case RB_512K_STRIPING
:
940 case RB_1M_STRIPING
: /* stripe_shift = 20 */
941 stripe_shift
= (rbm
- RB_32K_STRIPING
+ 15);
942 return (sector
>> (stripe_shift
- 9)) & 1;
944 return test_and_change_bit(READ_BALANCE_RR
, &device
->flags
);
945 case RB_PREFER_REMOTE
:
947 case RB_PREFER_LOCAL
:
954 * complete_conflicting_writes - wait for any conflicting write requests
956 * The write_requests tree contains all active write requests which we
957 * currently know about. Wait for any requests to complete which conflict with
960 * Only way out: remove the conflicting intervals from the tree.
962 static void complete_conflicting_writes(struct drbd_request
*req
)
965 struct drbd_device
*device
= req
->device
;
966 struct drbd_interval
*i
;
967 sector_t sector
= req
->i
.sector
;
968 int size
= req
->i
.size
;
971 drbd_for_each_overlap(i
, &device
->write_requests
, sector
, size
) {
972 /* Ignore, if already completed to upper layers. */
975 /* Handle the first found overlap. After the schedule
976 * we have to restart the tree walk. */
982 /* Indicate to wake up device->misc_wait on progress. */
983 prepare_to_wait(&device
->misc_wait
, &wait
, TASK_UNINTERRUPTIBLE
);
985 spin_unlock_irq(&device
->resource
->req_lock
);
987 spin_lock_irq(&device
->resource
->req_lock
);
989 finish_wait(&device
->misc_wait
, &wait
);
992 /* called within req_lock */
993 static void maybe_pull_ahead(struct drbd_device
*device
)
995 struct drbd_connection
*connection
= first_peer_device(device
)->connection
;
997 bool congested
= false;
998 enum drbd_on_congestion on_congestion
;
1001 nc
= rcu_dereference(connection
->net_conf
);
1002 on_congestion
= nc
? nc
->on_congestion
: OC_BLOCK
;
1004 if (on_congestion
== OC_BLOCK
||
1005 connection
->agreed_pro_version
< 96)
1008 if (on_congestion
== OC_PULL_AHEAD
&& device
->state
.conn
== C_AHEAD
)
1009 return; /* nothing to do ... */
1011 /* If I don't even have good local storage, we can not reasonably try
1012 * to pull ahead of the peer. We also need the local reference to make
1013 * sure device->act_log is there.
1015 if (!get_ldev_if_state(device
, D_UP_TO_DATE
))
1018 if (nc
->cong_fill
&&
1019 atomic_read(&device
->ap_in_flight
) >= nc
->cong_fill
) {
1020 drbd_info(device
, "Congestion-fill threshold reached\n");
1024 if (device
->act_log
->used
>= nc
->cong_extents
) {
1025 drbd_info(device
, "Congestion-extents threshold reached\n");
1030 /* start a new epoch for non-mirrored writes */
1031 start_new_tl_epoch(first_peer_device(device
)->connection
);
1033 if (on_congestion
== OC_PULL_AHEAD
)
1034 _drbd_set_state(_NS(device
, conn
, C_AHEAD
), 0, NULL
);
1035 else /*nc->on_congestion == OC_DISCONNECT */
1036 _drbd_set_state(_NS(device
, conn
, C_DISCONNECTING
), 0, NULL
);
1041 /* If this returns false, and req->private_bio is still set,
1042 * this should be submitted locally.
1044 * If it returns false, but req->private_bio is not set,
1045 * we do not have access to good data :(
1047 * Otherwise, this destroys req->private_bio, if any,
1050 static bool do_remote_read(struct drbd_request
*req
)
1052 struct drbd_device
*device
= req
->device
;
1053 enum drbd_read_balancing rbm
;
1055 if (req
->private_bio
) {
1056 if (!drbd_may_do_local_read(device
,
1057 req
->i
.sector
, req
->i
.size
)) {
1058 bio_put(req
->private_bio
);
1059 req
->private_bio
= NULL
;
1064 if (device
->state
.pdsk
!= D_UP_TO_DATE
)
1067 if (req
->private_bio
== NULL
)
1070 /* TODO: improve read balancing decisions, take into account drbd
1071 * protocol, pending requests etc. */
1074 rbm
= rcu_dereference(device
->ldev
->disk_conf
)->read_balancing
;
1077 if (rbm
== RB_PREFER_LOCAL
&& req
->private_bio
)
1078 return false; /* submit locally */
1080 if (remote_due_to_read_balancing(device
, req
->i
.sector
, rbm
)) {
1081 if (req
->private_bio
) {
1082 bio_put(req
->private_bio
);
1083 req
->private_bio
= NULL
;
1092 bool drbd_should_do_remote(union drbd_dev_state s
)
1094 return s
.pdsk
== D_UP_TO_DATE
||
1095 (s
.pdsk
>= D_INCONSISTENT
&&
1096 s
.conn
>= C_WF_BITMAP_T
&&
1098 /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T.
1099 That is equivalent since before 96 IO was frozen in the C_WF_BITMAP*
1103 static bool drbd_should_send_out_of_sync(union drbd_dev_state s
)
1105 return s
.conn
== C_AHEAD
|| s
.conn
== C_WF_BITMAP_S
;
1106 /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary
1107 since we enter state C_AHEAD only if proto >= 96 */
1110 /* returns number of connections (== 1, for drbd 8.4)
1111 * expected to actually write this data,
1112 * which does NOT include those that we are L_AHEAD for. */
1113 static int drbd_process_write_request(struct drbd_request
*req
)
1115 struct drbd_device
*device
= req
->device
;
1116 int remote
, send_oos
;
1118 remote
= drbd_should_do_remote(device
->state
);
1119 send_oos
= drbd_should_send_out_of_sync(device
->state
);
1121 /* Need to replicate writes. Unless it is an empty flush,
1122 * which is better mapped to a DRBD P_BARRIER packet,
1123 * also for drbd wire protocol compatibility reasons.
1124 * If this was a flush, just start a new epoch.
1125 * Unless the current epoch was empty anyways, or we are not currently
1126 * replicating, in which case there is no point. */
1127 if (unlikely(req
->i
.size
== 0)) {
1128 /* The only size==0 bios we expect are empty flushes. */
1129 D_ASSERT(device
, req
->master_bio
->bi_opf
& REQ_PREFLUSH
);
1131 _req_mod(req
, QUEUE_AS_DRBD_BARRIER
);
1135 if (!remote
&& !send_oos
)
1138 D_ASSERT(device
, !(remote
&& send_oos
));
1141 _req_mod(req
, TO_BE_SENT
);
1142 _req_mod(req
, QUEUE_FOR_NET_WRITE
);
1143 } else if (drbd_set_out_of_sync(device
, req
->i
.sector
, req
->i
.size
))
1144 _req_mod(req
, QUEUE_FOR_SEND_OOS
);
1149 static void drbd_process_discard_req(struct drbd_request
*req
)
1151 int err
= drbd_issue_discard_or_zero_out(req
->device
,
1152 req
->i
.sector
, req
->i
.size
>> 9, true);
1155 req
->private_bio
->bi_error
= -EIO
;
1156 bio_endio(req
->private_bio
);
1160 drbd_submit_req_private_bio(struct drbd_request
*req
)
1162 struct drbd_device
*device
= req
->device
;
1163 struct bio
*bio
= req
->private_bio
;
1166 if (bio_op(bio
) != REQ_OP_READ
)
1167 type
= DRBD_FAULT_DT_WR
;
1168 else if (bio
->bi_opf
& REQ_RAHEAD
)
1169 type
= DRBD_FAULT_DT_RA
;
1171 type
= DRBD_FAULT_DT_RD
;
1173 bio
->bi_bdev
= device
->ldev
->backing_bdev
;
1175 /* State may have changed since we grabbed our reference on the
1176 * ->ldev member. Double check, and short-circuit to endio.
1177 * In case the last activity log transaction failed to get on
1178 * stable storage, and this is a WRITE, we may not even submit
1180 if (get_ldev(device
)) {
1181 if (drbd_insert_fault(device
, type
))
1183 else if (bio_op(bio
) == REQ_OP_DISCARD
)
1184 drbd_process_discard_req(req
);
1186 generic_make_request(bio
);
1192 static void drbd_queue_write(struct drbd_device
*device
, struct drbd_request
*req
)
1194 spin_lock_irq(&device
->resource
->req_lock
);
1195 list_add_tail(&req
->tl_requests
, &device
->submit
.writes
);
1196 list_add_tail(&req
->req_pending_master_completion
,
1197 &device
->pending_master_completion
[1 /* WRITE */]);
1198 spin_unlock_irq(&device
->resource
->req_lock
);
1199 queue_work(device
->submit
.wq
, &device
->submit
.worker
);
1200 /* do_submit() may sleep internally on al_wait, too */
1201 wake_up(&device
->al_wait
);
1204 /* returns the new drbd_request pointer, if the caller is expected to
1205 * drbd_send_and_submit() it (to save latency), or NULL if we queued the
1206 * request on the submitter thread.
1207 * Returns ERR_PTR(-ENOMEM) if we cannot allocate a drbd_request.
1209 static struct drbd_request
*
1210 drbd_request_prepare(struct drbd_device
*device
, struct bio
*bio
, unsigned long start_jif
)
1212 const int rw
= bio_data_dir(bio
);
1213 struct drbd_request
*req
;
1215 /* allocate outside of all locks; */
1216 req
= drbd_req_new(device
, bio
);
1219 /* only pass the error to the upper layers.
1220 * if user cannot handle io errors, that's not our business. */
1221 drbd_err(device
, "could not kmalloc() req\n");
1222 bio
->bi_error
= -ENOMEM
;
1224 return ERR_PTR(-ENOMEM
);
1226 req
->start_jif
= start_jif
;
1228 if (!get_ldev(device
)) {
1229 bio_put(req
->private_bio
);
1230 req
->private_bio
= NULL
;
1233 /* Update disk stats */
1234 _drbd_start_io_acct(device
, req
);
1236 /* process discards always from our submitter thread */
1237 if (bio_op(bio
) & REQ_OP_DISCARD
)
1238 goto queue_for_submitter_thread
;
1240 if (rw
== WRITE
&& req
->private_bio
&& req
->i
.size
1241 && !test_bit(AL_SUSPENDED
, &device
->flags
)) {
1242 if (!drbd_al_begin_io_fastpath(device
, &req
->i
))
1243 goto queue_for_submitter_thread
;
1244 req
->rq_state
|= RQ_IN_ACT_LOG
;
1245 req
->in_actlog_jif
= jiffies
;
1249 queue_for_submitter_thread
:
1250 atomic_inc(&device
->ap_actlog_cnt
);
1251 drbd_queue_write(device
, req
);
1255 /* Require at least one path to current data.
1256 * We don't want to allow writes on C_STANDALONE D_INCONSISTENT:
1257 * We would not allow to read what was written,
1258 * we would not have bumped the data generation uuids,
1259 * we would cause data divergence for all the wrong reasons.
1261 * If we don't see at least one D_UP_TO_DATE, we will fail this request,
1262 * which either returns EIO, or, if OND_SUSPEND_IO is set, suspends IO,
1263 * and queues for retry later.
1265 static bool may_do_writes(struct drbd_device
*device
)
1267 const union drbd_dev_state s
= device
->state
;
1268 return s
.disk
== D_UP_TO_DATE
|| s
.pdsk
== D_UP_TO_DATE
;
1271 static void drbd_send_and_submit(struct drbd_device
*device
, struct drbd_request
*req
)
1273 struct drbd_resource
*resource
= device
->resource
;
1274 const int rw
= bio_data_dir(req
->master_bio
);
1275 struct bio_and_error m
= { NULL
, };
1276 bool no_remote
= false;
1277 bool submit_private_bio
= false;
1279 spin_lock_irq(&resource
->req_lock
);
1281 /* This may temporarily give up the req_lock,
1282 * but will re-aquire it before it returns here.
1283 * Needs to be before the check on drbd_suspended() */
1284 complete_conflicting_writes(req
);
1285 /* no more giving up req_lock from now on! */
1287 /* check for congestion, and potentially stop sending
1288 * full data updates, but start sending "dirty bits" only. */
1289 maybe_pull_ahead(device
);
1293 if (drbd_suspended(device
)) {
1294 /* push back and retry: */
1295 req
->rq_state
|= RQ_POSTPONED
;
1296 if (req
->private_bio
) {
1297 bio_put(req
->private_bio
);
1298 req
->private_bio
= NULL
;
1304 /* We fail READ early, if we can not serve it.
1305 * We must do this before req is registered on any lists.
1306 * Otherwise, drbd_req_complete() will queue failed READ for retry. */
1308 if (!do_remote_read(req
) && !req
->private_bio
)
1312 /* which transfer log epoch does this belong to? */
1313 req
->epoch
= atomic_read(&first_peer_device(device
)->connection
->current_tle_nr
);
1315 /* no point in adding empty flushes to the transfer log,
1316 * they are mapped to drbd barriers already. */
1317 if (likely(req
->i
.size
!=0)) {
1319 first_peer_device(device
)->connection
->current_tle_writes
++;
1321 list_add_tail(&req
->tl_requests
, &first_peer_device(device
)->connection
->transfer_log
);
1325 if (req
->private_bio
&& !may_do_writes(device
)) {
1326 bio_put(req
->private_bio
);
1327 req
->private_bio
= NULL
;
1331 if (!drbd_process_write_request(req
))
1334 /* We either have a private_bio, or we can read from remote.
1335 * Otherwise we had done the goto nodata above. */
1336 if (req
->private_bio
== NULL
) {
1337 _req_mod(req
, TO_BE_SENT
);
1338 _req_mod(req
, QUEUE_FOR_NET_READ
);
1343 /* If it took the fast path in drbd_request_prepare, add it here.
1344 * The slow path has added it already. */
1345 if (list_empty(&req
->req_pending_master_completion
))
1346 list_add_tail(&req
->req_pending_master_completion
,
1347 &device
->pending_master_completion
[rw
== WRITE
]);
1348 if (req
->private_bio
) {
1349 /* needs to be marked within the same spinlock */
1350 req
->pre_submit_jif
= jiffies
;
1351 list_add_tail(&req
->req_pending_local
,
1352 &device
->pending_completion
[rw
== WRITE
]);
1353 _req_mod(req
, TO_BE_SUBMITTED
);
1354 /* but we need to give up the spinlock to submit */
1355 submit_private_bio
= true;
1356 } else if (no_remote
) {
1358 if (__ratelimit(&drbd_ratelimit_state
))
1359 drbd_err(device
, "IO ERROR: neither local nor remote data, sector %llu+%u\n",
1360 (unsigned long long)req
->i
.sector
, req
->i
.size
>> 9);
1361 /* A write may have been queued for send_oos, however.
1362 * So we can not simply free it, we must go through drbd_req_put_completion_ref() */
1366 if (drbd_req_put_completion_ref(req
, &m
, 1))
1367 kref_put(&req
->kref
, drbd_req_destroy
);
1368 spin_unlock_irq(&resource
->req_lock
);
1370 /* Even though above is a kref_put(), this is safe.
1371 * As long as we still need to submit our private bio,
1372 * we hold a completion ref, and the request cannot disappear.
1373 * If however this request did not even have a private bio to submit
1374 * (e.g. remote read), req may already be invalid now.
1375 * That's why we cannot check on req->private_bio. */
1376 if (submit_private_bio
)
1377 drbd_submit_req_private_bio(req
);
1379 complete_master_bio(device
, &m
);
1382 void __drbd_make_request(struct drbd_device
*device
, struct bio
*bio
, unsigned long start_jif
)
1384 struct drbd_request
*req
= drbd_request_prepare(device
, bio
, start_jif
);
1385 if (IS_ERR_OR_NULL(req
))
1387 drbd_send_and_submit(device
, req
);
1390 static void submit_fast_path(struct drbd_device
*device
, struct list_head
*incoming
)
1392 struct drbd_request
*req
, *tmp
;
1393 list_for_each_entry_safe(req
, tmp
, incoming
, tl_requests
) {
1394 const int rw
= bio_data_dir(req
->master_bio
);
1396 if (rw
== WRITE
/* rw != WRITE should not even end up here! */
1397 && req
->private_bio
&& req
->i
.size
1398 && !test_bit(AL_SUSPENDED
, &device
->flags
)) {
1399 if (!drbd_al_begin_io_fastpath(device
, &req
->i
))
1402 req
->rq_state
|= RQ_IN_ACT_LOG
;
1403 req
->in_actlog_jif
= jiffies
;
1404 atomic_dec(&device
->ap_actlog_cnt
);
1407 list_del_init(&req
->tl_requests
);
1408 drbd_send_and_submit(device
, req
);
1412 static bool prepare_al_transaction_nonblock(struct drbd_device
*device
,
1413 struct list_head
*incoming
,
1414 struct list_head
*pending
,
1415 struct list_head
*later
)
1417 struct drbd_request
*req
, *tmp
;
1421 spin_lock_irq(&device
->al_lock
);
1422 list_for_each_entry_safe(req
, tmp
, incoming
, tl_requests
) {
1423 err
= drbd_al_begin_io_nonblock(device
, &req
->i
);
1424 if (err
== -ENOBUFS
)
1429 list_move_tail(&req
->tl_requests
, later
);
1431 list_move_tail(&req
->tl_requests
, pending
);
1433 spin_unlock_irq(&device
->al_lock
);
1435 wake_up(&device
->al_wait
);
1436 return !list_empty(pending
);
1439 void send_and_submit_pending(struct drbd_device
*device
, struct list_head
*pending
)
1441 struct drbd_request
*req
, *tmp
;
1443 list_for_each_entry_safe(req
, tmp
, pending
, tl_requests
) {
1444 req
->rq_state
|= RQ_IN_ACT_LOG
;
1445 req
->in_actlog_jif
= jiffies
;
1446 atomic_dec(&device
->ap_actlog_cnt
);
1447 list_del_init(&req
->tl_requests
);
1448 drbd_send_and_submit(device
, req
);
1452 void do_submit(struct work_struct
*ws
)
1454 struct drbd_device
*device
= container_of(ws
, struct drbd_device
, submit
.worker
);
1455 LIST_HEAD(incoming
); /* from drbd_make_request() */
1456 LIST_HEAD(pending
); /* to be submitted after next AL-transaction commit */
1457 LIST_HEAD(busy
); /* blocked by resync requests */
1459 /* grab new incoming requests */
1460 spin_lock_irq(&device
->resource
->req_lock
);
1461 list_splice_tail_init(&device
->submit
.writes
, &incoming
);
1462 spin_unlock_irq(&device
->resource
->req_lock
);
1467 /* move used-to-be-busy back to front of incoming */
1468 list_splice_init(&busy
, &incoming
);
1469 submit_fast_path(device
, &incoming
);
1470 if (list_empty(&incoming
))
1474 prepare_to_wait(&device
->al_wait
, &wait
, TASK_UNINTERRUPTIBLE
);
1476 list_splice_init(&busy
, &incoming
);
1477 prepare_al_transaction_nonblock(device
, &incoming
, &pending
, &busy
);
1478 if (!list_empty(&pending
))
1483 /* If all currently "hot" activity log extents are kept busy by
1484 * incoming requests, we still must not totally starve new
1485 * requests to "cold" extents.
1486 * Something left on &incoming means there had not been
1487 * enough update slots available, and the activity log
1488 * has been marked as "starving".
1490 * Try again now, without looking for new requests,
1491 * effectively blocking all new requests until we made
1492 * at least _some_ progress with what we currently have.
1494 if (!list_empty(&incoming
))
1497 /* Nothing moved to pending, but nothing left
1498 * on incoming: all moved to busy!
1499 * Grab new and iterate. */
1500 spin_lock_irq(&device
->resource
->req_lock
);
1501 list_splice_tail_init(&device
->submit
.writes
, &incoming
);
1502 spin_unlock_irq(&device
->resource
->req_lock
);
1504 finish_wait(&device
->al_wait
, &wait
);
1506 /* If the transaction was full, before all incoming requests
1507 * had been processed, skip ahead to commit, and iterate
1508 * without splicing in more incoming requests from upper layers.
1510 * Else, if all incoming have been processed,
1511 * they have become either "pending" (to be submitted after
1512 * next transaction commit) or "busy" (blocked by resync).
1514 * Maybe more was queued, while we prepared the transaction?
1515 * Try to stuff those into this transaction as well.
1516 * Be strictly non-blocking here,
1517 * we already have something to commit.
1519 * Commit if we don't make any more progres.
1522 while (list_empty(&incoming
)) {
1523 LIST_HEAD(more_pending
);
1524 LIST_HEAD(more_incoming
);
1527 /* It is ok to look outside the lock,
1528 * it's only an optimization anyways */
1529 if (list_empty(&device
->submit
.writes
))
1532 spin_lock_irq(&device
->resource
->req_lock
);
1533 list_splice_tail_init(&device
->submit
.writes
, &more_incoming
);
1534 spin_unlock_irq(&device
->resource
->req_lock
);
1536 if (list_empty(&more_incoming
))
1539 made_progress
= prepare_al_transaction_nonblock(device
, &more_incoming
, &more_pending
, &busy
);
1541 list_splice_tail_init(&more_pending
, &pending
);
1542 list_splice_tail_init(&more_incoming
, &incoming
);
1547 drbd_al_begin_io_commit(device
);
1548 send_and_submit_pending(device
, &pending
);
1552 blk_qc_t
drbd_make_request(struct request_queue
*q
, struct bio
*bio
)
1554 struct drbd_device
*device
= (struct drbd_device
*) q
->queuedata
;
1555 unsigned long start_jif
;
1557 blk_queue_split(q
, &bio
, q
->bio_split
);
1559 start_jif
= jiffies
;
1562 * what we "blindly" assume:
1564 D_ASSERT(device
, IS_ALIGNED(bio
->bi_iter
.bi_size
, 512));
1567 __drbd_make_request(device
, bio
, start_jif
);
1568 return BLK_QC_T_NONE
;
1571 static bool net_timeout_reached(struct drbd_request
*net_req
,
1572 struct drbd_connection
*connection
,
1573 unsigned long now
, unsigned long ent
,
1574 unsigned int ko_count
, unsigned int timeout
)
1576 struct drbd_device
*device
= net_req
->device
;
1578 if (!time_after(now
, net_req
->pre_send_jif
+ ent
))
1581 if (time_in_range(now
, connection
->last_reconnect_jif
, connection
->last_reconnect_jif
+ ent
))
1584 if (net_req
->rq_state
& RQ_NET_PENDING
) {
1585 drbd_warn(device
, "Remote failed to finish a request within %ums > ko-count (%u) * timeout (%u * 0.1s)\n",
1586 jiffies_to_msecs(now
- net_req
->pre_send_jif
), ko_count
, timeout
);
1590 /* We received an ACK already (or are using protocol A),
1591 * but are waiting for the epoch closing barrier ack.
1592 * Check if we sent the barrier already. We should not blame the peer
1593 * for being unresponsive, if we did not even ask it yet. */
1594 if (net_req
->epoch
== connection
->send
.current_epoch_nr
) {
1596 "We did not send a P_BARRIER for %ums > ko-count (%u) * timeout (%u * 0.1s); drbd kernel thread blocked?\n",
1597 jiffies_to_msecs(now
- net_req
->pre_send_jif
), ko_count
, timeout
);
1601 /* Worst case: we may have been blocked for whatever reason, then
1602 * suddenly are able to send a lot of requests (and epoch separating
1603 * barriers) in quick succession.
1604 * The timestamp of the net_req may be much too old and not correspond
1605 * to the sending time of the relevant unack'ed barrier packet, so
1606 * would trigger a spurious timeout. The latest barrier packet may
1607 * have a too recent timestamp to trigger the timeout, potentially miss
1608 * a timeout. Right now we don't have a place to conveniently store
1610 * But in this particular situation, the application requests are still
1611 * completed to upper layers, DRBD should still "feel" responsive.
1612 * No need yet to kill this connection, it may still recover.
1613 * If not, eventually we will have queued enough into the network for
1614 * us to block. From that point of view, the timestamp of the last sent
1615 * barrier packet is relevant enough.
1617 if (time_after(now
, connection
->send
.last_sent_barrier_jif
+ ent
)) {
1618 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",
1619 connection
->send
.last_sent_barrier_jif
, now
,
1620 jiffies_to_msecs(now
- connection
->send
.last_sent_barrier_jif
), ko_count
, timeout
);
1626 /* A request is considered timed out, if
1627 * - we have some effective timeout from the configuration,
1628 * with some state restrictions applied,
1629 * - the oldest request is waiting for a response from the network
1630 * resp. the local disk,
1631 * - the oldest request is in fact older than the effective timeout,
1632 * - the connection was established (resp. disk was attached)
1633 * for longer than the timeout already.
1634 * Note that for 32bit jiffies and very stable connections/disks,
1635 * we may have a wrap around, which is catched by
1636 * !time_in_range(now, last_..._jif, last_..._jif + timeout).
1638 * Side effect: once per 32bit wrap-around interval, which means every
1639 * ~198 days with 250 HZ, we have a window where the timeout would need
1640 * to expire twice (worst case) to become effective. Good enough.
1643 void request_timer_fn(unsigned long data
)
1645 struct drbd_device
*device
= (struct drbd_device
*) data
;
1646 struct drbd_connection
*connection
= first_peer_device(device
)->connection
;
1647 struct drbd_request
*req_read
, *req_write
, *req_peer
; /* oldest request */
1648 struct net_conf
*nc
;
1649 unsigned long oldest_submit_jif
;
1650 unsigned long ent
= 0, dt
= 0, et
, nt
; /* effective timeout = ko_count * timeout */
1652 unsigned int ko_count
= 0, timeout
= 0;
1655 nc
= rcu_dereference(connection
->net_conf
);
1656 if (nc
&& device
->state
.conn
>= C_WF_REPORT_PARAMS
) {
1657 ko_count
= nc
->ko_count
;
1658 timeout
= nc
->timeout
;
1661 if (get_ldev(device
)) { /* implicit state.disk >= D_INCONSISTENT */
1662 dt
= rcu_dereference(device
->ldev
->disk_conf
)->disk_timeout
* HZ
/ 10;
1668 ent
= timeout
* HZ
/10 * ko_count
;
1669 et
= min_not_zero(dt
, ent
);
1672 return; /* Recurring timer stopped */
1677 spin_lock_irq(&device
->resource
->req_lock
);
1678 req_read
= list_first_entry_or_null(&device
->pending_completion
[0], struct drbd_request
, req_pending_local
);
1679 req_write
= list_first_entry_or_null(&device
->pending_completion
[1], struct drbd_request
, req_pending_local
);
1681 /* maybe the oldest request waiting for the peer is in fact still
1682 * blocking in tcp sendmsg. That's ok, though, that's handled via the
1683 * socket send timeout, requesting a ping, and bumping ko-count in
1684 * we_should_drop_the_connection().
1687 /* check the oldest request we did successfully sent,
1688 * but which is still waiting for an ACK. */
1689 req_peer
= connection
->req_ack_pending
;
1691 /* if we don't have such request (e.g. protocoll A)
1692 * check the oldest requests which is still waiting on its epoch
1693 * closing barrier ack. */
1695 req_peer
= connection
->req_not_net_done
;
1697 /* evaluate the oldest peer request only in one timer! */
1698 if (req_peer
&& req_peer
->device
!= device
)
1701 /* do we have something to evaluate? */
1702 if (req_peer
== NULL
&& req_write
== NULL
&& req_read
== NULL
)
1706 (req_write
&& req_read
)
1707 ? ( time_before(req_write
->pre_submit_jif
, req_read
->pre_submit_jif
)
1708 ? req_write
->pre_submit_jif
: req_read
->pre_submit_jif
)
1709 : req_write
? req_write
->pre_submit_jif
1710 : req_read
? req_read
->pre_submit_jif
: now
;
1712 if (ent
&& req_peer
&& net_timeout_reached(req_peer
, connection
, now
, ent
, ko_count
, timeout
))
1713 _conn_request_state(connection
, NS(conn
, C_TIMEOUT
), CS_VERBOSE
| CS_HARD
);
1715 if (dt
&& oldest_submit_jif
!= now
&&
1716 time_after(now
, oldest_submit_jif
+ dt
) &&
1717 !time_in_range(now
, device
->last_reattach_jif
, device
->last_reattach_jif
+ dt
)) {
1718 drbd_warn(device
, "Local backing device failed to meet the disk-timeout\n");
1719 __drbd_chk_io_error(device
, DRBD_FORCE_DETACH
);
1722 /* Reschedule timer for the nearest not already expired timeout.
1723 * Fallback to now + min(effective network timeout, disk timeout). */
1724 ent
= (ent
&& req_peer
&& time_before(now
, req_peer
->pre_send_jif
+ ent
))
1725 ? req_peer
->pre_send_jif
+ ent
: now
+ et
;
1726 dt
= (dt
&& oldest_submit_jif
!= now
&& time_before(now
, oldest_submit_jif
+ dt
))
1727 ? oldest_submit_jif
+ dt
: now
+ et
;
1728 nt
= time_before(ent
, dt
) ? ent
: dt
;
1730 spin_unlock_irq(&device
->resource
->req_lock
);
1731 mod_timer(&device
->request_timer
, nt
);