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 /* Update disk stats at start of I/O request */
35 static void _drbd_start_io_acct(struct drbd_conf
*mdev
, struct drbd_request
*req
, struct bio
*bio
)
37 const int rw
= bio_data_dir(bio
);
39 cpu
= part_stat_lock();
40 part_stat_inc(cpu
, &mdev
->vdisk
->part0
, ios
[rw
]);
41 part_stat_add(cpu
, &mdev
->vdisk
->part0
, sectors
[rw
], bio_sectors(bio
));
42 part_inc_in_flight(&mdev
->vdisk
->part0
, rw
);
46 /* Update disk stats when completing request upwards */
47 static void _drbd_end_io_acct(struct drbd_conf
*mdev
, struct drbd_request
*req
)
49 int rw
= bio_data_dir(req
->master_bio
);
50 unsigned long duration
= jiffies
- req
->start_time
;
52 cpu
= part_stat_lock();
53 part_stat_add(cpu
, &mdev
->vdisk
->part0
, ticks
[rw
], duration
);
54 part_round_stats(cpu
, &mdev
->vdisk
->part0
);
55 part_dec_in_flight(&mdev
->vdisk
->part0
, rw
);
59 static struct drbd_request
*drbd_req_new(struct drbd_conf
*mdev
,
62 struct drbd_request
*req
;
64 req
= mempool_alloc(drbd_request_mempool
, GFP_NOIO
);
68 drbd_req_make_private_bio(req
, bio_src
);
69 req
->rq_state
= bio_data_dir(bio_src
) == WRITE
? RQ_WRITE
: 0;
71 req
->master_bio
= bio_src
;
74 drbd_clear_interval(&req
->i
);
75 req
->i
.sector
= bio_src
->bi_sector
;
76 req
->i
.size
= bio_src
->bi_size
;
78 req
->i
.waiting
= false;
80 INIT_LIST_HEAD(&req
->tl_requests
);
81 INIT_LIST_HEAD(&req
->w
.list
);
86 static void drbd_req_free(struct drbd_request
*req
)
88 mempool_free(req
, drbd_request_mempool
);
91 /* rw is bio_data_dir(), only READ or WRITE */
92 static void _req_is_done(struct drbd_conf
*mdev
, struct drbd_request
*req
, const int rw
)
94 const unsigned long s
= req
->rq_state
;
96 /* remove it from the transfer log.
97 * well, only if it had been there in the first
98 * place... if it had not (local only or conflicting
99 * and never sent), it should still be "empty" as
100 * initialized in drbd_req_new(), so we can list_del() it
101 * here unconditionally */
102 list_del(&req
->tl_requests
);
104 /* if it was a write, we may have to set the corresponding
105 * bit(s) out-of-sync first. If it had a local part, we need to
106 * release the reference to the activity log. */
108 /* Set out-of-sync unless both OK flags are set
109 * (local only or remote failed).
110 * Other places where we set out-of-sync:
111 * READ with local io-error */
112 if (!(s
& RQ_NET_OK
) || !(s
& RQ_LOCAL_OK
))
113 drbd_set_out_of_sync(mdev
, req
->i
.sector
, req
->i
.size
);
115 if ((s
& RQ_NET_OK
) && (s
& RQ_LOCAL_OK
) && (s
& RQ_NET_SIS
))
116 drbd_set_in_sync(mdev
, req
->i
.sector
, req
->i
.size
);
118 /* one might be tempted to move the drbd_al_complete_io
119 * to the local io completion callback drbd_request_endio.
120 * but, if this was a mirror write, we may only
121 * drbd_al_complete_io after this is RQ_NET_DONE,
122 * otherwise the extent could be dropped from the al
123 * before it has actually been written on the peer.
124 * if we crash before our peer knows about the request,
125 * but after the extent has been dropped from the al,
126 * we would forget to resync the corresponding extent.
128 if (s
& RQ_LOCAL_MASK
) {
129 if (get_ldev_if_state(mdev
, D_FAILED
)) {
130 if (s
& RQ_IN_ACT_LOG
)
131 drbd_al_complete_io(mdev
, req
->i
.sector
);
133 } else if (__ratelimit(&drbd_ratelimit_state
)) {
134 dev_warn(DEV
, "Should have called drbd_al_complete_io(, %llu), "
135 "but my Disk seems to have failed :(\n",
136 (unsigned long long) req
->i
.sector
);
144 static void queue_barrier(struct drbd_conf
*mdev
)
146 struct drbd_tl_epoch
*b
;
148 /* We are within the req_lock. Once we queued the barrier for sending,
149 * we set the CREATE_BARRIER bit. It is cleared as soon as a new
150 * barrier/epoch object is added. This is the only place this bit is
151 * set. It indicates that the barrier for this epoch is already queued,
152 * and no new epoch has been created yet. */
153 if (test_bit(CREATE_BARRIER
, &mdev
->flags
))
156 b
= mdev
->tconn
->newest_tle
;
157 b
->w
.cb
= w_send_barrier
;
159 /* inc_ap_pending done here, so we won't
160 * get imbalanced on connection loss.
161 * dec_ap_pending will be done in got_BarrierAck
162 * or (on connection loss) in tl_clear. */
163 inc_ap_pending(mdev
);
164 drbd_queue_work(&mdev
->tconn
->data
.work
, &b
->w
);
165 set_bit(CREATE_BARRIER
, &mdev
->flags
);
168 static void _about_to_complete_local_write(struct drbd_conf
*mdev
,
169 struct drbd_request
*req
)
171 const unsigned long s
= req
->rq_state
;
173 /* Before we can signal completion to the upper layers,
174 * we may need to close the current epoch.
175 * We can skip this, if this request has not even been sent, because we
176 * did not have a fully established connection yet/anymore, during
177 * bitmap exchange, or while we are C_AHEAD due to congestion policy.
179 if (mdev
->state
.conn
>= C_CONNECTED
&&
180 (s
& RQ_NET_SENT
) != 0 &&
181 req
->epoch
== mdev
->tconn
->newest_tle
->br_number
)
185 void complete_master_bio(struct drbd_conf
*mdev
,
186 struct bio_and_error
*m
)
188 bio_endio(m
->bio
, m
->error
);
193 static void drbd_remove_request_interval(struct rb_root
*root
,
194 struct drbd_request
*req
)
196 struct drbd_conf
*mdev
= req
->w
.mdev
;
197 struct drbd_interval
*i
= &req
->i
;
199 drbd_remove_interval(root
, i
);
201 /* Wake up any processes waiting for this request to complete. */
203 wake_up(&mdev
->misc_wait
);
206 /* Helper for __req_mod().
207 * Set m->bio to the master bio, if it is fit to be completed,
208 * or leave it alone (it is initialized to NULL in __req_mod),
209 * if it has already been completed, or cannot be completed yet.
210 * If m->bio is set, the error status to be returned is placed in m->error.
212 void _req_may_be_done(struct drbd_request
*req
, struct bio_and_error
*m
)
214 const unsigned long s
= req
->rq_state
;
215 struct drbd_conf
*mdev
= req
->w
.mdev
;
216 /* only WRITES may end up here without a master bio (on barrier ack) */
217 int rw
= req
->master_bio
? bio_data_dir(req
->master_bio
) : WRITE
;
219 /* we must not complete the master bio, while it is
220 * still being processed by _drbd_send_zc_bio (drbd_send_dblock)
221 * not yet acknowledged by the peer
222 * not yet completed by the local io subsystem
223 * these flags may get cleared in any order by
226 * the bio_endio completion callbacks.
228 if (s
& RQ_LOCAL_PENDING
)
230 if (req
->i
.waiting
) {
231 /* Retry all conflicting peer requests. */
232 wake_up(&mdev
->misc_wait
);
234 if (s
& RQ_NET_QUEUED
)
236 if (s
& RQ_NET_PENDING
)
239 if (req
->master_bio
) {
240 /* this is DATA_RECEIVED (remote read)
241 * or protocol C P_WRITE_ACK
242 * or protocol B P_RECV_ACK
243 * or protocol A "HANDED_OVER_TO_NETWORK" (SendAck)
244 * or canceled or failed,
245 * or killed from the transfer log due to connection loss.
249 * figure out whether to report success or failure.
251 * report success when at least one of the operations succeeded.
252 * or, to put the other way,
253 * only report failure, when both operations failed.
255 * what to do about the failures is handled elsewhere.
256 * what we need to do here is just: complete the master_bio.
258 * local completion error, if any, has been stored as ERR_PTR
259 * in private_bio within drbd_request_endio.
261 int ok
= (s
& RQ_LOCAL_OK
) || (s
& RQ_NET_OK
);
262 int error
= PTR_ERR(req
->private_bio
);
264 /* remove the request from the conflict detection
265 * respective block_id verification hash */
266 if (!drbd_interval_empty(&req
->i
)) {
267 struct rb_root
*root
;
270 root
= &mdev
->write_requests
;
272 root
= &mdev
->read_requests
;
273 drbd_remove_request_interval(root
, req
);
274 } else if (!(s
& RQ_POSTPONED
))
275 D_ASSERT((s
& (RQ_NET_MASK
& ~RQ_NET_DONE
)) == 0);
277 /* for writes we need to do some extra housekeeping */
279 _about_to_complete_local_write(mdev
, req
);
281 /* Update disk stats */
282 _drbd_end_io_acct(mdev
, req
);
284 if (!(s
& RQ_POSTPONED
)) {
285 m
->error
= ok
? 0 : (error
?: -EIO
);
286 m
->bio
= req
->master_bio
;
288 req
->master_bio
= NULL
;
291 if ((s
& RQ_NET_MASK
) == 0 || (s
& RQ_NET_DONE
)) {
292 /* this is disconnected (local only) operation,
293 * or protocol C P_WRITE_ACK,
294 * or protocol A or B P_BARRIER_ACK,
295 * or killed from the transfer log due to connection loss. */
296 _req_is_done(mdev
, req
, rw
);
298 /* else: network part and not DONE yet. that is
299 * protocol A or B, barrier ack still pending... */
302 static void _req_may_be_done_not_susp(struct drbd_request
*req
, struct bio_and_error
*m
)
304 struct drbd_conf
*mdev
= req
->w
.mdev
;
306 if (!is_susp(mdev
->state
))
307 _req_may_be_done(req
, m
);
310 /* obviously this could be coded as many single functions
311 * instead of one huge switch,
312 * or by putting the code directly in the respective locations
313 * (as it has been before).
315 * but having it this way
316 * enforces that it is all in this one place, where it is easier to audit,
317 * it makes it obvious that whatever "event" "happens" to a request should
318 * happen "atomically" within the req_lock,
319 * and it enforces that we have to think in a very structured manner
320 * about the "events" that may happen to a request during its life time ...
322 int __req_mod(struct drbd_request
*req
, enum drbd_req_event what
,
323 struct bio_and_error
*m
)
325 struct drbd_conf
*mdev
= req
->w
.mdev
;
333 dev_err(DEV
, "LOGIC BUG in %s:%u\n", __FILE__
, __LINE__
);
336 /* does not happen...
337 * initialization done in drbd_req_new
342 case TO_BE_SENT
: /* via network */
343 /* reached via __drbd_make_request
344 * and from w_read_retry_remote */
345 D_ASSERT(!(req
->rq_state
& RQ_NET_MASK
));
346 req
->rq_state
|= RQ_NET_PENDING
;
347 inc_ap_pending(mdev
);
350 case TO_BE_SUBMITTED
: /* locally */
351 /* reached via __drbd_make_request */
352 D_ASSERT(!(req
->rq_state
& RQ_LOCAL_MASK
));
353 req
->rq_state
|= RQ_LOCAL_PENDING
;
357 if (bio_data_dir(req
->master_bio
) == WRITE
)
358 mdev
->writ_cnt
+= req
->i
.size
>> 9;
360 mdev
->read_cnt
+= req
->i
.size
>> 9;
362 req
->rq_state
|= (RQ_LOCAL_COMPLETED
|RQ_LOCAL_OK
);
363 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
365 _req_may_be_done_not_susp(req
, m
);
369 case WRITE_COMPLETED_WITH_ERROR
:
370 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
371 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
373 __drbd_chk_io_error(mdev
, false);
374 _req_may_be_done_not_susp(req
, m
);
378 case READ_AHEAD_COMPLETED_WITH_ERROR
:
379 /* it is legal to fail READA */
380 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
381 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
382 _req_may_be_done_not_susp(req
, m
);
386 case READ_COMPLETED_WITH_ERROR
:
387 drbd_set_out_of_sync(mdev
, req
->i
.sector
, req
->i
.size
);
389 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
390 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
392 D_ASSERT(!(req
->rq_state
& RQ_NET_MASK
));
394 __drbd_chk_io_error(mdev
, false);
397 /* no point in retrying if there is no good remote data,
398 * or we have no connection. */
399 if (mdev
->state
.pdsk
!= D_UP_TO_DATE
) {
400 _req_may_be_done_not_susp(req
, m
);
404 /* _req_mod(req,TO_BE_SENT); oops, recursion... */
405 req
->rq_state
|= RQ_NET_PENDING
;
406 inc_ap_pending(mdev
);
407 /* fall through: _req_mod(req,QUEUE_FOR_NET_READ); */
409 case QUEUE_FOR_NET_READ
:
410 /* READ or READA, and
412 * or target area marked as invalid,
413 * or just got an io-error. */
414 /* from __drbd_make_request
415 * or from bio_endio during read io-error recovery */
417 /* so we can verify the handle in the answer packet
418 * corresponding hlist_del is in _req_may_be_done() */
419 drbd_insert_interval(&mdev
->read_requests
, &req
->i
);
421 set_bit(UNPLUG_REMOTE
, &mdev
->flags
);
423 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
424 req
->rq_state
|= RQ_NET_QUEUED
;
425 req
->w
.cb
= (req
->rq_state
& RQ_LOCAL_MASK
)
426 ? w_read_retry_remote
428 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
431 case QUEUE_FOR_NET_WRITE
:
432 /* assert something? */
433 /* from __drbd_make_request only */
435 /* corresponding hlist_del is in _req_may_be_done() */
436 drbd_insert_interval(&mdev
->write_requests
, &req
->i
);
439 * In case the req ended up on the transfer log before being
440 * queued on the worker, it could lead to this request being
441 * missed during cleanup after connection loss.
442 * So we have to do both operations here,
443 * within the same lock that protects the transfer log.
445 * _req_add_to_epoch(req); this has to be after the
446 * _maybe_start_new_epoch(req); which happened in
447 * __drbd_make_request, because we now may set the bit
448 * again ourselves to close the current epoch.
450 * Add req to the (now) current epoch (barrier). */
452 /* otherwise we may lose an unplug, which may cause some remote
453 * io-scheduler timeout to expire, increasing maximum latency,
454 * hurting performance. */
455 set_bit(UNPLUG_REMOTE
, &mdev
->flags
);
457 /* see __drbd_make_request,
458 * just after it grabs the req_lock */
459 D_ASSERT(test_bit(CREATE_BARRIER
, &mdev
->flags
) == 0);
461 req
->epoch
= mdev
->tconn
->newest_tle
->br_number
;
463 /* increment size of current epoch */
464 mdev
->tconn
->newest_tle
->n_writes
++;
466 /* queue work item to send data */
467 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
468 req
->rq_state
|= RQ_NET_QUEUED
;
469 req
->w
.cb
= w_send_dblock
;
470 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
472 /* close the epoch, in case it outgrew the limit */
473 if (mdev
->tconn
->newest_tle
->n_writes
>= mdev
->tconn
->net_conf
->max_epoch_size
)
478 case QUEUE_FOR_SEND_OOS
:
479 req
->rq_state
|= RQ_NET_QUEUED
;
480 req
->w
.cb
= w_send_oos
;
481 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
484 case OOS_HANDED_TO_NETWORK
:
485 /* actually the same */
487 /* treat it the same */
489 /* real cleanup will be done from tl_clear. just update flags
490 * so it is no longer marked as on the worker queue */
491 req
->rq_state
&= ~RQ_NET_QUEUED
;
492 /* if we did it right, tl_clear should be scheduled only after
493 * this, so this should not be necessary! */
494 _req_may_be_done_not_susp(req
, m
);
497 case HANDED_OVER_TO_NETWORK
:
498 /* assert something? */
499 if (bio_data_dir(req
->master_bio
) == WRITE
)
500 atomic_add(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
502 if (bio_data_dir(req
->master_bio
) == WRITE
&&
503 mdev
->tconn
->net_conf
->wire_protocol
== DRBD_PROT_A
) {
504 /* this is what is dangerous about protocol A:
505 * pretend it was successfully written on the peer. */
506 if (req
->rq_state
& RQ_NET_PENDING
) {
507 dec_ap_pending(mdev
);
508 req
->rq_state
&= ~RQ_NET_PENDING
;
509 req
->rq_state
|= RQ_NET_OK
;
510 } /* else: neg-ack was faster... */
511 /* it is still not yet RQ_NET_DONE until the
512 * corresponding epoch barrier got acked as well,
513 * so we know what to dirty on connection loss */
515 req
->rq_state
&= ~RQ_NET_QUEUED
;
516 req
->rq_state
|= RQ_NET_SENT
;
517 /* because _drbd_send_zc_bio could sleep, and may want to
518 * dereference the bio even after the "WRITE_ACKED_BY_PEER" and
519 * "COMPLETED_OK" events came in, once we return from
520 * _drbd_send_zc_bio (drbd_send_dblock), we have to check
521 * whether it is done already, and end it. */
522 _req_may_be_done_not_susp(req
, m
);
525 case READ_RETRY_REMOTE_CANCELED
:
526 req
->rq_state
&= ~RQ_NET_QUEUED
;
527 /* fall through, in case we raced with drbd_disconnect */
528 case CONNECTION_LOST_WHILE_PENDING
:
529 /* transfer log cleanup after connection loss */
530 /* assert something? */
531 if (req
->rq_state
& RQ_NET_PENDING
)
532 dec_ap_pending(mdev
);
533 req
->rq_state
&= ~(RQ_NET_OK
|RQ_NET_PENDING
);
534 req
->rq_state
|= RQ_NET_DONE
;
535 if (req
->rq_state
& RQ_NET_SENT
&& req
->rq_state
& RQ_WRITE
)
536 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
538 /* if it is still queued, we may not complete it here.
539 * it will be canceled soon. */
540 if (!(req
->rq_state
& RQ_NET_QUEUED
))
541 _req_may_be_done(req
, m
); /* Allowed while state.susp */
544 case WRITE_ACKED_BY_PEER_AND_SIS
:
545 req
->rq_state
|= RQ_NET_SIS
;
547 /* for discarded conflicting writes of multiple primaries,
548 * there is no need to keep anything in the tl, potential
549 * node crashes are covered by the activity log. */
550 req
->rq_state
|= RQ_NET_DONE
;
552 case WRITE_ACKED_BY_PEER
:
553 /* protocol C; successfully written on peer.
554 * Nothing to do here.
555 * We want to keep the tl in place for all protocols, to cater
556 * for volatile write-back caches on lower level devices.
558 * A barrier request is expected to have forced all prior
559 * requests onto stable storage, so completion of a barrier
560 * request could set NET_DONE right here, and not wait for the
561 * P_BARRIER_ACK, but that is an unnecessary optimization. */
563 /* this makes it effectively the same as for: */
564 case RECV_ACKED_BY_PEER
:
565 /* protocol B; pretends to be successfully written on peer.
566 * see also notes above in HANDED_OVER_TO_NETWORK about
568 req
->rq_state
|= RQ_NET_OK
;
569 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
570 dec_ap_pending(mdev
);
571 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
572 req
->rq_state
&= ~RQ_NET_PENDING
;
573 _req_may_be_done_not_susp(req
, m
);
578 * If this node has already detected the write conflict, the
579 * worker will be waiting on misc_wait. Wake it up once this
580 * request has completed locally.
582 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
583 req
->rq_state
|= RQ_POSTPONED
;
584 _req_may_be_done_not_susp(req
, m
);
588 /* assert something? */
589 if (req
->rq_state
& RQ_NET_PENDING
) {
590 dec_ap_pending(mdev
);
591 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
593 req
->rq_state
&= ~(RQ_NET_OK
|RQ_NET_PENDING
);
595 req
->rq_state
|= RQ_NET_DONE
;
596 _req_may_be_done_not_susp(req
, m
);
597 /* else: done by HANDED_OVER_TO_NETWORK */
600 case FAIL_FROZEN_DISK_IO
:
601 if (!(req
->rq_state
& RQ_LOCAL_COMPLETED
))
604 _req_may_be_done(req
, m
); /* Allowed while state.susp */
607 case RESTART_FROZEN_DISK_IO
:
608 if (!(req
->rq_state
& RQ_LOCAL_COMPLETED
))
611 req
->rq_state
&= ~RQ_LOCAL_COMPLETED
;
614 if (bio_data_dir(req
->master_bio
) == WRITE
)
618 req
->w
.cb
= w_restart_disk_io
;
619 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
623 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK
624 before the connection loss (B&C only); only P_BARRIER_ACK was missing.
625 Trowing them out of the TL here by pretending we got a BARRIER_ACK
626 We ensure that the peer was not rebooted */
627 if (!(req
->rq_state
& RQ_NET_OK
)) {
629 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
630 rv
= req
->rq_state
& RQ_WRITE
? MR_WRITE
: MR_READ
;
634 /* else, fall through to BARRIER_ACKED */
637 if (!(req
->rq_state
& RQ_WRITE
))
640 if (req
->rq_state
& RQ_NET_PENDING
) {
641 /* barrier came in before all requests have been acked.
642 * this is bad, because if the connection is lost now,
643 * we won't be able to clean them up... */
644 dev_err(DEV
, "FIXME (BARRIER_ACKED but pending)\n");
645 list_move(&req
->tl_requests
, &mdev
->tconn
->out_of_sequence_requests
);
647 if ((req
->rq_state
& RQ_NET_MASK
) != 0) {
648 req
->rq_state
|= RQ_NET_DONE
;
649 if (mdev
->tconn
->net_conf
->wire_protocol
== DRBD_PROT_A
)
650 atomic_sub(req
->i
.size
>>9, &mdev
->ap_in_flight
);
652 _req_may_be_done(req
, m
); /* Allowed while state.susp */
656 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
657 dec_ap_pending(mdev
);
658 req
->rq_state
&= ~RQ_NET_PENDING
;
659 req
->rq_state
|= (RQ_NET_OK
|RQ_NET_DONE
);
660 _req_may_be_done_not_susp(req
, m
);
667 /* we may do a local read if:
668 * - we are consistent (of course),
669 * - or we are generally inconsistent,
670 * BUT we are still/already IN SYNC for this area.
671 * since size may be bigger than BM_BLOCK_SIZE,
672 * we may need to check several bits.
674 static int drbd_may_do_local_read(struct drbd_conf
*mdev
, sector_t sector
, int size
)
676 unsigned long sbnr
, ebnr
;
677 sector_t esector
, nr_sectors
;
679 if (mdev
->state
.disk
== D_UP_TO_DATE
)
681 if (mdev
->state
.disk
!= D_INCONSISTENT
)
683 esector
= sector
+ (size
>> 9) - 1;
685 nr_sectors
= drbd_get_capacity(mdev
->this_bdev
);
686 D_ASSERT(sector
< nr_sectors
);
687 D_ASSERT(esector
< nr_sectors
);
689 sbnr
= BM_SECT_TO_BIT(sector
);
690 ebnr
= BM_SECT_TO_BIT(esector
);
692 return 0 == drbd_bm_count_bits(mdev
, sbnr
, ebnr
);
696 * complete_conflicting_writes - wait for any conflicting write requests
698 * The write_requests tree contains all active write requests which we
699 * currently know about. Wait for any requests to complete which conflict with
702 static int complete_conflicting_writes(struct drbd_conf
*mdev
,
703 sector_t sector
, int size
)
706 struct drbd_interval
*i
;
709 i
= drbd_find_overlap(&mdev
->write_requests
, sector
, size
);
712 err
= drbd_wait_misc(mdev
, i
);
718 int __drbd_make_request(struct drbd_conf
*mdev
, struct bio
*bio
, unsigned long start_time
)
720 const int rw
= bio_rw(bio
);
721 const int size
= bio
->bi_size
;
722 const sector_t sector
= bio
->bi_sector
;
723 struct drbd_tl_epoch
*b
= NULL
;
724 struct drbd_request
*req
;
725 int local
, remote
, send_oos
= 0;
729 /* allocate outside of all locks; */
730 req
= drbd_req_new(mdev
, bio
);
733 /* only pass the error to the upper layers.
734 * if user cannot handle io errors, that's not our business. */
735 dev_err(DEV
, "could not kmalloc() req\n");
736 bio_endio(bio
, -ENOMEM
);
739 req
->start_time
= start_time
;
741 local
= get_ldev(mdev
);
743 bio_put(req
->private_bio
); /* or we get a bio leak */
744 req
->private_bio
= NULL
;
751 if (!drbd_may_do_local_read(mdev
, sector
, size
)) {
752 /* we could kick the syncer to
753 * sync this extent asap, wait for
754 * it, then continue locally.
755 * Or just issue the request remotely.
758 bio_put(req
->private_bio
);
759 req
->private_bio
= NULL
;
763 remote
= !local
&& mdev
->state
.pdsk
>= D_UP_TO_DATE
;
766 /* If we have a disk, but a READA request is mapped to remote,
767 * we are R_PRIMARY, D_INCONSISTENT, SyncTarget.
768 * Just fail that READA request right here.
770 * THINK: maybe fail all READA when not local?
771 * or make this configurable...
772 * if network is slow, READA won't do any good.
774 if (rw
== READA
&& mdev
->state
.disk
>= D_INCONSISTENT
&& !local
) {
776 goto fail_and_free_req
;
779 /* For WRITES going to the local disk, grab a reference on the target
780 * extent. This waits for any resync activity in the corresponding
781 * resync extent to finish, and, if necessary, pulls in the target
782 * extent into the activity log, which involves further disk io because
783 * of transactional on-disk meta data updates. */
784 if (rw
== WRITE
&& local
&& !test_bit(AL_SUSPENDED
, &mdev
->flags
)) {
785 req
->rq_state
|= RQ_IN_ACT_LOG
;
786 drbd_al_begin_io(mdev
, sector
);
789 remote
= remote
&& drbd_should_do_remote(mdev
->state
);
790 send_oos
= rw
== WRITE
&& drbd_should_send_oos(mdev
->state
);
791 D_ASSERT(!(remote
&& send_oos
));
793 if (!(local
|| remote
) && !is_susp(mdev
->state
)) {
794 if (__ratelimit(&drbd_ratelimit_state
))
795 dev_err(DEV
, "IO ERROR: neither local nor remote disk\n");
797 goto fail_free_complete
;
800 /* For WRITE request, we have to make sure that we have an
801 * unused_spare_tle, in case we need to start a new epoch.
802 * I try to be smart and avoid to pre-allocate always "just in case",
803 * but there is a race between testing the bit and pointer outside the
804 * spinlock, and grabbing the spinlock.
805 * if we lost that race, we retry. */
806 if (rw
== WRITE
&& (remote
|| send_oos
) &&
807 mdev
->tconn
->unused_spare_tle
== NULL
&&
808 test_bit(CREATE_BARRIER
, &mdev
->flags
)) {
810 b
= kmalloc(sizeof(struct drbd_tl_epoch
), GFP_NOIO
);
812 dev_err(DEV
, "Failed to alloc barrier.\n");
814 goto fail_free_complete
;
818 /* GOOD, everything prepared, grab the spin_lock */
819 spin_lock_irq(&mdev
->tconn
->req_lock
);
822 err
= complete_conflicting_writes(mdev
, sector
, size
);
824 if (err
!= -ERESTARTSYS
)
825 _conn_request_state(mdev
->tconn
,
828 spin_unlock_irq(&mdev
->tconn
->req_lock
);
830 goto fail_free_complete
;
834 if (is_susp(mdev
->state
)) {
835 /* If we got suspended, use the retry mechanism of
836 generic_make_request() to restart processing of this
837 bio. In the next call to drbd_make_request
838 we sleep in inc_ap_bio() */
840 spin_unlock_irq(&mdev
->tconn
->req_lock
);
841 goto fail_free_complete
;
844 if (remote
|| send_oos
) {
845 remote
= drbd_should_do_remote(mdev
->state
);
846 send_oos
= rw
== WRITE
&& drbd_should_send_oos(mdev
->state
);
847 D_ASSERT(!(remote
&& send_oos
));
849 if (!(remote
|| send_oos
))
850 dev_warn(DEV
, "lost connection while grabbing the req_lock!\n");
851 if (!(local
|| remote
)) {
852 dev_err(DEV
, "IO ERROR: neither local nor remote disk\n");
853 spin_unlock_irq(&mdev
->tconn
->req_lock
);
855 goto fail_free_complete
;
859 if (b
&& mdev
->tconn
->unused_spare_tle
== NULL
) {
860 mdev
->tconn
->unused_spare_tle
= b
;
863 if (rw
== WRITE
&& (remote
|| send_oos
) &&
864 mdev
->tconn
->unused_spare_tle
== NULL
&&
865 test_bit(CREATE_BARRIER
, &mdev
->flags
)) {
866 /* someone closed the current epoch
867 * while we were grabbing the spinlock */
868 spin_unlock_irq(&mdev
->tconn
->req_lock
);
869 goto allocate_barrier
;
873 /* Update disk stats */
874 _drbd_start_io_acct(mdev
, req
, bio
);
876 /* _maybe_start_new_epoch(mdev);
877 * If we need to generate a write barrier packet, we have to add the
878 * new epoch (barrier) object, and queue the barrier packet for sending,
879 * and queue the req's data after it _within the same lock_, otherwise
880 * we have race conditions were the reorder domains could be mixed up.
882 * Even read requests may start a new epoch and queue the corresponding
883 * barrier packet. To get the write ordering right, we only have to
884 * make sure that, if this is a write request and it triggered a
885 * barrier packet, this request is queued within the same spinlock. */
886 if ((remote
|| send_oos
) && mdev
->tconn
->unused_spare_tle
&&
887 test_and_clear_bit(CREATE_BARRIER
, &mdev
->flags
)) {
888 _tl_add_barrier(mdev
, mdev
->tconn
->unused_spare_tle
);
889 mdev
->tconn
->unused_spare_tle
= NULL
;
891 D_ASSERT(!(remote
&& rw
== WRITE
&&
892 test_bit(CREATE_BARRIER
, &mdev
->flags
)));
896 * Actually, 'local' may be wrong here already, since we may have failed
897 * to write to the meta data, and may become wrong anytime because of
898 * local io-error for some other request, which would lead to us
899 * "detaching" the local disk.
901 * 'remote' may become wrong any time because the network could fail.
903 * This is a harmless race condition, though, since it is handled
904 * correctly at the appropriate places; so it just defers the failure
905 * of the respective operation.
908 /* mark them early for readability.
909 * this just sets some state flags. */
911 _req_mod(req
, TO_BE_SENT
);
913 _req_mod(req
, TO_BE_SUBMITTED
);
915 list_add_tail(&req
->tl_requests
, &mdev
->tconn
->newest_tle
->requests
);
917 /* NOTE remote first: to get the concurrent write detection right,
918 * we must register the request before start of local IO. */
920 /* either WRITE and C_CONNECTED,
921 * or READ, and no local disk,
922 * or READ, but not in sync.
924 _req_mod(req
, (rw
== WRITE
)
925 ? QUEUE_FOR_NET_WRITE
926 : QUEUE_FOR_NET_READ
);
928 if (send_oos
&& drbd_set_out_of_sync(mdev
, sector
, size
))
929 _req_mod(req
, QUEUE_FOR_SEND_OOS
);
932 mdev
->tconn
->net_conf
->on_congestion
!= OC_BLOCK
&& mdev
->tconn
->agreed_pro_version
>= 96) {
935 if (mdev
->tconn
->net_conf
->cong_fill
&&
936 atomic_read(&mdev
->ap_in_flight
) >= mdev
->tconn
->net_conf
->cong_fill
) {
937 dev_info(DEV
, "Congestion-fill threshold reached\n");
941 if (mdev
->act_log
->used
>= mdev
->tconn
->net_conf
->cong_extents
) {
942 dev_info(DEV
, "Congestion-extents threshold reached\n");
947 queue_barrier(mdev
); /* last barrier, after mirrored writes */
949 if (mdev
->tconn
->net_conf
->on_congestion
== OC_PULL_AHEAD
)
950 _drbd_set_state(_NS(mdev
, conn
, C_AHEAD
), 0, NULL
);
951 else /*mdev->tconn->net_conf->on_congestion == OC_DISCONNECT */
952 _drbd_set_state(_NS(mdev
, conn
, C_DISCONNECTING
), 0, NULL
);
956 spin_unlock_irq(&mdev
->tconn
->req_lock
);
957 kfree(b
); /* if someone else has beaten us to it... */
960 req
->private_bio
->bi_bdev
= mdev
->ldev
->backing_bdev
;
962 /* State may have changed since we grabbed our reference on the
963 * mdev->ldev member. Double check, and short-circuit to endio.
964 * In case the last activity log transaction failed to get on
965 * stable storage, and this is a WRITE, we may not even submit
967 if (get_ldev(mdev
)) {
968 if (drbd_insert_fault(mdev
, rw
== WRITE
? DRBD_FAULT_DT_WR
969 : rw
== READ
? DRBD_FAULT_DT_RD
971 bio_endio(req
->private_bio
, -EIO
);
973 generic_make_request(req
->private_bio
);
976 bio_endio(req
->private_bio
, -EIO
);
982 if (req
->rq_state
& RQ_IN_ACT_LOG
)
983 drbd_al_complete_io(mdev
, sector
);
986 bio_put(req
->private_bio
);
987 req
->private_bio
= NULL
;
1000 /* helper function for drbd_make_request
1001 * if we can determine just by the mdev (state) that this request will fail,
1003 * otherwise return 0
1005 static int drbd_fail_request_early(struct drbd_conf
*mdev
, int is_write
)
1007 if (mdev
->state
.role
!= R_PRIMARY
&&
1008 (!allow_oos
|| is_write
)) {
1009 if (__ratelimit(&drbd_ratelimit_state
)) {
1010 dev_err(DEV
, "Process %s[%u] tried to %s; "
1011 "since we are not in Primary state, "
1012 "we cannot allow this\n",
1013 current
->comm
, current
->pid
,
1014 is_write
? "WRITE" : "READ");
1022 int drbd_make_request(struct request_queue
*q
, struct bio
*bio
)
1024 unsigned int s_enr
, e_enr
;
1025 struct drbd_conf
*mdev
= (struct drbd_conf
*) q
->queuedata
;
1026 unsigned long start_time
;
1028 if (drbd_fail_request_early(mdev
, bio_data_dir(bio
) & WRITE
)) {
1029 bio_endio(bio
, -EPERM
);
1033 start_time
= jiffies
;
1036 * what we "blindly" assume:
1038 D_ASSERT(bio
->bi_size
> 0);
1039 D_ASSERT(IS_ALIGNED(bio
->bi_size
, 512));
1040 D_ASSERT(bio
->bi_idx
== 0);
1042 /* to make some things easier, force alignment of requests within the
1043 * granularity of our hash tables */
1044 s_enr
= bio
->bi_sector
>> HT_SHIFT
;
1045 e_enr
= (bio
->bi_sector
+(bio
->bi_size
>>9)-1) >> HT_SHIFT
;
1047 if (likely(s_enr
== e_enr
)) {
1048 inc_ap_bio(mdev
, 1);
1049 return __drbd_make_request(mdev
, bio
, start_time
);
1052 /* can this bio be split generically?
1053 * Maybe add our own split-arbitrary-bios function. */
1054 if (bio
->bi_vcnt
!= 1 || bio
->bi_idx
!= 0 || bio
->bi_size
> DRBD_MAX_BIO_SIZE
) {
1055 /* rather error out here than BUG in bio_split */
1056 dev_err(DEV
, "bio would need to, but cannot, be split: "
1057 "(vcnt=%u,idx=%u,size=%u,sector=%llu)\n",
1058 bio
->bi_vcnt
, bio
->bi_idx
, bio
->bi_size
,
1059 (unsigned long long)bio
->bi_sector
);
1060 bio_endio(bio
, -EINVAL
);
1062 /* This bio crosses some boundary, so we have to split it. */
1063 struct bio_pair
*bp
;
1064 /* works for the "do not cross hash slot boundaries" case
1065 * e.g. sector 262269, size 4096
1066 * s_enr = 262269 >> 6 = 4097
1067 * e_enr = (262269+8-1) >> 6 = 4098
1069 * sps = 64, mask = 63
1070 * first_sectors = 64 - (262269 & 63) = 3
1072 const sector_t sect
= bio
->bi_sector
;
1073 const int sps
= 1 << HT_SHIFT
; /* sectors per slot */
1074 const int mask
= sps
- 1;
1075 const sector_t first_sectors
= sps
- (sect
& mask
);
1076 bp
= bio_split(bio
, first_sectors
);
1078 /* we need to get a "reference count" (ap_bio_cnt)
1079 * to avoid races with the disconnect/reconnect/suspend code.
1080 * In case we need to split the bio here, we need to get three references
1081 * atomically, otherwise we might deadlock when trying to submit the
1083 inc_ap_bio(mdev
, 3);
1085 D_ASSERT(e_enr
== s_enr
+ 1);
1087 while (__drbd_make_request(mdev
, &bp
->bio1
, start_time
))
1088 inc_ap_bio(mdev
, 1);
1090 while (__drbd_make_request(mdev
, &bp
->bio2
, start_time
))
1091 inc_ap_bio(mdev
, 1);
1095 bio_pair_release(bp
);
1100 /* This is called by bio_add_page(). With this function we reduce
1101 * the number of BIOs that span over multiple DRBD_MAX_BIO_SIZEs
1102 * units (was AL_EXTENTs).
1104 * we do the calculation within the lower 32bit of the byte offsets,
1105 * since we don't care for actual offset, but only check whether it
1106 * would cross "activity log extent" boundaries.
1108 * As long as the BIO is empty we have to allow at least one bvec,
1109 * regardless of size and offset. so the resulting bio may still
1110 * cross extent boundaries. those are dealt with (bio_split) in
1111 * drbd_make_request.
1113 int drbd_merge_bvec(struct request_queue
*q
, struct bvec_merge_data
*bvm
, struct bio_vec
*bvec
)
1115 struct drbd_conf
*mdev
= (struct drbd_conf
*) q
->queuedata
;
1116 unsigned int bio_offset
=
1117 (unsigned int)bvm
->bi_sector
<< 9; /* 32 bit */
1118 unsigned int bio_size
= bvm
->bi_size
;
1119 int limit
, backing_limit
;
1121 limit
= DRBD_MAX_BIO_SIZE
1122 - ((bio_offset
& (DRBD_MAX_BIO_SIZE
-1)) + bio_size
);
1125 if (bio_size
== 0) {
1126 if (limit
<= bvec
->bv_len
)
1127 limit
= bvec
->bv_len
;
1128 } else if (limit
&& get_ldev(mdev
)) {
1129 struct request_queue
* const b
=
1130 mdev
->ldev
->backing_bdev
->bd_disk
->queue
;
1131 if (b
->merge_bvec_fn
) {
1132 backing_limit
= b
->merge_bvec_fn(b
, bvm
, bvec
);
1133 limit
= min(limit
, backing_limit
);
1140 void request_timer_fn(unsigned long data
)
1142 struct drbd_conf
*mdev
= (struct drbd_conf
*) data
;
1143 struct drbd_request
*req
; /* oldest request */
1144 struct list_head
*le
;
1145 unsigned long et
= 0; /* effective timeout = ko_count * timeout */
1147 if (get_net_conf(mdev
->tconn
)) {
1148 et
= mdev
->tconn
->net_conf
->timeout
*HZ
/10 * mdev
->tconn
->net_conf
->ko_count
;
1149 put_net_conf(mdev
->tconn
);
1151 if (!et
|| mdev
->state
.conn
< C_WF_REPORT_PARAMS
)
1152 return; /* Recurring timer stopped */
1154 spin_lock_irq(&mdev
->tconn
->req_lock
);
1155 le
= &mdev
->tconn
->oldest_tle
->requests
;
1156 if (list_empty(le
)) {
1157 spin_unlock_irq(&mdev
->tconn
->req_lock
);
1158 mod_timer(&mdev
->request_timer
, jiffies
+ et
);
1163 req
= list_entry(le
, struct drbd_request
, tl_requests
);
1164 if (time_is_before_eq_jiffies(req
->start_time
+ et
)) {
1165 if (req
->rq_state
& RQ_NET_PENDING
) {
1166 dev_warn(DEV
, "Remote failed to finish a request within ko-count * timeout\n");
1167 _drbd_set_state(_NS(mdev
, conn
, C_TIMEOUT
), CS_VERBOSE
, NULL
);
1169 dev_warn(DEV
, "Local backing block device frozen?\n");
1170 mod_timer(&mdev
->request_timer
, jiffies
+ et
);
1173 mod_timer(&mdev
->request_timer
, req
->start_time
+ et
);
1176 spin_unlock_irq(&mdev
->tconn
->req_lock
);