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 void _req_is_done(struct drbd_conf
*mdev
, struct drbd_request
*req
, const int rw
)
61 const unsigned long s
= req
->rq_state
;
63 /* remove it from the transfer log.
64 * well, only if it had been there in the first
65 * place... if it had not (local only or conflicting
66 * and never sent), it should still be "empty" as
67 * initialized in drbd_req_new(), so we can list_del() it
68 * here unconditionally */
69 list_del(&req
->tl_requests
);
71 /* if it was a write, we may have to set the corresponding
72 * bit(s) out-of-sync first. If it had a local part, we need to
73 * release the reference to the activity log. */
75 /* Set out-of-sync unless both OK flags are set
76 * (local only or remote failed).
77 * Other places where we set out-of-sync:
78 * READ with local io-error */
79 if (!(s
& RQ_NET_OK
) || !(s
& RQ_LOCAL_OK
))
80 drbd_set_out_of_sync(mdev
, req
->i
.sector
, req
->i
.size
);
82 if ((s
& RQ_NET_OK
) && (s
& RQ_LOCAL_OK
) && (s
& RQ_NET_SIS
))
83 drbd_set_in_sync(mdev
, req
->i
.sector
, req
->i
.size
);
85 /* one might be tempted to move the drbd_al_complete_io
86 * to the local io completion callback drbd_endio_pri.
87 * but, if this was a mirror write, we may only
88 * drbd_al_complete_io after this is RQ_NET_DONE,
89 * otherwise the extent could be dropped from the al
90 * before it has actually been written on the peer.
91 * if we crash before our peer knows about the request,
92 * but after the extent has been dropped from the al,
93 * we would forget to resync the corresponding extent.
95 if (s
& RQ_LOCAL_MASK
) {
96 if (get_ldev_if_state(mdev
, D_FAILED
)) {
97 if (s
& RQ_IN_ACT_LOG
)
98 drbd_al_complete_io(mdev
, req
->i
.sector
);
100 } else if (__ratelimit(&drbd_ratelimit_state
)) {
101 dev_warn(DEV
, "Should have called drbd_al_complete_io(, %llu), "
102 "but my Disk seems to have failed :(\n",
103 (unsigned long long) req
->i
.sector
);
111 static void queue_barrier(struct drbd_conf
*mdev
)
113 struct drbd_tl_epoch
*b
;
115 /* We are within the req_lock. Once we queued the barrier for sending,
116 * we set the CREATE_BARRIER bit. It is cleared as soon as a new
117 * barrier/epoch object is added. This is the only place this bit is
118 * set. It indicates that the barrier for this epoch is already queued,
119 * and no new epoch has been created yet. */
120 if (test_bit(CREATE_BARRIER
, &mdev
->flags
))
123 b
= mdev
->newest_tle
;
124 b
->w
.cb
= w_send_barrier
;
125 /* inc_ap_pending done here, so we won't
126 * get imbalanced on connection loss.
127 * dec_ap_pending will be done in got_BarrierAck
128 * or (on connection loss) in tl_clear. */
129 inc_ap_pending(mdev
);
130 drbd_queue_work(&mdev
->tconn
->data
.work
, &b
->w
);
131 set_bit(CREATE_BARRIER
, &mdev
->flags
);
134 static void _about_to_complete_local_write(struct drbd_conf
*mdev
,
135 struct drbd_request
*req
)
137 const unsigned long s
= req
->rq_state
;
139 /* Before we can signal completion to the upper layers,
140 * we may need to close the current epoch.
141 * We can skip this, if this request has not even been sent, because we
142 * did not have a fully established connection yet/anymore, during
143 * bitmap exchange, or while we are C_AHEAD due to congestion policy.
145 if (mdev
->state
.conn
>= C_CONNECTED
&&
146 (s
& RQ_NET_SENT
) != 0 &&
147 req
->epoch
== mdev
->newest_tle
->br_number
)
150 /* we need to do the conflict detection stuff,
151 * if the epoch_entries tree is non-empty and
152 * this request has completed on the network */
153 if ((s
& RQ_NET_DONE
) && !RB_EMPTY_ROOT(&mdev
->epoch_entries
)) {
154 const sector_t sector
= req
->i
.sector
;
155 const int size
= req
->i
.size
;
156 struct drbd_interval
*i
;
159 * there must be no conflicting requests, since
160 * they must have been failed on the spot */
162 i
= drbd_find_overlap(&mdev
->write_requests
, sector
, size
);
164 struct drbd_request
*req2
=
165 container_of(i
, struct drbd_request
, i
);
167 dev_alert(DEV
, "LOGIC BUG: completed: %p %llus +%u; "
168 "other: %p %llus +%u\n",
169 req
, (unsigned long long)sector
, size
,
170 i
, (unsigned long long)req2
->i
.sector
, req2
->i
.size
);
173 /* maybe "wake" those conflicting epoch entries
174 * that wait for this request to finish.
176 * currently, there can be only _one_ such ee
177 * (well, or some more, which would be pending
178 * P_DISCARD_ACK not yet sent by the asender...),
179 * since we block the receiver thread upon the
180 * first conflict detection, which will wait on
181 * misc_wait. maybe we want to assert that?
183 * anyways, if we found one,
184 * we just have to do a wake_up. */
185 i
= drbd_find_overlap(&mdev
->epoch_entries
, sector
, size
);
187 wake_up(&mdev
->misc_wait
);
191 void complete_master_bio(struct drbd_conf
*mdev
,
192 struct bio_and_error
*m
)
194 bio_endio(m
->bio
, m
->error
);
198 /* Helper for __req_mod().
199 * Set m->bio to the master bio, if it is fit to be completed,
200 * or leave it alone (it is initialized to NULL in __req_mod),
201 * if it has already been completed, or cannot be completed yet.
202 * If m->bio is set, the error status to be returned is placed in m->error.
204 void _req_may_be_done(struct drbd_request
*req
, struct bio_and_error
*m
)
206 const unsigned long s
= req
->rq_state
;
207 struct drbd_conf
*mdev
= req
->mdev
;
208 /* only WRITES may end up here without a master bio (on barrier ack) */
209 int rw
= req
->master_bio
? bio_data_dir(req
->master_bio
) : WRITE
;
211 /* we must not complete the master bio, while it is
212 * still being processed by _drbd_send_zc_bio (drbd_send_dblock)
213 * not yet acknowledged by the peer
214 * not yet completed by the local io subsystem
215 * these flags may get cleared in any order by
218 * the bio_endio completion callbacks.
220 if (s
& RQ_NET_QUEUED
)
222 if (s
& RQ_NET_PENDING
)
224 if (s
& RQ_LOCAL_PENDING
)
227 if (req
->master_bio
) {
228 /* this is DATA_RECEIVED (remote read)
229 * or protocol C P_WRITE_ACK
230 * or protocol B P_RECV_ACK
231 * or protocol A "HANDED_OVER_TO_NETWORK" (SendAck)
232 * or canceled or failed,
233 * or killed from the transfer log due to connection loss.
237 * figure out whether to report success or failure.
239 * report success when at least one of the operations succeeded.
240 * or, to put the other way,
241 * only report failure, when both operations failed.
243 * what to do about the failures is handled elsewhere.
244 * what we need to do here is just: complete the master_bio.
246 * local completion error, if any, has been stored as ERR_PTR
247 * in private_bio within drbd_endio_pri.
249 int ok
= (s
& RQ_LOCAL_OK
) || (s
& RQ_NET_OK
);
250 int error
= PTR_ERR(req
->private_bio
);
252 /* remove the request from the conflict detection
253 * respective block_id verification hash */
254 if (!drbd_interval_empty(&req
->i
)) {
255 struct rb_root
*root
;
258 root
= &mdev
->write_requests
;
260 root
= &mdev
->read_requests
;
261 drbd_remove_interval(root
, &req
->i
);
263 D_ASSERT((s
& (RQ_NET_MASK
& ~RQ_NET_DONE
)) == 0);
265 /* for writes we need to do some extra housekeeping */
267 _about_to_complete_local_write(mdev
, req
);
269 /* Update disk stats */
270 _drbd_end_io_acct(mdev
, req
);
272 m
->error
= ok
? 0 : (error
?: -EIO
);
273 m
->bio
= req
->master_bio
;
274 req
->master_bio
= NULL
;
277 if ((s
& RQ_NET_MASK
) == 0 || (s
& RQ_NET_DONE
)) {
278 /* this is disconnected (local only) operation,
279 * or protocol C P_WRITE_ACK,
280 * or protocol A or B P_BARRIER_ACK,
281 * or killed from the transfer log due to connection loss. */
282 _req_is_done(mdev
, req
, rw
);
284 /* else: network part and not DONE yet. that is
285 * protocol A or B, barrier ack still pending... */
288 static void _req_may_be_done_not_susp(struct drbd_request
*req
, struct bio_and_error
*m
)
290 struct drbd_conf
*mdev
= req
->mdev
;
292 if (!is_susp(mdev
->state
))
293 _req_may_be_done(req
, m
);
297 * checks whether there was an overlapping request
298 * or ee already registered.
300 * if so, return 1, in which case this request is completed on the spot,
301 * without ever being submitted or send.
303 * return 0 if it is ok to submit this request.
306 * paranoia: assume something above us is broken, and issues different write
307 * requests for the same block simultaneously...
309 * To ensure these won't be reordered differently on both nodes, resulting in
310 * diverging data sets, we discard the later one(s). Not that this is supposed
311 * to happen, but this is the rationale why we also have to check for
312 * conflicting requests with local origin, and why we have to do so regardless
313 * of whether we allowed multiple primaries.
315 * In case we only have one primary, the epoch_entries tree is empty.
317 static int _req_conflicts(struct drbd_request
*req
)
319 struct drbd_conf
*mdev
= req
->mdev
;
320 const sector_t sector
= req
->i
.sector
;
321 const int size
= req
->i
.size
;
322 struct drbd_interval
*i
;
324 D_ASSERT(drbd_interval_empty(&req
->i
));
326 if (!get_net_conf(mdev
->tconn
))
329 i
= drbd_find_overlap(&mdev
->write_requests
, sector
, size
);
331 struct drbd_request
*req2
=
332 container_of(i
, struct drbd_request
, i
);
334 dev_alert(DEV
, "%s[%u] Concurrent local write detected! "
335 "[DISCARD L] new: %llus +%u; "
336 "pending: %llus +%u\n",
337 current
->comm
, current
->pid
,
338 (unsigned long long)sector
, size
,
339 (unsigned long long)req2
->i
.sector
, req2
->i
.size
);
343 if (!RB_EMPTY_ROOT(&mdev
->epoch_entries
)) {
344 /* check for overlapping requests with remote origin */
345 i
= drbd_find_overlap(&mdev
->epoch_entries
, sector
, size
);
347 struct drbd_epoch_entry
*e
=
348 container_of(i
, struct drbd_epoch_entry
, i
);
350 dev_alert(DEV
, "%s[%u] Concurrent remote write detected!"
351 " [DISCARD L] new: %llus +%u; "
352 "pending: %llus +%u\n",
353 current
->comm
, current
->pid
,
354 (unsigned long long)sector
, size
,
355 (unsigned long long)e
->i
.sector
, e
->i
.size
);
360 /* this is like it should be, and what we expected.
361 * our users do behave after all... */
362 put_net_conf(mdev
->tconn
);
366 put_net_conf(mdev
->tconn
);
370 /* obviously this could be coded as many single functions
371 * instead of one huge switch,
372 * or by putting the code directly in the respective locations
373 * (as it has been before).
375 * but having it this way
376 * enforces that it is all in this one place, where it is easier to audit,
377 * it makes it obvious that whatever "event" "happens" to a request should
378 * happen "atomically" within the req_lock,
379 * and it enforces that we have to think in a very structured manner
380 * about the "events" that may happen to a request during its life time ...
382 int __req_mod(struct drbd_request
*req
, enum drbd_req_event what
,
383 struct bio_and_error
*m
)
385 struct drbd_conf
*mdev
= req
->mdev
;
391 dev_err(DEV
, "LOGIC BUG in %s:%u\n", __FILE__
, __LINE__
);
394 /* does not happen...
395 * initialization done in drbd_req_new
400 case TO_BE_SENT
: /* via network */
401 /* reached via drbd_make_request_common
402 * and from w_read_retry_remote */
403 D_ASSERT(!(req
->rq_state
& RQ_NET_MASK
));
404 req
->rq_state
|= RQ_NET_PENDING
;
405 inc_ap_pending(mdev
);
408 case TO_BE_SUBMITTED
: /* locally */
409 /* reached via drbd_make_request_common */
410 D_ASSERT(!(req
->rq_state
& RQ_LOCAL_MASK
));
411 req
->rq_state
|= RQ_LOCAL_PENDING
;
415 if (bio_data_dir(req
->master_bio
) == WRITE
)
416 mdev
->writ_cnt
+= req
->i
.size
>> 9;
418 mdev
->read_cnt
+= req
->i
.size
>> 9;
420 req
->rq_state
|= (RQ_LOCAL_COMPLETED
|RQ_LOCAL_OK
);
421 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
423 _req_may_be_done_not_susp(req
, m
);
427 case WRITE_COMPLETED_WITH_ERROR
:
428 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
429 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
431 __drbd_chk_io_error(mdev
, false);
432 _req_may_be_done_not_susp(req
, m
);
436 case READ_AHEAD_COMPLETED_WITH_ERROR
:
437 /* it is legal to fail READA */
438 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
439 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
440 _req_may_be_done_not_susp(req
, m
);
444 case READ_COMPLETED_WITH_ERROR
:
445 drbd_set_out_of_sync(mdev
, req
->i
.sector
, req
->i
.size
);
447 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
448 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
450 D_ASSERT(!(req
->rq_state
& RQ_NET_MASK
));
452 __drbd_chk_io_error(mdev
, false);
455 /* no point in retrying if there is no good remote data,
456 * or we have no connection. */
457 if (mdev
->state
.pdsk
!= D_UP_TO_DATE
) {
458 _req_may_be_done_not_susp(req
, m
);
462 /* _req_mod(req,TO_BE_SENT); oops, recursion... */
463 req
->rq_state
|= RQ_NET_PENDING
;
464 inc_ap_pending(mdev
);
465 /* fall through: _req_mod(req,QUEUE_FOR_NET_READ); */
467 case QUEUE_FOR_NET_READ
:
468 /* READ or READA, and
470 * or target area marked as invalid,
471 * or just got an io-error. */
472 /* from drbd_make_request_common
473 * or from bio_endio during read io-error recovery */
475 /* so we can verify the handle in the answer packet
476 * corresponding hlist_del is in _req_may_be_done() */
477 drbd_insert_interval(&mdev
->read_requests
, &req
->i
);
479 set_bit(UNPLUG_REMOTE
, &mdev
->flags
);
481 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
482 req
->rq_state
|= RQ_NET_QUEUED
;
483 req
->w
.cb
= (req
->rq_state
& RQ_LOCAL_MASK
)
484 ? w_read_retry_remote
486 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
489 case QUEUE_FOR_NET_WRITE
:
490 /* assert something? */
491 /* from drbd_make_request_common only */
493 /* corresponding hlist_del is in _req_may_be_done() */
494 drbd_insert_interval(&mdev
->write_requests
, &req
->i
);
497 * In case the req ended up on the transfer log before being
498 * queued on the worker, it could lead to this request being
499 * missed during cleanup after connection loss.
500 * So we have to do both operations here,
501 * within the same lock that protects the transfer log.
503 * _req_add_to_epoch(req); this has to be after the
504 * _maybe_start_new_epoch(req); which happened in
505 * drbd_make_request_common, because we now may set the bit
506 * again ourselves to close the current epoch.
508 * Add req to the (now) current epoch (barrier). */
510 /* otherwise we may lose an unplug, which may cause some remote
511 * io-scheduler timeout to expire, increasing maximum latency,
512 * hurting performance. */
513 set_bit(UNPLUG_REMOTE
, &mdev
->flags
);
515 /* see drbd_make_request_common,
516 * just after it grabs the req_lock */
517 D_ASSERT(test_bit(CREATE_BARRIER
, &mdev
->flags
) == 0);
519 req
->epoch
= mdev
->newest_tle
->br_number
;
521 /* increment size of current epoch */
522 mdev
->newest_tle
->n_writes
++;
524 /* queue work item to send data */
525 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
526 req
->rq_state
|= RQ_NET_QUEUED
;
527 req
->w
.cb
= w_send_dblock
;
528 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
530 /* close the epoch, in case it outgrew the limit */
531 if (mdev
->newest_tle
->n_writes
>= mdev
->tconn
->net_conf
->max_epoch_size
)
536 case QUEUE_FOR_SEND_OOS
:
537 req
->rq_state
|= RQ_NET_QUEUED
;
538 req
->w
.cb
= w_send_oos
;
539 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
542 case OOS_HANDED_TO_NETWORK
:
543 /* actually the same */
545 /* treat it the same */
547 /* real cleanup will be done from tl_clear. just update flags
548 * so it is no longer marked as on the worker queue */
549 req
->rq_state
&= ~RQ_NET_QUEUED
;
550 /* if we did it right, tl_clear should be scheduled only after
551 * this, so this should not be necessary! */
552 _req_may_be_done_not_susp(req
, m
);
555 case HANDED_OVER_TO_NETWORK
:
556 /* assert something? */
557 if (bio_data_dir(req
->master_bio
) == WRITE
)
558 atomic_add(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
560 if (bio_data_dir(req
->master_bio
) == WRITE
&&
561 mdev
->tconn
->net_conf
->wire_protocol
== DRBD_PROT_A
) {
562 /* this is what is dangerous about protocol A:
563 * pretend it was successfully written on the peer. */
564 if (req
->rq_state
& RQ_NET_PENDING
) {
565 dec_ap_pending(mdev
);
566 req
->rq_state
&= ~RQ_NET_PENDING
;
567 req
->rq_state
|= RQ_NET_OK
;
568 } /* else: neg-ack was faster... */
569 /* it is still not yet RQ_NET_DONE until the
570 * corresponding epoch barrier got acked as well,
571 * so we know what to dirty on connection loss */
573 req
->rq_state
&= ~RQ_NET_QUEUED
;
574 req
->rq_state
|= RQ_NET_SENT
;
575 /* because _drbd_send_zc_bio could sleep, and may want to
576 * dereference the bio even after the "WRITE_ACKED_BY_PEER" and
577 * "COMPLETED_OK" events came in, once we return from
578 * _drbd_send_zc_bio (drbd_send_dblock), we have to check
579 * whether it is done already, and end it. */
580 _req_may_be_done_not_susp(req
, m
);
583 case READ_RETRY_REMOTE_CANCELED
:
584 req
->rq_state
&= ~RQ_NET_QUEUED
;
585 /* fall through, in case we raced with drbd_disconnect */
586 case CONNECTION_LOST_WHILE_PENDING
:
587 /* transfer log cleanup after connection loss */
588 /* assert something? */
589 if (req
->rq_state
& RQ_NET_PENDING
)
590 dec_ap_pending(mdev
);
591 req
->rq_state
&= ~(RQ_NET_OK
|RQ_NET_PENDING
);
592 req
->rq_state
|= RQ_NET_DONE
;
593 if (req
->rq_state
& RQ_NET_SENT
&& req
->rq_state
& RQ_WRITE
)
594 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
596 /* if it is still queued, we may not complete it here.
597 * it will be canceled soon. */
598 if (!(req
->rq_state
& RQ_NET_QUEUED
))
599 _req_may_be_done(req
, m
); /* Allowed while state.susp */
602 case WRITE_ACKED_BY_PEER_AND_SIS
:
603 req
->rq_state
|= RQ_NET_SIS
;
604 case CONFLICT_DISCARDED_BY_PEER
:
605 /* for discarded conflicting writes of multiple primaries,
606 * there is no need to keep anything in the tl, potential
607 * node crashes are covered by the activity log. */
608 if (what
== CONFLICT_DISCARDED_BY_PEER
)
609 dev_alert(DEV
, "Got DiscardAck packet %llus +%u!"
610 " DRBD is not a random data generator!\n",
611 (unsigned long long)req
->i
.sector
, req
->i
.size
);
612 req
->rq_state
|= RQ_NET_DONE
;
614 case WRITE_ACKED_BY_PEER
:
615 /* protocol C; successfully written on peer.
616 * Nothing to do here.
617 * We want to keep the tl in place for all protocols, to cater
618 * for volatile write-back caches on lower level devices.
620 * A barrier request is expected to have forced all prior
621 * requests onto stable storage, so completion of a barrier
622 * request could set NET_DONE right here, and not wait for the
623 * P_BARRIER_ACK, but that is an unnecessary optimization. */
625 /* this makes it effectively the same as for: */
626 case RECV_ACKED_BY_PEER
:
627 /* protocol B; pretends to be successfully written on peer.
628 * see also notes above in HANDED_OVER_TO_NETWORK about
630 req
->rq_state
|= RQ_NET_OK
;
631 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
632 dec_ap_pending(mdev
);
633 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
634 req
->rq_state
&= ~RQ_NET_PENDING
;
635 _req_may_be_done_not_susp(req
, m
);
639 /* assert something? */
640 if (req
->rq_state
& RQ_NET_PENDING
) {
641 dec_ap_pending(mdev
);
642 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
644 req
->rq_state
&= ~(RQ_NET_OK
|RQ_NET_PENDING
);
646 req
->rq_state
|= RQ_NET_DONE
;
647 _req_may_be_done_not_susp(req
, m
);
648 /* else: done by HANDED_OVER_TO_NETWORK */
651 case FAIL_FROZEN_DISK_IO
:
652 if (!(req
->rq_state
& RQ_LOCAL_COMPLETED
))
655 _req_may_be_done(req
, m
); /* Allowed while state.susp */
658 case RESTART_FROZEN_DISK_IO
:
659 if (!(req
->rq_state
& RQ_LOCAL_COMPLETED
))
662 req
->rq_state
&= ~RQ_LOCAL_COMPLETED
;
665 if (bio_data_dir(req
->master_bio
) == WRITE
)
669 req
->w
.cb
= w_restart_disk_io
;
670 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
674 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK
675 before the connection loss (B&C only); only P_BARRIER_ACK was missing.
676 Trowing them out of the TL here by pretending we got a BARRIER_ACK
677 We ensure that the peer was not rebooted */
678 if (!(req
->rq_state
& RQ_NET_OK
)) {
680 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
681 rv
= req
->rq_state
& RQ_WRITE
? MR_WRITE
: MR_READ
;
685 /* else, fall through to BARRIER_ACKED */
688 if (!(req
->rq_state
& RQ_WRITE
))
691 if (req
->rq_state
& RQ_NET_PENDING
) {
692 /* barrier came in before all requests have been acked.
693 * this is bad, because if the connection is lost now,
694 * we won't be able to clean them up... */
695 dev_err(DEV
, "FIXME (BARRIER_ACKED but pending)\n");
696 list_move(&req
->tl_requests
, &mdev
->out_of_sequence_requests
);
698 if ((req
->rq_state
& RQ_NET_MASK
) != 0) {
699 req
->rq_state
|= RQ_NET_DONE
;
700 if (mdev
->tconn
->net_conf
->wire_protocol
== DRBD_PROT_A
)
701 atomic_sub(req
->i
.size
>>9, &mdev
->ap_in_flight
);
703 _req_may_be_done(req
, m
); /* Allowed while state.susp */
707 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
708 dec_ap_pending(mdev
);
709 req
->rq_state
&= ~RQ_NET_PENDING
;
710 req
->rq_state
|= (RQ_NET_OK
|RQ_NET_DONE
);
711 _req_may_be_done_not_susp(req
, m
);
718 /* we may do a local read if:
719 * - we are consistent (of course),
720 * - or we are generally inconsistent,
721 * BUT we are still/already IN SYNC for this area.
722 * since size may be bigger than BM_BLOCK_SIZE,
723 * we may need to check several bits.
725 static int drbd_may_do_local_read(struct drbd_conf
*mdev
, sector_t sector
, int size
)
727 unsigned long sbnr
, ebnr
;
728 sector_t esector
, nr_sectors
;
730 if (mdev
->state
.disk
== D_UP_TO_DATE
)
732 if (mdev
->state
.disk
>= D_OUTDATED
)
734 if (mdev
->state
.disk
< D_INCONSISTENT
)
736 /* state.disk == D_INCONSISTENT We will have a look at the BitMap */
737 nr_sectors
= drbd_get_capacity(mdev
->this_bdev
);
738 esector
= sector
+ (size
>> 9) - 1;
740 D_ASSERT(sector
< nr_sectors
);
741 D_ASSERT(esector
< nr_sectors
);
743 sbnr
= BM_SECT_TO_BIT(sector
);
744 ebnr
= BM_SECT_TO_BIT(esector
);
746 return 0 == drbd_bm_count_bits(mdev
, sbnr
, ebnr
);
749 static int drbd_make_request_common(struct drbd_conf
*mdev
, struct bio
*bio
, unsigned long start_time
)
751 const int rw
= bio_rw(bio
);
752 const int size
= bio
->bi_size
;
753 const sector_t sector
= bio
->bi_sector
;
754 struct drbd_tl_epoch
*b
= NULL
;
755 struct drbd_request
*req
;
756 int local
, remote
, send_oos
= 0;
760 /* allocate outside of all locks; */
761 req
= drbd_req_new(mdev
, bio
);
764 /* only pass the error to the upper layers.
765 * if user cannot handle io errors, that's not our business. */
766 dev_err(DEV
, "could not kmalloc() req\n");
767 bio_endio(bio
, -ENOMEM
);
770 req
->start_time
= start_time
;
772 local
= get_ldev(mdev
);
774 bio_put(req
->private_bio
); /* or we get a bio leak */
775 req
->private_bio
= NULL
;
782 if (!drbd_may_do_local_read(mdev
, sector
, size
)) {
783 /* we could kick the syncer to
784 * sync this extent asap, wait for
785 * it, then continue locally.
786 * Or just issue the request remotely.
789 bio_put(req
->private_bio
);
790 req
->private_bio
= NULL
;
794 remote
= !local
&& mdev
->state
.pdsk
>= D_UP_TO_DATE
;
797 /* If we have a disk, but a READA request is mapped to remote,
798 * we are R_PRIMARY, D_INCONSISTENT, SyncTarget.
799 * Just fail that READA request right here.
801 * THINK: maybe fail all READA when not local?
802 * or make this configurable...
803 * if network is slow, READA won't do any good.
805 if (rw
== READA
&& mdev
->state
.disk
>= D_INCONSISTENT
&& !local
) {
807 goto fail_and_free_req
;
810 /* For WRITES going to the local disk, grab a reference on the target
811 * extent. This waits for any resync activity in the corresponding
812 * resync extent to finish, and, if necessary, pulls in the target
813 * extent into the activity log, which involves further disk io because
814 * of transactional on-disk meta data updates. */
815 if (rw
== WRITE
&& local
&& !test_bit(AL_SUSPENDED
, &mdev
->flags
)) {
816 req
->rq_state
|= RQ_IN_ACT_LOG
;
817 drbd_al_begin_io(mdev
, sector
);
820 remote
= remote
&& drbd_should_do_remote(mdev
->state
);
821 send_oos
= rw
== WRITE
&& drbd_should_send_oos(mdev
->state
);
822 D_ASSERT(!(remote
&& send_oos
));
824 if (!(local
|| remote
) && !is_susp(mdev
->state
)) {
825 if (__ratelimit(&drbd_ratelimit_state
))
826 dev_err(DEV
, "IO ERROR: neither local nor remote disk\n");
827 goto fail_free_complete
;
830 /* For WRITE request, we have to make sure that we have an
831 * unused_spare_tle, in case we need to start a new epoch.
832 * I try to be smart and avoid to pre-allocate always "just in case",
833 * but there is a race between testing the bit and pointer outside the
834 * spinlock, and grabbing the spinlock.
835 * if we lost that race, we retry. */
836 if (rw
== WRITE
&& (remote
|| send_oos
) &&
837 mdev
->unused_spare_tle
== NULL
&&
838 test_bit(CREATE_BARRIER
, &mdev
->flags
)) {
840 b
= kmalloc(sizeof(struct drbd_tl_epoch
), GFP_NOIO
);
842 dev_err(DEV
, "Failed to alloc barrier.\n");
844 goto fail_free_complete
;
848 /* GOOD, everything prepared, grab the spin_lock */
849 spin_lock_irq(&mdev
->req_lock
);
851 if (is_susp(mdev
->state
)) {
852 /* If we got suspended, use the retry mechanism of
853 generic_make_request() to restart processing of this
854 bio. In the next call to drbd_make_request
855 we sleep in inc_ap_bio() */
857 spin_unlock_irq(&mdev
->req_lock
);
858 goto fail_free_complete
;
861 if (remote
|| send_oos
) {
862 remote
= drbd_should_do_remote(mdev
->state
);
863 send_oos
= rw
== WRITE
&& drbd_should_send_oos(mdev
->state
);
864 D_ASSERT(!(remote
&& send_oos
));
866 if (!(remote
|| send_oos
))
867 dev_warn(DEV
, "lost connection while grabbing the req_lock!\n");
868 if (!(local
|| remote
)) {
869 dev_err(DEV
, "IO ERROR: neither local nor remote disk\n");
870 spin_unlock_irq(&mdev
->req_lock
);
871 goto fail_free_complete
;
875 if (b
&& mdev
->unused_spare_tle
== NULL
) {
876 mdev
->unused_spare_tle
= b
;
879 if (rw
== WRITE
&& (remote
|| send_oos
) &&
880 mdev
->unused_spare_tle
== NULL
&&
881 test_bit(CREATE_BARRIER
, &mdev
->flags
)) {
882 /* someone closed the current epoch
883 * while we were grabbing the spinlock */
884 spin_unlock_irq(&mdev
->req_lock
);
885 goto allocate_barrier
;
889 /* Update disk stats */
890 _drbd_start_io_acct(mdev
, req
, bio
);
892 /* _maybe_start_new_epoch(mdev);
893 * If we need to generate a write barrier packet, we have to add the
894 * new epoch (barrier) object, and queue the barrier packet for sending,
895 * and queue the req's data after it _within the same lock_, otherwise
896 * we have race conditions were the reorder domains could be mixed up.
898 * Even read requests may start a new epoch and queue the corresponding
899 * barrier packet. To get the write ordering right, we only have to
900 * make sure that, if this is a write request and it triggered a
901 * barrier packet, this request is queued within the same spinlock. */
902 if ((remote
|| send_oos
) && mdev
->unused_spare_tle
&&
903 test_and_clear_bit(CREATE_BARRIER
, &mdev
->flags
)) {
904 _tl_add_barrier(mdev
, mdev
->unused_spare_tle
);
905 mdev
->unused_spare_tle
= NULL
;
907 D_ASSERT(!(remote
&& rw
== WRITE
&&
908 test_bit(CREATE_BARRIER
, &mdev
->flags
)));
912 * Actually, 'local' may be wrong here already, since we may have failed
913 * to write to the meta data, and may become wrong anytime because of
914 * local io-error for some other request, which would lead to us
915 * "detaching" the local disk.
917 * 'remote' may become wrong any time because the network could fail.
919 * This is a harmless race condition, though, since it is handled
920 * correctly at the appropriate places; so it just defers the failure
921 * of the respective operation.
924 /* mark them early for readability.
925 * this just sets some state flags. */
927 _req_mod(req
, TO_BE_SENT
);
929 _req_mod(req
, TO_BE_SUBMITTED
);
931 /* check this request on the collision detection hash tables.
932 * if we have a conflict, just complete it here.
933 * THINK do we want to check reads, too? (I don't think so...) */
934 if (rw
== WRITE
&& _req_conflicts(req
))
935 goto fail_conflicting
;
937 list_add_tail(&req
->tl_requests
, &mdev
->newest_tle
->requests
);
939 /* NOTE remote first: to get the concurrent write detection right,
940 * we must register the request before start of local IO. */
942 /* either WRITE and C_CONNECTED,
943 * or READ, and no local disk,
944 * or READ, but not in sync.
946 _req_mod(req
, (rw
== WRITE
)
947 ? QUEUE_FOR_NET_WRITE
948 : QUEUE_FOR_NET_READ
);
950 if (send_oos
&& drbd_set_out_of_sync(mdev
, sector
, size
))
951 _req_mod(req
, QUEUE_FOR_SEND_OOS
);
954 mdev
->tconn
->net_conf
->on_congestion
!= OC_BLOCK
&& mdev
->tconn
->agreed_pro_version
>= 96) {
957 if (mdev
->tconn
->net_conf
->cong_fill
&&
958 atomic_read(&mdev
->ap_in_flight
) >= mdev
->tconn
->net_conf
->cong_fill
) {
959 dev_info(DEV
, "Congestion-fill threshold reached\n");
963 if (mdev
->act_log
->used
>= mdev
->tconn
->net_conf
->cong_extents
) {
964 dev_info(DEV
, "Congestion-extents threshold reached\n");
969 queue_barrier(mdev
); /* last barrier, after mirrored writes */
971 if (mdev
->tconn
->net_conf
->on_congestion
== OC_PULL_AHEAD
)
972 _drbd_set_state(_NS(mdev
, conn
, C_AHEAD
), 0, NULL
);
973 else /*mdev->tconn->net_conf->on_congestion == OC_DISCONNECT */
974 _drbd_set_state(_NS(mdev
, conn
, C_DISCONNECTING
), 0, NULL
);
978 spin_unlock_irq(&mdev
->req_lock
);
979 kfree(b
); /* if someone else has beaten us to it... */
982 req
->private_bio
->bi_bdev
= mdev
->ldev
->backing_bdev
;
984 /* State may have changed since we grabbed our reference on the
985 * mdev->ldev member. Double check, and short-circuit to endio.
986 * In case the last activity log transaction failed to get on
987 * stable storage, and this is a WRITE, we may not even submit
989 if (get_ldev(mdev
)) {
990 if (drbd_insert_fault(mdev
, rw
== WRITE
? DRBD_FAULT_DT_WR
991 : rw
== READ
? DRBD_FAULT_DT_RD
993 bio_endio(req
->private_bio
, -EIO
);
995 generic_make_request(req
->private_bio
);
998 bio_endio(req
->private_bio
, -EIO
);
1004 /* this is a conflicting request.
1005 * even though it may have been only _partially_
1006 * overlapping with one of the currently pending requests,
1007 * without even submitting or sending it, we will
1008 * pretend that it was successfully served right now.
1010 _drbd_end_io_acct(mdev
, req
);
1011 spin_unlock_irq(&mdev
->req_lock
);
1013 dec_ap_pending(mdev
);
1014 /* THINK: do we want to fail it (-EIO), or pretend success?
1015 * this pretends success. */
1019 if (req
->rq_state
& RQ_IN_ACT_LOG
)
1020 drbd_al_complete_io(mdev
, sector
);
1023 bio_put(req
->private_bio
);
1024 req
->private_bio
= NULL
;
1028 bio_endio(bio
, err
);
1037 /* helper function for drbd_make_request
1038 * if we can determine just by the mdev (state) that this request will fail,
1040 * otherwise return 0
1042 static int drbd_fail_request_early(struct drbd_conf
*mdev
, int is_write
)
1044 if (mdev
->state
.role
!= R_PRIMARY
&&
1045 (!allow_oos
|| is_write
)) {
1046 if (__ratelimit(&drbd_ratelimit_state
)) {
1047 dev_err(DEV
, "Process %s[%u] tried to %s; "
1048 "since we are not in Primary state, "
1049 "we cannot allow this\n",
1050 current
->comm
, current
->pid
,
1051 is_write
? "WRITE" : "READ");
1059 int drbd_make_request(struct request_queue
*q
, struct bio
*bio
)
1061 unsigned int s_enr
, e_enr
;
1062 struct drbd_conf
*mdev
= (struct drbd_conf
*) q
->queuedata
;
1063 unsigned long start_time
;
1065 if (drbd_fail_request_early(mdev
, bio_data_dir(bio
) & WRITE
)) {
1066 bio_endio(bio
, -EPERM
);
1070 start_time
= jiffies
;
1073 * what we "blindly" assume:
1075 D_ASSERT(bio
->bi_size
> 0);
1076 D_ASSERT((bio
->bi_size
& 0x1ff) == 0);
1077 D_ASSERT(bio
->bi_idx
== 0);
1079 /* to make some things easier, force alignment of requests within the
1080 * granularity of our hash tables */
1081 s_enr
= bio
->bi_sector
>> HT_SHIFT
;
1082 e_enr
= (bio
->bi_sector
+(bio
->bi_size
>>9)-1) >> HT_SHIFT
;
1084 if (likely(s_enr
== e_enr
)) {
1085 inc_ap_bio(mdev
, 1);
1086 return drbd_make_request_common(mdev
, bio
, start_time
);
1089 /* can this bio be split generically?
1090 * Maybe add our own split-arbitrary-bios function. */
1091 if (bio
->bi_vcnt
!= 1 || bio
->bi_idx
!= 0 || bio
->bi_size
> DRBD_MAX_BIO_SIZE
) {
1092 /* rather error out here than BUG in bio_split */
1093 dev_err(DEV
, "bio would need to, but cannot, be split: "
1094 "(vcnt=%u,idx=%u,size=%u,sector=%llu)\n",
1095 bio
->bi_vcnt
, bio
->bi_idx
, bio
->bi_size
,
1096 (unsigned long long)bio
->bi_sector
);
1097 bio_endio(bio
, -EINVAL
);
1099 /* This bio crosses some boundary, so we have to split it. */
1100 struct bio_pair
*bp
;
1101 /* works for the "do not cross hash slot boundaries" case
1102 * e.g. sector 262269, size 4096
1103 * s_enr = 262269 >> 6 = 4097
1104 * e_enr = (262269+8-1) >> 6 = 4098
1106 * sps = 64, mask = 63
1107 * first_sectors = 64 - (262269 & 63) = 3
1109 const sector_t sect
= bio
->bi_sector
;
1110 const int sps
= 1 << HT_SHIFT
; /* sectors per slot */
1111 const int mask
= sps
- 1;
1112 const sector_t first_sectors
= sps
- (sect
& mask
);
1113 bp
= bio_split(bio
, first_sectors
);
1115 /* we need to get a "reference count" (ap_bio_cnt)
1116 * to avoid races with the disconnect/reconnect/suspend code.
1117 * In case we need to split the bio here, we need to get three references
1118 * atomically, otherwise we might deadlock when trying to submit the
1120 inc_ap_bio(mdev
, 3);
1122 D_ASSERT(e_enr
== s_enr
+ 1);
1124 while (drbd_make_request_common(mdev
, &bp
->bio1
, start_time
))
1125 inc_ap_bio(mdev
, 1);
1127 while (drbd_make_request_common(mdev
, &bp
->bio2
, start_time
))
1128 inc_ap_bio(mdev
, 1);
1132 bio_pair_release(bp
);
1137 /* This is called by bio_add_page(). With this function we reduce
1138 * the number of BIOs that span over multiple DRBD_MAX_BIO_SIZEs
1139 * units (was AL_EXTENTs).
1141 * we do the calculation within the lower 32bit of the byte offsets,
1142 * since we don't care for actual offset, but only check whether it
1143 * would cross "activity log extent" boundaries.
1145 * As long as the BIO is empty we have to allow at least one bvec,
1146 * regardless of size and offset. so the resulting bio may still
1147 * cross extent boundaries. those are dealt with (bio_split) in
1148 * drbd_make_request.
1150 int drbd_merge_bvec(struct request_queue
*q
, struct bvec_merge_data
*bvm
, struct bio_vec
*bvec
)
1152 struct drbd_conf
*mdev
= (struct drbd_conf
*) q
->queuedata
;
1153 unsigned int bio_offset
=
1154 (unsigned int)bvm
->bi_sector
<< 9; /* 32 bit */
1155 unsigned int bio_size
= bvm
->bi_size
;
1156 int limit
, backing_limit
;
1158 limit
= DRBD_MAX_BIO_SIZE
1159 - ((bio_offset
& (DRBD_MAX_BIO_SIZE
-1)) + bio_size
);
1162 if (bio_size
== 0) {
1163 if (limit
<= bvec
->bv_len
)
1164 limit
= bvec
->bv_len
;
1165 } else if (limit
&& get_ldev(mdev
)) {
1166 struct request_queue
* const b
=
1167 mdev
->ldev
->backing_bdev
->bd_disk
->queue
;
1168 if (b
->merge_bvec_fn
) {
1169 backing_limit
= b
->merge_bvec_fn(b
, bvm
, bvec
);
1170 limit
= min(limit
, backing_limit
);
1177 void request_timer_fn(unsigned long data
)
1179 struct drbd_conf
*mdev
= (struct drbd_conf
*) data
;
1180 struct drbd_request
*req
; /* oldest request */
1181 struct list_head
*le
;
1182 unsigned long et
= 0; /* effective timeout = ko_count * timeout */
1184 if (get_net_conf(mdev
->tconn
)) {
1185 et
= mdev
->tconn
->net_conf
->timeout
*HZ
/10 * mdev
->tconn
->net_conf
->ko_count
;
1186 put_net_conf(mdev
->tconn
);
1188 if (!et
|| mdev
->state
.conn
< C_WF_REPORT_PARAMS
)
1189 return; /* Recurring timer stopped */
1191 spin_lock_irq(&mdev
->req_lock
);
1192 le
= &mdev
->oldest_tle
->requests
;
1193 if (list_empty(le
)) {
1194 spin_unlock_irq(&mdev
->req_lock
);
1195 mod_timer(&mdev
->request_timer
, jiffies
+ et
);
1200 req
= list_entry(le
, struct drbd_request
, tl_requests
);
1201 if (time_is_before_eq_jiffies(req
->start_time
+ et
)) {
1202 if (req
->rq_state
& RQ_NET_PENDING
) {
1203 dev_warn(DEV
, "Remote failed to finish a request within ko-count * timeout\n");
1204 _drbd_set_state(_NS(mdev
, conn
, C_TIMEOUT
), CS_VERBOSE
, NULL
);
1206 dev_warn(DEV
, "Local backing block device frozen?\n");
1207 mod_timer(&mdev
->request_timer
, jiffies
+ et
);
1210 mod_timer(&mdev
->request_timer
, req
->start_time
+ et
);
1213 spin_unlock_irq(&mdev
->req_lock
);