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_conf
*mdev
, sector_t sector
, int size
);
36 /* Update disk stats at start of I/O request */
37 static void _drbd_start_io_acct(struct drbd_conf
*mdev
, struct drbd_request
*req
, struct bio
*bio
)
39 const int rw
= bio_data_dir(bio
);
41 cpu
= part_stat_lock();
42 part_stat_inc(cpu
, &mdev
->vdisk
->part0
, ios
[rw
]);
43 part_stat_add(cpu
, &mdev
->vdisk
->part0
, sectors
[rw
], bio_sectors(bio
));
44 (void) cpu
; /* The macro invocations above want the cpu argument, I do not like
45 the compiler warning about cpu only assigned but never used... */
46 part_inc_in_flight(&mdev
->vdisk
->part0
, rw
);
50 /* Update disk stats when completing request upwards */
51 static void _drbd_end_io_acct(struct drbd_conf
*mdev
, struct drbd_request
*req
)
53 int rw
= bio_data_dir(req
->master_bio
);
54 unsigned long duration
= jiffies
- req
->start_time
;
56 cpu
= part_stat_lock();
57 part_stat_add(cpu
, &mdev
->vdisk
->part0
, ticks
[rw
], duration
);
58 part_round_stats(cpu
, &mdev
->vdisk
->part0
);
59 part_dec_in_flight(&mdev
->vdisk
->part0
, rw
);
63 static struct drbd_request
*drbd_req_new(struct drbd_conf
*mdev
,
66 struct drbd_request
*req
;
68 req
= mempool_alloc(drbd_request_mempool
, GFP_NOIO
);
72 drbd_req_make_private_bio(req
, bio_src
);
73 req
->rq_state
= bio_data_dir(bio_src
) == WRITE
? RQ_WRITE
: 0;
75 req
->master_bio
= bio_src
;
78 drbd_clear_interval(&req
->i
);
79 req
->i
.sector
= bio_src
->bi_sector
;
80 req
->i
.size
= bio_src
->bi_size
;
82 req
->i
.waiting
= false;
84 INIT_LIST_HEAD(&req
->tl_requests
);
85 INIT_LIST_HEAD(&req
->w
.list
);
90 static void drbd_req_free(struct drbd_request
*req
)
92 mempool_free(req
, drbd_request_mempool
);
95 /* rw is bio_data_dir(), only READ or WRITE */
96 static void _req_is_done(struct drbd_conf
*mdev
, struct drbd_request
*req
, const int rw
)
98 const unsigned long s
= req
->rq_state
;
100 /* remove it from the transfer log.
101 * well, only if it had been there in the first
102 * place... if it had not (local only or conflicting
103 * and never sent), it should still be "empty" as
104 * initialized in drbd_req_new(), so we can list_del() it
105 * here unconditionally */
106 list_del(&req
->tl_requests
);
108 /* if it was a write, we may have to set the corresponding
109 * bit(s) out-of-sync first. If it had a local part, we need to
110 * release the reference to the activity log. */
112 /* Set out-of-sync unless both OK flags are set
113 * (local only or remote failed).
114 * Other places where we set out-of-sync:
115 * READ with local io-error */
116 if (!(s
& RQ_NET_OK
) || !(s
& RQ_LOCAL_OK
))
117 drbd_set_out_of_sync(mdev
, req
->i
.sector
, req
->i
.size
);
119 if ((s
& RQ_NET_OK
) && (s
& RQ_LOCAL_OK
) && (s
& RQ_NET_SIS
))
120 drbd_set_in_sync(mdev
, req
->i
.sector
, req
->i
.size
);
122 /* one might be tempted to move the drbd_al_complete_io
123 * to the local io completion callback drbd_request_endio.
124 * but, if this was a mirror write, we may only
125 * drbd_al_complete_io after this is RQ_NET_DONE,
126 * otherwise the extent could be dropped from the al
127 * before it has actually been written on the peer.
128 * if we crash before our peer knows about the request,
129 * but after the extent has been dropped from the al,
130 * we would forget to resync the corresponding extent.
132 if (s
& RQ_LOCAL_MASK
) {
133 if (get_ldev_if_state(mdev
, D_FAILED
)) {
134 if (s
& RQ_IN_ACT_LOG
)
135 drbd_al_complete_io(mdev
, &req
->i
);
137 } else if (__ratelimit(&drbd_ratelimit_state
)) {
138 dev_warn(DEV
, "Should have called drbd_al_complete_io(, %llu, %u), "
139 "but my Disk seems to have failed :(\n",
140 (unsigned long long) req
->i
.sector
, req
->i
.size
);
148 static void queue_barrier(struct drbd_conf
*mdev
)
150 struct drbd_tl_epoch
*b
;
151 struct drbd_tconn
*tconn
= mdev
->tconn
;
153 /* We are within the req_lock. Once we queued the barrier for sending,
154 * we set the CREATE_BARRIER bit. It is cleared as soon as a new
155 * barrier/epoch object is added. This is the only place this bit is
156 * set. It indicates that the barrier for this epoch is already queued,
157 * and no new epoch has been created yet. */
158 if (test_bit(CREATE_BARRIER
, &tconn
->flags
))
161 b
= tconn
->newest_tle
;
162 b
->w
.cb
= w_send_barrier
;
164 /* inc_ap_pending done here, so we won't
165 * get imbalanced on connection loss.
166 * dec_ap_pending will be done in got_BarrierAck
167 * or (on connection loss) in tl_clear. */
168 inc_ap_pending(mdev
);
169 drbd_queue_work(&tconn
->data
.work
, &b
->w
);
170 set_bit(CREATE_BARRIER
, &tconn
->flags
);
173 static void _about_to_complete_local_write(struct drbd_conf
*mdev
,
174 struct drbd_request
*req
)
176 const unsigned long s
= req
->rq_state
;
178 /* Before we can signal completion to the upper layers,
179 * we may need to close the current epoch.
180 * We can skip this, if this request has not even been sent, because we
181 * did not have a fully established connection yet/anymore, during
182 * bitmap exchange, or while we are C_AHEAD due to congestion policy.
184 if (mdev
->state
.conn
>= C_CONNECTED
&&
185 (s
& RQ_NET_SENT
) != 0 &&
186 req
->epoch
== mdev
->tconn
->newest_tle
->br_number
)
190 void complete_master_bio(struct drbd_conf
*mdev
,
191 struct bio_and_error
*m
)
193 bio_endio(m
->bio
, m
->error
);
198 static void drbd_remove_request_interval(struct rb_root
*root
,
199 struct drbd_request
*req
)
201 struct drbd_conf
*mdev
= req
->w
.mdev
;
202 struct drbd_interval
*i
= &req
->i
;
204 drbd_remove_interval(root
, i
);
206 /* Wake up any processes waiting for this request to complete. */
208 wake_up(&mdev
->misc_wait
);
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.
217 void _req_may_be_done(struct drbd_request
*req
, struct bio_and_error
*m
)
219 const unsigned long s
= req
->rq_state
;
220 struct drbd_conf
*mdev
= req
->w
.mdev
;
221 int rw
= req
->rq_state
& RQ_WRITE
? WRITE
: READ
;
223 /* we must not complete the master bio, while it is
224 * still being processed by _drbd_send_zc_bio (drbd_send_dblock)
225 * not yet acknowledged by the peer
226 * not yet completed by the local io subsystem
227 * these flags may get cleared in any order by
230 * the bio_endio completion callbacks.
232 if (s
& RQ_LOCAL_PENDING
&& !(s
& RQ_LOCAL_ABORTED
))
234 if (req
->i
.waiting
) {
235 /* Retry all conflicting peer requests. */
236 wake_up(&mdev
->misc_wait
);
238 if (s
& RQ_NET_QUEUED
)
240 if (s
& RQ_NET_PENDING
)
243 if (req
->master_bio
) {
244 /* this is DATA_RECEIVED (remote read)
245 * or protocol C P_WRITE_ACK
246 * or protocol B P_RECV_ACK
247 * or protocol A "HANDED_OVER_TO_NETWORK" (SendAck)
248 * or canceled or failed,
249 * or killed from the transfer log due to connection loss.
253 * figure out whether to report success or failure.
255 * report success when at least one of the operations succeeded.
256 * or, to put the other way,
257 * only report failure, when both operations failed.
259 * what to do about the failures is handled elsewhere.
260 * what we need to do here is just: complete the master_bio.
262 * local completion error, if any, has been stored as ERR_PTR
263 * in private_bio within drbd_request_endio.
265 int ok
= (s
& RQ_LOCAL_OK
) || (s
& RQ_NET_OK
);
266 int error
= PTR_ERR(req
->private_bio
);
268 /* remove the request from the conflict detection
269 * respective block_id verification hash */
270 if (!drbd_interval_empty(&req
->i
)) {
271 struct rb_root
*root
;
274 root
= &mdev
->write_requests
;
276 root
= &mdev
->read_requests
;
277 drbd_remove_request_interval(root
, req
);
278 } else if (!(s
& RQ_POSTPONED
))
279 D_ASSERT((s
& (RQ_NET_MASK
& ~RQ_NET_DONE
)) == 0);
281 /* for writes we need to do some extra housekeeping */
283 _about_to_complete_local_write(mdev
, req
);
285 /* Update disk stats */
286 _drbd_end_io_acct(mdev
, req
);
288 if (!(s
& RQ_POSTPONED
)) {
289 m
->error
= ok
? 0 : (error
?: -EIO
);
290 m
->bio
= req
->master_bio
;
292 req
->master_bio
= NULL
;
295 if (s
& RQ_LOCAL_PENDING
)
298 if ((s
& RQ_NET_MASK
) == 0 || (s
& RQ_NET_DONE
)) {
299 /* this is disconnected (local only) operation,
300 * or protocol A, B, or C P_BARRIER_ACK,
301 * or killed from the transfer log due to connection loss. */
302 _req_is_done(mdev
, req
, rw
);
304 /* else: network part and not DONE yet. that is
305 * protocol A, B, or C, barrier ack still pending... */
308 static void _req_may_be_done_not_susp(struct drbd_request
*req
, struct bio_and_error
*m
)
310 struct drbd_conf
*mdev
= req
->w
.mdev
;
312 if (!drbd_suspended(mdev
))
313 _req_may_be_done(req
, m
);
316 /* obviously this could be coded as many single functions
317 * instead of one huge switch,
318 * or by putting the code directly in the respective locations
319 * (as it has been before).
321 * but having it this way
322 * enforces that it is all in this one place, where it is easier to audit,
323 * it makes it obvious that whatever "event" "happens" to a request should
324 * happen "atomically" within the req_lock,
325 * and it enforces that we have to think in a very structured manner
326 * about the "events" that may happen to a request during its life time ...
328 int __req_mod(struct drbd_request
*req
, enum drbd_req_event what
,
329 struct bio_and_error
*m
)
331 struct drbd_conf
*mdev
= req
->w
.mdev
;
340 dev_err(DEV
, "LOGIC BUG in %s:%u\n", __FILE__
, __LINE__
);
343 /* does not happen...
344 * initialization done in drbd_req_new
349 case TO_BE_SENT
: /* via network */
350 /* reached via __drbd_make_request
351 * and from w_read_retry_remote */
352 D_ASSERT(!(req
->rq_state
& RQ_NET_MASK
));
353 req
->rq_state
|= RQ_NET_PENDING
;
355 nc
= rcu_dereference(mdev
->tconn
->net_conf
);
356 p
= nc
->wire_protocol
;
359 p
== DRBD_PROT_C
? RQ_EXP_WRITE_ACK
:
360 p
== DRBD_PROT_B
? RQ_EXP_RECEIVE_ACK
: 0;
361 inc_ap_pending(mdev
);
364 case TO_BE_SUBMITTED
: /* locally */
365 /* reached via __drbd_make_request */
366 D_ASSERT(!(req
->rq_state
& RQ_LOCAL_MASK
));
367 req
->rq_state
|= RQ_LOCAL_PENDING
;
371 if (req
->rq_state
& RQ_WRITE
)
372 mdev
->writ_cnt
+= req
->i
.size
>> 9;
374 mdev
->read_cnt
+= req
->i
.size
>> 9;
376 req
->rq_state
|= (RQ_LOCAL_COMPLETED
|RQ_LOCAL_OK
);
377 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
379 _req_may_be_done_not_susp(req
, m
);
384 req
->rq_state
|= RQ_LOCAL_ABORTED
;
385 if (req
->rq_state
& RQ_WRITE
)
386 _req_may_be_done_not_susp(req
, m
);
388 goto goto_queue_for_net_read
;
391 case WRITE_COMPLETED_WITH_ERROR
:
392 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
393 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
395 __drbd_chk_io_error(mdev
, false);
396 _req_may_be_done_not_susp(req
, m
);
400 case READ_AHEAD_COMPLETED_WITH_ERROR
:
401 /* it is legal to fail READA */
402 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
403 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
404 _req_may_be_done_not_susp(req
, m
);
408 case READ_COMPLETED_WITH_ERROR
:
409 drbd_set_out_of_sync(mdev
, req
->i
.sector
, req
->i
.size
);
411 req
->rq_state
|= RQ_LOCAL_COMPLETED
;
412 req
->rq_state
&= ~RQ_LOCAL_PENDING
;
414 D_ASSERT(!(req
->rq_state
& RQ_NET_MASK
));
416 __drbd_chk_io_error(mdev
, false);
419 goto_queue_for_net_read
:
421 /* no point in retrying if there is no good remote data,
422 * or we have no connection. */
423 if (mdev
->state
.pdsk
!= D_UP_TO_DATE
) {
424 _req_may_be_done_not_susp(req
, m
);
428 /* _req_mod(req,TO_BE_SENT); oops, recursion... */
429 req
->rq_state
|= RQ_NET_PENDING
;
430 inc_ap_pending(mdev
);
431 /* fall through: _req_mod(req,QUEUE_FOR_NET_READ); */
433 case QUEUE_FOR_NET_READ
:
434 /* READ or READA, and
436 * or target area marked as invalid,
437 * or just got an io-error. */
438 /* from __drbd_make_request
439 * or from bio_endio during read io-error recovery */
441 /* so we can verify the handle in the answer packet
442 * corresponding hlist_del is in _req_may_be_done() */
443 D_ASSERT(drbd_interval_empty(&req
->i
));
444 drbd_insert_interval(&mdev
->read_requests
, &req
->i
);
446 set_bit(UNPLUG_REMOTE
, &mdev
->flags
);
448 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
449 req
->rq_state
|= RQ_NET_QUEUED
;
450 req
->w
.cb
= (req
->rq_state
& RQ_LOCAL_MASK
)
451 ? w_read_retry_remote
453 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
456 case QUEUE_FOR_NET_WRITE
:
457 /* assert something? */
458 /* from __drbd_make_request only */
460 /* corresponding hlist_del is in _req_may_be_done() */
461 D_ASSERT(drbd_interval_empty(&req
->i
));
462 drbd_insert_interval(&mdev
->write_requests
, &req
->i
);
465 * In case the req ended up on the transfer log before being
466 * queued on the worker, it could lead to this request being
467 * missed during cleanup after connection loss.
468 * So we have to do both operations here,
469 * within the same lock that protects the transfer log.
471 * _req_add_to_epoch(req); this has to be after the
472 * _maybe_start_new_epoch(req); which happened in
473 * __drbd_make_request, because we now may set the bit
474 * again ourselves to close the current epoch.
476 * Add req to the (now) current epoch (barrier). */
478 /* otherwise we may lose an unplug, which may cause some remote
479 * io-scheduler timeout to expire, increasing maximum latency,
480 * hurting performance. */
481 set_bit(UNPLUG_REMOTE
, &mdev
->flags
);
483 /* see __drbd_make_request,
484 * just after it grabs the req_lock */
485 D_ASSERT(test_bit(CREATE_BARRIER
, &mdev
->tconn
->flags
) == 0);
487 req
->epoch
= mdev
->tconn
->newest_tle
->br_number
;
489 /* increment size of current epoch */
490 mdev
->tconn
->newest_tle
->n_writes
++;
492 /* queue work item to send data */
493 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
494 req
->rq_state
|= RQ_NET_QUEUED
;
495 req
->w
.cb
= w_send_dblock
;
496 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
498 /* close the epoch, in case it outgrew the limit */
500 nc
= rcu_dereference(mdev
->tconn
->net_conf
);
501 p
= nc
->max_epoch_size
;
503 if (mdev
->tconn
->newest_tle
->n_writes
>= p
)
508 case QUEUE_FOR_SEND_OOS
:
509 req
->rq_state
|= RQ_NET_QUEUED
;
510 req
->w
.cb
= w_send_out_of_sync
;
511 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
514 case OOS_HANDED_TO_NETWORK
:
515 /* actually the same */
517 /* treat it the same */
519 /* real cleanup will be done from tl_clear. just update flags
520 * so it is no longer marked as on the worker queue */
521 req
->rq_state
&= ~RQ_NET_QUEUED
;
522 /* if we did it right, tl_clear should be scheduled only after
523 * this, so this should not be necessary! */
524 _req_may_be_done_not_susp(req
, m
);
527 case HANDED_OVER_TO_NETWORK
:
528 /* assert something? */
529 if (bio_data_dir(req
->master_bio
) == WRITE
)
530 atomic_add(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
532 if (bio_data_dir(req
->master_bio
) == WRITE
&&
533 !(req
->rq_state
& (RQ_EXP_RECEIVE_ACK
| RQ_EXP_WRITE_ACK
))) {
534 /* this is what is dangerous about protocol A:
535 * pretend it was successfully written on the peer. */
536 if (req
->rq_state
& RQ_NET_PENDING
) {
537 dec_ap_pending(mdev
);
538 req
->rq_state
&= ~RQ_NET_PENDING
;
539 req
->rq_state
|= RQ_NET_OK
;
540 } /* else: neg-ack was faster... */
541 /* it is still not yet RQ_NET_DONE until the
542 * corresponding epoch barrier got acked as well,
543 * so we know what to dirty on connection loss */
545 req
->rq_state
&= ~RQ_NET_QUEUED
;
546 req
->rq_state
|= RQ_NET_SENT
;
547 /* because _drbd_send_zc_bio could sleep, and may want to
548 * dereference the bio even after the "WRITE_ACKED_BY_PEER" and
549 * "COMPLETED_OK" events came in, once we return from
550 * _drbd_send_zc_bio (drbd_send_dblock), we have to check
551 * whether it is done already, and end it. */
552 _req_may_be_done_not_susp(req
, m
);
555 case READ_RETRY_REMOTE_CANCELED
:
556 req
->rq_state
&= ~RQ_NET_QUEUED
;
557 /* fall through, in case we raced with drbd_disconnect */
558 case CONNECTION_LOST_WHILE_PENDING
:
559 /* transfer log cleanup after connection loss */
560 /* assert something? */
561 if (req
->rq_state
& RQ_NET_PENDING
)
562 dec_ap_pending(mdev
);
564 p
= !(req
->rq_state
& RQ_WRITE
) && req
->rq_state
& RQ_NET_PENDING
;
566 req
->rq_state
&= ~(RQ_NET_OK
|RQ_NET_PENDING
);
567 req
->rq_state
|= RQ_NET_DONE
;
568 if (req
->rq_state
& RQ_NET_SENT
&& req
->rq_state
& RQ_WRITE
)
569 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
571 /* if it is still queued, we may not complete it here.
572 * it will be canceled soon. */
573 if (!(req
->rq_state
& RQ_NET_QUEUED
)) {
575 goto goto_read_retry_local
;
576 _req_may_be_done(req
, m
); /* Allowed while state.susp */
580 case WRITE_ACKED_BY_PEER_AND_SIS
:
581 req
->rq_state
|= RQ_NET_SIS
;
583 /* for discarded conflicting writes of multiple primaries,
584 * there is no need to keep anything in the tl, potential
585 * node crashes are covered by the activity log. */
586 req
->rq_state
|= RQ_NET_DONE
;
588 case WRITE_ACKED_BY_PEER
:
589 D_ASSERT(req
->rq_state
& RQ_EXP_WRITE_ACK
);
590 /* protocol C; successfully written on peer.
591 * Nothing to do here.
592 * We want to keep the tl in place for all protocols, to cater
593 * for volatile write-back caches on lower level devices.
595 * A barrier request is expected to have forced all prior
596 * requests onto stable storage, so completion of a barrier
597 * request could set NET_DONE right here, and not wait for the
598 * P_BARRIER_ACK, but that is an unnecessary optimization. */
601 /* this makes it effectively the same as for: */
602 case RECV_ACKED_BY_PEER
:
603 D_ASSERT(req
->rq_state
& RQ_EXP_RECEIVE_ACK
);
604 /* protocol B; pretends to be successfully written on peer.
605 * see also notes above in HANDED_OVER_TO_NETWORK about
608 req
->rq_state
|= RQ_NET_OK
;
609 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
610 dec_ap_pending(mdev
);
611 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
612 req
->rq_state
&= ~RQ_NET_PENDING
;
613 _req_may_be_done_not_susp(req
, m
);
617 D_ASSERT(req
->rq_state
& RQ_EXP_WRITE_ACK
);
618 /* If this node has already detected the write conflict, the
619 * worker will be waiting on misc_wait. Wake it up once this
620 * request has completed locally.
622 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
623 req
->rq_state
|= RQ_POSTPONED
;
624 _req_may_be_done_not_susp(req
, m
);
628 /* assert something? */
629 if (req
->rq_state
& RQ_NET_PENDING
) {
630 dec_ap_pending(mdev
);
631 if (req
->rq_state
& RQ_WRITE
)
632 atomic_sub(req
->i
.size
>> 9, &mdev
->ap_in_flight
);
634 req
->rq_state
&= ~(RQ_NET_OK
|RQ_NET_PENDING
);
636 req
->rq_state
|= RQ_NET_DONE
;
638 if (!(req
->rq_state
& RQ_WRITE
))
639 goto goto_read_retry_local
;
641 _req_may_be_done_not_susp(req
, m
);
642 /* else: done by HANDED_OVER_TO_NETWORK */
645 goto_read_retry_local
:
646 if (!drbd_may_do_local_read(mdev
, req
->i
.sector
, req
->i
.size
)) {
647 _req_may_be_done_not_susp(req
, m
);
650 D_ASSERT(!(req
->rq_state
& RQ_LOCAL_PENDING
));
651 req
->rq_state
|= RQ_LOCAL_PENDING
;
654 req
->w
.cb
= w_restart_disk_io
;
655 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
658 case FAIL_FROZEN_DISK_IO
:
659 if (!(req
->rq_state
& RQ_LOCAL_COMPLETED
))
662 _req_may_be_done(req
, m
); /* Allowed while state.susp */
665 case RESTART_FROZEN_DISK_IO
:
666 if (!(req
->rq_state
& RQ_LOCAL_COMPLETED
))
669 req
->rq_state
&= ~RQ_LOCAL_COMPLETED
;
672 if (bio_data_dir(req
->master_bio
) == WRITE
)
676 req
->w
.cb
= w_restart_disk_io
;
677 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
681 /* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK
682 before the connection loss (B&C only); only P_BARRIER_ACK was missing.
683 Trowing them out of the TL here by pretending we got a BARRIER_ACK
684 We ensure that the peer was not rebooted */
685 if (!(req
->rq_state
& RQ_NET_OK
)) {
687 drbd_queue_work(&mdev
->tconn
->data
.work
, &req
->w
);
688 rv
= req
->rq_state
& RQ_WRITE
? MR_WRITE
: MR_READ
;
692 /* else, fall through to BARRIER_ACKED */
695 if (!(req
->rq_state
& RQ_WRITE
))
698 if (req
->rq_state
& RQ_NET_PENDING
) {
699 /* barrier came in before all requests were acked.
700 * this is bad, because if the connection is lost now,
701 * we won't be able to clean them up... */
702 dev_err(DEV
, "FIXME (BARRIER_ACKED but pending)\n");
703 list_move(&req
->tl_requests
, &mdev
->tconn
->out_of_sequence_requests
);
705 if ((req
->rq_state
& RQ_NET_MASK
) != 0) {
706 req
->rq_state
|= RQ_NET_DONE
;
707 if (!(req
->rq_state
& (RQ_EXP_RECEIVE_ACK
| RQ_EXP_WRITE_ACK
)))
708 atomic_sub(req
->i
.size
>>9, &mdev
->ap_in_flight
);
710 _req_may_be_done(req
, m
); /* Allowed while state.susp */
714 D_ASSERT(req
->rq_state
& RQ_NET_PENDING
);
715 dec_ap_pending(mdev
);
716 req
->rq_state
&= ~RQ_NET_PENDING
;
717 req
->rq_state
|= (RQ_NET_OK
|RQ_NET_DONE
);
718 _req_may_be_done_not_susp(req
, m
);
725 /* we may do a local read if:
726 * - we are consistent (of course),
727 * - or we are generally inconsistent,
728 * BUT we are still/already IN SYNC for this area.
729 * since size may be bigger than BM_BLOCK_SIZE,
730 * we may need to check several bits.
732 static bool drbd_may_do_local_read(struct drbd_conf
*mdev
, sector_t sector
, int size
)
734 unsigned long sbnr
, ebnr
;
735 sector_t esector
, nr_sectors
;
737 if (mdev
->state
.disk
== D_UP_TO_DATE
)
739 if (mdev
->state
.disk
!= D_INCONSISTENT
)
741 esector
= sector
+ (size
>> 9) - 1;
742 nr_sectors
= drbd_get_capacity(mdev
->this_bdev
);
743 D_ASSERT(sector
< nr_sectors
);
744 D_ASSERT(esector
< nr_sectors
);
746 sbnr
= BM_SECT_TO_BIT(sector
);
747 ebnr
= BM_SECT_TO_BIT(esector
);
749 return drbd_bm_count_bits(mdev
, sbnr
, ebnr
) == 0;
752 static bool remote_due_to_read_balancing(struct drbd_conf
*mdev
, sector_t sector
)
754 enum drbd_read_balancing rbm
;
755 struct backing_dev_info
*bdi
;
758 if (mdev
->state
.pdsk
< D_UP_TO_DATE
)
762 rbm
= rcu_dereference(mdev
->ldev
->disk_conf
)->read_balancing
;
766 case RB_CONGESTED_REMOTE
:
767 bdi
= &mdev
->ldev
->backing_bdev
->bd_disk
->queue
->backing_dev_info
;
768 return bdi_read_congested(bdi
);
769 case RB_LEAST_PENDING
:
770 return atomic_read(&mdev
->local_cnt
) >
771 atomic_read(&mdev
->ap_pending_cnt
) + atomic_read(&mdev
->rs_pending_cnt
);
772 case RB_32K_STRIPING
: /* stripe_shift = 15 */
773 case RB_64K_STRIPING
:
774 case RB_128K_STRIPING
:
775 case RB_256K_STRIPING
:
776 case RB_512K_STRIPING
:
777 case RB_1M_STRIPING
: /* stripe_shift = 20 */
778 stripe_shift
= (rbm
- RB_32K_STRIPING
+ 15);
779 return (sector
>> (stripe_shift
- 9)) & 1;
781 return test_and_change_bit(READ_BALANCE_RR
, &mdev
->flags
);
782 case RB_PREFER_REMOTE
:
784 case RB_PREFER_LOCAL
:
791 * complete_conflicting_writes - wait for any conflicting write requests
793 * The write_requests tree contains all active write requests which we
794 * currently know about. Wait for any requests to complete which conflict with
797 static int complete_conflicting_writes(struct drbd_conf
*mdev
,
798 sector_t sector
, int size
)
801 struct drbd_interval
*i
;
804 i
= drbd_find_overlap(&mdev
->write_requests
, sector
, size
);
807 err
= drbd_wait_misc(mdev
, i
);
813 int __drbd_make_request(struct drbd_conf
*mdev
, struct bio
*bio
, unsigned long start_time
)
815 const int rw
= bio_rw(bio
);
816 const int size
= bio
->bi_size
;
817 const sector_t sector
= bio
->bi_sector
;
818 struct drbd_tl_epoch
*b
= NULL
;
819 struct drbd_request
*req
;
821 int local
, remote
, send_oos
= 0;
825 /* allocate outside of all locks; */
826 req
= drbd_req_new(mdev
, bio
);
829 /* only pass the error to the upper layers.
830 * if user cannot handle io errors, that's not our business. */
831 dev_err(DEV
, "could not kmalloc() req\n");
832 bio_endio(bio
, -ENOMEM
);
835 req
->start_time
= start_time
;
837 local
= get_ldev(mdev
);
839 bio_put(req
->private_bio
); /* or we get a bio leak */
840 req
->private_bio
= NULL
;
847 if (!drbd_may_do_local_read(mdev
, sector
, size
) ||
848 remote_due_to_read_balancing(mdev
, sector
)) {
849 /* we could kick the syncer to
850 * sync this extent asap, wait for
851 * it, then continue locally.
852 * Or just issue the request remotely.
855 bio_put(req
->private_bio
);
856 req
->private_bio
= NULL
;
860 remote
= !local
&& mdev
->state
.pdsk
>= D_UP_TO_DATE
;
863 /* If we have a disk, but a READA request is mapped to remote,
864 * we are R_PRIMARY, D_INCONSISTENT, SyncTarget.
865 * Just fail that READA request right here.
867 * THINK: maybe fail all READA when not local?
868 * or make this configurable...
869 * if network is slow, READA won't do any good.
871 if (rw
== READA
&& mdev
->state
.disk
>= D_INCONSISTENT
&& !local
) {
873 goto fail_and_free_req
;
876 /* For WRITES going to the local disk, grab a reference on the target
877 * extent. This waits for any resync activity in the corresponding
878 * resync extent to finish, and, if necessary, pulls in the target
879 * extent into the activity log, which involves further disk io because
880 * of transactional on-disk meta data updates. */
881 if (rw
== WRITE
&& local
&& !test_bit(AL_SUSPENDED
, &mdev
->flags
)) {
882 req
->rq_state
|= RQ_IN_ACT_LOG
;
883 drbd_al_begin_io(mdev
, &req
->i
);
886 remote
= remote
&& drbd_should_do_remote(mdev
->state
);
887 send_oos
= rw
== WRITE
&& drbd_should_send_out_of_sync(mdev
->state
);
888 D_ASSERT(!(remote
&& send_oos
));
890 if (!(local
|| remote
) && !drbd_suspended(mdev
)) {
891 if (__ratelimit(&drbd_ratelimit_state
))
892 dev_err(DEV
, "IO ERROR: neither local nor remote disk\n");
894 goto fail_free_complete
;
897 /* For WRITE request, we have to make sure that we have an
898 * unused_spare_tle, in case we need to start a new epoch.
899 * I try to be smart and avoid to pre-allocate always "just in case",
900 * but there is a race between testing the bit and pointer outside the
901 * spinlock, and grabbing the spinlock.
902 * if we lost that race, we retry. */
903 if (rw
== WRITE
&& (remote
|| send_oos
) &&
904 mdev
->tconn
->unused_spare_tle
== NULL
&&
905 test_bit(CREATE_BARRIER
, &mdev
->tconn
->flags
)) {
907 b
= kmalloc(sizeof(struct drbd_tl_epoch
), GFP_NOIO
);
909 dev_err(DEV
, "Failed to alloc barrier.\n");
911 goto fail_free_complete
;
915 /* GOOD, everything prepared, grab the spin_lock */
916 spin_lock_irq(&mdev
->tconn
->req_lock
);
919 err
= complete_conflicting_writes(mdev
, sector
, size
);
921 if (err
!= -ERESTARTSYS
)
922 _conn_request_state(mdev
->tconn
,
925 spin_unlock_irq(&mdev
->tconn
->req_lock
);
927 goto fail_free_complete
;
931 if (drbd_suspended(mdev
)) {
932 /* If we got suspended, use the retry mechanism in
933 drbd_make_request() to restart processing of this
934 bio. In the next call to drbd_make_request
935 we sleep in inc_ap_bio() */
937 spin_unlock_irq(&mdev
->tconn
->req_lock
);
938 goto fail_free_complete
;
941 if (remote
|| send_oos
) {
942 remote
= drbd_should_do_remote(mdev
->state
);
943 send_oos
= rw
== WRITE
&& drbd_should_send_out_of_sync(mdev
->state
);
944 D_ASSERT(!(remote
&& send_oos
));
946 if (!(remote
|| send_oos
))
947 dev_warn(DEV
, "lost connection while grabbing the req_lock!\n");
948 if (!(local
|| remote
)) {
949 dev_err(DEV
, "IO ERROR: neither local nor remote disk\n");
950 spin_unlock_irq(&mdev
->tconn
->req_lock
);
952 goto fail_free_complete
;
956 if (b
&& mdev
->tconn
->unused_spare_tle
== NULL
) {
957 mdev
->tconn
->unused_spare_tle
= b
;
960 if (rw
== WRITE
&& (remote
|| send_oos
) &&
961 mdev
->tconn
->unused_spare_tle
== NULL
&&
962 test_bit(CREATE_BARRIER
, &mdev
->tconn
->flags
)) {
963 /* someone closed the current epoch
964 * while we were grabbing the spinlock */
965 spin_unlock_irq(&mdev
->tconn
->req_lock
);
966 goto allocate_barrier
;
970 /* Update disk stats */
971 _drbd_start_io_acct(mdev
, req
, bio
);
973 /* _maybe_start_new_epoch(mdev);
974 * If we need to generate a write barrier packet, we have to add the
975 * new epoch (barrier) object, and queue the barrier packet for sending,
976 * and queue the req's data after it _within the same lock_, otherwise
977 * we have race conditions were the reorder domains could be mixed up.
979 * Even read requests may start a new epoch and queue the corresponding
980 * barrier packet. To get the write ordering right, we only have to
981 * make sure that, if this is a write request and it triggered a
982 * barrier packet, this request is queued within the same spinlock. */
983 if ((remote
|| send_oos
) && mdev
->tconn
->unused_spare_tle
&&
984 test_and_clear_bit(CREATE_BARRIER
, &mdev
->tconn
->flags
)) {
985 _tl_add_barrier(mdev
->tconn
, mdev
->tconn
->unused_spare_tle
);
986 mdev
->tconn
->unused_spare_tle
= NULL
;
988 D_ASSERT(!(remote
&& rw
== WRITE
&&
989 test_bit(CREATE_BARRIER
, &mdev
->tconn
->flags
)));
993 * Actually, 'local' may be wrong here already, since we may have failed
994 * to write to the meta data, and may become wrong anytime because of
995 * local io-error for some other request, which would lead to us
996 * "detaching" the local disk.
998 * 'remote' may become wrong any time because the network could fail.
1000 * This is a harmless race condition, though, since it is handled
1001 * correctly at the appropriate places; so it just defers the failure
1002 * of the respective operation.
1005 /* mark them early for readability.
1006 * this just sets some state flags. */
1008 _req_mod(req
, TO_BE_SENT
);
1010 _req_mod(req
, TO_BE_SUBMITTED
);
1012 list_add_tail(&req
->tl_requests
, &mdev
->tconn
->newest_tle
->requests
);
1014 /* NOTE remote first: to get the concurrent write detection right,
1015 * we must register the request before start of local IO. */
1017 /* either WRITE and C_CONNECTED,
1018 * or READ, and no local disk,
1019 * or READ, but not in sync.
1021 _req_mod(req
, (rw
== WRITE
)
1022 ? QUEUE_FOR_NET_WRITE
1023 : QUEUE_FOR_NET_READ
);
1025 if (send_oos
&& drbd_set_out_of_sync(mdev
, sector
, size
))
1026 _req_mod(req
, QUEUE_FOR_SEND_OOS
);
1029 nc
= rcu_dereference(mdev
->tconn
->net_conf
);
1031 nc
->on_congestion
!= OC_BLOCK
&& mdev
->tconn
->agreed_pro_version
>= 96) {
1034 if (nc
->cong_fill
&&
1035 atomic_read(&mdev
->ap_in_flight
) >= nc
->cong_fill
) {
1036 dev_info(DEV
, "Congestion-fill threshold reached\n");
1040 if (mdev
->act_log
->used
>= nc
->cong_extents
) {
1041 dev_info(DEV
, "Congestion-extents threshold reached\n");
1046 queue_barrier(mdev
); /* last barrier, after mirrored writes */
1048 if (nc
->on_congestion
== OC_PULL_AHEAD
)
1049 _drbd_set_state(_NS(mdev
, conn
, C_AHEAD
), 0, NULL
);
1050 else /*nc->on_congestion == OC_DISCONNECT */
1051 _drbd_set_state(_NS(mdev
, conn
, C_DISCONNECTING
), 0, NULL
);
1056 spin_unlock_irq(&mdev
->tconn
->req_lock
);
1057 kfree(b
); /* if someone else has beaten us to it... */
1060 req
->private_bio
->bi_bdev
= mdev
->ldev
->backing_bdev
;
1062 /* State may have changed since we grabbed our reference on the
1063 * mdev->ldev member. Double check, and short-circuit to endio.
1064 * In case the last activity log transaction failed to get on
1065 * stable storage, and this is a WRITE, we may not even submit
1067 if (get_ldev(mdev
)) {
1068 if (drbd_insert_fault(mdev
, rw
== WRITE
? DRBD_FAULT_DT_WR
1069 : rw
== READ
? DRBD_FAULT_DT_RD
1070 : DRBD_FAULT_DT_RA
))
1071 bio_endio(req
->private_bio
, -EIO
);
1073 generic_make_request(req
->private_bio
);
1076 bio_endio(req
->private_bio
, -EIO
);
1082 if (req
->rq_state
& RQ_IN_ACT_LOG
)
1083 drbd_al_complete_io(mdev
, &req
->i
);
1086 bio_put(req
->private_bio
);
1087 req
->private_bio
= NULL
;
1091 bio_endio(bio
, err
);
1100 int drbd_make_request(struct request_queue
*q
, struct bio
*bio
)
1102 struct drbd_conf
*mdev
= (struct drbd_conf
*) q
->queuedata
;
1103 unsigned long start_time
;
1105 start_time
= jiffies
;
1108 * what we "blindly" assume:
1110 D_ASSERT(bio
->bi_size
> 0);
1111 D_ASSERT(IS_ALIGNED(bio
->bi_size
, 512));
1115 } while (__drbd_make_request(mdev
, bio
, start_time
));
1120 /* This is called by bio_add_page().
1122 * q->max_hw_sectors and other global limits are already enforced there.
1124 * We need to call down to our lower level device,
1125 * in case it has special restrictions.
1127 * We also may need to enforce configured max-bio-bvecs limits.
1129 * As long as the BIO is empty we have to allow at least one bvec,
1130 * regardless of size and offset, so no need to ask lower levels.
1132 int drbd_merge_bvec(struct request_queue
*q
, struct bvec_merge_data
*bvm
, struct bio_vec
*bvec
)
1134 struct drbd_conf
*mdev
= (struct drbd_conf
*) q
->queuedata
;
1135 unsigned int bio_size
= bvm
->bi_size
;
1136 int limit
= DRBD_MAX_BIO_SIZE
;
1139 if (bio_size
&& get_ldev(mdev
)) {
1140 struct request_queue
* const b
=
1141 mdev
->ldev
->backing_bdev
->bd_disk
->queue
;
1142 if (b
->merge_bvec_fn
) {
1143 backing_limit
= b
->merge_bvec_fn(b
, bvm
, bvec
);
1144 limit
= min(limit
, backing_limit
);
1151 void request_timer_fn(unsigned long data
)
1153 struct drbd_conf
*mdev
= (struct drbd_conf
*) data
;
1154 struct drbd_tconn
*tconn
= mdev
->tconn
;
1155 struct drbd_request
*req
; /* oldest request */
1156 struct block_device
*bdev
;
1157 struct list_head
*le
;
1158 struct net_conf
*nc
;
1159 unsigned long ent
= 0, dt
= 0, et
, nt
; /* effective timeout = ko_count * timeout */
1162 nc
= rcu_dereference(tconn
->net_conf
);
1163 ent
= nc
? nc
->timeout
* HZ
/10 * nc
->ko_count
: 0;
1165 if (get_ldev(mdev
)) {
1166 dt
= rcu_dereference(mdev
->ldev
->disk_conf
)->disk_timeout
* HZ
/ 10;
1167 bdev
= mdev
->ldev
->backing_bdev
;
1172 et
= min_not_zero(dt
, ent
);
1174 if (!et
|| (mdev
->state
.conn
< C_WF_REPORT_PARAMS
&& mdev
->state
.disk
<= D_FAILED
))
1175 return; /* Recurring timer stopped */
1177 spin_lock_irq(&tconn
->req_lock
);
1178 le
= &tconn
->oldest_tle
->requests
;
1179 if (list_empty(le
)) {
1180 spin_unlock_irq(&tconn
->req_lock
);
1181 mod_timer(&mdev
->request_timer
, jiffies
+ et
);
1186 req
= list_entry(le
, struct drbd_request
, tl_requests
);
1187 if (ent
&& req
->rq_state
& RQ_NET_PENDING
) {
1188 if (time_is_before_eq_jiffies(req
->start_time
+ ent
)) {
1189 dev_warn(DEV
, "Remote failed to finish a request within ko-count * timeout\n");
1190 _drbd_set_state(_NS(mdev
, conn
, C_TIMEOUT
), CS_VERBOSE
| CS_HARD
, NULL
);
1193 if (dt
&& req
->rq_state
& RQ_LOCAL_PENDING
&& req
->private_bio
->bi_bdev
== bdev
) {
1194 if (time_is_before_eq_jiffies(req
->start_time
+ dt
)) {
1195 dev_warn(DEV
, "Local backing device failed to meet the disk-timeout\n");
1196 __drbd_chk_io_error(mdev
, 1);
1199 nt
= (time_is_before_eq_jiffies(req
->start_time
+ et
) ? jiffies
: req
->start_time
) + et
;
1200 spin_unlock_irq(&tconn
->req_lock
);
1201 mod_timer(&mdev
->request_timer
, nt
);