1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2003 Sistina Software Limited.
4 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
5 *
6 * This file is released under the GPL.
7 */
8
9#include "dm-bio-record.h"
10
11#include <linux/init.h>
12#include <linux/mempool.h>
13#include <linux/module.h>
14#include <linux/pagemap.h>
15#include <linux/slab.h>
16#include <linux/workqueue.h>
17#include <linux/device-mapper.h>
18#include <linux/dm-io.h>
19#include <linux/dm-dirty-log.h>
20#include <linux/dm-kcopyd.h>
21#include <linux/dm-region-hash.h>
22
23static struct workqueue_struct *dm_raid1_wq;
24
25#define DM_MSG_PREFIX "raid1"
26
27#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
28
29#define MAX_NR_MIRRORS (DM_KCOPYD_MAX_REGIONS + 1)
30
31#define DM_RAID1_HANDLE_ERRORS 0x01
32#define DM_RAID1_KEEP_LOG 0x02
33#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
34#define keep_log(p) ((p)->features & DM_RAID1_KEEP_LOG)
35
36static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
37
38/*
39 *---------------------------------------------------------------
40 * Mirror set structures.
41 *---------------------------------------------------------------
42 */
43enum dm_raid1_error {
44 DM_RAID1_WRITE_ERROR,
45 DM_RAID1_FLUSH_ERROR,
46 DM_RAID1_SYNC_ERROR,
47 DM_RAID1_READ_ERROR
48};
49
50struct mirror {
51 struct mirror_set *ms;
52 atomic_t error_count;
53 unsigned long error_type;
54 struct dm_dev *dev;
55 sector_t offset;
56};
57
58struct mirror_set {
59 struct dm_target *ti;
60 struct list_head list;
61
62 uint64_t features;
63
64 spinlock_t lock; /* protects the lists */
65 struct bio_list reads;
66 struct bio_list writes;
67 struct bio_list failures;
68 struct bio_list holds; /* bios are waiting until suspend */
69
70 struct dm_region_hash *rh;
71 struct dm_kcopyd_client *kcopyd_client;
72 struct dm_io_client *io_client;
73
74 /* recovery */
75 region_t nr_regions;
76 int in_sync;
77 int log_failure;
78 int leg_failure;
79 atomic_t suspend;
80
81 atomic_t default_mirror; /* Default mirror */
82
83 struct workqueue_struct *kmirrord_wq;
84 struct work_struct kmirrord_work;
85 struct timer_list timer;
86 unsigned long timer_pending;
87
88 struct work_struct trigger_event;
89
90 unsigned int nr_mirrors;
91 struct mirror mirror[];
92};
93
94DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle,
95 "A percentage of time allocated for raid resynchronization");
96
97static void wakeup_mirrord(void *context)
98{
99 struct mirror_set *ms = context;
100
101 queue_work(wq: ms->kmirrord_wq, work: &ms->kmirrord_work);
102}
103
104static void delayed_wake_fn(struct timer_list *t)
105{
106 struct mirror_set *ms = timer_container_of(ms, t, timer);
107
108 clear_bit(nr: 0, addr: &ms->timer_pending);
109 wakeup_mirrord(context: ms);
110}
111
112static void delayed_wake(struct mirror_set *ms)
113{
114 if (test_and_set_bit(nr: 0, addr: &ms->timer_pending))
115 return;
116
117 ms->timer.expires = jiffies + HZ / 5;
118 add_timer(timer: &ms->timer);
119}
120
121static void wakeup_all_recovery_waiters(void *context)
122{
123 wake_up_all(&_kmirrord_recovery_stopped);
124}
125
126static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
127{
128 unsigned long flags;
129 int should_wake = 0;
130 struct bio_list *bl;
131
132 bl = (rw == WRITE) ? &ms->writes : &ms->reads;
133 spin_lock_irqsave(&ms->lock, flags);
134 should_wake = !(bl->head);
135 bio_list_add(bl, bio);
136 if (should_wake)
137 wakeup_mirrord(context: ms);
138 spin_unlock_irqrestore(lock: &ms->lock, flags);
139}
140
141static void dispatch_bios(void *context, struct bio_list *bio_list)
142{
143 struct mirror_set *ms = context;
144 struct bio *bio;
145
146 while ((bio = bio_list_pop(bl: bio_list)))
147 queue_bio(ms, bio, WRITE);
148}
149
150struct dm_raid1_bio_record {
151 struct mirror *m;
152 /* if details->bi_bdev == NULL, details were not saved */
153 struct dm_bio_details details;
154 region_t write_region;
155};
156
157/*
158 * Every mirror should look like this one.
159 */
160#define DEFAULT_MIRROR 0
161
162/*
163 * This is yucky. We squirrel the mirror struct away inside
164 * bi_next for read/write buffers. This is safe since the bh
165 * doesn't get submitted to the lower levels of block layer.
166 */
167static struct mirror *bio_get_m(struct bio *bio)
168{
169 return (struct mirror *) bio->bi_next;
170}
171
172static void bio_set_m(struct bio *bio, struct mirror *m)
173{
174 bio->bi_next = (struct bio *) m;
175}
176
177static struct mirror *get_default_mirror(struct mirror_set *ms)
178{
179 return &ms->mirror[atomic_read(v: &ms->default_mirror)];
180}
181
182static void set_default_mirror(struct mirror *m)
183{
184 struct mirror_set *ms = m->ms;
185 struct mirror *m0 = &(ms->mirror[0]);
186
187 atomic_set(v: &ms->default_mirror, i: m - m0);
188}
189
190static struct mirror *get_valid_mirror(struct mirror_set *ms)
191{
192 struct mirror *m;
193
194 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
195 if (!atomic_read(v: &m->error_count))
196 return m;
197
198 return NULL;
199}
200
201/* fail_mirror
202 * @m: mirror device to fail
203 * @error_type: one of the enum's, DM_RAID1_*_ERROR
204 *
205 * If errors are being handled, record the type of
206 * error encountered for this device. If this type
207 * of error has already been recorded, we can return;
208 * otherwise, we must signal userspace by triggering
209 * an event. Additionally, if the device is the
210 * primary device, we must choose a new primary, but
211 * only if the mirror is in-sync.
212 *
213 * This function must not block.
214 */
215static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
216{
217 struct mirror_set *ms = m->ms;
218 struct mirror *new;
219
220 ms->leg_failure = 1;
221
222 /*
223 * error_count is used for nothing more than a
224 * simple way to tell if a device has encountered
225 * errors.
226 */
227 atomic_inc(v: &m->error_count);
228
229 if (test_and_set_bit(nr: error_type, addr: &m->error_type))
230 return;
231
232 if (!errors_handled(ms))
233 return;
234
235 if (m != get_default_mirror(ms))
236 goto out;
237
238 if (!ms->in_sync && !keep_log(ms)) {
239 /*
240 * Better to issue requests to same failing device
241 * than to risk returning corrupt data.
242 */
243 DMERR("Primary mirror (%s) failed while out-of-sync: Reads may fail.",
244 m->dev->name);
245 goto out;
246 }
247
248 new = get_valid_mirror(ms);
249 if (new)
250 set_default_mirror(new);
251 else
252 DMWARN("All sides of mirror have failed.");
253
254out:
255 queue_work(wq: dm_raid1_wq, work: &ms->trigger_event);
256}
257
258static int mirror_flush(struct dm_target *ti)
259{
260 struct mirror_set *ms = ti->private;
261 unsigned long error_bits;
262
263 unsigned int i;
264 struct dm_io_region io[MAX_NR_MIRRORS];
265 struct mirror *m;
266 struct dm_io_request io_req = {
267 .bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC,
268 .mem.type = DM_IO_KMEM,
269 .mem.ptr.addr = NULL,
270 .client = ms->io_client,
271 };
272
273 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
274 io[i].bdev = m->dev->bdev;
275 io[i].sector = 0;
276 io[i].count = 0;
277 }
278
279 error_bits = -1;
280 dm_io(io_req: &io_req, num_regions: ms->nr_mirrors, region: io, sync_error_bits: &error_bits, IOPRIO_DEFAULT);
281 if (unlikely(error_bits != 0)) {
282 for (i = 0; i < ms->nr_mirrors; i++)
283 if (test_bit(i, &error_bits))
284 fail_mirror(m: ms->mirror + i,
285 error_type: DM_RAID1_FLUSH_ERROR);
286 return -EIO;
287 }
288
289 return 0;
290}
291
292/*
293 *---------------------------------------------------------------
294 * Recovery.
295 *
296 * When a mirror is first activated we may find that some regions
297 * are in the no-sync state. We have to recover these by
298 * recopying from the default mirror to all the others.
299 *---------------------------------------------------------------
300 */
301static void recovery_complete(int read_err, unsigned long write_err,
302 void *context)
303{
304 struct dm_region *reg = context;
305 struct mirror_set *ms = dm_rh_region_context(reg);
306 int m, bit = 0;
307
308 if (read_err) {
309 /* Read error means the failure of default mirror. */
310 DMERR_LIMIT("Unable to read primary mirror during recovery");
311 fail_mirror(m: get_default_mirror(ms), error_type: DM_RAID1_SYNC_ERROR);
312 }
313
314 if (write_err) {
315 DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
316 write_err);
317 /*
318 * Bits correspond to devices (excluding default mirror).
319 * The default mirror cannot change during recovery.
320 */
321 for (m = 0; m < ms->nr_mirrors; m++) {
322 if (&ms->mirror[m] == get_default_mirror(ms))
323 continue;
324 if (test_bit(bit, &write_err))
325 fail_mirror(m: ms->mirror + m,
326 error_type: DM_RAID1_SYNC_ERROR);
327 bit++;
328 }
329 }
330
331 dm_rh_recovery_end(reg, error: !(read_err || write_err));
332}
333
334static void recover(struct mirror_set *ms, struct dm_region *reg)
335{
336 unsigned int i;
337 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
338 struct mirror *m;
339 unsigned long flags = 0;
340 region_t key = dm_rh_get_region_key(reg);
341 sector_t region_size = dm_rh_get_region_size(rh: ms->rh);
342
343 /* fill in the source */
344 m = get_default_mirror(ms);
345 from.bdev = m->dev->bdev;
346 from.sector = m->offset + dm_rh_region_to_sector(rh: ms->rh, region: key);
347 if (key == (ms->nr_regions - 1)) {
348 /*
349 * The final region may be smaller than
350 * region_size.
351 */
352 from.count = ms->ti->len & (region_size - 1);
353 if (!from.count)
354 from.count = region_size;
355 } else
356 from.count = region_size;
357
358 /* fill in the destinations */
359 for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
360 if (&ms->mirror[i] == get_default_mirror(ms))
361 continue;
362
363 m = ms->mirror + i;
364 dest->bdev = m->dev->bdev;
365 dest->sector = m->offset + dm_rh_region_to_sector(rh: ms->rh, region: key);
366 dest->count = from.count;
367 dest++;
368 }
369
370 /* hand to kcopyd */
371 if (!errors_handled(ms))
372 flags |= BIT(DM_KCOPYD_IGNORE_ERROR);
373
374 dm_kcopyd_copy(kc: ms->kcopyd_client, from: &from, num_dests: ms->nr_mirrors - 1, dests: to,
375 flags, fn: recovery_complete, context: reg);
376}
377
378static void reset_ms_flags(struct mirror_set *ms)
379{
380 unsigned int m;
381
382 ms->leg_failure = 0;
383 for (m = 0; m < ms->nr_mirrors; m++) {
384 atomic_set(v: &(ms->mirror[m].error_count), i: 0);
385 ms->mirror[m].error_type = 0;
386 }
387}
388
389static void do_recovery(struct mirror_set *ms)
390{
391 struct dm_region *reg;
392 struct dm_dirty_log *log = dm_rh_dirty_log(rh: ms->rh);
393
394 /*
395 * Start quiescing some regions.
396 */
397 dm_rh_recovery_prepare(rh: ms->rh);
398
399 /*
400 * Copy any already quiesced regions.
401 */
402 while ((reg = dm_rh_recovery_start(rh: ms->rh)))
403 recover(ms, reg);
404
405 /*
406 * Update the in sync flag.
407 */
408 if (!ms->in_sync &&
409 (log->type->get_sync_count(log) == ms->nr_regions)) {
410 /* the sync is complete */
411 dm_table_event(t: ms->ti->table);
412 ms->in_sync = 1;
413 reset_ms_flags(ms);
414 }
415}
416
417/*
418 *---------------------------------------------------------------
419 * Reads
420 *---------------------------------------------------------------
421 */
422static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
423{
424 struct mirror *m = get_default_mirror(ms);
425
426 do {
427 if (likely(!atomic_read(&m->error_count)))
428 return m;
429
430 if (m-- == ms->mirror)
431 m += ms->nr_mirrors;
432 } while (m != get_default_mirror(ms));
433
434 return NULL;
435}
436
437static int default_ok(struct mirror *m)
438{
439 struct mirror *default_mirror = get_default_mirror(ms: m->ms);
440
441 return !atomic_read(v: &default_mirror->error_count);
442}
443
444static int mirror_available(struct mirror_set *ms, struct bio *bio)
445{
446 struct dm_dirty_log *log = dm_rh_dirty_log(rh: ms->rh);
447 region_t region = dm_rh_bio_to_region(rh: ms->rh, bio);
448
449 if (log->type->in_sync(log, region, 0))
450 return choose_mirror(ms, sector: bio->bi_iter.bi_sector) ? 1 : 0;
451
452 return 0;
453}
454
455/*
456 * remap a buffer to a particular mirror.
457 */
458static sector_t map_sector(struct mirror *m, struct bio *bio)
459{
460 if (unlikely(!bio->bi_iter.bi_size))
461 return 0;
462 return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector);
463}
464
465static void map_bio(struct mirror *m, struct bio *bio)
466{
467 bio_set_dev(bio, bdev: m->dev->bdev);
468 bio->bi_iter.bi_sector = map_sector(m, bio);
469}
470
471static void map_region(struct dm_io_region *io, struct mirror *m,
472 struct bio *bio)
473{
474 io->bdev = m->dev->bdev;
475 io->sector = map_sector(m, bio);
476 io->count = bio_sectors(bio);
477}
478
479static void hold_bio(struct mirror_set *ms, struct bio *bio)
480{
481 /*
482 * Lock is required to avoid race condition during suspend
483 * process.
484 */
485 spin_lock_irq(lock: &ms->lock);
486
487 if (atomic_read(v: &ms->suspend)) {
488 spin_unlock_irq(lock: &ms->lock);
489
490 /*
491 * If device is suspended, complete the bio.
492 */
493 if (dm_noflush_suspending(ti: ms->ti))
494 bio->bi_status = BLK_STS_DM_REQUEUE;
495 else
496 bio->bi_status = BLK_STS_IOERR;
497
498 bio_endio(bio);
499 return;
500 }
501
502 /*
503 * Hold bio until the suspend is complete.
504 */
505 bio_list_add(bl: &ms->holds, bio);
506 spin_unlock_irq(lock: &ms->lock);
507}
508
509/*
510 *---------------------------------------------------------------
511 * Reads
512 *---------------------------------------------------------------
513 */
514static void read_callback(unsigned long error, void *context)
515{
516 struct bio *bio = context;
517 struct mirror *m;
518
519 m = bio_get_m(bio);
520 bio_set_m(bio, NULL);
521
522 if (likely(!error)) {
523 bio_endio(bio);
524 return;
525 }
526
527 fail_mirror(m, error_type: DM_RAID1_READ_ERROR);
528
529 if (likely(default_ok(m)) || mirror_available(ms: m->ms, bio)) {
530 DMWARN_LIMIT("Read failure on mirror device %s. Trying alternative device.",
531 m->dev->name);
532 queue_bio(ms: m->ms, bio, bio_data_dir(bio));
533 return;
534 }
535
536 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
537 m->dev->name);
538 bio_io_error(bio);
539}
540
541/* Asynchronous read. */
542static void read_async_bio(struct mirror *m, struct bio *bio)
543{
544 struct dm_io_region io;
545 struct dm_io_request io_req = {
546 .bi_opf = REQ_OP_READ,
547 .mem.type = DM_IO_BIO,
548 .mem.ptr.bio = bio,
549 .notify.fn = read_callback,
550 .notify.context = bio,
551 .client = m->ms->io_client,
552 };
553
554 map_region(io: &io, m, bio);
555 bio_set_m(bio, m);
556 BUG_ON(dm_io(&io_req, 1, &io, NULL, IOPRIO_DEFAULT));
557}
558
559static inline int region_in_sync(struct mirror_set *ms, region_t region,
560 int may_block)
561{
562 int state = dm_rh_get_state(rh: ms->rh, region, may_block);
563 return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
564}
565
566static void do_reads(struct mirror_set *ms, struct bio_list *reads)
567{
568 region_t region;
569 struct bio *bio;
570 struct mirror *m;
571
572 while ((bio = bio_list_pop(bl: reads))) {
573 region = dm_rh_bio_to_region(rh: ms->rh, bio);
574 m = get_default_mirror(ms);
575
576 /*
577 * We can only read balance if the region is in sync.
578 */
579 if (likely(region_in_sync(ms, region, 1)))
580 m = choose_mirror(ms, sector: bio->bi_iter.bi_sector);
581 else if (m && atomic_read(v: &m->error_count))
582 m = NULL;
583
584 if (likely(m))
585 read_async_bio(m, bio);
586 else
587 bio_io_error(bio);
588 }
589}
590
591/*
592 *---------------------------------------------------------------------
593 * Writes.
594 *
595 * We do different things with the write io depending on the
596 * state of the region that it's in:
597 *
598 * SYNC: increment pending, use kcopyd to write to *all* mirrors
599 * RECOVERING: delay the io until recovery completes
600 * NOSYNC: increment pending, just write to the default mirror
601 *---------------------------------------------------------------------
602 */
603static void write_callback(unsigned long error, void *context)
604{
605 unsigned int i;
606 struct bio *bio = context;
607 struct mirror_set *ms;
608 int should_wake = 0;
609 unsigned long flags;
610
611 ms = bio_get_m(bio)->ms;
612 bio_set_m(bio, NULL);
613
614 /*
615 * NOTE: We don't decrement the pending count here,
616 * instead it is done by the targets endio function.
617 * This way we handle both writes to SYNC and NOSYNC
618 * regions with the same code.
619 */
620 if (likely(!error)) {
621 bio_endio(bio);
622 return;
623 }
624
625 /*
626 * If the bio is discard, return an error, but do not
627 * degrade the array.
628 */
629 if (bio_op(bio) == REQ_OP_DISCARD) {
630 bio->bi_status = BLK_STS_NOTSUPP;
631 bio_endio(bio);
632 return;
633 }
634
635 for (i = 0; i < ms->nr_mirrors; i++)
636 if (test_bit(i, &error))
637 fail_mirror(m: ms->mirror + i, error_type: DM_RAID1_WRITE_ERROR);
638
639 /*
640 * Need to raise event. Since raising
641 * events can block, we need to do it in
642 * the main thread.
643 */
644 spin_lock_irqsave(&ms->lock, flags);
645 if (!ms->failures.head)
646 should_wake = 1;
647 bio_list_add(bl: &ms->failures, bio);
648 if (should_wake)
649 wakeup_mirrord(context: ms);
650 spin_unlock_irqrestore(lock: &ms->lock, flags);
651}
652
653static void do_write(struct mirror_set *ms, struct bio *bio)
654{
655 unsigned int i;
656 struct dm_io_region io[MAX_NR_MIRRORS], *dest = io;
657 struct mirror *m;
658 blk_opf_t op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH | REQ_ATOMIC);
659 struct dm_io_request io_req = {
660 .bi_opf = REQ_OP_WRITE | op_flags,
661 .mem.type = DM_IO_BIO,
662 .mem.ptr.bio = bio,
663 .notify.fn = write_callback,
664 .notify.context = bio,
665 .client = ms->io_client,
666 };
667
668 if (bio_op(bio) == REQ_OP_DISCARD) {
669 io_req.bi_opf = REQ_OP_DISCARD | op_flags;
670 io_req.mem.type = DM_IO_KMEM;
671 io_req.mem.ptr.addr = NULL;
672 }
673
674 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
675 map_region(io: dest++, m, bio);
676
677 /*
678 * Use default mirror because we only need it to retrieve the reference
679 * to the mirror set in write_callback().
680 */
681 bio_set_m(bio, m: get_default_mirror(ms));
682
683 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL, IOPRIO_DEFAULT));
684}
685
686static void do_writes(struct mirror_set *ms, struct bio_list *writes)
687{
688 int state;
689 struct bio *bio;
690 struct bio_list sync, nosync, recover, *this_list = NULL;
691 struct bio_list requeue;
692 struct dm_dirty_log *log = dm_rh_dirty_log(rh: ms->rh);
693 region_t region;
694
695 if (!writes->head)
696 return;
697
698 /*
699 * Classify each write.
700 */
701 bio_list_init(bl: &sync);
702 bio_list_init(bl: &nosync);
703 bio_list_init(bl: &recover);
704 bio_list_init(bl: &requeue);
705
706 while ((bio = bio_list_pop(bl: writes))) {
707 if ((bio->bi_opf & REQ_PREFLUSH) ||
708 (bio_op(bio) == REQ_OP_DISCARD)) {
709 bio_list_add(bl: &sync, bio);
710 continue;
711 }
712
713 region = dm_rh_bio_to_region(rh: ms->rh, bio);
714
715 if (log->type->is_remote_recovering &&
716 log->type->is_remote_recovering(log, region)) {
717 bio_list_add(bl: &requeue, bio);
718 continue;
719 }
720
721 state = dm_rh_get_state(rh: ms->rh, region, may_block: 1);
722 switch (state) {
723 case DM_RH_CLEAN:
724 case DM_RH_DIRTY:
725 this_list = &sync;
726 break;
727
728 case DM_RH_NOSYNC:
729 this_list = &nosync;
730 break;
731
732 case DM_RH_RECOVERING:
733 this_list = &recover;
734 break;
735 }
736
737 bio_list_add(bl: this_list, bio);
738 }
739
740 /*
741 * Add bios that are delayed due to remote recovery
742 * back on to the write queue
743 */
744 if (unlikely(requeue.head)) {
745 spin_lock_irq(lock: &ms->lock);
746 bio_list_merge(bl: &ms->writes, bl2: &requeue);
747 spin_unlock_irq(lock: &ms->lock);
748 delayed_wake(ms);
749 }
750
751 /*
752 * Increment the pending counts for any regions that will
753 * be written to (writes to recover regions are going to
754 * be delayed).
755 */
756 dm_rh_inc_pending(rh: ms->rh, bios: &sync);
757 dm_rh_inc_pending(rh: ms->rh, bios: &nosync);
758
759 /*
760 * If the flush fails on a previous call and succeeds here,
761 * we must not reset the log_failure variable. We need
762 * userspace interaction to do that.
763 */
764 ms->log_failure = dm_rh_flush(rh: ms->rh) ? 1 : ms->log_failure;
765
766 /*
767 * Dispatch io.
768 */
769 if (unlikely(ms->log_failure) && errors_handled(ms)) {
770 spin_lock_irq(lock: &ms->lock);
771 bio_list_merge(bl: &ms->failures, bl2: &sync);
772 spin_unlock_irq(lock: &ms->lock);
773 wakeup_mirrord(context: ms);
774 } else
775 while ((bio = bio_list_pop(bl: &sync)))
776 do_write(ms, bio);
777
778 while ((bio = bio_list_pop(bl: &recover)))
779 dm_rh_delay(rh: ms->rh, bio);
780
781 while ((bio = bio_list_pop(bl: &nosync))) {
782 if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) {
783 spin_lock_irq(lock: &ms->lock);
784 bio_list_add(bl: &ms->failures, bio);
785 spin_unlock_irq(lock: &ms->lock);
786 wakeup_mirrord(context: ms);
787 } else {
788 map_bio(m: get_default_mirror(ms), bio);
789 submit_bio_noacct(bio);
790 }
791 }
792}
793
794static void do_failures(struct mirror_set *ms, struct bio_list *failures)
795{
796 struct bio *bio;
797
798 if (likely(!failures->head))
799 return;
800
801 /*
802 * If the log has failed, unattempted writes are being
803 * put on the holds list. We can't issue those writes
804 * until a log has been marked, so we must store them.
805 *
806 * If a 'noflush' suspend is in progress, we can requeue
807 * the I/O's to the core. This give userspace a chance
808 * to reconfigure the mirror, at which point the core
809 * will reissue the writes. If the 'noflush' flag is
810 * not set, we have no choice but to return errors.
811 *
812 * Some writes on the failures list may have been
813 * submitted before the log failure and represent a
814 * failure to write to one of the devices. It is ok
815 * for us to treat them the same and requeue them
816 * as well.
817 */
818 while ((bio = bio_list_pop(bl: failures))) {
819 if (!ms->log_failure) {
820 ms->in_sync = 0;
821 dm_rh_mark_nosync(rh: ms->rh, bio);
822 }
823
824 /*
825 * If all the legs are dead, fail the I/O.
826 * If the device has failed and keep_log is enabled,
827 * fail the I/O.
828 *
829 * If we have been told to handle errors, and keep_log
830 * isn't enabled, hold the bio and wait for userspace to
831 * deal with the problem.
832 *
833 * Otherwise pretend that the I/O succeeded. (This would
834 * be wrong if the failed leg returned after reboot and
835 * got replicated back to the good legs.)
836 */
837 if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure)))
838 bio_io_error(bio);
839 else if (errors_handled(ms) && !keep_log(ms))
840 hold_bio(ms, bio);
841 else
842 bio_endio(bio);
843 }
844}
845
846static void trigger_event(struct work_struct *work)
847{
848 struct mirror_set *ms =
849 container_of(work, struct mirror_set, trigger_event);
850
851 dm_table_event(t: ms->ti->table);
852}
853
854/*
855 *---------------------------------------------------------------
856 * kmirrord
857 *---------------------------------------------------------------
858 */
859static void do_mirror(struct work_struct *work)
860{
861 struct mirror_set *ms = container_of(work, struct mirror_set,
862 kmirrord_work);
863 struct bio_list reads, writes, failures;
864 unsigned long flags;
865
866 spin_lock_irqsave(&ms->lock, flags);
867 reads = ms->reads;
868 writes = ms->writes;
869 failures = ms->failures;
870 bio_list_init(bl: &ms->reads);
871 bio_list_init(bl: &ms->writes);
872 bio_list_init(bl: &ms->failures);
873 spin_unlock_irqrestore(lock: &ms->lock, flags);
874
875 dm_rh_update_states(rh: ms->rh, errors_handled(ms));
876 do_recovery(ms);
877 do_reads(ms, reads: &reads);
878 do_writes(ms, writes: &writes);
879 do_failures(ms, failures: &failures);
880}
881
882/*
883 *---------------------------------------------------------------
884 * Target functions
885 *---------------------------------------------------------------
886 */
887static struct mirror_set *alloc_context(unsigned int nr_mirrors,
888 uint32_t region_size,
889 struct dm_target *ti,
890 struct dm_dirty_log *dl)
891{
892 struct mirror_set *ms =
893 kzalloc(struct_size(ms, mirror, nr_mirrors), GFP_KERNEL);
894
895 if (!ms) {
896 ti->error = "Cannot allocate mirror context";
897 return NULL;
898 }
899
900 spin_lock_init(&ms->lock);
901 bio_list_init(bl: &ms->reads);
902 bio_list_init(bl: &ms->writes);
903 bio_list_init(bl: &ms->failures);
904 bio_list_init(bl: &ms->holds);
905
906 ms->ti = ti;
907 ms->nr_mirrors = nr_mirrors;
908 ms->nr_regions = dm_sector_div_up(ti->len, region_size);
909 ms->in_sync = 0;
910 ms->log_failure = 0;
911 ms->leg_failure = 0;
912 atomic_set(v: &ms->suspend, i: 0);
913 atomic_set(v: &ms->default_mirror, DEFAULT_MIRROR);
914
915 ms->io_client = dm_io_client_create();
916 if (IS_ERR(ptr: ms->io_client)) {
917 ti->error = "Error creating dm_io client";
918 kfree(objp: ms);
919 return NULL;
920 }
921
922 ms->rh = dm_region_hash_create(context: ms, dispatch_bios, wakeup_workers: wakeup_mirrord,
923 wakeup_all_recovery_waiters,
924 target_begin: ms->ti->begin, MAX_RECOVERY,
925 log: dl, region_size, nr_regions: ms->nr_regions);
926 if (IS_ERR(ptr: ms->rh)) {
927 ti->error = "Error creating dirty region hash";
928 dm_io_client_destroy(client: ms->io_client);
929 kfree(objp: ms);
930 return NULL;
931 }
932
933 return ms;
934}
935
936static void free_context(struct mirror_set *ms, struct dm_target *ti,
937 unsigned int m)
938{
939 while (m--)
940 dm_put_device(ti, d: ms->mirror[m].dev);
941
942 dm_io_client_destroy(client: ms->io_client);
943 dm_region_hash_destroy(rh: ms->rh);
944 kfree(objp: ms);
945}
946
947static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
948 unsigned int mirror, char **argv)
949{
950 unsigned long long offset;
951 char dummy;
952 int ret;
953
954 if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1 ||
955 offset != (sector_t)offset) {
956 ti->error = "Invalid offset";
957 return -EINVAL;
958 }
959
960 ret = dm_get_device(ti, path: argv[0], mode: dm_table_get_mode(t: ti->table),
961 result: &ms->mirror[mirror].dev);
962 if (ret) {
963 ti->error = "Device lookup failure";
964 return ret;
965 }
966
967 ms->mirror[mirror].ms = ms;
968 atomic_set(v: &(ms->mirror[mirror].error_count), i: 0);
969 ms->mirror[mirror].error_type = 0;
970 ms->mirror[mirror].offset = offset;
971
972 return 0;
973}
974
975/*
976 * Create dirty log: log_type #log_params <log_params>
977 */
978static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
979 unsigned int argc, char **argv,
980 unsigned int *args_used)
981{
982 unsigned int param_count;
983 struct dm_dirty_log *dl;
984 char dummy;
985
986 if (argc < 2) {
987 ti->error = "Insufficient mirror log arguments";
988 return NULL;
989 }
990
991 if (sscanf(argv[1], "%u%c", &param_count, &dummy) != 1) {
992 ti->error = "Invalid mirror log argument count";
993 return NULL;
994 }
995
996 *args_used = 2 + param_count;
997
998 if (argc < *args_used) {
999 ti->error = "Insufficient mirror log arguments";
1000 return NULL;
1001 }
1002
1003 dl = dm_dirty_log_create(type_name: argv[0], ti, flush_callback_fn: mirror_flush, argc: param_count,
1004 argv: argv + 2);
1005 if (!dl) {
1006 ti->error = "Error creating mirror dirty log";
1007 return NULL;
1008 }
1009
1010 return dl;
1011}
1012
1013static int parse_features(struct mirror_set *ms, unsigned int argc, char **argv,
1014 unsigned int *args_used)
1015{
1016 unsigned int num_features;
1017 struct dm_target *ti = ms->ti;
1018 char dummy;
1019 int i;
1020
1021 *args_used = 0;
1022
1023 if (!argc)
1024 return 0;
1025
1026 if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) {
1027 ti->error = "Invalid number of features";
1028 return -EINVAL;
1029 }
1030
1031 argc--;
1032 argv++;
1033 (*args_used)++;
1034
1035 if (num_features > argc) {
1036 ti->error = "Not enough arguments to support feature count";
1037 return -EINVAL;
1038 }
1039
1040 for (i = 0; i < num_features; i++) {
1041 if (!strcmp("handle_errors", argv[0]))
1042 ms->features |= DM_RAID1_HANDLE_ERRORS;
1043 else if (!strcmp("keep_log", argv[0]))
1044 ms->features |= DM_RAID1_KEEP_LOG;
1045 else {
1046 ti->error = "Unrecognised feature requested";
1047 return -EINVAL;
1048 }
1049
1050 argc--;
1051 argv++;
1052 (*args_used)++;
1053 }
1054 if (!errors_handled(ms) && keep_log(ms)) {
1055 ti->error = "keep_log feature requires the handle_errors feature";
1056 return -EINVAL;
1057 }
1058
1059 return 0;
1060}
1061
1062/*
1063 * Construct a mirror mapping:
1064 *
1065 * log_type #log_params <log_params>
1066 * #mirrors [mirror_path offset]{2,}
1067 * [#features <features>]
1068 *
1069 * log_type is "core" or "disk"
1070 * #log_params is between 1 and 3
1071 *
1072 * If present, supported features are "handle_errors" and "keep_log".
1073 */
1074static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1075{
1076 int r;
1077 unsigned int nr_mirrors, m, args_used;
1078 struct mirror_set *ms;
1079 struct dm_dirty_log *dl;
1080 char dummy;
1081
1082 dl = create_dirty_log(ti, argc, argv, args_used: &args_used);
1083 if (!dl)
1084 return -EINVAL;
1085
1086 argv += args_used;
1087 argc -= args_used;
1088
1089 if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
1090 nr_mirrors < 2 || nr_mirrors > MAX_NR_MIRRORS) {
1091 ti->error = "Invalid number of mirrors";
1092 dm_dirty_log_destroy(log: dl);
1093 return -EINVAL;
1094 }
1095
1096 argv++, argc--;
1097
1098 if (argc < nr_mirrors * 2) {
1099 ti->error = "Too few mirror arguments";
1100 dm_dirty_log_destroy(log: dl);
1101 return -EINVAL;
1102 }
1103
1104 ms = alloc_context(nr_mirrors, region_size: dl->type->get_region_size(dl), ti, dl);
1105 if (!ms) {
1106 dm_dirty_log_destroy(log: dl);
1107 return -ENOMEM;
1108 }
1109
1110 /* Get the mirror parameter sets */
1111 for (m = 0; m < nr_mirrors; m++) {
1112 r = get_mirror(ms, ti, mirror: m, argv);
1113 if (r) {
1114 free_context(ms, ti, m);
1115 return r;
1116 }
1117 argv += 2;
1118 argc -= 2;
1119 }
1120
1121 ti->private = ms;
1122
1123 r = dm_set_target_max_io_len(ti, len: dm_rh_get_region_size(rh: ms->rh));
1124 if (r)
1125 goto err_free_context;
1126
1127 ti->num_flush_bios = 1;
1128 ti->num_discard_bios = 1;
1129 ti->per_io_data_size = sizeof(struct dm_raid1_bio_record);
1130
1131 ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0);
1132 if (!ms->kmirrord_wq) {
1133 DMERR("couldn't start kmirrord");
1134 r = -ENOMEM;
1135 goto err_free_context;
1136 }
1137 INIT_WORK(&ms->kmirrord_work, do_mirror);
1138 timer_setup(&ms->timer, delayed_wake_fn, 0);
1139 ms->timer_pending = 0;
1140 INIT_WORK(&ms->trigger_event, trigger_event);
1141
1142 r = parse_features(ms, argc, argv, args_used: &args_used);
1143 if (r)
1144 goto err_destroy_wq;
1145
1146 argv += args_used;
1147 argc -= args_used;
1148
1149 /*
1150 * Any read-balancing addition depends on the
1151 * DM_RAID1_HANDLE_ERRORS flag being present.
1152 * This is because the decision to balance depends
1153 * on the sync state of a region. If the above
1154 * flag is not present, we ignore errors; and
1155 * the sync state may be inaccurate.
1156 */
1157
1158 if (argc) {
1159 ti->error = "Too many mirror arguments";
1160 r = -EINVAL;
1161 goto err_destroy_wq;
1162 }
1163
1164 ms->kcopyd_client = dm_kcopyd_client_create(throttle: &dm_kcopyd_throttle);
1165 if (IS_ERR(ptr: ms->kcopyd_client)) {
1166 r = PTR_ERR(ptr: ms->kcopyd_client);
1167 goto err_destroy_wq;
1168 }
1169
1170 wakeup_mirrord(context: ms);
1171 return 0;
1172
1173err_destroy_wq:
1174 destroy_workqueue(wq: ms->kmirrord_wq);
1175err_free_context:
1176 free_context(ms, ti, m: ms->nr_mirrors);
1177 return r;
1178}
1179
1180static void mirror_dtr(struct dm_target *ti)
1181{
1182 struct mirror_set *ms = ti->private;
1183
1184 timer_delete_sync(timer: &ms->timer);
1185 flush_workqueue(ms->kmirrord_wq);
1186 flush_work(work: &ms->trigger_event);
1187 dm_kcopyd_client_destroy(kc: ms->kcopyd_client);
1188 destroy_workqueue(wq: ms->kmirrord_wq);
1189 free_context(ms, ti, m: ms->nr_mirrors);
1190}
1191
1192/*
1193 * Mirror mapping function
1194 */
1195static int mirror_map(struct dm_target *ti, struct bio *bio)
1196{
1197 int r, rw = bio_data_dir(bio);
1198 struct mirror *m;
1199 struct mirror_set *ms = ti->private;
1200 struct dm_dirty_log *log = dm_rh_dirty_log(rh: ms->rh);
1201 struct dm_raid1_bio_record *bio_record =
1202 dm_per_bio_data(bio, data_size: sizeof(struct dm_raid1_bio_record));
1203
1204 bio_record->details.bi_bdev = NULL;
1205
1206 if (rw == WRITE) {
1207 /* Save region for mirror_end_io() handler */
1208 bio_record->write_region = dm_rh_bio_to_region(rh: ms->rh, bio);
1209 queue_bio(ms, bio, rw);
1210 return DM_MAPIO_SUBMITTED;
1211 }
1212
1213 r = log->type->in_sync(log, dm_rh_bio_to_region(rh: ms->rh, bio), 0);
1214 if (r < 0 && r != -EWOULDBLOCK)
1215 return DM_MAPIO_KILL;
1216
1217 /*
1218 * If region is not in-sync queue the bio.
1219 */
1220 if (!r || (r == -EWOULDBLOCK)) {
1221 if (bio->bi_opf & REQ_RAHEAD)
1222 return DM_MAPIO_KILL;
1223
1224 queue_bio(ms, bio, rw);
1225 return DM_MAPIO_SUBMITTED;
1226 }
1227
1228 /*
1229 * The region is in-sync and we can perform reads directly.
1230 * Store enough information so we can retry if it fails.
1231 */
1232 m = choose_mirror(ms, sector: bio->bi_iter.bi_sector);
1233 if (unlikely(!m))
1234 return DM_MAPIO_KILL;
1235
1236 dm_bio_record(bd: &bio_record->details, bio);
1237 bio_record->m = m;
1238
1239 map_bio(m, bio);
1240
1241 return DM_MAPIO_REMAPPED;
1242}
1243
1244static int mirror_end_io(struct dm_target *ti, struct bio *bio,
1245 blk_status_t *error)
1246{
1247 int rw = bio_data_dir(bio);
1248 struct mirror_set *ms = ti->private;
1249 struct mirror *m = NULL;
1250 struct dm_bio_details *bd = NULL;
1251 struct dm_raid1_bio_record *bio_record =
1252 dm_per_bio_data(bio, data_size: sizeof(struct dm_raid1_bio_record));
1253
1254 /*
1255 * We need to dec pending if this was a write.
1256 */
1257 if (rw == WRITE) {
1258 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1259 bio_op(bio) != REQ_OP_DISCARD)
1260 dm_rh_dec(rh: ms->rh, region: bio_record->write_region);
1261 return DM_ENDIO_DONE;
1262 }
1263
1264 if (*error == BLK_STS_NOTSUPP)
1265 goto out;
1266
1267 if (bio->bi_opf & REQ_RAHEAD)
1268 goto out;
1269
1270 if (unlikely(*error)) {
1271 if (!bio_record->details.bi_bdev) {
1272 /*
1273 * There wasn't enough memory to record necessary
1274 * information for a retry or there was no other
1275 * mirror in-sync.
1276 */
1277 DMERR_LIMIT("Mirror read failed.");
1278 return DM_ENDIO_DONE;
1279 }
1280
1281 m = bio_record->m;
1282
1283 DMERR("Mirror read failed from %s. Trying alternative device.",
1284 m->dev->name);
1285
1286 fail_mirror(m, error_type: DM_RAID1_READ_ERROR);
1287
1288 /*
1289 * A failed read is requeued for another attempt using an intact
1290 * mirror.
1291 */
1292 if (default_ok(m) || mirror_available(ms, bio)) {
1293 bd = &bio_record->details;
1294
1295 dm_bio_restore(bd, bio);
1296 bio_record->details.bi_bdev = NULL;
1297 bio->bi_status = 0;
1298
1299 queue_bio(ms, bio, rw);
1300 return DM_ENDIO_INCOMPLETE;
1301 }
1302 DMERR("All replicated volumes dead, failing I/O");
1303 }
1304
1305out:
1306 bio_record->details.bi_bdev = NULL;
1307
1308 return DM_ENDIO_DONE;
1309}
1310
1311static void mirror_presuspend(struct dm_target *ti)
1312{
1313 struct mirror_set *ms = ti->private;
1314 struct dm_dirty_log *log = dm_rh_dirty_log(rh: ms->rh);
1315
1316 struct bio_list holds;
1317 struct bio *bio;
1318
1319 atomic_set(v: &ms->suspend, i: 1);
1320
1321 /*
1322 * Process bios in the hold list to start recovery waiting
1323 * for bios in the hold list. After the process, no bio has
1324 * a chance to be added in the hold list because ms->suspend
1325 * is set.
1326 */
1327 spin_lock_irq(lock: &ms->lock);
1328 holds = ms->holds;
1329 bio_list_init(bl: &ms->holds);
1330 spin_unlock_irq(lock: &ms->lock);
1331
1332 while ((bio = bio_list_pop(bl: &holds)))
1333 hold_bio(ms, bio);
1334
1335 /*
1336 * We must finish up all the work that we've
1337 * generated (i.e. recovery work).
1338 */
1339 dm_rh_stop_recovery(rh: ms->rh);
1340
1341 wait_event(_kmirrord_recovery_stopped,
1342 !dm_rh_recovery_in_flight(ms->rh));
1343
1344 if (log->type->presuspend && log->type->presuspend(log))
1345 /* FIXME: need better error handling */
1346 DMWARN("log presuspend failed");
1347
1348 /*
1349 * Now that recovery is complete/stopped and the
1350 * delayed bios are queued, we need to wait for
1351 * the worker thread to complete. This way,
1352 * we know that all of our I/O has been pushed.
1353 */
1354 flush_workqueue(ms->kmirrord_wq);
1355}
1356
1357static void mirror_postsuspend(struct dm_target *ti)
1358{
1359 struct mirror_set *ms = ti->private;
1360 struct dm_dirty_log *log = dm_rh_dirty_log(rh: ms->rh);
1361
1362 if (log->type->postsuspend && log->type->postsuspend(log))
1363 /* FIXME: need better error handling */
1364 DMWARN("log postsuspend failed");
1365}
1366
1367static void mirror_resume(struct dm_target *ti)
1368{
1369 struct mirror_set *ms = ti->private;
1370 struct dm_dirty_log *log = dm_rh_dirty_log(rh: ms->rh);
1371
1372 atomic_set(v: &ms->suspend, i: 0);
1373 if (log->type->resume && log->type->resume(log))
1374 /* FIXME: need better error handling */
1375 DMWARN("log resume failed");
1376 dm_rh_start_recovery(rh: ms->rh);
1377}
1378
1379/*
1380 * device_status_char
1381 * @m: mirror device/leg we want the status of
1382 *
1383 * We return one character representing the most severe error
1384 * we have encountered.
1385 * A => Alive - No failures
1386 * D => Dead - A write failure occurred leaving mirror out-of-sync
1387 * S => Sync - A sychronization failure occurred, mirror out-of-sync
1388 * R => Read - A read failure occurred, mirror data unaffected
1389 *
1390 * Returns: <char>
1391 */
1392static char device_status_char(struct mirror *m)
1393{
1394 if (!atomic_read(v: &(m->error_count)))
1395 return 'A';
1396
1397 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
1398 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
1399 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
1400 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
1401}
1402
1403
1404static void mirror_status(struct dm_target *ti, status_type_t type,
1405 unsigned int status_flags, char *result, unsigned int maxlen)
1406{
1407 unsigned int m, sz = 0;
1408 int num_feature_args = 0;
1409 struct mirror_set *ms = ti->private;
1410 struct dm_dirty_log *log = dm_rh_dirty_log(rh: ms->rh);
1411 char buffer[MAX_NR_MIRRORS + 1];
1412
1413 switch (type) {
1414 case STATUSTYPE_INFO:
1415 DMEMIT("%d ", ms->nr_mirrors);
1416 for (m = 0; m < ms->nr_mirrors; m++) {
1417 DMEMIT("%s ", ms->mirror[m].dev->name);
1418 buffer[m] = device_status_char(m: &(ms->mirror[m]));
1419 }
1420 buffer[m] = '\0';
1421
1422 DMEMIT("%llu/%llu 1 %s ",
1423 (unsigned long long)log->type->get_sync_count(log),
1424 (unsigned long long)ms->nr_regions, buffer);
1425
1426 sz += log->type->status(log, type, result+sz, maxlen-sz);
1427
1428 break;
1429
1430 case STATUSTYPE_TABLE:
1431 sz = log->type->status(log, type, result, maxlen);
1432
1433 DMEMIT("%d", ms->nr_mirrors);
1434 for (m = 0; m < ms->nr_mirrors; m++)
1435 DMEMIT(" %s %llu", ms->mirror[m].dev->name,
1436 (unsigned long long)ms->mirror[m].offset);
1437
1438 num_feature_args += !!errors_handled(ms);
1439 num_feature_args += !!keep_log(ms);
1440 if (num_feature_args) {
1441 DMEMIT(" %d", num_feature_args);
1442 if (errors_handled(ms))
1443 DMEMIT(" handle_errors");
1444 if (keep_log(ms))
1445 DMEMIT(" keep_log");
1446 }
1447
1448 break;
1449
1450 case STATUSTYPE_IMA:
1451 DMEMIT_TARGET_NAME_VERSION(ti->type);
1452 DMEMIT(",nr_mirrors=%d", ms->nr_mirrors);
1453 for (m = 0; m < ms->nr_mirrors; m++) {
1454 DMEMIT(",mirror_device_%d=%s", m, ms->mirror[m].dev->name);
1455 DMEMIT(",mirror_device_%d_status=%c",
1456 m, device_status_char(&(ms->mirror[m])));
1457 }
1458
1459 DMEMIT(",handle_errors=%c", errors_handled(ms) ? 'y' : 'n');
1460 DMEMIT(",keep_log=%c", keep_log(ms) ? 'y' : 'n');
1461
1462 DMEMIT(",log_type_status=");
1463 sz += log->type->status(log, type, result+sz, maxlen-sz);
1464 DMEMIT(";");
1465 break;
1466 }
1467}
1468
1469static int mirror_iterate_devices(struct dm_target *ti,
1470 iterate_devices_callout_fn fn, void *data)
1471{
1472 struct mirror_set *ms = ti->private;
1473 int ret = 0;
1474 unsigned int i;
1475
1476 for (i = 0; !ret && i < ms->nr_mirrors; i++)
1477 ret = fn(ti, ms->mirror[i].dev,
1478 ms->mirror[i].offset, ti->len, data);
1479
1480 return ret;
1481}
1482
1483static struct target_type mirror_target = {
1484 .name = "mirror",
1485 .version = {1, 15, 0},
1486 .module = THIS_MODULE,
1487 .features = DM_TARGET_ATOMIC_WRITES,
1488 .ctr = mirror_ctr,
1489 .dtr = mirror_dtr,
1490 .map = mirror_map,
1491 .end_io = mirror_end_io,
1492 .presuspend = mirror_presuspend,
1493 .postsuspend = mirror_postsuspend,
1494 .resume = mirror_resume,
1495 .status = mirror_status,
1496 .iterate_devices = mirror_iterate_devices,
1497};
1498
1499static int __init dm_mirror_init(void)
1500{
1501 int r;
1502
1503 dm_raid1_wq = alloc_workqueue("dm_raid1_wq", 0, 0);
1504 if (!dm_raid1_wq) {
1505 DMERR("Failed to alloc workqueue");
1506 return -ENOMEM;
1507 }
1508
1509 r = dm_register_target(t: &mirror_target);
1510 if (r < 0) {
1511 destroy_workqueue(wq: dm_raid1_wq);
1512 return r;
1513 }
1514
1515 return 0;
1516}
1517
1518static void __exit dm_mirror_exit(void)
1519{
1520 destroy_workqueue(wq: dm_raid1_wq);
1521 dm_unregister_target(t: &mirror_target);
1522}
1523
1524/* Module hooks */
1525module_init(dm_mirror_init);
1526module_exit(dm_mirror_exit);
1527
1528MODULE_DESCRIPTION(DM_NAME " mirror target");
1529MODULE_AUTHOR("Joe Thornber");
1530MODULE_LICENSE("GPL");
1531