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1/*
2 * Copyright (C) 2003 Sistina Software Limited.
3 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-bio-record.h"
9
10#include <linux/init.h>
11#include <linux/mempool.h>
12#include <linux/module.h>
13#include <linux/pagemap.h>
14#include <linux/slab.h>
15#include <linux/workqueue.h>
16#include <linux/device-mapper.h>
17#include <linux/dm-io.h>
18#include <linux/dm-dirty-log.h>
19#include <linux/dm-kcopyd.h>
20#include <linux/dm-region-hash.h>
21
22#define DM_MSG_PREFIX "raid1"
23
24#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
25
26#define DM_RAID1_HANDLE_ERRORS 0x01
27#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
28
29static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
30
31/*-----------------------------------------------------------------
32 * Mirror set structures.
33 *---------------------------------------------------------------*/
34enum dm_raid1_error {
35 DM_RAID1_WRITE_ERROR,
36 DM_RAID1_FLUSH_ERROR,
37 DM_RAID1_SYNC_ERROR,
38 DM_RAID1_READ_ERROR
39};
40
41struct mirror {
42 struct mirror_set *ms;
43 atomic_t error_count;
44 unsigned long error_type;
45 struct dm_dev *dev;
46 sector_t offset;
47};
48
49struct mirror_set {
50 struct dm_target *ti;
51 struct list_head list;
52
53 uint64_t features;
54
55 spinlock_t lock; /* protects the lists */
56 struct bio_list reads;
57 struct bio_list writes;
58 struct bio_list failures;
59 struct bio_list holds; /* bios are waiting until suspend */
60
61 struct dm_region_hash *rh;
62 struct dm_kcopyd_client *kcopyd_client;
63 struct dm_io_client *io_client;
64 mempool_t *read_record_pool;
65
66 /* recovery */
67 region_t nr_regions;
68 int in_sync;
69 int log_failure;
70 int leg_failure;
71 atomic_t suspend;
72
73 atomic_t default_mirror; /* Default mirror */
74
75 struct workqueue_struct *kmirrord_wq;
76 struct work_struct kmirrord_work;
77 struct timer_list timer;
78 unsigned long timer_pending;
79
80 struct work_struct trigger_event;
81
82 unsigned nr_mirrors;
83 struct mirror mirror[0];
84};
85
86static void wakeup_mirrord(void *context)
87{
88 struct mirror_set *ms = context;
89
90 queue_work(ms->kmirrord_wq, &ms->kmirrord_work);
91}
92
93static void delayed_wake_fn(unsigned long data)
94{
95 struct mirror_set *ms = (struct mirror_set *) data;
96
97 clear_bit(0, &ms->timer_pending);
98 wakeup_mirrord(ms);
99}
100
101static void delayed_wake(struct mirror_set *ms)
102{
103 if (test_and_set_bit(0, &ms->timer_pending))
104 return;
105
106 ms->timer.expires = jiffies + HZ / 5;
107 ms->timer.data = (unsigned long) ms;
108 ms->timer.function = delayed_wake_fn;
109 add_timer(&ms->timer);
110}
111
112static void wakeup_all_recovery_waiters(void *context)
113{
114 wake_up_all(&_kmirrord_recovery_stopped);
115}
116
117static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
118{
119 unsigned long flags;
120 int should_wake = 0;
121 struct bio_list *bl;
122
123 bl = (rw == WRITE) ? &ms->writes : &ms->reads;
124 spin_lock_irqsave(&ms->lock, flags);
125 should_wake = !(bl->head);
126 bio_list_add(bl, bio);
127 spin_unlock_irqrestore(&ms->lock, flags);
128
129 if (should_wake)
130 wakeup_mirrord(ms);
131}
132
133static void dispatch_bios(void *context, struct bio_list *bio_list)
134{
135 struct mirror_set *ms = context;
136 struct bio *bio;
137
138 while ((bio = bio_list_pop(bio_list)))
139 queue_bio(ms, bio, WRITE);
140}
141
142#define MIN_READ_RECORDS 20
143struct dm_raid1_read_record {
144 struct mirror *m;
145 struct dm_bio_details details;
146};
147
148static struct kmem_cache *_dm_raid1_read_record_cache;
149
150/*
151 * Every mirror should look like this one.
152 */
153#define DEFAULT_MIRROR 0
154
155/*
156 * This is yucky. We squirrel the mirror struct away inside
157 * bi_next for read/write buffers. This is safe since the bh
158 * doesn't get submitted to the lower levels of block layer.
159 */
160static struct mirror *bio_get_m(struct bio *bio)
161{
162 return (struct mirror *) bio->bi_next;
163}
164
165static void bio_set_m(struct bio *bio, struct mirror *m)
166{
167 bio->bi_next = (struct bio *) m;
168}
169
170static struct mirror *get_default_mirror(struct mirror_set *ms)
171{
172 return &ms->mirror[atomic_read(&ms->default_mirror)];
173}
174
175static void set_default_mirror(struct mirror *m)
176{
177 struct mirror_set *ms = m->ms;
178 struct mirror *m0 = &(ms->mirror[0]);
179
180 atomic_set(&ms->default_mirror, m - m0);
181}
182
183static struct mirror *get_valid_mirror(struct mirror_set *ms)
184{
185 struct mirror *m;
186
187 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
188 if (!atomic_read(&m->error_count))
189 return m;
190
191 return NULL;
192}
193
194/* fail_mirror
195 * @m: mirror device to fail
196 * @error_type: one of the enum's, DM_RAID1_*_ERROR
197 *
198 * If errors are being handled, record the type of
199 * error encountered for this device. If this type
200 * of error has already been recorded, we can return;
201 * otherwise, we must signal userspace by triggering
202 * an event. Additionally, if the device is the
203 * primary device, we must choose a new primary, but
204 * only if the mirror is in-sync.
205 *
206 * This function must not block.
207 */
208static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
209{
210 struct mirror_set *ms = m->ms;
211 struct mirror *new;
212
213 ms->leg_failure = 1;
214
215 /*
216 * error_count is used for nothing more than a
217 * simple way to tell if a device has encountered
218 * errors.
219 */
220 atomic_inc(&m->error_count);
221
222 if (test_and_set_bit(error_type, &m->error_type))
223 return;
224
225 if (!errors_handled(ms))
226 return;
227
228 if (m != get_default_mirror(ms))
229 goto out;
230
231 if (!ms->in_sync) {
232 /*
233 * Better to issue requests to same failing device
234 * than to risk returning corrupt data.
235 */
236 DMERR("Primary mirror (%s) failed while out-of-sync: "
237 "Reads may fail.", m->dev->name);
238 goto out;
239 }
240
241 new = get_valid_mirror(ms);
242 if (new)
243 set_default_mirror(new);
244 else
245 DMWARN("All sides of mirror have failed.");
246
247out:
248 schedule_work(&ms->trigger_event);
249}
250
251static int mirror_flush(struct dm_target *ti)
252{
253 struct mirror_set *ms = ti->private;
254 unsigned long error_bits;
255
256 unsigned int i;
257 struct dm_io_region io[ms->nr_mirrors];
258 struct mirror *m;
259 struct dm_io_request io_req = {
260 .bi_rw = WRITE_FLUSH,
261 .mem.type = DM_IO_KMEM,
262 .mem.ptr.addr = NULL,
263 .client = ms->io_client,
264 };
265
266 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
267 io[i].bdev = m->dev->bdev;
268 io[i].sector = 0;
269 io[i].count = 0;
270 }
271
272 error_bits = -1;
273 dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
274 if (unlikely(error_bits != 0)) {
275 for (i = 0; i < ms->nr_mirrors; i++)
276 if (test_bit(i, &error_bits))
277 fail_mirror(ms->mirror + i,
278 DM_RAID1_FLUSH_ERROR);
279 return -EIO;
280 }
281
282 return 0;
283}
284
285/*-----------------------------------------------------------------
286 * Recovery.
287 *
288 * When a mirror is first activated we may find that some regions
289 * are in the no-sync state. We have to recover these by
290 * recopying from the default mirror to all the others.
291 *---------------------------------------------------------------*/
292static void recovery_complete(int read_err, unsigned long write_err,
293 void *context)
294{
295 struct dm_region *reg = context;
296 struct mirror_set *ms = dm_rh_region_context(reg);
297 int m, bit = 0;
298
299 if (read_err) {
300 /* Read error means the failure of default mirror. */
301 DMERR_LIMIT("Unable to read primary mirror during recovery");
302 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR);
303 }
304
305 if (write_err) {
306 DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
307 write_err);
308 /*
309 * Bits correspond to devices (excluding default mirror).
310 * The default mirror cannot change during recovery.
311 */
312 for (m = 0; m < ms->nr_mirrors; m++) {
313 if (&ms->mirror[m] == get_default_mirror(ms))
314 continue;
315 if (test_bit(bit, &write_err))
316 fail_mirror(ms->mirror + m,
317 DM_RAID1_SYNC_ERROR);
318 bit++;
319 }
320 }
321
322 dm_rh_recovery_end(reg, !(read_err || write_err));
323}
324
325static int recover(struct mirror_set *ms, struct dm_region *reg)
326{
327 int r;
328 unsigned i;
329 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
330 struct mirror *m;
331 unsigned long flags = 0;
332 region_t key = dm_rh_get_region_key(reg);
333 sector_t region_size = dm_rh_get_region_size(ms->rh);
334
335 /* fill in the source */
336 m = get_default_mirror(ms);
337 from.bdev = m->dev->bdev;
338 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
339 if (key == (ms->nr_regions - 1)) {
340 /*
341 * The final region may be smaller than
342 * region_size.
343 */
344 from.count = ms->ti->len & (region_size - 1);
345 if (!from.count)
346 from.count = region_size;
347 } else
348 from.count = region_size;
349
350 /* fill in the destinations */
351 for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
352 if (&ms->mirror[i] == get_default_mirror(ms))
353 continue;
354
355 m = ms->mirror + i;
356 dest->bdev = m->dev->bdev;
357 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
358 dest->count = from.count;
359 dest++;
360 }
361
362 /* hand to kcopyd */
363 if (!errors_handled(ms))
364 set_bit(DM_KCOPYD_IGNORE_ERROR, &flags);
365
366 r = dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to,
367 flags, recovery_complete, reg);
368
369 return r;
370}
371
372static void do_recovery(struct mirror_set *ms)
373{
374 struct dm_region *reg;
375 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
376 int r;
377
378 /*
379 * Start quiescing some regions.
380 */
381 dm_rh_recovery_prepare(ms->rh);
382
383 /*
384 * Copy any already quiesced regions.
385 */
386 while ((reg = dm_rh_recovery_start(ms->rh))) {
387 r = recover(ms, reg);
388 if (r)
389 dm_rh_recovery_end(reg, 0);
390 }
391
392 /*
393 * Update the in sync flag.
394 */
395 if (!ms->in_sync &&
396 (log->type->get_sync_count(log) == ms->nr_regions)) {
397 /* the sync is complete */
398 dm_table_event(ms->ti->table);
399 ms->in_sync = 1;
400 }
401}
402
403/*-----------------------------------------------------------------
404 * Reads
405 *---------------------------------------------------------------*/
406static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
407{
408 struct mirror *m = get_default_mirror(ms);
409
410 do {
411 if (likely(!atomic_read(&m->error_count)))
412 return m;
413
414 if (m-- == ms->mirror)
415 m += ms->nr_mirrors;
416 } while (m != get_default_mirror(ms));
417
418 return NULL;
419}
420
421static int default_ok(struct mirror *m)
422{
423 struct mirror *default_mirror = get_default_mirror(m->ms);
424
425 return !atomic_read(&default_mirror->error_count);
426}
427
428static int mirror_available(struct mirror_set *ms, struct bio *bio)
429{
430 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
431 region_t region = dm_rh_bio_to_region(ms->rh, bio);
432
433 if (log->type->in_sync(log, region, 0))
434 return choose_mirror(ms, bio->bi_sector) ? 1 : 0;
435
436 return 0;
437}
438
439/*
440 * remap a buffer to a particular mirror.
441 */
442static sector_t map_sector(struct mirror *m, struct bio *bio)
443{
444 if (unlikely(!bio->bi_size))
445 return 0;
446 return m->offset + dm_target_offset(m->ms->ti, bio->bi_sector);
447}
448
449static void map_bio(struct mirror *m, struct bio *bio)
450{
451 bio->bi_bdev = m->dev->bdev;
452 bio->bi_sector = map_sector(m, bio);
453}
454
455static void map_region(struct dm_io_region *io, struct mirror *m,
456 struct bio *bio)
457{
458 io->bdev = m->dev->bdev;
459 io->sector = map_sector(m, bio);
460 io->count = bio->bi_size >> 9;
461}
462
463static void hold_bio(struct mirror_set *ms, struct bio *bio)
464{
465 /*
466 * Lock is required to avoid race condition during suspend
467 * process.
468 */
469 spin_lock_irq(&ms->lock);
470
471 if (atomic_read(&ms->suspend)) {
472 spin_unlock_irq(&ms->lock);
473
474 /*
475 * If device is suspended, complete the bio.
476 */
477 if (dm_noflush_suspending(ms->ti))
478 bio_endio(bio, DM_ENDIO_REQUEUE);
479 else
480 bio_endio(bio, -EIO);
481 return;
482 }
483
484 /*
485 * Hold bio until the suspend is complete.
486 */
487 bio_list_add(&ms->holds, bio);
488 spin_unlock_irq(&ms->lock);
489}
490
491/*-----------------------------------------------------------------
492 * Reads
493 *---------------------------------------------------------------*/
494static void read_callback(unsigned long error, void *context)
495{
496 struct bio *bio = context;
497 struct mirror *m;
498
499 m = bio_get_m(bio);
500 bio_set_m(bio, NULL);
501
502 if (likely(!error)) {
503 bio_endio(bio, 0);
504 return;
505 }
506
507 fail_mirror(m, DM_RAID1_READ_ERROR);
508
509 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
510 DMWARN_LIMIT("Read failure on mirror device %s. "
511 "Trying alternative device.",
512 m->dev->name);
513 queue_bio(m->ms, bio, bio_rw(bio));
514 return;
515 }
516
517 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
518 m->dev->name);
519 bio_endio(bio, -EIO);
520}
521
522/* Asynchronous read. */
523static void read_async_bio(struct mirror *m, struct bio *bio)
524{
525 struct dm_io_region io;
526 struct dm_io_request io_req = {
527 .bi_rw = READ,
528 .mem.type = DM_IO_BVEC,
529 .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
530 .notify.fn = read_callback,
531 .notify.context = bio,
532 .client = m->ms->io_client,
533 };
534
535 map_region(&io, m, bio);
536 bio_set_m(bio, m);
537 BUG_ON(dm_io(&io_req, 1, &io, NULL));
538}
539
540static inline int region_in_sync(struct mirror_set *ms, region_t region,
541 int may_block)
542{
543 int state = dm_rh_get_state(ms->rh, region, may_block);
544 return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
545}
546
547static void do_reads(struct mirror_set *ms, struct bio_list *reads)
548{
549 region_t region;
550 struct bio *bio;
551 struct mirror *m;
552
553 while ((bio = bio_list_pop(reads))) {
554 region = dm_rh_bio_to_region(ms->rh, bio);
555 m = get_default_mirror(ms);
556
557 /*
558 * We can only read balance if the region is in sync.
559 */
560 if (likely(region_in_sync(ms, region, 1)))
561 m = choose_mirror(ms, bio->bi_sector);
562 else if (m && atomic_read(&m->error_count))
563 m = NULL;
564
565 if (likely(m))
566 read_async_bio(m, bio);
567 else
568 bio_endio(bio, -EIO);
569 }
570}
571
572/*-----------------------------------------------------------------
573 * Writes.
574 *
575 * We do different things with the write io depending on the
576 * state of the region that it's in:
577 *
578 * SYNC: increment pending, use kcopyd to write to *all* mirrors
579 * RECOVERING: delay the io until recovery completes
580 * NOSYNC: increment pending, just write to the default mirror
581 *---------------------------------------------------------------*/
582
583
584static void write_callback(unsigned long error, void *context)
585{
586 unsigned i, ret = 0;
587 struct bio *bio = (struct bio *) context;
588 struct mirror_set *ms;
589 int should_wake = 0;
590 unsigned long flags;
591
592 ms = bio_get_m(bio)->ms;
593 bio_set_m(bio, NULL);
594
595 /*
596 * NOTE: We don't decrement the pending count here,
597 * instead it is done by the targets endio function.
598 * This way we handle both writes to SYNC and NOSYNC
599 * regions with the same code.
600 */
601 if (likely(!error)) {
602 bio_endio(bio, ret);
603 return;
604 }
605
606 for (i = 0; i < ms->nr_mirrors; i++)
607 if (test_bit(i, &error))
608 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
609
610 /*
611 * Need to raise event. Since raising
612 * events can block, we need to do it in
613 * the main thread.
614 */
615 spin_lock_irqsave(&ms->lock, flags);
616 if (!ms->failures.head)
617 should_wake = 1;
618 bio_list_add(&ms->failures, bio);
619 spin_unlock_irqrestore(&ms->lock, flags);
620 if (should_wake)
621 wakeup_mirrord(ms);
622}
623
624static void do_write(struct mirror_set *ms, struct bio *bio)
625{
626 unsigned int i;
627 struct dm_io_region io[ms->nr_mirrors], *dest = io;
628 struct mirror *m;
629 struct dm_io_request io_req = {
630 .bi_rw = WRITE | (bio->bi_rw & WRITE_FLUSH_FUA),
631 .mem.type = DM_IO_BVEC,
632 .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
633 .notify.fn = write_callback,
634 .notify.context = bio,
635 .client = ms->io_client,
636 };
637
638 if (bio->bi_rw & REQ_DISCARD) {
639 io_req.bi_rw |= REQ_DISCARD;
640 io_req.mem.type = DM_IO_KMEM;
641 io_req.mem.ptr.addr = NULL;
642 }
643
644 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
645 map_region(dest++, m, bio);
646
647 /*
648 * Use default mirror because we only need it to retrieve the reference
649 * to the mirror set in write_callback().
650 */
651 bio_set_m(bio, get_default_mirror(ms));
652
653 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL));
654}
655
656static void do_writes(struct mirror_set *ms, struct bio_list *writes)
657{
658 int state;
659 struct bio *bio;
660 struct bio_list sync, nosync, recover, *this_list = NULL;
661 struct bio_list requeue;
662 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
663 region_t region;
664
665 if (!writes->head)
666 return;
667
668 /*
669 * Classify each write.
670 */
671 bio_list_init(&sync);
672 bio_list_init(&nosync);
673 bio_list_init(&recover);
674 bio_list_init(&requeue);
675
676 while ((bio = bio_list_pop(writes))) {
677 if ((bio->bi_rw & REQ_FLUSH) ||
678 (bio->bi_rw & REQ_DISCARD)) {
679 bio_list_add(&sync, bio);
680 continue;
681 }
682
683 region = dm_rh_bio_to_region(ms->rh, bio);
684
685 if (log->type->is_remote_recovering &&
686 log->type->is_remote_recovering(log, region)) {
687 bio_list_add(&requeue, bio);
688 continue;
689 }
690
691 state = dm_rh_get_state(ms->rh, region, 1);
692 switch (state) {
693 case DM_RH_CLEAN:
694 case DM_RH_DIRTY:
695 this_list = &sync;
696 break;
697
698 case DM_RH_NOSYNC:
699 this_list = &nosync;
700 break;
701
702 case DM_RH_RECOVERING:
703 this_list = &recover;
704 break;
705 }
706
707 bio_list_add(this_list, bio);
708 }
709
710 /*
711 * Add bios that are delayed due to remote recovery
712 * back on to the write queue
713 */
714 if (unlikely(requeue.head)) {
715 spin_lock_irq(&ms->lock);
716 bio_list_merge(&ms->writes, &requeue);
717 spin_unlock_irq(&ms->lock);
718 delayed_wake(ms);
719 }
720
721 /*
722 * Increment the pending counts for any regions that will
723 * be written to (writes to recover regions are going to
724 * be delayed).
725 */
726 dm_rh_inc_pending(ms->rh, &sync);
727 dm_rh_inc_pending(ms->rh, &nosync);
728
729 /*
730 * If the flush fails on a previous call and succeeds here,
731 * we must not reset the log_failure variable. We need
732 * userspace interaction to do that.
733 */
734 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure;
735
736 /*
737 * Dispatch io.
738 */
739 if (unlikely(ms->log_failure) && errors_handled(ms)) {
740 spin_lock_irq(&ms->lock);
741 bio_list_merge(&ms->failures, &sync);
742 spin_unlock_irq(&ms->lock);
743 wakeup_mirrord(ms);
744 } else
745 while ((bio = bio_list_pop(&sync)))
746 do_write(ms, bio);
747
748 while ((bio = bio_list_pop(&recover)))
749 dm_rh_delay(ms->rh, bio);
750
751 while ((bio = bio_list_pop(&nosync))) {
752 if (unlikely(ms->leg_failure) && errors_handled(ms)) {
753 spin_lock_irq(&ms->lock);
754 bio_list_add(&ms->failures, bio);
755 spin_unlock_irq(&ms->lock);
756 wakeup_mirrord(ms);
757 } else {
758 map_bio(get_default_mirror(ms), bio);
759 generic_make_request(bio);
760 }
761 }
762}
763
764static void do_failures(struct mirror_set *ms, struct bio_list *failures)
765{
766 struct bio *bio;
767
768 if (likely(!failures->head))
769 return;
770
771 /*
772 * If the log has failed, unattempted writes are being
773 * put on the holds list. We can't issue those writes
774 * until a log has been marked, so we must store them.
775 *
776 * If a 'noflush' suspend is in progress, we can requeue
777 * the I/O's to the core. This give userspace a chance
778 * to reconfigure the mirror, at which point the core
779 * will reissue the writes. If the 'noflush' flag is
780 * not set, we have no choice but to return errors.
781 *
782 * Some writes on the failures list may have been
783 * submitted before the log failure and represent a
784 * failure to write to one of the devices. It is ok
785 * for us to treat them the same and requeue them
786 * as well.
787 */
788 while ((bio = bio_list_pop(failures))) {
789 if (!ms->log_failure) {
790 ms->in_sync = 0;
791 dm_rh_mark_nosync(ms->rh, bio);
792 }
793
794 /*
795 * If all the legs are dead, fail the I/O.
796 * If we have been told to handle errors, hold the bio
797 * and wait for userspace to deal with the problem.
798 * Otherwise pretend that the I/O succeeded. (This would
799 * be wrong if the failed leg returned after reboot and
800 * got replicated back to the good legs.)
801 */
802 if (!get_valid_mirror(ms))
803 bio_endio(bio, -EIO);
804 else if (errors_handled(ms))
805 hold_bio(ms, bio);
806 else
807 bio_endio(bio, 0);
808 }
809}
810
811static void trigger_event(struct work_struct *work)
812{
813 struct mirror_set *ms =
814 container_of(work, struct mirror_set, trigger_event);
815
816 dm_table_event(ms->ti->table);
817}
818
819/*-----------------------------------------------------------------
820 * kmirrord
821 *---------------------------------------------------------------*/
822static void do_mirror(struct work_struct *work)
823{
824 struct mirror_set *ms = container_of(work, struct mirror_set,
825 kmirrord_work);
826 struct bio_list reads, writes, failures;
827 unsigned long flags;
828
829 spin_lock_irqsave(&ms->lock, flags);
830 reads = ms->reads;
831 writes = ms->writes;
832 failures = ms->failures;
833 bio_list_init(&ms->reads);
834 bio_list_init(&ms->writes);
835 bio_list_init(&ms->failures);
836 spin_unlock_irqrestore(&ms->lock, flags);
837
838 dm_rh_update_states(ms->rh, errors_handled(ms));
839 do_recovery(ms);
840 do_reads(ms, &reads);
841 do_writes(ms, &writes);
842 do_failures(ms, &failures);
843}
844
845/*-----------------------------------------------------------------
846 * Target functions
847 *---------------------------------------------------------------*/
848static struct mirror_set *alloc_context(unsigned int nr_mirrors,
849 uint32_t region_size,
850 struct dm_target *ti,
851 struct dm_dirty_log *dl)
852{
853 size_t len;
854 struct mirror_set *ms = NULL;
855
856 len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors);
857
858 ms = kzalloc(len, GFP_KERNEL);
859 if (!ms) {
860 ti->error = "Cannot allocate mirror context";
861 return NULL;
862 }
863
864 spin_lock_init(&ms->lock);
865 bio_list_init(&ms->reads);
866 bio_list_init(&ms->writes);
867 bio_list_init(&ms->failures);
868 bio_list_init(&ms->holds);
869
870 ms->ti = ti;
871 ms->nr_mirrors = nr_mirrors;
872 ms->nr_regions = dm_sector_div_up(ti->len, region_size);
873 ms->in_sync = 0;
874 ms->log_failure = 0;
875 ms->leg_failure = 0;
876 atomic_set(&ms->suspend, 0);
877 atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
878
879 ms->read_record_pool = mempool_create_slab_pool(MIN_READ_RECORDS,
880 _dm_raid1_read_record_cache);
881
882 if (!ms->read_record_pool) {
883 ti->error = "Error creating mirror read_record_pool";
884 kfree(ms);
885 return NULL;
886 }
887
888 ms->io_client = dm_io_client_create();
889 if (IS_ERR(ms->io_client)) {
890 ti->error = "Error creating dm_io client";
891 mempool_destroy(ms->read_record_pool);
892 kfree(ms);
893 return NULL;
894 }
895
896 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
897 wakeup_all_recovery_waiters,
898 ms->ti->begin, MAX_RECOVERY,
899 dl, region_size, ms->nr_regions);
900 if (IS_ERR(ms->rh)) {
901 ti->error = "Error creating dirty region hash";
902 dm_io_client_destroy(ms->io_client);
903 mempool_destroy(ms->read_record_pool);
904 kfree(ms);
905 return NULL;
906 }
907
908 return ms;
909}
910
911static void free_context(struct mirror_set *ms, struct dm_target *ti,
912 unsigned int m)
913{
914 while (m--)
915 dm_put_device(ti, ms->mirror[m].dev);
916
917 dm_io_client_destroy(ms->io_client);
918 dm_region_hash_destroy(ms->rh);
919 mempool_destroy(ms->read_record_pool);
920 kfree(ms);
921}
922
923static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
924 unsigned int mirror, char **argv)
925{
926 unsigned long long offset;
927
928 if (sscanf(argv[1], "%llu", &offset) != 1) {
929 ti->error = "Invalid offset";
930 return -EINVAL;
931 }
932
933 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
934 &ms->mirror[mirror].dev)) {
935 ti->error = "Device lookup failure";
936 return -ENXIO;
937 }
938
939 ms->mirror[mirror].ms = ms;
940 atomic_set(&(ms->mirror[mirror].error_count), 0);
941 ms->mirror[mirror].error_type = 0;
942 ms->mirror[mirror].offset = offset;
943
944 return 0;
945}
946
947/*
948 * Create dirty log: log_type #log_params <log_params>
949 */
950static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
951 unsigned argc, char **argv,
952 unsigned *args_used)
953{
954 unsigned param_count;
955 struct dm_dirty_log *dl;
956
957 if (argc < 2) {
958 ti->error = "Insufficient mirror log arguments";
959 return NULL;
960 }
961
962 if (sscanf(argv[1], "%u", ¶m_count) != 1) {
963 ti->error = "Invalid mirror log argument count";
964 return NULL;
965 }
966
967 *args_used = 2 + param_count;
968
969 if (argc < *args_used) {
970 ti->error = "Insufficient mirror log arguments";
971 return NULL;
972 }
973
974 dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
975 argv + 2);
976 if (!dl) {
977 ti->error = "Error creating mirror dirty log";
978 return NULL;
979 }
980
981 return dl;
982}
983
984static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
985 unsigned *args_used)
986{
987 unsigned num_features;
988 struct dm_target *ti = ms->ti;
989
990 *args_used = 0;
991
992 if (!argc)
993 return 0;
994
995 if (sscanf(argv[0], "%u", &num_features) != 1) {
996 ti->error = "Invalid number of features";
997 return -EINVAL;
998 }
999
1000 argc--;
1001 argv++;
1002 (*args_used)++;
1003
1004 if (num_features > argc) {
1005 ti->error = "Not enough arguments to support feature count";
1006 return -EINVAL;
1007 }
1008
1009 if (!strcmp("handle_errors", argv[0]))
1010 ms->features |= DM_RAID1_HANDLE_ERRORS;
1011 else {
1012 ti->error = "Unrecognised feature requested";
1013 return -EINVAL;
1014 }
1015
1016 (*args_used)++;
1017
1018 return 0;
1019}
1020
1021/*
1022 * Construct a mirror mapping:
1023 *
1024 * log_type #log_params <log_params>
1025 * #mirrors [mirror_path offset]{2,}
1026 * [#features <features>]
1027 *
1028 * log_type is "core" or "disk"
1029 * #log_params is between 1 and 3
1030 *
1031 * If present, features must be "handle_errors".
1032 */
1033static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1034{
1035 int r;
1036 unsigned int nr_mirrors, m, args_used;
1037 struct mirror_set *ms;
1038 struct dm_dirty_log *dl;
1039
1040 dl = create_dirty_log(ti, argc, argv, &args_used);
1041 if (!dl)
1042 return -EINVAL;
1043
1044 argv += args_used;
1045 argc -= args_used;
1046
1047 if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 ||
1048 nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) {
1049 ti->error = "Invalid number of mirrors";
1050 dm_dirty_log_destroy(dl);
1051 return -EINVAL;
1052 }
1053
1054 argv++, argc--;
1055
1056 if (argc < nr_mirrors * 2) {
1057 ti->error = "Too few mirror arguments";
1058 dm_dirty_log_destroy(dl);
1059 return -EINVAL;
1060 }
1061
1062 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
1063 if (!ms) {
1064 dm_dirty_log_destroy(dl);
1065 return -ENOMEM;
1066 }
1067
1068 /* Get the mirror parameter sets */
1069 for (m = 0; m < nr_mirrors; m++) {
1070 r = get_mirror(ms, ti, m, argv);
1071 if (r) {
1072 free_context(ms, ti, m);
1073 return r;
1074 }
1075 argv += 2;
1076 argc -= 2;
1077 }
1078
1079 ti->private = ms;
1080 ti->split_io = dm_rh_get_region_size(ms->rh);
1081 ti->num_flush_requests = 1;
1082 ti->num_discard_requests = 1;
1083
1084 ms->kmirrord_wq = alloc_workqueue("kmirrord",
1085 WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
1086 if (!ms->kmirrord_wq) {
1087 DMERR("couldn't start kmirrord");
1088 r = -ENOMEM;
1089 goto err_free_context;
1090 }
1091 INIT_WORK(&ms->kmirrord_work, do_mirror);
1092 init_timer(&ms->timer);
1093 ms->timer_pending = 0;
1094 INIT_WORK(&ms->trigger_event, trigger_event);
1095
1096 r = parse_features(ms, argc, argv, &args_used);
1097 if (r)
1098 goto err_destroy_wq;
1099
1100 argv += args_used;
1101 argc -= args_used;
1102
1103 /*
1104 * Any read-balancing addition depends on the
1105 * DM_RAID1_HANDLE_ERRORS flag being present.
1106 * This is because the decision to balance depends
1107 * on the sync state of a region. If the above
1108 * flag is not present, we ignore errors; and
1109 * the sync state may be inaccurate.
1110 */
1111
1112 if (argc) {
1113 ti->error = "Too many mirror arguments";
1114 r = -EINVAL;
1115 goto err_destroy_wq;
1116 }
1117
1118 ms->kcopyd_client = dm_kcopyd_client_create();
1119 if (IS_ERR(ms->kcopyd_client)) {
1120 r = PTR_ERR(ms->kcopyd_client);
1121 goto err_destroy_wq;
1122 }
1123
1124 wakeup_mirrord(ms);
1125 return 0;
1126
1127err_destroy_wq:
1128 destroy_workqueue(ms->kmirrord_wq);
1129err_free_context:
1130 free_context(ms, ti, ms->nr_mirrors);
1131 return r;
1132}
1133
1134static void mirror_dtr(struct dm_target *ti)
1135{
1136 struct mirror_set *ms = (struct mirror_set *) ti->private;
1137
1138 del_timer_sync(&ms->timer);
1139 flush_workqueue(ms->kmirrord_wq);
1140 flush_work_sync(&ms->trigger_event);
1141 dm_kcopyd_client_destroy(ms->kcopyd_client);
1142 destroy_workqueue(ms->kmirrord_wq);
1143 free_context(ms, ti, ms->nr_mirrors);
1144}
1145
1146/*
1147 * Mirror mapping function
1148 */
1149static int mirror_map(struct dm_target *ti, struct bio *bio,
1150 union map_info *map_context)
1151{
1152 int r, rw = bio_rw(bio);
1153 struct mirror *m;
1154 struct mirror_set *ms = ti->private;
1155 struct dm_raid1_read_record *read_record = NULL;
1156 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1157
1158 if (rw == WRITE) {
1159 /* Save region for mirror_end_io() handler */
1160 map_context->ll = dm_rh_bio_to_region(ms->rh, bio);
1161 queue_bio(ms, bio, rw);
1162 return DM_MAPIO_SUBMITTED;
1163 }
1164
1165 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
1166 if (r < 0 && r != -EWOULDBLOCK)
1167 return r;
1168
1169 /*
1170 * If region is not in-sync queue the bio.
1171 */
1172 if (!r || (r == -EWOULDBLOCK)) {
1173 if (rw == READA)
1174 return -EWOULDBLOCK;
1175
1176 queue_bio(ms, bio, rw);
1177 return DM_MAPIO_SUBMITTED;
1178 }
1179
1180 /*
1181 * The region is in-sync and we can perform reads directly.
1182 * Store enough information so we can retry if it fails.
1183 */
1184 m = choose_mirror(ms, bio->bi_sector);
1185 if (unlikely(!m))
1186 return -EIO;
1187
1188 read_record = mempool_alloc(ms->read_record_pool, GFP_NOIO);
1189 if (likely(read_record)) {
1190 dm_bio_record(&read_record->details, bio);
1191 map_context->ptr = read_record;
1192 read_record->m = m;
1193 }
1194
1195 map_bio(m, bio);
1196
1197 return DM_MAPIO_REMAPPED;
1198}
1199
1200static int mirror_end_io(struct dm_target *ti, struct bio *bio,
1201 int error, union map_info *map_context)
1202{
1203 int rw = bio_rw(bio);
1204 struct mirror_set *ms = (struct mirror_set *) ti->private;
1205 struct mirror *m = NULL;
1206 struct dm_bio_details *bd = NULL;
1207 struct dm_raid1_read_record *read_record = map_context->ptr;
1208
1209 /*
1210 * We need to dec pending if this was a write.
1211 */
1212 if (rw == WRITE) {
1213 if (!(bio->bi_rw & REQ_FLUSH))
1214 dm_rh_dec(ms->rh, map_context->ll);
1215 return error;
1216 }
1217
1218 if (error == -EOPNOTSUPP)
1219 goto out;
1220
1221 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
1222 goto out;
1223
1224 if (unlikely(error)) {
1225 if (!read_record) {
1226 /*
1227 * There wasn't enough memory to record necessary
1228 * information for a retry or there was no other
1229 * mirror in-sync.
1230 */
1231 DMERR_LIMIT("Mirror read failed.");
1232 return -EIO;
1233 }
1234
1235 m = read_record->m;
1236
1237 DMERR("Mirror read failed from %s. Trying alternative device.",
1238 m->dev->name);
1239
1240 fail_mirror(m, DM_RAID1_READ_ERROR);
1241
1242 /*
1243 * A failed read is requeued for another attempt using an intact
1244 * mirror.
1245 */
1246 if (default_ok(m) || mirror_available(ms, bio)) {
1247 bd = &read_record->details;
1248
1249 dm_bio_restore(bd, bio);
1250 mempool_free(read_record, ms->read_record_pool);
1251 map_context->ptr = NULL;
1252 queue_bio(ms, bio, rw);
1253 return 1;
1254 }
1255 DMERR("All replicated volumes dead, failing I/O");
1256 }
1257
1258out:
1259 if (read_record) {
1260 mempool_free(read_record, ms->read_record_pool);
1261 map_context->ptr = NULL;
1262 }
1263
1264 return error;
1265}
1266
1267static void mirror_presuspend(struct dm_target *ti)
1268{
1269 struct mirror_set *ms = (struct mirror_set *) ti->private;
1270 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1271
1272 struct bio_list holds;
1273 struct bio *bio;
1274
1275 atomic_set(&ms->suspend, 1);
1276
1277 /*
1278 * Process bios in the hold list to start recovery waiting
1279 * for bios in the hold list. After the process, no bio has
1280 * a chance to be added in the hold list because ms->suspend
1281 * is set.
1282 */
1283 spin_lock_irq(&ms->lock);
1284 holds = ms->holds;
1285 bio_list_init(&ms->holds);
1286 spin_unlock_irq(&ms->lock);
1287
1288 while ((bio = bio_list_pop(&holds)))
1289 hold_bio(ms, bio);
1290
1291 /*
1292 * We must finish up all the work that we've
1293 * generated (i.e. recovery work).
1294 */
1295 dm_rh_stop_recovery(ms->rh);
1296
1297 wait_event(_kmirrord_recovery_stopped,
1298 !dm_rh_recovery_in_flight(ms->rh));
1299
1300 if (log->type->presuspend && log->type->presuspend(log))
1301 /* FIXME: need better error handling */
1302 DMWARN("log presuspend failed");
1303
1304 /*
1305 * Now that recovery is complete/stopped and the
1306 * delayed bios are queued, we need to wait for
1307 * the worker thread to complete. This way,
1308 * we know that all of our I/O has been pushed.
1309 */
1310 flush_workqueue(ms->kmirrord_wq);
1311}
1312
1313static void mirror_postsuspend(struct dm_target *ti)
1314{
1315 struct mirror_set *ms = ti->private;
1316 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1317
1318 if (log->type->postsuspend && log->type->postsuspend(log))
1319 /* FIXME: need better error handling */
1320 DMWARN("log postsuspend failed");
1321}
1322
1323static void mirror_resume(struct dm_target *ti)
1324{
1325 struct mirror_set *ms = ti->private;
1326 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1327
1328 atomic_set(&ms->suspend, 0);
1329 if (log->type->resume && log->type->resume(log))
1330 /* FIXME: need better error handling */
1331 DMWARN("log resume failed");
1332 dm_rh_start_recovery(ms->rh);
1333}
1334
1335/*
1336 * device_status_char
1337 * @m: mirror device/leg we want the status of
1338 *
1339 * We return one character representing the most severe error
1340 * we have encountered.
1341 * A => Alive - No failures
1342 * D => Dead - A write failure occurred leaving mirror out-of-sync
1343 * S => Sync - A sychronization failure occurred, mirror out-of-sync
1344 * R => Read - A read failure occurred, mirror data unaffected
1345 *
1346 * Returns: <char>
1347 */
1348static char device_status_char(struct mirror *m)
1349{
1350 if (!atomic_read(&(m->error_count)))
1351 return 'A';
1352
1353 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
1354 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
1355 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
1356 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
1357}
1358
1359
1360static int mirror_status(struct dm_target *ti, status_type_t type,
1361 char *result, unsigned int maxlen)
1362{
1363 unsigned int m, sz = 0;
1364 struct mirror_set *ms = (struct mirror_set *) ti->private;
1365 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1366 char buffer[ms->nr_mirrors + 1];
1367
1368 switch (type) {
1369 case STATUSTYPE_INFO:
1370 DMEMIT("%d ", ms->nr_mirrors);
1371 for (m = 0; m < ms->nr_mirrors; m++) {
1372 DMEMIT("%s ", ms->mirror[m].dev->name);
1373 buffer[m] = device_status_char(&(ms->mirror[m]));
1374 }
1375 buffer[m] = '\0';
1376
1377 DMEMIT("%llu/%llu 1 %s ",
1378 (unsigned long long)log->type->get_sync_count(log),
1379 (unsigned long long)ms->nr_regions, buffer);
1380
1381 sz += log->type->status(log, type, result+sz, maxlen-sz);
1382
1383 break;
1384
1385 case STATUSTYPE_TABLE:
1386 sz = log->type->status(log, type, result, maxlen);
1387
1388 DMEMIT("%d", ms->nr_mirrors);
1389 for (m = 0; m < ms->nr_mirrors; m++)
1390 DMEMIT(" %s %llu", ms->mirror[m].dev->name,
1391 (unsigned long long)ms->mirror[m].offset);
1392
1393 if (ms->features & DM_RAID1_HANDLE_ERRORS)
1394 DMEMIT(" 1 handle_errors");
1395 }
1396
1397 return 0;
1398}
1399
1400static int mirror_iterate_devices(struct dm_target *ti,
1401 iterate_devices_callout_fn fn, void *data)
1402{
1403 struct mirror_set *ms = ti->private;
1404 int ret = 0;
1405 unsigned i;
1406
1407 for (i = 0; !ret && i < ms->nr_mirrors; i++)
1408 ret = fn(ti, ms->mirror[i].dev,
1409 ms->mirror[i].offset, ti->len, data);
1410
1411 return ret;
1412}
1413
1414static struct target_type mirror_target = {
1415 .name = "mirror",
1416 .version = {1, 12, 1},
1417 .module = THIS_MODULE,
1418 .ctr = mirror_ctr,
1419 .dtr = mirror_dtr,
1420 .map = mirror_map,
1421 .end_io = mirror_end_io,
1422 .presuspend = mirror_presuspend,
1423 .postsuspend = mirror_postsuspend,
1424 .resume = mirror_resume,
1425 .status = mirror_status,
1426 .iterate_devices = mirror_iterate_devices,
1427};
1428
1429static int __init dm_mirror_init(void)
1430{
1431 int r;
1432
1433 _dm_raid1_read_record_cache = KMEM_CACHE(dm_raid1_read_record, 0);
1434 if (!_dm_raid1_read_record_cache) {
1435 DMERR("Can't allocate dm_raid1_read_record cache");
1436 r = -ENOMEM;
1437 goto bad_cache;
1438 }
1439
1440 r = dm_register_target(&mirror_target);
1441 if (r < 0) {
1442 DMERR("Failed to register mirror target");
1443 goto bad_target;
1444 }
1445
1446 return 0;
1447
1448bad_target:
1449 kmem_cache_destroy(_dm_raid1_read_record_cache);
1450bad_cache:
1451 return r;
1452}
1453
1454static void __exit dm_mirror_exit(void)
1455{
1456 dm_unregister_target(&mirror_target);
1457 kmem_cache_destroy(_dm_raid1_read_record_cache);
1458}
1459
1460/* Module hooks */
1461module_init(dm_mirror_init);
1462module_exit(dm_mirror_exit);
1463
1464MODULE_DESCRIPTION(DM_NAME " mirror target");
1465MODULE_AUTHOR("Joe Thornber");
1466MODULE_LICENSE("GPL");
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(ms->kmirrord_wq, &ms->kmirrord_work);
102}
103
104static void delayed_wake_fn(struct timer_list *t)
105{
106 struct mirror_set *ms = from_timer(ms, t, timer);
107
108 clear_bit(0, &ms->timer_pending);
109 wakeup_mirrord(ms);
110}
111
112static void delayed_wake(struct mirror_set *ms)
113{
114 if (test_and_set_bit(0, &ms->timer_pending))
115 return;
116
117 ms->timer.expires = jiffies + HZ / 5;
118 add_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 spin_unlock_irqrestore(&ms->lock, flags);
137
138 if (should_wake)
139 wakeup_mirrord(ms);
140}
141
142static void dispatch_bios(void *context, struct bio_list *bio_list)
143{
144 struct mirror_set *ms = context;
145 struct bio *bio;
146
147 while ((bio = bio_list_pop(bio_list)))
148 queue_bio(ms, bio, WRITE);
149}
150
151struct dm_raid1_bio_record {
152 struct mirror *m;
153 /* if details->bi_bdev == NULL, details were not saved */
154 struct dm_bio_details details;
155 region_t write_region;
156};
157
158/*
159 * Every mirror should look like this one.
160 */
161#define DEFAULT_MIRROR 0
162
163/*
164 * This is yucky. We squirrel the mirror struct away inside
165 * bi_next for read/write buffers. This is safe since the bh
166 * doesn't get submitted to the lower levels of block layer.
167 */
168static struct mirror *bio_get_m(struct bio *bio)
169{
170 return (struct mirror *) bio->bi_next;
171}
172
173static void bio_set_m(struct bio *bio, struct mirror *m)
174{
175 bio->bi_next = (struct bio *) m;
176}
177
178static struct mirror *get_default_mirror(struct mirror_set *ms)
179{
180 return &ms->mirror[atomic_read(&ms->default_mirror)];
181}
182
183static void set_default_mirror(struct mirror *m)
184{
185 struct mirror_set *ms = m->ms;
186 struct mirror *m0 = &(ms->mirror[0]);
187
188 atomic_set(&ms->default_mirror, m - m0);
189}
190
191static struct mirror *get_valid_mirror(struct mirror_set *ms)
192{
193 struct mirror *m;
194
195 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
196 if (!atomic_read(&m->error_count))
197 return m;
198
199 return NULL;
200}
201
202/* fail_mirror
203 * @m: mirror device to fail
204 * @error_type: one of the enum's, DM_RAID1_*_ERROR
205 *
206 * If errors are being handled, record the type of
207 * error encountered for this device. If this type
208 * of error has already been recorded, we can return;
209 * otherwise, we must signal userspace by triggering
210 * an event. Additionally, if the device is the
211 * primary device, we must choose a new primary, but
212 * only if the mirror is in-sync.
213 *
214 * This function must not block.
215 */
216static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
217{
218 struct mirror_set *ms = m->ms;
219 struct mirror *new;
220
221 ms->leg_failure = 1;
222
223 /*
224 * error_count is used for nothing more than a
225 * simple way to tell if a device has encountered
226 * errors.
227 */
228 atomic_inc(&m->error_count);
229
230 if (test_and_set_bit(error_type, &m->error_type))
231 return;
232
233 if (!errors_handled(ms))
234 return;
235
236 if (m != get_default_mirror(ms))
237 goto out;
238
239 if (!ms->in_sync && !keep_log(ms)) {
240 /*
241 * Better to issue requests to same failing device
242 * than to risk returning corrupt data.
243 */
244 DMERR("Primary mirror (%s) failed while out-of-sync: Reads may fail.",
245 m->dev->name);
246 goto out;
247 }
248
249 new = get_valid_mirror(ms);
250 if (new)
251 set_default_mirror(new);
252 else
253 DMWARN("All sides of mirror have failed.");
254
255out:
256 queue_work(dm_raid1_wq, &ms->trigger_event);
257}
258
259static int mirror_flush(struct dm_target *ti)
260{
261 struct mirror_set *ms = ti->private;
262 unsigned long error_bits;
263
264 unsigned int i;
265 struct dm_io_region io[MAX_NR_MIRRORS];
266 struct mirror *m;
267 struct dm_io_request io_req = {
268 .bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC,
269 .mem.type = DM_IO_KMEM,
270 .mem.ptr.addr = NULL,
271 .client = ms->io_client,
272 };
273
274 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
275 io[i].bdev = m->dev->bdev;
276 io[i].sector = 0;
277 io[i].count = 0;
278 }
279
280 error_bits = -1;
281 dm_io(&io_req, ms->nr_mirrors, io, &error_bits, IOPRIO_DEFAULT);
282 if (unlikely(error_bits != 0)) {
283 for (i = 0; i < ms->nr_mirrors; i++)
284 if (test_bit(i, &error_bits))
285 fail_mirror(ms->mirror + i,
286 DM_RAID1_FLUSH_ERROR);
287 return -EIO;
288 }
289
290 return 0;
291}
292
293/*
294 *---------------------------------------------------------------
295 * Recovery.
296 *
297 * When a mirror is first activated we may find that some regions
298 * are in the no-sync state. We have to recover these by
299 * recopying from the default mirror to all the others.
300 *---------------------------------------------------------------
301 */
302static void recovery_complete(int read_err, unsigned long write_err,
303 void *context)
304{
305 struct dm_region *reg = context;
306 struct mirror_set *ms = dm_rh_region_context(reg);
307 int m, bit = 0;
308
309 if (read_err) {
310 /* Read error means the failure of default mirror. */
311 DMERR_LIMIT("Unable to read primary mirror during recovery");
312 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR);
313 }
314
315 if (write_err) {
316 DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
317 write_err);
318 /*
319 * Bits correspond to devices (excluding default mirror).
320 * The default mirror cannot change during recovery.
321 */
322 for (m = 0; m < ms->nr_mirrors; m++) {
323 if (&ms->mirror[m] == get_default_mirror(ms))
324 continue;
325 if (test_bit(bit, &write_err))
326 fail_mirror(ms->mirror + m,
327 DM_RAID1_SYNC_ERROR);
328 bit++;
329 }
330 }
331
332 dm_rh_recovery_end(reg, !(read_err || write_err));
333}
334
335static void recover(struct mirror_set *ms, struct dm_region *reg)
336{
337 unsigned int i;
338 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
339 struct mirror *m;
340 unsigned long flags = 0;
341 region_t key = dm_rh_get_region_key(reg);
342 sector_t region_size = dm_rh_get_region_size(ms->rh);
343
344 /* fill in the source */
345 m = get_default_mirror(ms);
346 from.bdev = m->dev->bdev;
347 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
348 if (key == (ms->nr_regions - 1)) {
349 /*
350 * The final region may be smaller than
351 * region_size.
352 */
353 from.count = ms->ti->len & (region_size - 1);
354 if (!from.count)
355 from.count = region_size;
356 } else
357 from.count = region_size;
358
359 /* fill in the destinations */
360 for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
361 if (&ms->mirror[i] == get_default_mirror(ms))
362 continue;
363
364 m = ms->mirror + i;
365 dest->bdev = m->dev->bdev;
366 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
367 dest->count = from.count;
368 dest++;
369 }
370
371 /* hand to kcopyd */
372 if (!errors_handled(ms))
373 flags |= BIT(DM_KCOPYD_IGNORE_ERROR);
374
375 dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to,
376 flags, recovery_complete, reg);
377}
378
379static void reset_ms_flags(struct mirror_set *ms)
380{
381 unsigned int m;
382
383 ms->leg_failure = 0;
384 for (m = 0; m < ms->nr_mirrors; m++) {
385 atomic_set(&(ms->mirror[m].error_count), 0);
386 ms->mirror[m].error_type = 0;
387 }
388}
389
390static void do_recovery(struct mirror_set *ms)
391{
392 struct dm_region *reg;
393 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
394
395 /*
396 * Start quiescing some regions.
397 */
398 dm_rh_recovery_prepare(ms->rh);
399
400 /*
401 * Copy any already quiesced regions.
402 */
403 while ((reg = dm_rh_recovery_start(ms->rh)))
404 recover(ms, reg);
405
406 /*
407 * Update the in sync flag.
408 */
409 if (!ms->in_sync &&
410 (log->type->get_sync_count(log) == ms->nr_regions)) {
411 /* the sync is complete */
412 dm_table_event(ms->ti->table);
413 ms->in_sync = 1;
414 reset_ms_flags(ms);
415 }
416}
417
418/*
419 *---------------------------------------------------------------
420 * Reads
421 *---------------------------------------------------------------
422 */
423static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
424{
425 struct mirror *m = get_default_mirror(ms);
426
427 do {
428 if (likely(!atomic_read(&m->error_count)))
429 return m;
430
431 if (m-- == ms->mirror)
432 m += ms->nr_mirrors;
433 } while (m != get_default_mirror(ms));
434
435 return NULL;
436}
437
438static int default_ok(struct mirror *m)
439{
440 struct mirror *default_mirror = get_default_mirror(m->ms);
441
442 return !atomic_read(&default_mirror->error_count);
443}
444
445static int mirror_available(struct mirror_set *ms, struct bio *bio)
446{
447 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
448 region_t region = dm_rh_bio_to_region(ms->rh, bio);
449
450 if (log->type->in_sync(log, region, 0))
451 return choose_mirror(ms, bio->bi_iter.bi_sector) ? 1 : 0;
452
453 return 0;
454}
455
456/*
457 * remap a buffer to a particular mirror.
458 */
459static sector_t map_sector(struct mirror *m, struct bio *bio)
460{
461 if (unlikely(!bio->bi_iter.bi_size))
462 return 0;
463 return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector);
464}
465
466static void map_bio(struct mirror *m, struct bio *bio)
467{
468 bio_set_dev(bio, m->dev->bdev);
469 bio->bi_iter.bi_sector = map_sector(m, bio);
470}
471
472static void map_region(struct dm_io_region *io, struct mirror *m,
473 struct bio *bio)
474{
475 io->bdev = m->dev->bdev;
476 io->sector = map_sector(m, bio);
477 io->count = bio_sectors(bio);
478}
479
480static void hold_bio(struct mirror_set *ms, struct bio *bio)
481{
482 /*
483 * Lock is required to avoid race condition during suspend
484 * process.
485 */
486 spin_lock_irq(&ms->lock);
487
488 if (atomic_read(&ms->suspend)) {
489 spin_unlock_irq(&ms->lock);
490
491 /*
492 * If device is suspended, complete the bio.
493 */
494 if (dm_noflush_suspending(ms->ti))
495 bio->bi_status = BLK_STS_DM_REQUEUE;
496 else
497 bio->bi_status = BLK_STS_IOERR;
498
499 bio_endio(bio);
500 return;
501 }
502
503 /*
504 * Hold bio until the suspend is complete.
505 */
506 bio_list_add(&ms->holds, bio);
507 spin_unlock_irq(&ms->lock);
508}
509
510/*
511 *---------------------------------------------------------------
512 * Reads
513 *---------------------------------------------------------------
514 */
515static void read_callback(unsigned long error, void *context)
516{
517 struct bio *bio = context;
518 struct mirror *m;
519
520 m = bio_get_m(bio);
521 bio_set_m(bio, NULL);
522
523 if (likely(!error)) {
524 bio_endio(bio);
525 return;
526 }
527
528 fail_mirror(m, DM_RAID1_READ_ERROR);
529
530 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
531 DMWARN_LIMIT("Read failure on mirror device %s. Trying alternative device.",
532 m->dev->name);
533 queue_bio(m->ms, bio, bio_data_dir(bio));
534 return;
535 }
536
537 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
538 m->dev->name);
539 bio_io_error(bio);
540}
541
542/* Asynchronous read. */
543static void read_async_bio(struct mirror *m, struct bio *bio)
544{
545 struct dm_io_region io;
546 struct dm_io_request io_req = {
547 .bi_opf = REQ_OP_READ,
548 .mem.type = DM_IO_BIO,
549 .mem.ptr.bio = bio,
550 .notify.fn = read_callback,
551 .notify.context = bio,
552 .client = m->ms->io_client,
553 };
554
555 map_region(&io, m, bio);
556 bio_set_m(bio, m);
557 BUG_ON(dm_io(&io_req, 1, &io, NULL, IOPRIO_DEFAULT));
558}
559
560static inline int region_in_sync(struct mirror_set *ms, region_t region,
561 int may_block)
562{
563 int state = dm_rh_get_state(ms->rh, region, may_block);
564 return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
565}
566
567static void do_reads(struct mirror_set *ms, struct bio_list *reads)
568{
569 region_t region;
570 struct bio *bio;
571 struct mirror *m;
572
573 while ((bio = bio_list_pop(reads))) {
574 region = dm_rh_bio_to_region(ms->rh, bio);
575 m = get_default_mirror(ms);
576
577 /*
578 * We can only read balance if the region is in sync.
579 */
580 if (likely(region_in_sync(ms, region, 1)))
581 m = choose_mirror(ms, bio->bi_iter.bi_sector);
582 else if (m && atomic_read(&m->error_count))
583 m = NULL;
584
585 if (likely(m))
586 read_async_bio(m, bio);
587 else
588 bio_io_error(bio);
589 }
590}
591
592/*
593 *---------------------------------------------------------------------
594 * Writes.
595 *
596 * We do different things with the write io depending on the
597 * state of the region that it's in:
598 *
599 * SYNC: increment pending, use kcopyd to write to *all* mirrors
600 * RECOVERING: delay the io until recovery completes
601 * NOSYNC: increment pending, just write to the default mirror
602 *---------------------------------------------------------------------
603 */
604static void write_callback(unsigned long error, void *context)
605{
606 unsigned int i;
607 struct bio *bio = context;
608 struct mirror_set *ms;
609 int should_wake = 0;
610 unsigned long flags;
611
612 ms = bio_get_m(bio)->ms;
613 bio_set_m(bio, NULL);
614
615 /*
616 * NOTE: We don't decrement the pending count here,
617 * instead it is done by the targets endio function.
618 * This way we handle both writes to SYNC and NOSYNC
619 * regions with the same code.
620 */
621 if (likely(!error)) {
622 bio_endio(bio);
623 return;
624 }
625
626 /*
627 * If the bio is discard, return an error, but do not
628 * degrade the array.
629 */
630 if (bio_op(bio) == REQ_OP_DISCARD) {
631 bio->bi_status = BLK_STS_NOTSUPP;
632 bio_endio(bio);
633 return;
634 }
635
636 for (i = 0; i < ms->nr_mirrors; i++)
637 if (test_bit(i, &error))
638 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
639
640 /*
641 * Need to raise event. Since raising
642 * events can block, we need to do it in
643 * the main thread.
644 */
645 spin_lock_irqsave(&ms->lock, flags);
646 if (!ms->failures.head)
647 should_wake = 1;
648 bio_list_add(&ms->failures, bio);
649 spin_unlock_irqrestore(&ms->lock, flags);
650 if (should_wake)
651 wakeup_mirrord(ms);
652}
653
654static void do_write(struct mirror_set *ms, struct bio *bio)
655{
656 unsigned int i;
657 struct dm_io_region io[MAX_NR_MIRRORS], *dest = io;
658 struct mirror *m;
659 blk_opf_t op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH);
660 struct dm_io_request io_req = {
661 .bi_opf = REQ_OP_WRITE | op_flags,
662 .mem.type = DM_IO_BIO,
663 .mem.ptr.bio = bio,
664 .notify.fn = write_callback,
665 .notify.context = bio,
666 .client = ms->io_client,
667 };
668
669 if (bio_op(bio) == REQ_OP_DISCARD) {
670 io_req.bi_opf = REQ_OP_DISCARD | op_flags;
671 io_req.mem.type = DM_IO_KMEM;
672 io_req.mem.ptr.addr = NULL;
673 }
674
675 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
676 map_region(dest++, m, bio);
677
678 /*
679 * Use default mirror because we only need it to retrieve the reference
680 * to the mirror set in write_callback().
681 */
682 bio_set_m(bio, get_default_mirror(ms));
683
684 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL, IOPRIO_DEFAULT));
685}
686
687static void do_writes(struct mirror_set *ms, struct bio_list *writes)
688{
689 int state;
690 struct bio *bio;
691 struct bio_list sync, nosync, recover, *this_list = NULL;
692 struct bio_list requeue;
693 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
694 region_t region;
695
696 if (!writes->head)
697 return;
698
699 /*
700 * Classify each write.
701 */
702 bio_list_init(&sync);
703 bio_list_init(&nosync);
704 bio_list_init(&recover);
705 bio_list_init(&requeue);
706
707 while ((bio = bio_list_pop(writes))) {
708 if ((bio->bi_opf & REQ_PREFLUSH) ||
709 (bio_op(bio) == REQ_OP_DISCARD)) {
710 bio_list_add(&sync, bio);
711 continue;
712 }
713
714 region = dm_rh_bio_to_region(ms->rh, bio);
715
716 if (log->type->is_remote_recovering &&
717 log->type->is_remote_recovering(log, region)) {
718 bio_list_add(&requeue, bio);
719 continue;
720 }
721
722 state = dm_rh_get_state(ms->rh, region, 1);
723 switch (state) {
724 case DM_RH_CLEAN:
725 case DM_RH_DIRTY:
726 this_list = &sync;
727 break;
728
729 case DM_RH_NOSYNC:
730 this_list = &nosync;
731 break;
732
733 case DM_RH_RECOVERING:
734 this_list = &recover;
735 break;
736 }
737
738 bio_list_add(this_list, bio);
739 }
740
741 /*
742 * Add bios that are delayed due to remote recovery
743 * back on to the write queue
744 */
745 if (unlikely(requeue.head)) {
746 spin_lock_irq(&ms->lock);
747 bio_list_merge(&ms->writes, &requeue);
748 spin_unlock_irq(&ms->lock);
749 delayed_wake(ms);
750 }
751
752 /*
753 * Increment the pending counts for any regions that will
754 * be written to (writes to recover regions are going to
755 * be delayed).
756 */
757 dm_rh_inc_pending(ms->rh, &sync);
758 dm_rh_inc_pending(ms->rh, &nosync);
759
760 /*
761 * If the flush fails on a previous call and succeeds here,
762 * we must not reset the log_failure variable. We need
763 * userspace interaction to do that.
764 */
765 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure;
766
767 /*
768 * Dispatch io.
769 */
770 if (unlikely(ms->log_failure) && errors_handled(ms)) {
771 spin_lock_irq(&ms->lock);
772 bio_list_merge(&ms->failures, &sync);
773 spin_unlock_irq(&ms->lock);
774 wakeup_mirrord(ms);
775 } else
776 while ((bio = bio_list_pop(&sync)))
777 do_write(ms, bio);
778
779 while ((bio = bio_list_pop(&recover)))
780 dm_rh_delay(ms->rh, bio);
781
782 while ((bio = bio_list_pop(&nosync))) {
783 if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) {
784 spin_lock_irq(&ms->lock);
785 bio_list_add(&ms->failures, bio);
786 spin_unlock_irq(&ms->lock);
787 wakeup_mirrord(ms);
788 } else {
789 map_bio(get_default_mirror(ms), bio);
790 submit_bio_noacct(bio);
791 }
792 }
793}
794
795static void do_failures(struct mirror_set *ms, struct bio_list *failures)
796{
797 struct bio *bio;
798
799 if (likely(!failures->head))
800 return;
801
802 /*
803 * If the log has failed, unattempted writes are being
804 * put on the holds list. We can't issue those writes
805 * until a log has been marked, so we must store them.
806 *
807 * If a 'noflush' suspend is in progress, we can requeue
808 * the I/O's to the core. This give userspace a chance
809 * to reconfigure the mirror, at which point the core
810 * will reissue the writes. If the 'noflush' flag is
811 * not set, we have no choice but to return errors.
812 *
813 * Some writes on the failures list may have been
814 * submitted before the log failure and represent a
815 * failure to write to one of the devices. It is ok
816 * for us to treat them the same and requeue them
817 * as well.
818 */
819 while ((bio = bio_list_pop(failures))) {
820 if (!ms->log_failure) {
821 ms->in_sync = 0;
822 dm_rh_mark_nosync(ms->rh, bio);
823 }
824
825 /*
826 * If all the legs are dead, fail the I/O.
827 * If the device has failed and keep_log is enabled,
828 * fail the I/O.
829 *
830 * If we have been told to handle errors, and keep_log
831 * isn't enabled, hold the bio and wait for userspace to
832 * deal with the problem.
833 *
834 * Otherwise pretend that the I/O succeeded. (This would
835 * be wrong if the failed leg returned after reboot and
836 * got replicated back to the good legs.)
837 */
838 if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure)))
839 bio_io_error(bio);
840 else if (errors_handled(ms) && !keep_log(ms))
841 hold_bio(ms, bio);
842 else
843 bio_endio(bio);
844 }
845}
846
847static void trigger_event(struct work_struct *work)
848{
849 struct mirror_set *ms =
850 container_of(work, struct mirror_set, trigger_event);
851
852 dm_table_event(ms->ti->table);
853}
854
855/*
856 *---------------------------------------------------------------
857 * kmirrord
858 *---------------------------------------------------------------
859 */
860static void do_mirror(struct work_struct *work)
861{
862 struct mirror_set *ms = container_of(work, struct mirror_set,
863 kmirrord_work);
864 struct bio_list reads, writes, failures;
865 unsigned long flags;
866
867 spin_lock_irqsave(&ms->lock, flags);
868 reads = ms->reads;
869 writes = ms->writes;
870 failures = ms->failures;
871 bio_list_init(&ms->reads);
872 bio_list_init(&ms->writes);
873 bio_list_init(&ms->failures);
874 spin_unlock_irqrestore(&ms->lock, flags);
875
876 dm_rh_update_states(ms->rh, errors_handled(ms));
877 do_recovery(ms);
878 do_reads(ms, &reads);
879 do_writes(ms, &writes);
880 do_failures(ms, &failures);
881}
882
883/*
884 *---------------------------------------------------------------
885 * Target functions
886 *---------------------------------------------------------------
887 */
888static struct mirror_set *alloc_context(unsigned int nr_mirrors,
889 uint32_t region_size,
890 struct dm_target *ti,
891 struct dm_dirty_log *dl)
892{
893 struct mirror_set *ms =
894 kzalloc(struct_size(ms, mirror, nr_mirrors), GFP_KERNEL);
895
896 if (!ms) {
897 ti->error = "Cannot allocate mirror context";
898 return NULL;
899 }
900
901 spin_lock_init(&ms->lock);
902 bio_list_init(&ms->reads);
903 bio_list_init(&ms->writes);
904 bio_list_init(&ms->failures);
905 bio_list_init(&ms->holds);
906
907 ms->ti = ti;
908 ms->nr_mirrors = nr_mirrors;
909 ms->nr_regions = dm_sector_div_up(ti->len, region_size);
910 ms->in_sync = 0;
911 ms->log_failure = 0;
912 ms->leg_failure = 0;
913 atomic_set(&ms->suspend, 0);
914 atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
915
916 ms->io_client = dm_io_client_create();
917 if (IS_ERR(ms->io_client)) {
918 ti->error = "Error creating dm_io client";
919 kfree(ms);
920 return NULL;
921 }
922
923 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
924 wakeup_all_recovery_waiters,
925 ms->ti->begin, MAX_RECOVERY,
926 dl, region_size, ms->nr_regions);
927 if (IS_ERR(ms->rh)) {
928 ti->error = "Error creating dirty region hash";
929 dm_io_client_destroy(ms->io_client);
930 kfree(ms);
931 return NULL;
932 }
933
934 return ms;
935}
936
937static void free_context(struct mirror_set *ms, struct dm_target *ti,
938 unsigned int m)
939{
940 while (m--)
941 dm_put_device(ti, ms->mirror[m].dev);
942
943 dm_io_client_destroy(ms->io_client);
944 dm_region_hash_destroy(ms->rh);
945 kfree(ms);
946}
947
948static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
949 unsigned int mirror, char **argv)
950{
951 unsigned long long offset;
952 char dummy;
953 int ret;
954
955 if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1 ||
956 offset != (sector_t)offset) {
957 ti->error = "Invalid offset";
958 return -EINVAL;
959 }
960
961 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
962 &ms->mirror[mirror].dev);
963 if (ret) {
964 ti->error = "Device lookup failure";
965 return ret;
966 }
967
968 ms->mirror[mirror].ms = ms;
969 atomic_set(&(ms->mirror[mirror].error_count), 0);
970 ms->mirror[mirror].error_type = 0;
971 ms->mirror[mirror].offset = offset;
972
973 return 0;
974}
975
976/*
977 * Create dirty log: log_type #log_params <log_params>
978 */
979static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
980 unsigned int argc, char **argv,
981 unsigned int *args_used)
982{
983 unsigned int param_count;
984 struct dm_dirty_log *dl;
985 char dummy;
986
987 if (argc < 2) {
988 ti->error = "Insufficient mirror log arguments";
989 return NULL;
990 }
991
992 if (sscanf(argv[1], "%u%c", ¶m_count, &dummy) != 1) {
993 ti->error = "Invalid mirror log argument count";
994 return NULL;
995 }
996
997 *args_used = 2 + param_count;
998
999 if (argc < *args_used) {
1000 ti->error = "Insufficient mirror log arguments";
1001 return NULL;
1002 }
1003
1004 dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
1005 argv + 2);
1006 if (!dl) {
1007 ti->error = "Error creating mirror dirty log";
1008 return NULL;
1009 }
1010
1011 return dl;
1012}
1013
1014static int parse_features(struct mirror_set *ms, unsigned int argc, char **argv,
1015 unsigned int *args_used)
1016{
1017 unsigned int num_features;
1018 struct dm_target *ti = ms->ti;
1019 char dummy;
1020 int i;
1021
1022 *args_used = 0;
1023
1024 if (!argc)
1025 return 0;
1026
1027 if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) {
1028 ti->error = "Invalid number of features";
1029 return -EINVAL;
1030 }
1031
1032 argc--;
1033 argv++;
1034 (*args_used)++;
1035
1036 if (num_features > argc) {
1037 ti->error = "Not enough arguments to support feature count";
1038 return -EINVAL;
1039 }
1040
1041 for (i = 0; i < num_features; i++) {
1042 if (!strcmp("handle_errors", argv[0]))
1043 ms->features |= DM_RAID1_HANDLE_ERRORS;
1044 else if (!strcmp("keep_log", argv[0]))
1045 ms->features |= DM_RAID1_KEEP_LOG;
1046 else {
1047 ti->error = "Unrecognised feature requested";
1048 return -EINVAL;
1049 }
1050
1051 argc--;
1052 argv++;
1053 (*args_used)++;
1054 }
1055 if (!errors_handled(ms) && keep_log(ms)) {
1056 ti->error = "keep_log feature requires the handle_errors feature";
1057 return -EINVAL;
1058 }
1059
1060 return 0;
1061}
1062
1063/*
1064 * Construct a mirror mapping:
1065 *
1066 * log_type #log_params <log_params>
1067 * #mirrors [mirror_path offset]{2,}
1068 * [#features <features>]
1069 *
1070 * log_type is "core" or "disk"
1071 * #log_params is between 1 and 3
1072 *
1073 * If present, supported features are "handle_errors" and "keep_log".
1074 */
1075static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1076{
1077 int r;
1078 unsigned int nr_mirrors, m, args_used;
1079 struct mirror_set *ms;
1080 struct dm_dirty_log *dl;
1081 char dummy;
1082
1083 dl = create_dirty_log(ti, argc, argv, &args_used);
1084 if (!dl)
1085 return -EINVAL;
1086
1087 argv += args_used;
1088 argc -= args_used;
1089
1090 if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
1091 nr_mirrors < 2 || nr_mirrors > MAX_NR_MIRRORS) {
1092 ti->error = "Invalid number of mirrors";
1093 dm_dirty_log_destroy(dl);
1094 return -EINVAL;
1095 }
1096
1097 argv++, argc--;
1098
1099 if (argc < nr_mirrors * 2) {
1100 ti->error = "Too few mirror arguments";
1101 dm_dirty_log_destroy(dl);
1102 return -EINVAL;
1103 }
1104
1105 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
1106 if (!ms) {
1107 dm_dirty_log_destroy(dl);
1108 return -ENOMEM;
1109 }
1110
1111 /* Get the mirror parameter sets */
1112 for (m = 0; m < nr_mirrors; m++) {
1113 r = get_mirror(ms, ti, m, argv);
1114 if (r) {
1115 free_context(ms, ti, m);
1116 return r;
1117 }
1118 argv += 2;
1119 argc -= 2;
1120 }
1121
1122 ti->private = ms;
1123
1124 r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh));
1125 if (r)
1126 goto err_free_context;
1127
1128 ti->num_flush_bios = 1;
1129 ti->num_discard_bios = 1;
1130 ti->per_io_data_size = sizeof(struct dm_raid1_bio_record);
1131
1132 ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0);
1133 if (!ms->kmirrord_wq) {
1134 DMERR("couldn't start kmirrord");
1135 r = -ENOMEM;
1136 goto err_free_context;
1137 }
1138 INIT_WORK(&ms->kmirrord_work, do_mirror);
1139 timer_setup(&ms->timer, delayed_wake_fn, 0);
1140 ms->timer_pending = 0;
1141 INIT_WORK(&ms->trigger_event, trigger_event);
1142
1143 r = parse_features(ms, argc, argv, &args_used);
1144 if (r)
1145 goto err_destroy_wq;
1146
1147 argv += args_used;
1148 argc -= args_used;
1149
1150 /*
1151 * Any read-balancing addition depends on the
1152 * DM_RAID1_HANDLE_ERRORS flag being present.
1153 * This is because the decision to balance depends
1154 * on the sync state of a region. If the above
1155 * flag is not present, we ignore errors; and
1156 * the sync state may be inaccurate.
1157 */
1158
1159 if (argc) {
1160 ti->error = "Too many mirror arguments";
1161 r = -EINVAL;
1162 goto err_destroy_wq;
1163 }
1164
1165 ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1166 if (IS_ERR(ms->kcopyd_client)) {
1167 r = PTR_ERR(ms->kcopyd_client);
1168 goto err_destroy_wq;
1169 }
1170
1171 wakeup_mirrord(ms);
1172 return 0;
1173
1174err_destroy_wq:
1175 destroy_workqueue(ms->kmirrord_wq);
1176err_free_context:
1177 free_context(ms, ti, ms->nr_mirrors);
1178 return r;
1179}
1180
1181static void mirror_dtr(struct dm_target *ti)
1182{
1183 struct mirror_set *ms = ti->private;
1184
1185 del_timer_sync(&ms->timer);
1186 flush_workqueue(ms->kmirrord_wq);
1187 flush_work(&ms->trigger_event);
1188 dm_kcopyd_client_destroy(ms->kcopyd_client);
1189 destroy_workqueue(ms->kmirrord_wq);
1190 free_context(ms, ti, ms->nr_mirrors);
1191}
1192
1193/*
1194 * Mirror mapping function
1195 */
1196static int mirror_map(struct dm_target *ti, struct bio *bio)
1197{
1198 int r, rw = bio_data_dir(bio);
1199 struct mirror *m;
1200 struct mirror_set *ms = ti->private;
1201 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1202 struct dm_raid1_bio_record *bio_record =
1203 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
1204
1205 bio_record->details.bi_bdev = NULL;
1206
1207 if (rw == WRITE) {
1208 /* Save region for mirror_end_io() handler */
1209 bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio);
1210 queue_bio(ms, bio, rw);
1211 return DM_MAPIO_SUBMITTED;
1212 }
1213
1214 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
1215 if (r < 0 && r != -EWOULDBLOCK)
1216 return DM_MAPIO_KILL;
1217
1218 /*
1219 * If region is not in-sync queue the bio.
1220 */
1221 if (!r || (r == -EWOULDBLOCK)) {
1222 if (bio->bi_opf & REQ_RAHEAD)
1223 return DM_MAPIO_KILL;
1224
1225 queue_bio(ms, bio, rw);
1226 return DM_MAPIO_SUBMITTED;
1227 }
1228
1229 /*
1230 * The region is in-sync and we can perform reads directly.
1231 * Store enough information so we can retry if it fails.
1232 */
1233 m = choose_mirror(ms, bio->bi_iter.bi_sector);
1234 if (unlikely(!m))
1235 return DM_MAPIO_KILL;
1236
1237 dm_bio_record(&bio_record->details, bio);
1238 bio_record->m = m;
1239
1240 map_bio(m, bio);
1241
1242 return DM_MAPIO_REMAPPED;
1243}
1244
1245static int mirror_end_io(struct dm_target *ti, struct bio *bio,
1246 blk_status_t *error)
1247{
1248 int rw = bio_data_dir(bio);
1249 struct mirror_set *ms = ti->private;
1250 struct mirror *m = NULL;
1251 struct dm_bio_details *bd = NULL;
1252 struct dm_raid1_bio_record *bio_record =
1253 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
1254
1255 /*
1256 * We need to dec pending if this was a write.
1257 */
1258 if (rw == WRITE) {
1259 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1260 bio_op(bio) != REQ_OP_DISCARD)
1261 dm_rh_dec(ms->rh, bio_record->write_region);
1262 return DM_ENDIO_DONE;
1263 }
1264
1265 if (*error == BLK_STS_NOTSUPP)
1266 goto out;
1267
1268 if (bio->bi_opf & REQ_RAHEAD)
1269 goto out;
1270
1271 if (unlikely(*error)) {
1272 if (!bio_record->details.bi_bdev) {
1273 /*
1274 * There wasn't enough memory to record necessary
1275 * information for a retry or there was no other
1276 * mirror in-sync.
1277 */
1278 DMERR_LIMIT("Mirror read failed.");
1279 return DM_ENDIO_DONE;
1280 }
1281
1282 m = bio_record->m;
1283
1284 DMERR("Mirror read failed from %s. Trying alternative device.",
1285 m->dev->name);
1286
1287 fail_mirror(m, DM_RAID1_READ_ERROR);
1288
1289 /*
1290 * A failed read is requeued for another attempt using an intact
1291 * mirror.
1292 */
1293 if (default_ok(m) || mirror_available(ms, bio)) {
1294 bd = &bio_record->details;
1295
1296 dm_bio_restore(bd, bio);
1297 bio_record->details.bi_bdev = NULL;
1298 bio->bi_status = 0;
1299
1300 queue_bio(ms, bio, rw);
1301 return DM_ENDIO_INCOMPLETE;
1302 }
1303 DMERR("All replicated volumes dead, failing I/O");
1304 }
1305
1306out:
1307 bio_record->details.bi_bdev = NULL;
1308
1309 return DM_ENDIO_DONE;
1310}
1311
1312static void mirror_presuspend(struct dm_target *ti)
1313{
1314 struct mirror_set *ms = ti->private;
1315 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1316
1317 struct bio_list holds;
1318 struct bio *bio;
1319
1320 atomic_set(&ms->suspend, 1);
1321
1322 /*
1323 * Process bios in the hold list to start recovery waiting
1324 * for bios in the hold list. After the process, no bio has
1325 * a chance to be added in the hold list because ms->suspend
1326 * is set.
1327 */
1328 spin_lock_irq(&ms->lock);
1329 holds = ms->holds;
1330 bio_list_init(&ms->holds);
1331 spin_unlock_irq(&ms->lock);
1332
1333 while ((bio = bio_list_pop(&holds)))
1334 hold_bio(ms, bio);
1335
1336 /*
1337 * We must finish up all the work that we've
1338 * generated (i.e. recovery work).
1339 */
1340 dm_rh_stop_recovery(ms->rh);
1341
1342 wait_event(_kmirrord_recovery_stopped,
1343 !dm_rh_recovery_in_flight(ms->rh));
1344
1345 if (log->type->presuspend && log->type->presuspend(log))
1346 /* FIXME: need better error handling */
1347 DMWARN("log presuspend failed");
1348
1349 /*
1350 * Now that recovery is complete/stopped and the
1351 * delayed bios are queued, we need to wait for
1352 * the worker thread to complete. This way,
1353 * we know that all of our I/O has been pushed.
1354 */
1355 flush_workqueue(ms->kmirrord_wq);
1356}
1357
1358static void mirror_postsuspend(struct dm_target *ti)
1359{
1360 struct mirror_set *ms = ti->private;
1361 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1362
1363 if (log->type->postsuspend && log->type->postsuspend(log))
1364 /* FIXME: need better error handling */
1365 DMWARN("log postsuspend failed");
1366}
1367
1368static void mirror_resume(struct dm_target *ti)
1369{
1370 struct mirror_set *ms = ti->private;
1371 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1372
1373 atomic_set(&ms->suspend, 0);
1374 if (log->type->resume && log->type->resume(log))
1375 /* FIXME: need better error handling */
1376 DMWARN("log resume failed");
1377 dm_rh_start_recovery(ms->rh);
1378}
1379
1380/*
1381 * device_status_char
1382 * @m: mirror device/leg we want the status of
1383 *
1384 * We return one character representing the most severe error
1385 * we have encountered.
1386 * A => Alive - No failures
1387 * D => Dead - A write failure occurred leaving mirror out-of-sync
1388 * S => Sync - A sychronization failure occurred, mirror out-of-sync
1389 * R => Read - A read failure occurred, mirror data unaffected
1390 *
1391 * Returns: <char>
1392 */
1393static char device_status_char(struct mirror *m)
1394{
1395 if (!atomic_read(&(m->error_count)))
1396 return 'A';
1397
1398 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
1399 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
1400 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
1401 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
1402}
1403
1404
1405static void mirror_status(struct dm_target *ti, status_type_t type,
1406 unsigned int status_flags, char *result, unsigned int maxlen)
1407{
1408 unsigned int m, sz = 0;
1409 int num_feature_args = 0;
1410 struct mirror_set *ms = ti->private;
1411 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1412 char buffer[MAX_NR_MIRRORS + 1];
1413
1414 switch (type) {
1415 case STATUSTYPE_INFO:
1416 DMEMIT("%d ", ms->nr_mirrors);
1417 for (m = 0; m < ms->nr_mirrors; m++) {
1418 DMEMIT("%s ", ms->mirror[m].dev->name);
1419 buffer[m] = device_status_char(&(ms->mirror[m]));
1420 }
1421 buffer[m] = '\0';
1422
1423 DMEMIT("%llu/%llu 1 %s ",
1424 (unsigned long long)log->type->get_sync_count(log),
1425 (unsigned long long)ms->nr_regions, buffer);
1426
1427 sz += log->type->status(log, type, result+sz, maxlen-sz);
1428
1429 break;
1430
1431 case STATUSTYPE_TABLE:
1432 sz = log->type->status(log, type, result, maxlen);
1433
1434 DMEMIT("%d", ms->nr_mirrors);
1435 for (m = 0; m < ms->nr_mirrors; m++)
1436 DMEMIT(" %s %llu", ms->mirror[m].dev->name,
1437 (unsigned long long)ms->mirror[m].offset);
1438
1439 num_feature_args += !!errors_handled(ms);
1440 num_feature_args += !!keep_log(ms);
1441 if (num_feature_args) {
1442 DMEMIT(" %d", num_feature_args);
1443 if (errors_handled(ms))
1444 DMEMIT(" handle_errors");
1445 if (keep_log(ms))
1446 DMEMIT(" keep_log");
1447 }
1448
1449 break;
1450
1451 case STATUSTYPE_IMA:
1452 DMEMIT_TARGET_NAME_VERSION(ti->type);
1453 DMEMIT(",nr_mirrors=%d", ms->nr_mirrors);
1454 for (m = 0; m < ms->nr_mirrors; m++) {
1455 DMEMIT(",mirror_device_%d=%s", m, ms->mirror[m].dev->name);
1456 DMEMIT(",mirror_device_%d_status=%c",
1457 m, device_status_char(&(ms->mirror[m])));
1458 }
1459
1460 DMEMIT(",handle_errors=%c", errors_handled(ms) ? 'y' : 'n');
1461 DMEMIT(",keep_log=%c", keep_log(ms) ? 'y' : 'n');
1462
1463 DMEMIT(",log_type_status=");
1464 sz += log->type->status(log, type, result+sz, maxlen-sz);
1465 DMEMIT(";");
1466 break;
1467 }
1468}
1469
1470static int mirror_iterate_devices(struct dm_target *ti,
1471 iterate_devices_callout_fn fn, void *data)
1472{
1473 struct mirror_set *ms = ti->private;
1474 int ret = 0;
1475 unsigned int i;
1476
1477 for (i = 0; !ret && i < ms->nr_mirrors; i++)
1478 ret = fn(ti, ms->mirror[i].dev,
1479 ms->mirror[i].offset, ti->len, data);
1480
1481 return ret;
1482}
1483
1484static struct target_type mirror_target = {
1485 .name = "mirror",
1486 .version = {1, 14, 0},
1487 .module = THIS_MODULE,
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(&mirror_target);
1510 if (r < 0) {
1511 destroy_workqueue(dm_raid1_wq);
1512 return r;
1513 }
1514
1515 return 0;
1516}
1517
1518static void __exit dm_mirror_exit(void)
1519{
1520 destroy_workqueue(dm_raid1_wq);
1521 dm_unregister_target(&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");