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