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